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![TABLE 6: APPLICATIONS FOR THE FLUIDIZED-BED OPPOSED JET MILL
Cool Delamination / Hard mate- Contamination-free Other
Cover Story grinding deglomeration rial processing
Toner Mica Abrasives Dental ceramics Silica
Powder Talc Technical Fluorescent powders Flame retardants
coating Ceramic Ceramics Silica gel Rare-earth-magnet
heat is converted to kinetic en- Wax pigments Perlite Pharma auxiliaries materials
ergy. The gas can even be accel- Plant Pigments Glass frits Acive pharmaceutical PTFE
protectors Tungsten ingredients (API) Graphite
erated to supersonic speed in a Paints carbide
Laval nozzle. A Laval nozzle is
characterized by its hourglass
shape, which widens down- Feed Feed
stream of the narrowest diame- Transport air
ter in a similar way to Venturis. Air +
Compressed air at 20°C and ground
product
between 6 and 8 bar overpres-
sure is frequently used, in
which case the exit velocity of Air +
ground
the air is approximately 500 product
m/s. If the product permits, the
Grinding
compressed air is not cooled air
downstream of the compres-
sor, and jet mills are operated
at elevated temperatures. Air Grinding
air
velocities of approximately 600
m/s can be achieved in this way.
After exiting the nozzle, the FIGURE 7. The spiral jet mill is relatively simple
speed of the jet drops rapidly
as a result of air and product being terial at the periphery. This transports
sucked in from the surroundings. the feed material into the jets of grind- FIGURE 8. This fluidized-bed opposed-
jet mill has an integrated deflector-wheel
If superheated steam is used as the ing air, where it is comminuted mainly classifier
propellant, it is possible to achieve as the result of impacts between the
speeds of over 1,000 m/s. A significant particles traveling at different speeds. to wear, and no fineness adjustment.
disadvantage of grinding with steam, The air stream in the grinding cham- Spiral jet mills are employed in the
however, is the tricky operation of a ber effects a spiral classification: fine chemicals industry for the dispersion
system where the risk of condensation material is conveyed to the central of pigments. During a dispersion pro-
in the downstream filter is high. This discharge opening, whereas coarse cess, the final particle size is dictated
is the reason why more and more jet material is centrifuged back out to the more by the primary particle size in
mill owners have meanwhile switched periphery. A high pressure builds up the feed material than by the air clas-
from steam operation to compressed in the mill as a result of the air rotat- sification. Large mills have a diameter
air mode. ing at high speed. This makes it neces- of the grinding chamber of approxi-
Increasing demands on the prod- sary to use an injector operated with mately 1 m and consume up to 3,000
uct quality and the development of compressed air to feed the material; m3/h of compressed air. Small mills for
the fluidized-bed opposed jet mill (de- with approximately 30%, the injector product development have diameters
scribed below) have helped jet mill- requires a considerable share of the of only 30 mm.
ing gain acceptance, even though the total air flow. Fluidized-bed jet mills. The fluid-
energy consumption of jet mills is ex- The spiral jet mill has no fineness ized-bed opposed-jet mill came onto
tremely high. Besides taking a look at control. At a constant air flowrate, the the market around 1980. The big ad-
the fluidized-bed opposed jet mill, the feedrate is the main parameter used to vantage of this jet mill, when com-
spiral jet mill, which continues to be adjust the fineness. A high throughput pared with the spiral jet mill, is the
popular in the pharmaceuticals indus- results in coarse product because the integrated deflector-wheel classifier,
try is also considered. spiral is decelerated, and this leads to which, together with the constant air
Spiral jet mill. The spiral jet mill is a coarser classification. flowrate, ensures an extremely con-
a simple piece of equipment. At the pe- The advantages of the spiral jet stant product quality.
riphery of the flat-cylindrical grinding- mill — simple design, simple clean- The nozzles expand the compressed
classifying chamber, compressed air is ing [(clean-in-place (CIP) capable] grinding air horizontally in the grind-
expanded in nozzles that are pitched and simple sterilization [sterilize-in- ing chamber (Figure 8). In the case of
at an angle of between 30 and 50 deg. place (SIP) capable] — have all com- frequent product change — that is,
to the radius (Figure 7). This causes bined to ensure that this machine the desire to completely empty the
a rotating air stream in the grinding has remained the standard machine vessel — additional bin floor nozzles
chamber. The feed material, charged in the pharmaceutical industry for can also be used. The nozzle diameters
to the grinding chamber through an fine grinding. And this is in spite of range from 1 mm with the small mills
injector, becomes caught up in the ro- the disadvantages: high noise level in to 30 mm with the largest ones. The
tating flow of air, is centrifuged and operation (injector), additional gas re- rising flow of air transports ground
ultimately forms a rotating ring of ma- quirement for the injector, sensitivity product to the integrated classifying
30 CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009](https://image.slidesharecdn.com/chemicalengineering200908-130204115317-phpapp01/85/Fine-Grinding-Getting-Up-To-Speed-36-320.jpg)
![Cover Story
TABLE 7: SUITABILITY OF DIFFERENT MILL DESIGNS FOR SPECIFIC APPLICATIONS
Mill design
Material properties Fine Long gap Dual-rotor Classifier Spiral Fluidized-
impact mill mill pin mill mill jet mill bed jet mill
Fineness > 100 μm > 80 μm > 32 μm > 10 μm > 5 μm > 3 μm
Top cut - o - + + +
Mohs' hardness < 3 + + + + + +
Mohs' hardness > 3 o o - o - +
Heat-sensitive materials o o - o + +
Moist materials o + (1) o o - o
Sticky materials o o + (2) - - -
Machine sizes
Rotor diameter, mm 50 – 1,800 200 – 2,800 50 – 1,120 50 – 2,000 30 – 1,000 (3) 40 – 1,800 (3)
Drive power, kW 0.5 – 355 4 – 1,400 2x0.5 – 2x250 0.5 – 500 1,200 (4)
+ ideal; o suitable to a limited degree; - not recommended
Footnotes: (1) The long gap mill is capable of processing products with a high moisture content — even liquid suspen-
sions — provided that the air is preheated adequately; (2) In combination with wide-chamber design; ( ) Diameter of
g ; (3)
grinding chamber; (4) Drive power of compressor
1 6
4
FIGURE 13.
2
7 Flowchart of
a pressure-re-
3 lieved process-
ing system with
classifier mill.
[(A) feed; (B)
5 ground material;
(1) metal sepa-
rator; (2) feed
metering screw;
(3) classifier
mill; (4) reverse
FIGURE 12. A standard impact mill
jet filter; (5) fan;
system is composed of: a feeder (1),
(6) explosion-
magnetic separator (2), a mill plus
barrier valve
safety switch (3), a silencer (4), a
(7) explosion
product collection bin (5), an auto-
venting; (8) fire
matic filter (6) and a fan (7)
extinguishing
system; (9) rup-
for a specific application or to it not ture disk]
being suitable at all. Table 7 gives an
overview of the suitability of various
machine types on the basis of differ- be opened if the rotor is still running. an increasingly insignificant role.
ent criteria. A suction-side silencer (4) reduces the Today, solutions are developed for the
noise at the site of machine installa- individual market segments that are
System engineering tion. A large part of the ground prod- more and more specific, whereby the
An impact mill on its own is not func- uct accumulates directly in the fines peripheral conditions specified by a
tional; it needs a more-or-less elabo- collection bin (5), whereas fine dust is product itself must always be taken
rate system for operation. A standard collected in the automatic filter (6). A into account.
system for the classic impact mill is suction fan (7) compensates the filter
shown in Figure 12. Feed metering resistance in order to maintain a slight Explosion protection
channels or screws (1) ensure a uni- under-pressure in the system and thus Even though dust explosions are
form feedrate. A magnet in the feed prevent formation of dust. The rotary relatively rare, they can cause seri-
chute (2) protects the grinding ele- valve at the base of the fines collection ous damage to people and machines
ments from metallic tramp material. bin discharges the product and serves when they do occur. Besides preven-
The door interlock (3) ensures that as an air-lock. tive measures, such as the avoidance
the mill cannot be switched on if the In times with the focus on custom- of potentially explosive dust concen-
door is open and that the door cannot ized solutions, standard systems play trations, the avoidance of critical oxy-
32 CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009](https://image.slidesharecdn.com/chemicalengineering200908-130204115317-phpapp01/85/Fine-Grinding-Getting-Up-To-Speed-38-320.jpg)
![FIGURE 16. This fine impact mill inside
FIGURE 14. Shown here is a an isolator features a mill housing and
compact grinding system with grinding elements in monobloc design,
pin mill and two air-locks and polished surfaces (Ra = 0.8 μm)
FIGURE 15. Cryogenic grinding
system operated with liquid nitrogen
gen concentrations by inerting and [(A) feed; (B) ground material; (1) feed that the production personnel must
the avoidance of ignition sources, there metering channel; (2) screw cooler be afforded effective protection. This
are a number of design measures that supplied with liquid nitrogen (LN2); (3) has led to the increasing use of isola-
dual-rotor pin mill; (4) automatic filter;
can limit the damage in the event of (5) temperature sensor]
tors (Figure 16). A machine is much
a dust explosion. In laboratories, for more difficult to operate if housed in
example, inerting is often used — like- perature can be cooled to make them an isolator, than under normal condi-
wise in the pharmaceuticals industry. brittle enough to be subsequently tions. Grinding systems in isolators
In the case of large systems, an explo- ground by impact. Cryogenic grinding are unique systems with every detail
sion-pressure, shock-proof design is is used for spices to make sure that designed to users’ needs.
too expensive, and pressure venting the flavor and aroma is preserved. At
and a reduced explosion pressure is the same time, cryogenic grinding also Final remarks
therefore used (Figure 13). Confor- increases the throughput. Other appli- During the last decades impact grind-
mance with the explosion protection cations are the fine grinding of plas- ing has gone through several devel-
directives 94/9/EC for manufacturers tics and rubber. The supply of nitrogen opments. Dust emissions of systems
and 99/92/EC for owners became man- is controlled as a function of the mill have been reduced. Products have
datory in the EU member countries in outlet temperature. The temperatures become finer and finer. Processes
recent years. downstream of the mill often range have become more stable by using
between 0 and –20°C. The nitrogen re- classifiers. Machines have become
Compact system quirement is considerable and usually more reliable in continuous opera-
In the case of brittle products that ranges between 1 and 3 kg of liquid N2 tion. Nowadays customized solutions
have a low grinding energy, there is a per kilogram of product, which natu- are available for many applications.
high mass flowrate of product through rally raises the costs significantly. Future developments will be: machine
the grinding system. Thus, the system Figure 15 shows a cryogenic grind- diagnosis for planned preventative
can be cooled by the product and does ing system operated with liquid ni- maintenance, noise reduction, energy
not need additional cooling by an air trogen. Large sections of the system efficient grinding processes and use of
flow through the system. A compact are insulated to reduce the nitrogen wear-resistant construction materials
system without dust collector can be requirement, and the cold air is circu- to process harder products by impact
designed for these applications. This lated. Operating in the “through-air” grinding. ■
is especially advantageous for poten- mode is out of the question because Edited by Gerald Ondrey
tially dust-explosive products, because freezing water from the air would
the system is so compact that it can cause the mill to ice up.
Author
Bodo Furchner is general
easily be built in a 10 barg design to manager of the technical di-
withstand dust explosions (Figure 14). Pharma systems vision of Hosokawa Alpine
AG (Peter-Dörfler-Str. 13-25,
This ensures a safe operation of the The demands posed by the pharmaceu- D-86100 Augsburg, Germany;
Phone: +49-821-5906-0; Fax:
system and saves investment costs. tical industry are very different, de- +49-821-5906-234; Email:
An example for the use of such com- pending on whether active substances b.furchner@alpine.hosokawa.
com), a position he has held
pact systems is milling sugar, which is or additives are to be processed and since 1993. Prior to this, he
preferably ground with pin discs (see in what form the medicine will be ad- was manager of Hosokawa
Alpine's Test Center Mechan-
also Figure 9). ministered. In the case of highly active ical Processing from 1995–1999, and worked
substances, the batches are relatively in the company’s R&D department since 1987.
Furchner earned a process-engineering degree
Cryogenic grinding small, and thus so are the machines from the Technical University of Munich, as well
as a Ph.D., which he earned while working as
Some materials that are subject to and systems used to process these scientist at the Institute for Process Engineering
plastic deformation at ambient tem- products. Another important point is in the team of Professor Mersmann.
CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009 33](https://image.slidesharecdn.com/chemicalengineering200908-130204115317-phpapp01/85/Fine-Grinding-Getting-Up-To-Speed-39-320.jpg)
![Operations & Maintenance
Solids Processing
Keeping Cooling Water Clean
Source: Nalco Co.
Proper monitoring OH –
Na+
Ca+2
Cl–
and control of O2 Fe+2 SO4–2 O2
water chemistry Fe(OH)3
Fe(OH)2 H+
Water
OH– OH–
Fe0 Fe+2 Fe0
is essential Fe 0
Fe0
e– e– Electrons e– e
–
e– e–
Brad Buecker Anode Steel Cathode
AEC PowerFlow
C
ooling water systems that FIGURE 1. In a basic oxygen corrosion cell, iron dissolution and metal loss occur
rely on cooling towers are a at the anode, and oxygen reduction takes place at the cathode
critical component at chemi- TABLE 1. REPRESENTATIVE
cal process industries (CPI) are supplied from these sources. Table LAKE WATER ANALYSIS
facilities. However, during operation, 1 provides a representative analysis
Ion Concentration, mg/L
these open recirculating systems of the water quality from a lake in
concentrate the contaminants in the the Midwest that supplies a large Calcium 60
makeup water, and as a result, scale power station. Magnesium 12
formation and biological fouling can Although fresh water has relatively Sodium 32
occur. To manage this problem, all low levels of the minerals calcium and
cooling water systems require proper magnesium, scale may form during Potassium 7
chemistry control and monitoring. summer months, even in once-through Chloride 32
Unless prevented, corrosion and the condensers and auxiliary heat ex- Sulfate 77
build up of scale and microbial fouling changers, because of the higher sea-
Bicarbonate 163
can impact cooling efficiency and in sonal water temperatures. Given the
extreme cases even lead to unit shut- huge number of heat exchangers and Nitrate 0.5
down. This article examines some of condensers at refineries, chemical Silica 2
the fundamental concepts and treat- plants, power plants and other chemi- Iron 0.1
ment options that should be consid- cal process facilities, any exchangers
Manganese 0.1
ered to keep open, recirculating cool- that rely directly or indirectly on a
ing systems clean. raw water supply for cooling may be
When handling any water-treatment subject to fouling. minimize corrosion. Nonetheless, cor-
chemicals (both oxidizing biocides and If the water used in an open recir- rosion protection is still important, so
non-oxidizing treatment regimens), culating system has not been prop- we will examine some corrosion fun-
safety is an absolutely critical issue. erly treated to remove unwanted damentals as a precursor to the later
Users should follow all recommended constituents, the dissolved species in discussion of treatment options for
safe-handling procedures and ven- the water will become progressively scale control.
dor recommendations. Adherence to concentrated. As solubility limits be- A typical corrosion cell is shown in
proper safe-handling guidelines, and come exceeded for calcium carbonate, Figure 1. As is true for all electrical
the use of proper personal protective calcium sulfate, magnesium silicate, flow, a circuit must be established for
equipment is essential, as many of the and other compounds, scale will form. the reaction to proceed. In this exam-
aggressive treatment chemicals dis- The buildup of calcium phosphate ple, iron atoms give up two electrons
cussed below will attack human cells, [Ca3(PO4)2] is also of concern in sys- at the anode and the atoms dissolve
just as they attack the microbes they tems where phosphate or phospho- into the solution.
are designed to kill. nates (organic phosphate compounds)
2Fe 2Fe+2 + 4e– (1)
are used for scale and corrosion pre-
Chemical treatment options vention. In fact, at one time calcium The electrons flow through the metal
The discussion that follows focuses phosphate challenged calcium car- substrate to the cathode, where they
on cooling tower systems that take bonate as the most prevalent scale- reduce a common species in the
makeup from fresh water sources, forming substance in such systems, water. In typical neutral to alkaline
such as lakes, rivers, groundwater, or because calcium phosphate deposits cooling waters, the primary reactant
municipal water supplies. The vast can be very heavy and insulating. is oxygen.
majority of the 300,000 or more cool- Many modern chemistry programs
O2 + 2H2O + 4e– 4OH– (2)
ing towers operating in the U.S. today operate under alkaline conditions, to
CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009 43](https://image.slidesharecdn.com/chemicalengineering200908-130204115317-phpapp01/85/Fine-Grinding-Getting-Up-To-Speed-49-320.jpg)
![Operations & Maintenance
The ions formed at the anode and
cathode migrate toward each other, OH OH PO3H2
completing the circuit. The overall cor- P P CH2 C CH2 CH2
rosion reaction is: O O
OH OH OH COOH COOH COOH
2Fe + O2 + 2H2O 2Fe(OH)2 (3)
Ferrous hydroxide [Fe(OH)2] will FIGURE 2. Two commonly used phosphonates (shown here) are 1-hydroxyeth-
ylidene-1,1-diphosphonic acid (HEDP) and 2-phosphono-butane-1,2,4-tricarboxylic
further oxidize to ferric hydroxide acid (PBTC). Phosphonates help to inhibit the formation of calcium-based scale in
[Fe(OH)3] and eventually turn to rust cooling water systems
(Fe2O3 2O).
Water-treatment programs that However, acid feed alone may not course reduce the effectiveness of the
slow down either the anodic or ca- eliminate scaling. Upsets of acid feed phosphonates, and will also increase
thodic reactions, or both, will reduce systems can lead to corrosion or scal- the orthophosphate concentration and
the corrosion rate. (Note: Anodic in- ing, and sulfuric acid introduces sul- the potential for the deposition of cal-
hibitors, if not carefully monitored for fate ions (SO4–2) to the water, which cium phosphate.
residual chemical levels, can lead to may in turn lead to calcium sulfate A common phosphonate treatment
the formation of a few anodic sites in a deposition. Accordingly, supplemen- program might include one or perhaps
large cathodic field. Quick and damag- tal chemicals are normally employed two of the phosphonate compounds,
ing pitting is then likely to occur.) in cooling tower programs to further used in relatively low-mg/L dosages
Just a few decades ago, a very com- minimize scale formation. for primary scale control. For instance,
mon treatment program for cooling One common treatment method dosages as low as 5 mg/L of orthophos-
towers was to use sulfuric acid injec- was the use of phosphates, either phate can be used for additional scale
tion (to remove bicarbonate ions and ortho-phosphate (PO4–2) or phosphate control and corrosion protection, and
minimize calcium carbonate scaling complexes, that would revert to ortho- zinc can be used in dosages as low as
potential) combined with chromate phosphate, to precipitate calcium as 0.5 to 2.5 mg/L (zinc dosage is temper-
(CrO4–2) feed. These chromate-based, calcium phosphate [Ca3(PO4)2]. These ature-dependent). Zinc reacts with the
pH-adjustment programs were very programs also provided corrosion pro- hydroxyl ions generated at cathodes
effective and generally made life easy tection because phosphate will react to form a precipitate [Zn(OH)2], which
for the cooling water chemist. Chro- with ferrous ions (Fe+2) produced at provides additional cathodic protec-
mate establishes a protective surface anodic sites to form a protective bar- tion. Also typically included in this for-
coating that resembles stainless steel. rier, while calcium phosphate precipi- mulation is a small dose of an organic
However, the toxicity of chromate tates in the local alkaline environment polymer for control of calcium phos-
has led to severe restrictions on the at cathodic sites. phate deposition.
use of this chemical, so modern treat- However, even small upsets in Original polymers developed for
ment programs have generally evolved phosphate programs can cause se- these applications contain carboxylic
into alternative, non-chromate meth- vere calcium phosphate fouling. Ac- acid functional groups (COOH), where
ods that operate at a mildly alkaline cordingly, treatment methods have the negatively charged oxygen atoms
pH. Operation at alkaline pH itself evolved to more-forgiving methodolo- bind with calcium to modify crystal
helps to reduce corrosion, but higher gies, where in many cases the back- growth. More advanced compounds,
pH increases the potential for scale bone of these programs is still an such as terpolymers, have a structure
formation, particularly from calcium organic phosphate (a phosphonate) that includes carboxylic, amide (R-
carbonate and calcium phosphate. that is used in conjunction with a CO-NH2), and sulfonic acid (SO3H)
Consider the following example of supplemental polymer to sequester groups for improved reactivity and
untreated water in the cooling system. and modify the crystal structure of resistance to degradation. However,
As the water is cycled, the first com- scale-forming ions and compounds zinc, like many other metals, is falling
pound that tends to come out of solu- (Figure 2). In essence, phosphonates under tighter regulatory guidelines, so
tion is calcium carbonate. attach to deposits as they are form- zinc may no longer be acceptable as an
ing and disrupt crystal growth and additive in many locations.
Ca+2 + 2HCO3– + heat CaCO3 +
lattice strength. One program that has gained much
CO2 + H2O (4)
Careful monitoring and control popularity in recent years is based
A straightforward and often-used of phosphonate programs is still re- upon the use of a phosphino succinic
method to reduce the potential for cal- quired, as overfeed of phosphonates oligomer (PSO) with a supplemental,
cium carbonate scaling is to treat the can lead to calcium-phosphonate de- but slight, orthophosphate dosage and
makeup with sulfuric acid (H2SO4), position. Conversely, phosphonates a polymer to inhibit calcium phos-
where the hydrogen ions (H+) from the exhibit varying degrees of susceptibil- phate deposition. The PSO molecules
acid convert the bicarbonate to carbon ity to degradation from thermal and contain both phosphate-oxygen and
dioxide (CO2). The gas exits from the chemical stresses, where oxidizing bi- carboxylic functional groups.
cooling tower. ocides in particular may cause compo- One complicating factor of the
nent breakdown. Degradation will of above-mentioned programs is that at
H+ + HCO3– CO2 + H2O (5)
44 CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009](https://image.slidesharecdn.com/chemicalengineering200908-130204115317-phpapp01/85/Fine-Grinding-Getting-Up-To-Speed-50-320.jpg)
![100 0
80 20
Operations & Maintenance
Percent ionized
Percent acid
60 40
HOCl HOBr
40 60
the OCl– ion does not allow it to pen- FIGURE 5. In this com-
parison of HOCl versus
etrate bacterial cell walls. The killing HOBr dissociation, note 20 80
efficiency of chlorine dramatically that the dissociation of
declines as pH goes above 7.5. Thus, HOCl occurs at a signifi- 0 100
for the common alkaline scale and cor- cantly lower pH compared 4 5 6 7 8 9 10 11
pH
rosion treatment programs — which to that of HOBr
intentionally maintain pH above 7
TABLE 2. NON-OXIDIZING BIOCIDES
— chlorine chemistry may not be ef-
ficient. Chlorine demand is further Chemical Advantages Disadvantages
affected by ammonia or amines in the 2,2,-dibromo-3- Fast acting, effective against Expensive, degrades
water, which react irreversibly to form nitrilopro- bacteria, degrades quickly to quickly above pH 9, not
the much less-potent chloramines, the pionamide non-hazardous byproducts. very effective against
(DBNPA) fungi and algae.
primary example being monochloro-
amine (NH2Cl). Glutaraldehyde Effective at high pH, effective Degraded by oxidizing
against bacteria. biocides.
Due to safety concerns, liquid bleach
(NaOCl) feed has replaced gaseous Isothiozoline Effective against bacteria and Skin sensitizer.
chlorine at many facilities. The major fungi. Works well with oxidiz-
ing biocides. Active over a
difficulty with using bleach is that wide pH range.
the typical industrial-grade bleach
Quaternary Effective against all organisms Can cause foaming.
contains small amounts of sodium hy- amines depending upon functional Careful handling re-
droxide. Thus, when it is injected into groups attached. quired.
the cooling-water stream it raises the Active over a wide pH range.
pH, if by only a small amount.
A popular alternative is bromine Other oxidants that have been improper monitoring and manage-
chemistry, where a chlorine oxidizer tested for cooling water include hydro- ment of process chemistry engender
and a bromide salt, typically sodium gen peroxide (H2O2) and ozone (O3), excessive costs with regard to reduced
bromide (NaBr), are blended in a but the short lifespan and tendency heat transfer efficiency [2], but pip-
makeup water stream and injected of these chemicals to escape from so- ing and steam-generator tube failures
into the cooling water. The chemistry lution in the cooling tower typically can also increase maintenance-related
produces hypobromous acid (HOBr), make them ineffective in large cool- costs and may even lead to unsched-
which has similar killing powers to ing-water systems. uled process shutdowns, leading to ad-
HOCl, but functions more effectively Another method to help control ditional cost escalations. ■
at alkaline pH. microbes is a supplemental feed of a Edited by Suzanne Shelley
Another factor in favor of bromine is non-oxidizing biocide. Typically, feed
that it does not react irreversibly with is needed on a temporary but regular References
ammonia or amines. However, the pri- basis, perhaps once per week. Table 2 1. Buecker, B., CPI water and steam chemistry,
Chem. Eng., Vol. 115, No. 2, February 2008,
mary disadvantages of bromine use summarizes some of the properties of pp. 30-34.
are that an extra chemical is needed, the most common non-oxidizers. 2. Buecker, B., Steam generation thermody-
and feed systems are a bit more com- Careful evaluation of the microbial namics 101, Power Engineering, Vol. 112, No.
11, November 2008, pp. 106–114.
plex than for bleach alone. species in the cooling water is neces-
Chlorine dioxide (ClO2) has found sary to determine the most effective
Author
some application as an oxidant for biocides. From personal experience, I
Brad Buecker is the tech-
two primary reasons. Its killing power have seen very positive results with nical support specialist
is not affected by pH, and it does not DBNPA on lake water supplies, but with AEC PowerFlow (3125
Roanoke Road, Kansas City,
form halogenated organic compounds. this chemical should not be considered MO 64111; Phone: 816-
531-3800; Email: bbuecker@
Also, chlorine dioxide is more effective a universal killing agent. Also, none aecpowerflow.com). Previ-
in attacking established bio-deposits. of these chemicals should be used or ously, he served as an air-
quality control specialist and
However, ClO2 is unstable and thus tested without appropriate regula- plant chemist for Kansas
must be generated onsite. A common tory approval. They must fit in with City Power & Light. He also
has experience as a chemical
method for onsite generation is the the plant’s National Pollutant Dis- cleaning services engineer, water and wastewa-
reaction of sodium chlorite (NaClO2) charge Elimination System (NPDES) ter system supervisor, and consulting chemist
for Burns & McDonnell Engineers. Earlier in
and chlorine in a slipstream fed to the or equivalent guidelines. his career, Buecker served as a results engineer,
fluegas desulfurization (FGD) engineer, and an-
cooling water, which proceeds as: alytical chemist for City Water, Light & Power
2NaClO2 + Cl2 2ClO2 + 2NaCl (8)
Closing thoughts (Springfield, Ill.). Buecker has written many
articles on steam generation, water treatment,
As discussed in an earlier article by and FGD chemistry, and he is the author of three
Costs are usually several times higher this author [1], CPI technical personnel books on steam generation topics, published by
PennWell Publishing (Tulsa, Okla.). He holds an
due to the fact that more chemicals sometimes focus on process chemistry A.A. in pre-engineering from Springfield College
are required with onsite production without properly monitoring water/ in Illinois, and a B.S. in chemistry from Iowa
State University. He is a member of the ACS,
than for straight halogen treatment. steam chemistry closely. Not only can AIChE, ASME, and NACE.
46 CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009](https://image.slidesharecdn.com/chemicalengineering200908-130204115317-phpapp01/85/Fine-Grinding-Getting-Up-To-Speed-52-320.jpg)
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Fine Grinding: Getting Up To Speed
This document provides information on performance fluids from Dow that can be used in various applications. It discusses how Dow's fluids help achieve high performance levels and productivity in demanding applications, such as heat transfer, lubrication, fluid power, freeze protection, and deicing. It also notes that Dow provides global support to help customers select and implement the right fluids for their needs.
Fine Grinding: Getting Up To Speed
- 1. AUGUST 2009 VISCOSITY: The Basics PAGE 34 www.che.com 8 PAGE 26 REACH: Monitoring Looking Beyond Air Emissions Pre-registration Facts at Your Focus on Fingertips: Boilers & Adsorption Steam Handling Process Control Keeping Cooling and Instrumented Water Clean Safety System Integration
- 2. Performance Fluids fromDow Fluids that Move Your World ™ It takes the right fluids to achieve high levels of performance, help maintain winter aviation productivity and economy. For operating supplies that meet critical safety while contributing to on-time flight departure performance. functional and protection needs in demanding applications, choose www.ucaradf.com performance fluids from Dow. We supply advanced, proven, and reliable solutions for heat transfer, lubrication, fluid power, freeze We stand behind our fluids with a global support team that can and corrosion protection, and deicing. provide the application, technical, regulatory, sales and customer service assistance you require. For fluids that perform, choose ™ † performance fluids from Dow. increase processing efficiency and economics in high temperature processing environments. www.dowtherm.com ™ ™ U.S, Canada, and Mexico: 1-800-447-4369 help prevent system corrosion and freeze Latin America: (+55) 11-5188-9222 damage in water-based HVAC, food and beverage, and other Europe: +800-3-694-6367* or (+32) 3-450-2240 systems. www.dowfrost.com Asia-Pacific: +800-7776-7776* or (+60) 3-7958-3392 ™ help protect circulating systems against corrosion and cavitation erosion damage in gas pipeline compressor engines and other oil and gas service. www.norkool.com ™ reduce wear and extend the life ®TM Trademark of The Dow Chemical Company (“Dow”) or an affiliated company of Dow †SYLTHERM Fluids are manufactured by Dow Corning Corporation and distributed by of industrial, mobile, marine and other equipment while offering The Dow Chemical Company important fire-resistance and economic benefits. www.ucon.com *Toll-free service not available in all countries. Circle 01 on p. 54 or go to adlinks.che.com/23017-01
- 3. Improve bulk dumping4 ways with new TIP-TITE™ dumpers from Flexicon® New TIP-TITE™ Universal Drum Dumper handles New TIP-TITE™ Box/Container Dumper handles New TIP-TITE™ High-Lift Drum Dumper handles drums from 30 to 55 gal (114 to 208 liter) boxes up to 48 in. W x 48 in. D x 44 in. H drums from 30 to 55 gal (114 to 208 liter) (1220 mm W x 1220 mm D x 1118 mm H) TIP-TITE™ dumpers bring newfound efficiencies and cost savings to the age-old task of dumping bulk materials from drums, boxes and containers, redefining this class of everyday plant equipment 1 Stop dust 3 Increase reliability Flexicon offers TIP-TITE™ Dumpers in mild steel TIP-TITE™ Dumpers hydraulically raise and Flexicon engineers and builds TIP-TITE™ with durable industrial finishes, with stainless rotate the container, creating a dust-tight seal Dumpers specifically for fail-safe reliability steel material contact surfaces, or in all-stainless against a discharge hood that mates with a under constant use in demanding environ- models finished to food, dairy, pharmaceutical or gasketted inlet port fitted to any receiving vessel. ments—and backs them 100% with a industrial standards. All are available with Flexicon Pneumatic or manual slide gates control flow. performance guarantee. mechanical or pneumatic conveyors, rotary airlock valves or with flanged outlets to feed any process. 2 Improve safety 4 Cut cost Most importantly, all are engineered, manufac- Ergonomic concerns of manual methods Smooth, safe, dust-free and reliable operation tured, guaranteed and supported by Flexicon— can be eliminated with controlled, automated improves the efficiency of a repetitive task, TIP-TITE™ Dumpers, which incorporate with significant savings in labor and downtime, your single-source solution for virtually any bulk handling problem. features of stringent global safety standards. maximizing your payback. USA UK +44 (0)1227 374710 sales@flexicon.com AUSTRALIA +61 (0)7 3879 4180 1 888 FLEXICON SOUTH AFRICA +27 (0)41 453 1871 X-0719 Also available (left to right): Open Chute Drum Dumpers, Open Chute Box/Container Dumpers and High Lift Drum Dump Filling Systems .com See the full range of fast-payback equipment at flexicon.com: Flexible Screw Conveyors, Pneumatic Conveying Systems, Bulk Bag Unloaders, Bulk Bag Conditioners, Bulk Bag Fillers, Bag Dump Stations, Drum Dumpers, Box Dumpers, Weigh Batching and Blending Systems, and Automated Plant-Wide Bulk Handling Systems ©2009 Flexicon Corporation. Flexicon Corporation has registrations and pending applications for the trademark FLEXICON throughout the world. Circle 04 on p. 54 or go to adlinks.che.com/23017-04
- 4. Mighty power ina small package. www.honeywell.com/ps/experionls Circle 05 on p. 54 or go to adlinks.che.com/23017-05
- 5. AUGUST 2009 IN THIS ISSUE VOLUME 116, NO. 8 COMMENTARY 5 Editor’s Page A new ‘lease’ on CPI life? While the worst of the recession may very www.che.com well be over for the global econ- omy in general, COVER STORY the downstream 26 Cover Story Fine Grinding effects in the With Impact Mills A primer chemical process on which mill to use for various industries (CPI) are types of products not yet behind us NEWS DEPARTMENTS 11 Chementator Capacity to double for an oil-shale process; Letters . . . . . . . . . 6 A silver-based antimicrobial; Scaleup for a ‘downer’ FCC Calendar . . . . . . 8, 9 process; Diamond lubricant cuts Who’s Who . . . . . 24 friction and increases equip- ment life; Making fine particles Reader Service of inhalable drugs; Cellulose- page . . . . . . . . . . 54 to-aromatics process simplifies Economic BTX production; Biobased suc- Indicators . . . 55, 56 cinic acid pilot effort under- way; Green honors; Making SunCatchers instead of cars; ADVERTISERS An alternative to chlor-alkali; A Classified replacement for Cr+6; Weed- Advertising . . 49–52 based biodiesel; and more EQUIPMENT & SERVICES Advertiser Index . 53 16 Technology Showcase Monitoring Air Emissions New requirements are spurring 24D-1 New Products & Services strong demand in air pollution monitoring (Domestic Edition) Coriolis meters for low- COMING IN flow applications; Test pH, conductivity, dis- SEPTEMBER 18 Newsfront Today’s SIS: Integrated Yet solved oxygen and ion concentrations; Con- Independent Bringing process control and Look for: Feature dition monitoring and analysis integrated in instrumented safety systems together while Reports on Multi- an automation system; An optimum valve still keeping them separate provides benefits variable Predictive for reciprocating pumps; This range of flow- beyond risk reduction Control; and Water meters and controllers is now more flex- Supply and Reuse; ible; This pump provides precise control in ENGINEERING Engineering Prac- low-flow applications; An aseptic valve for tice articles on 23 Facts At Your Fingertips Adsorption critical areas; A new spray dryer for labo- Evaluating the Safety This one-page guide explains various adsor- ratories; Download CAD drawings for free; Record of CPVC bent properties and provides the correspond- Support EU regulations for classification, Piping; and A New ing equations labeling and packaging; and more Design Approach for 34 Feature Report Viscosity: The Basics 47 Focus Boilers & Backmixed Reactors; An important concept, sometimes forgotten, Steam Handling A Solids Processing is that viscosity is not a single-point measure- These new resins are article on Measur- ment. Basic concepts and terminology are an alternative to metal ing Fines in Polymer reviewed and techniques for quantifying boiler components; Processing; A Focus viscosity are addressed Detect variability in on Valves; News boiler operation for articles on Chemical 40 Engineering Practice REACH: Looking improved efficiency; Engineering Salaries; Beyond Pre-registration The next steps to Ultra-high efficiency and Plant Security; ensuring compliance are significantly more condensing boilers for tough conditions; Facts at Your Fin- complex This burner offers ultra-low NOx emissions; gertips on Heat 43 Operations & Maintenance Keeping Position sensors provide feedback of steam Transfer; An ISA Cooling Water Clean Proper monitoring control valves; For small-scale applications, Show Preview; and control of water chemistry is essential use this steam generator; and more and more CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009 3
- 6. © 2009 SwagelokCompany Contrary to what you may think, we’re much more than a tube fitting company. And we have our obsession with Customer Focus to thank for that. Yes, we’re In addition to tube fittings, known throughout the world for our tube fittings. And yes, we’ve been at it for over 60 years. But when companies are looking harder than ever for greater value, it’s we also make valves, our broad range of products, including orbital welders, modular systems, and a regulators, filters, complete line of hose, that helps us offer more than you expect. See for yourself at swagelok.com/moreproducts. and happier customers. Circle 06 on p. 54 or go to adlinks.che.com/23017-06
- 7. Winner of EightJesse H. Neal Awards for Editorial Excellence Editor’s Page Published since 1902 An Access Intelligence Publication A new ‘lease’ on CPI life? hile the worst of the recession may very well be over for the global PUBLISHER MIKE O’ROURKE Publisher morourke@che.com EDITORS ART & DESIGN DAVID WHITCHER Art Director/ Editorial Production Manager dwhitcher@che.com W S economy in general, the downstream effects in the chemical pro- cess industries (CPI) will take awhile to flush themselves out. Second quarter financial reports were released last month, with most of PRODUCTION t the good news loosing luster in the shadow of the same period last year. REBEKKAH J. MARSHALL Editor in Chief MICHAEL D. KRAUS M Meanwhile, credit options remain tight. Based on these factors alone, rmarshall@che.com VP of Production & Manufacturing mkraus@accessintel.com t the job of any chemical engineer who must justify capital expenditures DOROTHY LOZOWSKI Managing Editor STEVE OLSON i is difficult at best. But, emerging flexibility in how the CPI pays for both dlozowski@che.com Director of Production & e equipment and services could change the way we look at equipment im- Manufacturing GERALD ONDREY (Frankfurt) solson@accessintel.com p provements, even beyond this particular downturn. Senior Editor gondrey@che.com WILLIAM C. GRAHAM The new approach is a twist on the familiar model of looking at so-called Ad Production Manager KATE TORZEWSKI bgraham@che.com l lifecycle costs or total costs of ownership. For years, vendors have used life- Assistant Editor ktorzewski@che.com MARKETING c cycle cost analysis as a selling point for premium equipment and services, SCOTT JENKINS HOLLY ROUNTREE a arguing that the initially higher up-front investment will save the cus- Associate Editor Marketing Manager t tomer money over the longterm. But at the bottom of a recession and the sjenkins@che.com hrountree@accessintel.com AUDIENCE l last half or quarter of a fiscal year, longterm thinking is often superseded CONTRIBUTING EDITORS DEVELOPMENT b by short-term constraints. Seeing the writing on the wall, a number of SUZANNE A. SHELLEY SYLVIA SIERRA sshelley@che.com Senior Vice President, e equipment and service providers in the software, automation and control CHARLES BUTCHER (U.K.) Corporate Audience Development f field have been working on creative ways around such obstacles. In short, cbutcher@che.com ssierra@accessintel.com t they are transforming capital expenditures into operating ones, thereby PAUL S. GRAD (Australia) JOHN ROCKWELL pgrad@che.com Vice President, a avoiding the hurdle of large up-front investments altogether. TETSUO SATOH (Japan) Audience Development Chemical One such example is the Lifecycle Management (LCM) program offered jrockwell@accessintel.com tsatoh@che.com LAURIE HOFMANN b by Honeywell Process Solutions (Phoenix, Ariz.; www.honeywell.com/ps). In JOY LEPREE (New Jersey) Audience Marketing Director a multi-year service agreement, Honeywell and the customer establish an au- jlepree@che.com lhofmann@Accessintel.com GERALD PARKINSON t tomation roadmap that leads to either an “electronic refresh” or a complete TERRY BEST (California) gparkinson@che.com Audience Development Manager m migration during the term of the contract, says Jose Simon, business director EDITORIAL tbest@accessintel.com L Lifecycle Services. The key here, though, is that the LCM program offers both ADVISORY BOARD GEORGE SEVERINE f flexibility and predictability in how the choices are financed. The costs can be Fulfillment Manager JOHN CARSON gseverine@accessintel.com r redefined as maintenance expenses, for example. “Instead of paying in one Jenike & Johanson, Inc. DAVID DICKEY JEN FELLING b bucket, you pay over time,” Simon says, citing five years as an example term. List Sales, Statlistics (203) 778-8700 MixTech, Inc. j.felling@statlistics.com Such an option is especially attractive for the large number of aging MUKESH DOBLE CONFERENCES p plants around the world, which are looking at high maintenance bills in IIT Madras, India HENRY KISTER DANA D. CAREY t the coming years, anyhow. If these plants can redirect the funds that would Director, Global Event Sponsorships Fluor Corp. dcarey@chemweek.com b be needed for repair into procuring newer models that are also cheaper to TREVOR KLETZ o operate, the approval process becomes a lot easier. A CPI plant can start Loughborough University, U.K. PECK SIM GERHARD KREYSA Senior Manager, d down the path to modernization today and get there incrementally with Conference Programming DECHEMA e.V. psim@chemweek.com l less financial risk. RAM RAMACHANDRAN BEATRIZ SUAREZ And in the wake of second quarter earnings that were announced last BOC Director of Conference Operations bsuarez@chemweek.com m month, options with less financial risk look better and better. Even com- INFORMATION SERVICES ROBERT PACIOREK CORPORATE p panies that have seasoned the storm reasonably well have a lot of eco- Senior VP & Chief Information Officer STEVE BARBER n nomic ground to recover. The Saudi Basic Industries Corp. (SABIC; Ri- rpaciorek@accessintel.com VP, Financial Planning & Internal Audit sbarber@accessintel.com y yadh, Saudi Arabia; www.sabic.com), for instance, reported a 76% drop in CHARLES SANDS Senior Developer BRIAN NESSEN i income from that of the same quarter in 2008 due to the sharp decline in Web/business Applications Architect Group Publisher d demand and the prices of petrochemicals, plastics and metals. Meanwhile, csands@accessintel.com bnessen@accessintel.com D DuPont (Wilmington, Del.; www.dupont.com) reported a 61% drop, PPG HEADQUARTERS I Industries (Pittsburgh, Pa.; www.ppg.com) experienced a 42% drop, and 110 William Street, 11th Floor, New York, NY 10038, U.S. Tel: 212-621-4900 Fax: 212-621-4694 t the list goes on. EUROPEAN EDITORIAL OFFICES To these and other CPI firms that must protect their Zeilweg 44, D-60439 Frankfurt am Main, Germany b budget over the remainder of their 2009 fiscal year, the Tel: 49-69-2547-2073 Fax: 49-69-5700-2484 p prospect of shoring up longterm improvements without CIRCULATION REQUESTS: Tel: 847-564-9290 Fax: 847-564-9453 t taking an immediate budget hit probably sounds like Fullfillment Manager; P.O. Box 3588, a an unrealistic expectation. In any case, the potential Northbrook, IL 60065-3588 email: clientservices@che.com i is quite intriguing. Imagine if the economic recovery of ADVERTISING REQUESTS: see p. 54 t today’s CPI were paired with safer, more reliable and For photocopy or reuse requests: 800-772-3350 or info@copyright.com For reprints: chemicalengineering@theygsgroup.com m more efficient operations for tomorrow. Rebekkah Marshall CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009 5
- 8. Bartlett-Snow™ Rotary Calciners for the Activation of Carbon Letters Custom designed to meet your processing require- ments, Bartlett-Snow™ Rotary Calciners provide a highly effective and efficient means for the continuous Optimal cooling systems activation of carbonaceous materials at high tempera- The following comments relate to the May article, Op- tures under controlled atmospheric conditions. timal Cooling Systems for Coastal Plants (pp. 45–48). 1. The psychrometric chart (Figure 4, p. 47) lacks the The calciner consists of wet bulb temperatures. These are essential for using a cylindrical rotating the chart and are represented by the inclined lines. tube, housed in a gas ˆ 2. Equation (1) on p. 46 is incorrect. Firstly, Pwater is or electric furnace, pos- the partial pressure of water vapor in air at ambient sat itively sealed to prevent temperature, and Pwater is the saturation pressure of air infiltration. Product water vapor in air at ambient temperature. Secondly, quality is optimized with the equation that defines the relative humidity should be multiplied by 100, because the relative humidity of a design that establishes and maintains the tempera- air is expressed in percentage. ture profile required for the process. Giovanni S. Crisi Sao Paulo, Brazil Special internal flight design promotes gentle tumbling Author’s reply action and provides for uniform exposure to the internal 1. The psychrometric chart mentioned in the article is atmosphere and efficient heat transfer. just a descriptive chart that has been included in the article not as a reference for design but for explana- tion of different scenarios included in the article. So 4525 Weaver Pkwy., Warrenville, IL 60555 the inclusion of all the properties of air in the chart Toll Free: 877.661.5509 is not necessary for the mentioned purpose. Complete Air Preheater Company TM Raymond Operations Email: info@airpreheaterco.com and accurate psychrometric data can be found in many chemical and mechanical engineering handbooks. www.bartlettsnowcalciners.com 2. Firstly: Partial pressure is only used for the gas Circle 07 on p. 54 or go to adlinks.che.com/23017-07 phase (and not liquid or solid phases), so partial pres- sure of water means pressure of water vapor and there is no difference between the two descriptions. Secondly: The definition of relative humidity in all ref- erences is the ratio of partial pressure of water vapor to saturated vapor pressure of water at the ambient temperature (dry bulb temperature). But expression of it is normally performed as percentage due to fluency. Postscripts, corrections July, The Shotgun Approach, pp. 44–48: Equation (2) contains an error. The correct equation should have Sd, not Sb, and appears below: Pmax ⋅ Dbo t= (2) (2 ⋅ Sd + Pmax ) Meanwhile, the author would like to point out that there is a potential risk that the operating conditions using steel shot, as summarized in Table 3, could re- sult in boiler tube damage. To minimize this risk, the steel shot used in the shotgun ammunition should be annealed by appropriate heat treatment before use. In doing so the shot, instead of the tubes, will preferen- tially deform on impact. Additionally, the “Arrangement of Equipment” sketch on p. 47 is meant to be used only when the interior of the boiler operates below atmospheric pressure. The arrange- ment must be appropriately modified when the interior of the boiler operates above atmospheric pressure. In either case external insulation must be provided on that portion of the barrel extending inside the boiler wall. A revised version of the article may be obtained by searching for the article title at www.che.com Circle 08 on p. 54 or go to adlinks.che.com/23017-08 6 CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009
- 9. Do you seea ladybug? We also see an opportunity for industry to benefit from protecting the environment. Managers within the industrial sector face the never-ending issue of balancing business performance and environmental compliance goals. As the world reference in environmental services, Veolia Environnement helps industry achieve sustainable objectives through our four core service areas: water services and technologies, waste services, energy and facility management, and transportation and logistics. The environment is our universal challenge. veolianorthamerica.com Circle 09 on p. 54 or go to adlinks.che.com/23017-09
- 10. Calendar NORTH AMERICA ISA's 4th Annual Marketing and Sales Summit: Managing Through the Turbulence and Tumult. International Society of Automation (ISA; Research Tri- angle Park, N.C.). Phone: 919-549-8411; Web: isa.org/mktsales Boston, Mass. September 9–11 24th Annual WateReuse Symposium. WateReuse Assn. (Alexandria, Va.), and co-sponsored by the Ameri- can Water Works Assn. (Denver, Colo.) and the Water Environment Federation (Alexandria, Va.). Phone: 703-548-0880; Web: watereuse.org Seattle, Wash. September 13–16 38th Turbomachinery Symposium. The Turbomachin- ery Laboratory at Texas A&M University (College Station, Tex.), co-located with the ASME Gas Turbine Users Symposium 2009; Phone: 979-862-1012; Web: turbolab. tamu.edu/articles/turbo_symposium Houston, Tex. September 14–17 ASM Heat Treating Society Conference Exposition. ASM International (Novelty, Ohio.). Phone: 805-677-4288; Fax; 805-654-1676; Web: asminternational.org Circle 10 on p. 54 or go to adlinks.che.com/23017-10 Indianapolis, Ind. September 14–17 9th Annual SPE Automotive Composites Confer- Harness the power ence & Exhibition. Society of Plastics Engineers Inter- national (SPE) Automotive Division (Troy, Mich.). Phone: of positive press. 248-244-8993; Web: speautomotive.com/comp.htm Troy (Detroit), Mich. September 15–17 OSHA Dust Explosion Inspection Preparatory Training Course. Chilworth Technology (Plainsboro, Custom reprints from Chemical Engineering N.J.). Phone: 609-799-4449; Web: chilworth.com/ could be one of the smartest marketing OSHAtrainingcourse.pdf decisions you make. Columbus, Ohio September 24 ACEEE 5th National Conference on Energy Ef- ficiency as a Resource. American Council for an Energy-Efficient Economy (Washington, D.C.). Phone: 302-292-3966; Web: aceee.org/conf/09ee/09eeindex.htm Chicago September 27–29 2009 Gasification Technologies Conference. Gasification Technologies Council (Arlington, Va.). Phone: 703-276-0110; Web: gasification.org Colorado Springs, Colo. October 4–7 Contact The YGS Group at 717.399.1900 x100 or International Acid Gas Injection Symposium. learn more online at www.theYGSgroup.com/reprints Sphere Technology Connection Ltd. (Calgary, Alta.). Phone: 403-619-6215; Web: spheretechconnect.com Calgary, Alta. October 5–6 The YGS Group is the authorized provider of WaterSmart Innovations Conference and Exposi- custom reprints from Chemical Engineering. tion. American Waterworks Assn. (AWWA; Denver, Colo.), Southern Nevada Water Authority, and U.S. Environmen- tal Protection Agency. Fax: 702-731-3580; Web: 8 CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009
- 11. FP4/SH.C.GB watersmartinnovations.com Las Vegas, Nev. October 7–9 5th Annual Comsol Conference 2009. Comsol (Bur- lington, Mass.). Phone: 781-273-3322; Web: comsol.com/ conference2009/usa/ Boston, Mass. October 8–10 WEFTEC 09. Water Environment Federation (WEF; Arlington,Va.). Phone: 708-344-9070; Web: weftec.org Orlando, Fla. October 10–14 BioProcess International Conference & Exhibi- tion. IBC Life Sciences (Westborough, Mass.). Phone: 800-390-4078; Web: ibclifesciences.com/bpi/us Raleigh, N.C. October 12–16 Centrifugal Compressor Operations for 21st Cen- tury Users — Short Course. The Turbomachinery Laboratory at Texas A&M University (College Station). Phone: 979-845-7417; Web: turbolab.tamu.edu/articles/ centrifugal_compressor_operations_for_21st_century Houston October 27–29 EUROPE RadTech Europe 2009. RadTech Europe Association (Hague, Netherlands). Phone: + 31 70 3123920; Web: european-coatings/radtechcom Nice, France September 13–15 14th International Congress for Battery Recycling. ICM AG (Birrwil, Switzerland). Phone: + 41 (0) 62 785 Conveying Palletizing Packaging 1000; Fax: + 41 (0) 62 785 1005; Web: icm.ch Geneva, Switzerland September 16–18 24th European Photovoltaic Solar Energy Confer- ence and Exhibition 2009. WIP Renewable Energies BEUMER stretch hood® (Munich, Germany). Phone: +49 (0) 6181 9828042; Web: The powerful packaging www.photovoltaic-conference.com Hamburg, Germany September 21–25 solution for the chemical Entsorga-Enteco 2009: The International Trade industry. Fair for Waste Management & Environmental Tech- nology. Koelnmesse (Chicago, Ill.). Phone: 773-326-9925; Web: entsorga-enteco.com Cologne, Germany October 27–30 Optimal safety for all palletized loading units. Proven reliable in all weather conditions and ASIA & ELSEWHERE keeps its appearance at the same time. The 18th international Conference on Plastic Optical high-capacity packaging machine, BEUMER Fibers 2009. Magic Touch Consultancies (International) stretch hood®, efficiently combines the latest Pty Ltd (Sydney, Australia). Phone: +61 2 9524 1799; Web: control technology, sophisticated function pof2009@mtci.com.au modules and secure film handling. See Syndney, Australia September 9–11 for yourself. You can find more information 4th World Recycling Forum Shanghai '09. ICM AG about the BEUMER company and its (Birrwhil, Switzerland). Phone: + 41 62 785 1000; Web: products on the Internet. ich.ch Circle 11 on p. 54 or go to Shanghai, China November 10–13 adlinks.che.com/23017-11 Suzanne Shelley www.beumer.com
- 12. Circle 12 onp. 54 or go to adlinks.che.com/23017-12
- 13. Edited by GeraldOndrey August 2009 C2 Capacity to double Oil shale (6 mm) C1 Solids for an oil-shale process VD ESP Stack Gas VD = Venturi dryer utotec GmbH (Oberursel, Germany), a Ash O C = Cyclone bleed ESP = Electrostatic 100% daughter company of Outotec Oy precipitator (Helsinki, Finland; www.outotec.com) has re- BFW = Boiler feed ceived a 109-million contract for the design, WHB water Bag house CW = Cooling water delivery, construction and commissioning of Air Fly ash CWR = Cooling water a new oil-shale processing plant to be built return C3 in Narva, Estonia for Eesti Energia (Tal- CW CWR C4 RC = Recycle cooler WHB = Waste heat lin, Estonia; www.energia.ee). Scheduled for Recycle ash CFB boiler commissioning in early 2012, the facility will CFB = Circulating Air fluidized bed process over 2.2-million metric tons (m.t.) of RC Ash bleed Water FBC = Fluidized oil shale per year, producing approximately BFW Steam bed cooler FBC 290,000 m.t./yr of crude oil. The plant will be Retort Ash Coke Ash the first commercial application of the En- Mixer efit-280 process, a modified Galoter process Oil production Air BFW Air Steam developed by the two companies. plant The solid heat carrier process (Galoter pro- technology (flowsheet), has the advantages cess) was first introduced in 1953, and scaled — besides doubling the unit capacity — of Bioplastic up to 140 m.t./h (Enefit 140 process) in the high thermal efficiency and the complete DSM Engineering Plastics 1980s. Currently, two Enefit-140 units, oper- combustion of the spent shale after the oil (Sittard, Netherlands; www. ated by Eesti Energia Oil & Gas in Narva, has been extracted, says Peter Weber, presi- dsm.com) has introduced are converting about 1.5-million m.t./yr of oil dent metals processing, Outotec GmbH. Most EcoPaXX, a biobased, high- shale into about 160,000 m.t./yr of oil. In the of the heat is recovered to produce steam for performance engineering Enefit 140 process, oil shale is first ground to electric power generation. The ash from the plastic that is said to have a zero carbon footprint (100% a size of less than 20 mm, dried in a lift-pipe, process is free of organic carbon and can be carbon neutral from cradle to then mixed with hot (800°C) ash produced by landfilled, and the offgas from the process grave). Approximately 70% combustion of spent oil shale in a separate meets European regulations, he adds. Al- of EcoPaXX is made from furnace. The mixture is then pyrolyzed in a though production costs are not disclosed, building blocks derived from retort at 520°C. The pyrolysis gas is then sep- Weber says the process is economical for an Castor oil. Based on the long- arated from the spent shale in a cyclone, and oil price of $65/bbl (Brent). The two firms chain polyamide (PA), PA 410, the ash and semi-coke transported to the sep- established a joint venture to commercial- the new plastic features low arate furnace to make hot ash for pyrolysis. ize and market Enefit, targeting the large moisture absorption and high Enefit, which combines the Galoter pro- oil-shale deposits found in the U.S., Brazil, (250°C) melting point — the cess with Outotec’s circulating fluidized-bed China, Jordan, Russia and Estonia. highest of all bioplastics — and a high crystallization rate. Such properties make the ma- A silver-based antimicrobial terial suitable for automotive and electrical applications. ure Bioscience (El Cajon, Calif.; www.pure- silver in a solution of organic acid that is the P bio.com) has developed silver dihydrogen citrate (SDC), the first antimicrobial approved product of an electrolytic process. The stable bond of the silver ion in SDC allows the Ag+ Weed-based biodiesel Biofuels Manufacturers of Il- by the U.S. Environmental Protection Agency to remain in solution while still making it linois (BMI; Peoria, Ill.; www. (EPA; Washington, D.C.) in 30 years, with ap- bio-available. Microorganisms view the acid bmibiodiesel.com) will de- plications in the pharmaceutical, personal solution as a food source, allowing the pico- velop, construct and operate a care, household, food and textile markets. scale SDC molecule to enter as well. The Ag+ 45-MM gal/yr (expandable to Pure produces both a pre-formulated, ready- then denatures the microbe’s DNA, stopping 60-MM gal/yr) biodiesel plant, to-use product, and an SDC concentrate for its ability to replicate and killing it. beginning construction as addition to other products. It is highly effec- Aqueous SDC is colorless, odorless, taste- early as this month. In addition tive as a hard-surface cleaner, killing the No- less and non-caustic, and it formulates well to using traditional crops, BMI rovirus, MRSA, VRE, E. coli, some influenza with other compounds. It is highly toxic to is working on the development viruses, as well as other dangerous bacteria bacteria, fungi and viruses, but it is non- of pennycress as biodiesel feedstock. As a weed, penny- and viruses. It kills bacteria within 30 s and toxic to humans and animals, having the cress is unconnected to the has a residual killing capability of up to 24 h lowest EPA toxicity category rating of IV. issue of growing food for fuel. after application, unlike other antimicrobials This safe technology was approved by the It grows in the winter, allowing that disappear upon evaporation. EPA in June as an active ingredient in the (Continues on p. 13) The technology consists of stabilized ionic sanitation of food-contact surfaces. Note: For more information, circle the 3-digit number on p. 54, or use the website designation. CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009 11
- 14. C HEMENTATO R Regenerated catalyst containing tower Scaleup for a ‘downer’ FCC process Raw oil n October, Nippon Oil Corp. (Tokyo, general manager of the Techni- I Japan; www.eneos.co.jp) will start constructing a high-severity fluidized- cal Service Department, com- mented expectings to start roy- Downflow reactor Catalyst flow Catalyst upflow tube catalytic cracking (HS-FCC) unit, the alty business through licensing first in the world that can produce large this technology. In 2009, the amounts of propylene from heavy fuel Ministry of Economy, Trade and Products oils. The unit, located at Mizushima Re- Industry (METI) will supply Catalyst finery (Kurashiki-City), will start up in two thirds of the approximately washing tower Catalyst early 2011. The 3,000 bbl/d facility is 100 $46 million for the project. regeneration tower times larger than the 30 bbl/d HS-FCC In the HS-FCC process, heavy Steam demonstration unit that was developed oil is injected into a downflow Air for regeneration in collaboration with Japan Coopera- reactor with powdered catalyst, tion Center, Petroleum (JCCP), Petro- where the oil is decomposed within 0.5 s yield is low compared to FCC but rather leum Energy Center (PEC), and Saudi at 600°C. (A conventional FCC typically high compared to other processes. The Aramco (CE, December 2001, p. 21), and operates at about 500°C, with a contact process can produce 34% gasoline and the company says it will scale up by an- time of 1–4 s.) The propylene yield is 20% propylene, compared to about 50% other factor of 10 in a few years. best among all propylene production gasoline and 5% propylene achieved in Hiroji Adachi, executive officer and processes, and high-octane gasoline conventional FCC risers. Diamond lubricant cuts friction and increases equipment life he lifetime of steel bearings can be tact and spalling, and reduces friction. In side-by-side tests of bearings run T extended by up to eight times by a new synthetic diamond “lubricant,” ac- The only contact is between the smooth diamond coatings, says Christopher Ar- by identical motors, bearings treated by the NanoLube product ran cool at cording to its developer, NanoLube, nold, president of NanoLube. 15,700 rpm, while bearings using a con- Inc. (Lombard, Ill.; www.diamondlube. The key to the technology is the com- ventional lubricant overheated, as did com). The lubricant consists of 0.1–4-nm pany’s low-energy plasma process, which the motor, at 6,400 rpm. Arnold says the diamond spheres that are dispersed in produces the tiny spheres from vapor- treatment cost depends on the applica- a light carrier oil (about 5 wt.%) and ized carbon in an electrical field. This tion. He estimates, for example, that it coated onto the bearings and other fric- provides advantages over other syn- would cost about $150 to treat a $20,000 tion-prone surfaces of a machine. When thetic diamond processes, says Arnold. compressor, but the reduction in friction the machine is activated, the spheres For example, conventional synthetic dia- would increase the life of the moving become embedded in the surface of the monds, produced from graphite at high parts eight-fold. He adds that the coat- metal, forming a smooth, protective bar- temperature and pressure, are crystal- ing can operate in temperatures from rier that prevents metal-to-metal con- line with abrasive edges, not spherical. –100 to 2,000°F. Making fine particles of inhalable drugs team from the School of Chemical ergized rapid release of organic solutions ized with nitrogen and sealed. By rap- A Sciences and Engineering, at the University of New South Wales (Sydney, and the anti-solvent capability of super- critical CO2 for the precipitation of phar- idly depressurizing the vessel through a tube (about 1-mm inner dia.), the solu- Australia; www.unsw.edu.au), has devel- maceutical compounds from organic sol- tion is atomized into another vessel con- oped a process for the micronization of vents. It exploits a pressure differential taining supercritical CO2 under near- insulin called Arise (Atomized Rapid In- and rapid injection to atomize organic isothermal conditions. The extraction of jection for Solvent Extraction). Accord- solutions into a vessel containing super- organic solution and the precipitation ing to BioParticle Technologies Pty. Ltd. critical CO2 without using capillary noz- of previously dissolved pharmaceutical (BPT; Sydney; www. bioparticletech- zles. This results in a more homogeneous compound occur at this stage. nologies.com), the company marketing distribution of organic solution for pre- The process was successfully imple- Arise, the technology offers several ad- cipitation to occur within the entire ves- mented to generate dry powders of bo- vantages over other existing supercriti- sel containing the supercritical CO2. The vine insulin with properties that were cal fluid technologies. The team leader, absence of capillary nozzles also avoids highly tunable as a function of anti- professor Neil Foster who invented the the problems associated with them, such solvent pressure. With a pre-injection Arise process, says “this technology al- as the tendency to block and clog during pressure of 120 bar CO2 at 40°C, Arise lows us to shrink the particle size of processing of viscous or concentrated so- processing of bovine insulin yielded a existing drugs and make them better lutions, says Foster. product with geometrical particle-size suited for pulmonary delivery.” In the Arise process, a vessel con- distribution almost completely within Arise is a supercritical fluid (SCF) taining organic solution with dissolved the prescribed inhalation range of less precipitation process employing the en- pharmaceutical compounds is pressur- than 5 μm. 12 CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009
- 15. 15) (Continued from p. 11) C HEMENTATO R farmers to double crop yields. STORY NAME (Continued from p. 15) Pennycress contains 36% oil, twice that of soybeans, while an acre of pennycress can produce 115 gal of biodiesel Cellulose-to-aromatics process simplifies BTX production — more than twice that of soybeans. Growmark (Bloom- single-step method to convert cellulosic ing. Process benefits also derive from the fact A biomass into aromatic compounds offers a simpler and more environmentally friendly that no hydrogen or water is required, which eliminates a major waste stream present in ington, Ill.), a farmer-owned cooperative operating in the midwest U.S. and Canada, will route to the petrochemical feedstocks ben- biofuel processes like ethanol production. In purchase and market the biod- zene, toluene and xylenes (BTX), according addition, cellulosic starting material requires iesel produced by BMI. to a Massachusetts bioenergy startup com- no pre-treatment, Sudolsky adds. pany seeking to scale up the technique. The one-step catalytic fast-pyrolysis Mimicing moth eyes Based on a catalytic fast pyrolysis pro- process involves rapidly heating wood Researchers at the Savannah cess developed by University of Massachu- trimmings or other biomass to 600ºC in a River National Laboratory setts (Amherst, Mass.; www.umass.edu) re- fluidized bed reactor to form oxygenated (SRNL; Aiken, S.C.; www. searcher George Huber, the technique will compounds. Proprietary zeolite catalysts srnl.gov) are examining how generate BTX at costs lower than petroleum- convert the compounds into industrial special coatings that imitate derived BTX, says Anellotech (www.anello- chemical-grade BTX. structures found in nature can improve the performance of tech.com), the startup company formed by Anellotech is currently raising capital for solar cells, which typically lose Huber to commercialize the process. a pilot project to demonstrate the technol- about one third of the energy “It’s a more economical process” than petro- ogy beyond bench-scale. The pilot plant will due to reflection. Engineered leum-based aromatics preparation, explains process 1–3 ton/d of biomass. The company nanostructured coatings that Anellotech CEO David Sudolsky, in part be- expects to have a small-scale production fa- mimic the way moths’ eyes ab- cause the products need no further process- cility online in 2014. sorb light have been shown to reduce undesirable reflection from 30% to less than 2% on a Biobased succinic acid pilot effort underway typical solar cell, says SRNL. for polymer, solvent, food, pigment and phar- Durability testing of the coat- ilot-scale production of biobased suc- P cinic acid from dextrose has been dem- onstrated by Myriant Technologies (Quincy, maceutical applications. “We are not counting on any green premium to be competitive,” ings is underway to determine the feasibility of use in harsh environments, including heat, Mass., www.myriant.com). The firm expects says Sam McConnell, Myriant senior vice humidity and radiation. commercial production by mid-2010. president for Corporate Development. The succinic-acid process follows Myri- Biobased succinic acid is thought to avoid Electro-active polymers ant’s successful commercialization with some of the price volatility associated with Solvay Solexis SA (Bollate, partner Purac (Blair, Neb.; www.purac.com) petroleum-derived alternatives. The Myri- Italy; www.solvaysolexis.com) of a biobased D(–) lactic acid, which began ant process offers significant environmental has launched solvene, a range commercial production in June 2008. Suc- benefits, including lower greenhouse-gas of electro-active polymers for cinic acid process relies on an engineered E. emissions, McConnell explains, because the applications in printed elec- coli strain with deleted genes, and on off-the- process consumes carbon dioxide. tronics. The polymer exhibits shelf technologies for isolating products. Myriant Technologies is working to pro- a number of electro-active be- Myriant says its succinic acid production duce ton-sized samples that will be evalu- haviors, including: piezo elec- will be cost competitive relative to petroleum- ated by customers for purity and other (Continues on p. 14) derived alternatives such as maleic anhydride product specifications. Green honors acids and organic solvents, and re- quires less energy n June, the U.S. Environmental Pro- Atomic Transfer Radical Polymeriza- I tection Agancy (EPA; Washington, D.C.; www.epa.gov) announced the win- tion, for manufacturing polymers. The process uses sustainable reducing Corp. (Matthews, N.C.; www.cem. com), for a fast, automated process to ners of the 2009 Presidential Green agents, such as ascorbic acid, and re- analyze for proteins in food samples. Chemistry Challenge Awards. Winners quires less catalyst than alternatives The system can eliminate 5.5-million of the Challenge, which promotes R&D pounds of hazardous waste gener- of less hazardous alternatives to exist- Systems, Inc. (Madison, Wisc.; www. ated by traditional tesing in the U.S. ing technologies that reduce or elimi- virent.com), for its water-based Bio- each year nate waste in industrial production, are Forming process that catalytically - selected by an independent panel con- converts sugar, starch or cellulose into tor & Gamble Co. (Cincinnati, Ohio; vened by the American Chemical Soc. gasoline, biodiesel or jet fuel www.pg.com) and Cook Composites This year’s honorees include the follow- - ing (source, EPA): Mo.; www.ccponline.com), for Chempol www.eastman.com), for a solvent-free, MPS paint formulations, which use Matyjaszewski, Carnegie Mellon Uni- biocatalytic process for making esters biobased Sefose oils — made from versity (Pittsburgh, Pa.; www.cmu. (cosmetic and personal-care ingredi- sugar and vegetable oil — to replace (Continues on p. 19) edu), for an alternative process, called ents). The process avoids both strong petroleum-based solvents CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009 13
- 16. (Continued from p.13) C HEMENTATO R tricity, converting a mechanical stress into electricity or revers- ibly deforming in an electric field; pyro electricity, converting thermal energy into electrical energy; and ferro electricity, the Making SunCatchers instead of cars ability to switch its polarization. The polymer also has an intrin- tirling Energy Systems (SES; Phoenix, Compared to its predecessor, the new Sun- S Ariz.; www.stirlingenergy.com) and Tes- sera Solar (Houston; www.tesserasolar. Catcher: is about 5,000 lb lighter; is round instead of rectangular, which allows more sic high K constant, which is ad- vantageous for use in transistors and capacitors, says the firm. com) recently unveiled four, newly designed efficient use of steel; has improved optics; solar-power collection dishes at Sandia Na- consists of 60% fewer engine parts; and has HT heat-transfer fluid tional Laboratories’ National Solar Thermal fewer mirrors (40 instead of 80). The mir- Solvay Solexis (see story above) Test Facility (Albuquerque, N.M.). The re- rors are formed into parabolic shape using has also launched a new fam- fined design of SunCatchers will be used in stamped sheet metal, similar to the hood of ily of heat-transfer fluids — the commercial-scale deployment of the units in a car. “By utilizing the automotive supply Galden Ultra High Boilers. The 2010 (see also Solar’s Second Coming, CE, chain to manufacture the SunCatcher, we’re new fluid is said to feature the March, pp. 18–21). leveraging the talents of an industry that has highest boiling points among SunCatchers use mirrors attached to a refined high-volume production through an fluorinated fluids and a very low evaporation tendency. Applica- parabolic dish to focus sunlight onto a re- assembly line process,” says SES CEO Steve tion targets (in the temperature ceiver, which transmits the heat to a Stirling Cowman. More than 90% of the components range from 150 to 270°C) include Engine — a sealed system filled with hydro- will be manufactured in North America. photovoltaic-cell manufacturing, gen. As the H2 heats or cools, its pressure SES is planning the construction of a com- the solar-thermal industry, heat- rises and falls, driving a piston inside the mercial-scale reference plant later this year, ing fluids, and the metallurgical engine; this mechanical energy is used to and has a goal of producing 1,000 MW by and energy sectors. drive a generator for making electricity. the end of 2012. Printable batteries Printable batteries that can be An alternative to chlor-alkali produced cost effectively on a large scale have been developed arlier this year, NSR Technologies (Deca- branes and an electrical driving force to effect E tur, Ill.; www.nsr-tech.com) commercial- ized its patented process for producing po- the separation and rearrangement of the raw material into the acid and alkali products. by researchers at the Fraunhofer Institute for Electronic Nano Sys- tems (ENAS; www.enas.fraun- tassium hydroxide (45–50 wt.%) and dilute The requisite membranes are assembled in hofer.de), the Technical Univer- hydrochloric acid via a membrane separa- NSR’s proprietary IonSel cell stacks. sity of Chemnitz, and Menippos tions technology. The company’s flagship Additional processing steps, such as ion GmbH (all Chemnitz, Germany; production facility in Decatur, Ill. is the first exchange, chromatography and evaporative www.menippos.de). The battery commercial application of this process says concentration, are used as required to obtain is composed of different layers — Dr. Kris Mani, NSR’s president and CEO. products of commercial strength and purity. a zinc anode and a manganese NSR’s production process is more energy cathode, among others — and Current producers of commercial strength produced by a silk-screen print- KOH manufacture it via the chlor-alkali route. efficient than the chlor-alkali route, con- ing process. The non-recharge- NSR uses a membrane electrodialysis (ED) suming 40% fewer kilowatt-hours per ton of able batteries deliver 1.5 V, are process to convert salt to value-added chemi- caustic produced, says Mani. It does not in- less than 1-mm thick and weigh cals. Sodium chloride and potassium chloride volve the production or combustion of chlo- less than 1 g. Prototypes have are converted to the corresponding acid and rine gas, and allows production to occur from been made in the laboratory, and alkalis: HCl; and sodium hydroxide and KOH more compact plants located near end users. first commercial products could (caustic potash). The process, which occurs in NSR’s products are also free of oxidizing spe- be ready by year’s end. an aqueous medium, uses ion exchange mem- cies (hypochlorite and chlorate). Cleaner coal A replacement for Cr+6 Last month, Foster Wheeler AG (FW; Zug, Switzerland; www.fwc.com) commissioned culon, Inc. (San Diego, Calif.; www.acu- stainless steel, Ti and Al, says the firm. A lon.com) has developed a formulation of its proprietary SAMP technology (Self- SAMP technology can coat surfaces to im- part hydrophobicity, adhesion or corrosion the world’s largest circulating fluidized-bed steam generator, which is also the world’s first Assembled Monolayer of Phosphate) that inhibition. Such properties are achieved to incorporate the Benson ver- can be used as an alternative to hexavalent through covalent bonding between the SAMP tical-tube supercritical steam chromium used in primers and conversion and the material to which it is applied. The technology. Owned by Polish coatings to increase the adhesion of coatings phosphonate is a phosphorous acid that com- utility company Południowy to surfaces. The new SAMP formulation bines a reactive phosphonic acid “head” and Koncern Energetyczny SA, the can immediately benefit industries using a carbon-based “tail” connected by a stable CFB at Lagisza power plant Cr+6 as a spray-driven primer, with applica- C–P bond. The heads react with the surface produces 460 MWe of electric power at an efficiency that is tions such as golf club heads, electric circuit through metal-phosphorous bonds, and the “well above” that of typical coal boards and beverage cans — anywhere that tails stick out from the surface to provide plants, says FW. paint needs to adhere to and be durable on the desired chemical functionality. 14 CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009
- 17. Circle 13 onp. 54 or go to adlinks.che.com/23017-13
- 18. Technology Showcase MONITORING AIR EMISSIONS New requirements are spurring strong demand in air pollution monitoring Robert McIlvaine, McIlvaine Co. ubstantial technological ad- the measuring instruments. S vances to meet the growing regulatory scrutiny of a wide variety of pollutants have taken place over the past 50 years. In the last few years, the increased complexity One approach is to measure discrete particles and sulfur tri- oxide and then aggregate the two measurements. Another involves condensing the gas prior to mea- in regulations in developed countries surement. The one certainty is has been even more accelerated, chal- that the costs of both periodic and con- control, whereas instrument-based lenging the chemical process indus- tinuous measurements will increase. CEMS are used to control the amount tries (CPI) and their suppliers of air- of activated carbon injected into the monitoring equipment to reach new Mercury gas stream in order to maintain the heights. In addition, developing coun- Mercury now needs to be continuously required removal efficiency. tries are implementing their programs measured at U.S. power plants, which As mentioned, cement kilns in the for continuous air monitoring. Another have already spent $400 million in U.S. will also need to be equipped substantial trend is the monitoring of new continuous-emissions-monitor- with mercury monitors under pro- air pollutants as part of the optimi- ing systems (CEMS). However, the posed rules. In most developed coun- zation of the manufacturing process. vacature of the Clean Air Mercury tries, mercury needs to be measured This trio of developments will result Rule has eliminated the immediate at waste incineration plants. In Eu- in double-digit growth in the need for requirement for continuous measure- rope, waste incinerators and coal-fired air pollution monitoring in the next ment, except for local regulations that plants co-firing sewage sludge are re- several years. Some of the specifics of have their own rules. A new federal quired to limit mercury and to install these trends are outlined here. rule will be promulgated in the next mercury monitors. China has a mer- year or two in the U.S. It is anticipated cury program that is presently in the Fine particles that each plant will have to reduce research stage. It has been determined that fine par- mercury to a level below a stipulated ticles are more damaging to human weight per unit of flue gas. This will Air toxins health than larger ones. New regula- require continuous mercury monitors The U.S. now considers power plants tions in the U.S. require states to re- on all power plant stacks. Cement to be emitters of hazardous air pol- duce the quantity of fine particles in kilns and gold-mining operations will lutants, which will result in require- ambient air. The rule addresses par- also need to install monitors. ments to utilize maximum-achievable- ticles smaller in diameter than 2.5 mi- Two approaches to measurement control technology. The concern is the crons (PM2.5). The measurement for are considered acceptable. One is an large number of toxic pollutants emit- the regulation is made very difficult by instrument method. The other is with ted from coal-fired plants. the inclusion of condensable (vapors sorbent traps. These traps capture Table 1 shows the environmental that condense to droplets at ambient the mercury for a period of up to two burden from existing coal-fired plants. temperature) as well as discrete par- weeks and then are replaced by fresh The combination of nickel, selenium, ticles. Periodic measurement methods traps. The removed trap is then ana- barium, zinc, vanadium, hydrochloric are still under review. The fact that lyzed in a laboratory to determine the acid, sulfuric acid mist, hydrogen fluo- continuous measurement methods are weight of mercury captured during ride and ammonia is much higher in not clearly established creates both an the period. weight and equal in toxicity to the mer- opportunity and a problem for those The advantage of the trap method cury. In addition there are other metal trying to make the measurements, as is lower cost. The disadvantage is that toxins, such as arsenic, beryllium, lead, well as for the industry that supplies the trap cannot be used for process and cadmium, that are present in coal- 16 CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009
- 19. TABLE 1. U.S.AIR SOURCE ENVIRONMENTAL BURDEN Chemical Environ- U.S. Coal Other Coal Environ- New Fleet mental Emissions Industrial Environmen- mental Bur- of Coal Burden (1,000 tons) Sources tal Burden den Other Plants Index (1,000 tons) (1,000 tons) Sources Mercury 10,000,000 0.05 500,000 Nickel compounds 100,000 0.35 35,000 boiler sales will aver- Selenium compounds 100,000 0.215 21,500 age 70,000 MW. Barium compounds 10,000 0.215 21,500 A historic change is Zinc compounds 10,000 0.67 6,700 taking place in the Mid- Vanadium 10,000 0.615 6,150 dle East where huge in- compounds vestments in petrochem- Hydrochloric acid 1,000 267 267,000 ical plants are being Sulfuric acid 1,000 58 58,000 made. This will result in Hydrogen fluoride 1,000 28 28,000 very substantial markets both for air pollution Ammonia 1,000 2.3 2,300 CEMS and for process Air Toxics subtotal 35 946,150 500,000 100,000 analyzers for sulfur and PM 2.5 1,000 500 250 500,000 250,000 50,000 other acid gases. SO2 100 9,000 3,200 900,000 320,000 90,000 Waste-to-energy is the NOx 100 4,000 3,900 400,000 390,000 40,000 second largest market CO2 1 1,700,000 300,000 1,700,000 300,000 1,200,000 after power. This mar- TOTAL 4,446,150 1,760,000 1,480,000 ket will continue to grow throughout the world. plant flue gases but at Carbon dioxide The U.S. is well behind Europe and relatively low quantities. The EPA has classified CO2 as an air Asia in construction of waste-to-energy A number of new coal- pollutant. This means that ambient, plants. However, this situation is chang- fired plants are being periodic stack and continuous stack ing as the value of energy production constructed under per- monitoring will rise substantially. Ex- from this source is realized. mits that require them to meet very isting CEMS will, by and large, be used The use of stack CEMS in China low levels of specific pollutants, such for measurement, so the cost for new will grow rapidly. The CEMS market as cadmium and beryllium. The cost of hardware will not be very significant, in China will be the largest in the continuously monitoring each pollut- but those for services including analy- world after 2011. Within China, coal- ant would be prohibitive. The U.S. En- sis and stack testing will increase. fired boilers represent the biggest vironmental Protection Agency (EPA; The biggest increase will be the CEMS potential. SEPA (the Chinese Washington, D.C.) is therefore consid- need for ambient measurements. The equivalent of EPA) is cracking down ering using total particulate matter as models predicting various calamities on SO2 and NOx emissions from new a surrogate. need to be supported by actual peri- and existing power plants. The pro- Another approach is to use a odic or continuous measurement at posed steps include continuous report- multi-metal analyzer and calculate key locations in the water, ice, air, and ing of emissions, which will provide a the weighted toxicity or burden. In so on. In the air, there are big swings means for enforcement. Table 1, CO2 is rated with a burden in CO2 levels from season-to-season Overall, the world cost for stack and unit of 1. Vanadium is 10,000 times and locality-to-locality. ambient continuous monitoring plus more toxic and nickel is 100,000 times Instruments have been developed periodic monitoring and other related more toxic. Multi-metal analyzers are that can distinguish between CO2 services will rise to $2.2 billion in available at reasonable cost. that is anthropogenic (derived from 2010. This is a 20% increase over the If total particulate matter is used human activity) and that which is projected 2009 figures. The rapid ex- as a surrogate, the limits would likely naturally generated. Since 97% of the pansion in CO2 measurement invest- be lowered to reflect the need for toxin CO2 is currently generated by natural ment and the increased activity for reduction. It is agreed that the present sources, it will be important to iden- stack monitoring in Asia will account system of measuring opacity instead tify the anthropogenic segment. for most of the increase. These are of mass is too inaccurate to serve as the conclusions reached in the latest the basis for measuring the low par- Trends and financial impact update of the McIlvaine Air Pollution ticulate-matter levels associated with The future of air pollution monitoring Monitoring and Sampling World Mar- toxin reduction, therefore, mass moni- is tied closely to energy sources. If coal ket report. toring will likely be required. use were to be reduced, the market Edited by Dorothy Lozowski Mass monitoring is already required for CEMS would be significantly im- Author in Europe. In the U.S. it has been ap- pacted, negatively. However, the use of Robert McIlvaine has been plied to incinerators and to some coal is likely to increase, not decrease. producing market informa- power plants, which agreed to install World coal-fired-power-plant capacity tion reports for the environ- mental, energy, contamina- the devices as parts of settlements for will grow from 1,759,000 MW in 2010 tion control and process industries for over 30 years. air violations. This requirement for to 2,384,000 MW in 2020. Some 80,000 Visit his website at: www. mass monitors could generate costs of MW will be replaced, so there will be mcilvainecompany.com for more information. over $250 million in the U.S. during 705,000 MW of new coal-fired boil- the initial installation phase. ers built. The annual new coal-fired CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009 17
- 20. Invensys Newsfront TODAY’S SIS: INTEGRATED YET INDEPENDENT Bringing process control and instrumented safety systems together while still keeping them separate provides benefits beyond risk reduction y definition, integrated safety in- brand manager, with Emerson Processcess FIGURE 1. B strumented systems (SIS) have the potential to reduce risks. But recent advancement is also enabling the use of more sophisti- cated instruments and tools that can Control (Austin, Tex.). Or, if a processor has different haz- ard scenarios based on what step they are in a process, an ICSS allows them the flexibility to more aptly handle This image shows the Triconex Safety Instrumented System configuration from Invensys, with triple modular redundant controllers, input/output modules and communications subsystems benefit the process. For these reasons, those hazards. integrated control and safety systems which would include a Brand X con- (ICSS) are receiving recognition across Integrated, yet separate trol system and a Brand Y safety the chemical process industries (CPI). While this type of system is obviously system that work well together. In “There have been developments from designed to keep the process from this situation, the two systems share a technology point of view that allow going out of control while maintaining information via a gateway or third- the integration of process control and flexibility, there are many different party connection. safety systems, yet keep them sepa- ways to provide the integration and On the plus side, today’s interfaced rate enough so that they don’t compro- several different levels of integration. approach is better at data sharing mise safety, which was considered an In order for the integrated control and than the interfaced systems of the issue in the past,” says Kristian Ols- safety systems to reduce risks rather past, allowing the systems to provide son, Safety Center manager with ABB than increase them, experts stress the more information to operators, which (Norwalk, Conn.). “Keeping the sys- importance of implementing a system provides the opportunity to diagnose, tems separate enables the same risk that is “integrated, yet separate.” troubleshoot and prevent risky situa- reduction as would standalone sys- Several standards, among them IEC tions. For processors who are looking tems, while the integration provides 61508 and OSHA-endorsed ISA S84.01, for a system that has compatibility, many benefits for the process.” require that the control system shall but aren’t looking for a new control Among the benefits of more integra- be separate and independent from the system, the interfaced approach is a tion between process control and SIS safety related systems. This means good option. However, potential users for chemical processors is the flex- that the control and safety system need to keep in mind that while an in- ibility it provides. “Especially among should not share common hardware terfaced approach can share important our batch customers we see a lot of and configuration tools, for example, process information, it is somewhat interest in these integrated systems to eliminate common cause failures. limited in the amount of information because if they are running different The systems are integrated, though, and level of detail it can provide. types of products with different reci- when it comes to operator human in- For companies in need of more in- pes using a batch automation system terface or the sharing of non-safety formation or that are ready to replace to manage it all, they need a flexible, related information, according to Erik their control systems, automation safety instrumented system that is de Groot, global manager for safety companies can provide process con- able to adjust trip points based on the systems with Honeywell Process Solu- trol systems with integrated, yet in- hazards related to the different chemi- tions (Morristown, N.J.). dependent, safety instrumented sys- cals they are using,” says Mike Bou- The simplest way to achieve inte- tems. “The best of these systems are dreaux, safety instrumented systems gration is via an interfaced approach, integrated but separate, which means 18 CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009
- 21. ABB Figure 2. ABB’s High Integrity safety system, which is paired with its System 800xA for process control, is integrated but separate thanks to “embedded diversity,” which means the hardware and software architecture of the controllers is different to ensure that the failure modes of the safety system are completely unique from the potential failure modes of the process control system they are born from the same cloth shared components, provided there of the same infrastructure as the Ex- so they play well together, but are no concerns for functional safety. perion system or they can isolate the are still considered separate and ABB’s High Integrity safety sys- safety-related communication over a independent systems,” says Charles tem, which integrates with its System redundant, independent safety com- Fialkowski, national process safety 800xA for process control, is integrated munication network. “In either case, manager with Siemens Energy & Au- but separate thanks to “embedded di- the safety integrity level is guaran- tomation (Spring House, Pa.). “This versity,” according to Olsson. Here, in- teed,” notes de Groot. type of system doesn’t have any issues dependence in the performance of the as far as bringing the information to- safety system and the process control Pros and cons of integration gether in a common format and there’s system is achieved by implementing Benefits of integrated systems such no gateway or third-party device. Ev- diversity in the design of the control- as these are many. For example, many erything is done seamlessly.” lers. This means measurements have of the tools used for tracking, history, It is important not to confuse in- been taken in design, implementation and documentation and reporting of tegrated systems with what is often and testing within the hardware and information can be used by both the referred to as “common” systems. The software architecture of the controllers process control and safety systems. main differentiator between inte- to ensure that the failure modes of the “This gives end users benefits in their grated and common systems is that safety system are completely different every day work in terms of mainte- in common systems the same com- than the potential failure modes of the nance, engineering and record keep- ponents are used for process control process control system. “This is impor- ing,” notes Olsson. “Record keeping and safety whereas with integrated, tant because if a failure in the process and documentation are especially but independent systems, a complete control system causes a plant upset, helpful in the chemical processing in- physical separation of the safety in- we can be certain the safety system dustry where an audit trail is impor- strumented system and the process will take the proper measurements to tant. They can record when a certain control system is maintained. bring the process back to a safe state,” setpoint or operation was made or However, the way the separation is explains Olsson. changed in the system and by whom. maintained in an integrated system Honeywell handles the integrated Then if they need to track an incident varies from vendor to vendor. For in- but independent challenge in another or quality issue, they can find the in- stance, Emerson Process Control’s of- way. The company provides its Safety formation they need to do this.” fering, Delta V SIS, uses completely Manager safety system as part of the Asset management and predictive different hardware and software to overall Experion Process Knowledge maintenance tools also can be brought do the logic solving than is used in System. Safety Manager integrates from the process control world into the the process control system I/O (input/ seamlessly in the HMI (human-ma- safety realm to improve availability putput) and controllers. The Delta V chine interface) and allows peer-to- because users can ensure that equip- SIS has its own safety communication peer communication with the Expe- ment is maintained in an effort to pre- network, meaning it doesn’t share rion C300 process controller, although vent problems before there is a process the control network communications. the safety system is completely inde- upset or impact on production. It has completely different hardware pendent from the control system. In While the benefits are plentiful, with a completely different design the system architecture, the customer there are also a few risks. “When it from the process controllers, as well as has the option to select the level of in- comes to interoperable and integrated a different operating system. Despite tegration as it applies to the safety re- systems there are details that need to the physical separation, operations, lated communication between safety be examined like cyber security, which engineering and maintenance can use systems. They can choose to make use is the ability of the safety system to Chemical Engineering www.che.com AUGUST 2009 19 08_CHE_080109_NF2.indd 19 7/23/09 1:12:27 PM
- 22. Newsfront continue to functioneven if there is pletely separated from the safety sys- ment for operator training and also for a cyber or network attack,” says Joe tem’s ability to function.” testing the system to see how they in- Scalia, controls systems architect and Invensys’ Triconex system has this teract together. acting director of the safety business capability. If a plant owner wants to bring op- with Invensys Plc. (London, England). erators in for training on different ab- He notes previous instances where a Tools of the trade normal situations that might occur in processing facility has had a so-called Security risks aside, the increased use the process, it can be done offline. This worm or a disgruntled former employee of an ICSS is enabling the use of more simulation will provide operators with directly attack the system. “Unfortu- sophisticated tools, such as simula- exact experience via operator graphics nately the safety systems didn’t have tions and partial stroke testing. For and interactions so they can see what adequate security and were bypassed example, Invensys has an offering happens and learn how to handle an or turned off,” Scalia says. “Think about where immersive virtual-reality train- emergency shutdown situation or an the amount of risk for chemical proces- ing can be coupled with the simulators abnormal situation. “The whole expe- sors where most of what they use is from the process control system that rience for the operator is exactly what toxic or could cause an explosion.” works toward simulating a safe pro- they would experience online if they To get around this, Scalia stresses cess. This allows operators to move were actually running the chemical the importance of process control and through an environment and know process,” says Boudreaux. “There are a safety systems being able to share what the hazards are and what their lot of benefits to this, the biggest being data through integration or interop- responses should be without endan- that if they are familiar with abnor- erability, but that the safety system gering themselves. mal scenarios and know how they’ve must have its own link. “It polices that Similarly, Emerson offers offline reacted during the simulations, they link and has its own capabilities. If simulation tools for the process control can think more clearly and respond something happens to the communi- system that can be integrated with the more swiftly and appropriately during cations network, the communications safety instrumented system to provide a realtime situation.” function of the safety system is com- a complete offline simulation environ- Simulations can also be used for PEP PEPP 2009 P 20 0 9 18th Annual World Congress Polyethylene & Polypropylene Chain World Congress Zürich, Switzerland, October 13–14–15, 2009 Tuesday, October 13th Wednesday, October 14th Thursday, October 15th Polyolefins Global Review I High Pressure PE / EVA MBS (CH): Global PO Report MATT Management (NL): HP PE Technology Access Intelligence (USA): C2 Report LyondellBasell (DE): Lupotech*A Process Ineos (GB): HAOs Report United Initiators (DE): LDPE Peroxides Sinopec BRICI (PRC): PO Technology SRI Consulting (CH): LDPE/ EVA Markets Tasnee (KSA): New Global PO Player OPEN HOUSE EVENT Thursday morning Polyolefins Global Review II PE/PP Process Technology Oriental PC (EG): PO Challenges Chevron Phillips (USA): Process Technology by: Nova Chemicals (USA): Processes/Catalysis Ineos (FR): Dual PE Technology Omya International AG Ineos (BE): HDPE Products Lummus Novolen (DE): Novolen* Technology (Oftringen, Switzerland) Borealis (AT): PP Pkg. Solutions Univation (USA): Unipol* PE Process Vogt Plastic (DE): PO Recyclates Polyolefins Logistics Polyolefin Catalyst Update Invited Panelists (Global Review Sessions) Zeppelin (DE): PO Logistics Chain Akzo Nobel (NL): Aluminoxane Grades Haver & Boecker (DE): Packaging/Distrib. Albemarle (USA): Polyolefin Catalysts Interbulk (NL): Suppy Chain Mgmt. Lummus Novolen (DE): Catalysts Solutions Converters: K. Schmidt/Agility (DE): Logistic Trends PQ Corporation (GB): Silica Catalyst Manuli Stretch PE/PP Engineering Technology PE / PP Additivation / Modifications Schöller Arca Tetra Pak International Tecnimont (IT): Servicing PO Ind. Songwon (CH): TNPP Replacement Coperion (DE): PP / PE High Cap. Lines Chemtura (BE): Additives for Efficiency K-Tron (CH): Mixing / Dosing Milliken (BE): Speciality Additives Brand Owners: Omya (CH): Mineral Modifiers Johnson & Johnson Evening Hospitality Function Procter & Gamble Unilever M AACK B USINESS S ERVICES Maack & Scheidl Partnership PLASTICS TECHNOLOGY AND MARKETING CH- 8804 Au / near Zürich, Switzerland Tel: +41-44-781 30 40 Fax: +41-44-781 15 69 GLOBAL CONFERENCES, STUDIES, PROJECTS E-mail: MBSpolymer@bluewin.ch www.MBSpolymer.com Circle 23 on p. 54 or go to adlinks.che.com/23017-23 20 CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009
- 23. SAFETY INSTRUMENTED SYSTEMPROVIDERS ABB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .www.abb.com Emerson Process Management . . . . . . . . . . . . . . . . . . . . . www.emersonprocess.com Honeywell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . www.honeywell.com Invensys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . www.invensys.com partial stroke testing is performed. Rockwell Automation . . . . . . . . . . . . . . . . . . . . . . . . . www.rockwellautomation.com Partial stroke testing also provides in- Siemens Energy & Automation . . . . . . . . . . . . . . . . . . . . www.siemens.com/process formation and data about valves and Yokogawa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . www.yokogawa.com process behaviors, as well as allowing predictive maintenance, if needed. testing changes that were made to the offline for testing periodically. More When the safety and process ben- safety instrumented system. For in- recently, according to Art Pietrzyk, efits are spelled out and coupled with stance, if an engineer wants to change critical process control and safety the ability to use more sophisticated, a trip point or the logic in the safety segment manager with Rockwell Au- process- and safety-enhancing tools, system module, they can first make tomation (Milwaukee, Wis.), there’s integrated safety and control makes that change in an offline environment a trend toward using safety-certified sense, especially in an economy when and run a full functional test. It will instrumentation and safety-certified processes are running for longer peri- operate just as it would in a physical valves and algorithms that work with ods of time between turnarounds. “It is logic solver. “That saves some engi- the valves to perform partial stroke important that the process and safety neering costs, and because it provides valve testing. “They put positional systems controlling the compressors, the ability to test every scenario of- and sensing devices on the valve and turbines and other critical equipment fline, tests can be done much more rig- move it to a partial opening to make are available to generate money and orously,” explains Boudreaux. sure it’s still responding and that the ensure that the plant continues to run Integration is also permitting the safety integrity of the valves is in in a safe manner,” says Scalia. “The use of intelligent device communica- order,” says Pietrzyk. bonus is that users are getting ad- tion with partial stroke testing. In Generally this type of testing helps ditional functionalities, such as com- the past, there were multiple valves extend proof test intervals to ensure municating with intelligent devices on the safety system to serve as back a valve’s safety integrity is where it so they can more effectively maintain up in the event of failure of the valve. should be. Users of the technology do and optimize their operations.” ■ Typically these valves had to be taken not have to do proof tests as often if Joy LePree Circle 14 on p. 54 or go to adlinks.che.com/23017-14 CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009 21
- 24. Circle 15 onp. 54 or go to adlinks.che.com/23017-15
- 25. Adsorption Department Editor: Kate Torzewski NOMENCLATURE uccessful adsorber design requires S information about certain adsorbent properties, including: adsorbent densi- ties and void fractions; isotherms or other βij = 1+ 1−ε ε 1−ε Aj A B C Henry’s law coefficient empirical coefficient Concentration (subscripts: 0, initial; equilibrium data; and data on mass-transfer 1+ Ai (7) f, final; i, instantaneous) kinetics and fixed-bed dynamics. Here, ε dp particle diameter these adsorbent properties are explained, DAB adsorbate diffusivity in the liquid along with corresponding equations. KINETICS DATA Deff effective diffusivity DENSITIES AND VOID FRACTIONS Kinetics data describe the intraparticle F fractional conversion mass-transfer resistance and control the i assigned to strongly adsorbed com- Three densities are relevant: bulk, particle cycle time of a fixed-bed adsorption ponent and solid. There are four pertinent void frac- process. Fast kinetics, or a high rate of j assigned to less strongly adsorbed tions, three corresponding to the three den- diffusion, occur when the effluent concen- component sities, and one representing the overall void tration remains level until the adsorbent is jD Colburn-Chilton j-factor fraction in the bed of adsorbent (ε). These almost saturated, then rises sharply. Slow k fluid-to-particle mass transfer coeffi- terms are related in the following way: kinetics, on the other hand, occur when the cient effluent concentration begins fluctuating ρ B = (1 − ε B ) ρ P = (1 − ε B ) (1 − ε P ) ρ S soon after adsorption starts. The effect of l particle radius (for a sphere or cyl- inder), or half-thickness (for a rect- = (1 − ε ) ρ S (1) slow diffusion can be overcome by add- angular solid) ing adsorbent at the product end, or by L bed length Bulk density is the mass of adsorbent in a increasing the cycle time. It is also possible given volume. Particle density is the mass to use small particles. n* adsorbent loading of adsorbent per volume occupied by the Intraparticle diffusion is characterized Re Reynolds number particle. Solid density is the mass of the by an effective diffusivity Deff, which equals Sc Schmidt number adsorbent per volume occupied by the par- DABερ/τ. Dimensionless time is expressed t elapsed time ticle, but with the pores’ volume deducted. as Deff t/l 2, which allows the determination xi mole fraction in fluid phase of the fractional change (during adsorption yi mole fraction in adsorbed phase EQUILIBRIUM DATA or regeneration), as shown below. α selectivity, 1<α<infinity Adsorption-equilibrium data are usually β selectivity, 0<β<1 gathered at a fixed temperature and plot- ε void fraction (subscripts: B, bulk; P, ted or tabulated as isotherms: adsorbent particle; S, solid) capacity (loading) versus fluid-phase μ fluid viscosity concentration (or partial pressure, for gases ρ fluid density (subscripts: B, bulk; P, and vapors). Below are three equilibrium (8) particle; S, solid) equations for isotherm data. τ tortuosity Henry’s Law: This equation shows that, when searching υs superficial velocity for an effective adsorbent, it is usually safe ψ particle shape factor n* = AC (2) to choose one having a large diffusivity, a small diameter, or both. The particle shape factor, ψ, is 1.0 for Langmuir Isotherm: beads, 0.91 for pellets and 0.86 for flakes. AC FIXED-BED DYNAMICS αi is the ratio of particle interfacial area to n* = (3) 1 + BC volume, which equals 6(1 – ε)dP. Interstitial mass transfer in fixed beds, Another major factor in bed dynamics is primarily fluid-to-particle transfer, can be pressure drop. Most adsorbers are designed Freundlich Isotherm: related to the fluid, adsorbent and system to operate with relatively low pressure drop, properties via either of two equations, n* = AC B because large particles are used whenever (4) depending on the value of the system’s possible and the velocity is typically low, Reynolds number. to allow equilibration of the fluid with the Henry’s Law is the simplest isotherm, adsorbent. The pressure drop in a fixed bed while the Langmuir Isotherm takes surface (9) is represented by the Ergun Equation, below. coverage into account, and the Freundlich Isotherm is the result of fitting isotherm data For 10<Re<2,500, use Equation (10), to a linear equation on log-log coordinates. where Sc equals μ/ρDAB. ΔP ⎛ 1 − εB ⎞⎛ ρυ 2 1 − ε B ⎞ s In situations that involve multiple adsor- = ⎜150 + 175⎟⎜ ⎜ 3 ⎟ ⎟ bate components in the feed, the concept L ⎝ Re ⎠⎝ gc dp ε B ⎠ jD = ( k υs ) Sc0.667 = 1.17 Re−0.415 of selectivity comes into play. Selectivity, α (10) (12) and β in the three equations below, is the References ratio of the capacity of an adsorbent for For lower flowrates, corresponding to 1. Knaebel, K., The Basics of Adsorber Design, one component to its capacity for another. values of a modified Reynolds number, Re’, Chem. Eng., April 1999, pp. 92–101. of below 50, use Equation (11). yi y j 2. Knaebel, K., For Your Next Separation, α ij = Consider Adsorption, Chem. Eng., November xi x j (5) jD = 0.91ψ Re'−0.51 (11) 1995, pp. 99–102. 3. Masel, R.I., “Principles of Adsorption and Reac- α ij = Ai A j (6) (11a) tion on Solid Surfaces,” Wiley-Interscience, New York, 1996.
- 26. People WHO’S WHO Brandmeier Mueller Shott Hook Lee Michael Brandmeier becomes senior president of the Compressed Air and Veolia Water Solutions & Tech- vice-president of Toray Plastics Gas Institute (Cleveland, Ohio). nologies (Birmingham, U.K.) names (America) Inc. (North Kingstown, Stuart Lee director of engineered R.I.) and joins its board of directors. Nick Phillips becomes global business solutions, and Bob Hook general man- development director of Clariant Oil ager of design & build. Codexis, Inc. (Redwood City, Calif.) Services (Charlotte, N.C.). promotes David Anton to senior vice- WIKA Instrument Corp. president, research and development, Pieter Schoehuijs becomes chief (Lawrenceville, Ga.) promotes and John Grate to senior vice- information officer for AkzoNobel James Zielinski to director of president, science and innovation, NV (Amsterdam). customer operations. and chief science officer. Ian Shott, CEO of Excelsyn Ltd. Bill Harvey becomes the director of Frank Mueller, president of Kaeser (Newcastle, U.K.) becomes president logistics engineering for ChemLogix Compressors , Inc. (Fredericksburg, of the Institution of Chemical Engi- LLC (Blue Bell, Pa.). Va.) is named to a two-year term as neers (IChemE; London). Suzanne Shelley NOW MORE THAN EVER ONLY WEFTEC delivers the top educational program ■ ■ ■ is the largest annual water and wastewater exhibition in the world consistently draws a strong audience from around the world helps you stay strong in an uncertain economy offers you the world’s leading technology 09 For full conference details, please view the online planner at http://weftec2009.expoplanner.com The one—and only—place where you get it all. www.wef.org Circle 16 on p. 54 or go to adlinks.che.com/23017-16 24 CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009
- 27. Mettler Toledo Metso Hoerbiger Kompressortechnik Holding Coriolis meters for develo developed to enable high-frequency low-flow applications an I/O and digital signal processing. — The Micro Motion Elite Corio- Mets Metso Corp., Automation business lis meter range (photo) has been en lin line, Helsinki, Finland expanded for low-flow applications.tions. w www.metso.com Available in two sizes (2 and 4 mm m nominal dia.), the new meters de- e- A optimum valve for An h liver flowrates of 2 to 330 kg/h with rec reciprocating pumps accuracies of ±0.05% (liquid flow),low), C The CL pump valve (photo) for recip- ±0.35% (gas flow), and ±0.0000 g/mL rocati rocating pumps combines the two key re (liquid density). Wetted parts are of Emerson Process factor factors for cutting operating costs in Management 316L stainless steel and the sensorensor va one valve: optimum performance and enclosure is available with a polished surement with a full-fledged ion mode. efficient service. The CL pump valve 316L external surface and rounded The multi-parameter SG68 covers the has an optimized design and a combi- corners. For corrosive and high-pres- measures pH/ion/dissolved oxygen. nation of proven materials. They can sure applications, the meters are also Handy features like automatic air- be incorporated into any reciprocating available in nickel alloy construction pressure compensation, helpful ion pump and are suitable for use with and are rated to 413 bar. — Emerson mode, and a wireless infrared commu- any aqueous solution. The valve fea- Process Management, Hatfield, Pa. nication port, save time and guaran- tures heavy duty, non-metallic sealing www.emersonprocess.com tee correct results. — Mettler Toledo, elements, springs that do not come in Columbus, Ohio contact with the medium being han- Test pH, conductivity, dissolved www.mt.com dled, and optimized flow control. — oxygen and ion concentrations Hoerbiger Kompressortechnik Holding These multi-parameter portable me- Condition monitoring & analysis GmbH, Vienna, Austria ters (photo) measure pH, conductivity, integrated in automation system www.hoerbiger.com dissolved-oxygen and ion concentra- This company has integrated machin- tion. All three instruments are based ery condition-analysis technology into This range of flowmeters and on the rugged design of SevenGo, and the metsoDNA CR automation sys- controllers is now more flexible are watertight according to IP67. The tem. The application, called DNAma- The Smart-Trak 2 (photo, p. 24D-2) three new meters expand the range chineAssessor, enables maintenance is a significant redesign of this firm’s of portable instruments and offer in- staff to have first-hand access to ma- flagship Series 100 Digital Mass Flow novative Intelligent Sensor Manage- chine vibration data and mechanical Meters and Controllers. Among the ment. The SG23 is a robust, dual- component condition analysis through expanded functionality of Smart-Trak channel pH/conductivity meter for the same user interface (photo), which 2 is true linear performance, which routine work. The professional pH/ion/ is used to measure and control the provides high accuracy and great flex- conductivity meter SG78 combines all process and product quality. New met- ibility in multiple gases. With Dial-A- functions of pH and conductivity mea- soDNA CR system features have been Gas Technology, users select from up Note: For more information, circle the 3-digit number CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009 24D-1 on p. 54, or use the website designation.
- 28. Moyno New Products toten pre-programmed gases, or sub- stitute their own. Smart-Trak 2 also provides the ability to adjust calibra- tion in the field for each of these ten gases independently. It provides the most advanced linear sensor avail- able, smoother valve performance, more robust electronics and more con- trol over a wide range of functions, ac- Sierra Instruments cording to the firm. The Compod, has also been introduced as a Smart-Trak 2 add-on, which expands networking, streamlines and simplifies functional- ity, and reduces costs. — Sierra Instru- ments, Monterey, Calif. www.sierrainstruments.com This pump provides precise control in low-flow applications The Chemical Metering Pump (photo) offers economical and efficient perfor- mance when metering low-flow liquids in a wide range of processing applica- tions, including dosing, sampling and metering. The progressing cavity de- sign of the pump results in a smooth flow, free from pulsations and varia- tions in velocity and volume, which prevents material waste or mixture imbalance. The pump features sealed universal joints for longer life, and has no valves to clog, stick or vapor lock. The unit provides pressures to 300 psi and flowrates from 1 to 190 gal/h. The pump is available in bare-shaft, close- coupled, and motorized configurations. — Moyno, Inc., Springfield, Ohio www.moyno.com An aseptic valve for critical areas This patented, compact aseptic control valve (photo, p. 24D-3) newly added to the Badger Meter valve range, is suit- able for use in critical areas, such as bioreactors pharmaceuticals, biolog- ics and food processing. The Series SCV-09 is a modulating diaphragm style valve that meets the manu- facturing standards of 3A Sanitary Standards. The valve uses a patented sealing arrangement, which avoids metal-to-metal contact that could re- Circle 20 on p. 54 or go to adlinks.che.com/23017-20 24D-2 CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009
- 29. HF Inverting Filter Centrifuge Cutting edge centrifuge technology for filtration, washing and drying of solid/liquid suspensions GEA Niro Pump Engineering a co-current two-fluid nozzle for at- omization. A single-point powder dis- charge makes product collection easy, and the standard cyclone secures an efficient product recovery. A cartridge filter is available (optional) for clean- ing the exhaust gas to reduce emis- sions to a minimum. — GEA Niro A/S, Søborg, Denmark www.niro.com Advanced technology Download CAD drawings for simultaneous for free multi-function Colder Products This company is complementing its drying and mixing sult in metal particles being released comprehensive product database with into sensitive products, while provid- an easy-to-use download tool for two- ing a similar level of control to a metal and three-dimensional CAD draw- plug and seat. The valve is available ings. The software enables users to in sizes 1/2, 3/4 and 1 in. with body generate and download CAD files for of 316L stainless steel. It is suitable sensor, fieldbus, interface and con- for low to medium flowrates and has nectivity products free of charge and a maximum operating pressure of 10 without registration. System-specific bar. — Pump Engineering Ltd., Little- and cross-system formats are possible hampton, U.K. for technical documentation purposes www.pumpeng.co.uk or 3D models for more complex Solid- Pennwalt works applications. — Turck, Inc, Min- Super-D-Canter A new spray dryer neapolis, Minn. Cutting edge continuous for laboratories www.turck.com centrifuge technology The MobileMinor Basic spray dryer for separation of slurries into liquid or (photo) is said to meet all the basic For clean applications, solid phases. requirements of laboratories, espe- use this metal-free cially those in small companies and The all-plastic DrumQuik PUR universities, and other laboratories chemical-dispensing system (photo) that don’t need many of the options provides extraction of high-purity available for the advanced MobileMi- chemicals from drums, jerry cans and nor models. The MobileMinor Basic intermediate bulk containers. The sys- meets all health and safety require- tem is comprised of a PVDF coupler ments, including dust explosion haz- and an HDPE drum insert assembly. ard (class ST1), and is easy to operate. The drum insert assembly contains The system is suitable for laboratories a bung closure and dip-tube and can that need only basic facilities for dry- be shipped as part of a drum package, ing food and chemical products. It is providing a cost-efficient alternative supplied with a push-button control to open and semi-open dispensing sys- panel and either a rotary atomizer or tems. The coupler features a built-in Circle 19 on p. 54 or go to adlinks.che.com/23017-19
- 30. New Products vent port,which allows connection fully automate the creation of of a check valve to prevent release of CLP-compliant labels and SDS harmful vapors to the atmosphere or documentation. The deadlines of an inert blanket gas (N2 or CO2) to December 1, 2010 for substance clas- protect valuable chemicals from expo- sification and June 1, 2015 for mix- sure to air. DrumQuik PUR is made tures provide little time for full CLP from FDA-approved, animal-free and compliance, but the delivery of IA 4.1 Omega Engineering RoHS-compliant materials that are SP2 facilitates this process for manu- compatible with high-purity chemical facturers that may otherwise struggle handling processes found in semicon- to meet these deadlines. Being at the ductor, flat panel and pharmaceutical forefront of changing regulations, this a mating receiver up to 90 m away. manufacturing. — Colder Products firm will continue to track the GHS Each unit is factory set as a Type J, Co., St. Paul, Minn. schedule and will add support as addi- K, T, E, R, S, B, C or N calibration con- www.colder.com tional countries announce their adop- nector. When activated, the connector tion plans. — Atrion International, St. will transmit readings continuously Support EU regulations for clas- Laurent, Quebec, Canada at a preset time interval that was pro- sification, labeling and packaging www.atrionintl.com grammed by the user. Each unit mea- Intelligent Authoring’s (IA) Service sures and transmits: TC input reading Pack 2 (SP2) is now available, with A thermocouple connector that and connector ambient temperature support for the EU’s new Regulation communicates wirelessly to a receiver and is displayed on the on Classification, Labeling and Pack- The MWCT Wireless Smart Thermo- PC screen in real time using free soft- aging (CLP) of substances and mix- couple Connector Series (photo) fea- ware. — Omega Engineering, Inc., tures. This solution now provides Man- tures stand-alone, battery-powered Stamford, Conn. aged Regulatory Content in support of thermocouple (TC) connectors that www.omega.com the new regulation, enabling users to transmit measurement data back to Kate Torzewski Circle 21 on p. 54 or go to adlinks.che.com/23017-21 Circle 22 on p. 54 or go to adlinks.che.com/23017-22 24D-4 CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009
- 31. Circle 17 onp. 54 or go to adlinks.che.com/23017-17
- 32. Pressure F Impact Cover Story Feature Report a b c Fine Grinding F a F With Impact Mills FIGURE 1. Fragmenta- tion of glass beads is achieved by either impact or pressure (F = force; a = contact area; b = cracks; c = fines) A primer on which mill to use B Breakage for various types of products Bodo Furchner, Hosokawa Alpine AG Stress any branches of the chemi- applied stress and the fracture occurs M cal process industries (CPI) make use of impact commi- nution to process solid mat- ter, such as minerals, foodstuffs, phar- maceutical products, and above all, suddenly (Figure 2). The dark area under the plotted line is equivalent to the work that is necessary to deform the particle. With impact comminu- tion, the kinetic energy of the particles products for the chemicals industry. is employed to generate the requisite Impact comminution is also used for degree of deformation. In the linear B Elongation coarse crushing, but the focus of this range, the deformation is elastic and article is fine grinding with end-prod- reversible. As soon as higher stresses FIGURE 2. This stress-strain curve uct particle sizes below 500 μm. The occur, the material strength is exceeded shows the behavior of brittle-elastic technology of impact comminution is, locally and cracks are triggered. The materials however, not particularly popular with cracks grow extremely quickly and the users of impact grinding systems lead to destruction of the particle. gas is expanded in Laval nozzles. At because it is energy-intensive, as- Equipment has been built for sci- common gas pressures and tempera- sociated with a high noise level and entific experiments in which indi- tures, the exit velocity of the gas jets frequently also gives rise to time-con- vidual particles are subjected to one is around 500 m/s. suming maintenance work. In spite of single impact under defined condi- As Figure 1 shows, a single fracture this, impact comminution is still the tions. From these single-particle im- event leads to a number of coarse frag- most cost-effective solution in many pact tests the following three things ments but to relatively little fine prod- processing operations. are known: that a minimum fracture uct. Because of this, the aim is mul- energy must be applied to the parti- tiple stressing of the particles in mills The fundamentals cles, that the probability of fracture is in order to obtain a fine end product. With every method of comminution, dependent on the kinetic energy and One can assume that a feed mate- one has to generate a level of stress that the resultant particle-size distri- rial is subjected to between 5 and 20 in the particles that is so high that bution is dependent on the properties impact events in simple rotor impact the particles fracture as a result. Be- of the material being processed. mills. With fine grinding, air classifiers side other methods, this stress can be According to theory, a speed multi- can be integrated into mills that allow generated by pressure (compression) plication of 5.6 would be necessary to only those particles with the desired or impact (Figure 1). In the case of double the stress in the particles. In end-particle size to pass through the compression, the particle is stressed other words, increasing the impact classifying wheel, but which return between two solid elements, whereas speed has only a limited influence on coarser particles for final grinding. For in the case of impact comminution, the expected fineness. On the other jet mills, up to 100 stressing events can the particle is in contact with only hand, the impact speed is the only be necessary to grind the feed material one other element at the moment of parameter with which it is possible to to high fineness values if it is of poor fracture, either an impact plate or an- effectively change the stress condition grindability. The number of stressing other particle. in a particle, which is why impact mills events is therefore a parameter that A prerequisite for impact comminu- usually run at high peripheral speeds has a greater influence on the product tion is brittle-elastic material behav- of up to 150 m/s. When two rotors are fineness than the stressing speed. ior. Materials scientists call a material driven to rotate in opposite directions, The particle size distribution of the brittle-elastic if deformation of the relative speeds of up to 250 m/s can ground product is a function of the mill sample is initially proportional to the be achieved. In jet mills, compressed parameters, stressing frequency and 26 CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009
- 33. TABLE 1. MOHS' SCALE OF HARDNESS 1 Talc 2 Gypsum 3 Calcite 4 Fluorite 5 Apatite 6 Orthoclase 7 Quartz 8 Topaz 9 Corundum b) a) c) 10 Diamond FIGURE 3. Simple rotor impact mills with crushing rotor and sieve (a), with plate beater unit and grinding track (b) and with pin discs (c) stressing intensity, as well as the feed and mills and systems heat up to case the product is fed centrally and material characteristics. Today it is not 50–60°C under full load. Heat-sensi- the feed material migrates in ra- possible to accurately predict the result tive products can be processed only by dial direction across the disc, just as of a comminution trial with an impact cooling the feed material or the mill with the pin mill. The grinding zone mill based on scientific principles. This air, or both, which ultimately means can also be cylindrical, in which case applies to particle size distributions additional energy costs. the feed material migrates along the and to the specific grinding energy. Liquid components in the feed ma- cylindrical surface through the mill. terial can also have an extremely dis- The transport of the material can take Feed material requirements ruptive effect. The product should be place against the force of gravity, in If impact comminution is to be eco- dry, with the maximum moisture con- the direction of the force of gravity, or nomically viable, the feed material tent of normally only a few percent. If even at right angles to it. In addition, must fulfill a number of general re- liquid is released during comminution, impact mills can be equipped with a quirements. In the case of fine impact this frequently leads to the formation classifying discharge, for example mills, there is a maximum feed size of build-up. This also applies to feed sieves, screens or classifying wheels. that must not be exceeded if the mill material that contains oil or fat. The design most suitable for a given is to remain undamaged by any large Besides the specifications related to application must be determined dur- lumps in view of the high peripheral the particle size distribution, the prod- ing the course of trials. speed. A particle size of 5 to 10 mm uct properties mentioned here play a Classic rotor impact mill. These can be assumed as the maximum, major role in the selection and design machines are characterized by a flat- whereby the faster the rotor rotates, of impact mills. For this reason, trials cylindrical, vertically upright housing the finer the feed material should are always carried out with a test sys- and a horizontal shaft supporting the be. Tramp material must be removed tem for new applications. rotor (Figure 3). These machines have from the feed material. a big door, which can be easily opened Mechanical impact grinding can be Machine types for fine grinding for maintenance of the grinding equip- used on materials with a Mohs’ hard- Rotor impact mills have been in use ment. The product is fed to the center ness of up to 3–4 (see Table 1). But for over 100 years. As a result of the of the rotor and exits in ground con- even small amounts of harder compo- wide range of feed products, a great dition at the periphery of the mill. nents in the feed material can lead to number of different machine types Air flowing through the mill assists an uneconomical degree of wear. When have established themselves on the transport of the product and cools the grinding natural gypsum — which is market during this time. Jet mills, machine and product. The high-speed actually soft — a few percent of quartz which operate with a gaseous me- rotor with impact elements grinds the in the feed will make it necessary to dium, have also been on the market feed material and assists the trans- exchange the wear plates in the mill for a long time. In this article, only a port of the air, in a similar way to a frequently. The same or similar phe- few of the widely available machine radial fan. The fineness is set as a nomenon applies to vegetable prod- types can be described. function of the rotor speed and the ucts that are contaminated with sand. Mechanical impact mills. Simple product throughput. Higher through- In the case of especially fine feed ma- impact mills consist essentially of a puts lead to a coarser product, which terials, harder materials can also be high-speed rotor. Fine particles fol- is attributed to increasingly ineffec- processed, provided that the wear pro- low the flow of air in the mill after tive particle-particle impacts. The feed tection in the mill is well adapted to extremely short acceleration paths. metering unit is controlled by the cur- the product properties. Because of this, the clearance between rent loading of the mill motor. The feed material should not be rotating and stationary grinding ele- Sieve inserts with various kinds heat-sensitive, that is, the softening ments should only be a few millime- and arrangement of perforations have or melting point has to be above 70°C ters. Characteristic for fine impact the benefit of top-size control, but are if the material is to be ground in a mills are a high-speed rotor and sta- always more prone to wear. Sieves can mechanical impact mill. The reason is tionary grinding elements located in only be employed down to a minimum that the energy of the motor is con- its immediate proximity. The grind- aperture size of approximately 0.5 verted almost completely into heat, ing zone can be disc-shaped, in which mm. The design shown in Figure 3a is CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009 27
- 34. TABLE 2. APPLICATIONSFOR SIMPLE ROTOR IMPACT MILLS Pharma/Food Chemicals Minerals Other Cover Story Sugar Fertilizer Natural gypsum Wood shavings Lactose Paint FGD-gypsum Cork Casein Pigments Limestone Fodder therefore suitable for coarser grinding Herbal tea Salts Chalk Recycling tasks. In the fine range and with coarse Starch Silicates Used paper feed materials, grinding tracks are Gelatine Wax Tobacco used. Grinding tracks usually have an annular discharge gap for the ground Spices Resin product. In the case of the plate beater Hibiscus Stearate unit (Figure 3b), exchangeable impact Sage Sulfates plates permit the processing of mildly abrasive materials. At high speeds and Rose hips Phosphates low throughputs and in combination Active pharmaceutical Plastics with a grinding track, fine products ingredients (API) Cellulose are achieved. When employed in com- derivatives bination with a grinding track or sieve ring, or both, the plate beater unit is FIGURE 4. FIGURE 5. In long gap mills, the rotor is A pin mill vertically arranged suitable for fine grinding, defibration, with two chipping and deglomeration. rotating pin With pin discs (Figure 3c), commi- discs nution takes place between the rotat- Air + ground ing and stationary concentric rows of product pins. The diameter of the pins and the pitch diameter for the pins are geared to each other such that particles cannot flood through the pin rows. The fine- Air + feed ness is regulated as a function of the product speed. The principle of multiple stress- ing is implemented in this mill in an extremely graphic manner: the par- ticles have to pass through every row TABLE 3. APPLICATIONS FOR PIN MILLS WITH TWO ROTORS of pins before they are able to exit the mill and impact against many pins in Pharma/Food Chemicals Minerals Other the grinding process. The narrow gap Spices (cryogenic Paints Chalk Proteins between the rows of pins ensures high grinding) Pigments Limestone Rubber impact speeds, even for fine particles. Cacao press Stearate Coating of (cryogenic cakes Plastics (cryogenic grinding) limestone grinding) Tramp material in the feed material is a risk to the relatively fragile pins and can cause a lot of damage. or co-rotating pin discs. The relative is vertically arranged (Figure 5). The The largest mills of this type have speed of the outside row of pins can feed material is charged from below, rotor diameters of some 1.5 m and a reach up to 250 m/s. Compared with entrained in the transport air and is drive power of up to 315 kW. The max- the simple, fine impact mill, the coun- conveyed pneumatically through the imum peripheral speeds reach 150 ter-rotating pin mill achieves signifi- grinding zone, but can also be fed to m/s. The maximum fineness that can cantly higher fineness. the lower area of the grinding zone. be expected for simple impact mills The use of two rotating discs re- The grinding zone extends over the is, for many products, around 100 μm. duces the formation of deposits on entire cylindrical area between the When reference is made in this article the pins in comparison with pin mills rotor beaters and the peripheral grind- to the product fineness but is other- equipped with one stationary disc ing track. The product must travel all wise not specified, this is understood or mills with grinding tracks. This the way along this gap, which is lon- as the cumulative undersize of the can be accomplished by a generously ger compared with other mills. Mills particle size distribution of 97%. Table dimensioned housing, the so-called of this type are therefore called long 2 shows some applications for simple wide-chamber housing. Therefore, gap mills, although the name air vor- impact mills. this machine is especially suitable for tex mill is also known. This name, Pin mills with two rotating pin the grinding of sticky feed material. however, implies that comminution is discs (disintegrators). The basic Applications for this machine type are the result of particle-particle impacts design of this machine corresponds to given in Table 3. The largest pin mill in an air vortex. Because an efficient that of the classic, fine impact mill, al- of this type ever to be built has a pin fine-grinding operation necessitates though here, both pin discs are driven disc diameter of approximately 1.1 m unhindered impact of the particles separately (Figure 4). The fineness of and a drive power of 500 kW. on the grinding elements of the mill, the end product is set as a function of Long gap mills. In contrast to the grinding in air vortices can only be a the peripheral speeds of the counter- classic, fine impact mill, the rotor here minor effect. The fineness in this mill 28 CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009
- 35. TABLE 4: APPLICATIONSFOR THE LONG GAP MILL Food Chemicals Minerals Other Fine Cereals Pigments Gypsum Wood Air + Feed grinding Vegetables Paints Coating of PVC ground Soya Carbon black limestone Rubber product Fish meal Titanium dioxide Polyurethane Starch Plastics foam Fiber Iron oxide Bran Thickener Impact Proteins Cellulose de- PCC (precipi- Blood products drying Starch rivatives tated calcium PVC filter cakes Air Lactose Titanium dioxide carbonate) sus- Casein Pigment suspen- pensions sions Gypsum Press cakes Aluminium oxide TABLE 5: APPLICATIONS FOR CLASSIFIER MILLS Pharma/Food Chemicals Minerals Other Cacao press cakes Powder coating Limestone Proteins Sugar Paints Talc Wood FIGURE 6. Classifier mills achieve the Lactose Pigments Sodium bicarbonate highest fineness among mechanical Vegetable products Silica impact mills Gelatine Resins Alginate Wax PVC shaft. The feed material is charged pneumatically, for which a partial is also set by the rotor speed and the fiers. Because the grinding elements flow of the mill air has to be branched throughput of the feed material. and an air classifier are integrated off. Comminuted material follows the The rotor of the long gap mill consists into a single machine housing, this flow of air around the guide cone to of grinding stages located one on top type of mill is known as a classifier the classifying wheel. The high-speed of the other and separated from each mill. With classifier mills it is the in- classifying wheel allows only fines to other by discs. Each grinding stage tegrated classifier that controls the pass through it; coarse material is re- is equipped with a number of impact product fineness and not the speed jected and returned to the grinding plates. Exchanging the many impact of the grinding rotor. Classifier mills disc where it is reground. The cover plates is time-consuming, which is thus offer the advantage of the high- for the machine can be hinged back why machines are now available that est finenesses among the mechanical so that internals are easily accessible are equipped with continuous impact impact mills and stable product prop- for cleaning. bars that can be exchanged easily. The erties even if the properties of the feed Dictated by their function, deflec- rotor is surrounded by the grinding material are changing. These reasons tor wheels cannot be set to any coarse track, which is composed of grooved are the motivator behind the increas- value desired, but are limited to a top grinding track segments. An air clas- ing use of classifier mills. However, value of around 200 μm (assuming a sifier can be installed above the grind- these advantages give rise to higher feed material with a bulk density of ing zone. The classifier, however, does costs because a more powerful fan is 2,000 kg/m3). At high speeds, classi- not make a real classifier mill out of needed than with the simple rotor-im- fier mills compete with jet mills, and the long gap mill, because the recircu- pact mills. The fan sucks the transport at coarser fineness values, also with lation of the coarse material upstream air through the mill against the re- pin mills. Compared with jet mills, of the grinding zone is complicated. sistance of the classifying wheel. The the energy consumption of the clas- The long gap mill is especially suit- pressure drop at the classifying wheel sifier mill is comparatively low, and able for simultaneous grinding and can be several thousand Pascals. The compared with pin mills, it has advan- drying. (Further applications are given feed rate is usually controlled with the tages in terms of operating stability, in Table 4.) This is due to the fact that current of the mill motor. an exact top cut and a higher resis- there are no dead zones in which the A schematic of the most-widespread tance to wear. Over the course of the moist product could cake and deposit. classifier mill is shown in Figure 6. years, a number of different classifier Long gap mills are operated at periph- The maximum peripheral speed of mills have been developed, each of eral speeds of up to 150 m/s, and can these mills is up to 150 m/s; the air which have their strengths for certain grind finer than the simple impact classifiers run at peripheral speeds of applications (Table 5). mill as a result of the higher num- up to 60 m/s. This mill type has been Jet mills. In combination with an air ber of stressing events. They can also on the market since about 1970 and classifier, jet mills deliver the highest produce steeper particle size distribu- is built in over 20 machine sizes. The finenesses as a result of the high im- tions as a result of a narrow residence largest mills have a drive power of up pact speed and multiple stressing of time distribution. The largest mills of to 500 kW. the feed material. this type have rotor diameters of over The grinding disc is driven from Jet mills use the effect that com- 2 m and a drive power of over 1,000 below via a hollow shaft. The shaft for pressed gas is accelerated to extremely kW. Large long gap mills are by far the the conical deflector classifying wheel, high speeds when it is expanded in a largest fine impact mills. which has its own frequency-con- nozzle. Thereby, the energy contained Fine impact mills with air classi- trolled drive, runs through the hollow in the compressed gas in the form of CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009 29
- 36. TABLE 6: APPLICATIONSFOR THE FLUIDIZED-BED OPPOSED JET MILL Cool Delamination / Hard mate- Contamination-free Other Cover Story grinding deglomeration rial processing Toner Mica Abrasives Dental ceramics Silica Powder Talc Technical Fluorescent powders Flame retardants coating Ceramic Ceramics Silica gel Rare-earth-magnet heat is converted to kinetic en- Wax pigments Perlite Pharma auxiliaries materials ergy. The gas can even be accel- Plant Pigments Glass frits Acive pharmaceutical PTFE protectors Tungsten ingredients (API) Graphite erated to supersonic speed in a Paints carbide Laval nozzle. A Laval nozzle is characterized by its hourglass shape, which widens down- Feed Feed stream of the narrowest diame- Transport air ter in a similar way to Venturis. Air + Compressed air at 20°C and ground product between 6 and 8 bar overpres- sure is frequently used, in which case the exit velocity of Air + ground the air is approximately 500 product m/s. If the product permits, the Grinding compressed air is not cooled air downstream of the compres- sor, and jet mills are operated at elevated temperatures. Air Grinding air velocities of approximately 600 m/s can be achieved in this way. After exiting the nozzle, the FIGURE 7. The spiral jet mill is relatively simple speed of the jet drops rapidly as a result of air and product being terial at the periphery. This transports sucked in from the surroundings. the feed material into the jets of grind- FIGURE 8. This fluidized-bed opposed- jet mill has an integrated deflector-wheel If superheated steam is used as the ing air, where it is comminuted mainly classifier propellant, it is possible to achieve as the result of impacts between the speeds of over 1,000 m/s. A significant particles traveling at different speeds. to wear, and no fineness adjustment. disadvantage of grinding with steam, The air stream in the grinding cham- Spiral jet mills are employed in the however, is the tricky operation of a ber effects a spiral classification: fine chemicals industry for the dispersion system where the risk of condensation material is conveyed to the central of pigments. During a dispersion pro- in the downstream filter is high. This discharge opening, whereas coarse cess, the final particle size is dictated is the reason why more and more jet material is centrifuged back out to the more by the primary particle size in mill owners have meanwhile switched periphery. A high pressure builds up the feed material than by the air clas- from steam operation to compressed in the mill as a result of the air rotat- sification. Large mills have a diameter air mode. ing at high speed. This makes it neces- of the grinding chamber of approxi- Increasing demands on the prod- sary to use an injector operated with mately 1 m and consume up to 3,000 uct quality and the development of compressed air to feed the material; m3/h of compressed air. Small mills for the fluidized-bed opposed jet mill (de- with approximately 30%, the injector product development have diameters scribed below) have helped jet mill- requires a considerable share of the of only 30 mm. ing gain acceptance, even though the total air flow. Fluidized-bed jet mills. The fluid- energy consumption of jet mills is ex- The spiral jet mill has no fineness ized-bed opposed-jet mill came onto tremely high. Besides taking a look at control. At a constant air flowrate, the the market around 1980. The big ad- the fluidized-bed opposed jet mill, the feedrate is the main parameter used to vantage of this jet mill, when com- spiral jet mill, which continues to be adjust the fineness. A high throughput pared with the spiral jet mill, is the popular in the pharmaceuticals indus- results in coarse product because the integrated deflector-wheel classifier, try is also considered. spiral is decelerated, and this leads to which, together with the constant air Spiral jet mill. The spiral jet mill is a coarser classification. flowrate, ensures an extremely con- a simple piece of equipment. At the pe- The advantages of the spiral jet stant product quality. riphery of the flat-cylindrical grinding- mill — simple design, simple clean- The nozzles expand the compressed classifying chamber, compressed air is ing [(clean-in-place (CIP) capable] grinding air horizontally in the grind- expanded in nozzles that are pitched and simple sterilization [sterilize-in- ing chamber (Figure 8). In the case of at an angle of between 30 and 50 deg. place (SIP) capable] — have all com- frequent product change — that is, to the radius (Figure 7). This causes bined to ensure that this machine the desire to completely empty the a rotating air stream in the grinding has remained the standard machine vessel — additional bin floor nozzles chamber. The feed material, charged in the pharmaceutical industry for can also be used. The nozzle diameters to the grinding chamber through an fine grinding. And this is in spite of range from 1 mm with the small mills injector, becomes caught up in the ro- the disadvantages: high noise level in to 30 mm with the largest ones. The tating flow of air, is centrifuged and operation (injector), additional gas re- rising flow of air transports ground ultimately forms a rotating ring of ma- quirement for the injector, sensitivity product to the integrated classifying 30 CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009
- 37. EXAMPLES FOR ENDPRODUCTFINENESS igure 9 uses the example of grinding sugar in a pin mill to with a corresponding value-added factor allowing such a high F show that a parallel shift of the particle size distribution is achieved by changing the speed of the pin disc and by chang- ing the feedrate. The highest fineness of 99% < 90 μm is achieved effort for the size reduction. (Marble is not among these products, it is just used as an example here.) 100 at the highest speed and the lowest feedrate. In the example shown in Figure 10, the same feed material was 90 used for all machines, namely marble with a particle size of be- 80 6 5 4 3 2 1 tween 0.1 and 2 mm. In each case, the finest particle size distribu- 70 Undersize % tion produced in the tests with the specified mill type is shown. In 60 the coarser range, one can see that the particle size distribution merely makes a parallel shift. In the fine range, it is not possible to 50 achieve more than 10% under 1 μm; this is due to the integrated 40 classification and the high internal circulation factors. 30 The energy consumption increases strongly with increasing fine- 20 ness, which means that for a given system the capacity drops with 10 increasing fineness. Figure 11 shows the energy consumption ver- sus the median particle size for the same feed material as in Figure 0 1 10 100 1,000 10,000 10. The power consumption of the mill only is considered, without classifier, fan and other auxiliary units. With the jet mill, the jet particle size, m power was used for the calculation, and not the drive power of the FIGURE 10. The particle size distributions for marble compressor. In the range of median finenesses between 10 and achieved in different mill types. (1) feed material; (2) impact 100 μm, the specific grinding energy is around 10 kWh/m.t. (m.t. mill with crushing disk (Figure 3a); (3) impact mill with plate = metric ton). For the highest fineness, the energy consumption beater (Figure 3b); (4) double rotor pin mill; (5) classifier mill; goes up to around 1,000 kWh/m.t. There are only few products (6) fluidized-bed jet mill 1 Specific energy consumption, kWh/m.t. 10,000 0.9 Fluidized bed jet mill Double rotor pin mill 0.8 1,000 1 2 3 4 5 6 Pins 0.7 Plate beater % 0.6 100 Crushing disk Undersize Classifier mill 0.5 99% < m; kWh/m.t. 1 90 14.1 0.4 2 125 12.7 10 0.3 3 150 12.1 4 220 8.3 0.2 5 315 6.5 1 6 450 5.2 0.1 0 0.1 10 100 1,000 1 10 100 1,000 particle size, m Fineness x 50, m FIGURE 9. The particle size distributions for sugar FIGURE 11. Specific energy consumption for grinding grinding with a pin mill marble in different mill types wheel. Fines are able to pass through conventional jet mills is that commi- that at the same peripheral speed, the the classifying wheel, whereas coarse nution takes place exclusively in the cut point of classifying wheels shifts material is rejected and falls back into fluidized bed as a result of the par- into the coarse range with increasing the grinding zone. To ensure that a ticles impacting against each other, classifying wheel diameter. constant material level is maintained, and is thus largely free from wear, The fluidized-bed opposed-jet mill the metering unit is controlled by the because the particles never impact at has the following strengths: fine- power consumption of the classifier high speed against the machine wall. nesses down to 3 μm, depending on drive or the weight of the filled mill. The only wear-prone component in the the product density; low degree of Grinding takes place both in the mill is the classifying wheel, which wear, regardless of the product hard- individual jets themselves and in the can be protected by selection of a suit- ness; low product contamination; cool focal point of the jets. The gas jets in- able construction material. Monobloc grinding; easy cleaning; quiet opera- troduced into the particle bed fluid- classifying wheels made of aluminum tion; and SIP capabilities. These ad- ize the product and draw individual oxide and silicon carbide have proven vantages have served to open up a particles into the jets. Fine and light themselves in operation for even the wide range of applications for this mill particles are accelerated and blasted hardest and most abrasive products. (Table 6). The largest mills require up away at the circumference of the jet To prevent high pressure drops and to 15,000 m3/h of compressed air, and and cannot enter into the center with increased wear, it is necessary to op- the compressors needed to operate the the highest velocity. This problem erate the classifying wheels at the mill are equipped with up to 1,000 kW can be reduced with special multiple lowest possible peripheral speeds. For drive power. nozzles, which, in some cases, leads to large jet mills with high air flowrates, energy savings of 30%. the highest fineness values can best Pros and cons of different mills The major difference between the be achieved with several small clas- Certain product properties can lead fluidized-bed opposed-jet mill and sifying wheels. This is due to the fact to a mill being particularly suitable CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009 31
- 38. Cover Story TABLE 7: SUITABILITY OF DIFFERENT MILL DESIGNS FOR SPECIFIC APPLICATIONS Mill design Material properties Fine Long gap Dual-rotor Classifier Spiral Fluidized- impact mill mill pin mill mill jet mill bed jet mill Fineness > 100 μm > 80 μm > 32 μm > 10 μm > 5 μm > 3 μm Top cut - o - + + + Mohs' hardness < 3 + + + + + + Mohs' hardness > 3 o o - o - + Heat-sensitive materials o o - o + + Moist materials o + (1) o o - o Sticky materials o o + (2) - - - Machine sizes Rotor diameter, mm 50 – 1,800 200 – 2,800 50 – 1,120 50 – 2,000 30 – 1,000 (3) 40 – 1,800 (3) Drive power, kW 0.5 – 355 4 – 1,400 2x0.5 – 2x250 0.5 – 500 1,200 (4) + ideal; o suitable to a limited degree; - not recommended Footnotes: (1) The long gap mill is capable of processing products with a high moisture content — even liquid suspen- sions — provided that the air is preheated adequately; (2) In combination with wide-chamber design; ( ) Diameter of g ; (3) grinding chamber; (4) Drive power of compressor 1 6 4 FIGURE 13. 2 7 Flowchart of a pressure-re- 3 lieved process- ing system with classifier mill. [(A) feed; (B) 5 ground material; (1) metal sepa- rator; (2) feed metering screw; (3) classifier mill; (4) reverse FIGURE 12. A standard impact mill jet filter; (5) fan; system is composed of: a feeder (1), (6) explosion- magnetic separator (2), a mill plus barrier valve safety switch (3), a silencer (4), a (7) explosion product collection bin (5), an auto- venting; (8) fire matic filter (6) and a fan (7) extinguishing system; (9) rup- for a specific application or to it not ture disk] being suitable at all. Table 7 gives an overview of the suitability of various machine types on the basis of differ- be opened if the rotor is still running. an increasingly insignificant role. ent criteria. A suction-side silencer (4) reduces the Today, solutions are developed for the noise at the site of machine installa- individual market segments that are System engineering tion. A large part of the ground prod- more and more specific, whereby the An impact mill on its own is not func- uct accumulates directly in the fines peripheral conditions specified by a tional; it needs a more-or-less elabo- collection bin (5), whereas fine dust is product itself must always be taken rate system for operation. A standard collected in the automatic filter (6). A into account. system for the classic impact mill is suction fan (7) compensates the filter shown in Figure 12. Feed metering resistance in order to maintain a slight Explosion protection channels or screws (1) ensure a uni- under-pressure in the system and thus Even though dust explosions are form feedrate. A magnet in the feed prevent formation of dust. The rotary relatively rare, they can cause seri- chute (2) protects the grinding ele- valve at the base of the fines collection ous damage to people and machines ments from metallic tramp material. bin discharges the product and serves when they do occur. Besides preven- The door interlock (3) ensures that as an air-lock. tive measures, such as the avoidance the mill cannot be switched on if the In times with the focus on custom- of potentially explosive dust concen- door is open and that the door cannot ized solutions, standard systems play trations, the avoidance of critical oxy- 32 CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009
- 39. FIGURE 16. Thisfine impact mill inside FIGURE 14. Shown here is a an isolator features a mill housing and compact grinding system with grinding elements in monobloc design, pin mill and two air-locks and polished surfaces (Ra = 0.8 μm) FIGURE 15. Cryogenic grinding system operated with liquid nitrogen gen concentrations by inerting and [(A) feed; (B) ground material; (1) feed that the production personnel must the avoidance of ignition sources, there metering channel; (2) screw cooler be afforded effective protection. This are a number of design measures that supplied with liquid nitrogen (LN2); (3) has led to the increasing use of isola- dual-rotor pin mill; (4) automatic filter; can limit the damage in the event of (5) temperature sensor] tors (Figure 16). A machine is much a dust explosion. In laboratories, for more difficult to operate if housed in example, inerting is often used — like- perature can be cooled to make them an isolator, than under normal condi- wise in the pharmaceuticals industry. brittle enough to be subsequently tions. Grinding systems in isolators In the case of large systems, an explo- ground by impact. Cryogenic grinding are unique systems with every detail sion-pressure, shock-proof design is is used for spices to make sure that designed to users’ needs. too expensive, and pressure venting the flavor and aroma is preserved. At and a reduced explosion pressure is the same time, cryogenic grinding also Final remarks therefore used (Figure 13). Confor- increases the throughput. Other appli- During the last decades impact grind- mance with the explosion protection cations are the fine grinding of plas- ing has gone through several devel- directives 94/9/EC for manufacturers tics and rubber. The supply of nitrogen opments. Dust emissions of systems and 99/92/EC for owners became man- is controlled as a function of the mill have been reduced. Products have datory in the EU member countries in outlet temperature. The temperatures become finer and finer. Processes recent years. downstream of the mill often range have become more stable by using between 0 and –20°C. The nitrogen re- classifiers. Machines have become Compact system quirement is considerable and usually more reliable in continuous opera- In the case of brittle products that ranges between 1 and 3 kg of liquid N2 tion. Nowadays customized solutions have a low grinding energy, there is a per kilogram of product, which natu- are available for many applications. high mass flowrate of product through rally raises the costs significantly. Future developments will be: machine the grinding system. Thus, the system Figure 15 shows a cryogenic grind- diagnosis for planned preventative can be cooled by the product and does ing system operated with liquid ni- maintenance, noise reduction, energy not need additional cooling by an air trogen. Large sections of the system efficient grinding processes and use of flow through the system. A compact are insulated to reduce the nitrogen wear-resistant construction materials system without dust collector can be requirement, and the cold air is circu- to process harder products by impact designed for these applications. This lated. Operating in the “through-air” grinding. ■ is especially advantageous for poten- mode is out of the question because Edited by Gerald Ondrey tially dust-explosive products, because freezing water from the air would the system is so compact that it can cause the mill to ice up. Author Bodo Furchner is general easily be built in a 10 barg design to manager of the technical di- withstand dust explosions (Figure 14). Pharma systems vision of Hosokawa Alpine AG (Peter-Dörfler-Str. 13-25, This ensures a safe operation of the The demands posed by the pharmaceu- D-86100 Augsburg, Germany; Phone: +49-821-5906-0; Fax: system and saves investment costs. tical industry are very different, de- +49-821-5906-234; Email: An example for the use of such com- pending on whether active substances b.furchner@alpine.hosokawa. com), a position he has held pact systems is milling sugar, which is or additives are to be processed and since 1993. Prior to this, he preferably ground with pin discs (see in what form the medicine will be ad- was manager of Hosokawa Alpine's Test Center Mechan- also Figure 9). ministered. In the case of highly active ical Processing from 1995–1999, and worked substances, the batches are relatively in the company’s R&D department since 1987. Furchner earned a process-engineering degree Cryogenic grinding small, and thus so are the machines from the Technical University of Munich, as well as a Ph.D., which he earned while working as Some materials that are subject to and systems used to process these scientist at the Institute for Process Engineering plastic deformation at ambient tem- products. Another important point is in the team of Professor Mersmann. CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009 33
- 40. Cannon Instruments ofState College PA Feature Report VISCOSITY: The Basics An important concept, sometimes forgotten, FIGURE 1. (top left) is that viscosity is not a single-point measurement Flow cups are used for measuring the viscosity of inks Robert G. McGregor Brookfield Engineering Laboratories FIGURE 2. (top right) Capillary viscom- ost engineers know what vis- an values obtained at 0.1 or 0.01 rpm can M eters measure cosity is, but may have trou- be several orders of magnitude higherer kinematic viscosity ble explaining it. To be brief, than the one recorded at 20 rpm. viscosity is resistance to flow. Raw materials in the chemical pro- o- FIGURE 3. (left) For handlers of all materials that flow, cess industries (CPI) usually have a Rotational viscom- either while being processed or in an reported viscosity value on the data ta eters (this one with end-use, it is important to think about sheet that accompanies the product. t. a disc spindle) the materials’ flow characteristics. Data sheets for some polymer solu- measure dynamic viscosity The bottom line is to come up with tions, for example, may include a ways to measure viscosity so that you discrete number like 4,500 centi- can quantify whether a material will poise (cP), but no further informa- measure how much time it would take flow the way it needs to. tion about how the measurement was to drain the ink (Figure 1). The cups This article reacquaints the reader made, not even the test temperature were relatively inexpensive and any- with the basic concepts and terminol- at which the polymer was measured. one working the press could easily ogy for viscosity and addresses tech- To perform a valid verification check learn how to make the measurement. niques to quantify it. An important and confirm that the material is This became one of the earliest qual- concept, sometimes forgotten, is that within specification requires a dupli- ity control (QC) tests that checked a material’s viscosity is not a single- cation of the test method used by the systematically for viscosity in a quan- point measurement, but often depends manufacturer. The only alternative in tifiable way. But the cup method could on a number of factors. these situations is to find the proper not always discriminate successfully Take asphalt, for example. The authority at the manufacturer and ob- between inks that proved acceptable standard test method for pumpability, tain the relevant test details. and those that were marginal or out- according to ASTM D4402, is to use The printing ink industry is one right poor performers. a regular viscosity (RV) torque rota- of the best examples to illustrate The problem turned out to be a tional viscometer at 20 rpm or a low the need for viscosity measurement. matter of understanding “shear rate” viscosity (LV) instrument at 12 rpm. When the ink is too thick, smearing and how it can affect the viscosity of Record the viscosity value, make sure may result during printing; too thin the ink. When testing inks, or any that it falls within prescribed maxi- and there can be serious fading of material that flows, it is important mum and minimum limits, and then the printed image. There was a time to think about how the material will report whether the number passes or when pressmen could tell by rubbing be processed or handled when in use. fails. However, this straightforward an ink between their fingers as to how The “shearing action” that the mate- single-point test does not provide the well it would perform “on press”. This rial will undergo is the analysis that complete picture for asphalt flow be- rubbing action was, in essence, a vis- we want to focus on. For inks, the use havior. When pumping asphalt, the cosity test, the objective being to tell of a rotational viscometer running at startup torque required to get the how much resistance was felt between different speeds can simulate, in part, pump going initially suggests that a thumb and forefinger. what is happening to the ink during second viscosity test at a much lower Printers developed a more scientific transfer to a substrate. This analytical rotational speed makes sense. Experi- approach to viscosity measurement by procedure for simulating the shearing ments have shown that the viscosity using cups with holes in the bottom to action with an instrument is the key 34 CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009
- 41. TABLE 1. COMMONMATERIAL VISCOSITIES Material Viscosity (cP) Benzene 0.6–0.7 Sulfuric acid 20–30 Motor Oil SAE 30 150–300 Glycerin 1,000–2,000 Glycerol 1,400–1,600 Asphalt emulsion >5,000 Grease >100,000 FIGURE 4. Spindle geometries include: a) Disc; b) Cylinder; c) Cone; d) T-bar; e) Vane to predicting flow behavior and leads the same, no matter what shearing ac- There is a way to correlate viscos- to the selection of an appropriate vis- tion takes place), so the high precision ity measurements made with dynamic cometer to perform the test work that of these instruments is very important and kinematic methods for materials is required. to achieving accurate viscosity values. that are Newtonian using the follow- ing equation: Kinematic viscosity Dynamic viscosity Dynamic Kinematic Returning to the cup method, note that Rotational viscometers (Figure 3) = Density (2) viscosity viscosity this type of test uses the force of grav- have become a widely accepted tool for ity to drain the ink out of the cup. The the measurement of viscosity across For non-Newtonian fluids, however, shearing action on the ink takes place a number of industries, including the dynamic viscosity must be deter- at the orifice on the bottom of the cup. certain parts of the petroleum refin- mined for each shear rate according to As the ink level in the cup goes down, ing world, especially those concerned Equation (1). the shear rate at the orifice decreases with low temperature behavior. The Shear stress: The type of spindle because the weight of the ink remain- spindle, when inserted into the test used to shear the material is an im- ing in the cup is less and less. This liquid, rotates at various fixed speeds, portant consideration for making vis- type of measurement, where gravity thereby shearing the material contin- cosity measurements. The standard is the driving force, is referred to as uously at defined shear rates. Simul- disc-type spindle is most commonly kinematic viscosity. taneously the viscometer measures used throughout the world since its The petroleum refining industry is the amount of torque resistance expe- introduction 75 years ago. Since then, a major user of capillary viscometers rienced by the spindle at each speed a variety of spindle geometries have (Figure 2), which like the flow cups, of rotation. This torque measurement come into existence including cylin- also measure kinematic viscosity. A is quantified as a “shear stress”, which drical, cone, T-bar, vane and many measured sample volume of the fluid acts across the surface area of the im- others of various shapes (Figure 4). flows under the influence of grav- mersed portion of the spindle. These The most used geometries for “defined ity between two etched lines on the two key concepts — torque resistance shear rate” calculations are coaxial tube, and the time of flow is recorded. and shearing action — have been com- cylinder (cylindrical spindle in a cy- Taking into account the calibration bined into an equation that defines lindrical chamber) and cone/plate; the constant of the capillary tube, these dynamic viscosity as the ratio of shear equations that define shear stress and highly precise instruments report stress to shear rate: shear rate for these configurations are data in scientific units of mm2/s, or shown in Figures 5 and 6. centistokes (1 cSt = 1 mm2/s). The The benchmark material for com- standard test method for many liquid (1) paring the viscosity of all materials is petroleum-derived products is ASTM water. The National Institute of Stan- D445, which also requires strict tem- The unit of measurement used to dards and Technology (NIST; Gaith- perature control when measuring vis- quantify rotational viscosity is the ersburg, Md.) states that the viscosity cosity with the capillary viscometer. centipoise (cP) in N. America and most of water is 1 cP when measured with a This recognizes the effect of tempera- of S. America, and the milliPascal- capillary viscometer at a temperature ture on flow behavior and the need to second (mPa-s) in other countries, al- of 20°C. Table 1 shows the viscosity of standardize test results by holding though there is some degree of overlap select materials, to give an idea of how temperature constant. Petroleum-de- in useage. The fortunate news is that they compare to each other. rived materials tend to be Newtonian the two units are interchangeable be- Shear rate: Shear rate is a reflection by nature (the viscosity value remains cause 1 cP = 1 mPa-s. of the process characteristics as op- CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009 35
- 42. Feature Report M T Shear stress, dynes/cm2 = Shear stress, dynes/cm2 = 2 2 Rb2L / 3 r3 2 Rc2Rb2 Shear rate, s –1 = Shear rate, s –1 = Sin Rb2 (Rc2 - Rb2) Shear stress Viscosity, cP Shear stress X 100 Cone Plate Viscosity = or mPa-s = Shear rate Shear rate M = Torque acting on surface of spindle L (instrument reading) = Angular velocity of spindle, radians/s = 2 /60 x N where N = spindle rpm T= Torque, dyne-cm Rc = Radius of container (outer boundary) r= Cone radius, cm r Rb = Radius of spindle (bob) = Cone speed, radians/s Rb = Cone angle, degrees L = Effective spindle side length Rc FIGURE 5. Coaxial cylinder geometry calculations FIGURE 6. Cone-and-plate geometry calculations Shear rate calculation for pipe flow Shear rate (flow gradient) Volume flowrate Q = A V AVG V = Velocity, cm/s Velocity difference between plates Moving plate = Distance separating plates X V, cm/s = X, cm Stationary plate V, s-1 = Where A = Pipe cross-sectional area X V AVG = Average velocity of fluid in pipe Assumption: Plate length is significantly greater than distance between plates 6Q = d3 FIGURE 7. This shows graphically how shear rate is quantified FIGURE 8. Shear rate can be calculated for pipe flow posed to the process liquid properties tion in a mixer. The blades are equiva- is not a single number for them. themselves and must be quantified lent to the moving plate and the side Pseudoplasticity: The most common separately. Imagine that the fluid you wall is the stationary plate. The angu- type of viscosity behavior is pseudo- want to test is sandwiched between lar velocity of the blades is easily com- plasticity, where a material’s viscosity two plates separated by a known dis- puted based on the rotational speed of decreases as the shear rate increases. tance. Keep the bottom plate station- the mixer; the distance from the blade This behavior can be characterized ary and move the top plate at a de- to the side wall is a known dimension by a flow curve or rheogram (Figure fined velocity. Shear rate is the ratio provided by the manufacturer. The 9). Many of the materials mentioned of the moving plate velocity, V, to the equivalent shear rate is simply the in this article, with the exception of distance separating the plates, X. ratio of those two numbers. water and select petroleum refining A similar calculation can be done for products, are pseudoplastic. Water is Shear rate = V/X (3) the shear rate of fluid flow in a pipe, always 1 cP at 20°C no matter what The unit of measurement for shear as shown in Figure 8, assuming that shear rate is used. Just as materials rate is reciprocal second or s–1. This the velocity profile of the fluid changes that do not change in viscosity with approach to quantifying shear rate as- linearly from the pipe wall to the cen- shear rate are referred to as Newto- sumes that the fluid behaves in a uni- ter of the pipe where maximum veloc- nian (in honor of Isaac Newton who form way as shown by the arrows in ity occurs. Although a linear change in first postulated the parametric rela- Figure 7. The layers of fluid molecules velocity profile is not the usual case, tionships discussed earlier in this ar- slide over each other in a repetitive it provides a convenient starting point ticle), those which do change are called fashion such that the closer you get to for an initial calculation. non-Newtonian. the moving plate, the faster the layer Thixotropy: A related issue that af- is moving. Material behavior fects measured viscosity values is the Table 2 gives several examples of With these fundamental concepts length of time for the shearing action. shearing action and the shear rate as- in place, the important conclusion If a material is sheared at a constant sociated with each. The thing to rec- to recognize is that many CPI ma- rate and the viscosity decreases over ognize is that you can easily compute terials are non-Newtonian and will time, we call that thixotropy. Some the relevant shear rates for your own change in viscosity as the shear rate materials exhibit thixotropic behavior, situation. Consider the shearing ac- is adjusted, in other words, viscosity but recover completely once the shear- 36 CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009
- 43. TABLE 2. TYPICALSHEAR RATES Situation Typical shear rate range (s–1) Application Sedimentation of fine powders in asuspending 10–6 to 10–4 Medicines, paints liquid Leveling due to surface tension 10–2 to 10–1 Paints, printing inks Draining under gravity 10–1 to 101 Painting and coating, toilet bleaches Extruders 100 to 102 Polymers Dip coating 101 to 102 Paints, confectionery Mixing and stirring 101 to 103 Manufacturing liquids Pipe flow 100 to 103 Pumping, blood flow Spraying and brushing 103 to 104 Spray drying, painting, fuel atomization Milling pigments in fluid bases 103 to 105 Paints, printing inks High-speed coating 105 to 106 Paper Lubrication 103 to 107 Gasoline engines shear stress, dynes/cm2 shear stress, dynes/cm2 viscosity viscosity shear rate, s-1 shear rate, s-1 shear rate, s-1 shear rate, s-1 FIGURE 9. Flow curves, or “rheograms” are used to charac- , FIGURE 10. This flow curve shows thixotropy in a pseudo- terize pseudoplastic behavior plastic material ing action stops. This is important tures as shown for the ink sample in Thix Index. Viscosity measurements because the material will not behave Figure 11. This allows manufacturers are made at two separate speeds, nor- as expected by the end user if the loss and users alike to take into account mally an order of magnitude apart, in viscosity is permanent. For pseudo- variable ambient conditions that may such as 50 rpm and 5 rpm. The viscosity plastic materials, the way to observe exist in plants around the world, espe- value at 5 rpm is divided by the viscos- whether thixotropy occurs is to run cially if the viscosity measurement is ity value at 50 rpm. For a pseudoplastic an up/down test (increase the spin- made out on the plant floor and not in material, the ratio of the two viscosities dle speed, then decrease the spindle a controlled lab environment. is a number that is greater than 1. The speed) and see if the data for the flow higher the Thix Index value, the more curves are separate, as shown in Fig- Measuring viscosity shear thinning the material will be. ure 10. The spatial area between the Quality control personnel have a bet- Some resins companies use this tech- curves is an indicator of how signifi- ter opportunity to perform effective nique regularly and report values as cant the thixotropic behavior may be. testing when the above concepts are high as 4, which indicates significant If the curves lie on top of each other or applied to materials handled or pro- pseudoplastic behavior. are relatively close together, there is duced in the plant. Most companies Formulations are constantly chang- little to no thixotropy. use a single-point test to check for vis- ing as new additives are introduced Temperature: Temperature is an- cosity, which means a defined spindle to enhance the product behavior or other key parameter that must be con- running at a single speed. Hopefully, appeal. Textured particles in paints, sidered when measuring viscosity. As more thorough testing has already modified asphalts with various filler temperature increases, most materials been performed showing complete materials and specialty polymers are exhibit a decrease in viscosity. So it is flow curve behavior so that the choice only a few examples that show the important to define the temperature of a single point is relevant and can need for thorough viscosity testing. at which the viscosity measurement is distinguish good material from that of They clearly suggest that a single- made to ensure consistency of results. lesser quality. point test is not enough to give the full When new materials are evaluated, it Thix Index: Some CPI companies picture in QC and that a more detailed is common to perform a temperature recognize the need for more than one analysis will be required. The Thix profile test. Run a series of up/down viscosity measurement in QC and use Index can bridge the gap temporarily, shear ramps at discrete tempera- a long-established method know as the but the ultimate realization is that a CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009 37
- 44. Feature Report 300 100 Epoxy cure Temperature 90 (gelation 275 65° F 80 algorithm) 250 70° F 70 75° F Viscosity, cP 225 60 80° F Torque, % 200 85° F 50 90° F 40 175 30 150 20 125 10 100 0 0 50 100 150 200 250 300 350 0 200 400 600 800 1,000 Shear rate, 1/s Time interval, minutes FIGURE 11. A viscosity-temperature profile for an ink FIGURE 12. These torque data are for a cure test on an epoxy sample is shown with data from shear ramp tests A four bladed vvane is inserted into the sample. The motor drives sample at a controlled rate. The torque increases until the vane exerts enough force o the material to on cause the spindle to start rotating spind At low speeds the vane geometry behaves like a concentric cylinder system FIGURE 14. Vane spindle geometry may be preferred for yield stress measurements of FIGURE 13. Controlled stress rheometers higher viscosity materials can accurately measure yield stress true viscosity flow curve is needed, and turers who need to know how a reac- The advantage of today’s instruments this should become part of the data file tion is progressing as evidenced by the with built-in microprocessors is that that goes with the product record. buildup of viscosity in the material. the test runs can be unattended, and Today’s instrumentation is fully ca- The viscometer measures viscosity the data are captured automatically pable of running multiple point tests continuously as it builds over time, by a personal computer. and capturing the data without opera- while rotating the spindle at a de- Yield stress: Viscosity may be the tor involvement. This more-involved fined speed, say 100 rpm at the outset. primary variable of interest, but capability does not take any more When the torque reaches a defined there is a related parameter called labor to accomplish. In fact, it may re- maximum, say 95% for example, the yield stress that is critical to measure quire less since the results don’t have spindle speed automatically drops by for some materials. Yield stress is the to be manually written down, but in- an order of magnitude to 10 rpm, and amount of force that is required to get stead are captured automatically. the measurement continues without a material to begin flowing. Returning Curing algorithm: One new test interruption. Again, when the torque to the asphalt example earlier in this method that has become readily avail- reaches 95% as the material continues article, the idea can be applied to any able to the CPI through the inexpen- to build viscosity, the speed drops to 1 pumping situation. In order to move sive automation of instrumentation is rpm, and so forth. The standard instru- the material from one point to an- the “curing algorithm,” which allows ment shown in Figure 3 can go down other, the startup torque required for prediction of an endpoint in a bench- to 0.01 rpm. Figure 12 shows the type the pump must be calculated so that top test. This applies to adhesives, of viscosity data that results. In addi- the pump is sized correctly. Therefore, asphalts and select polymer manufac- tion, the time to cure is also recorded. the yield stress in the material must 38 CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009
- 45. Test Method Test Data Static Yield stress yield is reached Shear stress stress when the test spindle Static yield Stress begins to value rotate = Data point Time Shear rate FIGURE 15. Yield-stress-test data are obtained from a controlled stress rheometer be measured and used as the basis Generate for choosing a pump with suffi- flow curve cient startup torque. Shear stress Dynamic yield The controlled stress rheometer Use “best fit” stress value Y line for data is the tool of choice for measuring yield stress (Figure 13). The choice Extrapolation to zero = Data point of spindle geometry must again = Best fit shear rate be considered. If the quantity of determines available material is limited, say 2 yield stress Shear rate mL or less (which is often the case with specialty polymer formula- FIGURE 16. When a controlled stress tions), the cone/plate or plate/plate rheometer is not available, yield stress can system is the best choice. Alterna- be approximated using flow-curve data tively, coaxial cylinder geometry may also be considered if the avail- don’t fit into the budget when this able sample size is between 2 and 20 type of information is first needed. mL. When sample size is not an issue, An alternative approach is to use the then vane spindle geometry may be flow curve data (shear stress versus preferred. One advantage of vanes is shear rate) from a standard benchtop that the material trapped between the viscometer and extrapolate the data vanes is shearing against the mate- to zero shear rate conditions (Figure rial outside the circumference of the 16). This provides a value for what the spindle (Figure 14). Other spindle ge- yield stress might be, but is most likely ometries sometimes have the problem not as accurate as the controlled rhe- referred to as “slip”, where the mate- ometer method. If the test is repeated rial in contact with the spindle surface on multiple samples, and similar val- does not move at the same velocity as ues are achieved, the result can be the the rotating spindle. The vane spindle basis for at least a ballpark value for overcomes this potential problem. yield stress. The test method for controlled stress Edited by Dorothy Lozowski is to run a shear ramp. Increasing torque is applied to the spindle until References rotation begins, which is essentially 1. Brookfield Engineering Laboratories, “More Solutions to Sticky Problems”, available at the onset of yield stress. The method is www.brookfieldengineering.com. depicted in Figure 15. The test is usu- ally short in duration and provides a Author numerical value that can be used by Robert G. McGregor, is the process engineers for determining the sales and marketing manager for Brookfield Engineering yield stress of the material. This in Laboratories, Inc. (11 Com- turn can be used in sizing calculations merce Blvd., Middleboro, MA 02346; Phone: 508–946–6200 for the pump and the startup torque ext. 143; Email: r_mcgregor@ performance as well as steady opera- brookfieldengineering.com; Website: http://www.brook tion at full flow conditions. fieldengineering.com). He Controlled stress rheometers are holds M.S. and B.S. degrees in mechanical engineering from expensive instruments and sometimes MIT in Cambridge, Mass. Circle 18 on p. 54 or go to adlinks.che.com/23017-18 CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009 39
- 46. Engineering Practice FeatureReport REACH: Looking Beyond Be Pre-registration R E A C May 31 2 Registration deadline for phase-in substances: 1–100 m.t./yr May 31 Registration deadline for phase-in The next steps to ensuring compliance H 0 1 2 0 13 substances: 100–1,000 m.t./yr 8 are significantly more complex Nov. 30 Registration deadline for phase-in 2010 substances: Nancy Russotto >1,000 m.t./yr Entry into force >1 m.t./y CMRs Steptoe & Johnson LLP Jan. 1 >100 m.t./yr June 1 – aqu. tox. Dec. 1 2009 ailure to register under REACH F June 1 June 1 closes EU markets for thousands 8 200 Agency 200 list + SIEF of chemical substances manufac- 7 2008 start up tured or marketed in the Euro- pean Union, whether on their own, in Chemicals Pre-registration & preparations (formulations) or released agency Voluntary early prepare chemicals from articles (finished products). A key start up REACH registration safety assessments policy objective of registration under REACH (EC Regulation 1907/2006 FIGURE 1. The next major deadline in the REACH timeline is November 30, 2010, on Registration, Evaluation, Authori- at which point substances meeting the following criteria must be registered: 1) clas- sified as carcinogenic, mutagenic or toxic to reproduction (CMR) in quantities ≥ 1 zation and Restriction of Chemicals) m.t./yr; 2) classified as very toxic to aquatic organisms and that may cause longterm — to shift the burden of proving the adverse effects in the aquatic environment (represented as aqu. tox. above), in quan- safety of chemicals to the private sec- tities ≥ 100 m.t./yr; 3) phase-in substances manufactured or imported in quantities ≥ tor — is officially underway. 1,000 m.t./yr per manufacturer or per importer EU Member States are in the process of issuing national rules on sanctions raises awareness of some of the related (from fines and market withdrawal to initiatives that companies might need organisms and that may cause criminal penalties) for non-compliance or wish to consider. For an explanation longterm adverse effects in the with REACH. Equally, customers are of what falls under REACH, see the aquatic environment, in quantities demanding proof of REACH compli- box, p. 42. Meanwhile, for more about ≥ 100 m.t./yr ance. Companies that did not prereg- the specific requirements of REACH, ister (see box, p. 41) are legally bound see CE, March 2008, Cover Story Part imported in quantities ≥ 1,000 m.t./yr to suspend sales and manufacturing in 1, Are You Ready For REACH? and per manufacturer or per importer the EU and immediately prepare for Part 2, REACH: A Timely Overview. submission of a registration dossier. Supply chain communications With all attention to date focused Registration deadlines REACH requires supply chain com- on pre-registration, few companies Dates for registration depend on the munications, particularly for the pur- planned beyond that stage in the pro- type of substance, volume and hazard poses of registration, among substance cess. It is becoming increasingly ap- classification (Figure 1). Every com- manufacturers, formulators, article parent that the next steps to ensure pany must ensure that its REACH- producers, importers, distributors and compliance under REACH are signifi- relevant products are placed in the downstream users both within and cantly more complex and require not appropriate order of priority for ful- outside of the EU. only technical skills but also substan- filling the requirements. Note that REACH requires suppliers of ar- tial legal advice, supply chain man- the first registration deadline for ticles containing substances of very agement and adjustments in logistics. properly pre-registered substances is high concern (SVHCs) to forward Compliance can also engender finan- November 30, 2010, at which point information on these substances, if cial consequences that need to be care- substances meeting the following cri- contained above a concentration of fully managed. teria must be registered: 0.1 wt.%, to the industrial or profes- This article sets out the key steps sional user (or distributor) being sup- that every company must understand, or toxic to reproduction in quantities plied with the article. If a consumer suggests pitfalls to be avoided and ≥ 1 metric tons (m.t.) per year requests such information, REACH 40 CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009
- 47. ABOUT PRE-REGISTRATION re-registration, which closed on December 1, 2008, was the essential first step in P order for potential registrants of certain ”phase-in“ substances (mainly substances listed in the European Inventory of Existing Commercial Chemical Substances; EINECS) to benefit from extended registration deadlines. These deadlines varied ac- cording to the hazard classification of each chemical and volumes manufactured in, or participation in a consortium is volun- imported into, the EU. The 2.5 million pre-registrations completed prior to the deadline tary and is motivated by the mutual exceeded the anticipated number by 2.3 million and illustrated the effort by companies benefit of its members. The duration of worldwide to ensure continued market access in the EU. While it is estimated that this a consortium and its relevant SIEF are number is inflated by duplicate and superfluous pre-registrations, it is clear that between not necessarily the same. The duration 100,000 and 150,000 substances were legitimately pre-registered. of a consortium may extend beyond the Pre-registrants benefit from continued lawful market access for the pre-registered sub- stance until the relevant registration deadline. Companies that missed the December life of the SIEF, post June 2018, or vice deadline must fulfil their registration requirements now in order to continue to market versa. There may also be differences in legally in the EU. membership. Participants in the SIEF will include the following: 1) registering Late pre-registration manufacturers, importers or so-called Late pre-registration for new parties is available, only under limited conditions. It is Only Representatives; 2) parties whose possible for companies that fall under a narrow set of criteria to pre-register after the substances are regarded as being reg- deadline. The exception applies to the following: istered because they are regulated by the Plant Protection Product Directive or Biocidal Product Directive; and 3) data holders that are not required to released under normal or reasonably foreseeable conditions of use). preregister under the regulation but that wish to join the SIEF in order to requires that the supplier provide the early) to be safe. Such timing would sell relevant data (for example, labora- same information within 45 days of allow a technical completeness check tories, trade associations, and certain receipt of the request. and make sure that the registration is downstream users). In contrast, consor- In today’s markets where sensitivi- officially completed in time for other tia will not necessarily involve all SIEF ties to environmental and health im- members of the SIEF to refer to the members and may include participants pacts run high and campaigns target lead registration dossier. who are not part of the SIEF, like third products that allegedly expose con- The immediate priority during the parties that are not data holders (for sumers to unwanted risks, companies current pre-SIEF period (between the example trade associations or service must deal not only with formal regula- end of the pre-registration window on providers, such as law firms) or those tory requirements but must also pro- December 1, 2008 and the formation producing or importing a substance in tect their markets by adequate and of the SIEF) is for all the pre-regis- the EU for the first time after closure of appropriate communications through- trants for each substance to agree the pre-registration window. out the supply chain. on substance sameness. This means Many of these same management agreeing that the substances have considerations apply to consortia. Cooperating with competition the same chemical identity, in other Companies need to analyze the busi- Pre-SIEF and SIEF. For the first words, that the chemical composi- ness value of creating or joining a time under REACH, all competitors tion and hazard profile of a substance consortium. They should evaluate the having pre-registered a phase-in sub- produced from different sources are financial demands inherent in joining stance need to organize themselves sufficiently similar to be part of the such groups and, in some cases, partic- to provide or generate data required same joint registration. ipate actively in the determination of for registration. Because members of Because the pre-SIEF and SIEF the fees. Another critical step for each a SIEF (Substance Information Ex- activities bring together competitors, company is to ensure protection of its change Forum) need to agree on the members need to ensure that the own intellectual property as data shar- group’s “Lead Registrant”, companies management of meetings protects in- ing mechanisms are implemented. need to determine the profile they dividual companies from any poten- Legal agreements will need to be wish to adopt in each substance-re- tial infringement of competition (anti- drafted concerning, among other lated SIEF. For example, a company trust) rules. On a company-specific things, consortia, confidentiality, data whose substance is of great commer- level, professional guidance will be licensing, cost-sharing, lead-registrant cial value might wish to be involved required to handle areas such as data obligations and work with contract in the management of the SIEF, even evaluation and cost-sharing of exist- laboratories. to become its Lead Registrant. For ing data or data to be generated by Competition, or anti-trust, compli- substances of lesser business value, a the group. Many companies are opting ance is an area that companies need more passive role might be appropri- for entering, or have already entered, to examine both to ensure the proper ate. It will be important to assess the into consortium agreements with management of pre-SIEF, SIEF and time and financial investment relative their competitors in order to formalize consortia meetings and their docu- to the profile adopted. the terms on which they cooperate in mentation and to prepare individuals In either case, it is important to note order to fulfil REACH obligations. in the company for appropriate be- that the members of a given SIEF are Cooperation with competitors in a havior at such collective meetings and being urged to to submit lead registra- SIEF is mandatory for phase-in sub- in correspondence with competitors. tion dossiers by June 2010 (six months stance pre-registrants. In contrast, Training should be organized and, CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009 41
- 48. Engineering Practice where absent,competition compliance schemes developed and documented. WHAT FALLS UNDER REACH? Data management requires a se- ach EU manufacturer or importer of certain substances in volumes of 1 metric ton cure, user-friendly information tech- nology (IT) system for management of a company’s complete compliance ac- E (m.t.) or higher — whether alone, in preparations (formulations) or contained in finished products (articles) and intended to be released under normal or reasonably foreseeable conditions of use — must register that substance with the European Chemi- tivities. With varying deadlines, differ- cals Agency (ECHA). ent levels of participation in collective In addition, certain specific information must be provided to ECHA for each substance in an article that meets certain criteria and is defined as a “substance of very high con- groups, data provision or generation cern” (SVHC) in the “candidate list” of substances subject to authorization. activities, financial and logistical con- Eventually, legally marketing of candidate-list substances will only be allowed if the sub- siderations, a company will be quickly stances are formally authorized by ECHA. Such authorization will only be granted if it can overwhelmed if there is not a manage- be shown that the socio-economic benefits of the substance’s use outweigh its public health ment system in place for tracking in- and environmental risks and that there are no less-dangerous, suitable alternatives. volvement and managing deadlines. Finally, even substances in smaller quantities than the 1-m.t. threshold may be subject to obligations under REACH, including those obligations concerning restrictions, autho- Business strategies rization and Safety Data Sheets (SDS). Every company will need to develop REACH affects the following operators in the chemical substances supply chain: its own strategy for sourcing data to fill crucial data gaps, including the fol- OPERATORS AFFECTED BY REACH lowing: literature search and review; Established in the EU Established outside of the EU data valuation; study protocol recom- Manufacturers Manufacturers mendations; provision of cost esti- Importers Formulators (for instance, dye pro- mates; sourcing contract research or- ducers) ganizations and studies (for instance, Exporters out of the EU Exporters into the EU acquisition from other SIEF members, further testing and so on). Downstream users Producers of articles Each company will need to review Distributors the adequacy of registration activi- Producers of articles ties and determine further measures needed. The preparation of Chemi- cal Safety Assessments (CSAs) and respond effectively to questions raised importance that these relationships Chemical Safety Reports (CSRs) by the European Chemicals Agency or be well managed. Issues need to be needs to be organized or adapted to national authorities. anticipated, and creative solutions to the REACH requirements. Classifica- Authorization dossiers require spe- real and perceived difficulties should tion and labelling considerations need cial care in their submissions and will be provided. to be understood and the appropriate need to include relevant socio-eco- Edited by Rebekkah Marshall value chain communications imple- nomic and alternatives analyses. mented. In some instances, there may Product defense. REACH has al- Author be a need for product-specific advo- ready sparked significant pressures Nancy Russotto is a Eu- cacy with regulators at either the EU from suppliers and customers to de- ropean affairs advisor in the Brussels office of Step- or national level. fend substances against deselection toe & Johnson LLP (Av- A company with multi-national or by the market and restrictions to use. enue Louise 240, Box 5, B-1050 Brussels, Belguim; global activities needs to be aware of Constructive interaction with policy Phone: +32-2-626-0500; the increasing appeal of REACH to makers, not only in Europe but also Fax: +32-2-626-0510; Email: nrussotto@steptoe.com), regulators in other parts of the world, in the relevant world regions, will be where she is a member of from the U.S. State of California to the a necessary part of protecting mar- the Regulatory & Industry Affairs Department. Ms. Rus- People’s Republic of China, and the kets for substances and managing sotto offers business consulting and advisory services to various clients operating in the Eu- possibly of equivalent legislation being the development of and transition to ropean Union. Ms. Russotto’s extensive career in adopted outside the EU. REACH is alternative products. Companies need the European regulatory arena gives her unique insight that directs her consulting services, such seen by many as a desirable evolution to integrate such considerations into as developing strategies for effectively interfac- in chemicals legislation; and because it their REACH compliance strategies. ing with European regulators; adapting corpo- rate strategy and activities in the EU to the local is having a worldwide impact, it will be Value chain relationships. As culture; identifying sectors and/or companies an attractive package for regulators to mentioned under “supply chain com- with shared interests and establishing relation- ships that will maximize the impact of advocacy consider. Companies may wish to make munications” above, the relationships activities. Prior to joining Steptoe, Ms. Russotto led the Association of Plastics Manufacturers in their views known on such an evolution between each level in a substance’s Europe, which became pan-European under the in their own region with well-prepared so-called value chain will become name PlasticsEurope. As executive director, she gained in-depth experience in formulating and and documented information. increasingly important as debate in- representing the views of the plastics industry in Post-registration brings its own re- creases around the safety and role the European regulatory environment, and was at the forefront of creating and leading cross- quirements, for example, the need to of specific substances. It is of critical sector industry coalitions. 42 CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009
- 49. Operations & Maintenance Solids Processing Keeping Cooling Water Clean Source: Nalco Co. Proper monitoring OH – Na+ Ca+2 Cl– and control of O2 Fe+2 SO4–2 O2 water chemistry Fe(OH)3 Fe(OH)2 H+ Water OH– OH– Fe0 Fe+2 Fe0 is essential Fe 0 Fe0 e– e– Electrons e– e – e– e– Brad Buecker Anode Steel Cathode AEC PowerFlow C ooling water systems that FIGURE 1. In a basic oxygen corrosion cell, iron dissolution and metal loss occur rely on cooling towers are a at the anode, and oxygen reduction takes place at the cathode critical component at chemi- TABLE 1. REPRESENTATIVE cal process industries (CPI) are supplied from these sources. Table LAKE WATER ANALYSIS facilities. However, during operation, 1 provides a representative analysis Ion Concentration, mg/L these open recirculating systems of the water quality from a lake in concentrate the contaminants in the the Midwest that supplies a large Calcium 60 makeup water, and as a result, scale power station. Magnesium 12 formation and biological fouling can Although fresh water has relatively Sodium 32 occur. To manage this problem, all low levels of the minerals calcium and cooling water systems require proper magnesium, scale may form during Potassium 7 chemistry control and monitoring. summer months, even in once-through Chloride 32 Unless prevented, corrosion and the condensers and auxiliary heat ex- Sulfate 77 build up of scale and microbial fouling changers, because of the higher sea- Bicarbonate 163 can impact cooling efficiency and in sonal water temperatures. Given the extreme cases even lead to unit shut- huge number of heat exchangers and Nitrate 0.5 down. This article examines some of condensers at refineries, chemical Silica 2 the fundamental concepts and treat- plants, power plants and other chemi- Iron 0.1 ment options that should be consid- cal process facilities, any exchangers Manganese 0.1 ered to keep open, recirculating cool- that rely directly or indirectly on a ing systems clean. raw water supply for cooling may be When handling any water-treatment subject to fouling. minimize corrosion. Nonetheless, cor- chemicals (both oxidizing biocides and If the water used in an open recir- rosion protection is still important, so non-oxidizing treatment regimens), culating system has not been prop- we will examine some corrosion fun- safety is an absolutely critical issue. erly treated to remove unwanted damentals as a precursor to the later Users should follow all recommended constituents, the dissolved species in discussion of treatment options for safe-handling procedures and ven- the water will become progressively scale control. dor recommendations. Adherence to concentrated. As solubility limits be- A typical corrosion cell is shown in proper safe-handling guidelines, and come exceeded for calcium carbonate, Figure 1. As is true for all electrical the use of proper personal protective calcium sulfate, magnesium silicate, flow, a circuit must be established for equipment is essential, as many of the and other compounds, scale will form. the reaction to proceed. In this exam- aggressive treatment chemicals dis- The buildup of calcium phosphate ple, iron atoms give up two electrons cussed below will attack human cells, [Ca3(PO4)2] is also of concern in sys- at the anode and the atoms dissolve just as they attack the microbes they tems where phosphate or phospho- into the solution. are designed to kill. nates (organic phosphate compounds) 2Fe 2Fe+2 + 4e– (1) are used for scale and corrosion pre- Chemical treatment options vention. In fact, at one time calcium The electrons flow through the metal The discussion that follows focuses phosphate challenged calcium car- substrate to the cathode, where they on cooling tower systems that take bonate as the most prevalent scale- reduce a common species in the makeup from fresh water sources, forming substance in such systems, water. In typical neutral to alkaline such as lakes, rivers, groundwater, or because calcium phosphate deposits cooling waters, the primary reactant municipal water supplies. The vast can be very heavy and insulating. is oxygen. majority of the 300,000 or more cool- Many modern chemistry programs O2 + 2H2O + 4e– 4OH– (2) ing towers operating in the U.S. today operate under alkaline conditions, to CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009 43
- 50. Operations & Maintenance Theions formed at the anode and cathode migrate toward each other, OH OH PO3H2 completing the circuit. The overall cor- P P CH2 C CH2 CH2 rosion reaction is: O O OH OH OH COOH COOH COOH 2Fe + O2 + 2H2O 2Fe(OH)2 (3) Ferrous hydroxide [Fe(OH)2] will FIGURE 2. Two commonly used phosphonates (shown here) are 1-hydroxyeth- ylidene-1,1-diphosphonic acid (HEDP) and 2-phosphono-butane-1,2,4-tricarboxylic further oxidize to ferric hydroxide acid (PBTC). Phosphonates help to inhibit the formation of calcium-based scale in [Fe(OH)3] and eventually turn to rust cooling water systems (Fe2O3 2O). Water-treatment programs that However, acid feed alone may not course reduce the effectiveness of the slow down either the anodic or ca- eliminate scaling. Upsets of acid feed phosphonates, and will also increase thodic reactions, or both, will reduce systems can lead to corrosion or scal- the orthophosphate concentration and the corrosion rate. (Note: Anodic in- ing, and sulfuric acid introduces sul- the potential for the deposition of cal- hibitors, if not carefully monitored for fate ions (SO4–2) to the water, which cium phosphate. residual chemical levels, can lead to may in turn lead to calcium sulfate A common phosphonate treatment the formation of a few anodic sites in a deposition. Accordingly, supplemen- program might include one or perhaps large cathodic field. Quick and damag- tal chemicals are normally employed two of the phosphonate compounds, ing pitting is then likely to occur.) in cooling tower programs to further used in relatively low-mg/L dosages Just a few decades ago, a very com- minimize scale formation. for primary scale control. For instance, mon treatment program for cooling One common treatment method dosages as low as 5 mg/L of orthophos- towers was to use sulfuric acid injec- was the use of phosphates, either phate can be used for additional scale tion (to remove bicarbonate ions and ortho-phosphate (PO4–2) or phosphate control and corrosion protection, and minimize calcium carbonate scaling complexes, that would revert to ortho- zinc can be used in dosages as low as potential) combined with chromate phosphate, to precipitate calcium as 0.5 to 2.5 mg/L (zinc dosage is temper- (CrO4–2) feed. These chromate-based, calcium phosphate [Ca3(PO4)2]. These ature-dependent). Zinc reacts with the pH-adjustment programs were very programs also provided corrosion pro- hydroxyl ions generated at cathodes effective and generally made life easy tection because phosphate will react to form a precipitate [Zn(OH)2], which for the cooling water chemist. Chro- with ferrous ions (Fe+2) produced at provides additional cathodic protec- mate establishes a protective surface anodic sites to form a protective bar- tion. Also typically included in this for- coating that resembles stainless steel. rier, while calcium phosphate precipi- mulation is a small dose of an organic However, the toxicity of chromate tates in the local alkaline environment polymer for control of calcium phos- has led to severe restrictions on the at cathodic sites. phate deposition. use of this chemical, so modern treat- However, even small upsets in Original polymers developed for ment programs have generally evolved phosphate programs can cause se- these applications contain carboxylic into alternative, non-chromate meth- vere calcium phosphate fouling. Ac- acid functional groups (COOH), where ods that operate at a mildly alkaline cordingly, treatment methods have the negatively charged oxygen atoms pH. Operation at alkaline pH itself evolved to more-forgiving methodolo- bind with calcium to modify crystal helps to reduce corrosion, but higher gies, where in many cases the back- growth. More advanced compounds, pH increases the potential for scale bone of these programs is still an such as terpolymers, have a structure formation, particularly from calcium organic phosphate (a phosphonate) that includes carboxylic, amide (R- carbonate and calcium phosphate. that is used in conjunction with a CO-NH2), and sulfonic acid (SO3H) Consider the following example of supplemental polymer to sequester groups for improved reactivity and untreated water in the cooling system. and modify the crystal structure of resistance to degradation. However, As the water is cycled, the first com- scale-forming ions and compounds zinc, like many other metals, is falling pound that tends to come out of solu- (Figure 2). In essence, phosphonates under tighter regulatory guidelines, so tion is calcium carbonate. attach to deposits as they are form- zinc may no longer be acceptable as an ing and disrupt crystal growth and additive in many locations. Ca+2 + 2HCO3– + heat CaCO3 + lattice strength. One program that has gained much CO2 + H2O (4) Careful monitoring and control popularity in recent years is based A straightforward and often-used of phosphonate programs is still re- upon the use of a phosphino succinic method to reduce the potential for cal- quired, as overfeed of phosphonates oligomer (PSO) with a supplemental, cium carbonate scaling is to treat the can lead to calcium-phosphonate de- but slight, orthophosphate dosage and makeup with sulfuric acid (H2SO4), position. Conversely, phosphonates a polymer to inhibit calcium phos- where the hydrogen ions (H+) from the exhibit varying degrees of susceptibil- phate deposition. The PSO molecules acid convert the bicarbonate to carbon ity to degradation from thermal and contain both phosphate-oxygen and dioxide (CO2). The gas exits from the chemical stresses, where oxidizing bi- carboxylic functional groups. cooling tower. ocides in particular may cause compo- One complicating factor of the nent breakdown. Degradation will of above-mentioned programs is that at H+ + HCO3– CO2 + H2O (5) 44 CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009
- 51. SPX Cooling Technologies CH3 N N N N N N FIGURE 4. Cooling water towers H H are typically equipped Benzotriazole Tolyltriazole with a high-surface-area fill to promote heat transfer and cooling. Unless the water FIGURE 3. Shown here are the basic structures of is properly treated, the intricate benzotriazole and tolyltriazole. The plate-like structure surface area of this fill is subject of the organic rings help these compounds to form a to fouling and scale build-up protective surface layer on metal components during operation some locations, phosphate-containing ownstream nasty, as they will foul downstream chemicals for cooling-water treat- ters. equipment, most notably filters. Other ment are banned, as they provide a airborne contaminants can cause sim- i potent nutrient for vegetative growth. ilar problems (Figure 4). saccharide layer for self-protection. No doubt many readers are aware of Suspended solids will naturally be- This film will accumulate silt from the algae blooms, which can seriously come concentrated in the system and water, growing even thicker and fur- disrupt surface water chemistry and settle in and on heat exchanger tubes, ther reducing heat transfer at those kill aquatic life. For cooling tower ap- reducing their heat transfer efficiency. surfaces. Even though the bacteria at plications, treatment programs are One of the most common methods to the surface may be aerobic, the secre- available or are being further devel- remove these foulants is via continu- tion layer allows anaerobic bacteria to oped in which scale control is main- ous, side-stream filtration, where a flourish underneath. These microbes tained with polymers that contain slipstream is routed through a me- in turn can generate acids and other no phosphorous. chanical filter. The flowrate through harmful compounds that directly at- In systems that have copper alloy the filter can be as low as 1 to 5 vol.% tack the metal. heat exchanger tubes (often referred of the total cooling water flow, as even Microbial deposits also establish to as yellow metal components), the this fractional rate will help to reduce concentration cells, where the lack of treatment program should include an the solids buildup in the system. oxygen underneath the deposit causes azole. Tolyltriazole and benzotriazole the locations to become anodic to other have been the most commonly used, Microbiological control areas of exposed metal. Pitting often but others are evolving (Figure 3). The management of microbiological results. A low dosage of triazoles (on the fouling presents another challenge for Meanwhile, fungi will attack cooling order of 2–3 mg/L) is typically required cooling-water systems. By their very tower wood in an irreversible manner for corrosion control. The most widely nature, water-based cooling systems — in some cases, leading eventually to accepted theory regarding the protec- provide an ideal environment — warm structural failure. Algae will also foul tion mechanism is that the nitrogen and wet — for microbes to flourish. cooling tower spray decks, potentially in the triazoles bonds with copper to Unless properly controlled through leading to reduced performance and form a plate-like molecular layer at the use of biocides, bacteria will grow unsafe working conditions. the metal surface. Once this occurs, in condensers and cooling-tower fill, At the heart of any microbiologi- the azoles prevent the penetration of fungi will flourish on and in cooling- cal treatment program is the use of corrosive species. tower wood, and algae will grow on an oxidizing biocide to kill organisms Tolyltriazole, while being the least wetted tower components that are ex- before they can settle on condenser expensive of this family of compounds, posed to sunlight. Thus, biocide use is tube walls, cooling tower fill and is also the most subject to decomposi- absolutely essential to maintain sys- other locations. tion by oxidizing biocides. Benzotri- tem performance and integrity. Chlorine has been the workhorse azole is a common replacement, but In general, three different types of biocide for many years. When gaseous newer halogen-stable azoles are also bacteria must be controlled: chlorine is added to water, the follow- gaining in popularity. These com- Aerobic bacteria: Utilize oxygen in ing reaction occurs: pounds include an extra organic side the metabolic process Cl2 + H2O HOCl + HCl (6) chain attached to the fused benzene Anaerobic bacteria: Live in oxygen- ring. They are more expensive than free environments and rely on other In this case, HOCl (hypochlorous acid) the basic azoles, but greater stability sources (such as sulfates, nitrates, is the killing agent. The functionality and longer residence times can make or other donors) for their energy and killing power of this compound them cost-effective in the long run. supply are greatly affected by pH due to the Cooling towers are very efficient air Facultative bacteria: Can live in equilibrium nature of HOCl in water. scrubbers, as the circulating water in- either aerobic or anaerobic HOCl H+ + OCl– (7) side the tower will capture dust and environments many other airborne contaminants. A big problem with bacterial growth OCl– (the hypochlorite ion) is a much From personal experience I know that is that once the microbes settle on a weaker biocide than HOCl, probably cottonwood seeds can be particularly surface, the organisms secrete a poly- due to the fact that the charge on CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009 45
- 52. 100 0 80 20 Operations & Maintenance Percent ionized Percent acid 60 40 HOCl HOBr 40 60 the OCl– ion does not allow it to pen- FIGURE 5. In this com- parison of HOCl versus etrate bacterial cell walls. The killing HOBr dissociation, note 20 80 efficiency of chlorine dramatically that the dissociation of declines as pH goes above 7.5. Thus, HOCl occurs at a signifi- 0 100 for the common alkaline scale and cor- cantly lower pH compared 4 5 6 7 8 9 10 11 pH rosion treatment programs — which to that of HOBr intentionally maintain pH above 7 TABLE 2. NON-OXIDIZING BIOCIDES — chlorine chemistry may not be ef- ficient. Chlorine demand is further Chemical Advantages Disadvantages affected by ammonia or amines in the 2,2,-dibromo-3- Fast acting, effective against Expensive, degrades water, which react irreversibly to form nitrilopro- bacteria, degrades quickly to quickly above pH 9, not the much less-potent chloramines, the pionamide non-hazardous byproducts. very effective against (DBNPA) fungi and algae. primary example being monochloro- amine (NH2Cl). Glutaraldehyde Effective at high pH, effective Degraded by oxidizing against bacteria. biocides. Due to safety concerns, liquid bleach (NaOCl) feed has replaced gaseous Isothiozoline Effective against bacteria and Skin sensitizer. chlorine at many facilities. The major fungi. Works well with oxidiz- ing biocides. Active over a difficulty with using bleach is that wide pH range. the typical industrial-grade bleach Quaternary Effective against all organisms Can cause foaming. contains small amounts of sodium hy- amines depending upon functional Careful handling re- droxide. Thus, when it is injected into groups attached. quired. the cooling-water stream it raises the Active over a wide pH range. pH, if by only a small amount. A popular alternative is bromine Other oxidants that have been improper monitoring and manage- chemistry, where a chlorine oxidizer tested for cooling water include hydro- ment of process chemistry engender and a bromide salt, typically sodium gen peroxide (H2O2) and ozone (O3), excessive costs with regard to reduced bromide (NaBr), are blended in a but the short lifespan and tendency heat transfer efficiency [2], but pip- makeup water stream and injected of these chemicals to escape from so- ing and steam-generator tube failures into the cooling water. The chemistry lution in the cooling tower typically can also increase maintenance-related produces hypobromous acid (HOBr), make them ineffective in large cool- costs and may even lead to unsched- which has similar killing powers to ing-water systems. uled process shutdowns, leading to ad- HOCl, but functions more effectively Another method to help control ditional cost escalations. ■ at alkaline pH. microbes is a supplemental feed of a Edited by Suzanne Shelley Another factor in favor of bromine is non-oxidizing biocide. Typically, feed that it does not react irreversibly with is needed on a temporary but regular References ammonia or amines. However, the pri- basis, perhaps once per week. Table 2 1. Buecker, B., CPI water and steam chemistry, Chem. Eng., Vol. 115, No. 2, February 2008, mary disadvantages of bromine use summarizes some of the properties of pp. 30-34. are that an extra chemical is needed, the most common non-oxidizers. 2. Buecker, B., Steam generation thermody- and feed systems are a bit more com- Careful evaluation of the microbial namics 101, Power Engineering, Vol. 112, No. 11, November 2008, pp. 106–114. plex than for bleach alone. species in the cooling water is neces- Chlorine dioxide (ClO2) has found sary to determine the most effective Author some application as an oxidant for biocides. From personal experience, I Brad Buecker is the tech- two primary reasons. Its killing power have seen very positive results with nical support specialist is not affected by pH, and it does not DBNPA on lake water supplies, but with AEC PowerFlow (3125 Roanoke Road, Kansas City, form halogenated organic compounds. this chemical should not be considered MO 64111; Phone: 816- 531-3800; Email: bbuecker@ Also, chlorine dioxide is more effective a universal killing agent. Also, none aecpowerflow.com). Previ- in attacking established bio-deposits. of these chemicals should be used or ously, he served as an air- quality control specialist and However, ClO2 is unstable and thus tested without appropriate regula- plant chemist for Kansas must be generated onsite. A common tory approval. They must fit in with City Power & Light. He also has experience as a chemical method for onsite generation is the the plant’s National Pollutant Dis- cleaning services engineer, water and wastewa- reaction of sodium chlorite (NaClO2) charge Elimination System (NPDES) ter system supervisor, and consulting chemist for Burns & McDonnell Engineers. Earlier in and chlorine in a slipstream fed to the or equivalent guidelines. his career, Buecker served as a results engineer, fluegas desulfurization (FGD) engineer, and an- cooling water, which proceeds as: alytical chemist for City Water, Light & Power 2NaClO2 + Cl2 2ClO2 + 2NaCl (8) Closing thoughts (Springfield, Ill.). Buecker has written many articles on steam generation, water treatment, As discussed in an earlier article by and FGD chemistry, and he is the author of three Costs are usually several times higher this author [1], CPI technical personnel books on steam generation topics, published by PennWell Publishing (Tulsa, Okla.). He holds an due to the fact that more chemicals sometimes focus on process chemistry A.A. in pre-engineering from Springfield College are required with onsite production without properly monitoring water/ in Illinois, and a B.S. in chemistry from Iowa State University. He is a member of the ACS, than for straight halogen treatment. steam chemistry closely. Not only can AIChE, ASME, and NACE. 46 CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009
- 53. Hamworthy Peabody Combustion FOCUSON Boilers & Steam Handling These new resins are an alterna- tive to metal boiler components In wall-hung condensing boilers for resi- dential use, high-performance Noryl, the self-cleaning, low-main- Ultem and Cycoloy resins can replace tenance Chentronics’ High traditional metals such as copper and Energy Direct Spark Ignitor. brass used in boiler components, includ- The ECOjet’s staged gas de- ing condenser housings and manifolds. sign provides extremely sta- In high-efficiency condensing boilers, ble flames, up to 20:1 burner Noryl PPX resin offers an advantage over turndown, hot standby, stainless-steel condenser housings for its available continuous pilot, chemical resistance and ability to with- and precise furnace warm- stand the required heat from the con- up. It offers ultra-low NOx denser. Boiler manifolds are traditionally on a full range of gaseous made of copper tubing and brass parts, fuels (natural gas, propane, but upgrading to Noryl glass-filled resin refinery gas, landfill gas or Ultem resin may allow manufacturers and off gasses). Low NOx Sussman Electric Boilers to consolidate parts, reduce weight, and emissions are offered on all save on fabrication and assembly costs. liquid fuels (No. 2 through A third application is the boiler control No. 6 fuel oil, and ultra- panel cover and enclosure components, ring, and adjusts treatment accordingly. heavy fuels, such as pitch and bitumen). typically made of painted sheet metal. — Nalco, Naperville, Ill. The ECOjet is applicable to package, in- Flame-retardant Cycoloy resins offer www.nalco.com dustrial, and utility boilers ranging from excellent aesthetics and surface finishes single to multi-burner wall-fired, turbo, combined with high-flow properties to Ultra-high efficiency condensing and other boiler types. The unit features mold thin-wall parts. — Sabic Innovative boilers for tough conditions capacities to 400-mil. Btu/h. — Hamwor- Plastics, Pittsfield, Mass. The Triple-Flex Ultra-High Efficiency thy Peabody Combustion Inc. www.sabic-ip.com Condensing “Flexible Water Tube” Boilers www.hamworthyengineering.com (photo, p. 48) offer a guaranteed minimum Detect variability in boiler opera- thermal efficiency of 90% in worst-case Position sensors provide feed- tion for improved efficiency condensing boiler operating conditions back of steam control valves The 3D Trasar Boiler Technology detects (such as 160°F return water and 180°F This high-temperature and mild radi- system variability, then determines and supply water at 100% firing load). Efficien- ation-resistant series of linear position delivers the appropriate automated re- cies of 99% are achievable with lower re- sensors is designed for use in the position sponse before problems occur. Operat- turn-water temperatures. The Triple-Flex measurement of nuclear steam and gas ing boiler systems more efficiently saves boilers fire at 3,000,000 Btu input, with turbine control valves within power gen- water, energy and associated costs, while less than 30 ppm NOx levels, utilizing a eration plants. Constructed of stainless preserving and extending the life of costly hybrid metal fiber 5:1 turndown burner, steel, the HSTAR 750 Series hermetically equipment. Under manual alternatives, and Honeywell SOLA hydronic safety con- sealed position sensors can withstand variations in the water used and in the trols and interface systems. Other features 400ºF temperature spikes and exposure steam load requirements for a boiler sys- include easily replaceable stainless-steel to radiation at 3∙107 Rads for 40 years. tem make the overfeeding or underfeed- flexible tubes, a variable speed combustion These ¾-in.-dia., a.c.-operated linear po- ing of water-treatment chemistry com- air blower and easy-to-remove access pan- sition sensors are being implemented in monplace. Realtime sampling of system els that make the boiler interior accessible the rehabilitation of power generation conditions are uncommon because of the for both service and inspection. — Bryan plants to better monitor the position of high temperatures involved, and pressure Steam LLC, Peru, IN controls for increased efficiency and re- and other conditions can’t be replicated www.bryanboilers.com duced operating costs. Operating within outside the boiler system itself. 3D Trasar the harsh environment of a power or Boiler Technology combines advanced This burner offers ultra-low steam plant, the HSTAR position sen- sensors, chemistry, software and control NOx emissions sors provide highly accurate feedback of equipment to provide the opportunity to The ECOjet burner (photo) offers ultra- valve position, providing output to remote understand exact conditions in the boiler low emissions with little or no flue gas electronics that can be monitored by op- and steam system when they are occur- recirculation. Ignition is achieved using erators. Available in ranges of ±0.050 to Note: For more information, circle the 3-digit number CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009 47 on p. 54, or use the website designation.
- 54. Electro-Chemical Devices Focus BryanSteam ±10.0 in., sensors feature high resolution, humidifier and sterilization. Electric Mini-MOD-CNC will use the condensing excellent repeatability, low hysteresis and stainless-steel boilers are ideal for clean boiler group as the lead group, switching the highest sensitivity consistent with steam in that they can be located near the to the non-condensing group after the good linearity, according to the company. process, thereby reducing contamination system temperature rises above the sys- — Macro Sensors, Pennsauken, N.J. introduced by steam piping. The satu- tem switching set point. For the modu- www.macrosensors.com rated steam from the boilers can be con- lating group of boilers, an advanced PID trolled as to pressure, which will vary the logic has been used to provide modulation For small-scale applications, temperature and energy transfer of the that can fit most applications, whether use this steam generator steam. The unit offers 1.5–120 kW power the boilers are to sequence normally, one MBA Electric Steam Generators (photo, p. to match the needs of any pure steam ap- after the other, or in parallel. — Heat- 47) are ideal for small-scale applications plication. Multiple boilers can be stacked Timer Corp., Fairfield, N.J. that require high-quality steam. These for larger applications. A 304-stainless- www.heat-timer.com generators can be used for standby op- steel pressure vessel is standard, with erations in off-seasons, or when a larger 316 stainless steel available. Passivation This automated blowdown sys- boiler is shut down or unavailable. The of the pressure vessel and heating ele- tem improves boiler efficiency automatic electronic liquid-level control- ments is also standard. The boiler is de- With an intelligent controller design fea- ler meets all UL and ASME requirements. signed and constructed to Section I, Parts turing PID output, the Model 61 Boiler A main waterline pressure 10 psig greater PMB & PEB of the ASME Boiler Code. — Blowdown System (photo) modulates the than the operating pressure of the steam Reimers Electra Steam, Clear Brook, Va. blowdown control valve to allow the maxi- generator is required for automatic water www.reimersinc.com mum level of dissolved solids. Conductiv- feeding. The MBA Series generators pro- ity (TDS) sensors are utilized to determine vide a safe, easy-to-use heat source free Simultaneously control condens- when the boiler water must be replaced. of onsite products of combustion. Easy ing and non-condensing boilers The conductivity measurement is made and quick to install, they require only The Mini-MOD-CNC is has the capabil- with the controller or optional two-wire a water feed connection and electrical ity to lead-lag two different groups of transmitters (Model T23 or T28) and the hook-up. Applications include: laboratory boilers: condensing and non-condensing. Model CS10. The standard conductivity use, steam for small tanks, reactions and The controller provides two means of se- (TDS) range of the Model 61 BBS CS10 distillations, autoclaves, food products, lecting the lead group switching, either sensor is 0 –10,000 μS. It operates over a jacketed vessels for processing waxes, using a specific system or outdoor set temperature range from 0 to 100°C under paraffins, glues, resins and varnishes and point with an adjustable switching delay. pressures from 0 to 75 psig. The Model 61 woodbending. — Sussman Electric Boil- If using the outdoor temperature as the BBS features a Model C22 Controller, a ers, Long Island City, N.Y. switching mechanism, and it is above the line powered instrument with PID control www.sussmanboilers.com set point, the Mini-MOD-CNC will use functions, logic functions and timers. The the condensing boiler group as the lead standard Model 61 is supplied with one These stainless-steel boilers are group, switching to the non-condensing 4–20-mA output and two alarm relays. Up ideal for clean steam applications group after the outdoor temperature to four outputs and eight relays are avail- These stainless-steel electric steam boil- drops below the outdoor switching set able. — Electro-Chemical Devices, Inc., ers are suitable for ultra-pure applica- point. When using the system tempera- Yorba Linda, Calif. tions, including: autoclaves, cosmetics, ture set point as the switching mecha- www.ecdi.com medical research, pharmaceutical, pure nism, and it is below the set point, the Kate Torzewski 48 CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009
- 55. PRODUCT SHOWC ASE Protect pressure or vacuum instruments from clogging, corrosion and damage. Compact and Economical, Plast-O-Matic Gauge Guards prevent dangerous leaks and allow dependable instrument readings from full vacuum to 250 psi. PTFE or FKM diaphragms. PVC, Polypro or PVDF bodies. vailable with or without gauges. Gauge Shields for harsh environments. PLAST-O-MATIC VALVES, INC. Circle 201 on p. 54 or go to Circle 202 on p. 54 or go to Circle 203 on p. 54 or go to adlinks.che.com/23017-201 adlinks.che.com/23017-202 adlinks.che.com/23017-203 SOFTWARE CA Co PE-O mp PE lian N t! HTRI Xchanger Suite® – an integrated, easy-to-use suite of tools that Circle 241 on p. 54 or go to delivers accurate design calculations for adlinks.che.com/23017-241 CONSULTING Heat Transfer Research, Inc. HTRI@HTRI.net 150 Venture Drive www.HTRI.net College Station, Texas 77845, USA Circle 242 on p. 54 or go to Circle 240 on p. 54 or go to adlinks.che.com/23017-240 adlinks.che.com/23017-242 CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009 49
- 56. Intelligen Suite The Market-Leading Engineering Suite for Modeling, Evaluation, Scheduling, and Debottlenecking of Single & Multi-Product Facilities SuperPro SchedulePro R e cipe D B Use SuperPro Designer to model, evaluate, and Switch to SchedulePro to schedule, model, debottleneck batch and continuous processes and debottleneck multi-product facilities Tracking of equipment occupancy Tracking demand for resources Inventory tracking for raw materials, in multi-product facilities (e.g., labor, materials, utilities, etc.) intermediates, products, and wastes SuperPro Designer is a comprehensive process simulator that facilitates modeling, cost analysis, debottlenecking, cycle time reduction, and environmental impact assessment of biochemical, specialty chemical, pharmaceutical (bulk & fine), food, consumer product, mineral processing, water purification, wastewater treatment, and related processes. Its development was initiated at the Massachusetts Institute of Technology (MIT). SuperPro is already in use at more than 400 companies and 500 universities around the world (including 18 of the top 20 pharmaceutical companies and 9 of the top 10 biopharmaceutical companies). SchedulePro is a versatile finite capacity scheduling tool that generates feasible production schedules for multi-product facilities that do not violate constraints related to the limited availability of facilities, equipment, resources and work areas. It can be used in conjunction with SuperPro (by importing its recipes) or independently (by creating recipes directly in SchedulePro). Any industry that manufactures multiple products by sharing production lines and resources can benefit from the use of SchedulePro. Engineering companies use it as a modeling tool to size utilities for batch plants, identify equipment requirements, reduce cycle times, and debottleneck facilities. Circle 243 on p. 54 or go to adlinks.che.com/23017-243 Visit our website to download detailed product literature and functional evaluation versions of our tools Intelligen also has offices in Europe and representatives in countries around the world
- 57. NEW & USEDEQUIPMENT EquipNet.com/fmc +1.781.821.3482 Sales@EquipNet.com UNUSED-LOW TEMPERATURE-BATCH PROCESSING EQUIPMENT FROM FMC Equipment sized for Pilot to Small Scale Production 189377 - Unused 1995 Cogeim 1.0 Square Meter Hastelloy 189490 - Ward 500 Gallon Hastelloy C276 Reactor 188846 - Alloy Fabricators 250 Gallon Hastelloy C22 Reactor 189527 - Unused 200 Gallon Pfaudler Glass Lined Reactor 189010 - Unused 1995 Cogiem 0.6 Square Meter Hastelloy Nutsche Filter Circle 246 on p. 54 or go to adlinks.che.com/23017-246 Filter Presses WAT E R W O R K S 800.232.9334 219.663.8210 Clarifiers Sand Filters Tanks Pumps www.airtowater.com Filtration NEW USED SURPLUS Accessories Filtration Equipment Circle 247 on p. 54 or go to adlinks.che.com/23017-247 KILO LAB CENTRIFUGE HIGH SHEAR MIXERS World’s Widest Selection, Single Stage to Ultra High Shear! Circle 244 on p. 54 or go to adlinks.che.com/23017-244 1 ⁄2 -200 HP batch and inline Free trials in your plant GET CONNECTED TODAY ROUSSELET Ross will beat any major manufacturer’s quote! ROBATEL www.che.com 1-800-243-ROSS Phone: 413.499.4818 Fax: 413.499.5648 USA Tel: 631-234-0500 Fax: 631-234-0691 email: sales@robatel.com www.rousselet-robatel.com/che09 www.highshearmixers.com Circle 248 on p. 54 or go to Circle 249 on p. 54 or go to adlinks.che.com/23017-248 adlinks.che.com/23017-249 To Advertise in the Buyers' Guide Contact Helene Hicks Buyers' Tel: 212-621-4958 Fax: 212-621-4976 Guide 2010 Email: hhicks@che.com Circle 245 on p. 54 or go to adlinks.che.com/23017-245 CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009 51
- 58. NEW & USEDEQUIPMENT PROCESS & MACHINERY Wedge-Wire Screen Manufacturer: FILTER PRESSES CONTROL filtration screens, resin traps, strainer Shriver JWI Komline Sperry baskets, hub and header laterals, media ABB/BAILEY retention nozzels, and custom filtration Recessed and Plate & frame designs INFI90TM/NETWORK90TM products manufactured with stainless SymphonyTM steel and special alloys. PARTS SERVICE CENTER FOXBORO Contact: Jan or Steve Plates: Poly Alum & CI I/A SeriesTM 18102 E. Hardy Rd., Houston, TX 77073 Filter cloth and paper Cost-effective replacement, repair, and Ph: (281) 233-0214; Fax: (281) 233-0487 Toll free: (800) 577-5068 Side bars Hydraulic cylinders repair/exchange of hard-to-find DCS parts. ONE YEAR WARRANTY www.alloyscreenworks.com Avery Filter Company, Westwood, NJ Phone: 201-666-9664 Fax 201-666-3802 We also purchase surplus or E-mail: larry@averyfilter.com decommissioned DCS equipment. www.averyfilter.com (770)271-9932 www.pmcx.com Circle 252 on p. 54 or go to Circle 254 on p. 54 or go to Circle 250 on p. 54 or go to adlinks.che.com/23017-254 adlinks.che.com/23017-250 adlinks.che.com/23017-252 GET CONNECTED TODAY WABASH SELLS & RENTS Boilers 20,000 - 400,000 #/Hr. Advertise in www.che.com Diesel & Turbine Generators 50 - 25,000 KW Gears & Turbines the Classified 25 - 4000 HP We stock large inventories of: For more information on TOLL 24/7 Fast Emergency Service classified advertising, please contact: MANUFACTURING 800-704-2002 Phone: 847-541-5600 Fax: 847-541-1279 www.wabashpower.com Helene Hicks wabash POWER EQUIPMENT CO. Tel: 212.621.4958 444 Carpenter Ave., Wheeling, IL 60090 Fax: 212.621.4976 Circle 253 on p. 54 or go to adlinks.che.com/23017-253 email: hhicks@che.com DISTILLATION Circle 255 on p. 54 or go to adlinks.che.com/23017-255 Circle 251 on p. 54 or go to adlinks.che.com/23017-251 52 CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009
- 59. Advertisers’ Index Advertiser Page number Advertiser Page number Advertiser Page number Phone number Reader Service # Phone number Reader Service # Phone number Reader Service # A Box 4 U 15 Flexicon Corp 1 * Paharpur Cooling Towers 21 877-522-6948 adlinks.che.com/23017-13 adlinks.che.com/23017-04 91 33-4013 3000 adlinks.che.com/23017-14 * Alstom Power Inc 6 Flottweg 39 Rembe GmbH Safety + Control 6 877-661-5509 adlinks.che.com/23017-07 adlinks.che.com/23017-18 49 (0) 29 61 - 7405 - 0 adlinks.che.com/23017-08 Beumer Maschinenfabrik Heinkel USA 24D-3 GmbH & Co KG 11 856-467-3399 adlinks.che.com/23017-19 SRI Consulting 10 adlinks.che.com/23017-11 adlinks.che.com/23017-12 Honeywell Process Solutions 2 1-877-466-3993 adlinks.che.com/23017-05 Swagelok Co 4 Chevron THIRD COVER adlinks.che.com/23017-06 adlinks.che.com/23017-02 International Exposition Co 22 Trustchem Co Ltd 8 Dow High Temp SECOND COVER 203-221-9232 adlinks.che.com/23017-15 86-25-84729801 adlinks.che.com/23017-10 1-800-447-4369 adlinks.che.com/23017-01 ISA 25 Veolia Environment 7 * Endress + Hauser FOURTH COVER adlinks.che.com/23017-17 adlinks.che.com/23017-09 888-ENDRESS adlinks.che.com/23017-03 Load Controls Inc 24D-4 WEFTEC 24 888-600-3247 adlinks.che.com/23017-21 adlinks.che.com/23017-16 * Additional information in MB Industries 24D-2 Western States Machine Co 24D-4 2006 Buyers’ Guide 337-334-1900 adlinks.che.com/23017-20 adlinks.che.com/23017-22 See bottom of next page for advertising sales representatives' contact information Advertisers’ Classified Index - August 2009 (212) 621-4958 Fax: (212) 621-4976 Product Showcase . . . . . . . . . . 49 Send Advertisements and Box replies to: Helene Hicks, Chemical Engineering, 110 William St., 11th Floor, New York, NY 10038 Computer Software . . . . . . . . 49–50 Advertiser Page number Advertiser Page number Advertiser Page number Consulting . . . . . . . . . . . . . . . . .49 Phone number Reader Service # Phone number Reader Service # Phone number Reader Service # Equipment, Used or Charles Ross HFP Acoustical Process Machinery 52 Surplus New for Sale . . . . . . 51–52 & Son Company 51 Consultants 49 770-271-9932 Toll Manufacturing. . . . . . . . . . . .52 880-243-ROSS 888-789-9400 adlinks.che.com/23017-250 adlinks.che.com/23017-249 adlinks.che.com/23017-242 Robatel 51 Alloy Screen Works 52 CU Services 49 Indeck 50 413-499-4818 281-233-0214 847-439-2303 847-541-8300 adlinks.che.com/23017-248 adlinks.che.com/23016-252 adlinks.che.com/23017-202 adlinks.che.com/23017-244 Wabash Power AMISTCO 52 Equipnet 51 Intelligen 50 Equipment Company 52 281-331-5956 781-821-3482 908-654-0088 800-704-2002 adlinks.che.com/23017-255 adlinks.che.com/23017-246 adlinks.che.com/23017-243 adlinks.che.com/23017-253 Avery Filter Company 52 e-simulators 49 NATUREX 52 Water Works 51 201-666-9664 480-380-4738 201-440-5000 800-232-9334 adlinks.che.com/23016-254 adlinks.che.com/23017-241 adlinks.che.com/23017-251 adlinks.che.com/23017-247 BWB Technologies 49 Heat Transfer Reasearch, Inc.49 Plast-O-Matic Valves, Inc. 49 Xchanger Inc. 51 44--(0)1787-273-451 979-690-5050 973-256-3000 952-933-2559 adlinks.che.com/23017-201 adlinks.che.com/23017-240 adlinks.che.com/23017-203 adlinks.che.com/23017-245 MARCH, JUNE, SEPTEMBER & DECEMBER September Chemical Engineering is the preferred publication g among CHEM Show Attendees s Literature o enginee ing in o a ion n Reviews l co e age o he chemical ical al ocess ocess s Visit che.com e * The Wayman Group, 2007 CHEMshow survey The Wayman Group, 2007 CHEMshow survey Group CHEMshow survey to view online Plus more! Total Circulation: 65,837 al Domestic: 57,963 (BPA Audit January 2008) Contact: Helene Hicks 212-621-4958 hhicks@che.com for advertising information. Sept. closing: 8/6 CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009 53
- 60. New Product Information August 2009 JustFAXit! or go to www.che.com/adlinks Fill out the form and circle or write in the number(s) Go on the Web and fill out the below, cut it out, and fax it to 800-571-7730. online reader service card. Name Title Company Address City State/Province Zip/Postal Code Country Telephone Fax Email | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | FREE PRODUCT INFO 14 Engineering, Design & Construc- 29 10 to 49 Employees 47 Pollution Control Equipment (please answer all the questions) tion Firms 30 50 to 99 Employees & Systems 15 Engineering/Environmental Ser- 31 100 to 249 Employees 48 Pumps YOUR INDUSTRY vices 32 250 to 499 Employees 49 Safety Equipment & Services 01 Food & Beverages 16 Equipment Manufacturer 33 500 to 999 Employees 50 Size Reduction & Agglomeration 02 Wood, Pulp & Paper 17 Energy incl. Co-generation 34 1,000 or more Employees Equipment 03 Inorganic Chemicals 18 Other———————————— YOU RECOMMEND, 51 Solids Handling Equipment 04 Plastics, Synthetic Resins JOB FUNCTION SPECIFY, PURCHASE 52 Tanks, Vessels, Reactors 05 Drugs & Cosmetics (please circle all that apply) 20 Corporate Management 53 Valves 06 Soaps & Detergents 40 Drying Equipment 21 Plant Operations incl. Mainte- 54 Engineering Computers/Soft- 07 Paints & Allied Products 41 Filtration/Separation Equipment nance ware/Peripherals 08 Organic Chemicals 42 Heat Transfer/Energy Conserva- 22 Engineering 55 Water Treatment Chemicals 09 Agricultural Chemicals tion Equipment 23 Research & Development & Equipment 10 Petroleum Refining, 43 Instrumentation & Control Sys- 24 Safety & Environmental 56 Hazardous Waste Management Coal Products tems 26 Other———————————— Systems 11 Rubber & Misc. Plastics 44 Mixing, Blending Equipment 57 Chemicals & Raw Materials 12 Stone, Clay, Glass, Ceramics EMPLOYEE SIZE 45 Motors, Motor Controls 58 Materials of Construction 13 Metallurgical & Metal Products 28 Less than 10 Employees 46 Piping, Tubing, Fittings 59 Compressors 1 16 31 46 61 76 91 106 121 136 151 166 181 196 211 226 241 256 271 286 301 316 331 346 361 376 391 406 421 436 451 466 481 496 511 526 541 556 571 586 2 17 32 47 62 77 92 107 122 137 152 167 182 197 212 227 242 257 272 287 302 317 332 347 362 377 392 407 422 437 452 467 482 497 512 527 542 557 572 587 3 18 33 48 63 78 93 108 123 138 153 168 183 198 213 228 243 258 273 288 303 318 333 348 363 378 393 408 423 438 453 468 483 498 513 528 543 558 573 588 4 19 34 49 64 79 94 109 124 139 154 169 184 199 214 229 244 259 274 289 304 319 334 349 364 379 394 409 424 439 454 469 484 499 514 529 544 559 574 589 5 20 35 50 65 80 95 110 125 140 155 170 185 200 215 230 245 260 275 290 305 320 335 350 365 380 395 410 425 440 455 470 485 500 515 530 545 560 575 590 6 21 36 51 66 81 96 111 126 141 156 171 186 201 216 231 246 261 276 291 306 321 336 351 366 381 396 411 426 441 456 471 486 501 516 531 546 561 576 591 7 22 37 52 67 82 97 112 127 142 157 172 187 202 217 232 247 262 277 292 307 322 337 352 367 382 397 412 427 442 457 472 487 502 517 532 547 562 577 592 8 23 38 53 68 83 98 113 128 143 158 173 188 203 218 233 248 263 278 293 308 323 338 353 368 383 398 413 428 443 458 473 488 503 518 533 548 563 578 593 9 24 39 54 69 84 99 114 129 144 159 174 189 204 219 234 249 264 279 294 309 324 339 354 369 384 399 414 429 444 459 474 489 504 519 534 549 564 579 594 10 25 40 55 70 85 100 115 130 145 160 175 190 205 220 235 250 265 280 295 310 325 340 355 370 385 400 415 430 445 460 475 490 505 520 535 550 565 580 595 11 26 41 56 71 86 101 116 131 146 161 176 191 206 221 236 251 266 281 296 311 326 341 356 371 386 401 416 431 446 461 476 491 506 521 536 551 566 581 596 12 27 42 57 72 87 102 117 132 147 162 177 192 207 222 237 252 267 282 297 312 327 342 357 372 387 402 417 432 447 462 477 492 507 522 537 552 567 582 597 13 28 43 58 73 88 103 118 133 148 163 178 193 208 223 238 253 268 283 298 313 328 343 358 373 388 403 418 433 448 463 478 493 508 523 538 553 568 583 598 14 29 44 59 74 89 104 119 134 149 164 179 194 209 224 239 254 269 284 299 314 329 344 359 374 389 404 419 434 449 464 479 494 509 524 539 554 569 584 599 15 30 45 60 75 90 105 120 135 150 165 180 195 210 225 240 255 270 285 300 315 330 345 360 375 390 405 420 435 450 465 480 495 510 525 540 555 570 585 600 If number(s) do not appear above, please write them here and circle: Fax this page back to 800-571-7730 ADVERTISING SALES REPRESENTATIVES Mike O’Rourke, Publisher North America George Gortz, Helene Hicks, Chemical Engineering Jason Bullock, District Sales Manager Inside Sales Manager 110 William St., New York, NY 10038-3901 District Sales Manager Chemical Engineering Chemical Engineering; Tel: 215-340-1366; Fax: 609-482-4146 Chemical Engineering 2612 Edgerton Road 110 William St., New York, NY 10038-3901 E-mail: morourke@che.com 8325 Broadway, Ste. 202/PMB 261 University Heights, OH 44118 Tel: 212-621-4958; Fax: 212-621-4976; Alabama, Canada, Connecticut, Delaware, Pearland, TX 77581 Tel: 216-932-2700; Fax 216-932-5810 E-mail: hhicks@che.com Florida, Maine, Maryland, Massachusetts, Tel: 281-485-4077; Fax: 281-485-1285 E-mail: ggortz@che.com Product Showcase, Literature Reviews, New Hampshire, New Jersey, New York (minus E-mail: jbullock@che.com; Indiana, Illinois, Iowa, Kentucky, Classified Display Advertising Western New York), North & South Carolina, Arkansas, Arizona, California, Michigan, Minnesota, Ohio, Western Alaska, Hawaii, Idaho, Mississippi, Pennsylvania (minus Western Pennsylvania), Colorado, Georgia, Kansas, New York, Western Pennsylvania, Montana, Nebraska, New Mexico, Rhode Island, Tennessee, Vermont, Virginia, Louisiana, Missouri, Nevada, Wisconsin North & South Dakota, Oregon, Utah, Washington, D.C., West Virginia, Latin America Oklahoma, Texas Washington, Wyoming International Dipali Dhar Ferruccio Silvera Rudy Teng Chemical Engineering Chemical Engineering Chemical Engineering Petra Trautes 110 William St., New York, NY 10038-3901 Silvera Pubblicita Professional Publication Agency Chemical Engineering Tel: 212-621-4919; Fax: 212-621-4990 Viale Monza, 24 Milano 20127, Italy 6F-3 # 103 Fen Liau St Neihu Zeilweg 44 E-mail: ddhar@chemweek.com Tel: 39-02-284-6716; Fax: Taipei 114 Taiwan D-60439 Frankfurt am Main India 39-02-289-3849 Tel: 886-2-2799-3110 ext 330; Germany E-mail: ferruccio@silvera.it/www. 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- 61. Economic Indicators BUSINESS NEWS closure of one polystyrene plant at its Lud- the acquisition of Henogen, a contract PLANT WATCH wigshafen site.The plant, which has been manufacturing organization offering bio- Dow plans to shut down its ethylene oxide out of operation since mid-April, will be process development and manufacturing and glycol plant in the U.K... dismantled.This closure will reduce BASF’s services from the cell bank to the supply July 08, 2009 — The Dow Chemical Co. (Mid- polystyrene production capacity in Europe of clinical products. Financial terms of the land, Mich.) has announced its intention to by 80,000 m.t./yr to 540,000 m.t./yr or about transaction were not disclosed. close its ethylene oxide and glycol (EOEG) 15%.The main reason for the shutdown is a production facility at Wilton, U.K. by the end decrease in demand. BASF reorganizes its of January 2010. Several factors contribute Petrochemicals Division to the decision, including the site’s disad- Lanxess postpones Singapore July 1, 2009 — BASF SE (Ludwigshafen, Ger- vantaged input costs. In addition, demand production until 2014 many) has reorganized its Petrochemicals and profit margins for the site’s outputs, June 29, 2009 — Due to the continuing glob- Division. In the new organization, the num- particularly monoethylene glycol (MEG), al economic crisis, Lanxess AG (Leverkusen, ber of business units has been reduced began to soften in early 2008. Germany) is postponing the construction from six to four.The new business unit Basic of its new butyl rubber facility in Singapore. Petrochemicals Europe, headed by Dr.Uwe … and increases PP catalyst capacity in Production is now scheduled to start in 2014. Kirchgäßner, comprises the businesses for Louisiana… The 100,000-ton/yr plant, which would have cracker products and industrial gases as July 7, 2009 — Dow Basic Plastics Licensing cost up to 400 million to build, had been well as alkylene oxides and glycols in Eu- and Catalyst has increased capacity at its due onstream in 2012. rope. More details of the reorganization can SHAC Catalyst plant in Norco, La. by 20%. be found on www.che.com. SHAC catalysts are used in polypropylene SNF plans new polymers plant (PP) production and are the preferred cata- in Louisiana Celanese unveils EVA Performance lyst for licensees of the UNIPOL Technology. June 25, 2009 — SNF Holding Co. (Riceboro, Polymers Business Unit Ga.) has announced its plans to construct June 26, 2009 — Celanese Corp. (Dallas, Borouge is expanding a new facility for the manufacture of water- Tex.) has announced that it will rename polyolefins production soluble polymers in Iberville Parish, La.The its AT Plastics Inc. business, a producer of July 6, 2009 — Borouge, a joint venture be- proposed facility is expected to be built in ethylene vinyl acetate (EVA) copolymers tween the Abu Dhabi National Oil Co. (Abu phases over five years, with a total capital and low density polyethylene (LDPE) resins, Dhabi, U.A.E.), and Borealis (Vienna, Aus- investment of approximately $350 million. Celanese EVA Performance Polymers Inc. tria), is expanding its production capacity of The initial target capacity is 250,000 ton/yr The name change was expected to occur polyolefins in Abu Dhabi to 4.5 million metric of polyacrylamide. Construction will begin on Aug. 1, 2009.The Celanese EVA Perfor- tons per year (m.t./yr) by the end of 2013. after the company has secured the neces- mance Polymers business includes traditio- Borouge has awarded the three main con- sary regulatory permits, and the company nal applications for EVA copolymers and tracts for the front-end engineering and de- is hopeful that a 1st Q 2010 construction LDPE resins, including flexible packaging, sign (FEED) stage of its Borouge 3 expansion startup is attainable, with a plant startup lamination products, hot melt adhesives, in Ruwais, Abu Dhabi to Tecnimont (Maire expected to occur approximately one year medical tubing and automotive parts. Tecnimont Group, Rome, Italy).This includes after construction begins. Emerging markets for EVA copolymers the FEED of the multiple polyolefin units, the include pharmaceutical and medical LDPE (low density polyethylene) unit and the products, the solar energy industry and utilities and offsite facilities. MERGERS AND ACQUISITIONS agricultural applications. Rhodia enters into the Topsøe contracts the world’s biogas market Honeywell plans to acquire largest ammonia plant July 6, 2009 — Rhodia (Paris) has an- the RMG Group July 2, 2009 — Haldor Topsøe A/S (Lyngby, nounced its first business development in- June 26, 2009 — Honeywell (Morristown, Denmark) will supply ammonia synthesis vestment in biogas technology, by acquiring N.J.) has signed a definitive agreement technology to Perdaman Chemicals and Econcern Group’s participation in six pilot- valued at approximately $400 million to Fertilizers (Perth, W. Australia). With a capac- scale biogas-production projects located in acquire the Kassel, Germany-based RMG ity of more than 3,500 m.t./d, this ammonia China and Vietnam.The effective comple- Group (RMG Regel + Messtechnik GmbH plant will be the world’s largest.The ammo- tion of the transaction is subject to certain and all of its subsidiaries, together RMG). nia synthesis loop will be part of Perdaman’s closing conditions, including approval by RMG will be integrated into Honeywell Pro- A$3.5-billion Collie Urea Project to develop the relevant antitrust authorities. It is expect- cess Solutions.The transaction is subject to a plant in W. Australia that will transform sub- ed to be finalized in the 4th Q of 2009. regulatory approvals. RMG specializes in bituminous coal into urea.The urea plant’s the design and manufacture of natural gas capacity will be 2-million m.t./yr of urea, with Novasep adds upstream processing control, measurement and analysis equip- a scheduled startup in 2013. capabilities through Henogen acquisition ment including flow metering technology, July 2, 2009 — Novasep (Pompey, France), a regulating products and safety devices for BASF to reduce polystyrene producer of active pharmaceutical ingredi- oil and gas companies and has estimated capacity in Europe ents (APIs) and purification technologies for 2009 sales to be $290 million. June 30, 2009 — BASF has announced the the life science industries, has announced Dorothy Lozowski FOR ADDITIONAL NEWS AS IT DEVELOPS, PLEASE VISIT WWW.CHE.COM August 2009; VOL. 116; NO. 8 Chemical Engineering copyright @ 2009 (ISSN 0009-2460) is published monthly, with an additional issue in October, by Access Intelligence, LLC, 4 Choke Cherry Road, 2nd Floor, Rockville, MD, 20850. Chemical Engineering Executive, Editorial, Advertising and Publication Offices: 110 William Street, 11th Floor, New York, NY 10038; Phone: 212-621-4674, Fax: 212-621-4694. Subscription rates: $59.00 U.S. and U.S. possessions, Canada, Mexico; $179 International. $20.00 Back issue & Single copy sales. Periodicals postage paid at Rockville, MD and additional mailing offices. Postmaster: Send address changes to Chemical Engineering, Fulfillment Manager, P Box 3588, Northbrook, .O. IL 60065-3588. Phone: 847-564-9290, Fax: 847-564-9453, email: clientservices@che.com. 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- 62. Economic Indicators 2009 2008 DOWNLOAD THE CEPCI TWO WEEKS SOONER AT WWW.CHE.COM/PCI CHEMICAL ENGINEERING PLANT COST INDEX (CEPCI) 650 (1957-59 = 100) May. '09 Apr. '09 May. '08 Prelim. Final Final Annual Index: CE Index 509.2 511.7 583.9 2001 = 394.3 600 Equipment 596.8 600.4 710.3 Heat exchangers & tanks 529.9 534.2 712.4 2002 = 395.6 Process machinery 583.2 584.9 644.3 2003 = 402.0 550 Pipe, valves & fittings 748.1 752.5 835.6 2004 = 444.2 Process instruments 389.0 390.1 445.6 2005 = 468.2 500 Pumps & compressors 896.7 897.5 862.1 Electrical equipment 458.9 460.2 453.8 2006 = 499.6 Structural supports & misc 602.4 609.0 770.6 450 Construction labor 326.9 326.5 319.7 2007 = 525.4 Buildings 485.4 487.9 504.8 2008 = 575.4 Engineering & supervision 347.9 348.5 353.7 400 J F M A M J J A S O N D Starting with the April 2007 Final numbers, several of the data series for labor and compressors have been converted to accommodate series IDs that were discontinued by the U.S. Bureau of Labor Statistics CURRENT BUSINESS INDICATORS LATEST PREVIOUS YEAR AGO CPI output index (2000 = 100) Jun. '09 = 88.7 May. '09 = 89.0 Apr. '09 = 89.6 Jun. '08 = 105.9 CPI value of output, $ billions May. '09 = 1,418.9 Apr. '09 = 1,394.1 Mar. '09 = 1,394.7 May. '08 = 2,003.0 CPI operating rate, % Jun. '09 = 65.0 May. '09 = 65.1 Apr. '09 = 65.3 Jun. '08 = 77.6 Producer prices, industrial chemicals (1982 = 100) Jun. '09 = 229.8 May. '09 = 218.8 Apr. '09 = 218.3 Jun. '08 = 295.3 Industrial Production in Manufacturing (2002=100)* Jun. '09 = 93.8 May. '09 = 94.3 Apr. '09 = 95.4 Jun. '08 = 111.0 Hourly earnings index, chemical & allied products (1992 = 100) Jun. '09 = 148.2 May. '09 = 147.1 Apr. '09 = 146.1 Jun. '08 = 140.8 Productivity index, chemicals & allied products (1992 = 100) Jun. '09 = 129.0 May. '09 = 129.4 Apr. '09 = 129.3 Jun. '08 = 131.1 CPI OUTPUT INDEX (2000 = 100) CPI OUTPUT VALUE ($ BILLIONS) CPI OPERATING RATE (%) 120 2500 85 110 2200 80 100 1900 75 90 1600 70 80 1300 65 70 1000 60 J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D *Due to discontinuance, the Index of Industrial Activity has been replaced by the Industrial Production in Manufacturing index from the U.S. Federal Reserve Board. Current business indicators provided by Global insight, Inc., Lexington, Mass. MARSHALL & SWIFT EQUIPMENT COST INDEX CURRENT TRENDS 1500 (1926 = 100) 2nd Q 1st Q 4th Q 3rd Q 2nd Q onthly declines in M & S INDEX Process industries, average 2009 1,462.9 1,534.2 2009 1,477.7 1,553.2 2008 1,487.2 1,561.2 2008 1,469.5 1,538.2 2008 1,431.7 1,491.7 1485 1470 M equipment prices soft- ened between April and Cement 1,532.5 1,551.1 1,553.4 1,522.2 1,473.5 1455 May, and preliminary es- Chemicals 1,504.8 1,523.8 1,533.7 1,511.5 1,464.8 1440 timates for the June CEPCI Clay products 1,512.9 1,526.4 1,524.4 1,495.6 1,453.5 Glass 1,420.1 1,439.8 1,448.1 1,432.4 1,385.1 indicate that there was a Paint 1,535.9 1,554.1 1,564.2 1,543.9 1,494.8 1425 slight increase between Paper 1,435.6 1,453.3 1,462.9 1,443.1 1,400.0 1410 May and June. CPI output Petroleum products 1,643.5 1,663.6 1,668.9 1,644.4 1,594.4 is also up over the previous 1395 Rubber 1,581.1 1,600.3 1,604.6 1,575.6 1,537.5 month, but the CPI operat- Related industries 1380 ing rate still hovers around Electrical power 1,394.7 1,425.0 1,454.2 1,454.4 1,412.8 the low point at 65% — an Mining, milling 1,562.9 1,573.0 1,567.5 1,546.2 1,498.9 1365 indication that many plants Refrigeration 1,789.0 1,807.3 1,818.1 1,793.1 1,741.4 1350 continue to shed built-up Steam power 1,490.8 1,509.3 1,521.9 1,499.3 1,453.2 1335 inventory. Annual Index: Visit www.che.com/pci 2001 = 1,093.9 2003 = 1,123.6 2005 = 1,244.5 2007 = 1,373.3 1320 for more on capital cost 1st 2nd 3rd 4th 2002 = 1,104.2 2004 = 1,178.5 2006 = 1,302.3 2008 = 1,449.3 Quarter trends and methodology. 56 CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2009
- 63. Circle 02 onp. 54 or go to adlinks.che.com/23017-02
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