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Membrane Power

Membrane Power






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    Membrane Power Membrane Power Document Transcript

    • September 2009 Multivariable Predictive www.che.com control Page 40 9StrategieS for water reuSe • Multivariable Predictive control CSTR Design for Reversible Reactions Focus on Valves CPI Energized by Battery Funding CPVC Piping In Chemical Environments Measuring Dust and Fines CFATS and Chemical Plant Security Page 34 Facts at Yourvol. 116 no. 9 SePteMber 2009 Fingertips: Heat Transfer •
    • Circle 01 on p. 62 or go to adlinks.che.com/23018-01
    • Circle 04 on p. 62 or go to adlinks.che.com/23018-04
    • Silverson’s high shear Batch mixers don’t just mix; theyemulsify, homogenize, solubilize, suspend, disperseand disintegrate solids. Every high shear Batch mixer inour range significantly outperforms conventional mixers bycutting processing times by up to 90% while improvingquality, product consistency and process efficiency. Silverson High Shear Batch Mixers will: • Process from 1 to 8000 gallons • Eliminate agglomerates and fish eyes • Create stable emulsions and suspensions • Reduce particle size • Rapidly dissolve solids • Accelerate reactions For more information or a free trial give us a call @ 800.204.6400 Mixing at the speed of silverson.com Circle 13 on p. 62 or go to adlinks.che.com/23018-13
    • September 2009 In ThIs Issue Volume 116, no. 9 Commentary 5 Editor’s Page Honoring in- novation The Kirkpatrick Chemi- cal Engineering www.che.com Achievement Award has honored the most noteworthy,Cover story commercialized,34 Cover Story Strategies For chemical engineer- Water Reuse Membrane ing technologies technologies increase the since 1933. This sustainability of industrial pro- year’s five finalists cesses by enabling large-scale have been selected water reuse departmentsneWs Letters . . . . . . . . . 611 Chementator A cost-effective process for recycling wastewater; A pro- Bookshelf . . . . . 8, 9 tective coating helps fine powders flow, 46 Engineering Practice CSTR Design for Reversible Reactions Here, a design ap- Who’s Who . . . . 31A without agglomeration; Process optimi- zation software allows rapid setup, cost proach for continuous stirred-tank reactors Reader Service savings; More efforts to make biofuels is outlined for three cases of second-order page . . . . . . . . . . 62 from algae ... and from microorganisms; reactions Economic New heating technique improves zeolite 50 Engineering Practice CPVC Piping in Indicators . . . 63, 64 membrane performance; Pt-free catalysts Chemical Environments: Evaluating the promise to lower fuel-cell costs ... as does Safety Record No torches, fewer burn advertisers reducing the Pt load; This process may hazards and outstanding fire characteristics produce electricity from low-temperature Product Showcase . 56 make CPVC a safe, effective alternative for geothermal resources; An activated car- industrial piping Classified bon for picking up heavy metals; Fast Advertising . . 57–60 digestion makes better use of municipal equipment & serviCes sludge; and more Advertiser Index . 61 32D-1 ISA Show Preview (Domestic16 Newsfront CPI Energized By Battery Edition) These power supplies are op- Coming in Funding The U.S. Dept. of Energy awards timized for driving inductive loads; A oCtober $1.5 billion to scale up battery production new gage with data-logging feature is Look for: Feature for electric-powered cars introduced; This oxidation-and-reduction Reports on Filtra- potential sensor is built to last; Measure21 Newsfront Chemical Plant Security tion; and Flowmeters; water and CO2 to low ppm range with While security has long been a concern for an Environmental this gas analyzer; Industrial electronics firm the CPI, impending regulatory changes (to Manager article on offers a host of new products; Customers CFATS) have everyone’s attention Preventing Dust Explo- can configure these valves using online sions; an Engineer-engineering tools; and more ing Practice article24 Solids Processing Measuring Dust and 32I-2 New Products & Services (Interna- on Compressed Gas Fines in Polymer Pellets The ability to tional Edition) Coriolis meters for low-flow Cylinder Safety; A carry out such measurements can help applications; An optimum valve for recip- Focus on Analyzers; operators improve quality control, assess rocating pumps; This thermocouple con- News articles on equipment performance and optimize the nector communicates wirelessly; A kneader Chemical Engineering process for high-fill, rigid-PVC compounding; Save Salaries; and Pressure space with a new size of mini ball valves; Measurement & Con-31B Facts At Your Fingertips Heat Transfer Monitor processes remotely with this sta- trol; Facts at Your This one-page guide outlines consider- tion; and more Fingertips on Corro- ations for designing a heat-transfer system 54 Focus Valves New radial diaphragm sion; and more40 Feature Report Multivariable Predictive valves improve “cleanability”; Achieve lower Control: The Scope is Wider Than You air leakage with these rotary valves; These Cover: Double-walled Think With tighter integration between sampling valves are designed for ease of hollow-fiber ultrafiltra- process units and more aggressive opti- use; This rotary valve is designed for com- tion membranes are mization goals, this technique is gaining plete shutoff and long life; Use this device widely used in water attention throughout the CPI as an alterna- to lock out plug valves; This valve is de- treatment tive to PID control signed for slurries and corrosives; and more The Dow Chemical Co. ChemiCal engineering www.Che.Com September 2009 3
    • Our calibration is worth its weight in gold. Promass F Coriolis mass flow measurement Tested on the world’s finest production calibration rigs, Promass F shines not only on the outside; it also shines thanks to its performance. With its robust design and unparalleled stability in operation, it greatly increases the value of your facilities. Promass F is ideal for virtually all fluids and measures several process parameters directly in the pipeline: Mass and volume flow, density, concentration as well as temperature. This means that expensive raw materials and semi-finished products are measured reliably, strict quality requirements are observed to the letter and maintenance costs are reduced significantly. • High degree of accuracy in practice: resistant to vibration, temperature and pressure changes • Optimum installation flexibility thanks to various process connections from 3/8” to 10” (DN 8 to 250) • High-temperature version up to 662°F (350°C) • National and international approvals for custody transfer • Excellent measuring accuracy: Promass F ±0.05%; calibration rig ±0.015% • Internationally accredited, fully traceable calibration rigs according to ISO/IEC 17025 (SAS, A2LA, CNAS)Endress+Hauser, Inc2350 Endress PlaceGreenwood, IN 46143 Sales: 888-ENDRESSinquiry@us.endress.com Service: 800-642-8737www.us.endress.com Fax: 317-535-8498 Circle 06 on p. 62 or go to adlinks.che.com/23018-06
    • Winner of Eight Jesse H. Neal Awards for Editorial Excellence Editor’s Page Published since 1902 Honoring innovation T An Access Intelligence Publication he first round of judging in Chemical Engineering’s 2009 KirkpatrickPublisHEr Art & dEsiGN Chemical Engineering Achievement Award competition (CE, January,MikE O’rOurkE dAvid WHitcHEr p. 19) has produced the following five finalists (in alphabetical order):Publisher Art Director/ • The Dow Chemical Co. (Midland, Mich.) and BASF SE (Ludwigshafen,morourke@che.com Editorial Production Manager dwhitcher@che.com Germany), for an industrial process for producing propylene oxide (PO)EditOrs PrOductiON via hydrogen peroxiderEbEkkAH J. MArsHAllEditor in Chief MicHAEl d. krAus • DuPont (Wilmington, Del.), for commercializing Cerenol — a new family VP of Production & Manufacturingrmarshall@che.com mkraus@accessintel.com of high-performance polyether glycols made from corn-derived 1,3-pro-dOrOtHy lOzOWskiManaging Editor stEvE OlsON panediol (Bio-PDO)dlozowski@che.com Director of Production & • Lucite International (Southampton, U.K.), for its Alpha technology — a ManufacturingGErAld ONdrEy (Frankfurt) solson@accessintel.com new process for making methyl methacrylate (MMA)Senior Editorgondrey@che.com WilliAM c. GrAHAM • Solvay S.A. (Brussels, Belgium), for its Epicerol process — a new process Ad Production ManagerkAtE tOrzEWski bgraham@che.com for producing epichlorohydrin from glycerineAssistant Editorktorzewski@che.com MArkEtiNG • Uhde GmbH (Dortmund) and Evonik Industries AG (Essen, both Ger-scOtt JENkiNs HOlly rOuNtrEE many), for the HPPO process for making PO via H2O2Associate Editor Marketing Manager hrountree@accessintel.com From these five finalists — selected by heads of chemical engineering de- desjenkins@che.com AudiENcE partments of U.S. and European universities — the winner will be chosen bycONtributiNG EditOrs dEvElOPMENt a board of judges composed of chemical-engineering-department heads thatsuzANNE A. sHEllEy sylviA siErrAsshelley@che.com Senior Vice President, were selected by their peers. In the December issue, the winner will be an-ancHArlEs butcHEr (U.K.) Corporate Audience Development nounced, along with process details for all five technologies being honored. ssierra@accessintel.comcbutcher@che.com The aim of the biennial competition (established in 1933) is to honor thePAul s. GrAd (Australia) JOHN rOckWEllpgrad@che.com Vice President, most noteworthy chemical engineering technology to have been commer- commertEtsuO sAtOH (Japan) Audience Development Chemical cialized during the previous two years, the key criteria being the novelty jrockwell@accessintel.comtsatoh@che.com lAuriE HOfMANN of the technology and the difficulty of the chemical engineering problemsJOy lEPrEE (New Jersey) Audience Marketing Director encountered and solved. As editor of this magazine’s Chementator depart- departjlepree@che.com lhofmann@Accessintel.comGErAld PArkiNsON ment, it gives me great pleasure to congratulate the chemical engineers tErry bEst(California) gparkinson@che.com Audience Development Manager and chemists involved in developing these noteworthy process technolo- technoloEditOriAl tbest@accessintel.com gies because they — the people involved — are the ones being honored.AdvisOry bOArd GEOrGE sEvEriNE It is through their efforts and innovations that keep the chemical process Fulfillment ManagerJOHN cArsON gseverine@accessintel.com industries (CPI) at the forefront of improving our standard of living, byJenike & Johanson, Inc.dAvid dickEy JEN fElliNG enhancing the performance of products that are made and by reducing the List Sales, Statlistics (203) 778-8700MixTech, Inc. j.felling@statlistics.com environmental impact of the methods used to make them.MukEsH dOblE cONfErENcEs Each of the five process technologies being honored involve alternativeIIT Madras, IndiaHENry kistEr dANA d. cArEy routes with “greener” feedstocks, when compared with the conventional Director, Global Event SponsorshipsFluor Corp. dcarey@chemweek.com routes used to making the products. They all tout lower energy consump- consumptrEvOr klEtz tion, reduced side products and, thus, lower production costs. And whileLoughborough University, U.K. PEck siMGErHArd krEysA Senior Manager, their employers will be happiest about the “bottom-line” advantages, we Conference ProgrammingDECHEMA e.V. psim@chemweek.com residents of planet Earth can take some comfort that efforts to cut costsrAM rAMAcHANdrAN bEAtriz suArEz also reduce the impact to our climate, the air we breath, the water we drinkBOC Director of Conference Operations bsuarez@chemweek.com and the land in which we grow our food.iNfOrMAtiON sErvicEsrObErt PAciOrEk cOrPOrAtE While the five finalists now join a distinguished list of former Kirkpat-Senior VP & Chief Information Officer stEvE bArbEr rick honorees, they, and the nominees not making the final round, alreadyrpaciorek@accessintel.com VP, Financial Planning & Internal Audit sbarber@accessintel.com belong to an ever-growing list of companies and the engineers and chem- chemcHArlEs sANdsSenior Developer briAN NEssEN ists they employ to continuously improve the process technologies used toWeb/business Applications Architect Group Publisher make products.csands@accessintel.com bnessen@accessintel.com CE takes pride in honoring these achievements every two years with theHEAdquArtErs Kirkpatrick Chemical Engineering Achievement Award, every two alter- alter110 William Street, 11th Floor, New York, NY 10038, U.S.Tel: 212-621-4900 Fax: 212-621-4694 nate years with the Personal Achievement Award, andEurOPEAN EditOriAl OfficEs every month in the Chementator department. ReadersZeilweg 44, D-60439 Frankfurt am Main, Germany of CE regularly look to those pages to keep abreast ofTel: 49-69-2547-2073 Fax: 49-69-5700-2484 the latest process technology and equipment innova-innovacirculAtiON rEquEsts:Tel: 847-564-9290 Fax: 847-564-9453 tions that have been discovered, scaled up or commer- commerFullfillment Manager; P.O. Box 3588, cialized for the first time. If you are working on such aNorthbrook, IL 60065-3588 email: clientservices@che.com process and believe you and your employer deserve toAdvErtisiNG rEquEsts: see p. 62 be recognized, too, please let us know; we’d love to hearFor photocopy or reuse requests: 800-772-3350 or info@copyright.comFor reprints: chemicalengineering@theygsgroup.com from you. n Gerald Ondrey ChemiCal engineering www.Che.Com September 2009 5
    • Raymond® & Bartlett-Snow™ Thermal Equipment & Systems Letters Raymond and Bartlett-Snow ® ™ products have been success- fully providing solutions for Honoring the man thermal process applications behind the scenes involving chemical, petro- The readers of Chemical En- chemical, ceramic, magnetic, gineering rarely get an inside metals, food, fertilizer, plastic, look at how this publication industrial solid waste and is put together. Since it would nuclear industries. For over a easily have gone undetected, century, we have provided we wish to recognize a long- innovative and dependable standing tradition that is equipment and systems for coming to a close. The October the changing needs of these industries worldwide. issue will mark the first issue in 50 years that does not involve Bill Graham, the person Rotary Calciners who handles our print production. Rotary Dryers Our readers do not know him, but most of our advertis- ers have communicated with him in one way or another Rotary Coolers since Aug. 24, 1959 (photo). For our readers, he has put Rotary Kilns together an award winning publication every month and never asked to be recognized. For our salespeople, he has Flash Dryers worked endless times to squeeze in a last minute ad or to try to get a better position for one of their clients. For the 4525 Weaver Pkwy, Warrenville, IL 60555 editors, he is the one who puts together the puzzle and Toll free: 877.661.5509 makes everything fit each month. Tel: 630.393.1000 • Fax: 630.393.1001 Air Preheater Company Raymond Operations Email: info@airpreheatercompany.com Over the last 50 years, a lot of things have changed in the publishing industry. When Bill started, we had prepress TM www.bartlettsnow.com rooms, typesetting and negatives for all of the advertise- Circle 07 on p. 62 or go to adlinks.che.com/23018-07 ments. These days everything is done digitally. Bill has mastered the production work regardless of how it was done. Bill has been many things to me since I joined Chemical Engineering. He has been my historian, mentor and co- worker, but mostly he has been my friend, and I am going to miss him. Thank you, Bill, for your 50 years of service! Mike O’Rourke, Publisher Chemical Engineering True loyalty deserves recognition Over one’s career, colleagues frequently come and go — sometimes without much pomp or circumstance mark- ing their departures. In fact, an employee with five or more years working with a single company has come to be thought of as relatively loyal by today’s standards. A higher exhibit of loyalty, however, is why we take pause to honor our colleague Bill Graham, who, with this issue, HIGH ACCURACY FLOW METERS celebrates 50 years with Chemical Engineering. FOR HIGH TEMPERATURES Bill has devoted his entire career to this publication and holds it in the highest esteem. He never seeks recogni- AND HIGH PRESSURES tion and yet has been a key contributor to its success. The magazine would never be what it is today without his flex- – non-intrusive ultrasonic clamp-on technology ibility, advice, hard work and, above all else, respect for – for temperatures up to 750 °F – independent of process pressure the reader. – multi-beam for high accuracy www.flexim.com As our previous Editor-in-Chief once reassured me upon usinfo@flexim.com – wide turn down the departure of another colleague, there has never been, – installation without process shut down FLEXIM Instruments LLC and never will be, a single individual whose exit would – no maintenance CA: (510) 420-6995 cause this magazine to cease publication. But Bill’s depar- – no pressure loss NY: (631) 492-2300 – standard volume calculation TX: (281) 635-2423 ture does mark the end of an era here. It will be another 32 years, at the very least, before we can celebrate an em- TYPICAL APPLICATIONS: ployee’s 50 year anniversary. Thank you for your loyalty, HEAT TRANSFER OILS | BITUMEN | PITCH/TAR | COKER FEED | CRUDE OILS/SYNTHETIC Bill. We will miss you. CRUDE | GAS OILS | REFINED PETROLEUM PRODUCTS | HOT OR TOXIC CHEMICALS Rebekkah Marshall, Editor in Chief Chemical Engineering Circle 08 on p. 62 or go to adlinks.che.com/23018-08 6 ChemiCal engineering www.Che.Com September 200987_Flexim-Anzeige-ChemEngin 1 11.01.2008 11:18:49 Uh
    • Do you see a dragon? We also see a challenge to reduce carbon footprints by using energy more efficiently. Veolia Energy develops and implements sustainable solutions such as cogeneration (capturing and converting heat into energy), renewable energy resources and optimized efficiency of customers’ on-site infrastructure and complex equipment. In 2008, the energy efficiency we created provided carbon emission reductions in excess of 6.2 million tons of carbon dioxide. The environment is our universal challenge.Learn more about the high-quality energy and facility operations and management veolianorthamerica.comservices we have implemented for the Galleria Shopping Center in Houston. Circle 09 on p. 62 or go to adlinks.che.com/23018-09
    • BookshelfGuidelines for Chemical Transportation Safety, Security, and Chapter one introduces trans-Risk Management, 2nd Edition. By the Center for Chemical portation risk management, asProcess Safety/AIChE. John Wiley & Sons, Inc. 111 River well as key stakeholders in theSt., Hoboken, NJ 07030. Web: wiley.com. 2008. 166 pages. supply chain and risk management$125.00 process. Chapter two discusses baseline programs for safety andReviewed by: Stanley S. Grossel, security management for all modes of hazardous materialProcess Safety & Design Consultant, Clifton, N.J. transport that need to be in place prior to a risk analysis. Risk assessment fundamentals are discussed in Chap-H azardous chemical transport poses significant pub- ter three, as is a protocol for conducting transportation lic health and environmental risks. In 1995, the risk assessments. Chapter four focuses on qualitative and CCPS published “Guidelines for Chemical Trans- semi-qualitative techniques that can be used to analyzeportation Risk Analysis.” The book reviews risk analysis the safe transport of hazardous materials. Chapter fivetechniques used to evaluate chemical transportation oper- provides an overview of quantitative risk analysis (QRA)ations. The new edition serves as a complement to, rather techniques for evaluating hazardous materials transpor-than a replacement for, the 1995 edition, and the earlier tation issues, including data sources and requirements,guidelines are included in CD form along with four other analysis techniques, and the generation and interpreta-appendices. The new publication addresses transporta- tion of quantitative risk results.tion security and risk management broadly and provides Chapter six presents current security guidelines andtools and methods for a wider range of transportation regulations, and a methodology for adapting and apply-professionals and stakeholders. In particular, it introduces ing security vulnerability assessment (SVA) techniquesqualitative and practical techniques for identifying and designed for fixed chemical facilities to account for themanaging higher-level risk issues that balance safety and differences specific to transportation. Risk reductionsecurity. Together, the two books can help effectively ana- strategies are discussed in Chapter seven, which provideslyze and manage chemical transportation risk. guidance on developing risk reduction strategies and From formulation to wastewater treatment, Myron L Water Quality Instruments provide accurate reliable measurements of key parameters: CONDUCTIVITY, RESISTIVITY, TDS, ORP, PH & TEMPERATURE Monitor/ Ultrameter II 6P™ TechPro II TPH1™ controllers pDS Meter ™ See our full line of quality instruments at www.myronl.com MADE IN USA 2450 Impala Drive Carlsbad, CA 92010 Tel: 760-438-2021 Fax: 760-931-9189 Circle 10 on p. 62 or go to adlinks.che.com/23018-108 ChemiCal engineering www.Che.Com september 2009
    • highlights the factors that influence the different typesof safety and security measures that can be selected andultimately implemented. The book concludes with tips forkeeping risk management practices current with chang-ing trends and regulations. It is an excellent informationsource for those involved with chemical transport safety. Petroleum Microbiology, Concepts, Environmental Implications, In- dustrial Applications, vols. 1 and 2. By Jean-Paul Vandecasteele. Editions Technip, 25 rue Ginoux, 75015 Paris, France. Web: editionstechnip.com. 2008. 816 pages. $200.00 Scaling Analysis in Modeling Transport and Reaction Processes: A Systematic Approach to Model Building and the Art of Approxima- tion. By William Krantz. John Wiley and Sons, 111 River Road, Hoboken, NJ 07030. Web: wiley.com. 2007. 529 pages. $115.00. Polymer Melt Processing: Founda- tions in Fluid Mechanics and Heat Circle 11 on p. 62 or go to adlinks.che.com/23018-11 Transfer. By Morton Denn. Cambridge Univ. Press, 32 Avenue of the Americas, New York, NY 10013-2473. Web: cam- bridge.org. 2008. 250 pages. $99.00. Reactive Distillation Design and Control. By William Luyben and Cheng-Ching Yu. John Wiley and Sons, 111 River Road, Hoboken, NJ 07030. Web: wiley.com. 2008. 574 pages. $130.00. Diffusion: Mass Transfer in Fluid Systems, 3rd Ed. by E.L. Cussler. Cambridge University Press, 32 Av- enue of the Americas, New York, NY 10013-2473. Web: cambridge.org. 2009. 631 pages. $80.00. Nanotechnology: Basic Calcula- tions for Engineers and Scientists. By Louis Theodore. John Wiley and Sons, 111 River Road, Hoboken, NJ 07030. Web: wiley.com. 2006. 459 pages. $105.00. Nano and Microsensors for Chemi- cal and Biological Terrorism Sur- veillance. Edited by Jeffrey Tok. RSC Publishing, Milton Road, Cambridge, CB4 0WF, UK. Web: rsc.org. 208 pages. $148.00. ■ Scott Jenkins Circle 12 on p. 62 or go to adlinks.che.com/23018-12 ChemiCal engineering www.Che.Com september 2009 9
    • Circle 20 on p. 62 or go to adlinks.che.com/23018-20
    • Edited by Gerald Ondrey September 2009 Untreated Process Oxygen and air injection water control controlled by DO and pH feedback loops OxygenA cost-effective process Return flow used for oxygenationfor recycling wastewater and process mixing AirA wastewater treatment process that con- Bioreactor sumes less energy, produces less sludge Membrane DO = dissolved O2and makes available up to 75% of the water modules RO = reverse osmosisfor reuse — including that of potable water Separation of biomassquality — has been commercialized by /treated water TreatedLinde Gases, a division of The Linde Group RO process water Water reuse/(Munich, Germany; www.linde.com). The so- Bio-treatment and water reuse final disposal and oxygenationcalled Axenis process is suitable for treatingwastewater with soluble organic pollutants, The return flow from the UF membranessuch as that generated by biodiesel produc- is used for injecting O2 and air, and to Making a C–F bondtion and the food, dairy, paper-and-pulp, pig- achieve mixing in the MBR, thereby elimi- Pharmaceuticals and agro-ments and cellulose (starches) industries, nating the need for an additional aeration chemicals often incorporatesays Darren Gurney, process engineer at device and agitator, says Gurney. This con- a fluorine atom within theirLinde Gases. Axenis handles wastewater figuration also has the effect of recovering molecular structure to improvewith COD (chemical oxygen demand) lev- some of the energy needed for separation, he properties, such as keeping theels in the range of 2,000 to 100,000 mg/L, says. The controlled use of O2 (for biological body from metabolizing a drughe says. treatment) and air (to control pH) enables too rapidly. However, adding a Axenis utilizes the patented, oxygen-based the MBR to operate at about 5–10°C higher fluorine to an aromatic ring at aVairox technology in a membrane bioreactor than conventional MBRs without the associ- late stage of the synthesis can be difficult and expensive due(MBR) in combination with cross-flow ultra- ated production of surplus biological sludge. to the harsh conditions neededfiltration (UF) and reverse osmosis (RO) in Operating at this higher temperature can by traditional methods. Now,an integrated, automated unit. In the pro- lead to a 10% or more increase in flux rate. chemists at the Massachusettscess (flowsheet), wastewater is first fed to an As a result, the reactor can be at least one- Institute of Technology (MIT;MBR, where bacteria oxidize the COD into half, and in some cases, as much as one-third Cambridge; www.mit.edu) haveCO2 and water. The waste stream is then the size of conventional MBRs for the same devised a new way to add a flu-pumped through a tubular UF (cutoff range capacity, says Gurney. orine atom to an aromatic com-of 0.001 to 0.03 microns) membrane module The first commercial reference of Axenis pound with a single catalyticto remove suspended solids. Finally, RO is — a retrofit at a U.K. company treating 2 step. In the reaction, a palladiumused to remove dissolved inorganic com- m.t./d (metric tons per day) of COD — is now catalyst is used to exchange a triflate group (CF3SO3–) with apounds. Final water quality with BOD (bio- being built, and Gurney anticipates the first fluoride ion, which is taken fromlogical oxygen demand) and suspended sol- greenfield application to be announced in 6 a salt such as CeF.ids levels of less than 5 mg/L are achieved. mo., with startup in 2010.A protective coating helps fine powders flow, without agglomerationA team from Monash Institute of Phar- maceutical Science at Monash Uni-versity (Melbourne, Australia; www. Corp. (Osaka, Japan; www.hosokawami- cron.co.jp/en) — that has a specially de- signed fast blade, providing a fast mov- croscopy revealed significant differences in morphology: untreated and mixed batches were mostly agglomerated or hadpharm.monash.edu.au), has developed ing compressive surface. The process the particles with smooth surfaces and sharpan approach — a hybrid mixing and team has developed involves coating the edges, whereas the Mechanofusion-pro-milling process — for producing fine particles with a nano-layer of an addi- cessed samples were de-agglomerated,(1–20 µm) pharmaceutical powders with tive, which is polished into the particles’ and had rounded edges due to the attri-good flow and de-agglomeration prop- surface. The coating is believed to im- tion and deformation during the high-erties. Team leader David Morton says prove flow properties by reducing inter- shear dry-coating process. Changes insimilar methods have been applied for particle forces. surface textures indicated that the addi-bulk pigments and ceramics, but are not Fine-milled lactose samples were used tive had effectively coated the particles.generally known for such fine and cohe- as model cohesive pharmaceutical pow- The dry-coating process leads to asive powders that tend to form clumps ders, and about 1–2 wt.% magnesium substantial improvement in flow prop-that stick stubbornly together. stearate served as the additive. For com- erties for these fine lactose powders. The team used a very high shear sys- parison, the samples were processed in Changes in powder-packing structuretem — a Nobilta “Mechanofusion” pro- a conventional mixer and the Mechano- are thought to be responsible for an ob-cessor developed by Hosokawa Micron fusion processor. Scanning electron mi- served doubling of the pour density.Note: For more information, circle the 3-digit numberon p. 62, or use the website designation. CHeMICal eNgINeerINg www.CHe.COM SePTeMber 2009 11
    • C hementato R More efficient smeltingProcess optimization software the energy efficiency at two record-breaking aluminumallows rapid setup, cost savings smelters in the middle east has been increased by 18%, thanksN ew industrial process-optimization soft- ware can be fully operational in sevendays — months ahead of existing predic- recipe requirements that need constant correction, the software reduces out-of- specification product and improves process to abb’s (Zurich, switzerland; www.abb.com) new rectiform- ers — the high-power compo-tive monitoring systems, according to Slip- efficiency. Companies can realize a 1–5% in- nents that control and convertstream Software (Alpharetta, Ga.; www.slip- crease in efficiency, which, in a typical chem- alternating current from the grid to direct current needed tostreamrpm.com). The company’s proprietary ical plant, could mean a few million dollars power the electrolytic processdata-modeling tools are responsible for the of savings annually, explains company CEO and produce molten al in pots.reduced setup time. By mining process his- Gary Hopkins. In addition, predictive pro- the rectiformers were devel-tory information, and collecting data from cess systems can take four to six months oped for the sohar al smeltersensors installed in the process stream, of engineering time to set up, and can cost in sultanate of oman, whichSlipstream software “dynamically reads, close to $1 million. Slipstream software can consists of 360 pots and pro-models and auto-corrects customer recipes,” achieve the same functionality in a week for duces up to 360,000 ton/yr ofthe company says. around one-fifth of the price, he adds. al — the world’s largest potline The process optimization software can be According to Slipstream, a Belgian food- (startup June 2008) — andused in wet processes (using infrared spec- additive manufacturer using its software the Qatalum smelter in Qatar, which will become the world’stroscopy as the basis for the sensors) or dry saw a 4% efficiency jump, and a paper-pulp largest aluminum smelter when(using characteristic sound vibrations) and maker saw its profits jump by 20% after in- it starts up in late 2009, with ais designed to interface with a plant’s dis- stalling the pattern modeling software. production capacity of 585,000tributed control (DCS) or supervisory con- The new software represents an addition ton/yr and 704 pots.trol and data acquisition (SCADA) system. to the company’s portfolio of root cause ana- For these massive projects, Designed for industrial processes with lytics products. abb was able to extend the voltage limit of the rectiform- ers from 1,200 V d.c. to 1,650More efforts to make biofuels from algae . . . V d.c. (for sohar) and 2,000 V d.c. for Qatalum. this enablesO ver the past few weeks there has been a number of announcements on proj-ects aimed to further develop algae-to-fu- Meanwhile, petroleum major ExxonMo- bil (Irvine, Tex.; www.exxonmobil.com) has formed an alliance with Synthetic Genomics the devices to convert and deliver more power than previ- ously possible. as a result,els technology (see also, “Pond Strength,” Inc. (SGI; La Jolla, Calif.; www.syntheticge- each smelter requires only fiveCE, September 2008, pp. 22–25). Plankton nomics.com) to develop next generation bio- rectiformers instead of the sixPower (Wellfleet; www.planktonpower.com) fuels from algae, following earlier leads by needed at the lower voltage,and the Regional Technology Development Shell (CE, January 2008, p. 15), Akzo-Nobel resulting in a “huge” savings inCorp. of Cape Cod (RTDC; Woods Hole, both (CE, July 2008, p. 16) and ConocoPhillips investment, says abb.Mass.; www.regionaltechcorp.org) have (www.che.com, July 2, 2008).formed a consortium to establish the Cape In July, The Dow Chemical Co. (Midland, Ag/polymer reflectorCod Algae Biorefinery, which will focus on Mich.; www.dow.com) said it would work scientists at skyFuel inc.pilot- and commercial-scale development of with Algenol Biofuels, Inc. (Bonita Springs, (arvada, Colo.; www.skyfuel.algae-based biodiesel. The proposed biore- Fla.; www.algenolbiofuels.com) to build and com) and the national re-finery will be located on 5 acres of land operate a pilot-scale, algae-based integrated newable energy laboratoryat the Massachusetts Military Reserva- biorefinery to make ethanol. (golden, Colo.; www.nrel.gov)tion (Bourne). Starting in the fall of 2010, In Germany, scientists at the Karlsruhe have developed a silveredPlankton Power expects to produce 1-mil- Institute of Technology (Germany; www. polymer film as a less expen- sive alternative to glass mirrorlion gal/yr of biodiesel in pilot-scale opera- kit.edu) are developing a closed, vertically reflectors. Curved sheets oftions, using the company’s cold-saltwater arranged photobioreactor that is said to the reflective material are usedalgae species. Commercial-scale operations be five-times more efficient at converting in solar troughs, which reflecton 100 acres could produce 100-million gal/ solar energy into biomass than open ponds. concentrated solar radiation onyr, which would meet 5% of the demand for A pulsed electric treatment process is also a tube filled with a heat transferdiesel and home heating fuel in the state of being developed at KIT for extracting oils fluid. Developers claim the costMassachusetts, says the firm. and other chemicals from biomass. advantage of the multi-layered polymer material is 30% when compared to glass mirrors,. . . and from microorganisms which are more expensive, heavier and more difficult toL ast month, BP Corp. (London; www.bp.com) signed a joint-development agreement withMartek Biosciences Corp. (Columbia, Md.; cept for large-scale, cost-effective production of microbial biodiesel. The concept is to utilize microorganisms to ferment sugars into lipids, install for collecting solar radia- tion. a pilot system including the polymer-silver reflectors iswww.martek.com) to work on the production which will then be processed into liquid fuels. operational at skyFuel’s facilityof microbial oils for biofuels applications. The BP is contributing $10 million to the initial in arvada, Colo.two companies aim to establish proof of con- phase of the collaboration. 12 ChemiCal engineering www.Che.Com september 2009
    • New MAK & BAT values the senate Commission for the investigation of health haz- ards of Chemical Compounds in the work area, establishedNew heating technique improves by the german researchzeolite membrane performance Foundation (DFg; bonn) has issued the maK (maximumA dding a rapid heat-treatment step to the Grain boundary defects form during calcina- concentration at the workplace) process of making zeolite membranes tion, a heating process required to remove and bat (biological tolerance)improves separation performance by elimi- structure-directing agents (SDAs) from zeo- Values list for 2009, which contains 62 changes and newnating grain boundary defects, according to lite pores. SDAs are added during synthesis entries. these include revisedresearchers from the University of Minne- to define zeolite pore size and shape. assessments of oxides of nitro-sota (UMN; Minneapolis, Minn.; www.umn. The research group developed a rapid ther- gen, and zinc and its inorganicedu), who published their study in the July mal processing (RTP) technique that may compounds.31 issue of Science. strengthen bonding between adjacent zeolite although the trace element The study could inform efforts aimed at crystal grains prior to removal of the SDAs. zinc, which is ingested throughproducing zeolite films for gas, liquid and In RTP, an infrared-lamp-based furnace is food, is a component of impor-vapor membrane separations processes, as used to heat synthesized zeolite membranes tant enzymes, it can have toxicwell as for hybrid membrane-distillation to 700°C within one minute prior to removal effects on the lungs if inhaled.processes that separate industrial mixtures. of the SDAs. The elevated temperature is therefore, the maximum con- centration of zinc oxide fumesIf zeolite membranes could be fabricated to maintained for 30 s to 2 min before the mem- in the breathing air to whichdeliver expected performance in flux and se- brane is cooled by water circulation. workers can be exposed withoutlectivity, they could reduce the energy costs Tsapatsis hypothesizes that the increased suffering adverse health effectsassociated with distillation by 10-fold, notes crystal-to-crystal bonding — which may re- is considerably lower than wasprofessor Michael Tsapatsis, a UMN chemi- sult from condensation reactions of Si-OH previously stated, says the DFg.cal engineer who led the research. groups on neighboring crystals — reduces the there are also seven revisions Large-scale production of zeolite films has development of cracks and grain boundary or alterations in the carcino-been plagued by the formation of cracks and defects in the membrane. When SDAs were genic substances category,grain boundary defects. Membrane defects removed in a subsequent heating step, the including the categorization ofdegrade selectivity by allowing molecules to researchers observed an increased selectiv- the chromates (except lead and barium chromate) as carcino-bypass the zeolite pores that are designed ity when the RTP-treated zeolite films were genic to humans. the completeto discriminate among mixture components. used to separate o-xylene from p-xylene. list can be downloaded at www. dfg.de.Pt-free catalysts promise to lower fuel-cell costs . . . Dust explosion advice the U.s. occupational safetyS howa Denko K.K. (Tokyo; www.sdk.co.jp/ html/english) has developed a platinum-substitute catalyst system for polymer elec- efficiency, in terms of open-circuit voltage and durability, among non-Pt catalysts an- nounced so far. Enhanced durability has also and health admin. (osha; washington, D.C.; www.osha. gov) has recently publishedtrolyte fuel cells (PEFCs) under the New been observed, with operation extending to a new guidance documentEnergy and Industrial Technology Devel- more than 10,000 h, says the firm. — hazard Communicationopment Organization’s (NEDO; Kawasaki, Production costs for the new catalysts are guidance for CombustibleJapan) project led by professor Kenichiro about ¥500/kW ($5/kW), or less, which is Dusts — that helps chemicalOta of Yokohama National University. The about 1/20th that of today’s Pt-based cata- manufacturers and importersnew catalysts — based on niobium oxide lysts. The company is working to improve to recognize the potentialand titanium oxide, each containing nitro- the catalyst performance using fine-particle for dust explosions, identify appropriate protective measuresgen and carbon atoms — are used in both manufacturing technologies and high-con- and the requirements forthe cathode and anode of a PEFC and are ductivity carbon, and anticipates commer- disseminating this informationsaid to achieve the world’s highest level of cial production by 2015. on material safety data sheets and labels. the document can be downloaded from osha’s. . . as does reducing the Pt load website for free.A technique for making PEFC elec- trodes with one fourth the amountof platinum catalyst compared to con- materials with a high performance level when used in the membrane-electrode assembly (MEA) of PEFCs. Naitou fabri- generation characteristics as conven- tional systems even when reducing the Pt content by 75%. The enhanced cata-ventional PEFCs has been developed by cated the composite catalyst, composed lyst activity is thought to be the result ofHosokawa Micron Corp. (Osaka, Japan; of commercially available platinum-car- increasing the electrochemically activewww.hosokawamicron.co.jp/en) in col- bon particles and tungsten-carbide par- surface created by MCB technology. Thelaboration with professors Kiyoshi Ka- ticles. Kanamura fabricated the MEA by researchers believe the Pt load can benamura, Tokyo Metropolitan University, incorporating a Nafion membrane, and reduced by 90% through optimizing theand Makio Naitou, Osaka University. evaluated the MEA’s power-generation fine structure of the particles. HosokawaThe method, known as mechanochemical characteristics. Micron is continuing to improve its AMS-bonding (MCB), produces stable, complex The scientists obtained similar power- Mini device for MCB applications. ChemiCal engineering www.Che.Com september 2009 13
    • C hementato RThis process may produce electricityfrom low-temperature geothermal resourcesT he world has vast geothermal re- sources in the temperature rangeof 150–250°F, but these temperatures ratory fellow Peter McGrail. “We have synthesized a number of MOHCs,” he says, “and the best ones we have discov- as particles of less than 100 nm and ad- sorbs as much as 30 wt.% of the fluid, so that the working density of the alkaneare too low for economical exploitation, ered so far have a latent heat of adsorp- is not reduced. He adds that the MOHCsusing today’s technology. A process tion that is 20 times the standard heat are inexpensive and the main questionthat could change the benchmark is of vaporization of the working fluid.” is whether the nanoparticles will with-being developed at Pacific Northwest McGrail declines to give details on stand longterm cycling. PNNL plans toNational Laboratory (PNNL, Richland, the composition of the MOHCs, but says answer that question with a bench-scale,Wash.; www.pnl.gov). the material is dispersed in the alkane electricity-generating prototype unit. PNNL’s process would pump hot waterfrom a geothermal reservoir and extractheat into a working fluid through a heatexchanger, a conventional process. The An activated carbon for picking up heavy metalsnew twist is that PNNL uses a bipha-sic working fluid. It consists of a metal-organic heat carrier (MOHC) suspended T he Agricultural Research Service (ARS, Beltsville, Md.; www.ars.usda. gov) has received a patent on a process tons/yr of litter, according to the ARS. The process was developed and has been laboratory-tested at the ARSin, for example, butane, pentane or pro- for producing activated carbon from Southern Regional Research Centerpane, which drives a turbine via a Rank- poultry litter, which consists of bedding (New Orleans, La.). Litter is groundine cycle. The biphasic fluid’s properties materials such as sawdust and peanut into a fine powder, pelletized, then py-promise to boost the power-generation shells, along with droppings and feath- rolyzed at 1,300–1,500°F in a nitrogencapacity of the turbine to near that of a ers. U.S.-grown broiler chickens and tur- atmosphere. Unlike conventional acti-conventional steam turbine, says Labo- keys produce an estimated 15-million vated carbon, produced from coal, the Lower operating costs with variable pitch rotary screw vacuum pumps COBRA variable pitch dry screw pumps help optimize vacuum efficiency and reduce operating costs by combining high flow rates with low power consumption and reduced utilities. Contact us today for a free cost analysis for your process application. Visit us at the Chem Show November 17-19 New York, NY Booth #210 Circle 14 on p. 62 or go to adlinks.che.com/23018-14 14 ChemiCal engineering www.Che.Com september 2009
    • Fast digestion makes better use of municipal sludgeT he use of residual sludge from munici- pal sewage plants as fertilizer in ag-riculture is controversial (due to heavy vest in the technology that is now state- of-the art in larger plants, according to a cost-benefit analysis performed by the tems. About 60% of the organic matter is converted into biogas. Using the biogas to make electricity to run the plant, andmetals and other pollutants), and slurry Fraunhofer Institute for Interfacial En- the reduced volume of sludge needed tocan no longer be disposed of in landfills gineering and Biotechnology (IGB; Stut- be disposed of, can save the operator of ain many countries. A less expensive al- tgart, Germany; www.igb.fraunhofer.de). small (28,000 inhabitants) sewage plantternative to incineration — high-rate di- In the fast-digestion process developed about €170,000/yr, according to IGB.gestion of sludge into biogas — can lead at IGB, sludge only needs to remain into substantial savings (even for small the tower for 5–7 d instead of 30–50 d Waste-heat recoverysewage plants) despite the need to in- as typical for conventional digestion sys- GE Energy (Atlanta, Ga.; www.ge.com/ energy) and ECOS Ltd. (Slovenia) plan to demonstrate a new waste-heat re- covery system that is expected to boostARS material has a relatively high con- roughly $1/kg for coal-derived carbon. the electrical efficiency of a 7.2-MWcentration of phosphorous, which adds However, she points out that conven- biogas power plant by five percentagea negative charge. This enables the car- tional activated carbon is commonly points. GE’s pilot ORC (organic Rankinbon to adsorb heavy metal ions, such as used to adsorb organics. The adsorption cycle) waste-heat recovery system willthose of cadmium, copper, lead and zinc, of metal ions would require post-treated allow ECOS to capture more wastesays Isabel Lima, a research chemist at carbon or ionic resins, both of which heat created by its Bioplinarne Lendavathe center. are much more expensive. Lima says biogas plant, in eastern Slovenia. The extra thermal power will be used to pro- Lima estimates that the process could the technology is open for licensing by duce steam, which in turn will generateproduce activated carbon for about companies interested in building small more electricity. ❏$1.44/kg, or 65¢/lb. This compares with plants in poultry-producing areas. ■ Circle 15 on p. 62 or go to adlinks.che.com/23018-15
    • Li slab Transition metal slab NewsfrontCPI ENErgIzEd bybattEry FUNdINg DOE Awards $1.5 billion to scale up battery production for electric-powered carsE fforts toward large-scale produc- technologies for road vehicles. tion of lithium-ion (Li-ion)-based In an Aug. 5 speech to announce the car batteries got a big boost in funding, U.S. Energy Secretary Ste- Transition Li site metal site Oxygen site early August, when the Obama ven Chu stated that the grants wereAdministration announced $2.4 billion handed out “not simply to boost a few Figure 1. The structure of layered metalin U.S. government investment aimed, companies, but to start an entire ad- oxides is similar among several types of cathode materials used in Li-ion batteriesin part, at dramatically ramping up vanced battery industry in America.” that are designed specifically for hybridthe supply chain for advanced batter- The $2.4 billion in grants represents electric and plug-in electric vehiclesies for the auto industry. A majority of the single biggest government invest-this funding is funneling directly into ment in electric vehicles ever. “It’s a phate material, the crystal structurethe chemical process industries (CPI), big deal,” says Jennifer Watts, com- of which contains intercalated lithiumwhich are responsible for developing munications manager at the Electric ions (Figure 1). The dominant cathodeand commercializing the necessary Drive Transportation Assn. (Washing- material in batteries for portable elec-technology. But CPI companies in- ton, D.C.; www.electricdrive.org). Es- tronic devices has been lithium cobaltvolved in this area will be challenged tablishing a domestic manufacturing oxide (LiCoO2), a material that is tooto produce batteries that meet the per- base for advanced batteries is critical costly and that carries too many safetyformance needs of the auto industry at to the future of the auto industry, and concerns to be used in HEV/PHEV bat-affordable cost. the grant funding shows that govern- teries. The DOE grant awards (Table Part of the recent economic stimulus ment and industry “are on the same 1) support large-scale production ofpackage (American Recovery and Re- page,” she commented. batteries containing several cathodeinvestment Act), the U.S. Dept. of En- Meanwhile, it gives a shot in the arm types, each exhibiting a unique struc-ergy’s (DOE; Washington, D.C.; www. to an already expanding market for ture and different metal contents.energy.gov) Electric Drive and Vehicle battery technologies. Mid-August esti- One approach to synthesizing cath-Battery and Component Manufactur- mates from the market research firm odes that can handle automobile en-ing Initiative awarded the $2.4 billion Innovative Research and Products Inc. vironments involves a metal oxidein grants to 48 different battery-tech- (iRAP; Stamford, Conn.; www.innore- structure that includes manganese andnology and electric-vehicle projects in search.net) place the global market for nickel along with cobalt. Known as an20 states. Of the $2.4 billion total, $1.5 large-format Li-ion batteries for trans- NMC cathode, the material forms thebillion in grants went to manufactur- portation at $77 million in 2009. HEVs basis of a proprietary battery technol-ers of batteries or their components, and PHEVs currently represent a neg- ogy called superior lithium polymerwhile the remaining $900 million went ligible portion of that total. The global battery (SLPB). SLPBs may be attrac-to makers of electric drive components market for Li-ion batteries in transpor- tive to automakers because the technol-and vehicles themselves. Each DOE- tation is projected to reach $332 mil- ogy has already been commercializedgrant dollar will be matched by invest- lion by 2014, with electric automobiles for specialized military and industrialments from the awardees. accounting for $87 million. Heavy-duty applications. Dow Kokam, a joint ven- The auto industry is poised to roll out hybrid electric vehicles (buses, train ture of the Dow Chemical Co. (Mid-new hybrid electric and plug-in hybrid engines, trucks) will garner the largest land, Mich.; www.dow.com) and Kokamelectric vehicles (HEVs and PHEVs) in portion of the market, at $150 million America (Lee’s Summit, Mo.; www.the next several years, and are depend- by 2014, iRAP projects. kokamamerica.com), was awarded $161ing on a ready supply of automotive- million in DOE funds to produce SLPBsgrade Li-ion batteries. But the lack Varying cathode approaches for the HEV/PHEV markets.of manufacturing capacity has been Among the crucial factors affecting The NMC cathodes employed in thea bottleneck, especially for U.S. auto- battery performance, safety and cost, is SLPB batteries exhibit low imped-makers. The competitively awarded the cathode active material. Cathodes ance, good safety characteristics andDOE grants accelerate progress toward for Li-ion batteries generally consist rapid charge and discharge, says Raviscaling-up production of viable battery of layered metal oxide or metal phos- Shanker, corporate director of Ven-16 ChemiCal engineering www.Che.Com September 2009
    • A solution in every drop of water. In the simple bond of hydrogen and oxygen, the complexity of human need presents itself. But if we apply chemistry, using the Human Element as our filter, we discover solutions as vital as water itself. Solutions like advanced desalination and re-use technology from Dow Water Solutions that make the purification and recycling of municipal water possible. Dow Water Solutions’ reverse osmosis technology is at work in three wastewater reclamation and reuse facilities in Beijing, China. Reverse osmosis technology enables Beijing to meet its 50 percentwww.dow.com/hu wastewater reuse rate for the 2008 Beijing Olympic®™The DOW Diamond Logo and Human Games this summer. It also helps address growingElement and design are trademarks ofThe Dow Chemical Company © 2008 worldwide demand for water and China’s own commitment to conservation and reuse. Caring for man is caring for the future of mankind. And that is what The Dow Chemical Company is all about. www.dowwatersolutions.com Circle 16 on p. 62 or go to adlinks.che.com/23018-16
    • Company name Award Technology Editors notes (project locations) amount (in millions of U.S. dollars) Johnson Controls 299.2 Production of nickel-cobalt-metal battery cells and Converted Michigan facil- Inc. (Holland, Mich.; packs, as well as production of battery separators (by ity to be operational by Lebanon, Ore.) partner Entek) for hybrid and electric vehicles end of 2010 A123 Systems Inc. 249.1 Manufacturing of nano-iron phosphate cathode pow- Initial public stock offering (Romulus, Mich.; der and electrode coatings; fabrication of battery coming soon Brownstown, Mich.) cells and modules; and assembly of complete battery pack systems for hybrid and electric vehicles Dow Kokam (Mid- 161.0 Production of manganese-oxide cathode / graphite Li- Battery production slated land, Mich.) ion batteries for hybrid and electric vehicles for 2011 Compact Power Inc. 151.4 Production of Li-polymer battery cells for the General Manganese spinel-struc- – LG Chem Ltd. (St. Motors Volt using a manganese-based cathode and a tured cathode material Clair, Pontiac and proprietary separator Holland, Mich. ) EnerDel Inc. (India- 118.5 Production of Li-ion cells and packs for hybrid and Initial capacity increase napolis, Ind.) electric vehicles. Primary lithium chemistries include at existing plants, followed manganese spinel cathode and lithium titanate by later purchase of new anode for high-power applications, as well as manga- facilities space nese spinel cathode and amorphous carbon for high- energy applicationsTable 1. Selected DOE grant recipients in the areas of battery, cell and materials manufacturingunder the Electric Drive and Vehicle Battery and Component Manufacturing Initiative (Source: U.S. Department of Energy)tures and Business Development at The venture plans to begin con- When operational, Dow Kokam ex-Dow. In addition, NMC cathodes have struction of an 800,000-ft2 SLPB plant pects the facility to produce enough40% higher energy density than that in Midland, Mich. this autumn. SLPBs batteries to supply 60,000 HEVs/of another cathode material alterna- will likely appear in road automobiles PHEVs annually.tive, lithium iron phosphate. in 12–18 months, Shanker projects. NMC cathode material is also the The new RecipCOM delivers diagnostics, protection and therapy for your reciprocating compressors. Spread the word!
    • Company name Award Technology Editors notes(project locations) amount (in millions of U.S. dollars)General Motors 105.9 Production of high-volume battery packs for the GM Chevy Volt anticipated toCorp. (Brownstown, Volt. Cells will be from LG Chem and other cell provid- be launched at the end ofMich.) ers to be named later 2010Saft America Inc. 95.5 Production of Li-ion cells, modules and battery packs New plant to make Li-ion(Jacksonville, Fla.) for industrial and agricultural vehicles and defense batteries for military, avia- application markets. Primary chemistries include tion, energy storage nickel-cobalt-metal and iron phosphateCelgard LLC – Poly- 49.2 Production of polymer separator material for Li-ion Funding will help expandpore (Charlotte, batteries existing plant and buildN.C.; Aiken, S.C.) new oneToda America Inc. 35 Production of nickel-cobalt-metal cathode material for Experienced metal oxide(Goose Creek, S.C.) lithium-ion batteries producerChemetall Foote 28.4 Production of battery-grade lithium carbonate and Raw material productionCorp. (Nev.; N.C.) lithium hydroxideHoneywell Interna- 27.3 Production of electrolyte salt (lithium hexafluorophos- First U.S. producer of LiPF6tional Inc. (N.Y.; Ill.) phate, or LiPF6) for Li-ion batteriesBASF Catalysts LLC 24.6 Production of nickel-cobalt-metal cathode material for New plant operational in(Elyria, Ohio) Li-ion batteries 2012 choice of another DOE grant recipient. materials, explains that NMC-type BASF hopes to begin production of the BASF Catalysts LLC (Iselin, N.J.; cat- cathodes contain only about one third cathode material. alysts.basf.com) was awarded almost the cobalt in LiCoO2 cathodes, allow- Johnson Controls Inc. (JCI; Milwau- $25 million to help build a plant in ing a corresponding price reduction. kee, Wis.; www.johnsoncontrols.com) Elyria, Ohio for production of cathode NMC-type cathodes “offer the best recipient of the single largest DoE powders. Prashant Chintawar, BASF combination of cost, safety and per- award ($299 million), will produce senior manager for advanced cathode formance,” adds Chintawar. By 2012, batteries containing another layered www.hoerbiger.com Circle 18 on p. 62 or go to adlinks.che.com/23018-18 For more information please contact compressor-mechatronics@hoerbiger.com
    • Newsfrontmetal-oxide cathode — nickel-cobalt- to be available in late 2010. Compact new space that will allow capacityaluminum (NCA). Adding a small Power was awarded a $151-million to grow to 60,000 packs by 2012 andamount of aluminum improves cath- DOE grant to scale up production of 120,000 by 2015, EnerDel says.ode performance at low cost, said Mi- batteries with the Mn-spinel cathode, A different cathode technology un-chael Andrew, director of government which has better thermal stability and derlies batteries developed by A123affairs and external communications can discharge at higher current than Systems, Inc. (Watertown, Mass.; www.at JCI. Batteries with NCA cathodes cobalt oxide cathodes, but has a lower a123systems.com), which received onesatisfy customer requirements in a energy density. of the largest awards (over $249 mil-host of areas, including cost, abuse Manganese spinel cathodes are the lion) from the DOE program. A123tolerance, and peak power generation, foundation of HEV/PHEV batteries at Systems’ nanostructured lithium-iron-Andrew notes. Production will begin another DOE awardee, EnerDel Inc. phosphate cathode, based on technol-in summer 2010. (Indianapolis, Ind.; www.enerdel.com). ogy licensed from MIT (Cambridge, A manganese oxide cathode with a The company’s vehicle-suitable batter- Mass.; www.mit.edu), employs par-spinel structure also appears to have ies couple a lithium-manganese-oxide ticles an order of magnitude smallergotten a vote from a major customer. (LMO) spinel cathode with a lithium (100 nm versus 10 µm) than conven-Battery cells made by LG Chem (Seoul, titanate anode to boost power. This tional lithium cobalt oxide cathodeS. Korea; www.lgchem.com) with Mn- chemistry “provides the best power-to- material. Coupled with a proprietaryspinel cathodes will be part of battery size ratio that we’ve seen, high safety doping technique to improve intrinsicpacks assembled by Compact Power levels, and excellent cold-cranking capa- conductivity, the smaller particle sizeInc. (Troy, Mich.; www.compactpower. bility,” said EnerDel CEO Ulrik Grape. allows high discharge power and fastcom) for General Motors’ (Detroit, EnerDel’s $118-million DOE grant will recharging. Lithium iron phosphateMich.; www.gm.com) PHEV, the Chevy aid an expansion that includes increas- batteries have more favorable safetyVolt. Compact Power and its parent, ing production capacity to 20,000 HEV/ characteristics than cobalt oxide, andLG Chem, were selected as suppli- PHEV battery packs at existing facili- A123 will use its DOE award to sup-ers for the Volt, which is anticipated ties, followed later by the purchase of (Continues on p. 23) Check Valves Built � Easily � 3A Compliant: third party to Your verified. 32Ra, finer finishes Disassembled: also available. spare parts available. Check � No Pooling: eliminates the pooling found in � Retrofit: for use globe-type bodies. List. in new or existing sanitary ferrules and replaces the gasket. � Space Saving: compact; seals on ferrule ID and uses only one clamp. www.checkall.com West Des Moines, Iowa USA Phone: 515-224-2301 US Patent Numbers: 5,033,503; 6,039,073; & 6,152,171 sales@checkall.com Canadian Patent Number: 2,039,991 Since 1958 Circle 19 on p. 62 or go to adlinks.che.com/23018-1920 ChemiCal engineering www.Che.Com September 2009
    • Source: Roberts Law Group PLLC Newsfront ChemiCal plant Required if 1) the facility possesses any of the chemicals, at the threshold quantities, seCurity listed in Appendix A or 2) the facility is DHS directed to do so by DHS Top screen Not regulated Does present a Does not present Monitor high level of a high level of for material security risk security risk modifications Security Final tier Site Security Regulated Vulnerability determination Plan (SSP) Assessment (SVA) While security has long and SVA review Material been a concern for the CPI, modifications? Compliance and recordkeeping DHS reviews the SSP and conducts a facility inspection. If not approved, Submit revisedimpending changes to CFATS Top screen deficiencies must be corrected. The approved SSP is implemented have everyone’s attention Figure 1. The CFATS process is summarized in this flowchartS ecurity at many U.S. chemical fa- dix A, which lists approximately 300 plan (SSP) to DHS within 120 days. cilities is currently regulated by chemicals of interest (COI) and their Roberts says that the first 140 or so the U.S. Department of Home- individual screening threshold quanti- “final tier letters” were sent out in May land Security (DHS; Washington, ties (STQ), was published in November 2009, followed by about another 400 inD.C.; www.dhs.gov) under the Chemi- of the same year. In May 2009, a docu- June. More tier letters are forthcoming.cal Facility Anti-Terrorism Standard ment entitled Risk-Based Performance Those companies in receipt of the let-(CFATS). This rule, however, is about Standards Guidance was published. ters are now in the stage of submittingto expire next month, October 2009. This guide elaborates on the eighteen their SSPs. DHS will review the SSPsAll expectations are that CFATS will risk-based performance standards and determine compliance. However,be extended for a year, while proposed (RBPSs) that are established in CFATS, “because the regulations are perfor-modifications to the standard continue and identifies the areas for which a fa- mance-based and risk-driven, whatto be debated in the U.S. Congress. cility’s security will be examined, such ‘compliance’ means can change from As they work to comply with as perimeter security, access control, facility to facility,” says Roberts. He fur-CFATS, the chemical process indus- personnel surety (a check on personnel ther explains that denial leads to fur-tries (CPI) are keeping a watchful eye credentials) and cyber security. ther consultation and “The process ofon the Congressional proceedings that Compliance with CFATS begins with compliance [with CFATS] is continuousare leading to proposed changes in the an assessment tool developed by DHS as facilities change.” Roberts refers to aregulation.“CFATS — it is by far the called the Top-Screen, to assist DHS in chart as a quick summary of the overallmost dramatic issue affecting chemi- determining which chemical facilities CFATS compliance process (Figure 1).cal plant security today,” notes Robert meet the criteria for being high-risk.Hile, director of integrated security so- Sites possessing chemicals as listed in The big issueslutions at Siemens Building Technolo- Appendix A at or above the STQs must There doesn’t seem to be any disagree-gies, Inc. (Buffalo Grove, Ill.; www.usa. submit the Top-Screen questionnaire to ment among the CPI that securitysiemens.com/security). DHS for review. As Steve Roberts, an at- regulations are a good idea. In fact the torney who specializes in CFATS issues Society of Chemical ManufacturersCFATS in action (Roberts Law Group PLLC; Houston; and Affiliates (SOCMA; WashingtonCFATS has come a long way in a short www.chemicalsecurity.com) explains, D.C.; www.socma.com) commends thetime. The approval of the DHS Appro- those facilities deemed high-level risk U.S. Senate for approving legislationpriations Act in October 2006 gave the are then required to submit a security that would extend existing chemicalDHS authority to regulate the security vulnerability assessment (SVA), after security standards for one year. Theof high-risk chemical facilities. CFATS, which a facility is categorized into a American Chemistry Council (ACC;the implementing regulation, was pub- final risk tier. These facilities must Arlington, Va.; www.americanchemis-lished in April 2007 and its Appen- then develop and submit a site security try.com) notes that security has long ChemiCal engineering www.Che.Com September 2009 21
    • ADT Advanced Integration Newsfrontbeen a priority for its members, who Figure 2. Ground retract-have invested about $8 billion on fa- able automobile barriers (GRAB) stop the unauthorizedcility security enhancements under entry of vehicles up to 15,000ACC’s Responsible Care Security Code. lb, traveling at speeds up to 50In a recently issued statement, Marty miles per hourDurbin, ACC’s vice president of FederalAffairs says, “We believe the ongoingimplementation of the Chemical Fa- it is appropriate for DHS to encourage lowed. Jensen says that the ACC feelscility Anti-Terrorism Standards dem- the use of IST, but it should be on a vol- adamantly that it is not necessary foronstrates a smart and aggressive ap- untary basis, possibly with incentives courts to get involved. SOCMA’s All-proach to both securing and protecting (not necessarily financial) to facilities mond notes that a citizen suit provi-the economic viability of this essential that implement it. SOCMA’s opposi- sion is common in environmental law,part of the nation’s infrastructure.” tion to mandatory IST is founded on but it doesn’t even seem feasible in a There also doesn’t seem to be any dis- several fronts. First, IST within a se- security framework since the details ofsension “on the Hill” about extending curity framework is already addressed a facility’s security plan would not beCFATS. As she addressed the approxi- by two other well-entrenched regula- accessible to the public because theymately 350 participants at the 2009 tions: 1) the U.S. Environmental Pro- are deemed CVI (chemical-terrorismChemical Sector Security Summit held tection Agency’s (EPA) Risk Manage- vulnerability information), which isin Baltimore, Md. on June 29 to July 1, ment Program Rule (RMP); and 2) the confidential and known only to DHSHolly Idelson, majority counsel for the U.S. Occupational Safety and Health and designated facility employees.Senate Homeland Security and Govern- Admin.’s (OSHA) Process Safety Man- While the IST and civil suits issuesment Affairs Committee put it this way, agement Regulation. A great concern are the main areas of disagreement“The debate is what should the program is that a chemical deemed to be a safer between the organizations represent-be, not should there be a program.” Ms. alternative might be mandated by ing the CPI and the proposed HouseIdelson made it clear that as the Senate government officials without a full un- bill, there are other areas of discus-committee works on defining what the derstanding of the many ramifications sion. These questions include whoprogram should be, it welcomes input of that chemical substitution. should be covered in CFATS, suchfrom the CPI to let the members know Allmond uses manufacturers of active as when it comes to water-treatmentwhat is working and what is not work- pharmaceutical ingredients (APIs) as facilities and industrial versus agri-ing in CFATS, saying, “Our [the Senate an example of where unexpected com- cultural uses of ammonium nitrate.Committee’s] door is open.” plications could arise. API manufactur- ACC’s Jensen puts it into perspective, Since the clock has just about run ers go through a lengthy process of U.S. though, when he says, “We [the CPI,out for a standalone security bill this Food and Drug Administration (FDA) U.S. Congress and DHS] agree onyear, CFATS is well on its way to a approvals. If, for example, a so-called more than we disagree” including theone-year extension. It is also expected “safer alternative” compound were overall objective of having permanentthat in this upcoming year discussions mandated, this new compound might Federal chemical security regulations.about what a permanent rule should require an untenable amount of retest-look like will intensify. While the U.S. ing before the switch could occur, and it Integrators and suppliersSenate has not yet formed its own ver- might not be approved by the FDA. As tiered facilities move forward withsion of a bill, The House of Represen- The ACC also opposes mandatory their site plans, a number of companiestatives has proposed a revision to the IST. Scott Jensen, director of commu- are positioning themselves to help withcurrent CFATS standard. The details nications for ACC says that making the process of CFATS compliance andare where the dissension begins. IST mandatory in a security regula- implementation. Hile says that Siemens Bill Allmond, vice president of Gov- tion brings “discomfort and concern can help “from start to finish”, offeringernment Relations and ChemStew- for facility operators since determina- “assistance from the very early stagesards for SOCMA explains that the two tion is based on one factor, whereas all the way through to the implementa-main points in the House’s bill that a facility makes that determination tion.” One form of assistance is a sur-SOCMA opposes are: 1) mandated in- based on many factors.” Jensen states vey package that helps to break downherently safer technologies (IST); and simply that ACC’s position is that “it CFATS into “layman’s” terms giving a2) a civil suits clause. is not necessary to include [manda- facility a sort of template to help form IST encompasses a wide breadth tory] IST” in the security bill because the SVA, and then further down the lineof chemical processing procedures, the current CFATS program allows for to help with the plan (SSP). Siemens isequipment, protection and the use of and encourages IST implementation. poised to offer an array of surveillancesafer substances. Allmond states that Both SOCMA and the ACC also products and perimeter-intrusion-de-SOCMA “adamantly opposes manda- oppose the civil suits clause in the tection systems. The majority of RBPSstory IST” and more to the point “What House’s proposed legislature, which in CFATS deal with the physical secu-SOCMA opposes the most is getting would allow any citizen to sue a com- rity of a site, so these types of productsinto [mandatory] chemical substitu- pany if their perception is that the are expected to be an important part oftion.” He explains that SOCMA agrees CFATS regulation is not being fol- a site’s security plan.22 ChemiCal engineering www.Che.Com September 2009
    • Andrew Wray, senior global market- have been around for some time, but at the Dow Chemical Co. puts it, “In se-ing manager with Honeywell Process never utilized in the private sector curity you have a purposeful, intelligentSolutions (Phoenix, Ariz.; www.honey- the way they are now,” says Loughin adversary. How do you measure that?”well.com) says that to achieve increas- as he gives examples of fiber-based Still, Cosman and his colleagues on theing levels of security, more and more fence detection, thermal imaging, ISA99 Committee, with contributionstechnology needs to be integrated. video analytics and radar. “I believe from other groups, such as ACC’s ChemHoneywell is well-positioned to offer the day of the six-foot chain-link fence ITC, are making headway in definingintegration with a single system for is over for the highest-risk facilities,” cyber-security standards that will becontrol, he adds. Looking ahead, Wray he says, citing that K-rated and high- applicable to a broad industry base. Asays that “as more and more systems security-fencing and barrier technol- concept gaining momentum is the de-are integrated into the network, more ogy are now being used (Figure 2). velopment of security assurance levelsproducts need to make decisions ‘at Loughin notes that ADT has Safety (SALs), comparable to SILs. Cosmanthe edge’.” To explain what he means (Support Anti-terrorism by Fostering says that the “SAL concept has a lotby at the edge, Wray gives the example Effective Technologies) Act Certifica- of promise. It is going to get us some-of a card reader at a facility perimeter. tion for electronic security services. where, I just don’t know how far.”While the card reader likely has local This DHS-designated certification is John Cusimano, director of se-decision-making capabilities, new a way to manage the risk of liability, curity solutions for exida (Sellers-technology is emerging that will check says Roberts, who advises companies ville, Pa.; www.exida.com) explainsthe integrity of the reader’s data prior to consider Safety Act protection as a that it has been a long process, butto gaining access to the network. factor when selecting a security ven- the IT security and control-system “Integration of multiple technolo- dor during the procurement process. communities have successfully co-gies is key,” agrees Ryan Loughin, di- operated to develop cyber standardsrector of the Petro-Chem and Energy The cyber side and methodologies, and that “Re-Div. of ADT Advanced Integration While the bulk of CFATS focuses on cently the safety system community(Norristown, Pa.; www.adtbusiness. the physical plant, it also addresses has joined this effort, bringing [its]com/petrochem-ce). He goes on to say cyber security, which is undoubtedly proven risk-mitigation engineeringthat “The overall security philoso- an integral part of overall security. methods to the table.” Among otherphy at a plant is changing. Security Part of the issue with regulating cyber services, exida offers a Control Sys-is now a program much like safety security is how to quantify what level tem Security Assessment to reviewhas been for years…CFATS is driv- of cyber security one needs, or has. Ex- the cyber-security environment of aing this program-related process.” perts are using their experience with facility and compare it with indus-Loughin explains that a tiered facil- safety standards to focus on this issue. try best practices with recommen-ity faces two basic threats: toxic re- In the safety arena, metrics can be dations to address possible gaps. Aslease, and theft and diversion. ADT’s assigned according to probability on a momentum increases in the efforts toapproach to working with a facility scale of safety integrity levels (SILs; see standardize cyber security, everyonewith one or both of these threats is CE, Sept. 2007, pp. 69–74). Assigning seems to agree in the prediction thatto consider three key factors: deter, metrics to security, however, poses a big- it will become a more integral part ofdetect and delay. “Many of the tech- ger challenge. As Eric Cosman, co-chair future security regulations. ■nologies being used on these facilities of the ISA99 Committee and who works Dorothy LozowskiCPI EnErgIzEd consortium headed by the Karlsruhe (Suwon, S. Korea; www.samsungsdi. (Continued from p. 20) Institute of Technology (Karlsruhe, com) was selected by BMW (Munich;port construction of a Michigan facil- Germany; www.kit.edu) to develop www.bmw.com) to supply Li-ion batter-ity to produce battery component ma- novel battery materials that will in- ies for its “Megacity” electric vehicle.terials, battery cells and battery packs crease energy density in cells intended Even as commercial production offor HEVs and PHEVs. for electric vehicles. Li-ion batteries draws near, indus- Private sector players in Europe are trial R&D moves forward on severalEuropean battery activity positioning themselves for the advanced fronts, including exploring new elec-While the U.S. DOE grant program was battery market as well. Evonik Indus- trode material combinations andgrabbing attention in August, efforts tries AG (Essen, Germany; www.evonik. structures, as well as processingto develop batteries for HEVs/PHEVs com) and Daimler AG (Stuttgart, Ger- improvements to lower cost and im-continued elsewhere. In July, the Euro- many; www.daimler.com) established a prove consistency and quality. At thepean Commission (Brussels, Belgium; development and production partner- same time, academic laboratories areec.europa.eu) identified “high-density ship and launched plans to construct further investigating the applicationbatteries” as a priority in its funding a Li-ion battery plant in Kamenz, Ger- of nanoscale engineering to electrodeto develop HEVs and PHEVs. many. Production will begin in 2011. materials, reaction dynamics on elec- With €20 million from its own eco- SB LiMotive, a joint venture of Robert trode surfaces, novel electrode mate-nomic stimulus package, the German Bosch GmbH (Gerlingen, Germany; rials and electrolytes. ■government is setting up a research www.bosch.com) and Samsung SDI Scott Jenkins ChemiCal engineering www.Che.Com September 2009 23
    • Solids ProcessingMeasuringDust and Fines FIGURE 1. Many types of dustIn Polymer Pellets and fines form during the han- dling of bulk plastic pellets. A single pellet is shown here for size comparison 9 100 The ability to carry out 8 90 such measurements can 80 Cumulative fraction, vol. % Differential fraction, vol. % 7 help operators improve 6 70 60 quality control, assess 5 50 equipment performance 4 40 3 and optimize the process 2 30 20 1 10Shrikant Dhodapkar 0 0Remi Trottier 10 100 1,000 10,000Billy Smith Particle size, micrometersThe Dow Chemical Co. FIGURE 2. Pneumatic conveying systems routinely create dust and fines when moving polyethylene pellets. The size distribution shown here was measured using an image analyzerP lastics are most commonly collection in cyclones (Figure 1). The nants in pellets can lead to numerous produced and sold in pellet particle size distribution of dust and problems in the downstream pro- form due to the superior han- fines (Figure 2) can vary depending cesses, including the following: dling characteristics of pellets on type of polymer, process condi- 1. Gel formation in film applicationsin downstream applications. From tions and specific hardware of the 2. requent clogging of filters in pneu- Fthe moment the polymer is pelletized handling system matic conveying systemsfrom its molten state, the pellets or • hips, undersize pellets, miscuts C 3. ross-contamination problems in Cgranules undergo a series of handling and broken fragments that are gen- multi-product plantssteps as they move from the producer erated during pelletization, convey- 4. Defects in the finished productto the consumer. For instance, post- ing and collection in cyclones 5. ariability of slip additives or pro- Vpelletization steps include: • hopped or smashed pellets, C cessing aids• Hydraulic conveying so-called worms or smeared polymer 6. olor issues (such as black specks or C• Drying (typically via spin drying) crumbs that are generated by rotary color inconsistencies) resulting from • In-process pneumatic conveying airlocks (feeders) degraded fines dislodging from pro-• Silo storage • roken B tails that result cess equipment• ackaging (via bulk shipment, or in P from poor pelletization and 7. rocess safety issues (such as in- P bags or boxes) subsequent handling creased risk of dust explosion in the • nloading (via pneumatic convey- U • treamers, floss, angel hair, rib- S fines-collection system) ing) and silo storage bons or snake-skins that are gener- 8. ndustrial hygiene concerns associ- I• Conveying to processing equipment ated during pneumatic conveying ated with respirable dust• Blending and feeding (Figure 3) 9. lugging problems at various stages PAs a consequence of this repeated Many of the terms noted above are of the end user’s process, resultinghandling, the pellets often become synonymous and thus are used inter- from streamers, floss, angel haircontaminated with various unwanted changeably, based on the shape and and ribbonsspecies, namely: size. Streamers can be up to a couple 10. Inconsistent pellet feedrates into • ust or fines that are generated D of meters in length. he throat of an extruder, resulting in t during pelletization, conveying and The presence of these contami- gage variations of profiles and films24 ChemiCal engineering www.Che.Com September 2009
    • Dust / fines Tails and short streamers counterflowing air. This method is quick but usually results in relatively poor separation efficiency and high variability. Separation via air classifi- cation can also be affected by the rela- 12 in tive humidity of the elutriation air. By contrast, wet classification is theFIGURE 3. The steamers, floss, angel hair andribbons shown here are examples of the types most effective method for separation ofof impurities that typically form when plastic Group 1 species from pellets and gran-pellets are pneumatically conveyed ules. Dispersing the pellets in a liquid or washing them with a liquid breaksFIGURE 4. This illustration shows how the separation of fines, down the attractive forces betweentails and short streamers can be improved when the wet separa- Water flow with the fines and the pellets, thereby al-tion process incorporates a screen with elongated apertures lowing them to then be easily removed bubbling air by mechanical separation. However, To alleviate these problems and de- charges, the existence of waxy and this approach adds a drying step toliver the cleanest possible product to sticky additives, and the presence the measurement process.the customer, many of today’s plastics of fines at particularly small Demineralized water, ethanol orproducers use dust- and streamer- particle sizes (< 50 µm) and low levels a mixture of water and ethanol areremoval devices in their processes. (< 50 ppm). commonly used for washing. Safe han-Further discussion of these devices is This article summarizes the exist- dling characteristics and inertness tobeyond the scope of this article. ing standards for quantifying un- the polymer (and its additives) are key Efforts to quantify the unwanted wanted contaminants such as dust, considerations when selecting the liq-species in the plastic pellets have fines and streamers in plastic pellets, uid washing media.long been a source of confusion, discusses the limitations of these ap- Group 2 species are the most dif-contention and miscommunication proaches, and highlights some of the ficult and challenging to separateamong plastic producers, users of recent advances. from the pellets, since most separa-the pellets (converters) and vendors tion techniques rely on differences inof solids-handling equipment. Such Measurement techniques particle size. The air-classification ap-problems can be avoided if there is In general, unwanted species contami- proach can be used if the aerodynamicmutual agreement by all stakehold- nating a batch of plastic pellets can be diameters of various fractions are sig-ers on an appropriate standard for broadly classified into three groups, nificantly different and electrostaticthe measurement of dust, fines and based on their size relative to the forces are minimal.streamers. A reliable, robust and well- pellets or granules (the prime One may also exploit the differencesdocumented standard serves a variety product) themselves: in shape for separation. For instance, aof purposes including the following: • roup 1 (size < pellets). Fines, dust, G new, innovative approach has been de-• nsures greater quality control in a E chips, fragments, undersize pellets, veloped by the authors of this article, manufacturing process miscuts, smears, worms and ill- to effectively separate Group 2 species• rovides a basis for product P formed pellets from plastic pellets. The core idea is to specification • roup 2 (size ~ pellets). Tails, G use a rectangular aperture (such as a• erves as a troubleshooting tool to S smears, worms and small streamers wedge-wire screen) coupled with a wet relate pellet quality with process • roup 3 (size > pellets). Stream- G washing approach, to separate the pel- conditions ers, floss, angel hair, ribbons and lets from the unwanted species.• elps to identify opportunities for H snake skins The width of the aperture is slightly process optimization Group 1 species can typically be sep- smaller than the diameter of the pel-• nables performance evaluation of E arated from the pellets by dry siev- lets, which prevents them from pass- pellet-cleaning devices ing or air classification if there is no ing through. However, the longer di-A varied and creative collection of tendency for the particles to adhere mension of the aperture allows thedust- and fines-measurement tech- to the pellets, for instance, due to tails, polymer smears, agglomeratesniques have evolved over the years electrostatics, van der Waals forces, and small streamers that are longerbased on experiences derived from a surface tension and other adhesive than the pellet size to pass through,wide spectrum of applications. His- tendencies. Anti-static additives are along with the wash liquid (Figure 4).torically, these techniques have been used to minimize the electrostatic Group 3 species are most effec-based on dry sieving or counter-flow buildup. However, dry sieving is tively separated by dry screening. Theair-classification concepts. often unable to separate sticky fines screener can be a vibrating type, or a However, for plastics applications, (such as those that are rich in Trommel (rotating cylinder) type. Forthe quality of data gathered using waxy additives). a meaningful estimation, the samplethese methods is often compromised, Using an air-classification approach, size must be large enough to capture adue to the presence of electrostatic the finer fraction is elutriated by the sufficient number of streamers. ChemiCal engineering www.Che.Com September 2009 25
    • Solids Processing Column C2 Column C1 Outlet, open only when*Existing standards FIGURE 5. TheToday, there are three primary stan- elements of the wet process that is de-dards for measuring fines in plastic fined in FEM-2482pellets or granules, and each is dis- Overflow pipe Column head are shown herecussed below: Retention• EM-2482: Test method to de- F sieve* termine the content of fines and streamers in plastic pellets (1999) Retention• STM D 1921-06: Standard test A medium Contaminated for fines product method for particle size (sieve anal- classification ysis) of plastic materials (2006)• STM D 7486-08: Standard test A method for measurement of fines and dust particles on plastic pellets Support sieve by wet analysis (2008)FEM-2482 Column footThe European Federation of MaterialsHandling (FEM) put forth a well-docu- Air Fluid supply*mented and comprehensive procedure pump Throttle Air(FEM-2482) in 1999 to address the valve filter*ambiguity associated with measuringfines and streamers in plastic pellets.In this standard, the fines are defined M Flowmeter Throttle valve*as the particle fraction below 500µm. The lower limit of this fraction * Only if flotation mode 2 is useddepends on the needs of downstreamprocesses. Three classes of fines were wet process with two possible operat- retention sieve shown in Figure 5 is aproposed, namely: ing modes. 500-µm wire mesh that prevents the• Type A: 63 to 500 µm Mode 1. Fluidization mode is used pellets from being carried over to Col-• Type B: 45 to 500 µm when the density of washing liquid is umn C2.• Type C: 20 to 500 µm lower than the true density of the pel- The FEM-2482 standard also pro-The process schematic for measure- lets. A retention sieve (Figure 5) is not vides details on various aspects of thement of fines using FEM-2482 is used in Column C1 during fluidiza- measurement process, such as:shown in Figure 5. tion mode. The upward velocity of the • izing and configuration of S When it comes to plastic pellets, the liquid is set according to the Stokes the apparatustypical level of fines in the final prod- velocity for the largest particle to be • Selection of classification screensuct can range from 10 to 2,000 ppm. separated. The carryover fraction is • Ancillary equipmentPellets with fines content in excess of further classified in Column C2. • election of guidelines for S500 ppm are usually deemed “dusty.” It Mode 2. Flotation mode is used when wash liquidshould be noted that the fines fraction the density of the washing liquid is • Test procedurebelow 20 µm is not measured by this higher than the density of the pellets. • Interpretation of results method, since this ultrafine fraction Since water is the safe choice as the • Error analysispasses through the retention medium washing liquid for most polyolefins pel- Sampling guidelines per FEM-(Column C2). However, the ability to lets whose density is lower than water, 2482). A sample size of 1 L or largermeasure this fraction can be impor- this mode is most commonly used. is recommended for fines analysis.tant for certain applications (such as Using the FEM-2482 method, the As a general rule of thumb, the maxi-the manufacture of optical lenses and agitation and circulation of pellets are mum size of a sample is dictated bydigital storage media). achieved by injecting air bubbles in the size of the washing column (C1). The particle fraction above 500 Column C1. The intensity of circulation To achieve good dispersion and wash-µm with a form deviating from the can be adjusted by the air-flow throttle ing, the volume of a sample should notusual pellet shape is defined as the valve (Figure 5). The authors of this exceed half the volume ofstreamer content. Streamers are also article have evaluated numerous alter- Column C1.known by numerous other names natives for mixing and agitation (such For streamer content analysis con-— angel hair, floss, snake-skins, rib- as the use of directional water jets and ducted using the dry-screening ap-bons, film or foil. As noted earlier, agitators) and have concluded that the proach, the sample volume should bedry screening is an effective way to use of air bubbles is the most effective at least 50 L. Since streamers are notseparate these species from pellets. means of agitation and recirculation dispersed homogenously within the The FEM-2482 method is based on of pellets in the wash column. The top bulk, larger samples are always pre-26 ChemiCal engineering www.Che.Com September 2009
    • FIGURE 7. As noted in the in FEM-2482 wet process, a wedge-wire screen with elongated aperatures (right) is a more-effective alternative to the standard 500-μm 5 cm retention screen (left).FIGURE 6. A typical pellet with a tail formedduring pelletization is shown in the inset, whilethe larger image shows the typical size distribu-tion of broken tailsferred. Note that this standard lacks the fines, tails and small streamers buildup during dry sieving is ad-details regarding methods and devices to efficiently pass through. The tails dressed by adding an anti-static addi-to use for separation of streamers from and small streamers align themselves tive (up to 1 wt.%). However, the prob-the pellets. with the liquid flow and pass through lem of sticky fines and agglomerates Special care must be given when the rectangular aperture (Figure 4). is not addressed in this standard andhandling samples during filling, dis- Alternatively, a punched plate with thus remains unresolved.charging and transportation. The elongated openings can also be used. One fundamental problem withmethodology of sampling depends on However, the use of square wire-mesh separation processes using sievesproduct and plant surroundings. with larger opening inevitably results is the inherent inefficiency of sieve-Limitations of FEM-2482. Despite in occlusion of the openings as the tails based separation methods to separatethe comprehensive nature of this and streamers hang up on the mesh. fibrous fines that are longer than thestandard, it has several shortcomings, The wedge-wire retention screen mesh opening size, even if the fiber di-including the following: also allows chips, undersize pellets, ameter is much smaller.1. Fines smaller than 20 µm in size miscuts and broken pellet fragmentsare not measured or collected by the to pass through and get carried over to ASTM D 7486-08finest retention medium (Column C2). Column C2 (Figure 5). Therefore, it is This is a recent addition to the stan-The limit on the lower cut is due to recommended that the fines classifica- dards for fines and dust measurementphysical limitations posed by the tion screen-stack (Figure 5) preferably in plastic pellets. It proposes a wetscreening operation. have a top sieve with 1-mm opening. washing technique. The sample (typi-2. In this standard, fines are defined The remainder of the sieves can be cally 100 g) is placed on a filter funnelas the fraction with particle size chosen per the FEM-2482 guideline. assembly, consisting of a 200-mm diam-smaller than 500 µm. However, par- eter, wire-cloth sieve with 500-µm open-ticles with size greater than 500 µm ASTM D 1921-06 ing. The filtration disc (90 mm in dia.) iscan exist in the fines (Figure 2). Dry This method covers the measurement made of glass microfiber, and the mediascreening may not be the appropri- of particle-size distribution of plastic has a pore size of 0.7 µm to 2.7 µm. Theate method for separating these fines materials in various forms — pellets, typical lower limit is 1.6 µm due to fil-from the pellets, especially when the granules and powders. It is based on tration rate limitations.fines are sticky, waxy and specifically the dry-sieving approach, hence the The pellets are washed with a strongfibrous in nature. Similarly, quantifi- lower limit of measurement is about jet of water (500 mL/min) until theycation of broken tails with size vary- 38 µm (No. 400 sieve). are visibly clean and no particles areing from a fraction of the pellet size to The standard proposes two methods observed in the wash liquid. The filterseveral pellet diameters is especially — A and B — both of which are dis- disc is then removed from the assem-challenging (Figure 6). Typical pellet cussed below. bly, dried in an oven and then weighedsize is between 3 and 5 mm. Method A. This method uses multiple to measure the fines content. The first limitation has been ad- screens stacked on top of each other. A This method addresses the defi-dressed by a recent ASTM standard complete distribution of particle sizes ciency of FEM-2482 in its inability(D 7486-08, discussed below), which can be obtained, which can then be used to quantify fines smaller than 20 µm,recommends using a filtration disc to determine the mean particle diame- since fines as small as 0.7 µm can bemade of glass microfibers to collect ter. The suggested sample size is 50 g. captured on the filter disc. However,fines as small as 0.7 µm. Method B. This is an abbreviated smaller sample size (100 g) and pos- The second limitation can be ad- version of Method A that uses lim- sible operator dependence for effectivedressed by replacing the 500-µm wire- ited screens. It is typically used to get washing of pellets are the shortcom-mesh retention screen (shown in Fig- specific cuts (such as percent passing ings of this method.ure 5) with a wedge-wire screen (see through, or the percent retained) on When streamers (such as a fractionFigure 7). The rectangular aperture certain screens. The suggested sample greater than 500 µm) are present, theof the wedge-wire screen is designed size is 100 g. standard proposes using the ASTM Dto retain the pellets while allowing The problem of electrostatic charge 1921-06 method. ChemiCal engineering www.Che.Com September 2009 27
    • Table. Summary of fineS-meaSuremenT TechniqueS and STandardS fines/dust mea- Pros cons applicability surement method Dry sieving Easy to implement Loss of fines during handling Suitable for coarse (ASTM D1921-06) Inexpensive Poor separation if electrostatic or fines (> 500 μm) adhesive forces are present Fibrous fines longer than sieve opening do not separate effectively Small sample size Air classification Short test duration Accuracy affected by air humidity Excellent qualitative test (Fluidized beds, Good for qualitative testing and static generation Generally not recommended for zig-zag classifiers) Does not remove fines effectively polymer fines measurement when the adhesion forces are present More suitable for non-polymer Poor recovery of separated fines applications Wet separation Robust method Upper and lower cuts on particle Applicable for most process Operator independent size are restrictive polymers (FEM-2482) Sample size is limited for Well defined procedure commercial units Commercial equipment available Fibrous fines longer than sieve opening do not separate effectively Wet separation Robust method Limitation due to lower cut size Wider applicability process Operator independent (20 μm) still remains than original method (Modified FEM-2482 sith Well defined procedure wedge-wire Eliminates the limitation on retention screen) upper cut (500 μm) for fines Wedge wire enables efficient separation of broken tails Wet sieving Address lower cut size limita- Small sample size For applications where (ASTM D7486-08) tion of FEM-2482 down to Washing is manual and may not fines less than 20 μm 0.7 μm remove strongly adhered fines are important Commercial equipment Fibrous fines longer than sieve available opening do not separate effectively The methods discussed above are FIGURE 8. Thissummarized in Table 1. The applica- 0.7 20 38 500 ~10 figure shows μm μm μm μm mm the range of ap-bility range for each method based on plicability for theparticle size is shown in Figure 8. Particle size various measure- ASTM D 7486-08 ment standardsTips for success Wet analysis discussed here,To ensure maximum reliability during ASTM D-1921 based on particle sizemeasurement of fines or dust in plas- Dry screeningtic pellets, readers are encouraged todo the following: FEM-2482• nderstand the nature and content U Wet analysis Dry screening of typical non-pellet fraction (such Modified FEM-2482 as fines, dust, streamers) in the bulk material Wet analysis Dry screening• dentify the key requirements for I Typical size range downstream processes and be clear pellets and granules about the purpose of the mea- 1 – 5mm surement (for instance, are the measurements being sought to reduce process variability, meet Readers should note that obtaining a large sample from the process and re- product specification, assist in “representative sample” for fines and duce it to the appropriate analytical troubleshooting or optimize equip- dust analysis is a difficult task that size using a sample splitting process ment performance?) presents its own challenges. Specifi- (such as a riffler). However, one must• dentify the most suitable test I cally, the samples inevitably become pay close attention to the loss of fines method(s) for the purpose, and es- biased, due to the attraction of fines during this step, otherwise the results tablish specific testing parameters towards any sampling device or sam- will be biased. Purging the sampling based on the material at hand pling container. For example, the use line before taking the sample, taking• nderstand the accuracy, precision U of a plastic scoop can result in signifi- spot samples to create a composite, and reproducibility of the chosen cant loss of fines from the sample, due analyzing the entire sample, rinsing test method to electrostatic attraction between the the sample container to recover fines• btain representative samples and O fines and the scoop itself. and the use of anti-static sprays will follow good sampling guidelines It is a common practice to obtain a help to reduce sampling errors.28 ChemiCal engineering www.Che.Com September 2009
    • Solids ProcessingClosing thoughts During the past decade, signifi- processes. The success of these stan-One of the key metrics of product qual- cant progress has been made toward dards hinges upon the user’s under-ity for polymer pellets is the amount of the standardization of measurement standing of the underlying conceptsfines, dust and streamers that are gen- methods available to quantify these and careful attention to the details.erated during handling. The presence unwanted contaminants. These stan- In this article, the authors have alsoof such unwanted species has a direct dards provide a common basis for introduced an innovative approach tobearing on downstream applications, evaluating product quality, for assess- measure tails and short streamers inand therefore to the acceptability and ing the performance for pellet-clean- the pellets. ■value of the final product. ing systems, and for troubleshooting Edited by Suzanne ShelleyAuthors Shrikant Dhodapkar is a Remi Trottier is a senior Billy Smith is a senior re- technical leader in the Dow specialist in the Solids Pro- search chemical technologist Elastomers Process R&D cessing Discipline of Engi- in the Fluid and Mechanics Group at The Dow Chemi- neering & Process Sciences Mixing Group in Engineer- cal Co. (Freeport, TX 77541; at The Dow Chemical Co. ing and Process Sciences Phone: 979-238-7940; Email: (Phone: 979-238-2908; Email: at The Dow Chemical Co. sdhodapkar@dow.com) and ratrottier@dow.com). He re- (Phone: 979-238-2097; Email: Adjunct Professor of Chemical ceived his Ph.D. in chemical BGSmith2@dow.com). He re- Engineering at the University engineering from Loughbor- ceived his Bachelors degree of Pittsburgh. He received his ough University of Technol- in Applied Technology in In- B.Tech. in chemical engineer- ogy, U.K,, and M.S. and B.S. dustrial Management and an ing from I.I.T-Delhi (India) degrees in Applied Physics Associate of Science degree inand his M.S.Ch.E. and Ph.D. from the University at Laurentian University, Sudbury, Ont. He has physics and chemistry. For the past 10 years, heof Pittsburgh. During the past 20 years, he has more than 20 years of experience in particle char- has worked on numerous projects related to fluidpublished numerous papers in particle technology acterization, aerosol science, air filtration and sol- mechanics and mixing technology. He has exten-and contributed chapters to several handbooks. ids processing technology. He has authored some sive laboratory experience in both lab equipmentHe has extensive industrial experience in powder 20 papers, has been an instructor of the course and wet chemistry.characterization, fluidization, pneumatic convey- on Particle Characterization at the Internationaling, silo design, gas-solid separation, mixing, coat- Powder & Bulk Solids Conference/Exhibition foring, computer modeling and the design of solids the past 15 years, and has authored an article onprocessing plants. He is a member of AIChE and particle characterization for the “Kirk-Othmerpast chair of the Particle Technology Forum. Encyclopedia of Chemical Technology.”Circle 21 on p. 62 or go to adlinks.che.com/23018-21 Circle 22 on p. 62 or go to adlinks.che.com/23018-22 ChemiCal engineering www.Che.Com September 2009 29
    • September 2009 CHe.COm Literature ReviewFeaturing Brochures and Catalogs of Products and Services for the CPI Visit CE Lit Online at che.com EquipNet provides asset management ser- BWB Technologies vices to world-class chemical companies Model XP Flame Photometer Our offerings include asset The BWB- XP is a high quality, high perfor- evaluation and appraisal, site mance instrument employing modern technol- reconfiguration consulting, ogy to measure alkali and alkaline earth met- project management, and sales als Sodium (Na), Potassium (K), Lithium (Li), and marketing. These services Calcium (Ca) and Barium (Ba). Liquid samples, yield a large supply of high- when introduced to a flame fuelled by pro- quality process equipment and pane or lpg, will emit light of a specific wavelength, the intensity of unused MRO parts available for which will be proportional to the concentration of the ions present. sale at the EquipNet Market- The principle has been understood for over one hundred years, but Place™, the largest website of its kind. Contact: E.J. Paturzo, the BWB-XP brings 21st century technology to the technique, mak- Managing Director: Chemical (781) 821-3482 x100 ing analysis more reliable, accurate and simple than ever before. epaturzo@equipnet.com www.EquipNet.com BWB Technologies www.bwbtech.com/ce Circle 290 on p. 62 or go to adlinks.che.com/23018-290 Circle 291 on p. 62 or go to adlinks.che.com/23018-291 These railcar movers are best for NEW 3 Inch Stainless Steel small to mid-size applications 2-Way Solenoid Valves The CUB® Railcar Mover is designed Magnatrol now offers its popular Stainless Steel to move one railcar or a group of railcars Solenoid valve in a 3 inch size. Full port; require safely. It moves along a steel runway utiliz- NO differential pressure to open and are easily ing a carriage assembly without dangerous serviced while in the pipeline. Applications in- wire ropes. Two pivoting arms securely cap- clude Deionized Water, Ammonias, Vegetable ture the railcar truck frame. A variable speed motor drive powers Oil, Fuel Oil, Gas, Steam, Solvents, Cryogenics a chain and sprocket arrangement that allows the CUB to travel in and Oxygen. Valves are of a packless con- a swift bi-directional manner. Safe, easy to install and operate, the struction with continuous duty coils for all AC and DC voltages, CUB is ideal for small to mid-sized railcar loading, unloading and available normally open or normally closed with 150 and 300lb repositioning. H&P offers a complete line of railcar movers from 1 flanged connections. For literature or same day quotation contact: railcar to a complete train. Visit us at www.heylpatterson.com MAGNATROL VALVE CORPORATION PHONE: 973-427-4341 P 412-788-9810 F412-788-9822 E info@heylpatterson.com E-MAIL: info@magnatrol.com WEB SITE: www.magnatrol.com Circle 292 on p. 62 or go to adlinks.che.com/23018-292 Circle 293 on p. 62 or go to adlinks.che.com/23018-293 Midwesco® Launches One Piece ALL 316SS Solenoid Valve up to 6” Pipe Size Molded Bottom Pleated Bag All wetted components are made from 316SS. This rotary shaft New Pleat+Plus® Molded Design Eliminates Abrasion type solenoid valve completely isolates the fluid from all magnetic Issues Compared to Traditional Metal End Caps. solenoid components. Easily handles cor- Midwesco®’s customers indicated that they rosive or viscous fluids. Available in ½” to 6” desired an improvement in the traditional pipe sizes. For literature or same day quota- metal end cap in the pleated bag design. The tion contact: traditional metal end cap can create abrasion CLARK-COOPER DIVISION in the recess as well as shrinkage and chem- Magnatrol Valve Corporation istry fluctuations between the potting compound 855 Industrial Hwy - Unit # 4 and the end cap. Midwesco®’s new molded bottom integrates a Cinnaminson, NJ 08077-1933 universal pleat spacing and inner core rest-up while improving our Phone: 856-829-4580 - Fax: 856-829-7303 interlocking adhesive seal. Contact: Darlene Lowman Midwesco® E-Mail: techsupport@clarkcooper.com Filter Resources, Inc. Phone 800-336-7300 Fax 540-667-9074 Website: www.clarkcooper.com Circle 294 on p. 62 or go to adlinks.che.com/23018-294 Circle 295 on p. 62 or go to adlinks.che.com/23018-295
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    • Heat Transfer: System Design II Department Editor: Scott JenkinsEXPANSION TANK satisfactorily by relatively simple “on-off” attention must be paid to achieving turbu- or “high-low” controllers. However, units lent flow (without stagnation zones) aroundA well designed expansion tank: of all sizes will operate more uniformly if the heat transfer surfaces to eliminate hot1. Maintains a static pump-suction head equipped with modulating temperature con- spots and localized fluid boiling.2. Compensates for temperature-related trols. Install user controls to regulate the flowvolume and pressure changes of the heat transfer fluid in proportion to VALVES3. Provides a means of venting moisture the energy consumption of the equipment.and low boilers Cast- or forged-steel valves with 13-chrome In a multiple-user system, separate controls4. Prevents fluid oxidation trim are satisfactory for service in organic should be installed on each consuming unit Usually, the expansion tank is installed heat-transfer-fluid systems. Globe valves to assure the proper energy delivery.at the highest point in the system and is with an outside screw (as a protectionconnected to the suction side of the pumps. FIRE RESISTANCE against high temperatures) should be usedIt should serve as the main venting point of throughout the system when tight sealing ofthe system, as well as provide for system Materials considered NOT fire-resistant: fluids is desired, and should be installed up-fluid expansion, which can be 25% or • ow melting point metals: aluminum, L stream and downstream of each pump andmore depending on fluid choice and on the copper at each user. Gate valves are acceptableoperating temperature range. For heat- • lastomers E for use, but not to provide reliable positiveing circuits, the expansion tank should be • olytetrafluoroethylene (PTFE) gaskets and P shut-off.sized so that it is one-quarter full at ambient packing The use of valve stem seals can be effec-temperature and three-quarters full when • on-asbestos, fiber-reinforced rubber N tive in minimizing system leakage. For valvethe system is at operating temperature. For bound gaskets stem seals:cooling, it should be vice versa. Materials considered fire resistant: • lexible graphite packing with inner F The double drop-leg expansion tank • igh-melting-point metals: carbon and H and outer anti-extrusion rings of braidedprovides greater flexibility of operation stainless steel, nickel alloys graphite fiber gives the best results forthan a single leg tank. From a single-leg • lexible graphite packing and gaskets F elevated temperature systems.expansion tank, venting of nonconden- • sbestos packing and gaskets A • TFE packing often works in systems Psibles is often difficult in heating systems operating up to 400°F (200°C).as is purging of air and water on startup. HEATER • etal bellows-sealed valves are frequently MA double-leg expansion tank provides unin- used with excellent results, but these Two basic fired-heater designs for indirect valves are relatively expensive, especiallyterrupted flow on startup and significantly heat transfer systems are available: liquid in larger sizes.improves the venting capability of the tube and fire tube types. • iber packing materials have given poor Fsystem. All vent lines should be routed to a • n liquid tube heaters, fluid is pumped I performance in service with organicsafe location. through the tubes as it is heated. The fire fluids, and are not recommended. Experience indicates that systems with is outside the tubes.expansion tanks open to the atmosphere • n fire tube heaters, fluid flows through the I References and further readinghave fluid contamination problems related heater “shell” around the outside of the 1. Wagner W. “Heat Transfer Technique withto oxidation and excessive moisture. There- fire tubes. Organic Media.” Grafelfing-München: Technis-fore, open expansion tanks should not be cher Verlag Resch KG, 1977. Liquid tube heaters are preferred at allemployed in systems using organic heat temperatures. At temperatures below 2. Gamble CE. Cost Management in Heat Trans-transfer fluids. fer Systems. Chemical Engineering Progress, 500°F (260°C), fire tube heaters with a An effective way to minimize fluid oxida- July 2006 pp. 22–26. special baffle design to eliminate hot spotstion is to blanket the expansion tank vapor 3. “Systems Design Data.” Pub. #7239193ver. C, can be used.space with an inert gas (for example, nitro- Solutia Inc., 1999. Two basic configurations for electricalgen, CO2, or natural gas). When using a 4. “System Design and Maintenance.” Pub. #TBS heaters are available: container design and 10-25 (E), Solutia Inc., 1998.nitrogen blanket, moisture should be driven tubular design. 5. “Liquid Phase Design Guide.” Pub.off from the fluid before the gas pressure is • n the container design, one or more elec- I #7239128C, Solutia Inc., 1999.set. If this is not practical, air contact can trical heating elements are inserted into abe minimized by a cold seal trap arrange- container through which fluid flows. Acknowledgmentment. Low boilers and moisture can collect • n the tubular design, the heating elements Iin the cold seal trap, so the fluid in the trap Material for this “Facts at Your Fingertips” was are inserted longitudinally into tubes supplied by Solutia Inc.should be discarded periodically. through which the fluid flows.CONTROLS The tubular design is preferred for the heat- NOTICE: Although these recommendations are ing of organic fluids. If the container design believed to be correct, Solutia Inc. makes noInstall heater controls to regulate the firing is to be used, due to the unpredictable representations or warranties as to the complete-mechanism in direct proportion to the flow conditions around the elements, heat ness or accuracy thereof. Nothing containedrequired output. These controls should flux should be limited to 1–2 W/cm2. For herein is to be construed as a recommendation to use any product, process, equipment orincrease or decrease the heat input to all heater types, the maximum heat flux at formulation in conflict with any patent, and So-maintain the heat transfer fluid at the oper- the surface of the heat source and the fluid lutia Inc. makes no representation or warranty,ating temperature required by the energy velocity over it should be in proper balance express or implied, that the use thereof will notdemand. Small units may be operated to avoid excessive film temperature. Careful infringe any patent. Facts at Your Fingertips Sponsored by
    • Circle 05 on p. 62 or go to adlinks.che.com/23018-05
    • Barben Analyzer Technology Show PreviewT he Instrument Society of America (ISA) 2009 exhibitor show Expo 2009 will be held Oc-tober 6–8 at the Reliant Centerin Houston. Over 300 exhibi-tors are expected to displayautomation-and-control tech-nology products and services.The show is organized intosix different tracks, in-cluding categories forsafety, process auto- Martelmation and control, Electronicsas well as a newsection on energyand the environ-ment. In addition to exhibitors’ booths,the anticipated 11,000–12,000 attendeeswill be able to listen to daily keynote ad-dresses and a newly added program high-lighting industrial security. Participantsalso will have an opportunity to sit in onthe ISA Industry Standards Forum orattend several exhibitor educational pro-grams. In addition, a larger-than-usualnumber of co-locating meetings are sched- AMETEK Process Instrumentsuled to coincide with the Expo. Additionalinformation about the show can be found Kepcoat www.isa.org. Expo 2009 attendees are encour- A new gage with data logging in several models for inline, hot-tapaged to visit Chemical Engineering at feature is introduced or quick-change fittings and can beBooth 1604. Examples of technology A data-logging feature is now avail- used for process measurements atslated for exhibit at the Expo include able for the BetaGauge PI digital temperatures up to 140°C and pres-the following new products. pressure-test gages (photo), and can sures exceeding 3,000 psi. Booth 2735 be used with a new software applica- — Barben Analyzer Technology LLC,These power supplies are opti- tion. BetaLOG can collect pressure Carson City, Nev.mized for driving inductive loads data on multiple BetaGauge PIs and www.BAT4ph.comThese 200- and 400-W bipolar-oper- can accommodate varying time inter-ational power supplies (photo) are vals and lengths of data logging runs. Measure water and CO2 to lowdesigned for stable operation in cur- Four different types of data capture ppm range with this gas analyzerrent or current-limit mode to electric allow users to log either all data or A new gas analyzer using diode-laserinductance loads of up to 1 Henry. The only points of interest. Booth 2316 — absorption spectroscopy cost-effec-models are suitable for applications Martel Electronics Corp., Derry, N.H. tively measures water vapor and car-such as motor testing, magnetic com- www.martelcorp.com bon dioxide in natural gas and hydro-ponent testing, industrial applications carbon streams. The model 5100-NCMwith inductive loads, driving CRT This oxidation and reduction po- (photo) is tunable and has a limit ofcoils, cryogenic applications and pow- tential sensor is built to last detection in the low ppm range. Theering correcting magnets for particle A newly released oxidation-reduction laser-based analyzer features com-accelerators. Booth 2610 — Kepco Inc., sensor is built with a patented tech- pact, fully enclosed optics and sampleFlushing, N.Y. nology, known as axial ion path, to conditioning. Booth 1907 — Ametekwww.kepcopower.com allow stability, long life and reliabil- Process Instruments, Pittsburgh, Pa. ity. The sensor (photo) is available www.ametekpi.comNote: For more information, circle the 3-digit number ChemiCal engineering www.Che.Com September 2009 32D-1on p. 62, or use the website designation.
    • Show PreviewIndustrial electronics firm universal isolator. Booth 1949 —offers a host of new products Weidmuller Group, Richmond, Va.This company is trotting out a host of www.weidmuller.comnew products at the ISA show. Com-pany offerings include pre-assembled Customers can configure thesespecific interface cables, new indus- valves using online tooltrial Ethernet routers (photo), indus- The 8262/8263 Series solenoid valvestrial power supplies, a new line of are available with a Web-based toola.c. DIN-rail receptacles, and a new that customers can use to rapidly build Weidmuller a valve to meet specific requirements before ordering. The two-way valves have higher pressure ratings and can be used to control the flow of air, water and light oils in industrial-, agricul- tural- and food-products-machinery applications. The valves are available in brass and stainless steel, and come in three pipe sizes, from 1/8 in. to 3/8 in. Booth 1743 — ASCO Valve Inc., Florham Park, N.J., www.ascovalve.com This fluid-level transmitter has a simple design and installs easily The digital E3 Modulevel detects liquid level changes using a simple buoyancy principle. Features of the transmitter include a simple linkage between the level-sensing element and the output electronics, as well as a vertical construction to allow low product weight and easier installa- tion. The transmitter is available in multiple configurations and pressure ratings for use in a variety of process applications. Booth 2133 — Magnet- rol International, Downers Grove, Ill. www.magnetrol.com These shielded Ethernet switches can reduce wiring costs The ToughNet M12 Series of Ethernet switches are designed for installation directly on electronic devices at field sites without an enclosure, which re- duces wiring costs. The switches can be used for applications where elec- tronics devices must withstand harsh conditions, such as vibrations, voltage variations and electromagnetic inter- Circle 30 on p. 62 or go to adlinks.che.com/23018-3032D-2 ChemiCal engineering www.Che.Com September 2009
    • Sealevel Systems Universal Monitorsference. The switches operate within a tain no moving parts and so avoid This gas-sample probe is coupledtemperature range of –40°C to 75°C. the costs of replacing paddlewheels. with an ammonia converterBooth 2501 — Moxa Americas Inc., P420 Series plastic flowmeters (photo) The newly introduced model 270/NH3Brea, Calif. are designed for cost-effectiveness in Gas Sample Probe and Ammonia Con-www.moxa.com processing water, brine and corrosive verter (photo, p. 32D-4) is designed to fluids in water treatment, chemical provide users with both a convertedPlastic flowmeters that avoid and desalination applications. PVC and an un-converted sample stream.paddlewheel replacement cost and CPVC types are available in six This ability provides the means toThese polyvinyl chloride (PVC) and pipe diameters for flowrates from 6 to measure ammonia slip normally foundchlorinated PVC (CPVC) flowrate 200 gal/min. Booth 2504 — Universal at the exit of a selective catalytic re-transmitters are offered at the same Monitors Inc., Hazel Park, Mich. duction (SCR) process, using the “Dualprice as paddlewheel meters, but con- www.flowmeters.com NOx Differential Method.” The sample Sulzer SMXLTM and SMRTM Heat exchangers for viscous and temperature sensitive media MOVING AHEAD CT.36e Sulzer Chemtech www.sulzerchemtech.com Circle 31 on p. 62 or go to adlinks.che.com/23018-31 Circle 32 on p. 62 or go to adlinks.che.com/23018-32 ChemiCal engineering www.Che.Com September 2009 32D-3
    • Show Previewprobe and ammonia converter easy to install and re-are configured as one unit, quires minimal main-providing filtration and con- tenance. It requires aversion directly at the source smaller straight pipeof measurement. The model run than many otherincludes filter purging and a flowmeters — 1–3 pipecalibration gas inlet port for diameters upstream of Universal AnalyzersEPA (Environmental Pro- the flowmeter and 0–1tection Agency) compliance. downstream. BoothBooth 2735 — Universal Ana- 2434 — McCrometerlyzers Inc., Carson City, Nev. can be used as standalone software or Inc., Hernet, Calif.www.universalanalyzers.com be integrated with other company ap- www.mccrometer.com plications. Booth 2649 — Aveva GroupPlant instrumentation software is PLC, Houston This embedded computer offersfor contractors and operators www.aveva.com input and output flexibilityNewly introduced plant instrumen- The Relio R9 embedded computertation software aids in specifying, This flowmeter delivers high (photo, p. 32D-3) is designed to maxi-designing and maintaining plant in- accuracy in small lines mize I/O flexibility. The reduced in-strumentation and control systems. Designed for liquid or gas line sizes struction set computer (RISC) is ratedAVEVA Instrumentation represents from one to six inches, the Wafer-Cone for a wide temperature range and has aan addition to this company’s soft- flowmeter can achieve accuracies of compact housing that can be mountedware portfolio and is designed for both ±1.0%. The flowmeter can be used to in many locations. Booth 2437 — Sea-plant EPC (engineering, procurement measure natural gas flow from well- level Systems Inc., Liberty, S.C.and construction) contractors and heads, as well as in small process lines, www.sealevel.com ■plant owner-operators. The product burners or cooling systems. The unit is Scott Jenkins Circle 33 on p. 62 or go to adlinks.che.com/23018-3332D-4 ChemiCal engineering www.Che.Com September 2009
    • *e. mission. one of the four members of the e.q.p.e.c. (enemies of quality,production, environment and costs). wreaks havoc on the environment. Jamesbury Emission-Pak® valves keep your emissions under control Many process streams encourage fugitive losses. Metso Automation’s Emission-Pak provides a quick, easy way of assuring compliance with emissions standards. Mounted on Jamesbury® valves, Emission-Pak combines a PTFE/graphite body seal and gasket, which maintains a leak-free joint at the valve bonnet, with a double-packed, live-loaded V-ring steam seal mechanism that maintains a constant packing force without over-compression. Emission-Pak is available in a wide range of corrosion resistant trim materials, and is suitable for use in extreme pressure and temperature situations. www.metso.com/automation Circle 34 on p. 62 or go to adlinks.che.com/23018-34
    • Hoerbiger Kompressortechnik Holding Coriolis meters for EM-Technik low-flow applications The Micro Motion Elite Corio- lis meter range has been expanded for low-flow ap- plications (photo). Avail- able in two sizes (2- and 4-mm nominal dia.), the new meters deliver flowrates of Emerson Process 2 to 330 kg/h with accuracies Management of ±0.05% (liquid flow), ±0.35% (gas flow), and ±0.0000 g/mL (liquid density). Wetted parts are of 316L stainless steel and the sensor enclosure is available with polished-316L external sur- face and rounded corners. For corrosive and high-pres- sure applications, the meters are also available in nickel alloy construction and are rated to 413 bar. — Emerson Process Management, Baar, Switzerland www.emersonprocess.eu An optimum valve for Omega Engineering reciprocating pumps The CL pump valve (photo) for recip- R, S, B, C or N calibra- rocating pumps combines the two key tion connector. When factors for cutting operating costs into activated, the connector one valve: optimum performance and will transmit readings efficient service. The CL pump valve continuously at a pre- has an optimized design and a combi- set time interval that nation of proven materials. They can was programmed by the be incorporated into any reciprocating user. Each unit mea- Buss pump and are suitable for use with sures and transmits TC input readings ers directly into the gelled PVC melt. any aqueous solution. The valve fea- and connector ambient temperatures Both the intake zones have a larger tures heavy duty, non-metallic sealing to a receiver, which are displayed on housing and screw diameter, enabling elements, springs that do not come in the PC screen in real time using free the biggest possible fillers uptake contact with the medium being han- software. — Omega Engineering, Inc., volume in the process zone. Trials on dled, and optimized flow control. — Stamford, Conn. the quantec 50EV test facility have Hoerbiger Kompressortechnik Holding www.omega.com shown that with 100 phr chalk filling, GmbH, Vienna, Austria throughputs as high as 390 kg/h are www.hoerbiger.com A kneader for high-fill, possible with consistently excellent rigid-PVC compounding compound quality. These results have This thermocouple connector The 4-flight quantec Kneader (photo) been confirmed with quantec Kneader communicates wirelessly performs rigid PVC compounding with sizes up to 110EV. — Buss AG, The MWCT Wireless Smart Thermo- up to 100 phr (parts-per-hundred rub- Pratteln, Switzerland couple Connector Series (photo) fea- ber) fillers possible. Among the Knead- www.busscorp.com tures stand-alone, battery-powered er’s new engineering features are an thermocouple (TC) connectors that extension of the process zone to 15 Save space with transmit measurement data back to a L/D (screw length-to-diameter ratio), a new size of mini ball valves mating receiver up to 90 m away. Each and the addition of a downstream The Series 6L mini ball valves are now unit is factory set as a Type J, K, T, E, vertical Inlet Screw for feeding fill- available with a nominal diameter of 32I-2 Chemical Engineering www.che.com september 2009 Note: For more information, circle the 3-digit number on p. 62, or use the website designation.14_CHE_090109_NPi.indd 2 8/27/09 10:14:06 AM
    • © 2009 Swagelok Company 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 and happier customers. at swagelok.com/moreproducts. Circle 35 on p. 62 or go to adlinks.che.com/23018-35
    • New ProductsDN 02 and female G-thread 1/16 ger Meter valve range,in. This makes them especially is suitable for use insuitable for space-saving mount- critical areas, such asing. The ball is manufactured in bioreactors pharmaceu-one piece with the PTFE stem ticals, biologics and foodcentered by sealing sleeves, and processing. The Seriesthe stem sealed with an O-ring. SCV-09 is a modulatingThe mini ball valves are used in diaphragm style valvelaboratory and analytical appli- FF-Automation Pump Engineering that meets the manu-cations and the pharmaceutical facturing standards ofindustry. — EM-Technik GmbH, Max- and calendar controls, data logging. 3A Sanitary Standards. The valvedorf, Germany ModBus interface and so on. The unit uses a patented sealing arrangementwww.em-technik.com allows many communication possibili- that avoids metal-to-metal contact, ties, including GSM, GPRS, WLAN, which could result in metal particlesMonitor processes remotely Internet, RS-485 and TETRA. Appli- being released into sensitive prod-with this station cation programs and configuration ucts, while providing a similar level ofThe new AutoLog RTU (photo) is suit- parameters can be changed remotely, control to a metal plug and seat. Theable for remote monitoring and con- without costly onsite visits. — FF-Au- valve is available in sizes 1/2, 3/4 andtrol of oil and gas pipelines, cathodic tomation Oy, Vantaa, Finland 1 in. with 316L stainless-steel body.protection, tanks, pumping stations, www.ff-automation.com It is suitable for low to medium flow-buildings, water treatment plants rates and has a maximum operatingand environmental supervision. It An aseptic valve is designed for pressure of 10 bar. — Pump Engineer-can be used for any small to medium critical areas ing Ltd., Littlehampton, U.K.I/O quantity applications. RTU has This patented, compact aseptic control www.pumpeng.co.uk ■PLC features, PID controllers, clock valve (photo) newly added to the Bad- Gerald Ondrey Harness the power of positive press. Custom reprints from Chemical Engineering could be one of the smartest marketing decisions you make. Contact The YGS Group at 717.399.1900 x100 or learn more online at www.theYGSgroup.com/reprints The YGS Group is the authorized provider of custom reprints from Chemical Engineering.Circle 36 on p. 62 or go to adlinks.che.com/23018-3632I-4 Chem Eng_Quarter Vert.indd 1 ChemiCal engineering www.Che.Com september 2009 3/10/09 3:10:03 PM
    • Circle 24 on p. 62 or go to adlinks.che.com/23018-24
    • cover story feature reportStrategies forWater Reuse Membrane technologies increase the sustainability of industrial processes by enabling large-scale water reusePeter Aerts and Flora Tong Secondly, population growth and The main technical challenge toDow Water & Process Solutions urbanization, which go hand in hand reuse this blowdown water is the un- with industrialization and an im- stable pH of the water with high salt provement of the living standard, cre- content (referred to as total dissolvedI n more and more locations, the ate a local imbalance between water solids or TDS), high hardness (high availability of fresh water re- supply and demand. This is currently concentration of Ca+2) and high alka- sources is limited and water reuse occurring in Asia and is influenc- linity (HCO3–). Sometimes blowdown is becoming increasingly impor- ing policy makers to stimulate water contains high levels of Si, SO4–2, chem-tant. For many industrial applications, reuse. Water reuse has some practical ical oxygen demand (COD) and quitethe availability of water is essentially challenges in these regions, though. often high levels of suspended solids.a “license to operate”. First, the lack of infrastructure drives The water quality varies substantially A large component of the water the popularity of modular technol- with region, since the feed source forconsumption in many chemical pro- ogy offerings; and second, the need to cooling towers is surface water.cess industries (CPI) is high- and low- achieve very stringent quality speci- In a cooling tower, the absorbedpressure boiler water. As such, reusing fications of reused water drives tech- heat is released to the atmosphere bycooling water blowdown — water dis- nology development. the evaporation of some of the cool-charged from the cooling water system Membranes are an important ing water in mechanical forced-draft— for boiler water makeup can be a technology used for water treatment, or induced-draft towers. More thanvery attractive option in water-stressed and various types of membranes are 90% of all the water used by indus-areas. Another option gaining atten- available to address different needs, try and about two-thirds of the totaltion is recycling municipal wastewater as illustrated in Figure 1. Figure 2 wastewater generated by U.S. manu-for industrial uses. In this article, the offers an illustration of the multiple facturing plants is the result of cool-technology options, advantages and layers that allow wastewater to be ing operations. The circulation ratedisadvantages of using membranes to successfully treated using mem- of cooling water in a typical 700-MWreuse water for these key industrial brane technology. coal-fired power plant with a coolingapplications are discussed. tower amounts to about 71,600 m3/h process water from (315,000 gal/min) and the circulat-the drivers for reuse cooling towers ing water requires a makeup rate ofWater reuse has several drivers. First Blowdown characteristics perhaps 5% (or 3,600 m3/h). In manyof all, the need for water reuse is re- Cooling tower blowdown water is petroleum refineries, makeup water tolated to freshwater availability, which often discharged to the sanitary sewer the cooling tower can account for updepends on the natural environment, system, however, for power plants, to 50% of the total demand for freshclimate and the industrial and urban petroleum refineries, petrochemical water. A typical large refinery process-pollution related to the use of water. and chemical plants, as well as natu- ing 40,000 metric tons (m.t.) of crudeThe affordability of water treatment ral-gas process plants, cooling tower oil per day (300,000 bbl/d) circulatescompared to the price of freshwater blowdown water is recognized as the about 80,000 m3/h of water throughis a driver for reuse in areas where best available water source to reuse its cooling tower system of which halfthe two are similar. In regions where because of the large volume that is (40,000 m3/h) needs to be replenished.freshwater is relatively inexpensive, available and the mature technology In open, recirculating cooling-waterunfortunately, water conservation and options that are proven to achieve the systems, the concentration of mineralreuse are not high priorities. right water quality. salts increases as evaporation occurs.34 ChemiCal engineering www.Che.Com September 2009
    • Membrane Filtration Spectrum Ionic range Molecular range Macro molecular range Micro particle range Macro particle range Reative size of common materials Metal ions Latex/Emulsions Endotoxins/Pyrogens Bacteria Insecticides Colloids Soluble salts Viruses Algae Dissolved organics Human hair Antibiotics Giardia Crypto Micrometers, log scale 0.0001 0.001 0.01 0.1 1.0 10 100 Approximate molecular weight, daltons 100 200 1,000 10,000 20,000 100,000 500,000 Angstrom units, log scale 1 10 100 1,000 104 105 106 2,0 3,0 5,0 8,0 20 30 50 80 20 30 500 80 00 00 00 00 2 3 5 8 0 0 0 2 3 5 8 2 3 5 8 Separation processes Reverse osmosis Microfiltration IX Nanofiltration Electrodeionization UltrafiltrationFigure 1. Membranes are used in a spectrum of filtration applications down is minimized, the concentration Brine channel ratio increases. The amount of blow- spacer Leaf width down minimization that is possible and its potential savings is guided by Product Water flow water the quality of the feedwater. Most of the scaling impurities in cooling water are alkaline, usually in the form of Ca+2, Ba+2, Sr+2 and Mg+2 Leaf associated with bicarbonate and silica. length Membranes The higher the concentration of these impurities, the higher the pH value of Permeate channel spacer the water will be. These impurities, es- Brine seal pecially calcium bicarbonate, are less soluble at higher pH values. There- Brine fore, acid (usually sulfuric) is added Feed to the circulating water to lower the Brine pH and increase the solubility of theFigure 2. This spiral-wound RO membrane actually consists of two membranes impurities so they can be removed bywith a brine channel spacer at the feed side and a permeate channel spacer at the proper blowdown of the system.permeate side, which allow the product water to move to the center of the element Corrosive salts are part of the dis- solved solids, sulfates and chlorides,When the concentration of mineral mineral salts and dissolved contami- which can be kept under corrosivesalts exceeds their solubility, fouling nants. The discharged volume needs limits by disposing of a percentage ofand scale formation on heat exchange to be replenished with fresh makeup the re-circulated water and by add-surfaces will occur. The water is cycled water. Clearly, management of cooling ing fresh water to the cooling tower.through the cooling water system nu- tower blowdown is necessary to prevent Corrosion can be minimized by themerous times before the water becomes fouling and scaling and to efficiently addition of a corrosion inhibitor thatsaturated and must be discharged out use the makeup-water resource. Water reacts with a metallic surface, or theof the system. This discharged water, consumption of cooling towers can be environment this surface is exposedwhich is called blowdown water, is con- reduced significantly by minimizing to, as a result giving the surface a cer-trolled by a conductivity sensor and blowdown in coordination with an in- tain level of protection.bleed valve in the tower basin to moni- tegrated operation and maintenance Despite the various qualities of cool-tor the upper concentration limit of the program. Obviously, when the blow- ing-tower blowdown water, it is often ChemiCal engineering www.Che.Com September 2009 35
    • Cover Storyrecycled as boiler makeup water. fulltime condensate polishingQuality needed for boilers requirements. Neither AVT norBoilers are mainly classified by low phosphate chemistry is practicalpressure (< 600 psig), medium pres- in BWR primary systems sincesure (600–2,400 psig) and high pres- condensate circulating throughsure (>2,400 psig) systems. Any water the nuclear reactor has the po-used for this application needs to be tential for induced radioactivity.pretreated or polished. The type of High pressure: As the boilercondensate polishing operation de- pressure increases beyond 2,450pends on the operating parameters. psig (169 bar), demineraliza-Low pressure: For low pressure tion of makeup water of theboilers at steam pressures below major contaminant ions, such600 psig (41 bar), boiler feedwater is as sodium and silica, becomestreated to prevent hard scale forma- mandatory to satisfy the watertion and corrosion in the boiler. Some quality requirements. Chemicaltype of chemical addition, such as treatment of the boiler or steamphosphate addition, is used together generator system shifts fromwith gross particulate filtration and phosphate treatment to the usedecarbonation. Boiler water salts are of AVT using ammonia or amineskept from the steam cycle by control to elevate pH and control corro-of the entrainment carryover and by sion in the high temperature andboiler blowdown. wet-steam areas of the steam-Medium pressure: For medium condensate loop. The optimumpressure boilers with steam pressures pH range depends on the ma-of 600 to 2,400 psig (41 to 165 bar), terials of construction; at least FIGURE 3. This is an example of a fiberglasscontrol of silica, control of corrosion, 9.3 for all-ferrous systems and reverse osmosis (RO) membrane elementand removal of particulate matter are 8.8–9.2 for systems containingrequired. Control of silica is neces- copper. For high pressure boilers, full- followed by strong-base-anion ex-sary to prevent silica from volatilizing flow condensate polishing is a critical change resins (in the OH– or Cl– form)with the steam and depositing on the operation for the removal of soluble to remove ions. This is followed down-turbine blades. Makeup feedwater de- and insoluble corrosion products, and stream with a mixed bed.mineralization with an anion bed can for the removal of contaminant ions as The main considerations for de-control the silica levels in the water a result of a condenser in-leakage. mineralization operation using ionif it cannot be controlled economi- In North America, pressurized- exchange resins are operating eco-cally with boiler blowdown. Control water-reactor (PWR) plants using nomics, quality and reliability of resinof corrosion is mainly done by add- recirculating-type steam generators performance and minimizing environ-ing phosphates or using all volatile (RSGs) have focused their secondary mental costs. The primary variables intreatment (AVT). AVT uses ammonia cycle, water-chemistry program on determining the operating economicsor other volatile amines (morpholine, the minimization of insoluble-corro- are costs associated with regeneration,monoethanolamine) to adjust water sion-product transport and sodium- waste neutralization and disposal, aspH and control corrosion in that way. to-chloride molar ratio control in the well as, resin replacement and dis-Condensate “scavenging” is often used tubesheet crevice areas of the steam posal. Field experience and laboratoryto remove corrosion products from generator. A shift to the use of organic tests show that ion-exchange resins ofcondensate returning from the tur- amines (monoethanolamine in most uniform particle size offer numerousbine. Condensate scavenging uses a cases) for pH control and procedural advantages over resins with a conven-cation-resin deep bed operated in the changes in the resin-regeneration tional Gaussian particle-size distribu-sodium or amine form to filter partic- process have been instrumental in tion. These advantages include, butulate matter and to remove all hard- achieving the desired improvements are not limited to, higher regenerationness ions. in secondary-cycle water chemistry. In efficiency, greater operating capac- While many systems in the 600 to addition to AVT chemistry, hydrazine ity, reduced leakage and better rinse2,400 psig (41 to 165 bar) pressure is added to scavenge trace amounts of characteristics. The second methodrange do not require condensate pol- dissolved oxygen and maintain reduc- uses reverse osmosis membranes atishing, there are exceptions. For ex- ing conditions. a recovery of 70–75% to remove >99%ample, nuclear-fueled boiling water of all the ions present in the water. Asreactors (BWR) have historically been Boiler-water preparation a second step downstream for further“zero solids” systems, even though the There are several main routes used to polishing to achieve low conductivityboilers used typically operate near prepare boiler water. The most known in boiler makeup water, either mixed-1,250 psi (86 bar). They have stringent method is using strong-acid-cation ex- bed ion exchange or electrodeioniza-feedwater-quality requirements and change resins (in the H+ or Na+ form) tion (EDI) is used.36 ChemiCal engineering www.Che.Com September 2009
    • Electrodeionization: Electrodeion- tenance costs. RO elements are also tration and pH adjustment prior to theization is a continuous and chemical- frequently used in double-pass RO RO elements. Iron coagulants with orfree process of removing ionized and systems to produce high purity water without polymeric flocculants (anionicionizable species from the feedwater in a simpler continuous process. and nonionic) may be used to improveusing direct current (d.c.) power. EDI the solid-liquid separation.can produce up to 18 mΩ-cm high-pu- Blowdown as boiler makeup The advantages of lime softeningrity water with high silica and boron Currently, most newly built fossil- are the high removal efficiency forrejection (micro-ohm centimeters are fuel power plants with recycle cooling hardness and alkalinity, and less scal-a unit of resistivity for pure water). systems and some existing fossil-fuel ing potential for RO membranes re-As a result, EDI can replace conven- power plants already employ waste- sulting in a lower cleaning frequency,tional mixed-bed ion exchange, and water reuse. There are mainly three which makes this technique suitableeliminate the need to store and handle types of reuse systems: chemical soft- for large-scale wastewater reuse. Thehazardous chemicals used for resin ening, a high-efficiency reverse osmo- disadvantages are the large footprint,regeneration and associated waste sis, and ultrafiltration combined with the fact that it is labor intensive andneutralization requirements. Direct reverse osmosis. the need of pH adjustment and mediacurrent is applied across the cells. The Chemical softening: Lime softening filters prior to RO trains. Further po-d.c. electrical field splits a small per- can be used to remove carbonate hard- tential risks include the residual hard-centage of water molecules (H2O) into ness by adding hydrated lime: ness if only lime is applied (which willhydrogen (H+) and hydroxyl (OH–) affect scaling on the RO membranes)ions. The H+ and OH– ions attach Ca(HCO3)2 + Ca(OH)2 → and the possibility to clog subsequentthemselves to the cation and anion 2 CaCO3 + 2 H2O (1) filters due to slow reaction.resin sites, continuously regenerat- High efficiency RO: Increased RO- Mg(HCO3)2 + 2 Ca(OH)2 → Mg(OH)2ing the resins. Since hydrogen ions process efficiency is obtained by combin- + 2 CaCO3 + 2H2O (2)have a positive charge and hydroxyl ing several industry-proven treatmentions have a negative charge, each will As a result calcium, barium, stron- steps into a single process that has themigrate through its respective resin, tium, and organic substances are ability to treat difficult water at high re-then through its respective permeable reduced significantly. Colloids and coveries and increased flux rates.membrane and into the concentrate suspended solids can be removed by In the first step, the feedwater un-chamber due to ionic attraction to the adding coagulants or flocculants just dergoes a weak-acid cation (WAC),cathode or anode. Cation membranes before lime dosing. partial softening before a strong acidare permeable only to cations and will The noncarbonate calcium hardness cation (SAC) completes the soften-not allow anions or water to pass, and can be further reduced by adding so- ing, followed by chemical injectionanion membranes are permeable only dium carbonate or “soda ash”: to raise the pH. When hydrogen ionsto anions and will not allow cations or are exchanged with hardness ions, CaCl2 + Na2CO3 →water to pass. The H+ and OH– ions a balanced hardness-to-alkalinity 2 NaCl + CaCO3 (3)collect in the concentrate (C) chamber ratio is achieved during the process,to yield water. Contaminant ions, dis- The lime soda-ash process can also be improving WAC efficiency. Hydrogensolved in the feedwater, attach to their used to reduce the silica concentra- ions also reduce the pH, causing therespective ion exchange resin, displac- tion. When sodium aluminate and fer- water stream to be acidic and convert-ing H+ and OH– ions. Once within the ric chloride are added, the precipitate ing much of the alkalinity to carbonicresin bed, the ions join in the migra- will include calcium carbonate and a acid and CO2. Adding more acid attion of other ions and permeate the complex with silicic acid, aluminum this stage converts remaining alka-membrane into the C chambers. The oxide, and iron. After the clarifica- linity to CO2. Degasification (such ascontaminant ions are trapped in the tion step, an RO operation is carried removal of carbon dioxide and otherC chamber and are recirculated and out. This requires a pH adjustment gases) follows. In this stage, the pHbled out of the system. and media filters upfront in order to can be increased to 10.5; this will raise In many industrial systems, re- protect the RO membranes. A con- the solubility of silicates and destroyverse osmosis (RO) elements (Figure ventional RO system can tolerate 150 any biological components. Next, the3) serve as pretreatment for ion ex- mg/L silica in feedwater. feedwater enters the RO membranes.change resin beds. When installed be- With the hot lime-silicic-acid re- These membranes must be of suffi-fore ion exchange beds, RO elements moval process at 60–70°C, silica can be cient quality and robustness to with-reduce demineralizer operating costs reduced to 1 mg/L by adding a mixture stand the high pH operation (Figuredramatically. For example, pretreat- of lime and porous magnesium oxide. 4). Under these conditions, there is lit-ing water for boiler makeup with RO This process requires a reactor with tle or no scaling or fouling. This allowselements removes silica, dissolved a high concentration of precipitated operation at very high water recoverysolids and total organic carbon (TOC). particles serving as crystallization nu- of 85–95%, relative to conventionalThis extends the life of ion exchange clei. This is usually achieved by upflow RO at about 75%.resins and lowers chemical regenera- solids-contact clarifiers. The effluent The advantages of this more-effi-tion usage, waste handling and main- from this process requires media fil- cient RO process include total hard- ChemiCal engineering www.Che.Com September 2009 37
    • Cover Storyness removal (more than 99.5%) and flow distribution through thesubstantial silica removal combined bore of hollow fiber comparedwith high water recovery without the to the outside-in configura-risk of scaling. This operation avoids tions. UF systems are typicallybiofouling and organic fouling because operated in crossflow mode atbacteria, viruses, spores, and endotox- high recovery and flux rates.ins are either lysed or saponified at Cleaning is done frequentlythese operating conditions. Removal using backwashing, and air-of scaling constituents in the pretreat- scouring techniques are oftenment steps eliminates the need for used to reduce fouling. Thescale inhibitors in the high efficiency last step involves a classicalRO. The combination of WAC and SAC RO setup that operates at aincreases the regeneration efficiency water recovery of 70–75%.for resin beds. The disadvantages of The advantages of the com-this technology are the higher cost of bined UF and RO technologiesregeneration chemicals and license are highly efficient suspended-fees together with the higher complex- solids removal and the abilityity of the system. to automate and expand the FIGURE 4. Quality control is applied duringCoagulation followed by UF and membrane filtration units. membrane fabrication. Here a membrane sheet isRO: A third technology is based on The disadvantages include a being rolled on the manufacturing floorcoagulation-flocculation and clarifi- limited number of water typescation followed by membrane tech- that are applicable because of the lack tions, which are interrelated with theniques. This process setup is designed of a removal step for hardness-alka- cleaning frequency and membraneto treat raw waters containing high linity in pretreatment. Classical ways replacement rates.concentrations of suspended matter to prevent RO scaling by antiscalant- Reverse osmosis products with aresulting in a high silt-density index pH adjustment use a large amount of higher fouling resistance for organic(SDI). Classical coagulation-floccula- chemicals. The recovery of RO units is fouling, biofouling and scaling are nat-tion techniques are used where hy- also relatively low because of the lack urally preferred in this cooling towerdroxide flocs grow and settle in spe- of hardness-alkalinity removal. blowdown application. Higher pHcifically designed reaction chambers. Selection of RO membranes is tolerance will allow longer operationThe hydroxide sludge is removed, highly dependent on the permeate- life. Large systems require low energyand the supernatant water is further water quality requirements. Higher- membrane with higher salt rejectiontreated by media filtration. For the rejection, RO membranes are re- and potentially could benefit from acoagulation-flocculation process, ei- quired and dependent on the type of 16-in. element where the availabilityther a solids-contact type clarifier or a boiler, the need for TDS removal (in of space is a constraint.compact coagulation-flocculation reac- case of ion exchange) and the cycles It is expected that UF products withtor may be used. of concentration. Fouling resistant a smaller pore size for lower molec- In a second operation, ultrafiltration membranes can be chosen if the ular-weight cut off (MWCO) will be(UF) membranes remove virtually all makeup water has a high tendency able to remove TOC more effectively.suspended matter and also dissolved for biofouling or microbial growth. A higher flux will reduce the overallorganic compounds, depending on The typical recovery of an RO sys- operating and capital costs. Further-their molecular mass and on the mo- tem is equal to or less than 70–75% more, easy cleaning and improvedlecular mass cut-off of the membrane. (except for the more efficient process cleaning protocols of membranes willHence, an SDI <1 can be achieved mentioned earlier). And most plants establish UF as a premier solution inwith a well-designed and properly will experience a significant increase the water reuse industry.maintained UF system. Hollow fibers in cleaning frequency when the sys-are the most commonly used UF mem- tem recovery is >80%. Undoubtedly, MuniCipal waterbrane configuration (cover image), a high recovery will cause a higher aS a SourCewhich can be operated in two different concentration factor, which increases Due to increasing water stress andways: feed flow can be from outside-in the operational risk. In the case of the resulting competition for high qualityor inside-out. more efficient RO process described, fresh-water resources, the use of con- For outside-in configurations, there the recovery can be as high as 90% ventional water sources for industrialis more flexibility in the amount of but robust RO membranes need to cooling water and boiler water makeupfeed to flow around the hollow fibers, be chosen to withstand the long ex- may be limited or restricted. However,whereas for inside-out configurations posure to high pH. Overall, one can reclaimed water is a constant waterthe pressure drop through the inner say that the maximum system recov- source with little competition to ac-volume of the hollow fibers is a limi- ery and sustainable flux will depend cess this resource. As a result, the usetation. Inside-out configurations, how- on the actual water conditions, the of treated wastewater from municipalever, provide a much-more uniform pretreatment and operating condi- sewage-treatment plants can be a valu-38 ChemiCal engineering www.Che.Com September 2009
    • able diversification strategy for indus- technology. Today, this reuse scheme by ion exchange or electrodeionizationtrial water supply, including cooling is present on all continents. Gener- for the makeup of boiler feedwater;and boiler water. Furthermore, the cost ally, three main membrane technology and 3) The use of membrane bioreac-of fresh water and wastewater, in addi- solutions for the treatment of tertiary tors (MBR) as a direct pretreatment oftion to scarcity of fresh water, is driving effluent for industrial water use can reverse osmosis is expected to be usedthe end user to reuse and recycle their be distinguished: 1) The use of ultra- more frequently in the future as a lowwater resources. Additional benefits of filtration pretreatment of the effluent footprint solution for onsite wastewa-the use of municipal wastewater are before RO for use in cooling water; 2) ter reclamation. ■that the treated effluent from highly Further polishing of the RO effluent Edited by Dorothy Lozowskiurbanized areas is more stable in qual-ity than river water and therefore, less Authorsmaintenance and process control are Peter E.M. Aerts is senior Flora (Xiaolan) Tong is research specialist at Dow a technical service and de-required. Lastly, permits and adminis- Water & Process Solutions velopment engineer at Dowtrative burdens are often less for reuse and global application devel- Water & Process Solutions opment leader for wastewater (DW&PS R&D, No. 936,than for conventional water resources. and water reuse applications Zhangheng Road, Zhangji- (DW&PS R&D, 1691 N Swede ang Hi-Tech Park, Shang-In addition, public acceptance of this Road, Larkin Laboratory hai, 201203, P.R.C. Phone:reuse scheme is high. 120-3, Midland, MI 48674; +86-21-38511671; Fax: Phone: 989-636-5487; Fax: +86-21-58954597; Email: Municipal water reclamation for 989-638-9944; Email: paerts@ ftong@dow.com. She has anindustrial water use (mainly cooling dow.com). He holds an M.S. M.S. in materials science in chemical and biochemical engineering and and engineering from the Dept. of Chemicalwater use) has a long track record. The a Ph.D. in applied biological sciences from KU Engineering, Tsinghua University (China).first installation was introduced in the Leuven (Belgium). Aerts has a profound un- Tong provides technical service to regional derstanding of membrane technologies through customers and is engaged in application devel-1940s, while most of the installations his research and application development of opment for wastewater and water reuse in the ultrafiltration, MBR, nanofiltration and reverse Asia Pacific region.began operating in the 1990s in North osmosis in wastewater and water reuse applica-America and Europe due to increased tions. He has also been involved in membrane development, filtration products developmentwater stress and large-scale use of RO and application research. Circle 25 on p. 62 or go to adlinks.che.com/23018-25 ChemiCal engineering www.Che.Com September 2009 39
    • Feature ReportMultivariable Predictive Control:The Scope is WiderThan You ThinkRafael Lopes,Robert K. Jonas and With increasingly tighter integration betweenAlexandre DalmaxHoneywell International process units and more aggressive optimizationM ore and more, the chemical goals, this technique is gaining attention throughout process industries (CPI) are seeking out the benefits of the CPI as an alternative to PID control flexible production and max-imizing energy and material recovery.Process units are becoming tightly and sudden disturbances, varying process delays, nonlinear processes,integrated, and the failure of one unit transport delays, the anomalies of and noisy process signals. This leadscan seriously degrade overall produc- sensors (such as ore slurry densities to suboptimal control and increasedtivity. Meanwhile, with the influx of and pulp consistencies), non-linear tuning effortlarger and larger scale operations, temperature behaviors, and many of • ID is not as robust as alternatives, Peven small changes in productivity the unique issues associated with a often delivering higher processcan seriously affect profitability. given process. variability While the petrochemical industries In order to successfully implement • ID tuning is not easy to handle. Ef- Phave been successful in using multi- multivariable control, it is necessary fective tuning requires experience,variable predictive control (MPC) to to have a good methodology such as extensive training, and an invest-manage such complexities, the rest of the following: ment in tuning softwarethe CPI leaves room for much wider 1. Assess • ID transfers process-signal noise Pand more frequent MPC deployment 2. Define directly to its controller output. Thisand the higher productivity and lower 3. Execute accelerates valve wear and increasescosts that accompany it. These sec- 4. Deliver energy usagetors have been slow to adopt MPC, but 5. Sustain These weaknesses add up over time,that trend appears to be changing. The The bottom line is that the selection with the net impact being that PIDreliability and amount of automation process must strive for MPC software use may actually increase processin industries, such as pulp and paper, that is robust and can therefore sus- variability, decrease production andand mining and metals have improved. tain more time on-control and there- product quality, and ultimately in-MPC has been successfully imple- fore generate more benefits. crease operating and maintenancemented in ore grinding, smelting, and costs. Figure 1 shows an example ofin all parts of alumina refining. In the Problems with the status quo poor PID behavior.pulp industry, MPC also is now a real- While proportional–integral–deriva- This case represents a heat dutyity and has been implemented success- tive (PID) controllers are applicable to control (QC) loop, cascaded with afully in lime kilns and bleach plants. many control problems, they can per- steam flow loop, which is connected MPC requirements are to deeply form poorly in some applications. directly to a control valve. Any QCstudy and understand the process, use PID controllers, when used alone, variation leads to a bottom level vari-operators’ and engineers’ experience, can give poor performance when the ation. This bottom level swing leadsfind the key variables and solve the PID loop gains must be reduced so to a column-bottom temperaturecontrol problem. But, the main require- that the control system does not over- variation. The bottom temperaturements that are consistent across the shoot, oscillate or “hunt” about the variation covaries with the exchangerCPI for a good multivariable control control setpoint value. Another prob- outlet temperature. Meanwhile, theimplementation are an MPC control- lem faced with PID controllers is that exchanger outlet temperature leads toler and model that are robust enough they are linear. In summary, PID limi- a QC variation. Also, this control loopto handle changing plant conditions. tations are: is sending two different signals for theAn MPC must be able to handle large • ID controls have difficulty handling P same valve (QC level correction and40 ChemiCal engineering www.Che.Com September 2009
    • ExpErt SyStEmS and mpC An expert system is essentially software that provides a compilation of equa- tions, rules of thumb, and do’s and don’ts — all based on the knowledge and skills that an experienced engineer would apply to solving a problem. On the other hand, MPC is based on empirical modeling, predicting the pro- cess behavior in the future. Thus, MPCFigure 1. PID controllers can actually increase process variability, especially with has much higher capabilities than anmultiple input, single output situations expert system. While MPC is certainly different than PID and expert systems (see box for more), a common perception is that MPC is more difficult to apply. Actually, the reverse is true. The com- plexity of application is internal to the software, thus the people imple- menting MPC need only to defineFigure 2. The right half of this graph shows reduced variability after the imple- models and then configure desiredmentation of MPC in an ASU and an oxygen purity within the 99.5% target operation targets. Model definition has been made much easier through use of automated modeling software, process stepper applications, and on- line and on-control modeling software. In expert rules, fuzzy logic and com- plex PID strategies, the implementer needs to be a process and control ex- pert, and needs to carefully design a system. The expert needs to consider how to deliver the majority of benefits given the limitations of these control technologies. For example, expert sys- tem and complex PID strategies have difficulties in the following areas: • ime-based dynamics require some T skill and effort to implement, and thus are often eliminated or simpli- fied to reduce cost and effortFigure 3. After the implementation of MPC (red lines) the vacuum distillation pro-cess experienced much less variability and a lower fraction of lights in heavies • nteractions between controls and I process require some skill and effortflow variation correction), which gen- models, in order to take more timely to implement, and thus are oftenerates a high frequency upset. This is preventive and corrective actions to eliminated or simplified to reducean example of how the PID would deal ensure better regulation and plant cost and effortpoorly with a MISO (multiple input, stability. These models consider the in- • esign, building, testing, commis- Dsingle output) situation. teractions between the key plant vari- sioning, and maintaining a com- Because of the widespread use of PID ables and, therefore, MPC is consid- plex custom application, and the— and the technology’s inherent weak- ered a multiple input, multiple output resulting complexity (cost) versusnesses — regulatory (or direct) process (MIMO) technology. In addition, the benefitscontrols remain one of the last frontiers predictive capability of model-based • oor operator acceptance and utili- Pfor pushing performance further. MPC further reduces plant variability zation due to elimination and sim- One of the effective and leading ad- and allows plants to operate closer to plification of dynamics and interac-vanced control technologies is MPC. the real plant limits, enabling more tions. Simply stated, the advancedThe philosophy of MPC is to predict productivity and cost reductions than controls do not respond to many sit-the plant behavior, based on heuristic any other advanced control technology. uations. It is not uncommon to have ChemiCal engineering www.Che.Com September 2009 41
    • Feature Report less than 50% control utilizationMPC examples in the CPIAir separation units comparedwith MPC for common petrochemi-cal vacuum distillation towers. Inthis example, a petroleum refinery’svacuum distillation column will becompared with a steel mill’s air sepa-ration unit (ASU). Vacuum distillation of petroleumhydrocarbons is a well-known, refiningprocess commonly used to minimizethermal cracking of heavier fractionsof crude oil and obtain lighter desiredproducts. Distilling these heavier ma-terials under lower pressure decreasesthe boiling temperature of the varioushydrocarbon fractions in the feed and Figure 4. This example shows the reduced variability that MPC achieved in an alu- mina digestion plant. Similar benefits can be expected in cellulose digestiontherefore minimizes thermal crack-ing of these fractions. It is important cess variations, however, they are typi- industry. The second example will de-in such systems to reduce pressure as cally detuned in order to avoid large os- scribe the MPC similarities between a much as possible to improve vapor- cillations in the plant conditions, which cellulose pulp, continuous digestionization. Vaporization is enhanced by can lead to variations in flowrate and unit and an alumina digestion unit.various methods, such as the addition purity of the ASU plant products. For cellulose production, wood andof steam at the furnace inlet and at In both vacuum distillation and air caustic soda are heated and then fedthe bottom of the vacuum distillation separation, the main challenges are as into the continuous digester. The woodcolumn. Vacuum is created and main- follows: increase throughput; reduce can be impregnated with white liquortained using cooling water condens- operator intervention; less downtime in countercurrent flow, while black li-ers and steam driven ejectors. In a or fewer loss-producing events; the quor is added to the wood material atconventional system of this type, the ability to change production rates very the inlet to the impregnation vessel.first stage condenses the steam and quickly, without upsetting the plant The object of this procedure is primar-compresses non-compressible gases, and the key purities. ily to increase the concentration of ac-while the second and third stages re- Common manipulated variables for tive chemicals in the digesting liquormove the non-condensable gases from both cases would be as follows: by withdrawing a certain amountthe condensers. The vacuum produced • team consumption S of impregnation liquid in which theis limited to the vapor pressure of • eedrate F content of active chemicals has beenthe water used in the condensers. If • op pressure control T substantially consumed. The liquid-to-colder water is supplied to condensers, Common controlled variables for both wood ratio in the digester is therebya lower absolute pressure can be ob- cases would be as follows: lowered, thus giving a high concentra-tained in the vacuum tower. • team valve openings S tion of active chemicals, which results Cryogenic ASUs have been used to • ain product qualities (for instance, M in rapid digestion. Then, the celluloseproduce oxygen, nitrogen, argon and oxygen purity in air for ASU, lights is withdrawn from the pulp, going toother gases, as desired. An ASU gen- in heavies in petrochemical vacuum the purification processes.erates gases by refrigerating air and distillation column) For the alumina digestion unit, thedistilling it, so energy is the primary • ressure differential through the P digesters provide a means of: mixingproduction cost of an ASU. ASUs may column the heated spent liquor and bauxitebe integrated into a network, with a • olumn bottom level C slurry to arrive at a target digestioncentrally managed pipeline network Figure 2 illustrates the oxygen purity temperature; maintaining that tem-for transporting the output gases to before and after MPC, while Figure 3 perature for a lapse of time sufficientcustomers, or can be stand-alone units shows the lights in heavy specification to dissolve the alumina from the baux-without a network connection. Tradi- before and after MPC. Both figures ite; and reducing the silica dissolvedtional regulatory controllers, such as show a clear reduction in variability by the desilication reaction to a toler-PID controllers, can be used to control and a clear shift toward the desired able level.various flowrates in an ASU. For ex- setpoint. For example, the oxygen-pu- The digestion of bauxite to extractample, PID controllers have been used rity target was 99.5%, and the speci- alumina is carried out in a train con-to control the flowrate of the rich liquid fication for total lights in heavies is sisting of vertical digesters arrangedinto the low pressure column in ASUs. lower than 0.8% in series. The digester train has onePID controllers work well under steady MPC for digestion units in alu- set of small digesters, followed by a setstate conditions, with only minor pro- mina refinery and pulp-and-paper of large vertical digesters. The small42 ChemiCal engineering www.Che.Com September 2009
    • But, if the software is sufficiently ro- bust, the effects of a model mismatch will be minimized. Some technologies consider this robustness in their algo- rithms and the controller behavior is smoother. ■ Edited by Rebekkah Marshall Authors Rafael Lopes Duarte Bar- ros is the advanced solutions leader at the Honeywell do Brasil Center of Excellence (Av. Tamboré, 576, Tamboré 06460-000, Barueri, SP, Bra- zil; Phone: +55-11-3475-1900; Fax: +55-11-3475-1950; Email: rafael.lopes@honeywell.com). He has six years experience as a chemical and automationFigure 5. Most data gathered in a plant test such as this one are not suitable on engineer, with emphasis ontheir own for building an MPC model. In most CPI sectors robust software is needed process engineering. His main areas of specialty are multivariable process control, realtime opti- mization, manufacturing execution systems and digesters, which are equipped with ag- Robustness is key. Even though MPC all the solutions related to process optimizationitators, provide for dissolution of alu- can be implemented in areas different for the chemical process industries (including specialty chemicals, petrochemicals, pulp and mina and the large digesters, without than traditional petrochemical appli- paper, metals and mining). He has a B.S.Ch.E. agitators, provide additional holding cations, the software has to be much from the Instituto Militar de Engenharia (Mili- tary Institute of Engineering), in Brazil and is time to ensure liquor desilication. more robust. This is because, gener- working on a Ph.D. in Chemical Engineering Some of the common manipulated ally, the data gathered for the control- from the University of São Paulo. Barros has more than 10 published papers in international variables in either the cellulose or alu- ler modeling are not very good. For congresses and technical magazines.mina case are as follows: example, in an alumina refinery, the Robert (Bob) K. Jonas has worked in the area of• team flow to liquor heating (before S feed is a slurry and not a liquid (as in advanced controls and solu- it gets into the digesters) petrochemical plants). Meanwhile, the tions for over 18 years with Honeywell (Honeywell In-• iquor and pulp (wood or bauxite) L number of operational procedures is ternational, 2500 W. Union flows larger than in a petrochemical plant. Hills Dr., Phoenix, AZ 85053; Phone: 602-313-5541; Email: • ressure controls P Figure 5 shows an example of data bob.jonas@honeywell.com). The majority of his experience Some of the common controlled vari- gathered to make a modeling work. has been with installing andables are as follows: Less than half of the steps shown here consulting regarding model predictive controls (MPC). He has been a consul-• atio of product to total caustic R can be used to model the plant. In this tant in the development of two MPC products by • team valves S particular data set, there are gaps in Honeywell. In addition, Bob has developed and installed other advanced control strategies in-• igestion residence times D the data, plant bumps and non-re- cluding Expert Rules, Fuzzy Logic, and complex-• eed temperatures F sponsive loops. If the control engineer cascaded regulatory schemes. Bob has spent seven years in the mining and metals industry Figure 4 shows a real gain example uses this data to build the controller in various roles relating to advanced control: advanced controls project leader, performing ad-in an alumina digestion plant, which models, there will be some model mis- vanced controls studies and consulting, as wellis similar (from a process control per- matches (gains smaller than reality, as developing business through benefit-based analysis of advanced controls. In addition, Bob spective) to a cellulose digestion unit. different dynamic responses than re- has applied or consulted on advanced controlsDespite obvious similarities, many ality, wrong times to steady state and for power generation, pulping, and petrochemi- cal industries. He has a B.S. in electrical engi-column distillation and cellulose di- so on). neering from Colorado State University, special-gesters utilize MPC, while many ASUs If a controller with these model izing in control systems. Alexandre Dalmax is aand alumina digesters still only use mismatches is implemented, sources sales manager for Honeywell’s expert systems. of controller inefficiency will exist. metal and mining verticals in Brazil (Honeywell do Brasil, Rua Pernambuco, 353/1006, Funcionários 30151-150, Belo References and Best Practices for Automatic Process Con- trol, 2006. http://www.controlguru.com/pages/ Horizonte, MG, Brazil; Phone: 1. Ha, Bao, Cryogenic distillation system for table.html (accessed February 25, 2008). +55-31-3261-4321; Fax: air separation. U.S. Patent 6,196,024, June +55-31-3261-4841; Email: al- 2001. 6. Electronic Design: What’s All This P-I-D exandre.dalmax@honeywell. Stuff, Anyhow? 2005. http://electronicdesign. com). He has more than 202. Seiver, D.S., and Marin, O. (to Air Liquide com/Articles/ArticleID/6131/6131.html (ac- America Corp.), Adaptive control for air sep- years experience on the auto- cessed February 25, 2008). mation/computational engineering areas. Before aration unit, U.S. Patent 5,313,800, Septem- ber 2003. 7. Morrison, Don, Is it time to replace PID?, In- joining Honeywell, he held positions at Siemens Tech, March 2005. http://findarticles.com/p/ VAI, Dupont Safety Resources and ICSA do Bra-3. Midland Ross Corp., Apparatus For Catalytic articles/mi_qa3739/is_200503/ai_n13454538 sil. He holds the following academic degrees: Reforming, U.S. Pat. 3,617,227, 1971. (accessed February 25, 2008). Technical Professional in eletrical technology 4. De La Roza, Joaquin, Continuous digestion by the Centro Federal de Educação Tecnológica 8. Bandali, Zul, Air Separation Units Gets Fast de Minas Gerais (CEFET); Computational engi- apparatus for the production of highly puri- Fix, Chem. Proc., http://chemicalprocessing. fied cellulose, U.S. Pat. 2,542,801, Feb. 1951. neer by Universidade Federal de Minas Gerais com/articles/2008/002.html (accessed Febru- (UFMG), Brazil; and business, controlling and 5. Practical Process Control: Proven Methods ary 25, 2008). financing MBA by UFMG. ChemiCal engineering www.Che.Com September 2009 43
    • Circle XX on p. 62 or go to adlinks.che.com/23018-XXCircle 26 on p. 62 or go to adlinks.che.com/23018-26
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    • CHf CGf CHn CGn CAf CAf CAf = CAn Engineering Practice Feature Report CAn CAn CA(n–1) – CAn Xn = CA(n–1)CSTR Design CAn–1 CAn–1for Reversible CA1 – CA2 X2 = CA1 CA1 CA1Reactions CA0 – CA1 X1 = CA0 CA0 CA0 CAo CAo Here, a design approach for continuous Xf = CA0 – CAf CA0 = M > 1.0 Product: CA0 CGf and CHf stirred-tank reactors is outlined for three Plug-flow Multiple backmixed reactor reactors cases of second-order reactions Figure 1. Conversion in plug-flow reactors and CSTRs for second order reactions is shown here,Ralph Levine with conversion per stage shown for the CSTR caseM ultiple CSTRs (continuous stage, the number of stages of equal and CH0 are equal to zero, and the fol- stirred-tank reactors) are volume, as well as the volumetric ef- lowing expressions are true: advantageous in situations ficiency of the CSTR stages and the where the reaction is slow; plugflow reactor. CGf C A0 X ftwo immiscible liquids are present and The reactor design is developed by (2b)require higher agitation rates; or vis- selecting a conversion in the first stage.cous liquids are present that require Then, the second-stage conversion is CHf = C A 0 X f (2c)high agitation rates. Unlike in plug- equal to that of the first stage, sinceflow reactors, agitation is easily avail- it requires an equal volume. This pro- 2 2able in CSTRs. In this article, batch cedure is continued until the fraction C A0 X f C A0 C Af CGf CHfand plugflow reactors are analyzed of reactant exiting each reactor stage (2d)and compared to multiple CSTRs. reaches the desired value in the last The number of reactors required in stage, or slightly less than the plugflowa CSTR system is based on the con- case, as illustrated in Figure 1. The ratio may be different, as, for ex-version for each stage. When the final The kinetic rate conversion of a re- ample, the concentration of G in thestage obtains the fraction of uncon- versible bi-molecular reaction at con- product may be five times that of H.verted reactant that is equal to the stant temperature and flowrate is rep- However, we assume that the productsdesired final value from the plug-flow resented by Equation (1). The reaction are equal (CGf = CHf).case, the CSTR system is complete. is illustrated below (nomenclature is The volumetric efficiency of mul- defined on p. 49. Expressing reaction rate. The ratetiple CSTRs is expressed as a function equation can be modified to includeof conversion per stage and gives the 2A G H conversion and equilibrium constanttotal conversion required. In this ar- terms. Substituting Equations (1), andticle, we will apply this to reversible −r = kF C A 2 − kR CG CH (2d) into Equation (1) give an expres-second-order reactions. (1) sion for rate. kR kF K 2 22nd-order, reversible reactions (2) 2 r kF C A 0 1 X f kF K C A 0 X fThe first case presented here is akinetic process requiring a double 2 2 (3a) C A0 X f C A0 C Afcomponent (2A) to be fed to a reactor, (2a)and producing two products (G and CG 0 CGf CH 0 CHf X f2 K 1 r kF C 2 1 2 X fH). The design may be calculated for A0 Kboth CSTR and plug-flow reactors, de- Assume that G and H compounds aretermining the conversion in the first not present in the feed. Therefore, CG0 (3b)46 ChemiCal engineering www.Che.Com september 2009
    • K 1 2 V tion (11a), based on each stage having 2 r kF C A 0 Xf 2Xf 1 k C X ln 1 X f Xe v F A0 e (6b) the same volume and conditions. K 2 (3c) Volume of each CSTR stage. An ex- X1 CA2 C Ae C A1 C Ae 1At equilibrium, the net reaction rate pression for the first stage of a CSTR Xe C A1 C Ae C A 0 C Aeequals zero. is given in Equation (7). The first stage CA2 C Ae (11a) conversion, X1, occurs in each of the K 1 C A0 C Ae0 X e2 2 Xe 1 successive stages (X2, X3, and so on), K (4a) and each has the same volume and re- Continue this process for the nth stage action temperature. to obtain the following equations.Using the quadratic equation, Equa-tion (4a) is simplified to Equation (4c). V1 X1 n X1 C An C Ae vC A 0 r (7) 1 2 2 2 4 K 1 K Xe C A0 C Ae (12)Xe 2 K 1 K Substituting Equation (5c) into (7) and (4b) rearranging gives Equation (7a). X1 C An C Ae n log 1 log 1 1 1 K V1 CA 0 kF X1 X e Xe C A0 C AeXe K 1 K v 1 X1 X e (7a) (12a) (4c) n Equation (7a) has only one indepen- X1 Xf C An C AeThe quadratic equation can also be dent variable (V1). If each stirred reac- 1 1 (12b) Xe Xe C A0 C Aeused to simplify Equation (3c), result- tor stage is to be of equal volume anding in Equation (5a). volumetric flowrate, then the result is a constant conversion per stage. That Total volume of all stages. Substi- 2 4 41 1 K is, each stage, when at a fixed set of tute Equation (7a) into (13a).Xf 2 K 1 K conditions, has the same conversion VT nV1 (5) from each stage, expressed as: (13a) X1 = X2 = X3... = Xn 1 1 1 K VT V1 X1 X eXf kC n kC n K 1 K Number of stages. Conversion for v F A0 v F A0 1 X1 X e (5a) stage 1 is expressed by equation (8).The reaction rate expression can then (13b)be expressed as Equations (5b) and X1 C A0 C A1 C A0 (8) VT k C(5c). v F A0 The equilibrium conversion is based C C Ae (13c) 2 (−r = kF CA 0 X e − X f ) on time to reach a net reaction rate log An C A0 C Ae X1 X e (5b) of zero, which may be calculated by Equation (4b) or (9). log 1 X1 X e 1 X1 X e 2 ⎣ (−r = kF CA 0 Xe ⎡1 − X f X e ⎤ ⎦ ) (5c) Xe C A0 C Ae C A0 (9) By definition, CAn = CA0(1 – Xf), where Xf is the total conversion in the nthStirred reactor in a batch or plug- Subtract Equation (9) from (8) and di- stage or the final desired conversion offlow reactor. The batch reactor case vide by (9) to obtain Equations (10a) the plug-flow reactor. By the methodand the ideal continuous plugflow and (10b). used to obtain Equation (10), the fol-case are given in Equation (6). lowing equation is similarly derived. The reaction time is t for the batch (10) Substitution of Equation (12b) into Xe X1 C A1 C Ae C A0case, and V/v for the plugflow case. (13c) gives Equation (13d). X e − X1 C A1 − C Ae VT = ⌠ dX V Xf = k C ⌡0 −r (6) Xe C A 0 − C Ae (10a) v F A0vC A 0 (13d) log 1 X f X e X1 X eSubstituting Equation (5c) into (6) and C A1 C Ae 1 X1 X e log 1 X1 X e 1 X1 X erearranging, gives Equation (6a). C A0 C Ae (10b) V Xf dX The exit concentration, CA1, can be Volumetric efficiency ( k C2 X =vC A 0 F A 0 e ) ∫ 0 ( 1 − X f Xe ) calculated from Equation (10b). Also, Since VT/v in Equation (13c) is resi- the exit concentration from the second dence time, as is V/v in Equation (6b), (6a) stage, CA2, can be calculated from Equa- for CSTRs, these terms are equiva- ChemiCal engineering www.Che.Com september 2009 47
    • Table 1.VolumeTric efficiency for equaTion (14a) Engineering Practice (14a) X1/Xe Xe 1–(X1/Xe) log[1–(X1/Xe)] (V/VT)Xe V/VTlent. The volumetric flowrate is the 0.1 0.7 0.9 –0.046 0.948 1.355same in all cases (a batch operationfor one complete reaction cycle). Thus, 0.2 0.7 0.8 –0.097 0.893 1.275the ratio of comparison should be V for 0.3 0.7 0.7 –0.155 0.832 1.189plugflow or batch operation (reaction 0.4 0.7 0.6 –0.222 0.766 1.095volume and time only) compared toVT for multiple CSTRs. This ratio (V/ 0.5 0.7 0.5 –0.301 0.693 0.990VT), volumetric efficiency is expressed 0.6 0.7 0.4 –0.398 0.611 0.873as Equation (14), and is derived from 0.7 0.7 0.3 –0.523 0.516 0.737Equations (6b) and (13d). V 0.8 0.7 0.2 –0.699 0.402 0.575 k C X v F A0 e 0.9 0.7 0.1 –1.000 0.256 0.366 VT k C (14) TABLE 1. For any ratio of conversion per stage to equilibrium conversion, this table v F A0 provides the corresponding volumetric efficiency, based on Equation (14a) 2.303 log 1 X f X e M 1 The volumetric efficiency is calculated X1 X e log 1 X f Xe 0 X e2 Xe M KCB0 as Equation (23). 1 X1 X e log 1 X1 X e (18a) V Using the quadratic equation, Equa- VT tion (18a) becomes (18b). (23) V 2.303 log 1 X1 X e 2.303 1 X 1 X e (14a) 2 log 1 X1 X e M 1 M 1 Xe X 1 Xe VT X e X1 X e 4M KCB0 KCB0 log 1 X1 X e Xe (18b) 2 Reversible production of a dimer from twin reactantsVolumetric efficiency is independent Using Equations (17) and (18a), an ex- In another alternate but similar case,of the initial or final concentration pression for Xf is found. Equation (15) is modified for doubleand velocity constant at constant tem- M 1 components that are reversibly re-perature, as well as overall conver- r kF CB0 X f2 2 Xf M KCB0 acted to form a dimer, as shown in thesion. It is dependent on only the ratio (19a) reaction below. As in this last case,of the first stage conversion compared Equation (19a) can be simplified to there is only one product.to the equilibrium conversion. Calcu- Equation (19b) using the quadraticlations for Equation (14a) are shown equation. 2A Pin Table 1. 2 −r = kF C A 0 2 − kR CP M 1 M 1 (24) 4MReversible production of a KCB0 KCB0 (19b) CPf = C A 0 X fdimer from two reactants Xf (25)Another case exists, where two com- 2 2ponents are reversibly reacted to form r kF C A 0 2 1 Xf kF K C A 0 X fa single product, a dimer, rather than 2 r kF CB0 X e 1 X f Xe (19c) (26a)two products (as shown in the reaction 2 2below). This case is similar to the pre- r kF C A 0 Xf 2 KC A 0 X f 1 V1 kF CB0 X evious case, but but with only one prod- ln 1 X1 X e (20a) (26b)uct, as shown below in Equation (15). v At equilibrium, the rate is zero. The volume of each backmixed stageC D P is equal. 0 X e2 2 KC A 0 X e 1 (27a) r kF CB CD kR C p Using the quadratic equation, Equa- (15) V1 kF CB0 X e X1 X e tion (27a) becomes (27b). v 1 X1 X e (20b)CB0 X f CB0 CBf C pf (16a) X e 1 KC A 0 1 KC A 0 2 1 CB1 CBe (27b)C pf CB0 X f 1 X1 X e (16b) (21) CB0 CBe Xf 1 KC A 0 1 KC A 0 2 1 Xf (28a) CBn CBe r kF CB20 1 Xf M Xf 1 X f Xe r kF C A 0 12 X f Xe KCB0 CB0 CBe (28b) n (17) 1 X1 X e (22) For a plugflow reactor, the followingAt equilibrium, the rate is zero. expression is true.48 ChemiCal engineering www.Che.Com september 2009
    • Summary of equatioNS Subscripts [6] NomeNclature 0 Initial conditions B D P S 1,2,3 First, second and third stages 2 M 1 M 1 4M 1 K K C Concentration, A For component A Xe moles/unit volume C For component C 2 K 1 K k Reaction rate constant D For component D 2 K Equilibrium constant e Equilibrium conditions M 1 M 1 4M 1 K K Xf M Initial mole ratio of D/B f Overall or final conditions 2 K 1 K n Number of stages F Conditions for forward reaction 2A G H G For component G r Reaction rate 1 1 1 K t Reaction time H For component H Xe V Reactor volume j Any stage in the series of reactor stages K 1 K n The nth stage v Volumetric flowrate X Conversion P For component P 1 1 1 K Xf R Conditions for reverse reaction K 1 K T The total of all n stages C D P 2 References Author M 1 M 1 Ralph Levine is a retired 4M 1. Levenspiel, O., “Chemical Reaction Engi- chemical engineer currently KCB0 KCB0 neering,” John Wiley & Sons, Inc., 1962. working as a consultant Xe 2. Levine, R., Hydro. Proc., July 1967, pp. for plants, design or opera- 2 158–160. tions and R&D (578 Arbor 2 Meadow Dr., Ballwin, Mo. M 1 M 1 3. Levine, R. A New Design Approach for 63021; Email: ralphle2000@ 4M Backmixed Reactors — Part I, Chem. yahoo.com). Levine earned a KCB0 KCB0 Eng. July 1, 1968, pp. 62–67. B.S.Ch.E. from the City Uni- Xf 4. Levine, R. A New Design Approach for versity of New York, and did 2 Backmixed Reactors — Part II, Chem. graduate work at Louisiana Eng. July 29, 1968, pp. 145–150. State University and the Uni- 2A P versity of Delaware. Levine later served as an 2 5. Levine, R. A New Design Approach for engineer for the U.S. Army Chemical Corps. He X e 1 KC A 0 1 KC A 0 1 Backmixed Reactors — Part III, Chem. has worked for DuPont, Cities Service Co., and Eng. Aug 12, 1968, pp. 167–171. most recently, Columbian Chemical Co. Levine 2 6. Levine, R. CSTRs: Bound for Maximum has filed several U.S. patents during his career, Xf 1 KC A 0 1 KC A 0 1 Conversion, Chem. Eng. Jan. 2009, pp. and is a published author, with his work fea- 30–34. tured in Chemical Engineering and Hydrocar- CPD-5 8/20/07 10:34 AM Page 1 bon Processing.V C A 0 kF X e ln 1 X f Xe (29) vThe expression for multiple CSTRs isgiven as Equation (30). The best way to heat and coolV1 C A 0 kF X1 X e (30) the most corrosive materials. v 1 X 1 Xe n 1 X1 X e 1 X f Xe C An C Ae (31) C A0 C Ae Nothing controlsThe volumetric efficiency is found to temperatures ofbe Equation (32). corrosives and high purity materials better V 2.303 1 X1 X e than AMETEK fluoropoly- (32) VT Xe X1 X e mer heat exchangers. Not glass. Not silicon carbide log 1 X1 X e or graphite units. AvailableThe last two cases presented here are with steel or non-metallicreversible and have only one product. shells, diameters from 3"The differences between these cases to 14" and metric designs,are the values calculated based on AMETEK heat exchangersthe quadratic equation for both Xe include TEMA/ANSI nozzle andand Xf. All second order reactions that end connections. To learn moreare reversible and produce one or two call (302) 456-4431 or visit:products require the quadratic equa- www.ametekfpp.comtion for the calculation of Xe and Xf foreach case. A summary of these equa-tions is presented in the box above. ■ Edited by Kate Torzewski Circle 27 on p. 62 or go to adlinks.che.com/23018-27 ChemiCal engineering www.Che.Com september 2009 49
    • Engineering Practice No torches, fewer burn hazards and outstanding fire characteristics make CPVC a safe, effective alternative for industrial pipingCPVC Piping In Chemical Environments:Evaluating the Metallic pipe safety concerns Statistically speaking, metal domi- nates the industrial piping market. Still today, a large number of chemi-Safety Record cal processing plants utilize some grade of steel for their industrial pip- ing system. This is somewhat surpris- ing when considering the wide array of safety risks associated with metal. When referring to safety, this authorDonald Townley, The Lubrizol Corp. is considering risks associated with installation, maintenance and ongo-T here are many considerations savings. Meanwhile, there is a certain ing operation. when choosing piping materials reliability benefit, since CPVC has ex- Starting with installation, metal for an industrial system. Histori- cellent resistance to a broad range of piping presents two primary safety cally, when options were more corrosive environments. hazards. The most serious is the firelimited, the decision-making process When considering which material risk associated with the open flame ofwas relatively straightforward. It offers the best solution for a specific the welding torch required to installwas a matter of choosing what grade application, a number of criteria com- a metallic piping system. This is anof metal to install. Today, there is a monly top the priority list. Is the ma- important consideration whether thelarger array of high-performance, non- terial compatible with the chemistry project involves new construction ormetallic options to also consider. Chlo- of the liquids being transported? Is it plant upgrades (additions). However,rinated polyvinyl chloride (CPVC) is designed to meet the specific tempera- the risk is greatest when a line is beingan example of a newer generation of ture and pressure requirements of the replaced or added to an existing oper-materials. Although it has a proven system? What is the projected life of ation because of the possible proxim-50-yr track record in industrial envi- the system? Will it perform reliably ity of hazardous chemicals and otherronments (having been invented by over the life of the system without flammable materials. Due to the in-The Lubrizol Corp., formerly BFGoo- requiring costly, periodic downtime? herent fire risks associated with weld-drich Performance Materials, back in How easy is the system to install and ing, a metal pipe installation requires1959), it has made major inroads in maintain? And, of course, the big ques- a hot work permit, which requires athe past decade into numerous indus- tion on everyone’s mind is how much time-intensive approval process.trial applications. will the system cost to install and op- A second safety concern during the There are many reasons why CPVC erate over the long term? installation process relates to thepiping is specified more often today. In an industrial setting that is weight of metal piping. As a heavier(for more on specifying CPVC, see CE, closely monitored and regulated by material (relative to most non-metallicOctober 2006, pp. 34–38) Better educa- the U.S. Occupational Safety and piping), metal creates the additionaltion and general awareness of the high- Health Admin. (OSHA) and Environ- risk of worker strains and sprainsperformance thermoplastic have cer- mental Protection Agency (EPA) stan- during installation. The weight cre-tainly factored into the market shift. dards and where hundreds, or even ates the additional need for heavyIn addition, ongoing price increases thousands, of lives are at stake, there machinery on the job site, which canfor metal products are also pressuring is one other significant consideration create its own safety concerns.bottom-line conscious owners and spec- — the safety performance of the pip- Once a metal piping line is up andifiers to search for more cost-effective ing material. This article highlights running, a significant safety concernoptions. Fast and easy installations are common safety concerns associated stems from its burn potential. Metalcertainly a contributing factor, as this with some of the most popular piping is a tremendous heat conductor, whichnot only contributes to the installer’s materials on the market today and means it transmits heat easily fromability to complete the project on time, compares their overall performance the interior to the exterior of the pipe.but can also result in significant cost from a safety perspective. Contact burn injuries are addressed50 ChemiCal engineering www.Che.Com september 2009
    • Weak acids Weak bases Salts Figure 1. uous tests, not only in the laboratory Strong acids CPVC stands up under simulated real-world conditions, to many of the same aggressive but also in actual pulp and paper mills Excellent Aliphatics Strong bases chemicals that and other CPI plants. Since not all corrode steel solvent cements are derived from the Good Strong oxidants same chemistries, it is critical to al- Halogens ways check product labels and, if in Fair doubt, talk directly with the manufac- Aromatic solvents turer to ensure that the solvent cement Poor Esters and ketones is designed for a specific application. Solvent safety. One safety concernby OSHA guidelines and are covered CPVC also completely eliminates that had been linked with the solventby ASTM, which has developed its the fire risk of welding pipe. Instead, cements used with CPVC pipe and fit-Standard Guide for Heated System CPVC systems can be installed by tings in years past was the presenceSurface Conditions that Produce Con- solvent cementing, flanging or thread- of volatile organic compounds (VOCs).tact Burn Injuries. Depending on the ing. Any piping modifications or pipe Fortunately, there has been a majortemperature of the fluid being con- repairs can also be made equally trend in the industry, as a result ofveyed, the potential for burns must be quickly, easily and safely without the tougher ASTM standards and othermitigated with the addition of insula- need for a welder or lifting device to protocols, for manufacturers to reducetion around the pipe. At this point, the hoist equipment into place. This also the level of VOCs in the solvent ce-conductivity of metal not only repre- means avoiding the hassle and delays ments they manufacture. Although itsents a safety concern, but also a cost of requesting a hot work permit. is still important to check the productconcern, since the addition of insula- Cementing. Solvent cementing, which label to determine the level of VOCstion increases the overall cost of any is by far the most common installation in a specific product, many leadingpiping project in the form of increased method used for CPVC industrial pip- manufacturers have chosen to meetlabor and material costs. ing systems, creates a highly reliable the most stringent VOC emission By far the greatest ongoing safety joint by chemically fusing the pipe to limits in the U.S. — those set by Ruleconcern associated with a metallic the fitting. When installed correctly, a 1168/316A, which was established bypiping system, however, is the risk of solvent-cemented CPVC joint actually California’s South Coast Air Qualityleaks and premature failures as a re- becomes the strongest part of the en- Management District (SCAQMD).sult of corrosion. The financial rami- tire system, offering more durability Proper safety precautions shouldfications of leaking pipes are obvious than either the pipe or fitting alone. still be followed. Similar to the guide-and include downtime, possible prop- This contrasts sharply with metallic lines in place when welding metallicerty damage, and the actual repair or systems and other plastic piping ma- pipe, there are common-sense safetyreplacement costs for the failed pipe- terials for which the joint is often the guidelines that should be followedline. An overriding consideration, and most vulnerable and likely to be the when solvent cementing CPVC pipeone that cannot be measured in dol- source of initial leaks. and fittings. Just as you wouldn’t wantlars, is the risk to plant workers from Solvents. Despite the proven superi- to inhale the gases generated whilea leaking pipe. The exact chemical ority of CPVC solvent-cemented joints, welding steel pipe, neither should youmakeup of the fluid being transported, it is important to choose the right sol- inhale solvents. Always ensure ad-as well as its temperature, will deter- vent cement for a given application. equate ventilation, especially whenmine the severity of the risk. The chemical process industries (CPI) working in confined spaces where routinely use many strong, inorganic there is little or no air movement.CPVC: A safer alternative acids, bases and salts, some of which Proper eye protection should also beChoosing a non-metallic alternative, may be chemically incompatible with worn to prevent solvents from splash-such as CPVC, eliminates, or at least the fillers used in standard solvent ing into the eyes. Special solvent-re-minimizes, all of the safety risks men- cements. That’s why, beginning in the sistant gloves should also be used totioned above that are typical of any late 1990s, newer-generation solvent prevent epidermal absorption. Due tometallic pipe installation. cements were tested and developed to the vapors that could be ingested, in-Installation. Starting with the in- resist chemical attack. These specially stallers should not eat, drink or smokestallation process, CPVC is often formulated CPVC solvent cements are when using solvent cement. And,preferred because it is lightweight — designed to handle even the strongest since solvents are flammable, alwaysroughly one eighth the weight of com- oxidizing chemicals, such as sodium take care to avoid working near openparably sized steel pipe. Not only does hypochlorite, sulfuric acid and other flames or sparks.its lightweight design minimize the highly aggressive caustics. Over the Corrosion. Once installation is com-risk of worker injuries, but it typically more than ten years since their in- plete, CPVC offers many additionaleliminates the need for heavy equip- troduction to the market, these high safety advantages over traditionalment, which can present additional strength, chemical-resistant solvent metallic systems — starting with asafety risks. cements have been subjected to stren- highly reliable performance. In a large ChemiCal engineering www.Che.Com september 2009 51
    • Estimated pipe surface temperature vs. internal fluid with 73 °F (23 °C) air circulating at 0.75 ft/s Estimated pipe surface temperature, °C Estimated pipe surface temperature, °F 180 Engineering Practice 170 80 75 160 70 Steel, all sizes Figure 2. At el- 150 65percentage of metallic piping failures,corrosion is identified as the root cause. evated internal-fluid 140 60 temperatures, the 3-in., schedule 80 CPVC pipeCorrosion can occur for any number of surface temperature 130 55reasons but, in the most basic sense, of CPVC pipe is sig- 50 120it is classified into two major catego- nificantly lower than 45ries. Internal corrosion, which is the the internal fluid 110 12-in., schedule 80 CPVC pipemost common, results from chemicals temperature 40 100inside the transported fluid eating 140 145 150 155 160 165 170 175 180away at the metal surface. External Internal temperature, °Fcorrosion, as the name implies, resultsfrom salts or acids that are in the air — approximately 1/300th that of steel. the past, materials such as polypro-(or in the ground in the case of buried As a result, the surface temperature of pylene (PP) and standard PVC havepipelines) and are incompatible with CPVC pipe is significantly lower than often been specified for low-temper-the metal surface. Whether the prob- the internal fluid temperature. Metal, ature process fluids. The problem islem starts from the inside of the pipe on the other hand, because of its high that, as a result of the sun and ambi-and works its way out, or vice versa, thermal conductivity, will have an ent air temperature, pipe (even whenthe outcome is the same — a costly exterior surface temperature nearly painted white) retains heat. Recentand potentially unsafe chemical leak. equal to the temperature of the fluid testing has confirmed that this heatAn overhead leak presents additional being conveyed (Figure 2). buildup can cause the pipe’s surfaceconcerns for workers, while a leaking The actual surface temperature of temperature to rise above the maxi-pipe outdoors or underground could pipe in a working system is dependent mum temperature rating of 170°F forpotentially represent serious environ- on many factors, including ambient PP and 140°F for PVC. The actual sur-mental concerns. temperature, air circulation velocity face temperature is dependent on fac- But CPVC stands up to many of the and direction. ASTM sets very specific tors such as the ambient temperaturesame aggressive chemicals that cor- standards with regard to acceptable the color of the pipe, angle of the sun,rode steel (Figure 1), and it does so in surface operating conditions for heated surface and air conditions. So even ifvery extreme temperature environ- systems. Within the ASTM guide (Des- the outside temperature is only 95°Fments. In fact, CPVC is pressure rated ignation: C1055-03) is a specific nota- for PP pipe or 80°F for PVC pipe, thefor temperatures up to 200°F. That tion that if the surface temperature surface temperature could easily bemakes it ideally suited, with mini- exceeds 70°C (158°F) and the surface greater than the temperature ratingmized safety concerns, in a number of is metallic, it may present a hazard of the material. The surface tempera-process industries, including chemical, regardless of contact duration. It ad- ture of CPVC pipe, on the other hand,pulp and paper, metal treating, chlor- ditionally notes that non-metallic skin would not be expected to exceed thealkali, fertilizers, mining, wastewater contact may be safe for limited expo- 200°F temperature rating even whentreatment and semiconductors. That’s sure at temperatures above 70°C. the ambient temperature reachesnot to say that CPVC is suitable for all 120°F (Figure 3).applications. Like metal, it also has its CPVC versus other plastics Heat buildup is a problem for alllimitations and areas where it cannot Much of this article has addressed the plastics, because every plastic mate-be used safely. For example, CPVC is safety attributes of CPVC as they com- rial has a maximum pressure ratingnot recommended for use with most pare to metal. This is largely because after which point its performance andpolar organic materials, including metal is still frequently specified in reliability are compromised (unlikevarious solvents. many applications where CPVC has metals with pressure ratings thatContact burns. Contact burn inju- proven to be a more cost-effective, re- are not significantly affected by tem-ries were also previously discussed liable and safer alternative. However, perature). So whether you’ve installedas a risk when working around metal there are a number of applications CPVC, PVC or PP, you need to considerpiping systems. Hyperthermia (high where plastics other than CPVC are more than just the process tempera-temperature exposure) is a very real being considered. ture if the pipe is going to be outdoors.threat in many chemical processing All piping materials have their It is the surface temperature that af-environments and can lead to irre- strengths and weaknesses. And in fects performance. This reinforces theversible damage. The chemical reac- some cases, there may be more than need to consider all variables whentions occurring within the skin cells one material that is well suited for a choosing a particular piping materialupon exposure and the relationships specific application. However, there because, in this case, the ambient tem-between exposure temperature and are a number of situations for which perature could have a major effect onduration on the transfer of heat into CPVC offers additional safety benefits the final performance.the skin have been subjects of exten- over other plastics. Fire performance. When comparingsive research. Outdoor installations. Consider, for CPVC to other plastic piping materi- Safety-conscious specifiers should example, pipelines that are installed als, another key safety considerationbe interested in noting that CPVC has outdoors and subject to the effects of is the product’s fire performance. Nota very low thermal conductivity value the sun and ambient temperature. In all plastics exhibit the same fire per-52 ChemiCal engineering www.Che.Com september 2009
    • Effect of direct sunlight on material temperature and pressure rating using ASTM D4803when exposed to direct sunlight Surface temperature, °F 200 190 CPVC is pressure rated up to 200°F. 180 The surface temperature of CPVC will not exceed its pressure/temperature 170 rating even in the extreme case of 120°F 160 PP is pressure rated to 170°F outdoor conditions 150 CPVC pipe 140 PP pipe PVC is pressure (green) 130 rated to 140°F PVC pipe 120 (painted white) 70 80 90 100 110 120 Outside temperature, °F Figure 3. This chart shows that, under the most severe conditions (clear skies, no wind, sun perpendicular to the specimen), significant heat buildup can occur through the pipe wall due to the effects of solar radiation. This greatly affects the temperature/ pressure ratio of the pipe material, even at moderate temperatures (Heat buildup was calculated using ASTM D4803 standard) formance characteristics in terms of testing than many traditional materi- flame propagation and smoke genera- als to ensure a reliable performance, tion. But CPVC rates well in both cat- superior durability and long service egories — an important consideration life — all factors that can affect the in case of a catastrophic incident. overall safety of an industrial piping CPVC has a flash ignition tempera- system. Testing has included mini- ture of 900°F. This is the lowest tem- mum burst pressure requirements, di- perature at which combustible gas can mensional tolerances, residual stress be ignited by a small, external flame. requirements, drop impact require- Many other ordinary combustibles, ments and fusion property testing. such as wood, ignite at 500°F or less. The reality is that CPVC can be Furthermore, CPVC will not sus- safely used in systems throughout tain burning. It must be forced to nearly any industrial plant because burn due to its exceptionally high of its durability, long service life and limiting oxygen index (LOI) of 60. high performance characteristics. LOI is the percentage of oxygen CPVC industrial piping systems offer needed in an atmosphere to support numerous benefits to industrial pro- combustion. Because the Earth’s at- cessing plants — most notably in their mosphere is only 21% oxygen , CPVC ability to stand up to aggressive chem- will not burn unless a flame is con- icals and high temperatures. These stantly applied. Burning stops when features, combined with superior cor- the ignition source is removed. Other rosion resistance, help make CPVC a plastics have a much lower LOI — PP, safe, smart material choice in many for instance, has an LOI of 18 — and, industrial environments. as a result, will burn after the flame When teamed up with its excel- source has been removed. lent balance of mechanical strength, low thermal conductivity, and limited Final remarks flame propagation and low smoke gen- One of the most critical factors in the eration, CPVC provides an excellent successful design, installation and value in terms of safety. n operation of a safe industrial piping Edited by Gerald Ondrey system is the use of a material that best suits the application. No single Author Donald Townley is the material is right for all applications. market manager for Cor- All materials, whether metal or plas- zan Industrial Systems, which is part of The Lubri- tic, have strengths and weaknesses zol Corp. (9911 Brecksville Road, Cleveland, OH 44141. and perform differently given varying Phone: 216-447-5244; Fax: temperatures, environments, flow- 216-447-6211; Email: donald. townley@lubrizol.com). Town- rates and pressures. ley has been with Lubrizol For those people responsible for for 19 years. Prior to this, he worked for eight years with specifying materials that are both BP. He holds a B.S.M.E. from the University of cost-effective and safe, it’s important Cincinnati, and an M.B.A. from Kent State Uni- versity. Townley is a registered PE in the state to note that CPVC has undergone more of Ohio.
    • Focus onValves Swagelok Emerson Process ManagementNew radial diaphragm valves blades, as well as redesigned air ventsimprove cleanability to help minimize leakage and optimizeA single-body valve design with bore- venting. The new rotary valves are minimiz- enables complete shutoff. By minimizline seal that minimizes entrapment available for medium (22 psi) to high ing contact between the seal ring andareas is responsible for the ease of (50 psi) pressure applications, and for the valve disk, seal wear is reduced.cleaning. The DR Series of valves conveying capacities of between 4,500 A related product from the same com-(photo) is designed for sterile flow lb/h and 220,000 lb/h. — Pelletron pany is a newly introduced butterflystreams in media preparation, fer- Corp., Lancaster, Pa. valve offering high throttling per-mentation, separation, petroleum re- www.pelletroncorp.com formance, ideal for applications thatfining, purification and other applica- involve fast processes and varyingtions. The valves can be manufactured These sampling valves are de- pressure drops. — Emerson Processin a variety of configurations and sizes signed for ease of use Management, Hatfield, Penn.from ½ to 2 in. Made of 316L stain- “Quick Advance” (QA) sampling www.emersonprocess.comless steel with modified PTFE wetted valves offer “ease of use” in collectingsingle-piece diaphragms, the valves truly representative samples. The QA This valve packing achievescan accommodate system pressures valves employ a rack and gear com- ultra-low emissionof up to 150 psig and operating tem- bination that provides a full piston A new low-emission valve stem spoolperatures up to 137°C. Also offered motion while the handle only travels packing delivers emissions perfor-are stream selection valves to deliver one-third of a turn. Valve design also mance of <20 ppm average leakage.samples to a single analyzer. The SSV reduces dead space to eliminate the Two unique types of graphite pack-Series houses double-block, bleed and need to purge the valve prior to collec- ing comprise the new style 212-ULEactuation functions within a single tion. The valve line is compliant with product. The new packing is self-lu-compact module. — Swagelok Co., international standards and is avail- bricating for low valve-stem friction,Solon, Ohio able in a range of materials. — Strah- nonhardening, dimensionally stablewww.swagelok.com man Valves Inc., Bethlehem, Pa. and corrosion-resistant. The pack- www.enr-corp.com ing can withstand temperatures ofAchieve lower air leakage with –200°C to 650°C in steam and non-these rotary valves This rotary valve is designed for oxidizing environments (up to 455°CNewly designed rotary valves for pneu- complete shutoff and long life in media containing free oxygen) andmatic conveying of granular products The POSI-SEAL rotary valve (photo) its maximum pressure rating is 4,500feature expanded tips at the ends of is suited to on/off process applications psig. — Garlock Sealing Technologies,rotor blades to reduce air leakage. The requiring tight shutoffs. The pressure- Palmyra, N.Y.valves have an increased number of assisting action of the valve seal ring www.212ULE.com54 ChemiCal engineering www.Che.Com September 2009 Note: For more information, circle the 3-digit number on p. 62, or use the website designation.
    • Vortex Valves has the same face-to-face dimensions as plug or ball valves up to 12 in. The valve can also function as a throttling manual-control valve. — Red Valve HF Inverting Company Inc., Carnegie, Pa. Filter www.redvalve.com Centrifuge This valve is available in manual or actuated models Cutting edge centrifuge technology for DAB Series diaphragm valves can be filtration, washing and drying of operated manually or actuated pneu- solid/liquid suspensions matically or electrically. The valves • Increase production • Improve productivity - Thin Cake are constructed of all plastic, and Processing engineered to handle difficult media, • Eliminate Operator Exposure - Full such as corrosive fluids, abrasive mix- Containment tures and slurries. DAB Series valves • Effective Automated CIP feature a multi-turn design for con- • Widest Range of Applications - Hardest to Easiest Filtering Products trol, are self-draining to reduce or • Lowest Possible Moistures - PAC ™ eliminate dead volume, and are rated Technology to 150 psi. — Haywood Flow Control • Dry Product Inside the Centrifuge - Systems, Clemmons, N.C. PAC™ Technology www.haywardflowcontrol.com A valve control system with on- Conical Vacuum board diagnostics capability Dryer - Mixer The Axiom valve control system now Advanced technology offers an on-board diagnostics abil- for simultaneous multi-function ity to predict potential problems in drying and mixing automated valves, thereby reducing process downtime and maintenance costs. The system can sound local and • Full Containment OperationUse this device to lock out remote alerts for such occurances as • Largest Heat Transfer Surface Areaplug valves a jammed valve or actuator, a drop in • Automatic CIP • Handles the Widest Range of MaterialsA new device to lockout plug valves pneumatic supply or an open solenoid • Variable Volume Batch Sizesis now available. The easy-to-use de- circuit. Alerts are cleared when nor- • Gentle Low Shear Drying & Mixingvice secures manually actuated plug mal operating conditions are restored. • Quick & Trouble Free Productvalves and can be used to comply with — StoneL Corp., Fergus Falls, Minn. Dischargingrelevant Occupational Safety and www.stonel.comHealth Administration (OSHA) regu- Pennwaltlations. Available in four sizes to fit This line diverter can handle Super-D-Canterplug valves from 1 to 8 in. in diameter, positive or negative pressures Cutting edge continuousthe device is compatible with plug The Quantum series line diverter centrifuge technologyvalves from many manufacturers. The (photo) can accommodate either for separation ofvalve lockout device has a base that re- positive or vaccuum pressures of slurries into liquid ormains in place once applied and does up to 15 psig in pneumatic convey- solid phases.not interfere with valve activation by ing systems. The four-way diverter • Only (1) drive motorwrench or removable handle. — Brady can direct dry bulk material to four • High Abrasion Points are fitted with replaceable partsWorldwide Inc., Milwaukee, Wis. destinations or converge material • Advanced Polymer injection systemwww.bradyid.com from four sources to one destination, • Most economical cost and is available in 2-in. to 6-in. pipe Ideal for:This valve is designed for slur- or tube diameters. A wide range of • Ethanol Stillage Dewateringries and corrosives. modifications are available for the • Sludge Thickening & Dewatering • Chemical Intermediates & Fine ChemicalThe Series 75 pinch valve is designed diverter valve to allow its use in • Production of Plastics (PVC Dewatering)to alleviate difficulties associated with high- and low-temperature or humid • Clarification of Liquidsball and plug valves in applications environments, as well as with corro- • Distillery Stillageinvolving tough slurries, and abrasive sive or hazardous materials. —Vor-or corrosive chemicals. Its full port de- tex Valves NA, Salina, Kan.sign eliminates dead spots, crevices, www.vortexvalves.com ■seats and bearings. The pinch valve Scott Jenkins Circle 29 on p. 62 or go to adlinks.che.com/23018-29
    • SEALS/GUARDS 2C AD-07 8/15/07 8:59 AM Page 1ProDUCt SHOWC ASE Krytox ® Fluorinated Lubricants 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 FKMKrytox® Fluorinated Greases and Oils diaphragms.are: Chemically Inert. Insoluble in commonsolvents.Thermally stable.Temperature range • PVC, Polypro or(-103˚F to 800˚F). Nonflammable. Nontoxic. PVDF bodies.Oxygen Compatible - safe for oxygen serv-ice. Low Vapor Pressure. Low Outgassing. No • Available withMigration - no silicones or hydrocarbons. or withoutKrytox offers Extreme Pressure, Anticorrosion gauges.and Antiwear properties. Mil-spec, Aerospaceand Food Grades (H1 and H2) available! • GaugeUseful in Vacuum Systems. Shields forWe also offer a complete line of inert harsh environments.fluorinated Dry Lubricants and ReleaseAgents.For technical information, call 203.743.4447800.992.2424 (8AM - 4 PM ET). m smiller-stephenson chemical company, inc. PLAST-O-MATIC VALVES, INC. California - Illinois - Connecticut - Canada CEDAR GROVE, NJ 07009 e-mail: support@miller-stephenson.com (973) 256-3000 • Fax: (973) 256-4745 www.miller-stephenson.com www.plastomatic.com • info@plastomatic.com Circle 201 on p. 62 or go to Circle 202 on p. 62 or go to Circle 203 on p. 62 or go to adlinks.che.com/23018-201 adlinks.che.com/23018-202 adlinks.che.com/23018-203 Software CA Co PE-O mp PE lian N t! Circle 241 on p. 62 or go toHTRI Xchanger Suite® – an integrated, easy-to-use suite of tools that adlinks.che.com/23018-241delivers accurate design calculations for engineering e-material, e-solutions, e-courses • shell-and-tube heat exchangers • fired heaters and e-seminars for energy conversion systems: • jacketed-pipe heat exchangers • air coolers • Physical Properties • Steam Approximations • Power Cycles • Power Cycle Components/Processes • hairpin heat exchangers • economizers • Compressible Flow ENGINEERING SOFTWARE • plate-and-frame heat exchangers • tube layouts Phone/FaX: (301) 540-3605 web Site: http://www.engineering-4e.com • spiral plate heat exchangers • vibration analysis Visit the web site to check out free demos etc.!Interfaces with many process simulator and physical property Circle 242 on p. 62 or go to adlinks.che.com/23018-242packages either directly or via CAPE-OPEN.Heat Transfer Research, Inc.150 Venture Drive HTRI@HTRI.net www.HTRI.net Get CoNNeCteD toDaYCollege Station, Texas 77845, USA Circle 240 on p. 62 or go to adlinks.che.com/23018-240 www.che.com56 ChemiCal engineering www.Che.Com SePTemBer 2009
    • 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 wastesSuperPro Designer is a comprehensive process simulator that facilitates modeling, cost analysis, debottlenecking, cycle timereduction, and environmental impact assessment of biochemical, specialty chemical, pharmaceutical (bulk & fine), food, consumerproduct, mineral processing, water purification, wastewater treatment, and related processes. Its development was initiated at theMassachusetts Institute of Technology (MIT). SuperPro is already in use at more than 400 companies and 500 universities aroundthe 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 thatdo not violate constraints related to the limited availability of facilities, equipment, resources and work areas. It can be used inconjunction with SuperPro (by importing its recipes) or independently (by creating recipes directly in SchedulePro). Any industrythat manufactures multiple products by sharing production lines and resources can benefit from the use of SchedulePro. Engineeringcompanies use it as a modeling tool to size utilities for batch plants, identify equipment requirements, reduce cycle times, anddebottleneck facilities. Circle 243 on p. 62 or go to adlinks.che.com/23018-243 Visit our website to download detailed product literature and functional evaluation versions of our tools INTELLIGEN, INC. • 2326 Morse Avenue • Scotch Plains, NJ 07076 • USA Tel: (908) 654-0088 • Fax: (908) 654-3866 Email: info@intelligen.com • Website: www.intelligen.com Intelligen also has offices in Europe and representatives in countries around the world
    • RecRuitment The TECHNISCHE UNIVERSITÄT MÜNCHEN is creating a new core competence in its                         strategic development through trans-disciplinary teaching and research activities. New  professorships are being created to stimulate activity across the faculties. To this end,   these professorships will require teaching and research in two or more faculties.  TUM Center for Electrical Mobility  Chair for Technical Electrochemistry   research center for electrical mobility is being developed in the MUNICH    A              SCHOOL                OF ENGINEERING with the participation of several faculties of engineering and natural  sciences. In this context a new chair for Technical Electrochemistry will be created under   the leadership of the faculty for chemistry. A complete concept for an economically and technologically promising electric vehicle of the future will be developed in the Center    Mobility. for Electrical                                        The scientific emphasis of the professorship will be the fundamentals of electrochemistry,   in particular in the development of new electrochemical storage for electrical mobility.    intended   existing activities  storage cell technology The professorship is   to strengthen   in      by improving the current technologies as well as developing completely new storage   systems. We are looking for an internationally distinguished individual with research   achievements in the area of electrochemical systems.                         well as   The teaching activity will cover the complete range of electrochemistry as  energy sciences. The professorship will also include participation in the planned master course  of studies for electrical mobility, as well as related courses of studies which will be set   up. Appointment is planned at the level of Full Professor (W3).    Formal requirements for the professorship are a university diploma, teaching qualifications and a PhD degree. Excellent research accomplishments are obligatory; these may   or a formal have been gained outside of academia. Postdoctoral teaching experience  lecturing qualification is required. Applicants should not have passed the age of 52 at      exceptions to the age limit are possible.  the time of their nomination. Well justified                           Persons with disabilities will be given preference over other applicants with comparable qualifications. The TECHNISCHE UNIVERSITÄT MÜNCHEN is striving to increase the proportion of women in research and education. Female scientists are therefore especially encouraged to apply for this position. Applications including CV, credentials, publication list, a short overview of research interests and relevant documents should be sent by September 30, 2009 to Prof. Dr. Thorsten Bach, Dean of the Faculty of Chemistry, TECHNISCHE UNIVERSITÄT MÜNCHEN, Lichtenbergstr. 4, D-85747 Garching, Germany. Circle 244 on p. 62 or go to adlinks.che.com/23018-24458 ChemiCal engineering www.Che.Com SePTemBer 2009
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    • Economic Indicators Business neWs construct a treatment plant with capacity to Teijin Nestex textile dyeing company willPlant Watch process approximately 150-million gal/yr of dissolve and liquidateCement plant expansion in the Ukraine washwater.The treatment process will take August 3, 2009 — Teijin Fibers Ltd. (Osaka, Ja-decreases environmental emissions byproducts from the distillation process and pan; www.teijinfiber.com) has announcedAugust 20, 2009 — ABB Switzerland Ltd. (Zur- turn them into clean water and biogas for plans to withdraw from the operations ofich, Switzerland; www.abb.com) has won an green energy.This process enables Diageo Teijin Group’s core textile-yarns dyeing plant,order from international building materials to recycle water, provide a clean source Teijin Nestex Ltd., based in Ishikawa, Japan,group CRH to deliver electrical and auto- of energy to its distillery, and create a rich and to dissolve and liquidate the companymation equipment for Podilsky Cement’s fertilizer that can be used by public/private at the end of March 2010.Teijin Nestex’snew production line. Once the project is organizations. Diageo is already in talks with predecessor Daishojiseren Ltd. joined thecompleted, the cement production line will organizations that are interested in using Teijin Group in 1951 and the company hashave a daily output of 7,500 tons.The Podilsky the fertilizer. Once in operation in 2010, the functioned as the Group’s core textile-yarnsCement factory, located near Kiev, is one distillery will have the capacity to distill up to dyeing plant for approximately 50 years.of the biggest cement plants in the Ukraine. 20-million gal/yr of rum. During this time, the increasing shift of textileThe expansion project will help the plant manufacturing offshore has significantlydecrease emissions from fossil fuel combus- hampered the company’s profitability.tion by changing the technology of cement Mergers and acquisitionsproduction from a wet production process to Solvay increases investment in innovative Arkema to buya state-of-the-art dry production process. printed electronics certain assets from Dow August 20, 2009 — By investing $12 million, August 3, 2009 — Arkema (Colombes,KBR awarded contract for Solvay (Brussels, Belgium; www.solvay.com) France; www.arkema.com) and The Dow refinery in Angola... has become the largest minority sharehold- Chemical Co. (Midland, Mich.; www.dow.August 20, 2009 — KBR (Houston; www.kbr. er in Plextronics, Inc. (Pittsburgh, Pa.; www. com) have entered into an agreement forcom) has been awarded a contract by plextronics.com). Plextronics specializes in Dow to meet U.S. Federal Trade Commis-Sonangol, E.P. to provide license and engi- the development and commercialization sion (FTC)-required divestitures relatedneering services for fluid-catalytic-cracking of polymer-based technologies for printed to its acquisition of Rohm and Haas.This(FCC) and hydroprocessing technologies electronics, such as organic solar cell and comes ahead of the November 27, 2009for the Sonaref Refinery to be located in OLED (organic light-emitting diode) lighting. deadline. Arkema will buy a Clear Lake,Lobito, Angola.The 200,000-bbl/d grassroots Tex., acrylic acid and esters plant and therefinery is being built to reduce the country’s SABIC and Mitsubishi Rayon UCAR Emulsion Systems specialty-latexdependence on imported products. form a joint venture businesses in North America for a fair- August 10, 2009 — Saudi Basic Industries value consideration of $50 million (2009...And a FEED contract by VCNG Corp. (SABIC; Riyadh, Saudi Arabia; www. estimated revenue for these businessesAugust 5, 2009 — KBR has been awarded sabic.com) and Mitsubishi Rayon Co. (MRC; is approximately $450 million).The pro-a contract by Verkhnechonskneftegas Tokyo; www.mrc.co.jp) have signed a letter of ceeds from the sale are accretive to Dow’s(VCNG) to provide front-end engineering intent (LoI) to establish a 50/50 joint venture shareholders and will be used for furtherand design (FEED) services for the VC FFD (JV) in Saudi Arabia.The LoI outlines the prin- deleveraging.The selection of Arkema asProject located in the Eastern Siberia region cipal terms of the proposed $1-billion JV in- the buyer must be approved by the FTC,of Russia. KBR will provide FEED services for a cluding the structure, technology, marketing and the two companies will be shortly re-new, 140,000-bbl/d oil facility, which will be and feedstock supply, with startup targeted viewing the proposed transaction with FTCtied back, via a new 85-kilometer pipeline, for 2013. Under the LoI, the JV will utilize the authorities.The deal is expected to close into the existing East Siberian Pacific Ocean ethylene-based Alpha process commercial- the 4th quarter of 2009.(ESPO) pipeline. ized by Lucite (a wholly owned subsidiary of MRC) to manufacture methyl methacrylate Dow to divest ownership in Optimal GroupDiageo USVI enters contract for rum- (MMA) monomer, with a design capacity of of Companies to Petronasdistillery washwater-treatment unit 250,000 metric tons per year (m.t./yr).Also, July 31, 2009 — The Dow Chemical Co. (Dow;July 21, 2009 — Diageo USVI (London; www. the JV company will manufacture polym- Midland Michigan; www.dow.com) anddiageo.com) has awarded a contract ethyl methacrylate (PMMA), with a design Petroliam Nasional Berhad (Petronas) haveto Veolia Water Solutions & Technologies capacity of 30,000 m.t./yr. announced that they have reached an(VWS; Saint Maurice, France; www.veolia- agreement for Dow’s Union Carbide Corp.waterst.com) for the turnkey design, build, Oxea completes acquisition of subsidiary to sell its entire shares of owner-and startup of the washwater treatment production plant in the Netherlands ship in the Optimal Group of Companiesplant that will support its planned Captain August 3, 2009 — Oxea (Oberhausen, (Optimal) to Petronas for $660 million. Pet-Morgan rum distillery on St. Croix, U.S.Virgin Germany; www.oxea-chemicals.com), the ronas would fund this acquisition throughIslands.The washwater treatment plant will global chemical company, has complet- internally generated funds.The transaction,be located in the western half of the 25-acre ed its acquisition of assets of the Amster- subject to customary conditions and ap-building site at the St. Croix Renaissance dam Esters Plant from ExxonMobil Chemi- provals, is expected to close by the end ofIndustrial Park.VWS, through its U.S. busi- cal Holland B.V. Details of the transaction the 3rd quarter of 2009. ■nesses Biothane and N.A. Water Systems, will were not disclosed. Dorothy Lozowski For additional news as it develops, please visit www.che.comSeptember 2009; VOL. 116; NO. 9Chemical 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. Periodicalspostage paid at Rockville, MD and additional mailing offices. Postmaster: Send address changes to Chemical Engineering, Fulfillment Manager, P.O. Box 3588, Northbrook,IL 60065-3588. Phone: 847-564-9290, Fax: 847-564-9453, email: clientservices@che.com. Change of address, two to eight week notice requested. For information regardingarticle reprints, please contact Angie Van Gorder at angie.vangorder@theygsgroup.com. Contents may not be reproduced in any form without written permission. Publica-tions Mail Product Sales Agreement No. PM40063731. Return undeliverable Canadian Addresses to: P.O. Box 1632, Windsor, ON N9A7C9.FOR MORE ECONOMIC INDICATORS, SEE NExT PAGE ChemiCal engineering www.Che.Com September 2009 63
    • Economic Indicators 2009 2008 dOwnLOAd ThE cepci TwO wEEkS SOOnER AT www.che.com/pciCHEMICAL ENGINEERING PLANT COST INDEX (CEPCI) 650 (1957-59 = 100) Jun. 09 May. 09 Jun. 08 Prelim. Final Final Annual Index:CE Index 508.9 509.1 597.1 2001 = 394.3 600Equipment 596.8 596.8 729.7 Heat exchangers & tanks 529.9 529.9 738.2 2002 = 395.6 Process machinery 583.0 583.0 658.7 2003 = 402.0 550 Pipe, valves & fittings 748.1 748.1 858.8 2004 = 444.2 Process instruments 388.9 389.0 452.8 Pumps & compressors 896.7 896.7 865.9 2005 = 468.2 500 Electrical equipment 458.9 458.9 459.0 2006 = 499.6 Structural supports & misc 602.4 602.4 793.1 450Construction labor 326.0 326.6 319.4 2007 = 525.4Buildings 485.2 485.4 515.3 2008 = 575.4Engineering & supervision 347.3 347.9 353.9 400 J F M A M J J A S O N DStarting with the April 2007 Final numbers, several of the data series for labor and compressors have beenconverted 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) Jul. 09 = 89.8 Jun. 09 = 89.1 May. 09 = 89.1 Jul. 08 = 106.1 CPI value of output, $ billions Jun. 09 = 1,480.4 May. 09 = 1,424.8 Apr. 09 = 1,394.1 Jun. 08 = 2,073.9 CPI operating rate, % Jul. 09 = 66.0 Jun. 09 = 65.4 May. 09 = 65.2 Jul. 08 = 77.7 Producer prices, industrial chemicals (1982 = 100) Jul. 09 = 234.6 Jun. 09 = 229.8 May. 09 = 218.8 Jul. 08 = 315.6 Industrial Production in Manufacturing (2002=100)* Jul. 09 = 94.8 Jun. 09 = 93.9 May. 09 = 94.4 Jul. 08 = 110.8 Hourly earnings index, chemical & allied products (1992 = 100) Jul. 09 = 149.1 Jun. 09 = 147.6 May. 09 = 147.2 Jul. 08 = 141.7 Productivity index, chemicals & allied products (1992 = 100) Jul. 09 = 128.5 Jun. 09 = 128.6 May. 09 = 128.8 Jul. 08 = 130.6 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)M & S IndEx 2nd Q 2009 1,462.9 1st Q 2009 1,477.7 4th Q 2008 1,487.2 3rd Q 2008 1,469.5 2nd Q 2008 1,431.7 1485 1470 F inal estimates for May and preliminary esti- mates for the June CEPCIProcess industries, average 1,534.2 1,553.2 1,561.2 1,538.2 1,491.7 Cement 1,532.5 1,551.1 1,553.4 1,522.2 1,473.5 indicate that there was 1455 Chemicals 1,504.8 1,523.8 1,533.7 1,511.5 1,464.8 a very slight decrease in Clay products 1,512.9 1,526.4 1,524.4 1,495.6 1,453.5 1440 equipment prices from Glass 1,420.1 1,439.8 1,448.1 1,432.4 1,385.1 1425 month to month. Mean- Paint 1,535.9 1,554.1 1,564.2 1,543.9 1,494.8 while, estimates for the Paper 1,435.6 1,453.3 1,462.9 1,443.1 1,400.0 1410 May, June (both revised) Petroleum products 1,643.5 1,663.6 1,668.9 1,644.4 1,594.4 1395 and July operating rates Rubber 1,581.1 1,600.3 1,604.6 1,575.6 1,537.5 confirm that slowly butRelated industries 1380 Electrical power 1,394.7 1,425.0 1,454.2 1,454.4 1,412.8 surely, shuttered facilities Mining, milling 1,562.9 1,573.0 1,567.5 1,546.2 1,498.9 1365 and process units are com- Refrigeration 1,789.0 1,807.3 1,818.1 1,793.1 1,741.4 ing back on-stream, and 1350 Steam power 1,490.8 1,509.3 1,521.9 1,499.3 1,453.2 widespread capacity cor- 1335 rections are behind us. Annual Index: Visit www.che.com/pci 1320 2001 = 1,093.9 2003 = 1,123.6 2005 = 1,244.5 2007 = 1,373.3 1st 2nd 3rd 4th for more on capital cost 2002 = 1,104.2 2004 = 1,178.5 2006 = 1,302.3 2008 = 1,449.3 Quarter trends and methodology. ■64 ChemiCal engineering www.Che.Com September 2009
    • (Advertisement) PROCESS INSIGHT Selecting the Best Solvent for Gas TreatingSelecting the best amine/solvent for gas treating is not a trivial task. Tertiary AminesThere are a number of amines available to remove contaminants such A tertiary amine such as MDEA is often used to selectively removeas CO2, H2S and organic sulfur compounds from sour gas streams. H2S, especially for cases with a high CO2 to H2S ratio in the sour gas.The most commonly used amines are methanolamine (MEA), One benefit of selective absorption of H2S is a Claus feed rich in H2S .diethanolamine (DEA), and methyldiethanolamine (MDEA). Other MDEA can remove H2S to 4 ppm while maintaining 2% or less CO2 inamines include diglycolamine® (DGA), diisopropanolamine (DIPA), the treated gas using relatively less energy for regeneration than thatand triethanolamine (TEA). Mixtures of amines can also be used to for DEA. Higher weight percent amine and less CO2 absorbed resultscustomize or optimize the acid gas recovery. Temperature, pressure, in lower circulation rates as well. Typical solution strengths are 40-50sour gas composition, and purity requirements for the treated gas weight % with a maximum rich loading of 0.55 mole/mole. Becausemust all be considered when choosing the most appropriate amine for MDEA is not prone to degradation, corrosion is low and a reclaimera given application. is unnecessary. Operating pressure can range from atmospheric, typical of tail gas treating units, to over 1,000 psia. Mixed Solvents In certain situations, the solvent can be “customized” to optimize the sweetening process. For example, adding a primary or secondary amine to MDEA can increase the rate of CO2 absorption without compromising the advantages of MDEA. Another less obvious application is adding MDEA to an existing DEA unit to increase the effective weight % amine to absorb more acid gas without increasing circulation rate or reboiler duty. Many plants utilize a mixture of amine with physical solvents. SULFINOL is a licensed product from Shell Oil Products that combines an amine with a physical solvent. Advantages of this solvent are increased mercaptan pickup, lower regeneration energy, and selectivity to H2S.Primary Amines Choosing the Best AlternativeThe primary amine MEA removes both CO2 and H2S from sour gas Given the wide variety of gas treatingand is effective at low pressure. Depending on the conditions, MEA options, a process simulator that cancan remove H2S to less than 4 ppmv while removing CO2 to less than accurately predict sweetening results is a100 ppmv. MEA systems generally require a reclaimer to remove necessity when attempting to determinedegraded products from circulation. Typical solution strength ranges the best option. ProMax® has been proven to accurately predict results for numerousfrom 10 to 20 weight % with a maximum rich loading of 0.35 mole process schemes. Additionally, ProMaxacid gas/mole MEA. DGA® is another primary amine that removes can utilize a scenario tool to performCO2, H2S, COS, and mercaptans. Typical solution strengths are 50- feasibility studies. The scenario tool may60 weight %, which result in lower circulation rates and less energy be used to systematically vary selectedrequired for stripping as compared with MEA. DGA also requires parameters in an effort to determine thereclaiming to remove the degradation products. optimum operating conditions and the appropriate solvent. TheseSecondary Amines studies can determine rich loading, reboiler duty, acid gas content ofThe secondary amine DEA removes both CO2 and H2S but generally the sweet gas, amine losses, required circulation rate, type of aminerequires higher pressure than MEA to meet overhead specifications. or physical solvent, weight percent of amine, and other parameters.Because DEA is a weaker amine than MEA, it requires less energy for ProMax can model virtually any flow process or configurationstripping. Typical solution strength ranges from 25 to 35 weight % with including multiple columns, liquid hydrocarbon treating, and split flowa maximum rich loading of 0.35 mole/mole. DIPA is a secondary amine processes. In addition, ProMax can accurately model caustic treatingthat exhibits some selectivity for H2S although it is not as pronounced applications as well as physical solvent sweetening with solvents suchas for tertiary amines. DIPA also removes COS. Solutions are low as Coastal AGR®, methanol, and NMP. For more information aboutin corrosion and require relatively low energy for regeneration. The ProMax and its ability to determine the appropriate solvent for a givenmost common applications for DIPA are in the ADIP® and SULFINOL® set of conditions, contact Bryan Research & Engineering.processes. Bryan Research & Engineering, Inc. P.O. Box 4747 • Bryan, Texas USA • 77805 979-776-5220 • www.bre.com • sales@bre.com Circle 02 on p. 62 or go to adlinks.che.com/23018-02
    • Badger Meter RESEARCH CONTROL® Badger Meter’s RESEARCH CONTROL Valves have beenLow and Micro Flow Valves ® ® ® http://www.badgermeter.com/Industrial/Valve-Products.aspx 800-364-9876 Circle 03 on p. 62 or go to adlinks.che.com/23018-03