Cost and energy efficiency assessment of odour abatement systems 7_1_15 Action 15

Cost and energy efficiency assessment of odour abatement
systems
Carbon footprint of abatement systems
Dispersion model of odours in a case study
Authors: Meehanite Technology Ltd and AX Consulting Ltd
Date: 15.9.2014

Odorless casting
Action 15 Reliable, cost and energy efficient odour abatement system
2
Table of Contents
Table of Contents.................................................................................................................................2
Appendixes...........................................................................................................................................3
Abbreviations used...............................................................................................................................4
Pilot foundries......................................................................................................................................5
1 Aim of the report..........................................................................................................................6
2 Pilot studies of abatement systems...............................................................................................6
2.1 Content of pilot studies..........................................................................................................6
2.2 Piloted test description ........................................................................................................10
2.3 Results of abatement systems..............................................................................................11
2.3.1 RTO oxidation system .................................................................................................12
2.3.2 Biofilter system............................................................................................................14
2.3.3 Adsorption system........................................................................................................17
2.3.4 Ignition system.............................................................................................................18
3 Cost analysis, results and conclusion.........................................................................................20
3.1 RTO oxidation system.........................................................................................................21
3.2 Biofilter system ...................................................................................................................21
3.3 Adsorption system...............................................................................................................22
3.4 Ignition system ....................................................................................................................22
3.5 Carbon footprint of abatement systems...............................................................................23
3.6 Conclusion, recommendation..............................................................................................24
4 Dispersion model of odours in the case study of iron foundry Finland.....................................28

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Appendixes
APPENDIX 1 Mass and energy flow calculation of thermal regenerative incinerator
system for a Finnish iron foundry
APPENDIX 2 Cost calculations of HAPs abatement systems for a Finnish iron foundry
(biofilter, thermal oxidation and adsorption)
APPENDIX 3 Mass and energy flow calculation of thermal regenerative incinerator
system for a Finnish cupola furnace melting
APPENDIX 4 Cost calculations of HAPs abatement systems for a Finnish cupola furnace
melting (biofilter, thermal oxidation and adsorption)
APPENDIX 5 Schematic diagram of Nederman adsorption design
APPENDIX 6 Schematic diagram of CTP regenerative thermal oxidation incinerator
APPENDIX 7 Schematic diagram of Reinluft biofilter
APPENDIX 8 Description of adsorption chemical used in Nederman abatement system
APPENDIX 9 Dispersion model of odours in a case study in Finland, Total odour
emissions without abatement systems
APPENDIX 10 Dispersion model of odours in a case study in Finland, Odour emissions
with abatement system Biofilter
APPENDIX 11 Dispersion model of odours in a case study in Finland, Odour emissions
with abatement system RTO

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Abbreviations used
Adsorption Adsorption is a physical phenomenon in which gaseous component, called
adsorbate, are removed from gas stream by adhering to the surface of a solid
material, and called adsorbent.
Amine Amine gases that are used to harden cores by gas injection
AX AX Consulting Ltd www.ax.fi, project partner
BAT Best available technology
Biofilter Biological cleaning method to abate odorous VOC gases and odour
compounds by micro-organisms
BTEX benzene, toluene, ethylbenzene, xylene
CO Carbon monoxide
Concentrator An additional pre-treatment method based on adsorption and desorption of
odourus VOC gas to increase the exhaust air concentration
CTP Chemisch thermische Prozesstechnik GmbH
EN European Standard
EPA Environmental Protection Agency
http://www.ctp-airpollutioncontrol.com/, project partner
FID Flame ionization detector
HAP Hazardous air pollutant
hardener = Hardeners are used to harden sand moulds to stand melt metal pouring into
bonding agent mould
IfG Insitut für Giessereitechnik gGmbH www.ifg-net.de, project partner
Meehanite Meehanite Technology Ltd, project coordinator
Nederman Nederman Filtration GmbH www.nederman.com
NOx generic term for the mono-nitrogen oxides NO and NO2
(nitric oxide and nitrogen dioxide).
ou odour unit (ouE/mg3
)
ppm parts per million
Reinluft Reinluft Umwelttechnik Ingenieurgesellschaft mbH www.reinluft.de,
project partner
RCO Regenerative catalytic oxidation
Rotor rotating concentrator, wheel type
RTO Regenerative thermal oxidation
SCR selective catalytic reduction
SFS Finnish Standards Association
SWECAST Swedish foundry branch’s institute for research, development, education and
training http://www.swerea.se/
TVOC Total volatile organic compounds, Concentration of TVOCs are presented as
total mass of different compounds (gVOC/m3
)
TOC Total organic carbon, Concentration of TOC presented as is presented as total
mass of carbon in compounds (gC/m3
)
US United States
VOC Volatile organic compounds

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Pilot foundries
Iron foundry in Sweden = Swedish iron foundry
Steel foundry (nr. 1) in Germany = German steel foundry (nr. 1)
Steel foundry (nr. 2) in Germany = German steel foundry (nr. 2)
Aluminium foundry in Sweden = Swedish aluminium foundry
Iron foundry in Germany = German iron foundry
Steel foundry in Finland = Finnish steel foundry
Aluminium foundry in the Netherlands = Netherlands aluminium foundry
Aluminium foundry in Austria = Austrian aluminium foundry
Cupola furnace iron foundry in Finland = Finnish cupola furnace iron foundry
Iron foundry in Finland = Finnish iron foundry

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1 Aim of the report
The aim of this report is to provide a summary of experience gathered during the
piloting periods of the different odourless abatement systems and to describe the
performance of foundry odour control. The report includes the description of the
abatement systems, the feasibility, the performance and the carbon footprint of
abatement systems. In addition to the report summaries, technical possibilities of
foundry odour control and the cost assessment of control action will be presented in
total costs and nominal prices (€/ton, €/a).
2 Pilot studies of abatement systems
In this chapter, the outcomes of four different piloted cases will be explained. The first
case is the regenerative thermal oxidation system and the summary conclusion report
of RTO (case 1) is explained in chapter 2.1.1. The second case is the biofilter systems
and the summary conclusion report of biofilter (case 2) is explained in chapter 2.1.2.
The third case is the adsorption system and it outcome conclusion is explained in
chapter 2.1.3.The fourth case is the ignition system and it conclusion is explained in
chapter 2.1.4. Summary table of all pilot studies can be seen in Table 1.
2.1 Content of pilot studies
Case 1: Regenerative thermal and catalyst oxidation and adsorption systems
In VOCless pulping EU Life project (LIFE09/ENV/FI/000568), we have had good
VOC emission abatement results with regenerative thermal oxidation incinerator.
The material properties for the RCO, RTO technologies were already studied in this
previous EU Life VOCless pulping project. Figure of schematic chart of RCO and
RTO systems can be seen in Figure 1. The specific pilot conditions for RTO odour
abatement technique were more or less already defined. The outcomes of the RTO
pilot results were promising in VOCless pulping project, and this is why Case 1 was
selected as one of the cases to reduce other hazardous air pollutant and odours.
The performance and testing applicability of regenerative catalytic oxidation (RCO)
and regenerative thermal oxidation (RTO) were pre-tested to study the efficiency
capacity for odour and hazardous emissions removal. Catalyst feasibility for odour
abatement was pre-tested in a Finnish steel foundry. The results gained from the
pre-piloting determined the BAT RCO and RTO abatement systems for different
foundries. The performance and feasibility of regenerative thermal oxidation CTP
(RTO) odour abatement system was tested in a Finnish iron foundry. The RTO pilot
methods were developed and manufactured by CTP.

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Figure 1. Schematic figure of RCO and RTO systems
Case 2: Biofilter technology system
The biofiltration is due to its natural principle the most energy-saving waste air
treatment technology. The method consists of a biological process which is based on
the activity of microorganisms-comparable with biological waste water treatment
plants. Therefore, the operating pressure and temperature are corresponding to
ambient conditions. The elimination of pollutants is carried out by microorganisms
inside the biofilter. This means that there is no need of additional energy. As the used
filter material is based on renewable resources (wood, compost, bark, etc.) the whole
process is CO2-neutral. All in all, the tests have shown that biofiltration is a suitable
and cost-effective technology for the waste air treatment in foundries.
This case was chosen to be part of Odorless casting project because it has proven good
VOC abatement capacity in the VOCless pulping previous EU Life project
(LIFE09/ENV/FI/000568).
The performance and feasibility of the two biofilter odour abatement systems were
tested in two German steel foundries. Schematic figure of the biofilter pilot system
can be seen in Figure 2. Both of the biofilter pilot methods were developed and
manufactured by Reinluft. The measurements were carried out by Reinluft.

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Figure 2. Schematic figure of biofilter system
Case 3: Adsorption filter system
Adsorption filtration system is based in a way on a returned adsorption material
feeding system where dust or a granulated type additive is sprayed in the exhaust flow
and thus spread on the bag filter surface to adsorb gas components with big molecules
from the off-gas. The existing filter plant already used for the purpose of dedusting the
pouring line exhaust stream can be applied. The additive adsorbent is sprayed and thus
mixed in the uncleaned raw gas.
The adsorption materials applied can be quite typical ones because of high molecular
weight substances from the degradation process on moulding lines. Activated
charcoal, limestone, brown coal, and zeolite materials can be used. The adsorption
reaction takes place in the additive layer on the filter bag material where adsorbent
lays between cleaning pulse periods. The reaction time is sufficient using a normal
bag filter loading factor of 1 m3
/m2
min corresponding to 17 mm/s face velocity
offering sufficient delay time with the layer thickness of 2 mm. By using recirculation
of once filtered adsorbent, one can easily build a sufficient adsorbent layer and, thus,
saving material cost. A recirculation rate as high as 9/10 can be applied. The pilot test
was carried out in a steel foundry. Nederman was responsible for the design and
implementation of the pilot tests and IfG carried out the efficiency measurements of
the adsorption pilot plant. Adorption system of Nederman technology can be seen in
Figure 3.

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Figure 3. Piloted adsorption system is consisting of bag filter and adsorbant
Case 4: Ignition system
IfG has developed a simple and robust system to elongate the burning phase of gas
emission of a cast flask. The invention uses the fact that the pouring gas only at the
beginning of the cooling of the cast is energetic (“fat”) enough to sustain an
auto-oxidative burning process. Most of the time, the gases are being emitted from the
mould into the surrounding atmosphere without generating a flame. By this, CO2 and
water are not the main reaction products but hydrocarbons, phenols and other
odourants. IfG found out that one has not to fatten up the pouring gas to improve the
burning but to introduce the ignition energy into the premixed gas. Doing so, the
burning can be elongated from less than 5 % to about 50 % of the whole emission
time. As a consequence, the odour emissions are remarkably diminished – more than
90% were measured under suitable conditions. The reduction is not related linearly to
the burning time as the gas emissions naturally decrease – described by an exponential
function.
The performance and feasibility of ignition odour abatement system pilot test was
carried out at a cupola and induction melted green sand moulded iron foundry. The
piloting period differs from the other systems. The assembly of the ignition system
was done by research partner staff (IfG) only. The foundry staff does not know the
detailed instructions of the ignition system. The test ignition system was assembled
and reassembled on each flask during production in a continuous row. This means that
ignition piloting took place 2-3 times in a period of one day. The cleaning efficiency,
odour balance effect and feasibility tests of the system were investigated
simultaneously during these periods. The pilot test (schematic figure can be seen in

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Figure 4) design and implementation and efficiency measurements were carried out by
IfG.
Figure 4. Schematic figure of ignition system
2.2 Piloted test description
The efficient functioning of the four pilot tests was assured by continuous monitoring,
weekly visits, and performance measurements. The technical monitoring and
performance measurements were carried out by AX Consulting, IfG, Nederman,
Reinluft, CTP and Meehanite.
The piloting periods of pilot plants were lasted from 4 weeks up to 8 weeks. In
addition to TOC, VOC and odours, the following parameters were recorded with the
help of continuous measurements: raw and clean gas flow rates, temperatures,
humidity and air flows of the industry units. Continuous monitoring of selected
parameters took place via modem connection to a PC based office recorder. In each
visits the temperature of the air and humidity of industry units, the odour
measurements samples, and pilot clean and raw gas flow were also measured and
recorded. The correct run modes of pilot plants were controlled in order to gain valid
comparable data.
Additionally, standard short-term emission measurements and other control measures
were carried out during the piloting period to insure that the cleaning efficiency of the
odour abatement systems will stay stable. These measurements periods can be found
in the measurement reports of each foundry systems in relevant Action 11-14 reports.
The measurements of the odour and odorous VOC cleaning and thermal efficiency
levels revealed that the pilot plants were functional and stable (see Table 2-5).
The outcome of the four cases odour and hazardous emission cleaning techniques will
be presented in chapter 2.1.
The odorous emission was carried out in compliance with the EN 13725:2003
standard. The TVOC concentration measurements were carried in continuous FID
measurements according to the EN 13526 and in mass concentration definition
according to the US/EPA method 25. The air flow measurements were carried out
according to the SFS 5512 standard.
Battery

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Table 1. Tested abatement systems in pilot plants in time order. The year indicates
when the measurment was carried out
Odour balance
measurement of foundries
Pilot plant installations for different cleaning technologies
Pilot foundries Partner responsible Odour panel Chemical
analyses
RCO RTO C+RTO Biofilter Ignition Adsorption
Finnish Steel AX/Meehanite 2013 2013 2012*
*pre-tested
Finnish Iron AX/Meehanite 2013 2013 2013 2013 2013
German Steel IfG 2012 2012 2012 2012
German Steel Reinluft x x 2014
German Iron IfG 2013 2013 2013
Austrian
Aluminium
CTP/IfG x x 2012
Nederland
Aluminium
IfG 2014 2014
Swedish Iron AX,Swerea, Meehanite 2012 2012
Swedish
Aluminium
AX,Swerea, Meehanite 2012 2012
Finnish Cupola
furnace
AX, Meehanite (odour
balance for
cupla melting)
2014 2014
Total 7 odour emission balances
+ cupola
3 pilot tests + 1 pre-test 2 pilot
tests
1 pilot
test
1 pilot test
2.3 Results of abatement systems
The results and reports of the piloting sites are presented in Action 11-14.
The abatement techniques are explained in Action 15 Feasibility Study of Techniques
report. In this report, only conclusions and recommendations will be gathered for the
four odour abatement techniques.
Adsorption and ignition odour and hazardous emission technologies could not reach
as high cleaning efficiency as RTO and biofilter odour technologies during the test
periods. However, odour abatement efficiency was successful enough in the ignition
system to encourage furthers improvement of the technology. It is expected that the
ignition system will be further developed to improve hazardous emissions cleaning
efficiency (more about the results in chapter 2.1.4) e.g. existence of continuous flame
during all cooling stages.
Adsorption abatement efficiency was low possibly due to the low raw gas
concentration. Higher concentration improves removal efficiency as previous testing
results have shown (more about the results in chapter 2.1.3).

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Biofilter could reach about 85% sufficient odour cleaning efficiency with a pre-treated
scrubber installation. This system is a proving abatement technology in low TVOC
concentration sources (more about results in chapter 2.1.2).
The cleaning efficiency was the highest in the case of regenerative thermal oxidation.
The small pilot thermal oxidation ignition system in the pilot studies was working in a
71-95% of odour and a 91-99.5% of TVOC efficiency level. The full size RTO system
with rotor concentrator installation and the 3-bed RTO showed an effective best
available technology (BAT) solution (more about the results in chapter 2.1.1) with the
cleaning efficiency of 99.5 % and the common full size 2-bed RTO reaches efficiency
of 97-98 %.
The results of all the offers and simulations for BATs odour and hazardous air
pollutant emission controls are described in this report (Chapter 2.1.1-2.1.4). The
results illustrate the running cost of these installations (RTO oxidation, biofilter,
adsorption, ignition) giving reliable cost estimations for abatement cases in real use.
The accuracy of the results can be considered accurate enough (+/- 10 %) because of
the existence of normal running conditions for these cleaning technology applications
in the pilot tests.
2.3.1 RTO oxidation system
Regenerative catalytic and thermal oxidation (RCO, RTO) systems were pre-piloted to
abate TVOC emissions at a Finnish steel foundry (2012). The outcome of pre-piloting
showed that within the accuracy of the measurement, the catalytic activity did not
suffer during the pilot test period. This shows that it is possible to protect the catalyst
from catalyst poisons (aging phenomena) and fouling in this application by use of a
dust filter and selection of the right catalyst. It is recommended considering using
regenerative catalytic oxidization abatement system as well, but right conditions
needed to be defined with care in order to protect the catalyst system.
Regenerative thermal oxidation (RTO) system was tested to abate odour and TVOC
emissions as full size at an Austrian aluminium foundry, and a Finnish iron foundry.
Table 2 illustrates the overall cleaning and thermal efficiency of thermal oxidation
system at both sites.
The pilot thermal oxidation abatement technology reached a cleaning efficiency of
odour between 90 - 95 %. This level seems to be high enough in the case of present
odour emission levels in exhaust gases. Odour concentrations of raw gases (before
thermal oxidation) were on the level of 512-4340 ouE/m³. The odour concentrations
after thermal oxidation decreased to 51-217 ouE/m³ at the both pilot plants. This
cleaning performance provides sufficient guidelines for emission limit values that will
guide decision makers set threshold limit in the near future to improve health of
foundry staff and neighbors of foundry surroundings.
In the case of a Finnish iron foundry, the total odour cleaning efficiency remained less
efficient because of the system design was a prototype. Similar 3-bed RTO cleaning
system was offered for a Finnish iron foundry by CTP (see Figure 5) and this system
has a 95% of odour cleaning efficiency. The PI-diagram is in Appendix 6. An initial
concentrator rotor before the thermal oxidation chamber improves the efficiency
roughly with an additional 5-10 %.

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In the case of full size aluminium foundry, the odour abatement efficiency was 95%
and 99.5 % of TVOC compounds. The full size plant shows that CTP´s technology
can be applied to successfully remove odour particles from the foundry industry.
The thermal efficiency of pilot thermal incinerator was 95 - 97 % which is efficient
enough. In the pilot plant this feature was not in focus. The thermal efficiency depends
usually on the optimization of the heat recovery construction (more regenerative
mass). The higher efficiency is needed, the higher investment fan power is required.
The higher the thermal efficiency, the less heat energy is consumed in the oxidation
process. The optimal area is between 93-97 %. The thermal incinerator consumes
more energy (operating chamber temperature usually 850 o
C) than catalyst
incinerators (250-350 o
C).
The preheating of the raw gas is performed by a heat exchanger. In CTP pilot unit the
regenerative heat exchanger is made of ceramic honey-comb cubes so that wholes are
forming similar structure as used in ceramic catalyzers. This structure has very
effective heat transfer power offering efficiency up to 95 % depending of the whole
size and gas velocity. This type of heat exchanger could reach in our pilot tests
autothermic operation point of as low as 0.91 gVOC/Nm3
. Autothermic point is a
minimum VOC concentration where incineration unit doesn’t need any additional
energy to keep the oxidation temperature on the needed level.
Continuous monitoring of process parameters and emission concentrations and
cleaning of the abatement system need to be ensured.
The pilot test approved the applicability of CTP RTO-SCR cleaning system for
foundries. The SCR phase was investigated because of high N-compound contents of
amine gases in cold box core production. The NOx reduction of almost 100 % was
achieved and NOx concentration stayed at the low level of 2.03 mg/m3
(1 ppm).
Table 2. Cleaning efficiency and thermal efficiency of piloted foundry
regenerative thermal oxidation 3-bed and 2-bed systems
Pilot site
TVOC cleaning
efficiency, %
Odour cleaning
efficiency, %
Thermal
efficiency, %
Austrian Aluminium foundry
with phenol resin and amine
hardener (3-bed)
99.5 95 95
Finnish Iron foundry
with phenol moulding
phenol+amine cores (2-bed)
95
(90…98,5)
>90
(71.5…96)*
97
(90…98.5)
*Odour samples have been neglected because of high discrepancy in typical results.
Other case measurements are evaluated as more reliable ones, instead of the piloted
iron foundry measurement results.

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Figure 5. Full size 3-bed CTP RTO system
2.3.2 Biofilter system
The function of biofilter is based on micro-organisms (bacteria), which is laid on
organic carrier material (bed material) like wood, chips, peat, bark etc. Biofiltration
consists of a sorption phase of pollutants on a carrier surface and a subsequent
degradation phase by micro-organisms, which are settled in an aqueous phase on the
carrier substance. Unlike bioscrubbing, biofiltration is performed in two
simultaneous steps (sorption and degradation). While inlet gas is led to flow slowly
through the bed, micro-organism has sufficient time to catch odorous
VOC-molecules and convert it to water and carbon dioxide. Reason of slow flow is
e.g. methane is one of the inert gas molecules that bacteria cannot destruct easily.
Organic micro fauna does not produce methane itself.
The biofilter pilots were carried out in order to find the most cost and odour efficient
technique / techniques for the exhaust gases for foundry industries.

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The overall TVOC elimination capacity of the biofilter showed an efficiency of 75 %
at an average filter space loading of 110 m³/(m³h) in a German steel foundry (nr. 1)
(2012). The odour reduction efficiency was 85% based on the results.
In spite of high area demand of biofilter, it can be constructed like a tower, see full
size biofilter construction in Figure 6. The PI-diagram of biofilter system is in
Appendix 7.
The overall elimination capacity of the biofilter showed an efficiency of 52 % at an
average filter space loading of 90 m³/(m³h) and the odour reduction efficiency is
calculated to 95% based on a German steel foundry (nr. 2) (2013) results. The overall
odorous VOC elimination capacity was not as high as expected, but this is due to the
high amount of aromatic compounds in the degradation products of cold-box moulds.
Odorous VOC concentrations of raw gas (before biofilter) were on an average
74 mgVOC/m3
in a German steel foundry (nr. 2) (2013), and on an average 9.5
mgVOC/m3
in a German steel foundry (nr. 1) (2012) raw gas. VOC concentrations
after biofilter plant in a steel foundry (nr. 1) (2012) were 11.6 mgVOC/m3
(corresponding to 9.5 mgC/m3
). This was set up as the target emission level
correlated with odour emission in the project. The steel foundry cases resulted to a
higher raw exhaust concentration. This requires a better cleaning efficiency, but pilot
studies showed that most odours can be degraded and removed biologically with
high level of efficiency in steel foundries. Summary of biofilter cleaning efficiency
can be seen from Table 3.
Table 3. Cleaning efficiency of piloted biofilter systems
Pilot site
Odorous VOC
cleaning
efficiency, %
Odour
cleaning
efficiency, %
German Steel foundry (nr. 1) in 2012:
Induction melting, automatic green sand molding
furan sand cores
75 85
German Steel foundry (nr. 2) in 2013:
Induction melting, automatic green sand molding
52
(36-68)
95
(93-98)

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Figure 6. Biofilter full size plant at a German steel foundry

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2.3.3 Adsorption system
The pilot system works with the adsorption of the odours in the surface of active
materials like active carbon or other suitable adsorbents, see mineral Minisorb
analysis in Appendix 8. The powdery additive is fed with a variable dosing system
continuously in the raw gas. The adsorption takes place during the flow of the
additive in the raw gas up to the filter media. At the filter media, consisting of needle
felt, there is a growing dust cake that is online cleaned off.
The cleaning system is a pulse jet system that works online during the continuous
filtration process. For better utilization of the additive, it is recirculated. This means
the filter is cleaned of and 9 from 10 parts of the dust is brought back in the raw gas
for further reaction and for a better usage of adsorbant. The smaller part is brought to
the waste container. Without recirculation only 10% of the additive is used. With
recirculation it is increased to above 90%. A higher recirculation ratio of for example
20 to 1 does not make sense, since in large technical plants the material flows would
be very high. See the pilot plant tested in Figure 7 and the process and
instrumentation diagram in Appendix 5.
The cleaning odour efficiency was very low (see Table 4), because of the very low
raw gas concentration. With higher concentration, the removal efficiency would
increase significantly, because the clean gas values stay almost in the measured level
independent of the raw gas. This effect could be regarded as normal and has proven
normally in applications with dry sorption of raw gases.
Table 4. Cleaning efficiency of piloted adsorption system
Pilot site
TVOC cleaning
efficiency, %
Odour cleaning
efficiency, %
German Steel foundry (nr. 1):
Induction melting, automatic green sand
molding, furan sand cores
46
(42-50)
37
(12-85)

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Figure 7. Full size adsorption system
2.3.4 Ignition system
The prototypal character of the IfG-ignition system has been widely described in
Action 15 Feasibility Study of Techniques report. New and innovative ignition frame
abatement system was designed to reduce odour and hazardous emissions in
foundries. Ignition frames were installed on the flasks in pouring line at once after
pouring occurred to reduce emissions right from the source of release. The odour
cleaning efficiency level was in a range of 65 %. During this method a spark initiates
an oxidation reaction of the harmful substances of the molded gases consisting HxCy
(hydrocarbons as well as hydrogen and CO). The sparks generate the ignition energy
which starts the oxidation reaction. Within this reaction the gases would be converted
into the products of water and carbon dioxide under exothermic conditions.

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The ignition pilot test was carried out at a green sand moulding steel foundry, in
Germany. The piloting period differs from the other systems. The assembly of the
ignition system was done by research partner staff (IfG) only. The test ignition
system was assembled and reassembled on each flask during production in a
continuous row. The cleaning efficiency, odour balance effect and feasibility tests of
the system were investigated simultaneously during test periods. The ignition system
is presented in Figure 8. The pilot test design and implementation and efficiency
measurements were carried out by IfG.
Results of pilot ignition system showed an overall ineffective TVOC and odour
eliminating results due to early stage of prototype development (see Table 5) but a
significant conversion of hazardous emission compounds, especially the
concentration of benzene was reduced on average of 50 % from the original
emission. The CO concentration was likewise reduced by approximately 40 % with
the aid of the pilot system. In the reality the ignition system cannot keep up the flame
in the concentration under LEL concentration. This means the “blue CO flame” of
the cooling flasks will be extinct in one-two hours after pouring which roughly
corresponds not more than half HAPs emissions during the all cooling period
(referring to emissions measurement of a closed flask in a Finnish iron foundry).
Thus only 25 % of odour emissions can be abated by the ignition systems of IfG
type.
Table 5. Cleaning efficiency of piloted ignition system
Pilot site
Odorous TVOC
cleaning
efficiency, %
Odour cleaning
efficiency, %
German Iron foundry:
induction melting, green sand
Cold box with acid scrubber cores
29 50
(34-54)
German Iron foundry: reality with 1-2
hours flaming period only in cooling
induction melting, green sand
Cold box with acid scrubber cores
15 25

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Figure 8. Pilot ignition system. The flames were in the exit of venting openings
where the high voltage ignition electrodes ignited flammable gases.
3 Cost analysis, results and conclusion
In the following conclusion the cost calculation data has been stated and compared
uniformly. The costs of the systems are based on several hundreds of inquiries, offers
and market outcomes and specified offers from CTP, Reinluft and Nederman. The
utility cost is based on actual Northern European price level. The cost, result and
conclusion are made with 3 different abatement systems (biofilter, RTO and
adsorption) for a Finnish iron foundry and the cupola furnace of a Finish iron
foundry (only for cupola emissions)
Each simulation case is defined by HAPs emission concentration and airflow.
Emission points, average air flows and HAP concentrations are presented in
Appendixes 1-4. The production takes place in 2 shifts, but in a Swedish iron
foundry in 3 shifts without weekend working. Nominal odour production can be seen
in Table 6 below.
Table 6. Nominal odour production (MouE/ton casting)
Pilot foundry
types
Odour
(ouE/m3
)
Airflow
(Nm3
/h)
ton/a
Nominal odour
emission /production
(MouE/ton casting)
Nm3
/h/ton
Steel (nr. 1) in
Germany
217 215 000 4 800 37* 45*
Steel in Finland 238 470 000 8 300 52 57
Aluminium in
Sweden
57 115 000 2 310 11 50
Iron in Germany 176 180 000 4 700 26* 38*
Iron in Finland 385 106 000 3 620 43 29
Iron in Sweden 2 366 1 700 000 20 000 1 172 86

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*results are based on assumed (not measured) ventilation rates only.
Note: not all of the pilot tests (6 out of 9) are included here due to non-available data.
Investment, energy and maintenance cost calculations based on the offers from CTP,
Reinluft and Nederman for sources of an induction melting hand moulding with
phenolic resin, cold box core. The cost calculation results of abatement systems can
be found in Appendix 2 and 4.
More detailed explanations of the RTO, Biofilter and adsorption outcomes for the
iron foundry Finland and cupola furnace melting process can be seen in Feasibility
Study of Techniques in Action 15 and emission measurement reports.
3.1 RTO oxidation system
According to the results of the RTO simulation (Appendix 1), the energy cost for a
Finnish iron foundry is about 112 000 €/a (Appendix 2). The energy cost of a thermal
oxidizer incinerator for the Cupola furnace melting was estimated to be 15 300 €/a
(Appendix 4) because of high presence of carbon monoxide. 99 % cleaning
efficiency and 96 % thermal efficiency of the thermal oxidizer incinerator has been
used in the RTO simulation following the data given by CTP offer in the iron
foundry. In cupola furnace melting process, 99.5 % cleaning efficiency and 96 %
thermal efficiency were used based on the CTP offer.
The annual cost of regenerative thermal oxidizer incinerator is based on calculations
from the investment cost, annual investment cost, maintenance and energy cost
(Appendix 2 and 4).
The annual total cost of the full-sized RTO + concentrator plant for iron foundry was
estimated to be 280 000 €/a (App. 2). The net cost annual destructed HAPs was
estimated to be 6 300 €/ton (App. 2). As a result of the cost of iron production would
increase by 77 €/ton (production net tons). It is 2.7 % increase of production cost.
The annual total cost of an RTO abatement system for the cupola furnace melting
process was estimated to be 69 000 €/a (App. 4). The net cost annual destructed
HAPs was estimated to be 39 500 €/ton (App. 4). The cost of iron production would
increase by 10 €/ton. It is 0.4 % increase of production cost.
3.2 Biofilter system
The annual costs of biofilter systems are based on calculations from the total and
annual investment, maintenance and energy costs according to the market prices of
the type of biofilters piloted and illustrated in Figure 6.
The annual total cost of the full-sized biofilter plant for the iron foundry was
estimated to be 170 000 €/a (App. 2). The net cost annual destructed HAPs was
estimated to be 4 500 €/ton (App. 2). As a result of this the cost of production of
iron would increase by 47 €/ton (production net tons). It is 1.6 % increase in
production cost.

Odorless casting
22
The annual total cost of a biofilter for the cupola furnace melting was estimated to be
45 000 €/a (App. 4). The net cost annual destructed HAPs was estimated to be
34 200 €/ton (App. 4). The cost of the production of iron would increase by 6 €/ton.
It is 0.3 % increase in production cost.
3.3 Adsorption system
The annual costs of adsorption systems are based on calculations from the total and
annual investment, maintenance and energy costs according to the market prices of
the type of adsorption piloted.
The annual total cost of the full-sized adsorption plant for induction melted hand
moulded phenolic resin cold box core iron foundry was estimated to be 688 000 €/a
(App. 2). The net cost annual destructed HAPs was estimated to be 20 000 €/ton
(App. 2). As a result of the cost of iron production would increase by 190 €/ton
(production netto tons). It is 7 % increase of production cost.
The annual total cost of an adsorption system for the Cupola furnace melting process
was estimated to be 105 000 €/a (App. 4). The net cost annual destructed HAPs was
estimated to be 79 600 €/ton (App. 4). The cost of iron production would increase
by 15 €/ton. It is 0.7 % increase of production cost.
Adsorption system odour reduction efficiency is regarded low because of low waste
gas concentration. In higher concentrations, the odour removal efficient would
increase as well. It can be concluded that the adsorption cleaning technology cannot
be considered as best available technology in the Odorless casting project due to low
odour cleaning efficiency. In principle, even with two sequential orders, the cleaning
efficiency of adsorption technology would not exceed 75 %. Therefore, costs are
considered to be out of range for foundry businesses.
3.4 Ignition system
Ignition system is not included in the cost calculation conclusion report but it is
interesting to give a summary cost calculation outcome of this system as well. This
will give a better overview for the interested parties and decision makers about all
the systems that were tested in the Odorless casting project
Ignition system cannot be regarded as a complete odour abatement system because it
does keep the oxidation flame on when flammable gases appear above ignition
concentration. That is the case in pouring and in the beginning at cooling stage
(1-2 hours after pouring). Still the cleaning efficiency is at maximum on the level of
50%.Ignition system tested can reach roughly to the cleaning rate of 25 -30 % of all
mould origin emissions during the pouring and cooling phases.
The annual total cost of the full-sized ignition plant for an iron foundry estimated to
be 69 200 €/a with the extra work of a fourth of man power and cost assumption of
ignition frames of middle size to be 2500 € each. As a result of the cost of the iron
production would increase by 16 €/ton (production net tons). It is 0.6 % increase of
production cost.

Odorless casting
23
3.5 Carbon footprint of abatement systems
The difference in CO2 equivalent emissions from abatement systems compared with
direct release can have two outcomes.
In case, the difference is negative. In this case, the negative value indicated there are
overall climate change benefits in abatement system compared with direct release of
the VOCs of these compounds in question.
In case the difference is positive. In this case, the positive value indicated there is
overall climate change harm or limitation in abatement system compared with direct
release of the VOCs of these compounds in question.
The default values of odorous VOCs spanning rage (GWP 100 year) between 0.1 and
10 for hydrocarbons if the odorous VOC of interest is not listed or referenced from
scientific data. The low value of spanning rage can be explained by the fact that most
of the VOCs atmospheric lifetimes are very short (from minutes to hours in most
cases) (Atkinson 2000 – Atmospheric Chemistry of VOCs & NOx).
Table 7. Carbon footprint GWP, 100 year of a Finnish iron foundry
Iron
foundry
RTO + ROTOR
ton CO2 eq. emission of
RTO system
RTO + TVOCs
Difference between RTO system and
direct TVOCs CO2 eq.
570 650 510
Biofilter
biofilter system
biofilter system and TVOCs
Difference between biofilter and
270 360 220
Adsorption
adsorption system
adsorption system + TVOCs
Difference between adsorption
system and direct TVOCs CO2 eq.
110 200 60
It can be seen from Table 7 that the difference in CO2 equivalent emissions from
abatement systems compared with direct release to the atmosphere indicated that all
cleaning systems would be more harmful to operate in order to clean odours and
odorous VOC emissions than allowing untreated emission directly to the atmosphere if
we consider environmental aspect and global warming.

Odorless casting
24
Table 8. Carbon footprint GWP, 100 year of cupola furnace in Finland
Cupola furnace
RTO
RTO system
ton CO2 eq. emission of RTO
+ TVOCs
Difference between RTO system
and direct TVOCs CO2 eq.
60 1700 -990
Biofilter
biofilter system
biofilter system and TVOCs
Difference between biofilter and
50 1690 -1000
Adsorption
adsorption system
adsorption system + TVOCs
Difference between adsorption
system and direct TVOCs CO2 eq.
160 1810 -890
It can be seen from Table 8 that the difference in CO2 equivalent emissions from
abatement systems compared with direct release to the atmosphere indicated that all
cleaning systems would have an overall climate change benefit to operate the systems
in order to clean odours and odorous VOC emissions than allowing untreated emission
directly to the atmosphere if we consider environmental aspect and global warming.
3.6 Conclusion, recommendation
Conclusions and recommendation are based on the outcomes of the Odorless casting
pilot tests and the outcomes of the specific offers made for an iron foundry and
cupola furnace melting in Finland. The offers are for 3 different abatement systems.
The systems are biolfiter, regenerative thermal oxidation and adsorption
technologies. In iron foundry Finland, additionally, the ignition system was listed
into the cost comparison (Chapter 3.4 and Table 9.) but it is only for representative
proposal.
Cost efficient abatement technology in whole iron foundry in Finland
The most cost-efficient abatement technology for the waste gas treatment emissions
is biofilter. It is based on the cost comparison results (Appendix 2) and the increase
cost of production due to investment (Table 9). The relatively low odorous VOC
concentration levels fits well for biofiltration. The technical odour cleaning
efficiency can be designed on the level of 80-90 % (VOC 50-70%) and it is low
compared to the RTO of 99 – 99.5 %, which can be achieved in practice with 3-bed
RTO system with concentrator. The oxidation system with two beds achieves the
cleaning efficiency of 97 % and with three beds or continuously changing bed
structure can achieve 99 % in practice. The efficient cleaning system of regenerative

Odorless casting
25
thermal oxidation is tested technology and fits for the purpose but higher investment
costs make the system 20-30 % more expensive with a rotor concentrator system. In
case the source concentration rises over the level of 500 mgHAP/m3
the RTO system
is recommended. Abatement systems cost comparison can be seen from an iron
foundry offer (Appendix 2).
Cost efficient abatement technology in Cupola furnace melting in Finland
The most cost-efficient abatement technology for the waste gas treatment emission is
RTO in case high CO concentration is present. It is based on the cost comparison
results (Appendix 4) and the increase cost of production due to investment (Table 9).
However, CO measured source concentration was 18 000 mg/m3
. The concentration
threshold where CO emission is considered toxic to humans is 35 ppm (43.2 mg/m3
);
therefore it is recommended to treat this high amount of CO. In principle with higher
concentration the more economical the thermal oxidation becomes than catalytic
oxidation system. Abatement systems cost comparison can be seen from the cupola
furnace melting offer (Appendix 4).
The adsorption system seems to be too expensive compared to oxidation and biofilter
because of high deposit costs. The system still needs to be further developed for
foundry odour control purposes.
Table 9 also indicates the cost level increase of the foundry production in case of
odour abatement invest are obligatory for the future operation. The cost increase is
50 – 100 €/casting tons, which corresponds at minimum to 1.5 - 3 % in production
costs. In case of one shift, the operation cost rises to double 3 - 6 % compared to
normal operation time where operation cost rises to 1.5 – 3 %.
In Europe there are more than 4 000 foundries. Most of them locate in city areas or
next to them. It has been estimated that 10 – 20 % of foundries cause severe odour
and HAP emission problems. The claims on foundry odours are often met in the
surrounding. In case of a Finnish iron foundry is regarded as medium size foundry
with odour problems to be abated and they are in Europe 600 foundries. They would
have to invest more than 700 million € which would cause with the running costs an
annually increase of production costs of 120 – 150 million €.
Table 10 reveals the system performance in cleaning efficiency. Oxidation has the
highest efficiency of 99 % (three bed or continuously revolving bed system), biofilter
up to 85 %. Oxidation and biofiltration are the two main systems compared also with
the cost of elimination of emissions. The 75 % of adsorption is still a bit imaginary
goal but technically possible. In the case where high cleaning efficiency i.e. low
emissions are needed RTO is recommended. The pilot foundry example of an
aluminium foundry pointed out that casting production can be operating in densely
populated areas.

Odorless casting
26
Table 9. Annual total cost of biofilter, RTO or adsorption cleaning systems at iron
foundry and cupola furnace melting in Finland
HAPs emission
source and
Abatement system
applied
Annual total cost
of HAPs
abatement system
Increase of the cost
of the casting/melt
due to the use of
HAPs abatement
system
Increased cost
of production
in %
Annual
production
(ton/a)
and
cost of
castings/melt
(€/ton)
Unit €/a €/ton %
Iron foundry
(castings)
3620 ton/a
2900 €/ton
Biofilter 170 000 47 1.6
Regenerative
thermal oxidation
280 000 77 2.7
Adsorption 688 000 190 7
Ignition 69 200 16 0.6*
Cupola furnace
(melt)
7200 ton
2300 €/ton
Biofilter 45 000 6 0.3
Regenerative
thermal oxidation
69 000 10 0.4
Adsorption 105 000 15 0.7
*assumption only

Odorless casting
27
Table 10. The cleaning efficiency and amount HAPs destructed of RTO, biofilter
and adsorption abatement systems at iron foundry and cupola furnace melting in
Finland.
HAPs emission
source and
Abatement system
applied
Cleaning
efficiency of
HAPs abatement
system
HAPs destructed
of abatement
system
Annual cost
per destructed
mass of HAPs
Annual
production
(ton/a)
and
cost
production
(€/ton)
Unit % ton/a €/kg HAPs a
Iron foundry
3620 ton/a
2900 €/ton
RTO 99 44 6.3
Biofilter 85 38 4.5
Adsorption 75 34 20
Ignition ~25 11 6.3*
Cupola furnace
7200 ton
2300 €/ton
RTO 99 1.8** 39
Biofilter 85 1.5** 30
Adsorption 75 1.3** 80
*assumption only **HAPs without CO
***as BAT technology for cupola emission abatement is regarded a system of
CO afterburner + rapid cooling + bag filter

Odorless casting
28
4 Dispersion model of odours in the case study of iron
foundry Finland
Estimation of odour emissions was made in a case study in Finland at an iron foundry.
Calculations were made with SoundPLAN dispersion model with AUSTAL2000
interface. AUSTAL2000 is a three-dimensional Lagrangian particle dispersion model,
which uses actual metrological data and topography of calculation area. AUSTAL2000
is also mesoscale reference model for odour dispersion according to the German
guideline “GIRL”.
Odor assessment is based on the concept of the so called odor hour. An hour is marked
as odor hour if there is a clear odor perception in at least 10% of the time. The
frequency of odor hours is always expressed as percentage of the total number of
hours. The value range is 0 to 100; the unit is ’%’.
Calculations were made in three different situations. Total odour emissions without
abatement systems (APPENDIX 9), odour emissions with abatement system Biofilter
with cleaning efficiency 85 % (APPENDIX 10) and odour emissions with abatement
system RTO with cleaning efficiency 99 % (APPENDIX 11). Calculation area was
limited nearby foundry, approximately 1000 X 1300 meters.
The dispersion model, Appendix 9, illustrates the frequency percentage of odour hours
in the foundry surrounding. The existence of odour hours is below the German limit
value of 10 %, which begins to appear just behind the foundry yard. Two industrial
premises in the direction of north and east stay on the odour area. The nearest
accommodation lay further away from the 5 % frequency limit, which cannot any more
be regarded as odorous area.
The Appendices 10 and 11 are calculated in the emission cases of biofilter in use (App.
10 with the cleaning efficiency of 85 %) and RTO in use (App. 11 with the cleaning
efficiency of 99 %). The biofilter results to the frequency of odour hours less than 5 %
on the foundry yard and the cleaning efficiency of RTO is high enough to avoid all
odour perceptions to the level of less than 1 %.
It can be concluded that with the efficient odour abatement measures in foundries can
avoid odour perceptions to the level of acceptance in the surrounding population.

Cost and energy efficiency assessment of odour abatement systems 7_1_15 Action 15

Cost and energy efficiency assessment of odour abatement systems 7_1_15 Action 15

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