United States
Environmental Protection
sncy
Industrial Environmental Research
Laboratory
Research Triangle Park NC 27711
Research and Development
EPA-600/S2-83-041 Aug. 1983
<&ER& Project Summary
Control of Hydrocarbon
Emissions from Cotton and
Synthetic Textile Finishing Plants
R. Chandrasekhar and E. Poulin
This report describes the approach
to, and conclusions resulting from, an
evaluation of the applicability and eco-
nomics of emissions control technolo-
gies for the abatement of volatile or-
ganic compounds emanating from cot-
ton and synthetic textile finishing
plants. A survey of the state-of-the-art
and control technologies design and
costing preceded the evaluation. The
economic feasibility was determined
in two steps: preliminary design, cost-
ing, and relative ranking of all identi-
fied applicable technologies; followed
by more detailed design, costing, and
evaluation of the most economically
feasible technologies.
A simple payback period approach
was taken in the preliminary ecomonic
evaluation. Rates of return on capital
investment were determined for the
final detailed evaluation. Capital and
operating costs are provided to allow
interested parties to conduct in-house
evaluations.
Carbon bed adsorption with solvent
recovery has been identified as the
most viable of all technologies, and
fluidized-bed carbon adsorption has
the best potential to suit the variable
operating conditions encountered in
textile manufacturing.
The potential cost benefits, even
under far more stringent control re-
quirements than existing regulations
for the industry, appear attractive.
This Project Summary was developed
by EPA's Industrie/ Environmental Re-
search Laboratory, Research Triangle
Park NC, to announce key findings of
the research project that is fully docu-
mented in a separate report of the
same title (see Project Report ordering
information at back).
Introduction
The U.S. EPA has been studying tech-
nical feasibility and socioeconomic effects
of air pollution control prior to providing
state, local, and other regulatory agencies
with guidelines and technical assistance.
Currently available information for hydro-
carbon control is very general and difficult
to apply to any particular industry. EPA,
through previous studies, established that
textile processing contributed significantly
to the hydrocarbon concentration in the
atmosphere and needed a control method.
The EPA contracted with Foster-Miller,
Inc. to conduct a state-of-the-art study and
acquire technical and economic informa-
tion to enable the design, construction,
and demonstration of a fulkscale hydro-
carbon emissions control unit capable of
95 percent hydrocarbon removal on a
textile fabric processing plant for EPA's
use in its regulatory guidelines and tech-
nical assistance program.
A systematic stepwise approach for the
successful completion of the program was
undertaken to:
• Survey the textile processing indus-
try and published information to de-
termine emissions sources, nature of
pollutants, and range of emissions.
• Investigate the types and effective-
ness of control devices now in place
in the textile industry.
• Investigate hydrocarbon emission
control technologies used in other
industries which may be applicable
to hydrocarbon control in the textile
industry.
• Conduct preliminary design and eval-
uation of applicable control technol-
ogies capable of reducing hydrocar-
bon emissions by 95 percent for a
given stack gas temperature, flow
rate, and a range of concentrations.
-------
• Provide more detailed designs and
cost estimates for the most appro-
priate technologies for varying emis-
sions concentrations and flow rates.
State-of-the-Art Survey
The state-of-the-art survey led to the
following conclusions:
• Textile fabric production is geared to
the marketplace. The volumes of
products, types of fabrics, types of
operations (dyeing, printing, final
finishing), volumes and types of sol-
vent used, and the natures and ranges
of emissions are highly variable.
• Fabric printing has the most poten-
tial for high hydrocarbon emissions;
control technologies should address
this operation.
• Current emissions regulations are
qualitative and address only opacity
or odor threshold. Regulations vary
between states.
• Opacity is controlled by limiting
aerosol emissions, the cause of opac-
ity. Control devices include coalesc-
ing filters, electrostatic precipitators
(ESPs), direct contact condensers,
and demisters.
• Odor is controlled by dilution or
incineration.
• No quantitative data are available on
any control device now in use in the
textile industry.
Applicable Control Technologies
The following control technologies were
determined to be applicable for hydro-
carbon emissions control in general:
• Aerosol formation and paniculate
capture; conventional particu late con-
trol devices include demisters/cy-
clones, scrubbers, filters, and ESPs.
• Incineration, including fixed- and
fluidized-bed catalytic.
• Adsorption, including fixed- and
fluidized-bed.
• Absorption.
A further analysis of the above tech-
nologies in the textile plant exhaust envi-
rons for 95 percent control narrowed the
choices to:
• Refrigeration/condensation + aero-
sol removal.
• Thermal incineration.
• Fixed-bed catalytic incineration.
• Fluidized-bed catalytic incineration.
• Fixed-bed adsorption.
• Fluidized-bed adsorption.
Preliminary Design and
Evaluation of Applicable
Control Technologies
Having identified the emission control
technologies particularly suited to textile
printing plant stack gases, preliminary
design and assessment of these tech-
nologies were made using design rules
given in engineering manuals. Most of
these are based on equipment industry
practices and field experience in operating
these control devices for volatile organic
compound (VOC) pollution abatement
both in and outside the textile industry.
Capital and operating costs were devel-
oped to include optional heat recovery in
incineration systems and the possibilities
of using any solvent recovered in refrigera-
tion or adsorption systems back in the
process or as supplementary fuel.
Costs for systems designed for opera-
tion at 200, 3000, and 8000 ppm stack
gas are given in Table 1 under Cases 1, 2,
and 3, respectively.
Since textile mill operating practices
necessitate varying the print paste solvent
content frequently, causing variations in
the VOC emissions, several combinations
of operations at 200, 3000, and 8000
ppm emissions during different periods of
a year, have also been considered The 10
combinations chosen, where operations at
any one concentration occur for less than a
whole year, are shown in Table 2 as Cases
4 through 13. Thus, Case 6 conditions
refer to an operation where the emissions
are 3000 ppm for 80 percent and 8000
ppm for 20 percent of the year. The costs
and economic impact as represented by
payback periods of varying concentration
levels during operation, are listed in Table
1. Systems that did not result in paybacks
were excluded from further consideration.
The above analyses lead to the following
preliminary conclusions:
• The only control technology with
projected paybacks for all concentra-
tion conditions considered is fluidized-
bed adsorption with recovered sol-
vent reused. No other technology
projects a payback for 100 percent
operation at the low concentration
level (200 ppm).
• As long as operations at low level
exhaust concentration is not more
than 80 percent, fixed-bed adsorp-
tion and refrigeration/condensation
(both with reuse of recovered sol-
vent) also project reasonable pay-
backs for all other concentration
combinations.
• Considering the top three technol-
ogies ranked by average payback,
the payback for fixed-bed adsorption
and refrigeration/condensation is ap-
proximately 200 and 350 percent,
respectively, more than that of fluid-
ized-bed adsorption (all with recov-
ered solvent reuse).
• The fourth ranked technology is
fluidized-bed adsorption with recov-
ered solvent used as fuel. This tech-
nology actually projects shorter pay-
backs than refrigeration/condensa-
tion with solvent reuse if operation
never occurs at high exhaust con-
centration (8000 ppm).
• Fluidized-bed catalytic incineration
and thermal incineration (both with
heat recovery) are closely ranked
technologies. Overall, the former has
the fifth best average payback, al-
though the latter projects better pay-
backs when high concentrations
never occur during operation.
• The final three technologies consid-
ered, in order of average payback, are
fixed-bed catalytic incineration with
heat recovery, fixed-bed adsorption
with recovered solvent used as fuel,
and refrigeration/condensation with
recovered solvent used as fuel. In
order for these techniques to realize
a reasonable payback, concentra-
tions must be in the medium (3000
ppm) to high (8000 ppm) range
more than 50 percent of the time. In
order for refrigeration/ condensation
with solvent as fuel to project a
payback of less than 10 years, more
than 20 percent operation in the
high range is required if the remain-
ing operation is at medium concen-
tration (more than 50 percent is
required in the high range if the
remainder is at low concentration).
• Because the value of recovered sol-
vent is three times greater with reuse
than as fuel, systems with solvent
recovery have better paybacks with
reuse.
• Fluidized-bed adsorption has a short-
er payback than fixed-bed adsorp-
tion despite nearly equal capital
costs, due to the lower utility and
maintenance costs of the former.
Detailed Design and Costing of
Selected Control Technologies
The design and costs for the adsorber
and catalytic incineration systems were
developed in sufficient detail in the pre-
liminary analyses to allow a reasonable
cost-benefit evaluation of these technolo-
gies. The refrigeration/condensation
aerosol removal system and the thermal
incineration system designs were con-
sidered in more detail in order to provide a
more comprehensive basis for final ranking
of applicable emission control technologies
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Table
Case
No.c
1
2
3
4
5
6
7
8
9
10
11
12
13
1. Effect of Changes in Duration of Emissions at Different Concentrations on the Economics of Selected Control Technologies
Identification No.*b
Cost
Hem 1 II IV VI VII VIII IX X XI Comments
Capital
Annual
direct?1
Payback
Capital
Annual
direct
Payback
Capital
Annual
direct
Payback
Capital
Annual
direct
Payback
Capital
Annual
direct
Payback
Capital
Annual
direct
Payback
Capital
Annual
direct
Payback
Capital
Annual
direct
Payback
Capital
Annual
direct
Payback
Capital
Annual
direct
Payback
Capital
Annual
direct
Payback
Capital
Annual
direct
Payback
Capital
Annual
direct
Payback
505. WO
-75.200
-
505. 100
+250.800
2.0
505.100
+820.800
0.6
505. 100
-10.000
-
505,100
185.600
2.7
505. 100
+364.800
1.4
505.100
+706.800
0.7
505.100
+55.200
9.2
505.100
+283,200
1.8
505, 100
+462,400
1.1
505, 100
+478,800
1.1
505,100
+59Z800
0.9
505, 100
+331.300
1.5
505,100
-91,500
-
505, 100
+10,800
47
505,100
+195,800
2.6
505, 100
-71,000
-
505, 100
-9,700
-
505. 100
+47.800
10.6
505, 100
+ 158.800
3.2
505, 100
-50.600
-
505, 100
+23,400
22
505, 100
+80,900
6.2
505, 100
+84.800
6.0
505, 100
+121,800
4.1
505,100
+38, 100
13
165,600
-21,100
-
174,800
+80,600
2.2
324, 100
+249, 100
1.3
174,800
-800
-
174,800
+60,300
2.9
324, 100
+114.300
2.8 •
324. 100
+215,400
1.5
174.800
+19.600
8.9
324, 100
+87,000
3.7
324. 100
+141,000
2.3
324, 100
+148,000
2.2
324. 100
+181,700
1.8
324. 100
+102.600
3.2
185,700
-34,300
-
240,400
+60,200
4.0
469,300
+211.500
2.2
240.400
-15,400
-
240,400
+41,300
5.8
469,300
+90,500
5.2
469.300
+ 181.200
2.6
240,400
+3,500
69
469,300
+64,000
7.3
469,300
+113,200
4.1
469,300
+120,700
3.9
469.300
+151,000
3.1
469.300
+78,900
5.9
214,300
-37,800
-
224,800
+63,300
3.6
256.500
+242,500
1.1
224,800
-17,600
-
224.800
+43,100
5.2
256,500
+99, 100
2.6
256,500
+206,700
1.2
224,800
+2,600
86
256,500
+74,300
3.5
256,500
+ 130,400
2.0
256,500
+135,000
1.9
256.500
+170,800
1.5
256,500
+89, 100
2.9
140,000
-7,200
-
140,000
+262.500
0.5
259,600
+734.300
0.4
140,000
+46,700
3.0
140.000
+208.600
0.7
259,600
+356,900
0.7
259,600
+639.900
0.4
140,000
+100,700
1.4
259.600
+289,400
0.9
259.600
+437,700
0.6
259.600
+451,200
0.6
259.600
+545,600
0.5
259,600
+329,200
0.8
140,000
-23,900
-
140.000
+32,700
4.3
259.600
+121,000
2.1
140,000
-12,000
-
140,000
+21,400
6.5 .
259,600
+50,400
5.2
259.600
+103,300
2.5
140,000
-1,300
-
259,600
+34/00
7.6
259,600
+63,000
4.1
259,600
+68,000
3.8
259,600
+85,700
3.0
259,600
+43,200
6.0
84,800
+13.000
6.5
122,500
+314,800
0.4
177,200
+857,900
0.2
722500
+73,400
1.7
722500
+254,400
0.5
177,200
+423,400
0.4
177,200
+749,300
0.2
122,500
+ 126,700
1.0
177.200
+351,000
0.5
177,200
+519,900
0.3
177,200
+532,000
0.3
177.200
+640.700
0.3
177.200
+394,400
0.4
84,800
-3,700
-
12Z500
+85,000
1.4
177,200
+244,600
0.7
122,500
+ 14.000
8.8
12Z500
+67,300
1.8
177,200
+ 116,900
1.5
177,200
212,700
0.8
722500
+37,800
3.9
177.200
+95,600
1.9
177,200
+145,300
1.2
177,200
+ 148,800
1.2
177,200
+180,800
1.0
177,200
+108,400
1.6
100% low concentration
100% medium concentration
100% high concentration
Predominantly low some medium
concentrations
Predominantly medium some low
concentrations
Predominantly medium some high
concentrations
Predominantly high some medium
concentrations
All operations at low and medium
concentrations
All operations at low and high
concentrations
All operations at low and high
concentrations
All operations at medium and high
concentrations
All operations at medium and high
concentrations
Operations at low, medium and high
concentrations
aSee Table 3 for identification numbers.
'Systems ill and V excluded because they did not result in paybacks.
cSee Table 2 for case numbers.
dPositive annual direct costs indicate revenue; negative annual direct costs indicate expenditures.
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Table 2. Changes In Duration Of Emissions at Different Concentrations
Emissions concentration for percent of year
R= C
Description
Operation at single
concentration level
Predominant concen-
tration level with
overlap into one
other level
Operation at two
concentration levels.
one slightly dominant
Case
No.
1
2
3
4
5
6
7
8
9
10
11
12
200 ppm
100
0
0
80
20
0
0
60
60
40
0
0
3000 ppm
0
100
0
20
80
80
20
40
0
0
60
40
8000 ppm
0
0
100
0
0
20
80
0
40
60
40
60
where:
R =
C =
Operation at all levels
equally
13
33
34
33
Analyses at 200 ppm were presented
since the overall economic viability of a
system is greatly influenced by system
performance at low emission concentra-
tions.
Table 3 summarizes the capital cost and
annual direct costs of emissions control
technologies determined from the detailed
system designs and economics. The sys-
tems listed generate revenue at stack gas
concentrations of 8000 ppm or less for
the given stack gas temperature, flow rate,
and relative humidity. Each system has
been designed for the specified emissions
concentration, and a 10 percent thermal
loss has been assumed for each heat
exchanger employed. Also the solvent
recovery efficiency is assumed to be 90
percent to account for solvent replacement
and recovery inefficiencies. If a heat
recovery exchanger is used to warm dryer
air, the mass flow rates on each side of the
exchanger have been assumed equal. If
the recovered waste heat is transferred to
boiler feedwater, a flow rate of 100 gpm
has been assumed. As was the case for all
previous cost reports, annual direct cost is
equal to annual operating savings minus
annual operating costs. Therefore, a posi-
tive direct cost indicates earned revenue,
and a negative direct cost indicates a net
annual expenditure.
In order to determine the systems with
the greatest potential for application, an
annual return rate for each system and
stack gas concentration has been deter-
mined using the following model of capital
recovery in a uniform series:
annual return required on capital
investment $/year
capital cost of system, $
i = annual rate of return, fraction
n = system life, years
Thus, the rate of return values, i, asso-
ciated with the revenue generated, R
(positive direct cost), and money invested,
C (capital cost), for each system reported
in Table 3 have been determined
The estimates of rate of return on invest-
ment (ROI) show that:
• Fluidized-bed carbon adsorption with
solvent reused projects the best ROI
at every stack gas concentration level
by a wide margin. It is also the only
system which generates revenue at
200 ppm. Fluidized-bed carbon ad-
sorption is still the best technology
overall if recovered solvent can only
be used as fuel.
• Fixed-bed carbon adsorption with
solvent reused projects excellent ROI
values for 3000 and 8000 ppm. If
recovered solvent can only be used
as fuel, however, the rate of return is
seriously reduced: other technologies
are preferable.
• The refrigeratiorv'condensation aerosol
removal system is competitive only
at 8000 ppm stack gas concentration
and only if the recovered solvent can
be reused.
• Thermal incineration provides reason-
able ROI at 3000 and 8000 ppm.
Table 3. Summary of Costs for Selected Emissions Control Technologies Including Detailed Designs
I II IV VI VII VIII
IX
XI
Thermal incinera-
Refrigeration/ tion (stack gas
condensation, diluted to 3500
aerosol removal ppm, if higher!
Stack gas emissions Recovered
concentration so/vent
(ppm, volume) Cost item reused
200 Total capital 691,600
cost ($1
Annualdirect -147,600
cost (f/year)
3000 Total capital 706,300
cost ($)
Annualdirect +175,800
cost /t/yearj
8000 Total capital 613,500
cost ($)
Annualdirect +687,200
cost ($/year)
Recovered
solvent
used as
fuel
691,600
-161,900
706.300
-35,200
685,700
+160.000
Heat
recovery
169.600
-40,000
174,800
+69,600
324,100
+219,900
Fixed-bed catalytic Fluid/zed- Fixed-bed carbon
incineration (stack bed cats- adsorption (stack gas
gas diluted to lytic in- diluted to 3500 ppm, Fluidized-bed
1580 ppm, if higher) cineration if higher/ carbon adsorption
Heat
recovery
185,700
-40,000
240.400
+49.200
469.300
+182300
Recovered
Heat solvent
recovery reused
214.300 140,000
-43,700 -9.700
224,800 140,000
+47,100 +228,600
256,500 259,600
+207,900 +643,800
Recovered Recovered
solvent Recovered solvent
used as solvent used as
fuel reused fuel
140,000 84.800 84.800
-24,700 +10,500 -4.500
140,000 122500 122,500
+21,800 +280,900 +74,100
259,600 177,200 177,200
+91,800 +767,400 +215,400
Notes: Negative annual direct cost indicates expenditure; positive annual direct cost indicates earned revenue.
-------
• Fixed- and fluidized-bed catalytic in-
cineration generate competitive re-
turns only at 8000 ppm.
• At 8000 ppm fluidized-bed catalytic
incineration is preferable to either
thermal incineration or fixed-bed
catalytic incineration.
Effect of Stack Gas Flow Rate
on the Economics of Selected
Control Technologies
Figure 1 shows the ROI factors for the
best six technologies versus stack gas
flow rate. Hence, if the ROI for one
selected emissions control system operat-
ing at 3000 ppm is known for a particular
flow rate, the ROI for smaller or bigger
units can be ascertained from Figure 1.
For the selected systems operating with
8000 ppm stack gas, the ROI factors for
gas flows higher than 5000 scfm are the
same as those shown in Figure 1, except
for fluidized-bed catalytic incineration and
2.0 r-
refrigeration/condensation. The ROI fac-
tors for these two systems are about 80
percent of those shown. For 8000 ppm
stack gas and a flow rate of 1000 scfm,
the ROI factors forf luidized- and fixed-bed
adsorption are the same as those illustrated.
The ROl factor for all other systems at
8000 ppm and 1000 scfm is approximately
0.49 (±0.05).
With 200 ppm stack gas only fluidized-
bed carbon adsorption with solvent re-
used projects a return, and only for flow
rates greater than 5000 scfm.
The ranking of the top three technologies
does not vary with stack gas flow rate.
Conclusions
The technological and economic evalua-
tions presented resulted in the following
conclusions:
• Activated carbon adsorption and in-
cineration are the only technologies
capable of achieving over 9 5 percent
emissions control.
7.5
o
ec
§
u
•s
6
ct
1.0
0.5
0.0
I
I
Fluidized-Bed Absorption
with Reuse
— •— — • Fixed-Bed Absorption
with Reuse
•———• Fluidized-Bed Adsorption
with Fuel
•"• * ~~ •• Thermal Incineration
with Heat Recovery
~" •• •"• ** Fluidized-Bed Incineration
with Heat Recovery
—" Refrigeration/Condensation
with Reuse
I
1000 5000
Q. Stack Gas Flow Rate (scfm)
10.000
Figure 1. Economics of size for selected emissions control systems. (3000 ppm stack gas
concentration)
• Direct or indirect condensation using
refrigeration can approach 95 per-
cent control.
• Cyclones, scrubbers, fabric filters,
demisters, electrically augmented
precipitators, and other paniculate
(aerosol) collection devices are not
suitable for 95 percent control with-
out refrigeration.
• For the best six control technologies
and a stack gas concentration of
8000 ppm, the ROIs for 1000 and
10,000 scfm gas flow rates are,
respectively, about 0.52 and 1.29
times that for a 5000 scfm system.
The changes in ROI with flow rates
vary widely when stack gas concen-
tration is 3000 ppm. At 200 ppm
only fluidized-bed carbon adsorption
projects a return, and only at greater
than 5000 scfm.
• Applicable technologies for 95 per-
cent hydrocarbon removal rank in
the following general order of eco-
nomic viability on the basis of ROI:
- Fluidized-bed activated carbon ad-
sorption with recovered solvent
reused.
- Fixed-bed activated carbon adsorp-
tion with recovered solvent reused
- Fluidized-bed activated carbon ad-
sorption with recovered solvent
used as fuel.
- Thermal incineration with heat re-
covery.
- Refrigeration condensation/aerosol
capture with recovered solvent re-
used.
- Fluidized-bed catalytic incineration
with heat recovery.
- Fixed-bed catalytic incineration with
heat recovery.
- Fixed-bed activated carbon adsorp-
tion with recovered solvent used as
fuel.
- Refrigeration condensation/aerosol
capture with recovered solvent used
as fuel.
Recommendations
Based on the results of this study,
Foster-Miller suggests several areas where
further study could advance the state-of-
the-art:
• Solicit the cooperation of a textile
fabric finishing plant which has an-
nual solvent used in its printing op-
erations representative of the industry
average; select the most appropriate
stack for control.
• Determine stack gas conditions:
species emitted, concentration and
its variability, flow rate, temperature,
moisture content etc.
-------
Conduct detailed design and cost
evaluation of two best available con-
trol technologies, specifically for the
stack selected.
Fabricate, install, and demonstrate
the more economically viable control
technology.
R. ChandrasekharandE. Poulinare with Foster-Miller, Inc.. Waltham, MA 02154.
Bruce A. Tichenor is the EPA Project Officer (see below).
The complete report, entitled "Control of Hydrocarbon Emissions from Cotton and
Synthetic Textile Finishing Plants," (Order No. PB 83-209 676; Cost: $16.00.
subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Industrial Environmental Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
•&U. S. GOVERNMENT PRINTING OFFICE: 1983/659-095/0725
-------
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