EPA/600/A-96/011
An Assessment of Styrene Emission Control Technologies
for the FRP and Boat Building Industries
Mark Bahner, Emery Kong, and Sonji Turner
Research Triangle Institute
P.O. Box 12194
Research Triangle Park, NC 27709-2194
Norman Kaplan
U.S. Environmental Protection Agency
Air Pollution Prevention and Control Division
Research Triangle Park, NC 27711
ABSTRACT
Styrene emissions from open molding processes in fiber-reinforced plastics (FRP) and boat
building facilities are typically diluted by general ventilation to ensure that worker exposures do not
exceed Occupational Safety and Health Administration (OSHA) standards. This practice tends to
increase the costs of add-on controls, since costs are strongly dependent on air flow rate through the
control system. Also, add-on styrene emission controls are currently not generally mandated by
regulations. Therefore, emission controls are infrequently used in these industries at present. In order to
provide technical and cost information to companies that might choose emission controls to reduce
styrene emissions, Research Triangle Institute (RTI), working with the U.S. Environmental Protection
Agency (EPA), examined several emission control technologies that have been used to treat styrene
emissions in the U.S. and abroad. Control costs for these technologies were developed and compared for
three hypothetical plant sizes. The results of this cost analysis indicate that increasing styrene
concentration in the exhaust streams can significantly reduce cost per ton of styrene removed for all
technologies examined. Therefore, a company should evaluate methods to increase concentrations in the
exhaust stream before considering any add-on control devices This paper also presents air flow
management practices and enclosure concepts that could be used to create a concentrated exhaust stream
while maintaining a safe working environment.
INTRODUCTION
The fiber-reinforced plastics (FRP) and boat building industries have many alternatives for
reducing styrene emissions. Styrene emissions can be reduced by (1) using resin materials and application
equipment that generate less styrene emissions, (2) improving operator techniques to reduce overspray,
(3) changing open-molding processes to closed-molding processes, and (4) using add-on emission control
devices. The amount of reduction achieved by these alternatives, taken separately or in various
combinations, can vary widely For example, the overall efficiency of an add-on emission control system
is a product of the emission capture efficiency and the control system efficiency and thus is less than
either efficiency.
Conventional pollution control technologies are not often used to reduce styrene emissions in the
FRP and boat building industries; low concentrations and high air flow rates have made conventional
emission controls very expensive, and in some cases, less efficient. The FRP and boat building industries
need information regarding the applicabilities and costs of conventional and emerging control
technologies, so they can make informed decisions about the use of controls to reduce their emissions.
To meet this need, Research Triangle Institute (RTI), working with the U.S. Environmental Protection
Agency's (EPA's) Air Pollution Prevention and Control Division, evaluated air flow management
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practices, and the cost and performance of several conventional and emerging pollution control
technologies potentially applicable to these industries.
This paper summarizes the results of literature reviews and control cost analyses. Background
information about the industries and the characteristics of their emissions are provided. The various
pollution control technologies are described, and their costs compared. Air flow management practices
that may reduce control costs are described and evaluated, and conclusions of the evaluation are
presented
This paper provides preliminary technical and cost information to FRP and boat building
companies for their use in selecting emission control technologies Companies should identify those
technologies that suit their production processes, and contact the vendors of those technologies for more
accurate information on equipment costs.
BACKGROUND
The FRP industry (excluding boat building) includes over 680 facilities nationally in as many as 33
different Standard Industrial Classification (SIC) categories ranging from transportation to electronics
and consumer products.1 The FRP industry manufactures products such as bathtubs, shower stalls, spas,
truck caps, vehicle parts, tanks, pipes, appliances, ladders, and railings. The FRP industry employs a
variety of manufacturing processes. As shown in Table 1, the main manufacturing process is open
molding. RTI estimates that open molding (including gel coat and resin spraying) is responsible for
approximately 75 percent of the 15,419 metric tons (17,000 tons) per year of styrene emissions from the
FRP industry. This estimate is based on 1992 Toxic Release Inventory (TR1) reports,2 and RTI's
knowledge of FRP processes and their emission characteristics.
The FRP boat building industry represents a segment of SIC code 3732, Boat Building and
Repairing. A 1990 EPA report3 indicated that 1,822 facilities made up the boat building and repair
industry; however, only 214 of these facilities employed 50 or more people The open molding process is
the most common production method used in FRP boat building. Estimated VOC emissions from the
boat building operations in the U.S. were 19,954 metric tons (22,000 tons) in 1990.3
The open molding process usually consists of applying a liquid gel coat or resin to a mold with a
spray gun in an open environment. Styrene is emitted both during the application stage when gel coat or
resin material is atomized and sprayed onto a mold and during the post-application period when the
material cures. Most FRP production and boat building facilities use high ventilation rates to ensure that
styrene levels are below the 100-ppm worker exposure limit established by OSHA. Dilution increases the
volume of contaminated air and, because the cost of an add-on emission control system is a strong
function of the total air flow, dilute air streams are more costly to control Some facilities designate
certain areas for gel coat or resin spraying to reduce the contamination of plant air. In these cases, a
spray booth equipped with a dry filter medium may be used to reduce particulate emissions, but diluted
styrene emissions are typically vented to the atmosphere directly.
Some FRP processes, such as pultrusion, continuous lamination, sheet molding compound (SMC)
and prepreg production, and resin mixing, have localized and stationary emissions that can be enclosed
and vented to a control device. Emissions from these processes can be captured with lower exhaust flow
rates (i.e., at higher concentrations) than emissions from the open molding process; therefore, they are
more feasible or less costly to treat. Most of the existing emission control devices installed in the FRP
facilities are used to treat emissions from these processes.
POLLUTION CONTROL TECHNOLOGIES AND CONTROL COST ANALYSES
This section describes pollution control technologies that have been used in the U.S. and abroad
to treat styrene emissions and presents cost analyses of these technologies for three hypothetical plant
sizes.
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Pollution Control Technologies
Pollution control technologies include (1) conventional pollution control technologies, such as
thermal and catalytic oxidation and condensation, (2) preconcentration by an adsorption unit, followed by
a recovery or destruction device, and (3) emerging technologies, such as ultraviolet (UV) oxidation, that
are not currently used in the U.S., but have potential to treat styrene emissions.
Conventional Technologies. Four conventional technologies are currently used in U.S.
FRP facilities to treat styrene emissions: thermal oxidation, catalytic oxidation, adsorption, and
condensation. Process descriptions and their applications in the FRP industry are presented.
In thermal oxidation (also called "incineration"), the styrene-containing stream is heated in a
combustion chamber to a predetermined temperature for a sufficient time to convert styrene to carbon
dioxide (C02) and water (H20). Commercial thermal oxidizers operating at 907°C (1,600°F) with a
nominal residence time of 0.75 seconds can achieve 98 percent destruction of non-halogenated organics.4
Auxiliary fuel is used to maintain the high combustion temperature. Thermal recovery, using recuperative
or regenerative heat exchangers, is frequently used to lower the fuel costs of thermal oxidizers. If a shell-
and-tube heat exchanger is used to preheat incoming combustion air, the heat exchanger is called a
"recuperator." Recuperators typically have energy recoveries of 40 to 60 percent, although recoveries of
80 percent or more are possible. Regenerative thermal incinerators cycle thermal energy between an
exhaust and an intake stream using an arrangement of thermal masses. The hot flue gas from the
incinerator heats a storage mass, usually a heat-resistant ceramic material. Once this storage mass
reaches a preset temperature, the flue gas is redirected and the styrene-laden inlet gas flows through the
now heated mass In this manner, up to 98 percent of the thermal energy in the incinerator's exhaust can
be recovered. Due to the higher thermal efficiency, a regenerative thermal oxidizer is typically better
suited for low-concentration streams than a recuperative thermal incinerator. Thermal oxidizers are
currently used in facilities manufacturing sheet- and bulk-molding compounds and prepreg materials, in
facilities using continuous lamination and pultrusion processes, and in some open molding processes.5
Catalytic incinerators modify the thermal incinerator concept by adding a fixed- or fluidized-bed
catalyst to promote the oxidation reaction, allowing faster reaction and/or reduced reaction temperature.
Typical temperatures range from 260 to 650°C (500 to 1,200 °F). A lower reaction temperature
generally reduces auxiliary fuel requirements, thus reducing operating costs. Both recuperative and
regenerative heat exchangers can be applied to catalytic incinerators. Catalytic oxidizers are used in an
FRP facility (Fibercast, Sand Springs, Oklahoma) to treat styrene emissions from bulk-molding-
compound preparation and centrifugal casting and in another facility (CorTec, Washington Court House,
Ohio) to treat emissions from gel coating.5
Adsorption units using activated carbon or polymeric adsorbent have been installed in several
European FRP facilities to preconcentrate styrene emissions for subsequent recovery or destruction
Preconcentration technologies are discussed later At least two FRP facilities in the U.S. (U.S.
Fiberglass, in Middlebranch, Ohio, and Glastic Corporation, in South Euclid, Ohio) use activated carbon
filter panels to treat styrene emissions from their production buildings, which house compression molding
presses, pultrusion lines, and bulk molding compound production. These carbon filter panels are
disposed of after use or sent out for reactivation.5
Condensation is not commonly used to treat styrene emissions. However, an FRP facility
(Premix, Incorporated, Ashtabula, Ohio) recently installed a liquid-nitrogen condenser to recover
styrene.6 The facility originally applied enclosure and nitrogen blanketing on their resin-mixing tank and
sheet-molding-compound manufacturing process to confine styrene emissions. Recently, they decided to
vent the styrene-laden nitrogen to a condenser, which uses liquid nitrogen to remove styrene. This FRP
facility is currently conducting a study to examine the styrene reuse issue. Since the facility already has a
nitrogen source on site, the annual cost for the condenser is less than that for other emission control
systems.
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Preconcentration Technologies. A low-concentration, high-air-flow-rate exhaust stream can be
concentrated into a smaller stream at higher styrene concentration for more economical destruction.
Typically, a preconcentration device can reduce the exhaust flow rate to 10 percent of the original
exhaust flow rate. Consequently, capital and operating costs for a downstream emission control device
can be reduced significantly. A concentrated stream reduces or eliminates the auxiliary fuel required in a
downstream incinerator, resulting in a decrease in operating cost and related emissions of carbon and
nitrogen oxides.
Preconcentration technologies use the adsorption-and-desorption principle to convert a low-
concentration/high-flow-rate exhaust stream into a high-concentration/low-flow-rate stream. Three
preconcentration technologies have been developed by U.S. and European engineering firms The Polyad
system preconcentrates styrene emissions by adsorption on polymer beads, then destroys desorbed
styrene by catalytic oxidation. The Purus PADRE system uses a polymeric adsorbent to preconcentrate
styrene emissions, then recovers styrene after desorption. Alternatively, the desorbed styrene might be
reused if the recovered styrene meets material purity standards. The MIAB concentrators use activated
carbon in fixed- or fluidized-bed designs; both are followed by catalytic oxidation.
Biofiltration. Biofiltration is a relatively recent air pollution control technology in which an
exhaust gas containing biodegradable organics is vented, under controlled temperature and humidity,
through a medium inoculated with cultured microorganisms. The microorganisms contained in the
compost-like medium digest the organic and produce C02 and H20. This technology has been applied in
Germany and the Netherlands in many full-scale applications to control odors, volatile organic
compounds, and air toxic emissions from a wide range of industrial sources. A biofiltration unit has been
installed in an FRP boat building facility in Sweden to treat styrene emissions. The unit was designed for
a 283 m3/minute (10,000 cfin) flow rate and an 85 percent removal efficiency.7 The pH, temperature,
moisture, growth of biomass, and pressure drop of the biofiltration unit need to be monitored carefully to
maintain an optimum condition.8
Ultraviolet Oxidation. Ultraviolet/activated oxygen (UV/AO) oxidation is an emerging
technology that combines UV light oxidation, absorption, and carbon adsorption into a system to treat
volatile organic emissions. The system uses filters to remove particulates from the air stream. The
organic-laden air then enters a photolytic reactor, where it is exposed to UV light and mixed with
activated oxygen/ozone. Partial destruction of the organic vapor takes place in the reactor. The air then
enters a scrubber where organic vapor in the gas phase is transferred to the liquid phase. The water is
heavily oxidized in the scrubber's recycling tank to convert organics into C02 and H20. The air stream
from the scrubber is treated by activated carbon adsorbers to remove any remaining organic vapor that
did not dissolve in water. Activated carbon adsorbers are alternately regenerated on-site using oxidant,
and the adsorbed organic is converted to C02 and H20 This system involves many unit operations that
require careful operation and maintenance A UV/AO system was installed in an FRP job shop in
California to treat styrene emissions from a sprayup operation; however, it is no longer in operation
because the plant was shut down.
Control Cost Analyses
RTI collected capital and operating cost data from several sources in order to calculate annualized
costs for various conventional and emerging control technologies for three hypothetical plant sizes.
Annualized costs were calculated using procedures outlined in the EPA Office of Air Quality Planning
and Standards' OAOPS Control Cost Manual4 Table 2 summarizes the equations for equipment costs
that were used to calculate annual costs. Other cost analysis inputs and major assumptions are presented
in Table 3. All costs were calculated in July 1995 dollars using Chemical Engineering equipment cost
indices.
Based on the quantity of styrene emitted and the control efficiencies of the technologies, the costs
per ton of styrene removed were calculated from annualized costs. Cost curves are presented in Figure 1
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for catalytic oxidation for three hypothetical plants, treating 18, 91, and 363 metric tons (20, 100, and
400 tons) per year of styrene. For each hypothetical plant, a cost curve was developed for different inlet
concentrations (which are inversely related to air flow rates). The cost curves show that cost-per-ton of
styrene removed decreases as the inlet concentration increases (i.e., exhaust air flow rate decreases) For
example, Figure 1 indicates that, for a large plant treating 363 metric tons (400 tons) per year of styrene,
the cost-per-ton of styrene removed decreases from $5,200 to $1,600, if inlet concentration increases
from 50 to 200 ppm. This represents an annual saving of approximately $1.4 million This figure also
shows that costs-per-ton of styrene removed are higher for small plants than for large plants, because of
the economy of scale
Figures 2, 3, and 4 compare cost curves for various control technologies for three hypothetical
plant sizes, under the assumptions presented in Tables 2 and 3 These figures indicate that concentrating
technologies appear to reduce the cost of styrene control, particularly at lower styrene inlet
concentrations. However, this reduction in cost is significantly affected by the equipment cost
assumptions used in this analysis. Therefore, FRP companies should compare costs of different
technologies on a case-by-case basis. These figures also show that, for all control technologies, control
costs can be significantly reduced by increasing styrene inlet concentration (i.e., lowering exhaust flow
rates). Containing or capturing styrene emissions at the source, thus reducing inlet flow rates to control
devices, are good approaches to making any control technology more economically feasible
AIR FLOW MANAGEMENT PRACTICES
Current ventilation systems in FRP and boat building facilities are primarily designed to provide
an environment that is safe for workers and produces good product quality. General ventilation, also
called dilution ventilation, supplies an ample amount of makeup air to dilute the contaminants to an
acceptable air quality level in the workplace. This common practice produces high-volume, low-
concentration exhaust streams. Flow rates of 566 to 2,830 m3/min (20,000 to 100,000 cfm) are common
in FRP and boat building facilities, and styrene concentrations are rarely above 100 ppm. As shown in
the previous cost analysis, these high-volume, low-concentration exhaust streams make emission control
systems more expensive. It is also more expensive to heat or cool large volumes of makeup air.
Proper air flow management would capture emissions at the point of generation and prevent
mixing contaminated air with clean air. Thus, proper air flow management can maintain a safe
environment for the operators, while significantly decreasing exhaust flow rates. These reduced exhaust
flow rates (increased concentrations) can reduce control costs.
The following sections present several air flow management practices and concepts that could be
applied to minimize air flow volumes at FRP and boat building facilities These practices and concepts
are: local air flow management, spray booth modifications, and enclosures. RTI and EPA may
collaborate to test the effects of enclosures and spray booth modifications on styrene emissions, in 1996,
if suitable arrangements can be made.
Local Air Flow Management
Local air flow management involves capturing air pollutants at the emission source directly,
therefore, the amount of air to be ventilated is minimized In an open space, this can be done by blowing
makeup air toward the emission source and capturing the emission with an exhaust hood at the other end
(a push-pull ventilation system). The capture efficiency is generally better for a push-pull system than for
an exhaust hood alone. Figure 5 shows three schematics of local exhaust ventilation that originally
appeared in the UP-Resin Handling Guide .9 These practices are local extraction, in-mold push-pull
ventilation, and out-of-mold push-pull ventilation.
Local extraction is effective when styrene emissions are extracted as close to the mold as possible,
because the effectiveness of the extractor decreases by a factor of four when the distance from the mold
is doubled.9 "In-mold push-pull ventilation" is a technique in which a small amount of air is blown from
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one side of the mold, over the wet mold surface, and immediately captured by an exhaust hood at the
other side of the mold This technique is best-suited for large, female molds (such as boat hulls).
"Vertical push-pull ventilation" directs makeup air from the ceiling toward the mold and pulls emissions
away from the workplace through a down-draft exhaust. When the push-pull ventilation is arranged
horizontally, it is like a spray booth with air pushed at the mold from one direction, and exhaust air pulled
from the other side of the mold. The advantages of these push-pull systems are that less air flow is
required to sweep the high-concentration emissions from the mold surface and that emissions are
captured at the source directly, thus avoiding contamination of the surrounding air.
In-mold push-pull ventilation systems are not common in the U.S., and vertical out-of-mold push-
pull ventilation systems are used only to a limited extent Horizontal push-pull ventilation systems (e.g,
spray booths with forced supply air) are more commonly used in FRP and boat building facilities in
the U.S.
Spray Booth Modifications
Spray booths are commonly used in the FRP and boat building industries, especially for gel coat
and resin sprayup operations, and for parts that can fit into a spray booth. Using a spray booth can
prevent cross-contamination created by general ventilation, because styrene emissions are captured and
exhausted directly. Open-faced spray booths are typically used when molds are manually transferred in
and out of the spray booth on wheels. Spray booths with openings on the side walls are typically used
when molds are transferred mechanically in and out of the spray booth on a conveyor. The latter type of
spray booth is common in high-production facilities
In a typical spray booth, a mold is placed in the center of the booth. Air is drawn into the front
opening of the booth, travels past the mold, and exits through a filter bank at the rear of the booth. Dry
filter media are used to capture overspray, and the media are replaced frequently to protect the duct work
and exhaust system. The captured emissions are vented to the atmosphere or to an emission control
device.
The following sections describe modifications to spray booth design that could increase the
pollutant concentration and decrease the exhaust flow, thus making the downstream emission controls
more cost-effective.
Recirculation. The concept of recirculation had its origin in the spray painting industry, as a
means of lowering the exhaust flow rates (and therefore treatment costs) in paint spray booths.
Recirculation involves redirecting a portion of the spray booth exhaust stream back into the spray booth
This concept is shown in Figure 6. The recirculation stream may be reintroduced at any location in the
spray booth (e.g., near the inlet face, or at the center of the booth) For a spray booth with recirculation
alone, the increase in inlet concentration to a control device is directly related to the amount of
recirculation. The disadvantage of recirculation is the potential for increased worker exposure, unless
fresh makeup air is provided to the operator through a duct, or the operator wears a respirator
Split-Flow. In a typical (horizontal-flow) spray booth, the part being sprayed does not extend to
the full height of the spray booth. Therefore, most of the spraying and post-spraying emissions occur
near the bottom of the booth. A split-flow painting spray booth design that takes advantage of this fact
was developed by EPA and Acurex Environmental, Inc.10 In the EPA/Acurex design, higher-
concentration exhaust air from the bottom of the booth is directed to an emission control device, while
lower-concentration air from the top of the booth is recirculated. This split-flow design is illustrated in
Figure 7. It is possible to have a split-flow spray booth without recirculation, in which case air in the top
portion of the booth is exhausted directly to the atmosphere The main advantage of a split-flow design is
that it produces an increase in VOC concentrations going to a control device, however, the area to be
split must be specific to each spray booth, based on the actual spraying pattern and concentrations at
various locations
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Other Design Modifications. In a typical spray booth in an FRP facility, a mold is placed in the
center of the booth. The arrangement of the mold within the booth is such that higher concentrations are
drawn through the center of the filter bank, rather than through the top or sides of the filter bank. A
spray booth can be modified to take advantage of this spatial difference in concentrations Modification
would involve constructing a smaller, centrally located exhaust device as shown in Figure 8 The higher-
concentration exhaust collected by this device would be directed to an emission control device The
lower-concentration exhaust could be vented to atmosphere or recirculated in the spray booth.
In addition to spatial differences in emissions within spray booths, temporal (time-related)
variations in emissions can be used to increase concentrations to the emission control device. The
centrally located exhaust device could be activated to capture high-concentration exhaust during the
spraying period. The main exhaust of the spray booth will be continuously operating during the
nonspraying or low-concentration period. Periods of high emissions could be determined by
concentration measurements, or high emissions could be assumed to occur during any period of spraying
(i.e., the small exhaust unit is activated by the spray-gun trigger). Fresh makeup air can be supplied to
the locations where the operator is standing.
Enclosures
Enclosures provide a physical barrier between the emissions and the surrounding environment,
and they can reduce or eliminate the dispersion of styrene vapors from a production process. However,
the styrene concentration within the enclosure must be kept below 2,500 ppm (25 percent of the lower
explosive limit) by some ventilation If an enclosure is ventilated, the exhaust concentration is inversely
related to the exhaust flow rate Therefore, an enclosure can be used to confine emissions or to create a
low-flow-rate, high-concentration exhaust stream for destruction
Enclosures are currently being applied to certain emission sources in FRP facilities, such as covers
on resin storage and mixing tanks. The CorTec Company (Washington Court House, Ohio) uses an
enclosed chamber for robotic gel coat spraying; emissions in the enclosure are vented to a catalytic
oxidation unit. The exhaust flow rate is 102 m3/min (3,600 cfm) with an average styrene concentration of
310 ppm.11 Enclosures can also be applied to resin bath or wetout area in continuous lamination,
pultrusion, and SMC production processes. Styrene emissions from these processes are fixed in location
and high in concentration. With proper enclosures, styrene emissions at low flow rates and high
concentrations can be vented to an emission control device and treated economically.
CONCLUSIONS
Exhaust streams from open molding processes in the FRP and boat building facilities are generally
at low styrene concentrations and high air flow rates. General (dilution) ventilation is usually used to
ensure that worker exposure is lower than that allowed by OSHA standards. Treating this low-
concentration, high-air-flow stream is more expensive than treating a low flow rate at higher
concentration. Due to the general practice of dilution ventilation, and the current lack of specific
regulations, add-on control devices are not commonly used in the FRP and boat building industries.
Of the limited number of add-on control devices used in the FRP facilities in the U.S., thermal and
catalytic oxidation are the most common. RTI compared the costs of alternative technologies, including
biofiltration and preconcentration followed by recovery or oxidation, with straight thermal and catalytic
oxidation. Preconcentration technologies appear to reduce the cost of styrene control, particularly at the
lower styrene concentrations (less than 100 ppm) typically found at FRP and boat building facilities.
However, this apparent reduction in cost is significantly affected by the equipment cost assumptions used
in this analysis. Therefore, FRP companies should compare the costs of competing technologies on a
case-by-case basis.
The capital and operating costs of all emission control devices are strongly related to the flow rate
of the incoming stream. Cost analyses indicate, for all control devices examined, that cost per ton of
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styrene removed decreases as styrene inlet concentration increases (i.e., as the air flow rate decreases).
Therefore, it is probably economical to concentrate the exhaust air stream, using proper air flow
management practices or enclosures, before application of add-on emission control devices.
Proper air flow management techniques, which capture emissions at the source, or enclosures,
which prevent styrene emissions from contaminating the plant air, can reduce the exhaust air flow rate
and increase styrene concentration in the exhaust streams from FRP facilities. These approaches can
maintain a safe working environment and produce a high-concentration exhaust stream that makes add-on
emission control devices less expensive.
REFERENCES
1. Pacific Environmental Services; Draft Industry Description Memorandum, Memorandum from Greg
LaFlam and Melanie Proctor, Pacific Environmental Services, Inc., to Madeleine Strum, EPA-
OAQPS, October 17, 1995.
2. 1987-1993 Toxics Release Inventory, EPA-749/C-95-004 (NTIS PB95-503793); U.S.
Environmental Protection Agency, Office of Pollution Prevention and Toxics, Washington, DC;
August 1995.
3. Stockton, MB. and Kuo, I.R.; Assessment of VOC Emissions from Fiberglass Boat Manufacturing,
EPA-600/2-90-019 (NTIS PB90-216532); U.S. Environmental Protection Agency, Research
Triangle Park, NC, May 1990
4. Vatavuk, W.M.; OAQPS Control Cost Manual, 4th Ed EPA-450/3-90-006 (NTIS PB90-169954),
U S Environmental Protection Agency, Office of Air Quality Planning and Standards, Research
Triangle Park, NC, January 1990.
5. G LaFlam, Pacific Environmental Services, Inc., with Emery Kong, Research Triangle Institute,
personal communication, October 3, 1995.
6. D Bonner, Premix Inc., with Emery Kong, Research Triangle Institute, personal communication,
November 7, 1995.
7. Memorandum, from Greg LaFlam, Pacific Environmental Services, Inc., to Plastic Composites
NESHAP Pre-MACT Team and Work Group Members, A summary of vendor teleconference, June
28, 1995.
8 Togna, A.P and Folsom, B.R ; "Removal of Styrene from Air Using Bench-Scale Biofilter and
Biotrickling Filter Reactors," in Proceedings of the Air and Waste Management Association 85th
Annual Meeting & Exhibition, Kansas City, MO, June 21-26, 1992
9. UP-Resin Handling Guide, Jointly published by the European Organization of Reinforced
Plastic/Composite Materials (GPRMC) and the Unsaturated Polyesters Sector Group of European
Chemical Industry Council (CEFIC), 1994, available from the British Plastics Federation, Bath Place
6, Rivington St., GB-London, England, EC2A 3JE.
10. Darvin, C.H and Ayer, J., U.S. Patent 5,221.230, "Paint Spraying Booth with Split Flow
Ventilation," June 22, 1993
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11. Patkar, A.N., Reinhold, J.M., and Henderson G.; "Demonstration of Capture and Control Efficiency
for a Styrene Emission Source," in Proceedings for the Air and Waste Management Association
87th Annual Meeting & Exhibition, Cincinnati, OH, June 19-24, 1994.
12. S Mack, Englehard Corporation, Iselin, NJ, with Mark Bahner, Research Triangle Institute,
personal communication, February 8, 1996
13 T E Josephs, Anguil Environmental, Milwaukee, WI, with Mark Bahner, Research Triangle
Institute, personal communication, January 31, 1996.
14. R Sundberg, Setco, Incorporated (MlAB's representative in the U.S.), Minneapolis, MN, with
Mark Bahner, Research Triangle Institute, personal communication, January 26, 1996.
15. C.L. Irvin, Purus, San Jose, CA, with Emery Kong, Research Triangle Institute, personal
communication, November 8, 1995.
16. Memorandum, from Greg LaFlam, Pacific Environmental Services, Inc., to Plastic Composites
NESHAP Pre-MACT Team and Work Group Members, vendor pre-MACT teleconference, May 16,
1995.
17 Haberlein, R A and Boyd, DP; Maximum Achievable Control Technology for a Hypothetical
Fiberglass Boat Manufacturing Facility, prepared for J. McKnight, National Marine Manufacturers
Association, Washington, DC, August 1, 1995.
18. Vatavuk, W.M.; "A Potpourri of Equipment Prices," Chemical Engineering, August 1995,
pp 68-73.
19. Chemical Engineering Plant Cost Index (Equipment), Chemical Engineering, August 1995; pp 148.
Table 1: Manufacturing processes employed by the FRP industry*
Manufacturing Process Estimated % of Facilities Employing Process3
Open molding (gel coat and resin spraying) 60
Compression molding 17
Filament winding 12
Pultrusion 8
Cultured marble casting 6
Continuous lamination 5
"Column total exceeds 100% because many facilities employ more than one type of manufacturing process Data arc from Reference 1.
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Table 2. Equations for equipment cost (EC).
Item
Condition / Value (July 1995 dollars')
Source
IF Q"<150,000 cfm, $[200,000+15Q]
IF Q> 150,000 cfm, $[450,000+13Q]
Equations in the OAQPS Cost Manual
Catalytic oxidizer
(regenerative,
heat recovery of
95%)
Catalytic oxidizer
(recuperative,
heat recoveries of
70% or less)
Thermal oxidizer Equations in the OAQPS Cost Manual
MIAB $[68,181+16.8Q-2.19E'5Q2]
Purus PADRE
Polyad
Biofiltration
IF Q<3,000 cfin,
IF Q>3,000 cfin,
IF Q<56,000 cfin,
IF Q>56,000 cfm,
$[119,136 + 15.7Q]
$[106,0001^ + 80,000]
$[106,000N + 25Q]
$[214,815 + 16.8148Q
-3.8E~4Q2+ 5.15E"'Q3]
$[284,286+ 10.0316Q
-2.9E"5Q2+ 1.5E"10Q3]
Developed from
quotes from three
vendors.12,13, u
OAQPS Cost Manual
OAQPS Cost Manual
Based on MIAB
equipment cost
quotes.14
Based on Purus
equipment cost sheet,
dated 12/2/94.15
Developed from
Polyad equipment
cost curves, dated
July 1995.16
Developed from Boat
Manufacturing MACT
analysis, dated
8/1/95 17
VOC condenser
Equipment price
escalation (to
Tn1v199M
Single-stage >10 tons, $[0.95exp(9.26-0.007Tconc
+ 0.6271nRd)]
Multistage, $[0.95exp(9.73-
0.012Tcon + 0.5841nR)]
As appropriate
Chemical
Engineering, August
1995.18
Chemical
Engineering
F.nninment Cost Index
"Q= Air flow rate, in scfm (1 scfm = 0.0283 mVminute). trN=Number of adsorption/desorption units (1 unit for every 12.S kg/hr [27.5 Ib/hr]
of styrene) cTcon-Condenser operating temperature (-23"C [-10°F] for single-stage, -40°C [-40"F] for multistage). dR-Refrigeration
capacity, tons.
10
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ES96-S6
Table 3. Other cost analysis inputs and significant assumptions.
Item Value (July 1995 dollars) Source
Purchased equipment
cost (PEC)
1 2 X EC (Includes instrumentation, sales tax,
freight.)
OAQPS Cost Manual
(except sales tax = 5%,
not 3%.)
Direct installation costs
0.30 X PEC (Includes foundations and supports,
handling and erection, electrical, piping, insulation
for ductwork, painting )
OAQPS Cost Manual
Site preparation
(SP)
$[5,000 + 2.3Q']
RTI assumption
Buildings (Bldg)
Not required.
RTI assumption
Indirect costs for
installation
0.31 X PEC (Includes engineering, construction
and field expenses, contractor fees, start-up,
performance test, and contingencies.)
OAQPS Cost Manual
Total Capital
Investment (TCI)
(1.61 X PEC) + SP + Bldg.
OAQPS Cost Manual
Direct operating costs,
minus utilities
(DOCMU)
S0.598Q + 4,840 + Miscellaneous costs
(Includes operating, maintenance, and supervision
labor; annual maintenance contract, miscellaneous
costs)
RTI assumption
Miscellaneous costs
As appropriate. (Includes catalyst and/or
adsorbent replacement costs, start-up fuel cost,
etc.)
Based on vendor
information.
Overhead,
administration, property
taxes, insurance
0,6(DOCMU) + 0.04(TCI)
OAQPS Cost Manual
Plant operating
schedule
4,000 hours per year
RTI assumption
Electrical cost
$0 06/kWh
RTI assumption
Fuel cost
$4 27/billion joule ($4.50/million Btu)
RTI assumption
Capital Recovery
Factor
0,14569
7 5% interest,
10-vear denreciation
¦Q= Air flow rate, in scfm (1 scfm - 0,0283 m'/minute).
11
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ES96-56
10000
c 9000
o
"O
9
8000
6000
5000
4000
o. 2000
"5>
8 1000
| r\
j . 1 !
,n! i %
i i
: . 1 , |
- - - 20 tons per year at inlet, 4000 hours per year operation 1 i
100 tons per year at iniet, 4000 hours per year operation
— —400 tons per year at inlet, 4000 hours per year operation —
I ¦ 1
! % i
* :
% :
; i : i
! ; ; i •
\ \ x *
¦ : ' !
;\ \ V
; ; ?
w
*
j \
1 \ V
% j
I ; • ' ; 1
i \ ^ i
i ¦
! 1 V X. ' ~ "
p— 3*
m m m ^
I
\ ;
100 200 300 400
Concentration (ppm)
500
600
700
Figure 1. Cost curves for a catalytic oxidizer with 70% heat recovery (H.R.).
12,400
10000
6.200
3,100
Flow rate (cfm)
2,066 1,550
MlAB
Polyad (w/oxidation)
Catalytic oxidizer (95% H.R. below 100 ppm)
Thermal oxidizer (95% H.R, below 100 ppm)
Biofiltration
Purus PADRE
886
J
£5 8000
> 7000
•VOC Condenser
§3000
"2000
8 !
°1000 -
0
0
100
200
500
300 400
Concentration (ppm)
Figure 2. Cost curves for a small plant (20 tons per year inlet).
600
700
Id.
-------
ES96-56
62,000
I 31,000
15,500
Flow rate (cfm)
10,333 7,750
6,200
5,166
4,410
"MIAB
Polyad (w/oxidation)
•Catalytic oxidizer (95% H.R. below 200 ppm)
Thermal oxidizer (95% H.R. below 300 ppm)
Biofiltration
Purus PADRE
- VOC Condenser
L_
! : yv 1 ¦ !
V N4 1 "* »
¦ ; !
o
100
200
500
600
300 400
Concentration (ppm)
Figure 3. Cost curves for a medium-size plant (100 tons per year inlet).
700
10000
c
2
w
"O
01
>
o
E
V
-------
(Reproduced with permission from "IJP-Resin
Handling Guide.")
ES96-56
I I 1 I I i i
A
|
Local extraction In-mold push-pull ventilation Out-of-mold push-pull ventilation
Figure 5. Three methods of local extraction ventilation.
Fresh makeup
air intra
Booth intake
Recreutatwn
To treatment
Fresh makeup
air irtake
Boo Eh intake
duct
\
Figure 6. A spray booth with recirculation.
Reoicuiaiiofl
dud
z
Split-flow
duct
To treatment
Figure 7. A spray booth with split-flow
and recirculation.
Mam exhaust to atmosphere
(high volume, low oooceniraton)
Fresh arr
supply
Mam
Local captuie
exhaust to an
emtssion control
device
{low volume.
high concentration)
Small, centrally located
capture device
Figure 8. A spray booth with a centrally located exhaust device.
14
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hd»iidt T>rr-n t-j non TECHNICAL REPORT DATA
NKMRL-RTP- P~0o9 {Please read Iiutrucliom oa the reverts be/one complete
—
1. REPORT NO, 2.
EPA/600/A-96/011
3. «
4. TITLE ANO SUBTITLE
An Assessment of Styrene Emission Control Technol-
ogies for the FRP and Boat Building Industries
S. REPORT DATE
6. PERFORMING ORGANIZATION CODE
7. AUTHOR
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