p.1 

OAR Box 1413 

Prepped by Ollie Stewart 

Document Number: 

33) 11-1-33 

Docket Number: 

A-94-52 

Printed 7/9/2008 3:11:21 PM Sheet 33 of 114 
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94-RA111.03 

Demonstration of Capture and Control 

Efficiency for a Styrene Emission Source 

Avinash N. Patkar and Joanne M. Reinhold 

Radian Corporation 

Mason, Ohio 

Gerard Henderson 

IT Corporation 

Cincinnati, Ohio 

^T^^W^WT^^^ ^ 

AIR & WASTE MANAGEMENT 

ASSOCIATIO N 

• 

SINCE 1907 

For Presentation at the 

87th Annual Meeting & Exhibition 

Cincinnati,Ohio 

June 19-24,1994 

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94-RA111.03 

INTRODUCTION 

This paper describes the design and compliance demonstration of a coUection and 

control system for styrene-laden air firom a manufacturing facility. Catalytic oxidation 

was selected to be the control system based on a technical and economic feasibility 

study of several options. Specifications were written for the capture and control 

systems, and the systems were installed. The paper presents the strategy used for 

demonstration of capture and oontroi efficiency values resulting in an overall 

reduction in emissions of 85% as required by the state. 

DESCRIPTION OF OPERATION «-•-...•___ 

The company manufactures side-wall panels used for trailers and recreational 

vehicles. A styrene-based gelcoat is used along with a styrene-based resin in the 

manufacturing process. This paper discusses only the gelcoat operation. 

The gelcoat application process atomizes the resin with a high volume low pressure 

spray system. The gelcoat is applied to a mylar sheet which is unrolled and fed under 

the nozzle and then continuously conveyed down the length of the table by a chain. 

Afler the entire sheet is coated, it is allowed to cure before being transferred to the 

lamination area. 

COLLECTION SYSTEM 

The styrene coUection system for the gelcoat area oonsists of an enclosure around the 

atomization area (AT-1), and diree hoods over the entire lengdi of the table (GC-1, 

GC-2 and GC-3). Figure 1 is a schematic diagram of the gelcoat and atomization 

hoods. The atomizatiot\ enclosure captures the styrene emissions due to the 

atomization and overspray of the gelcoat by the spray nozzle. The three hoods over 

the table capture the styrene emissions ftom the mylar as the curing process takes 

place. 

The atomization hood is a stationaiy enclosure with a door at the operator station. 

The door is raised to set up a new sheet and lowered before starting the spray. The 

gelcoat hoods are lowered in place by a pneumatic system from their inclined resting 

\ 
94-RA1U.03 94-RA111.03 

Election and 

ttalytic oxidation 

nic feasibility 

and control 

-gy used for 

overaU 

national 

resin in the 

oo. 

telow pressure 

led and fed under 

ible by a chain, 

insfetrcd to the 

dosure around the 

the table (GC-l, 

id atomization 

uetothe 

three hoods over 

5 process takes 

perator station, 

g the spray. The 

ar inclined resting 

position. The spray is started and the sheet cures under the hoods for 8-10 minutes. 

The emissions are captured and ducted to the catalytic oxidizer. 

CONTROL SYSTEM 

Thu project initiaUy involved estimating the amount of styrene being emitted from the 

gelcoat operation. The styrene used in the gelcoat actuaUy has a dual purpose. It 

serves as a solvent to keep the gelcoat fluid, but it also serves as a polymerizing agent 

when combined with a catalyst. Therefore, some portion of the styrene in the gelcoat 

is lost to atmosphere due to its solvent role, but a large portion of the styrene reacts 

and polymerizes, causing the gelcoat to cure once it is sprayed onto the mylar. 

Detennining the amount of styrene emitted to the atmosphere, therefore, was not a 

simple material balance calculation. Emission factors were developed and are 

discussed in the next section. 

Once these values were determined, a design baas was established for controlling the 

styrene emissions through add-on control equipment As part of the project, 

alternative coating materials with lower styrene content or other solvents were 

evaluated. These alternative products did not achieve high enough product quality to 

allow the facility to make a product substitution. Several add-on control systems were 

evaluated including adsorption, absorption, condensation and catalytic oxidation. 

Each add-on oontroi system was evaluated based on technical feasibility and economic 

criteria. Catalytic oxidation was selected for several reasons. The facility did not 

want to recover and reuse the styrene because of degraded quality during the recovery 

process with adsorption. Other control systems would be costly and create a 

secondary styrene waste stream requiring further treatment or disposal. 

The catalytic oxidizer is designed to operate at 600-700°F with a recuperative heat 

exchanger to recover heat from the exhaust and use it to preheat the inlet air. This 

heat recovery reduces the amount of fuel (natural gas) required to keep the oxidizer at 

the required temperature for destruction. The oxidizer has a capacity of 

approximately 5000 acfm. 

EMISSION FACTOR DEVELOPMENT 

This section summarizes a gravimetric procedure used to generate the styrene 

emission factors for the gelcoat process. The total emissions from tius process are 

divided into two components, atomization losses and curing losses. Emission factors 

for each of these two components were determined by conducting gravimetric testing. 

The gravimetric testing for the atomization area involved weighing the drum of resin 

before and after spraying and coUecting aU the sprayed resin so that it could be 

wdghed. Losses were determined by calculating the difference between sprayed resin 

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94-RAI 11.03 

and collected resin. Gravimetric testing for the curing losses involved weighing a 

sprayed sheet immediately after being sprayed and weighing it afler curing. The 

difference was determined to be die styrene losses. These emission factors were 

determined to be 0.042 and 0.088 lbs styrene/lb of gelcoat used for the atomization 

and curing losses, respectively. Thus, die total emission factor (Eg) was 0.13 lbs 

styrene/lb of gelcoat used. This factor is for die baseline gelcoat. A "high 

performance" gelcoat material was also used that cures at a faster rate than the 

baseline gelcoat. It was shown to have a total emission factor (Eg) of 0.091 lbs 

styrene/lb of gelcoat used. 

ANALYTICAL AND TEST PROCEDURES 

The overaU control efficiency is the product of die destruction and capture efficiency 

values. The procedures and calculations associated with destruction and capture 

efficiency detennination are described in diis section. Figure 1 shows die sample 

locations at die inlet and outlet of die oxidizer. 

Semi-QiiaatiUtive Capture Efficiency Demoustratioa *"*•--•»_ 

The EPA requires diat die source owner/operator demonstrate adequate capture 

efficiency. In order to demonstrate that the capture efficiency required by the system 

was being achieved, a test protocol using smoke tests, organic vapor analyzer (OVA) 

readings, and velocity measurements near each styrene coUection point was 

developed. Smoke testing was used to visibly demonstrate effective capture of styrene 

emissions from the controlled process area. An aspirator bulb and ventilation smoke 

tubes (Mine Safety Appliances Company, Part No. 458480) were used to generate 

smoke within die zone of influence (approximatdy 1 to 2 inches outside each hood air 

inlet) of each of die styrene collection hoods. Each ventilation smoke tube contains 

two ampules containing ethylenediamine and acetic acid. When the glass ampoules are 

manuaUy crushed, die released vapors react forming a fume composed of aerosol 

particles that is visible as a white vapor. This white smoke has a vapor density that is 

very modi larger tiian that of styrene and hence is a conservative indicator of the 

system capture perfonnance widi respect to styrene. 

An OVA was also used to monitor background concentration of styrene in the area 

around each of the collection hoods. By taking intermittent readings widi die OVA 

during nonnal production operations, it was shown diat diere was no change in the 

background levels of styrene caused by die controlled processes. This provided 

another semi-quantitative demonstration that the capture of styrene by the control 

system is near 95 percent. 

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94-RA1U.03 

I weighing a 

uring. The 

ictors were 

ie atomization 

ras 0.13 lbs 

"high 

: than the 

T 0.091 lbs 

pture efficiency 

id capture 

s the sample 

te capture 

sd by the system 

analyzer (OVA) 

it was 

rapture of styrene 

ntilation smoke 

d to generate 

ide each hood air 

e tube contains 

lass ampoules are 

dof aerosol 

JOT density diat is 

icatorof die 

sie in die area 

with die OVA 

change in the 

• provided 

ir die control 

94-RA111.03 

Velodty measurements were made near each of the openings leading into die control 

hoods. These vdodty measurements were shown to be greater than the minimum 

value recommended by good engineering practice for industrial ventilation. 

Capture Efficiency Demonstration 

In addition to die semi-quantitative capture efficiency demonstration, die state also 

required a quantitative mediod for demonstrating capture efficiency be conducted. 

Capture effidency was determined using EPA Methods 25 and 2SA at die oxidizer 

inlet (Location 1). The gdcoat usage rates and predicted styrene emission rates were 

monitored and calculated during the test program and compared to the Method 25 and 

25A results. 

Mediod 24 analyses was conducted on coating samples from the gelcoat areas. One 

sample was collected at die spray station every 4 hours for a total of 3 samples. 

Analyses by Mediod 24 includes: volatile matter content, water content, density, 

volume solids, and wdght solids. 

Capture effidency was determined using the followingieqtetion: . 

CE « Mi 

EFg 

M, (Location 1) = Styrene measured at incinerator inlet, Ib per period. 

EFg •=• Predicted styrene emitted from gelcoat operation, lb per period. 

Destruction Efficiency DHrrmlnatlon 

Destruction effidency was determined using EPA Mediod 25 at the inlet and oudet of 

the oxidizer. Location 1 and 2 (see Figure 1) represent die inlet and outlet sample 

locations. At die destruction effidency required to demonstrate an overaU control 

efficiency of 85%, die outlet concentration was expected to be close to or less tiian 

50 ppm styrene measured as organic caibon. This would have created uncertainty in 

die outlet mass rate of nonmethane organic carbon calculated by Mediod 25. 

Therefore, a total hydrocarbon analyzer (EPA Mediod 25A) was used in conjunction 

widi die Mediod 25 tests to verify any apparent Mediod 25 outliers and to estabUsh 

die mass flow rate of styrene bang collected from the process areas (see Capture 

Efficiency Detennination). 

Volumetric gas flow rates and composition were determined at cadi site using EPA 

Methods 1-4. One measurement was conducted during each sample run. Moisture 

content was determined at each location using die wet bulb/dry bulb technique. Gas 

molecular weight was determined using Fyrite grab samples. 

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94-RAl 11.03 

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Destruction effidency was determined using the following equation: 

DE « fM, - M,. x 100 

M, 

where: DE = destruction efficiency, % 

M, 

M, 

mass of nonmethane organic carbon at oxidizer inlet, Ib 

per given period (M, is Location 1 on diagram) 

mass of nonmethane organic carbon at oxidizer outlet, Ib 

per given period (M, is Location 2 on diagram) 

Three one hour tests were conducted and the destruction efficiency values wiU be 

calculated. 

OveraU Control Efficiency Determination **•.--___ 

State regulations required die source to have an overall control efficiency of 85 

percent. A control efficiency equal to or greater than the required levd was 

demonstrated during the test program. The overaU control effidency was calculated 

by a combination of the capture and destruction efficiency values, by using die 

foUowing equation: 

OCE - (CD x (DE) x 100 

100 100 

where: OCE = 

CE -

DE -

overaU control efficiency, % 

capture efficiency, % 

destruction effidency, % 

OveraU control efficiency values were calculated for die diree one hour tests. 

RESULTS 

For various test runs, die capture and destruction effidencies were determined. The 

results are summarized in Table 1. Each spray is called an event and die time 

between two sprays is called event time. 

The data showed diat die capture efficiency varied from 90 to 97 percent based on 

event time. The total event time indudes die time required to spray and cure the 

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94-RA111.03 

oxidizer inlet, lb 

diagram) 

oxidizer oudet, Ib 

diagram) 

94-RA111.03 

sheet, lift the hoods up, move die shed to the transfer table, bring the hoods down, 

and set up the new sheet. The capture efficiency can be improved by leaving the 

hood down for a longer period, but diis would lower the production rate. 

The destmction efficiency was very dose to 98% for all the runs. This proves that 

the catalytic oxidizer was not sensitive to die inlet concentration. Aldiough die inlet 

concentration averaged 240 ppm, there were peaks of up to 800 ppm within 2 minutes 

of completing die spray. The destruction efficiency was 98% both at die lowest and 

at die peak concentrations. 

The overaU control effidency varied from 88 to 95%. The system was, dierefore, 

capable of demonstrating compUance with the 85% requirement. 

values win be REFERENCES 

aency of 85 

levd was 

•y was calculated 

iy using the 

1. "Results of Gravimetric Testing for Emissions from Gdcoat Operation Using 

BaseUne and CT-76-HP Resin," Tests conducted by Radian Corp, April 30, 

1993. 

**• -i t 

2. Industrial Ventilation: A Manual of Recommended Practice. Committee on 

Industrial Ventilation, American Conference of Governmental Industrial 

Hygienists. Vol. 17, 1991. 

tour tests. 

determined. The 

id the time 

scent based on 

rand cure die 

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94-RA111.03 

Table 1. Styrene Capture, Control and Overall Efficiencies (a) 

Ron 

No. 

I 

1 

Oeleo-tf 

(lb.) 

46.8 

44.5 

47.2 

49.3 

49.6 

S1.2 

SI.S 

S4.2 

Evert Time 

(minXb) 

IS 

18 

20 

21 

21 

20 

21 

19 

Inl*.<c) 

(Ib/eveot) 

S.6 

J J 

S.S 

6.1 

6.1 

6.2 

6.3 

6.4 

Oml*. (d) 

(Ib/awst) 

0.11 

0.09 

0.10 

0.10 

0.10 

0.11 

O.U 

0.12 

Bfficieaciei <*) 

Capture Do*. 

92.1 98.0 

91.6 98.3 

9 4 J 98.3 

9S.1 98.4 

94.7 98.4 

93.2 98.4 

« • « ^! 4 

90.8 98.2 

Total 

90.3 

90.0 

92.9 

93.6 

93.2 

91.7 

92.S 

88.6 

a: Tests on May 19, 1993. BaseUne gelcoat. EPA Method 2SA modified, 

b: Event time is die duration between two sprays in minutes, 

c: Inld mass is based on 5055 scfm measured. Range of cone. 210-270 ppm. 

d: Outlet mass is based on 5154 scfm measured. Range of cone. 3-5 ppm. 

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94-RAI 11.03 

ure. Control and Overall Effidencies (a) Figure I. Geioool CoUection Hoods and Sampling Locationi 

54 

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Onchi. ( 0 

0.11 

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0.10 

0.10 

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BmOamdm (« ) 

Caf-t-tra DM . 

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Total 

W J 

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«2.t 

WJ» 

WJ 

91.7 

ns 

M.« 

location 2 

OuOat 

18*10 

isetifie gdcooL EPA Method 2SA modified. 

«tween two quays in minutes, 

acfm measured. Range of cone. 210-270 ppm. 

>4 acfm measured. Range of cone. 3-5 ppm. 

1

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/ \MO*ID \»iorio oitrio IMOMD 

Location »V/ *V / " / »V_ 

1 

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AfexiUzaflonHcod 

(900 dm) 

3 Gelcoat 

Collection 

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(000 dm each) 

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