United States
               Environmental Protection
               Agency
Air and Energy Engineering
Research  Laboratory
Research Triangle Park, NC 27711
               Research and Development
EPA/600/SR-94/211  January 1995
EPA      Project Summary
               Evaluation  of a Liquid  Scrubber
               System  for  Styrene  Removal
               Larry Felix, Randy Merritt, and Ashley Williamson
                 Manufacturing processes that involve
               the  spraying of styrene-based  resins
               have been identified as a possible sig-
               nificant source of volatile organic com-
               pound emissions  that may affect hu-
               man health and contribute to the ozone
               non-attainment problem.Until  recently,
               no known cost-effective technology has
               been demonstrated toontrol such emis-
               sions of styrene. Now,  several pro-
               cesses have been developed to control
               styrene emissions,  and  a short-term
               field evaluation was planned to charac-
               terize the styrene removal efficeincy of
               a pilot-scale version of a liquid chemi-
               cal  scrubbing process. This test was
               carried out at a  facility  (Eljer Plumb-
               ingware in  Wilson, NC) that manufac-
               tures polyester bathtubs and shower
               stalls by spraying styrene-based res-
               ins  onto molds in vented, open spray
               booths. A side stream of  air exhausted
               from one of the spray booths in the gel
               coating part of the process was used
               for the test.
                 In this study the syrene removal effi-
               ciency of a pi lot-scale version  of the
               QUAD Chemtact™ scrubber was quan-
               tified by continuously measuring the
               toatl hydrocarbon (TCH) content of
               spray booth exhaust air  entering and
               exiting the device with THC analyzers
               and, for some tests, by collecting EPA
               Method 18 samples (adsorption tube
               procedure) at the  inlet and exit of the
               device. Average styren removal efficien-
               cies approached but were never >55%.
                 This Project Summary was developed
               by EPA's Air and Energy Engineering
               Research Laboratory, Research Tri-
               angle Park, NC, to announce key find-
ings of the research project that is fully
documented in a separate report of the
same title (see Project Report ordering
information at back).

Introduction
  The report describes an evaluation  of
the QUAD Chemtact™ chemical scrubber
for controlling styrene  emissions at Eljer
Manufacturing  in  Wilson,  NC. The Eljer
facility manufactures shower stalls and
bathtubs  by spraying styrene-based res-
ins  onto molds in  vented,  open spray
booths. Approximately 200 of these types
of facilities  operate  presently in the U.S.
The manufacturing process consists mainly
of four stages. Stage  1  is the gel coat
application.  The gel coat contains styrene,
polyester resin, and pigment. In Stage  2,
styrene and polyester resin are mixed with
inert fillers and  sprayed onto a previously
prepared mold using a spray gun equipped
with an attachment to add chopped fiber-
glass. Stage 3 includes the addition of fire
retardant fillers  and  precut chipboard and
corrugated  paper  used as structural sup-
ports. In Stage 4, the shower stall or bath-
tub is "pulled" or separated from the mold.

Test Configuration
    Manufacturing processes that involve
the spraying of styrene- based resins have
been identified  as a possible significant
source of volatile organic compound (VOC)
emissions that  may affect human health
and contribute  to the  ozone  non-attain-
ment problem. The mobile pilot unit used
for this test was  configured to treat ap-
proximately 100 cfm (2.8  m3/min) of the
air exhaust  from  a gelcoat spraybooth.
The pilot unit consisted of three reaction

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chambers interconnected using plyvinyl
chloride pipe. The QUAD Chemtact™ pro-
cess  removes  styrene  by  spraying  fine
droplets (a mist) of diluted chemical solu-
tion into a styrene contaminated air stream.
The manufacturer claims that the mist pro-
vides enhanced chemical reactivity  and
provides a large surface area where gas-
liquid phase reactions take place that re-
sult in the removal  of gaseous contami-
nants. Each  reaction chamber was  fed by
a separate  chemical  metering  pump so
that a contaminated air stream could be
treated with  up to three different chemical
solutions as  it passed through the device.
The  styrene is  apparently oxidized  and
absorbed into the scrubber liquor which is
continuously collected  and exhausted
through the  chamber drain. The treated
air is  then exhausted tangentially through
the bottom of the reaction chamber.

Evaluation Results
  Styrene removal  efficiencies  were de-
termined  by  measuring the inlet and outlet
concentration of the test unit using total
hydrocarbon (THC)  analyzers with flame
ionization  detectors (FIDs) and charcoal
adsorption tubes (EPA method 18  and
NIOSH method  1501). The liquid scrubber
did  not achieve styrene removable  effi-
ciencies >55%,  although  a number of ad-
ditives were tried,including sodium hy-
pochlorite, ethylene glycol, sulfuric acid,
methyl ethyl ketone peroxide,  hydrogen
peroxide, and water. The tests were  per-
formed on 3 days (6/22/93 through 6/247
93).  During  the 3 days, 25 separate test
conditions were completed. Costs associ-
ated with  installing  this technology at a
source of styrene emissions were not ad-
dressed due to the failure of the manufac-
turer  to supply  any related  information.
Table 1 contains the inlet and outlet sty-
rene levels and  styrene removal efficiency
for each test conditions.
   In  addition to the evaluation of the liq-
uid  chemical scrubbing  process,  it was
possible to quantify styrene  emissions  in
the spray booth exhaust to which the
chemical scrubber was connected.  These
analyses revealed that styrene was the
only Volatile Organic Compound  (VOC)
with measurable concentrations detected.
   Section 2 of the full  report contains a
detailed description of the facility and sam-
pling  locations, the liquid chemical  scrub-
bing device,  experimental apparatus,  and
experimental methods  and  procedures.
Data, results, and discussion are in Sec-
tion 3. Section  4 contains  the  summary
and  conclusions. The  quality assurance
and quality control measures taken  during
this evaluation  as well as the results  of
these measures  are in Appendix B.
  Samples of spent scrubber liquid were
obtained from Reaction  Chambers 1 and
2 on June  23 and from Reaction Cham-
bers 1,2, and 3 on June 24. On June 23,
only water  was  injected into  Reaction
Chamber 3, so no liquid sample was taken.
In addition, a sample of the process water
used to dilute the chemicals used for scrub-
bing was obtained on June 24. All  liquid
samples were preserved in 250 ml  glass
sample  bottles with Teflon-sealed  caps. It
was originally  intended  to  obtain  more
scrubber liquid  samples. Unfortunately,
because so  many test conditions  were
tried,  it  was difficult to isolate a  set of
operating  conditions  (where reasonable
styrene removal was obtained) that  per-
sisted for a long enough period to obtain
a set of scrubber samples that were not
contaminated  by  additives from a previ-
ous test condition.
  Table 2  gives the results of the analy-
ses carried out on the samples.  The table
shows that styrene  was detected in only
the sample from Reactor Chamber 1  on
June 24. Considering that the liquid scrub-
ber styrene removal efficiency was never
>55% during the time these samples were
taken,  it is  surprising that  styrene was
detected in only one sample.
Table 1.  Inlet and Outlet Styrene Level and Efficiency of Styrene Removal for Each Test Condition
         (6/23/93)
Inlet condition
                     Inlet styrene, ppm
 Outlet styrene, ppm
Efficiency %
1
2
3
4
5
6
7
8
9
10
11
12
13
74.8
82.3
75.6
78.8
80.2
109.9
86.9
95.1
109.0
91.8
85.4
97.3
105.9
41.4
37.7
39.0
40.8
41.2
55.0
41.0
55.1
60.2
52.9
49.9
51.1
48.3
44.7
54.3
48.3
48.1
48.5
50.0
52.8
41.2
44.8
42.3
41.5
47.4
54.5
Table 2.  Results of Analyses Carried Out on Scrubber Liquid Samples and a Process Water Sample
                                                    Concentration    Detection limit
Date Time
6/23 1340


6/24 1040









6/24 1015
Origin
Reaction chamber #1
Reaction chamber #2

Reaction chamber #1




Reaction chamber #2


Reaction chamber #3

Process water
Compound
Chloroform
Acetone
Chloroform
Acetone
Carbon disulfide
2-butanone
Chloroform
Styrene
Acetone
2-Butanone
Chloroform
Acetone
Chloroform
Chloroform
(W/l)
23300
709
39400
1910
104
534000
230
1022
2440
367
1.65
7.41
7.31
55
Bromodichloromethane 12.2
(W/l)
410
364
41
728
280'
1460
82
141
7.28
14.6
0.82
7.28
0.82
0.82
2.37
  Conservative estimate of detection limit based on previous mesurements of similar water samples.

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   L. Felix, R. Merritt, and A. Williamson are with Southern Research Institute, P. O. Box
     55305, Birmingham, AL  35255-5305.
   Bobby E. Daniel is the EPA Project Officer (see below).
   The complete report, entitled "Evaluation of a Liquid Chemical Scrubber System for
     Styrene Removal," (Order No. PB95-XXX XXX/AS;  Cost: $XX.XX; 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:
           Air and Energy Engineering Research Laboratory
           U. S. Environmental Protection Agency
           Research Triangle Park, NC 27711
United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268

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