Control of Volatile Organic Compounds Emissions from Manufacturing

D.3 VAPOR RECOVERY SYSTEM VOC EMISSION TEST DATA^^
On July 14, 1980, Mobil Company collected samples of hydrocarbon
emi ssions from the exhaust vent of the Vapor Recovery/Knockdown System
at its Santa Ana, California polystyrene plant. The samples were
taken using a MDA-808 ~ccuhaler~ pump while velocity was determined
using a ~ u r Model z ~ 441 ai r ve1 oci ty meter. Samples were taken while
the plant was in normal operation. One set of samples was taken while
a vacuum was drawn on dissolver tanks. Another set of samples was
taken while a vacuum was drawn on the flash tank. Both sets of samples
were analyzed for styrene and ethylbenzene by an independnet laboratory.
Computations for emission rates were made based on velocity, sample
volume and sample time. The test results, submitted by the company,
indicate that 0.942 kglday of ethylbenzene and 10.018 kg/day of styrene
are emitted from the exhaust vent of the vapor recovery/knockdown
system. No more information was provided regarding the sampling and
analysis procedure used by Mobil or the laboratory. It is assumed
that standard industri a1 practices were used, thus generati ng valid
estimates of emissions. However, the data should not be used as a
significant basis for emission limitation.
D.4 DISCUSSION OF TEST RESULTS AND THE TECHNICAL BASIS OF THE POLYMERS
AND RESINS VOC EMISSIONS REDUCTION REQUIREMENT
This section discusses test results as well as available theoretical
data and findings on flare and incinerator efficiencies, and presents
the logic and the technical basis behind the choice of the selected
control 1 eve1 .
D.4.1 Discussion of Flare Emission Test Results
The results of the five flare efficiency studies summarized in
Section 3.1.1.1 showed a 98 percent VOC destruction efficiency
except in a few tests with excessive stream, smoking, or sampling
problems. The results of the Joint CMA-EPA study, summarized in
Tab1 e D-2,. confirmed that 98 percent VOC destruction ef fici ency was
achievable for a1 1 tests (i ncludi ng when smoking occurred) except when
steam quenching occurred within the range of flare gas velocities and
heating values tested. Flare gas velocities for the tests reported
to date go up to a high of 18.2 m/s (60 fps) and lower heating values
go as low as 11.2 ~ ~ / m (300 3 Btu/scf). Additional testing is currently