S-EPA
United States
Environmental Protection
Agency
Industrial Environmental Research
Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S2-81-072 Oct. 1981
Project Summary
Evaluation of Solvent
Loss from Vapor Degreaser
Systems Phases 2 and 3:
Effect of Crosscurrent Air
Velocity on Control System
Performance
R. W. Gerstle and E. S. Schindler
*
The U.S. Environmental Protection
Agency (EPA) initiated a research
program to evaluate the solvent loss
reduction capabilities of various de-
greaser modifications, controls, and
operating practices of open-top vapor
degreasers. PEDCo Environmental,
Inc., was contracted to carry out the
research program. The American Soci-
ety for Testing and Materials (ASTM)
was asked to assist EPA in defining
and formulating the test program and
reviewing its progress. A special
ASTM subcommittee of Committee
D-26 on degreasers was established
for this purpose.
This Project Summary was devel-
oped by EPA's Industrial Environmen-
tal Research Laboratory, Cincinnati,
OH, 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 and Summary
The program began witruhe writing
of a detailed test plan, which was
.submitted to EPA for technical review.
The plan provided details of tests, test
location, types of solvents, variables and
control modifications to be tested,
parameters to be measured, and test
procedures. The results of these tests
referred to as Phase 1 were presented in
the report "Evaluation of Solvent Loss
from Vapor Degreaser Systems," No-
vember 1980.
Phase 1 quantified the ability of a
control device to reduce solvent loss
from a job-shop-size degreaser at the
ideal operating conditions suggested by
the manufacturer and EPA. It also tested
the effect of non-ideal operating con-
ditions on solvent loss, but did not
quantify the effectiveness of control
devices operating at non-ideal condi-
tions. The test data showed, however,
that a slight draft across the lip of the
degreaser increased solvent loss dra-
matically. On the basis of this increase,
the EPA decided that control devices
should be evaluated for the ability to
control solvent loss at high cross-
current air velocities: 0.67 m/s (132
ft/min)and 1.12 m/s (220 ft/min).
Phase 2 comprised the supplemental
tests that were performed to supply the
previous evaluation. Tests were also
conducted to supplement the Phase 1
data about variations in hoist speed.
Some Phase 2 results were unusual.
Although the refrigerated freeboard
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chiller (RFC) substantially reduced sol-
vent loss when methylene chloride (MC)
was used, it substantially increased
solvent loss when 1,1,1 -trichloroethane
(TE) was used. Further, Phase 2 results
indicated that changing the freeboard
ratio (FR) reduced solvent loss only
slightly, regardless of solvent. Phase 3
was, therefore, conducted to re-verify
the Phase 2 results, further examine the
-interaction of air velocity, RFC, and FR,
and to explain the anomalies experi-
enced in the Phase 2 testing.
A separate set of plant site evalua-
tions were also conducted to characterize
the cross-current velocities that typically
are found in industrial sites. Seven
plants were evaluated which included a
broad range of industrial functions from
aircraft manufacturers to heavy ma-
chinery manufacturing to small and
large appliance manufacturing. The
typical average cross-current velocity
was found to be approximately .445
m/s (87.6 ft/min). Thus, the typical
plant's cross-current draft characteristics
were found to be within the boundary of
this experimental program.
Conclusions
The conclusions that were developed
from the program characterizes and
quantifies the effectiveness of various
control options for vapor degreasers.
Those conclusions, when combined
with Phase 1 test results, are summa-
rized below.
• An increase in cross-current veloc-
ity will increase solvent emission
rates from open top vapor de-
greasers. A 40 percent increase in
emissions is predicted at .67 m/sec
over calm conditions. The typical
plant draft conditions were within
the draft conditions of this research
program. Thus, the emission rates
determined during the program are
typical of those which would be
experienced in an industrial facility.
Increased freeboard ratios will
reduce emission rates. Increasing
freeboard from .50 to .75 will de-
crease emissions by 40 percent in
some cases. Additional incremental
reductions are achievable as the
freeboard is increased above .75.
Refrigerated freeboard chillers will
reduce emission rates when used
either by themselves or in combi-
nation with other control options.
Control effects of greater than 40
percent are possible under some
conditions.
• Automatic lids can assist in the
reduction of solvent emission rates.
Test indicated that the use of an
automatic lid can reduce solvent
loss by greater than 50 percent in
some instances.
The best emission reduction technique
was found to be the minimization of
cross-current drafts at the lip of the
degreaser. However, some operational
constraints may prevent the lowering of
air velocity. Other solvent reduction
options, as previously indicated, were
also found to be effective in reducing
solvent loss.
R. W. Gerstle and E. S. Schindler are with PEDCo Environmental. Inc.. Cincin
nati. OH 45246.
Charles H. Darvin is the EPA Project Officer (see below).
The complete repoit. entitled "Evaluation of Solvent Loss from Vapor Degreaser
Systems Phases 2 and 3: Effect ofCrosscurrent Air Velocity on Control System
Performance," fOrder No. PB 81-246 308; Cost: $9.50, 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
Cincinnati. OH 45268
if U S GOVERNMENT PRINTING OFFICE, 1981 — 559-017/7364
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
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