United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
Research Triangle Park NC 27711
EMB Report 80-DRY-9
October 1980
Air
Petroleum Dry Cleaners
Centrifugal Separator
Emission Test Report
Cadet Cleaners
Toronto, Canada
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SOLVENT RECOVERY AND EMISSION CONTROL
PETROLEUM DRY CLEANING INDUSTRY
CADET CLEANERS PLANT
Toronto, Ontario, Canada
Prepared for the
U.S. Environmental Protection Agency
Emission Measurement Branch
Research Triangle Park, N. C. 27711
Prepared by
Clayton Environmental Consultants, Inc
25711 Southfield Road
Southfield, Michigan 48075
EMB Report No. 80-DRY-9
Work Assignment 38
Contract No. 68-02-2817
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TABLE OF CONTENTS
Page
List of Tables i
List of Figures ii
1.0 Introduction 1
2.0 Summary and Discussion of Results 2
3.0 Process Description 11
4.0 Location of Sampling Points 12
5.0 Sampling and Analytical Procedures 14
APPENDICES
A. Esso Chemical Sheet
B. ASTM Methods
B-l. D 322 - 67
B-2. D 240 - 76
B-3. D 96 - 73 and Modifications
C. Laboratory Analysis
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LIST OF TABLES
Table Page
2.1 Results of Filter and Dried Muck 3
Analyses
2.2 Petroleum Solvent Decanted Before 6
Distillation
2.3 Results of Liquid Sample Analyses 8
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LIST OF FIGURES
Figure Page
4.1 Plan view of filtration equipment 13
and location of sampling points
11
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1.0 INTRODUCTION
The United States Environmental Protection Agency
(EPA) retained Clayton Environmental Consultants, Inc. to
evaluate the performance of a centrifugal separator at the
Cadet Cleaners plant in Toronto, Ontario, Canada. The
objective of this study was to determine the total uncon-
trolled solvent loss from this plant (provided by TRW,
Inc.) and to evaluate the performance of the centrifugal
separator as an emission control technique. The results of
this study will be used in research and development efforts
for supporting New Source Performance Standards in the
petroleum dry cleaning industry. This study was commis-
sioned as Project No. 80-DRY-9, Contract No. 68-02-2817,
Work Assignment 38.
The field sampling program, conducted July 9 through
11, 1980, was slightly modified after inception and in-
cluded the following:
(1) Multiple soap and rinse filter muck samples
acquired from diatomaceous earth filters
for petroleum solvent loss determinations;
(2) Multiple dried muck samples acquired from a
centrifugal separator after extraction for
petroleum solvent loss determinations; and,
(3) Duplicate samples from the vacuum petroleum
still bottom wastes, reclaimed distilled
solvents, and a single sample of virgin
petroleum solvent acquired for determina-
tion of Btu content and inerts.
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2.0 SUMMARY AND DISCUSSION OF RESULTS
The results of the sample solvent recovery and heat of
combustion analyses are presented in Tables 2.1 and 2.3,
respectively.
Table 2.1 presents the quantity of solvent (as a
percent by weight) retained by the filter muck samples.
These samples were collected from the East and West domes-
tic soap and rinse filtered mucks, an industrial filtered
muck, both before centrifuqation (after 24 hours of
settling), and from the combined soap and rinse filter
mucks after centrifugation. The efficiency of the
centrifugal separation system also appears. The solvent
retained, as percent by weight, was calculated using the
following equation:
Solvent Retained = (milliliters of diluent) (SpGr) (D) 1QQ
weight of aliquot
where:SpGr = specific gravity of solvent (60/60F)
= 0.7857 (Appendix A)
D = density of water, g/ml
= 1.0
The efficiency of the centrifugal separation system
(quantity of solvent removed, as percent by weight, during
the solvent recovery process) was calculated using the
following equation:
Efficiency = SSF - SDM x 1QO
SSF
where: SSF = % solvent by weight retained by soap
filter.
SDM = % solvent by weight retained by dried
muck.
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TABLE 2.1. RESULTS OF FILTER AND DRIED MUCK ANALYSES
Sampling
Date and Sam
Time
7/09/80 West
PM West
7/10/80 East
AM East
7/10/80 West
PM West
7/11/80 East
AM
7/11/80 West
PM West
(% by Weight)
p e Before Centrifugation
(After 24 hr settling)
soap 47 . 1
rinse 47.6
soap 54.9
rinse 52.3
soap 48.7
rinse 41.3
soap 52.3
soap 51.3
rinse 47.1
Average 49.2
7/11/80 Industrial 52.3
AM
After Centrifugation
34.0
34.0
34.5
34.5
31.4
31.4
38.2
30.9
30.9
33.3
38.2
Extraction
Efficiency
(% by Weight)
27.8
28.6
37.1
34.0
35.5
24.0
27.0
39.8
34.4
32.0
27.0
Facility: Cadet Cleaners, Toronto, Ontario, Canada.
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The solvent retained by the filter muck samples
collected from the domestic soap and rinse filters of the
East and West filtering systems (before centrifugation)
ranged from 41.3 to 54.9-percent, averaging 49.2-percent.
The single industrial filter retained 52.3-percent solvent
by weight. The solvent retained by the dried muck samples,
after centrifugation, ranged from 30.9 to 38.2-percent,
averaging 33.3-percent. Laboratory data appears in Appen-
dix C.
The relative difference in solvent content between the
domestic soap and rinse filter muck samples seems to
generally be a decreasing function. In theory, it is
plausible that the industrial and soap diatomaceous earth
filters separate a coarser dirt particle or a more sponge-
like particle than do the rinse filters and thus, retain
more solvent. However, there are not sufficient data sets
to refute or corroborate this theory.
The centrifugal separator reclaimed an average of
32.0-percent of the solvent in the filters. Therefore, the
solvent loss from the plant is reduced by using the cen-
trifugal separator.
The efficiency of the centrifugal separator seems to
depend on the particle size of the dirt concentration,
solvent retention of the filter mucks to be extracted, and
average rotational speed which the separator ultimately
achieves during extraction. The efficiency of the sep-
arator does not seem to depend on the condition of the
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cloth bag used to retain the dried muck for disposal. This
was evidenced by the fact that the cloth bag was washed and
cleaned prior to the last extraction sampled, yet no sig-
nificant improvement in efficiency was displayed.
Table 2.2 displays the amounts of petroleum solvent
decanted from each filter muck sample (before centrifuga-
tion). Each sample was decanted twice before the lab-
oratory distillation procedure began. The first decanting
occurred in the field after 24 hours or less of settling.
Due to the hazardous/flammable nature of the solvent, field
decanting was necessary to reduce the overall volume of
solvent so the samples could be shipped by land carrier
through customs.
The field decanting removed most of the solvent above
the settled filter muck leaving only a thin layer to keep
the filter muck immersed and fluidized for later laboratory
analysis. This layer of solvent was used by the laboratory
to mix the samples to simulate the 24-hour settling period
prior to distillation analysis which could not be achieved
in the field. This thin layer of solvent was to be de-
canted off by the laboratory after the 24-hour settling
period.
Although five filter muck samples had no excess
solvent to be decanted after the settling period, the
solvent retained by the filter muck dovetailed with those
which did have decantable volumes to within 10.8 and 12.5-
percent of the mean and average values, respectively.
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TABLE 2.2. PETROLEUM SOLVENT DECANTED BEFORE ANALYSES
Sampling
Date and
Time
7/9
PM
7/10
AM
7/10
PM
7/11
AM
7/11
PM
7/11
AM
Sample
West soap
West rinse
East soap
East rinse
West soap
West rinse
East soap
West soap
West rinse
Industrial
Field
Decantation
ml
76
168
120
189
150
120
145
93
98
158
Laboratory
Decantation
ml
28
0
0
0
0
0
27
92
32
65
Total
Volume
ml
104
168
120
189
150
120
172
185
130
223
Facility: Cadet Cleaners, Toronto, Ontario, Canada.
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Table 2.3 presents the heat of combustion of the
liquid samples, expressed as British Thermal Units per
gallon of solvent (Btu/gal), and the percent inerts.
The analyzed heat of combustion of the liquid samples
ranged from 124,900 to 130,400 Btu/gal, with a mean of
128,900 Btu/gal. The still bottom waste samples averaged
130,400 Btu/gal and the reclaimed solvent averaged 127,000
Btu/gal. The still bottom waste has a higher heat value
possibly due to fiber resins and organic constituents
contained therein. It may be feasible to use the still
bottom wastes, now being dumped into the city sewer system,
as a supplemental fuel and/or boiler fuel additive.
The liquid samples were analyzed for percent inerts.
Due to sample contamination of the redistilled and virgin
solvent samples, only the still bottom waste samples were
analyzed and averaged 1.5-percent.
No presurvey was conducted prior to the start of the
project and the scope of the project was expanded in the
field from an original total of six samples to 20 samples.
Due to the brevity of the field sampling schedule (3 days)
and the increase in the number of samples to be collected,
it was necessary to purchase mason jars as extra sample
containers, so as not to further delay the project.
The mason jar lids were fitted with latex rubber
gaskets to insure against leakage. The rubber gaskets on
those sample containers that contained large quantities of
petroleum solvent reacted with the solvent which softened
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TABLE 2.3. RESULTS OF LIQUID SAMPLE ANALYSES
1980
Sample
Date
7/11
7/10
7/11
7/10
7/11
Sample
Virgin solvent
Still bottom waste - 1
Still bottom waste - 2
Average
Dry cleaning solvent - 1
Dry cleaning solvent - 2
Average
Mean
Btu/gal
129,700
130,400
130,400
130,400
129,100
124,900
127,000
128,900
%
Inerts
b
1.4
1.7
1.5
b
b
—
Facility: Cadet Cleaners, Toronto, Ontario, Canada.
^Performed by Detroit Testing Laboratories, Inc., Oak Park, Michigan.
DSamples could not be analyzed due to contamination.
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the seal. The rubber seal did not soften in any of the
dried filter muck sample containers because of the lack of
solvent. The rubber seals on the containers of the filter
muck samples collected before centrifugation, remained
sandwiched between the lid and jar rim even after being
stored for a month prior to analysis. Analysis was delayed
because the glass receiver/traps needed to measure the
diluent during distillationwere on back order by our
laboratory suppliers.
The rubber seals of the precentrifuged sample con-
tainers were not appreciably altered due to the decanting
of solvent in the field; therefore any contamination would
be minimal in lieu of the mass weight of the filters in
comparison to the mass weight of the gasket. Also, the
receiver/trap used in the analysis was only capable of
measuring to the nearest 0.1 milliliter; therefore, the
small amount of rubber seal which might be contained in any
of the mixed 15-grams of the filter muck aliquot would be
negligible. The rubber seals on the virgin and recalimed
solvent sample containers were also softened, causing
portions of the gasket to separate from the main body and
fall into the sample. The virgin solvent developed a very
slight orange hue even after the pieces of the rubber
gasket had been removed from the samples. These samples
were filtered before the heat content analysis (Btu) was
conducted. The contamination from the latex rubber seal,
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which would tend to increase the heat content, would be
very small due to the minimal solubility of latex rubber in
the solvent. The percent inerts were not obtained for
these samples since contamination is a major contributor to
inerts.
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3.0 PROCESS DESCRIPTION AND OPERATIONS
To be supplied by TRW, Inc.
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4.0 LOCATION OF SAMPLING POINTS
All filter muck from the diatomaceous earth filters
is pumped to the centrifugal separator in varied combina-
tions for extraction. The filter muck is delivered to the
top of the centrifugal separator through two radial spout
arms. The samples were collected at the discharge of these
spouts as the muck dropped into the separator.
All dried muck samples were obtained directly from
the centrifugal separator following a 20-25 minute extrac-
tion .
The petroleum still bottom waste samples were col-
lected from the bottom spigot of one 500-gallon per hour
Washex vacuum still. Distilled petroleum solvent samples
were acquired from the distillation collection vessel next
to the still.
The virgin solvent was obtained directly from the
original shipping container. Figure 4.1 presents a plan
view of the equipment and location of sampling points, as
specified.
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J-
Radial spout arms
r
Sewer
trough
11
Diatomaceous Earth Filters
No. 1-10 Domestic
Nos. 11 - 13 Industrial
Leading to City Sewer System
N
Figure 4.1. Plan view of filtration equipment and location of sampling points,
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5.0 SAMPLING AND ANALYTICAL PROCEDURES
SAMPLING PROCEDURES
Characteristic samples of muck were collected from
the soap and rinse filters of the East and West filter
systems. Only one industrial filter sample was collected,
due to equipment malfunctions. The samples were collected
by diverting a portion of each filter muck discharge into a
glass collection container which was washed clean in petro-
leum solvent and dried between each sample collection. Up
to three equal amounts of each sample were proportionately
composited in glass sample bottles.
A representative sample of dried muck was obtained
directly from the centrifugal separator after the comple-
tion of a 20-25 minute extraction. Each extracted muck
sample was composed of up to four filter muck discharges.
A 1-inch (inside diameter) copper pipe was inserted into
the dried muck at random points within the separator to
ensure collection of all layers. A 1-inch (outside dia-
meter) wooden dowel was inserted through the pipe to
deposit the sample in a glass sample bottle. The pipe and
dowel were washed clean in petroleum solvent and dried
between each sample collection.
Two still bottom samples were obtained from one 500-
gallon per hour vacuum still. Because of high temperatures,
the samples were initially collected in a galvanized pail,
and later poured into glass sample bottles.
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Two distilled petroleum solvent samples were obtained
from the vacuum still by directly collecting the solvent in
qlass sample containers.
One virgin petroleum solvent sample was obtained in a
glass sample bottle directly from the original shipping
container.
Therefore, at the end of the study, the following
samples were collected:
3 - West wash filter muck;
3 - West rinse filter muck;
2 - East wash filter muck;
1 - East rinse filter muck;
1 - industrial filter muck;
5 - dried muck;
2 - still bottom waste solvent;
2 - redistilled solvent; and,
1 - virgin petroleum solvent.
For the July 9 and 10 samples, the muck levels were
marked on the sample containers after 24 hours of settling,
and the excess solvent had been decanted off leaving only a
thin layer of solvent covering the muck. The decanting of
the solvent was conducted in-field to comply with the
hazardous/flammable shipping regulations. The settling
times for the July llth morning and afternoon samples were
6-hours and 2-hours, respectively. The volume of solvents
decanted in the field were recorded. The containers were
sealed and taped to prevent leakage while being shipped to
the laboratory for analyses.
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LABORATORY ANALYSIS
All samples were checked for leakage and/or breakage
upon receipt in the laboratory and none was detected.
Each filter muck sample was thoroughly mixed with the
remaining petroleum solvent in its container using a stain-
less steel stirring rod. The samples were allowed to
settle for 24 hours and any excess solvent was decanted off
and the volume recorded.
To determine the solvent content in the muck (percent
by weight), representative portions (approximately 15-
grams) were taken from both the filter muck and dried muck
samples with a clean glass tube. The withdrawn portion was
weighed to the nearest 0.01-gram, transferred with dis-
tilled water to a distillation flask which was heated with
an electric heater, and analyzed by following the refluxing
procedure as described by the American Society for Testing
and Materials (ASTM) Method D 322-67 (Appendix B-l). When
heating/condensation began, the system was rechecked to
ensure proper functioning. Refluxing was allowed to pro-
ceed for 2 hours, after which, the volume of diluent was
measured at one-half hour intervals. The analysis was
considered complete when volume changes no longer occurred
at the set refluxing temperature.
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The still bottom wastes, the redistilled solvent, and
the virgin solvent were analyzed for Btu content and inerts
by Detroit Testing Laboratory, Inc. Btu content was deter-
mined according to the procedures outlined in ASTM Method D
240-76 (Appendix B-2). Prefiltering of the virgin and
redistilled solvent samples removed any residue from the
samples before Btu analyses. The procedures in ASTM Method
D 96-73 were modified in the analysis for inerts. Both the
method and modifications are presented in Appendix B-3.
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