United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
Research Triangle Park NC 27711
EMB Report 80-BYC-6
March 1981
Air
Benzene
Coke Oven By-Product
Plants
Emission Test Report
CF&I Steel Corporation
Pueblo, Colorado
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SET 1957 08 0181
BENZENE SAMPLING PROGRAM
AT COKE BY-PRODUCT RECOVERY PLANTS:
CF AND I STEEL CORPORATION
PUEBLO, COLORADO
EPA Contract 68-02-2813
Work Assignment 48
ESED Project No. 74/4j
Prepared For:
Mr. Daniel Bivins
U.S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Emission Measurement Branch, ESED, MD-13
Research Triangle Park, North Carolina 27711
March 1981
SCOTT ENVIRONMENTAL SERVICES
A Division Of
SCOTT ENVIRONMENTAL TECHNOLOGY, INC.
Plumsteadville, Pennsylvania 18949
Scott Environmental Technology Inc.
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TABLE OF CONTENTS
Page
1.0 INTRODUCTION 1-1
2.0 SUMMARY OF RESULTS 2-1
3.0 RESULTS AND DISCUSSION 3-1
3.1 COOLING TOWER-TAR BOTTOM FINAL COOLER . . 3-1
3.2 .TAR STORAGE TANK 3-3
4.0 PROCESS DESCRIPTIONS 4-1
5.0 FIELD SAMPLING AND ANALYSIS METHODOLOGY 5-1
5.1 DETERMINATION OF BENZENE FROM STATIONARY SOURCES: EPA METHOD
110 AND MODIFICATIONS 5-1
5.2 SAMPLE HANDLING 5-4
5.3 FIELD ANALYSIS 5-4
6.0 FIELD SAMPLING PROCEDURES 6-1
6.1 COOLING TOWER 6-1
6.2 TAR STORAGE TANK 6-3
7.0 LABORATORY SAMPLE ANALYSIS 7-1
7.1 SAMPLE PREPARATION 7-1
7.2 PURGE AND TRAP PROCEDURE FOR EXTRACTION OF BENZENE FROM
LIQUID PHASE TO GASEOUS PHASE 7-2
7.3 GAS CHROMATOGRAPH 7-4
8.0 QUALITY CONTROL AND QUALITY ASSURANCE 8-1
8.1 FIELD ANALYSIS PROCEDURES ... 8-1
8.2 PROCEDURES FOR ANALYSIS OF PROCESS LIQUIDS 8-2
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SET 1957 08 0181
Page 1-1
1.0 INTRODUCTION
Scott Environmental Services, a division of Scott Environmental
Technology, Inc., conducted a sampling program at CF and I Steel Corporation
in Pueblo, Colorado to determine benzene emissions from two sources in the
coke by-product recovery plant. The work was performed for the United
States Environmental Protection Agency, Emission Measurement Branch, under
Contract Number 68-02-2813, Work Assignment 48. CF & I was one of seven
coke plants visited to collect data for a possible National Emission
Standard for Hazardous Air Pollutants for benzene.
Sampling was conducted at CF and I on October 6th and 7th, 1980.
Air and liquid samples for benzene analysis were collected from the tar
storage tank and the cooling tower tar bottom final cooler.
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SET 1957 08 0181
Page 2-1
2.0 SUMMARY OF RESULTS
Benzene Emission Rate;
Process
Tar Storage Tank
Cooling Tower-Tar Bottom
Final Cooler
Ib/hr
2.2
11.9
kg/hr
1.00
5.40
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SET 1957 08 0181 Page 3-1
3.0 RESULTS AND DISCUSSION
3.1 COOLING TOWER-TAR BOTTOM FINAL COOLER
Water from the tar bottom final cooler is collected in a "hot
well" and then circulated over an atmospheric cooling tower. The tower
has a 20 foot diameter fan on top that draws air upward countercurrent to
the falling water to effect the cooling. The tower also acts as a stripper
for benzene contained in the hot water.
Three Method 110 runs were performed on the cooling tower with
an average result of 11.9 Ib/hr benzene. Table 3-1 presents the results
of the tests. A 24-point sampling and velocity traverse at two minutes
per point was made across two diameters of the 20 foot fan shroud to obtain
an integrated sample.
Liquid samples were dipped from the hot well and cold well, with
temperatures of 96°F and 78°F respectively. Benzene concentrations; were
approximately 68 ppm in the hot well and 7.5 ppm in the cold well.
All stack flow rates were corrected to the average conditions at
which the benzene concentrations were measured in the Tedlar bags; assumed
to be saturated at 68°F and 29.92 inches of Hg.(2 1/2 % moisture). Example
calculations are shown in Appendix A.
Scott Environmental Technology Inc.
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£2| TABLE 3-1
X* COOLING TOWER DATA SUMMARY
3
C1 Process Cooling Tower-Tar Bottom Final Cooler
3 Plant CF&I, Pueblo, Colorado
1
^ Stack Barometric
3^ Run Sample Temp. Pressure
=j" No. Date Period (°F) (in. Hg)
& I 10/7/80 0855-0955 71 25.48
8 2 10/7/80 1005-1100 70 25.47
3 10/7/80 1102-1155 74 25.45
Liquid Sample Data Summary
Sample Location Date Time
Hot Well 10/7/80 1210
Cold Well 10/7/80 1140
St-anHai-H HnnrH t-i one? Sal-iiral-f»rl at- fift°T? 7Q Q? Inrh
Stack Diameter 20 ft.
Stack Area 314 ft2
Flow Rate Flow Rate
Stack Stack Standard Benzene
Velocity Conditions Conditions Concentration
(ft/min) (ACFM) (SCFM) (ppm)
1430 449,000 407,000 2.50
1440 452,000 384,000 2.38
1780 559,000 470,000 2.17
Avg.
Sample Benzene Cone.
Temp (°F) (ppm by weight)
96 38.2
51.9 . ,. .
,,,- , Average 68.4
78 4.1
8 9
Q*, Average 7,5
y . ^
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t->
Benzene
Emission
Rate
(Ib/hr)
12.3
; 11.1
12.f4
11.9
ppm
ppm ^
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SET 1957 08 0181 Page 3-3 ; '.
3-2 TAR STORAGE TANK
Tar from the decanter is pumped to the heated tar storage tank,
which is open to the atmosphere and serves as a dehydrator'. Benzene and
other impurities contained in the tar are potentially released along with
the water.
The measured benzene emissions from,the tar storage tank ranged
from 1.6 Ib/hr to 2.7 Ib/hr, with an average result of 2.2 Ib/hr. The
test results are presented in Table 3-2.
The tar in the tank had a surface temperature of 145°F and the
three liquid samples dipped from the tank had benzene concentrations of
6 ppm, 17 ppm and 75 ppm. There were considerable differences in the
apparent viscosities of the three samples, which accounts for the variation
in the analysis results.
Scott Environmental Technology Inc.
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y"S, TABLE 3-2
TAR STORAGE DATA SUMMARY
3 Process Tar Storage Tank #5
m
-• Plant CF&I, Pueblo, Colorado
1
gj- Stack Barometric
. Run. Sample Temp. Pressure
?F No. Date Period (°F) (in. Hg)
8- 1 10/7/80 1415-1445 121 25.39
"=• 2 10/7/80 1520-1550 119 25.39
3 10/7/80 1600-1630 113 25.39
Liquid Sample Data
Sample Location Date Time
Tar Storage Tank - 10/7/80 1700
Dipped From Top
Stack Diameter
Stack Area
Flow Rate
Stack Stack
Velocity Conditions
(ft/min) (ACFM)
150 430
150 430
120 350
Sample
Temp (°F)
145
23"
2.9 ft2
Flow Rate
Standard Benzene
Conditions Concentration
(SCFM) (ppm)
300 622
310 730
240 539
Avg.
Benzene Cone.
(ppm by weight)
16.8
75.4
6.2
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Benzene
Emission
Rate
(Ib/hr)
2.3
2.7
1.6
2.2
Standard Conditions: Saturated at 68°F, 29.92 inches Hg
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SET 1957 08 0181 Page 4-1
4.0 PROCESS DESCRIPTIONS
Management of CF&I Steel Corporation has requested that l:he
descriptions prepared for their processes be regarded as proprietary.
They are filed in the confidential files maintained by the Emissions
Standards and Engineering Division of the Environmental Protection Agency.
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Page 5-1
SET 1957 ,08 0181
5.0 FIELD SAMPLING AND ANALYSIS METHODOLOGY
5.1 DETERMINATION OF BENZENE FROM STATIONARY SOURCES:
EPA METHOD 110 AND MODIFICATIONS
EPA Method 110 consists of drawing a time-integrated stack gas
sample through a probe into a Tedlar* sample bag, which is enclosed in a
leak-free drum, by use of a pump hooked to the drum outlet which slowly
evacuates the drum, causing the bag to fill. A copy of the method is
included in Appendix D.
The method was modified by Scott because as it stands the
method doesn't account for moisture in the sample stream, and is only
designed to measure benzene concentration, not mass emission rate. The
following modifications were made to all tests done using Method 110:
1. To obtain mass emission rates, velocity and temperature
readings were taken at the top of the stack at 5 minute intervals during
the 30-minute sampling runs. This information was used to calculate flow-
rate, which was used in conjunction with the benzene concentration to
yield the mass emission rate. Velocity readings were made using a vane
anemometer with direct electronic readout.
2. A personnel sampling pump was substituted for the pump,
needle valve, and flowmeter of the method. The personnel pumps have
built-in flowmeters and rate adjustment screws and have the further
advantage of being intrinsically safe, as required in many areas of
the coke plant.
* Mention of trade names or specific products does not constitute endorsement
by the U.S. Environmental Protection Agency.
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Page 5-2
SET 1957 .OS 0181
3. Swagelok fittings were used in place of quick-connects.
4. Rather than discarding Teflon sample lines after each set
of samples, they were washed with propylene carbonate and/or acetone and
flushed with nitrogen before reuse.
5. An orifice and magnehelic gauge were inserted in the sampling
line before the Tedlar bag to indicate that air flow was reaching the
bag.
6. A water knockout trap was inserted between the probe and
magnehelic gauge to collect any condensate in the sample line.
7. The following cleanup procedures were followed:
If any condensate was collected in the trap or sample line, it
was measured and saved for analysis. The probe, line and trap were then
washed with propylene carbonate, which was also saved for analysis. Any
benzene found in these washes and water catches was added to the total found
in the sample bag to determine mass emission rates.
Bag volumes were measured whenever water was collected in the
trap by emptying the bag through a dry gas meter after the sample was
analyzed. The volume of water collected in the trap was then converted
to an equivalent air volume and was added to the volume in the bag to
determine the percent moisture in the sample stream.
After the probe, line and trap washes were completed, the lines
were washed with acetone to remove the propylene carbonate film and flushed
with nitrogen to dry.
Figure 5-1 shows the modified Method 110 setup.
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SET 1957 08 0181
Page 5-3
FIGURE.5-1
ST>K:/C-*
TANK
Inc.
MODIFIED METHOD 110
SAMPLING TRAIN
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SET 1957 0&- 0181 Page 5-4
5.2. SAMPLE HANDLING
After being collected the gas samples were immediately
transported to the gas chromatograph and analyzed. The elapsed time
between sample collection and analysis never exceeded one hour.
To verify that there was no sample degradation in samples of this type
some of the samples were retained for 24 hours and reanalyzed. The
loss of benzene and isobutane observed was typically less than 5%.
5.3 FIELD ANALYSIS
All gas samples collected were analyzed using a Shimadzu
GC Mini 1 gas chromatograph equipped with dual flame ionization
detectors, dual electrometers, heated sample loop and a backflush
system. Figure 5-2 shows a schematic of the backflush apparatus.
The backflush system is composed xjf a ten port sequence reversal valve
and two columns, a scrubber column for retaining high molecular weight
compounds and an analytical column. When the system is in the inject
mode the scrubber column and the analytical column are connected in
series allowing sample components to move from the precolumn to the
analytical column. In the backflush mode the columns are disconnected
from each other and become two separate systems each with its own
carrier gas source. This arrangement allows the separation and measure-
ment of low molecular weight compounds while the scrubber column is
being backflushed of heavier sample components. Backflush times for
different mixtures of sample components must be predetermined to insure
i
that the compound(s) of interest are transferred to the analytical
column before backflushing is started.
Scott Environmental Technology Inc.
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W
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A >
CARRIER GAS A
PREP, COLUMN
SAMPLE INJECTION
CARRIER GAS B
VO
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ANALYTICAL COLUMN
DETECTOR
INJECT
A, D, E OPEN
B, C CLOSED
BACKFLUSH
A, E CLOSED
B, C, D OPEN
00
ft)
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GC COLUMN CONFIGURATION WITH BACKFLUSH
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SET 1957 08. 0181
Page 5-6
Samples for chromatographic analysis were drawn into a 20
cc glass syringe then introduced to the sample loop inlet. The
samples once in the sample loop were allowed to come to atmospheric
pressure by waiting 15 seconds prior to injection. The following
chromatographic conditions were maintained:
Column Temperature (isothermal) , - 100 C
Injector and Detector Temperature - 200 C
5 ml Sample Loop, Temperature
Carrier Gas Flow Rate
Hydrogen Flow. Rate
Air Flow Rate
Analysis Time
Detector
- 50°C
- 32 cc/min.
- 40 cc/min.
- 240 cc/min.
- 5 min.
- Flame lonization
The columns used for field analysis were:
A - Scrubber Column
10% FFAP on Supelcoport 80/100
1/8" x 1 m Stainless Steel
B - Analytical Column
20% SP-2100, 0.1% Carbowax 1500
100/120 Supelcoport
1/8" x 10' Stainless Steel.
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SET 1957 08 0181 Page 6-1
6.0 FIELD SAMPLING PROCEDURES
6.1 COOLING TOWER
The cooling tower at CF&I is about 16 feet high and has & 20-foot
diameter fan on top surrounded by a 6 foot high shroud. The fan is located
about 2 feet below the top of the shroud, as shown in Figure 6-1.
Sampling was conducted in accordance with EPA Method 110,,
modified as described in Section 5.1, and utilizing a 24-point sampling
and velocity traverse to obtain an integrated sample and an accurate
velocity profile. The sampling time at each traverse point was two
minutes.
Liquid samples were extracted from the hot and cold wells using
an aluminum can on a rope. Amber glass bottles were then filled from the
can and sealed with Teflon-lined caps, and the samples were returned to
Scott's laboratory for analysis.
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SET 1957 08 0181
Page 6-2
FAN DRIVE'
PLA-N VIEW
LADDER
•3uO'
SHROUD
HEIGHT
G,'
FAN LEVEL
33'
SIDE V/EW
Scott
Environmental
Technology
Inc.
FIGURE 6-1 COOLING TOWER-TAR BOTTOM FINAL COOLER
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SET 1957 08 0181 Page 6~3
6.2 TAR STORAGE TANK
There are two tar storage tanks at CF&I, separated by a flushing
liquor holding tank. The tar tanks are used alternately for tar storage and
tar dewataring. During our visit the east tank was in operation as a
dewatering tank and the sampling was conducted, on this tank, depicted in
Figure 6-2.
The tank has an open elliptical vent on top at deck level, and
an open crack in the deck surface. The Scott sampling crew plugged the
crack during sampling and constructed a sheet metal stack approximately .
4 feet high around the elliptical vent to facilitate sampling and
measuring velocity.
Three Method 110 tests were run on the tar storage tank, followed
by two moisture determination tests using tared silica gel tubes hooked
to a dry gas meter and pump. The average result of the moisture tests
was 13.75% which indicates that the sample stream was saturated at stack
temperature, which was 120°F.
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SET 1957 08 0181
Page 6-4
160,000 GALLON
STORAGE TANK
STACK
EXTENTION
3&QD. PIPE
OPEN HOLE
TEST PT.
WALK
LADDER
•TESTPOR7
Scott
Environmental
Technology
Inc.
FIGURE 6-2 TAR STORAGE TANK
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SET 1957 08 .0181 "- Page 7-1
7.0 LABORATORY SAMPLE ANALYSIS
Two types of liquid samples were collected: process liquids, and
sample line and water trap catches and washes. All liquid samples were
stored in amber glass bottles and returned to Scott's Plumsteadville laboratory
for analysis.
7.1 SAMPLE PREPARATION
Depending upon the complexity of the sample, one of the following
sample preparation procedures was followed prior to the "purge and trap"
procedure and analysis.
Samples Containing Immiscible Liquid Phases
Using a clinical centrifuge (International Equipment Company,
Massachusetts) immiscible liquid phases were separated and each phase was
analyzed separately for benzene.
Samples Containing Solid and Immiscible Liquid Phases
Samples containing solids of higher density than the liquid phase
were separated by centrifuge or by simple decantation of the liquid. The
different phases in the liquid fraction were then further separated by
centrifuging. Solid and liquid phases were analyzed separately.
Samples Containing Finely Crystalline Solid Suspension
In analyzing these samples the stoppered sample jars were shaken
for at least half an hour for homogenizing the solution. The uniform
distribution of suspended fine crystalline solid particles was tested by
determining the percentage of dry solid in several aliquots of the homoge-
nized mixture. A weighed amount of the mixture was analyzed for besnzene.
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SET 1957 08. 0181 Page 7-2
Sampling System Washings
All washings were clear solutions having only one liquid phase.
The total weight, of the liquid phase was determined using a balance correct
to ±0.1 g. The total weight of each washing wes more than 25 grams, so an
error of 0.1 g in weighing the mass will contribute an error of only 0.4%
to the final analytical data. A weighed aliquot of the washing was analyzed
for benzene by following the "purge and trap" and analysis procedures out-
lined in the following sections, and using this analysis data the. weight
of benzene present in the total mass of washing was calculated. .
7.2 PURGE AND TRAP PROCEDURE FOR EXTRACTION OF BENZENE FROM LIQUID PHASE
TO GA.SEOUS PHASE
An accurately weighed quantity of the sample to be analyzed was
diluted with 20-25 ml of propylene carbonate in a specially designed glass
purging apparatus which was kept immersed in a thermostatted water bath
maintained at 78°C. Benzene free nitrogen gas was bubbled through the
propylene carbonate solution in the purging apparatus at the rate of
0.2 - 0.3 liters/minute, and collected in leak free Tedlar bags. Under
these experimental conditions, 1 1/2 - 2 hours were sufficient to purge
off all the benzene from the liquid phase to the gaseous phase. The total
volume of nitrogen gas used to purge the sample was accurately measured
by a calibrated dry gas meter. A diagram of the purge and trap set-up is
shown in Figure 7-rl.
Propylene carbonate was found to be an ideal diluting solvent
for the extraction of benzene from all types of liquid samples containing
viscous tar, pitch, light and heavy oil and insoluble particulates. It
t
was chosen for its high boiling point, low density, and good solvating
capacity.
Scott Environmental Techndosy '"C-
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HITR06EH
CYLINDER. -
GAUGE.
oar GAS
>
i
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1
C I A V^L/, 1*1 ET E R —
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THERMOMETER-
1
0
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en
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FIGURE 7-1 PURGE AND TRAP METHOD EQUIPMENT SET-UP
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SET 1957 08 0181 . Page 7-4
7.3 GAS CHROMATOGRAPH
A Perkin-Elmer 900 gas chromatograph was used for the analysis
of the purge bags. A 10 ft. by 1/8 inch stainless steel column packed with
20% SP-2100/Oil% Carbowax 1500 on 80/120 mesh Supelcoport was used for the
analysis. This column gave complete resolution of the benzene peak from
other components present in the purge bags. The 'peak height' method was
utilized to calculate the concentration of benzene in the purge bags
analyzed. The Perkin-Elmer 900 used for analysis was not equipped with
a backflushing unit. Gas chromatograph conditions were as follows:
GC column temperature: 70°C isothermal
Detector temperature: 190°C
5 ml loop at a temperature of 120°C
Carrier gas flow rate: 30 cc/min He
Hydrogen flow rate: 45 cc/min
Oxygen flow rate: 400 cc/min
Detector: Flame lonization Detector (FID)
In addition to benzene, the purge bags contained other volatile
hydrocarbons present in the liquid samples such as toluene and naphthalene.
Because this chromatograph was not equipped with a backflush, it was
necessary to elute all heavy organics from the column by heating the column
to 150°C after every two injections for one hour with the carrier gas on.
After cooling the column to 70°C the absence of any organic in the column
which might overlap the benzene peak in the next analysis was checked. When
the column was found to be satisfactorily clean, the next analysis was
continued under the conditions previously described.
Scott Environmental Techndosy Inc
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SET 1957 08 0181 Pa8« S"1
8.0 QUALITY CONTROL AND QUALITY ASSURANCE
The following sections will address quality control and quality
assurance procedures for the field analysis of benzene in air samples and
the laboratory analysis of process liquids and BaP samples.
8.1 FIELD ANALYSIS PROCEDURES
All samples were analyzed in duplicate and as a rule peak heights
were reproduced to within 5%. For some very high concentration samples
(percent range) it was necessary to make dilutions for analysis. When this
was done a fresh dilution was prepared for each injection and peak heights
were reproduced to within 10%. To verify that the system was retaining no
benzene, frequent injections of the standard and nitrogen were made. In all
cases the result was satisfactory.
The Tedlar bags that were reused for sampling were flushed three
times with nitrogen and allowed to sit overnight after being filled to
approximately three quarters of their capacity. They were, analyzed for
benzene content the following day. The background concentrations of the
bags were recorded and varied from 0 to 10 ppm benzene. Care was taken to
use sample bags whose background concentration was very low compared to the
expected concentration of the source.
The accuracy and linearity of the gas chromatographic techniques
used in this program were tested through the use of EPA Audit Samples. Two
standards, a 122.5 ppm and 6.11 ppm benzene were used to analyze the audit
cylinders.
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SET 1957 08 0181 Page 8-2
8.2 PROCEDURES FOR ANALYSIS OF PROCESS LIQUIDS
Scott's benzene standards, checked against EPA Audit Standards,
were used as reference standards throughout this program. The accuracy and
linearity of the gas chromatographic technique for benzene analysis was
tested through the use of EPA Audit Standards which were available to Scott.
Gas chromatographic analysis of the samples and standard were performed
under identical conditions to assure the accuracy of the analytical data
generated.
Each batch of propylene carbonate which was used as the diluting
solvent in the purge and trap technique was analyzed for benzene content by
subjecting 25 ml of propylene carbonate to the purge and trap procedure
followed by gas chromatographic analysis of the trapped gas under identical
conditions as described in Section 5.2. All batches of analytical grade
propylene carbonate were found to be free from benzene.
Every day before the analysis of samples the purging appeiratus and
trapping bags were tested for absence of benzene. Whenever the whole system
was found to be free from benzene to the lowest detectable limit of the
instrument, the samples were analyzed using the purging apparatus and the
trapping gas sampling bags.
Generally an accurately weighed mass of each sample was subjected
to purge and trap procedure only once and the trapped gas sample was repeat-
edly analyzed by GC until the analytical data of consecutive GC analyses varied
by ±0.5% or less.
Scott Envwonmentanechnolpgy Inc
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SET 1957 08- 0181 ' " Pa§e 8~3
For randomly selected samples, the whole analytical procedure was
repeated with a different weighed mass of the source sample to check the
validity and accuracy of the analytical methodology. The analytical data
for different runs were found not to vary by more than 5%.
By purging the sample with nitrogen under the experimental con-
ditions as utilized by Scott, the recovery of benzene from the sample was
quantitative and this has been verified by analyzing a standard benzene
solution in propylene carbonate containing tar and pitch.
Scott Environmental Technology Inc.
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