&EPA
United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
RTF, NC 27711
EMB Report 88-CEP-14
SEPTEMBER 1988
Air
CHROMIUM
ELECTROPLATERS
TEST REPORT
PRECISION MACHINE
AND HYDRAULICS
WORTHINGTON,
WEST VIRGINIA
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EPA Contract No. 68-02-4346
Work Assignment 4
February 7, 1989
Final Report
Determination of the Efficiency of a
Mesh-Pad Mist Eliminator
Candidate Plant
Precision Machine and Hydraulics, Inc.
Worthington, West Virginia
Prepared for
U.S. Environmental Protection Agency
Emissions Measurement Branch
Research Triangle Park, North Carolina 27711
Prepared by
PEER Consultants, P.C.
4134 Linden Ave., Suite 202
Dayton, Ohio 45432
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DISCLAIMER
This report has been reviewed by the U.S. EPA Office of Air Quality Planning
and Standards and approved for publication. Mention of trade names or commercial
products is not intended to constitute endrosement or recomendation for use.
n
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CONTENTS
Section Page
1.0 Introduction 1
2.0 Process Operation 3
3.0 Summary of Results 10
4.0 Sampling Locations and Test Methods 24
5.0 Quality Assurance 29
111
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FIGURES
Figures Page
1-1 Location of sample points 2
2-1 Side view of capture and control system at
Precision Machine and Hydraulic, Inc.,
Worthington, Nest Virginia 4
2-2 Cross-sectional view of mesh-pad mist eliminator at
Precision Machine and Hydraulic, Inc.,
Worthington, West Virginia 6
TABLES
Table Page
2-1 Average Operating Parameters During
Mass Emission Tests 8
2-2 Total Current Supplied to Plating Tank During
Mass Emission Tests 9
3-1 Schedule of Activities 11
3-2 Summary of Flue Gas Conditions 13
3-3 Summary of Sample Volumes, Analytical Results
and Emission Rates for the Mesh-Pad Mist
Eliminator Inlet 14
3-4 Summary of Sample Volumes, Analytical Results and
Emission Rates for the Mesh-Pad Mist
Eliminator Outlet 16
3-5 Summary of Cr+6 Removal Efficiencies
17
3-6 Summary of Plating Solution Analytical Results 18
3-7 Inlet Screening Method Results 22
iv
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TABLES (continued)
Table Page
3-8 Outlet Screening Method Results 23
4-1 Sample Traverse Point Locations for the Mesh-Pad
Mist Eliminator Inlet and Outlet 25
5-1 Summary of Analytical Results for QA/QC
Samples and Blanks 31
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SECTION 1.0
INTRODUCTION
During the week of September 19, 1988, an emission measurement
program was conducted at the Precision Machine and Hydraulics, Inc.,
plant in Worthington, Nest Virginia. The primary purpose of this program
was to collect data to determine the efficiency of a mesh-pad mist
eliminator. Based on this determination, it may be necessary to develop
a regulatory alternative for this type of system.
The principal reason for selecting Precision Machine and Hydraulic
was the plant's use of a mesh-pad mist eliminator containing two mesh
pads to control chromic acid emissions from a plating tank. The capture
and control system on the plating tank consists of a single-sided lateral
hood ducted to the mesh-pad mist eliminator prior to ducting to the
atmosphere. In order to assess the control efficiency of the system,
hexavalent chromium (Cr*6) emissions were measured at two locations
along the duct. These locations are identified in Figure 1-1 as:
1) inlet to the mesh-pad mist eliminator and 2) outlet from the mesh-pad
mist eliminator.
The emission samples were collected using the Modified Method 13B
(MM13B) sample train. This method will be discussed in Section 4.0.
The samples were analyzed for Cr+s concentration using the
diphenylcarbazide colorimetric method. This method will also be
discussed later in Section 4.0.
The test was planned and conducted by the U.S. EPA, Emission
Measurement Branch located in Research Triangle Park, North Carolina.
Midwest Research Institute located in Raleigh, North Carolina was
responsible for monitoring the process operation, and PEER Consultants,
P.C., located in Dayton, Ohio provided analytical support and was
responsible for the preparation of draft and final reports.
1
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2. Outlet location
Fan
I
I
I
-Lr
I
i
I
I
h-
_J
Inlet location
Mist Eliminator
S
Plating Tank
Figure 1.1. location of- sample points.
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SECTION 2.0
. PROCESS OPERATION
2.1 PROCESS DESCRIPTION
Precision Machine and Hydraulics, Inc. 1s a small job shop
specializing 1n precision finishing of hydraulic cylinders. The plant
currently operates one hard chromium plating tank. The tank 1s used to
plate hydraulic cylinders which range In size from 5.1 to 28 cm (2.0 to
11.0 1n) 1n diameter and 0.6 to 2.4 m (2.0 to 8.0 ft) 1n length. The
plating tank operates approximately 8 hours/day, 5 days/week. Typical
plating times range from 1.5 to 15.0 hours. Cylinders plated for more
than 8 hours are plated over a 2-day period.
The plating tank 1s 2.4 m (8.0 ft) long, 0.76 m (2.5 ft) wide, and
2.7 m (9.0 ft) deep, and holds approximately 4,810 a (1,270 gal) of
plating solution. The plating solution contains chromic add 1n a
concentration of about 210 g/fi. (28 oz/gal) of water. Sulfurlc add 1s
used as a catalyst at a bath concentration of 2.1 g/ft, (0.28 oz/gal).
The temperature of the plating solution 1s maintained at about 54°C
(130°F). The tank Is divided Into two plating cells. Each plating cell
1s equipped with a rectifier. The typical current and voltage applied to
each cell ranges from 2,500 to 3,000 amperes and from 4.5 to 6.0 volts,
respectively.
2.2 AIR POLLUTION CONTROL
The capture and control system on the plating tank consists of a
single-sided lateral hood ducted to a mesh-pad mist eliminator.
Figure 2-1 presents a side view of the capture and control system on the
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CHROME EXHAUST SYSTEM
(•LATINO
Figure 2-1. Side view of capture and control system at Precision Machine
and Hydraulic, Inc., Worthlngton, West Virginia.
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plating tank. The design airflow rate of the ventilation system is
140 cubic meters per minute (m3/min) (5,100 cubic feet per minute
[ft3/min]). The actual measured flow rate is 125 m3/min
(4,430 ft3/min).
The mesh-pad mist eliminator was fabricated and Installed in
May 1988 by ChromeTech, Inc., Bedford, Ohio. Figure 2-2 presents a
detailed schematic of the mesh-pad mist eliminator. The unit has a
design pressure drop of 0.62 kilopascal (kPa) (2.5 inches of water column
[in w.c.]) at a velocity of 150 to 210 meters per minute (500 to 700 feet
per minute).
Based on the static presure measured at the inlet and outlet of the mist
eliminator, the pressure drop recorded during testing was 0.62 kPa
(2.5 in. w.c.). The mist eliminator consists of two mesh pads spaced
approximately 10 cm (4 in.) apart. Each mesh pad is 79 cm (31 in.) in
diameter. The primary mesh pad at the inlet of the unit 1s 6.4 to 7.6 cm
(2.5 to 3.0 1n.) thick, and the secondary mesh pad at the outlet is 3.2
to 3.8 cm (1.25 to 1.5 in.) thick. Each mesh pad consists of layers of
interlocked polypropylene threads. Each thread is 0.05 cm (0.0200 in.)
in diameter. The thread count 1s 4.3 by 3.3 per square centimeter (28 by
21 per square Inch) and the weave type is honeycomb.
The unit 1s equipped with two spray nozzles which are activated
periodically to wash down the pads. One spray nozzle is located at the
inlet of the unit prior to the primary mesh pad and the other spray
nozzle is located at the outlet of the unit behind the secondary mesh
pad. The first nozzle sprays into the primary mesh pad in the direction
of airflow, and the second spray nozzle sprays into the secondary mesh
pad counter to the airflow. The ventilation system is shut off and the
spray nozzles are activated at the end of each day to wash down the mesh
pads. During each washdown, the mesh pads are flooded with 38 I
(10 gal) of water at a pressure of 1.7 to 2.0 atmospheres (25 to 30
pounds per square inch). The washdown water drains from the bottom of
the mesh-pad unit through a pipe directly to the plating tank. In
addition, the unit has a removable cover that allows the mesh pads to be
5
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CHROMETECII MODEL 18HME20-DX
HORIZONTAL MIST ELIMIXATOR
•Xv — VSVEH PCLYPRC V£SHPAD
3C
CUTOUT IN CASING r:R PAD REMOVAL —
PVC CASING
,_ PRIMARY ME2HPAD
SECONDARY MCSHPAD
^EHO'.'ABLE CCVER
1* DRAIN (T3 PLATING TANK)
4C aio.
VATER SPRAY
TOR M£SHPAD --
• - 50.5
Figure 2-2. Cross-sectional view of mesh-pad mist eliminator at Precision Machine
and Hydraulic, Inc., WortMngton, West Virginia.
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removed and cleaned by Immersion in the rinse tank. Immersion cleaning
is performed once a month.
2.3 PROCESS CONDITIONS DURING TESTING
Mass emission tests were conducted simultaneously at the inlet and
outlet of the mist eliminator unit to characterize the performance of the
control device in controlling chromic acid mist.
Process parameters recorded during each test run were plating
solution temperature, operating voltage, and operating current. In
addition, the number and surface area of parts plated during each test
run was recorded. Process data sheets documenting the process parameters
monitored during testing are presented in Appendix A. Average values for
the operating parameters recorded for each test run are presented in
Table 2-1. The process was operating normally during testing. The total
current supplied to the tanks during each test run was calculated in
terms of ampere-hours. A summary of the total current values is
presented in Table 2-2.
Grab samples of the plating solution were taken during each test
run to determine the Cr+6 concentration of the solution during
emission testing. The Cr+6 concentrations of the grab samples are
reported in Section 3 of this report.
The mesh pads were cleaned by immersion in the rinse tank prior to
the first test run. The mist eliminator washdown system was activated at
the end of test runs No. 1 and 5. The mesh pads were removed and cleaned
using a water hose at the end of test run No. 3. No grab samples of the
washdown water were obtained because the location of the drain pipe
outlet was 25 cm (10 in.) below the surface of the plating solution.
Test run No. 1 was 3 hours in duration, and the four subsequent
runs were each 2 hours in duration. Each test run was interrupted 20 to
30 minutes to change test ports.
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TABLE 2-1. AVERAGE OPERATING PARAMETERS DURING MASS EMISSION TESTS
Operating Operating Operating Surface area
Run Rectifier volatge, current, temperature, plated
No. No. volts amperes °C (°F) m2 (ft2)
1 1 4.6 2,800 56 (133) 1.4 (15.2)
2 5.4 3,700
2 1 4.7 2,000 56 (133) 1.3 (13.9)
2 4.9 3,000
3 1 4.7 1,500 56 (133) 1.3 (13.4)
2 4.9 3,700
4 1 4.7 1,200 55 (131) 1.1 (12.3)
2 5.0 3,600
5 1 4.9 1,300 56 (133) 1.1 (11.7)
2 4.7 3,600
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TABLE 2-2. TOTAL CURRENT SUPPLIED TO PLATING TANK DURING
MASS EMISSION TESTS
Run
No.
1
Total a
2
Total a
3
Total a
4
Total a
5
Total a
Rectifier No.
1
2
1
2
1
2
1
2
1
2
Total current
ampere-hours
Inlet
9,236
11.833
21,100
3,899
6.101
10,000
3,003
7.403
10,400
2,489
7.130
9,600
2,601
7.093
9,700
Outlet
9,236
11.833
21,100
3,899
6.101
10,000
3,003
7.403
10,400
2,489
7.130
9,600
2,601
7.093
9,700
aTotals are rounded to nearest 100.
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SECTION 3.0
SUMMARY OF RESULTS
INTRODUCTION
Five Modified Method 13B (MM13B) samples were collected at each
sample location. All of the emission samples were analyzed on site for
Cr+6 concentrations using the procedures outlined in the method
entitled "Draft Method-Determination of Hexavalent Chromium in Dry
Particulate Emissions from Stationary Sources". This analytical method
is presented in Appendix D.
In addition to the emission samples, grab samples of the plating
bath were composited during each MM13B run and analyzed using the same
colorlmetric procedures used for the emission samples. Table 3-1
presents a schedule of the activities during the test program. The
results from the sampling program are presented in the remainder of this
section.
HEXAVALENT CHROMIUM EMISSION RESULTS
Emission samples were collected isokinetically using a Method 13B
sample train that had been modified by removing the glass fiber filter
and placing 100 mft- of 0.1N NaOH in each of the first two impingers.
The impinger solutions were recovered into tared polyethylene sample
bottles and the total volume of the recovered samples was determined
gravimetrlcally. Following recovery of the samples, an aliquot of the
solution was analyzed for Cr+6. The following subsections present
the flue gas data and analytical results for each sample location.
10
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TABLE 3-1. SCHEDULE OF ACTIVITIES
Date
(1988)
9/20
9/20
9/20
9/20
9/21
9/21
9/21
9/21
9/21
9/21
9/21
9/21
9/22
9/22
9/22
9/22
9/22
9/22
9/22
9/22
Sample
Tvpe
MM13B
SM
SM
plating sol .
MM13B
SM
SM
plating sol .
MM13B
SM'
SM
plating sol .
MM13B
SM
SM
plating sol.
MM13B
SM
SM
plating sol .
Test Time
Run No. (Minutes)
1-1, 0-1 192
01 series
11 series
1
1-2, 0-2 120
12 series
02 series
2
1-3, 0-3 120
13 series
03 series
3
1-4, 0-4 120
14 series
04 series
4
1-5, 0-5 120
15 series
05 series
5
Parameter
Measured
Cr+6
Cr+6
Cr+6
Cr+6
Cr+s
Cr+6
Cr+6
Cr*6
Cr+6
Cr+6
Cr+6
Cr+fi
Cr+6
Cr+6
Cr+s
Cr+6
Cr+6
Cr+6
Cr+6
Cr+6
11
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Inlet to the Mesh-Pad Mist Eliminator
Modified Method 13B--
A summary of the flue gas conditions at this location are presented
1n Table 3-2. The volumetric flowrates were consistent and averaged
121 dry standard cubic meters per minute (dscmm), (4,273 dry standard
cubic feet per minute, (dscfm)). The flue gas temperature averaged 24°C
(76°F) and the moisture content averaged 1.64 percent. The flue gas was
essentially ambient air and was assigned a dry molecular weight of
28.95 Ib/lb mole. The isokinetic sampling rates were within the
allowable limitations for these sample runs.
Prior to sampling, 1t was decided that the first MM13B run should
be run at 8 minutes per point for a total sample time of 192 minutes.
This sample time ensured the collection of a detectable concentration of
Cr+6. Following the analysis of the sample, 1t was determined that
the sample time per point could be reduced to 5 minutes, for a total
sample time of 120 minutes. The uncontrolled emissions as measured In
each MM13B run were consistent and averaged 11.4 mg/dscm (0.005
gr/dscf). A summary of the MM13B sample volumes, analytical results and
emission rates for this location 1s presented 1n Table 3-3.
Outlet from the Mist Eliminator
Modified Method 13B—
A summary of the flue gas conditions at this location are also
presented 1n Table 3-2. The volumetric flowrates were consistent and
averaged 118 dry standard cubic meters per minute (dscmm), (4,173 dry
standard cubic feet per minute, (dscfm)). The flue gas temperature
averaged 26°C (79°F) and the moisture content averaged 1.71 percent. The
flue gas was essentially ambient air and was assigned a dry molecular
weight of 28.95 Ib/lb mole. The isokinetic sampling rates were within
the allowable limitations for these sample runs.
12
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TABLE 3-2. SUMMARY OF FLUE GAS CONDITIONS
Run No.
1-1
0-1
1-2
0-2
1-3
0-3
1-4
0-4
1-5
0-5
Date
9/20/88
9/20/88
9/21/88
9/21/88
9/21/88
9/21/88
9/22/88
9/22/88
9/22/88
9/22/88
Volumetric Flowrate
dscm/min dscf/min
118 4,157
117
125
118
119
118
123
120
120
118
4,144
4,429
4.177
4,194
4,152
4,343
4,224
4,235
4,167
Temperature
°C °F
27
29
22
24
24
26
22
23
27
28
82
85
72
75
75
78
71
74
80
83
X Moisture
1.54
1.59
1.59
1.67
1.24
1.70
1.69
1.75
1.92
1.85
X Isokinetic
98.5
97.6
98.9
99.6
99.2
99.8
99.9
100.1
100.1
100.6
13
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TABLE 3-3. SUMMARY OF SAMPLE VOLUMES, ANALYTICAL RESULTS AND
EMISSION RATES FOR THE MESH-PAD MIST ELIMINATOR INLET
Run No.
1-1
1-2
1-3
1-4
1-5
Stack
dscfm
4157
4429
4194
4393
4235
Vol ume
Metered
dscf
165.672
110
105
109
107
.820
.286
.801
.227
Total Mass
Cr+6. mq
34
32
35
43
40
.012
.794
.798
.325
.564
Concentration
mg/dscm gr/dscf
7.2499 0.00317
10
12
13
13
.4502
.0070
.9341
.3593
0
0
0
0
.00457
.00525
.00609
.00584
Emission
ka/hr
0.0512
0.0786
0.0856
0.1028
0.0961
Rates
Ib/hr
0.113
0.173
0.189
0.227
0.212
14
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As was done for the Inlet testing, 1t was decided that the first
MM13B run should be conducted at 8 minutes per point for a total sample
time of 192 minutes. This increased sample time ensured the collection
of a detectable concentration of Cr+6. Following the analysis of the
sample, 1t was determined that the sample time per point could be reduced
to 5 minutes for a total sample time of 120 minutes. The controlled
emissions measured in each MM13B were consistent and averaged 0.03
mg/dscm (0.00001 gr/dscf). A summary of the MM13B sample volumes,
analytical results and emission rates for this location are presented in
Table 3-4.
The Cr*6 removal efficiencies for the system were consistent and
averaged 99.7%. A summary of removal efficiencies for the system is
presented 1n Table 3-5.
PLATING TANK SOLUTIONS
During each MM13B run, grab samples of the plating bath solution were
collected and composited. The samples were analyzed for Cr+6
concentration. The results from these analyses are presented in
Table 3-6.
SCREENING METHOD RESULTS
Screening method samples were taken at the Inlet and outlet of the
control device at the same time the Modified Method 13-B samples were
taken. The screening method apparatus was the same as used at Roll
Technology in August 1988. A piece of 1/8" I.D. Teflon tubing (24 inches
long) followed by a 37 mm Millipore filter comprised the part of the
train where the sample was collected. Approximately 10' of Tygon tubing
connected the tubing-filter assembly to another Millipore filter followed
by a hypodermic needle that was connected to a leakless vane pump by
another short piece of Tygon tubing. This system was arranged in
quadruplicate. This "Quad" probe assembly traversed the stack during the
15
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TABLE 3-4. SUMMARY OF SAMPLE VOLUMES, ANALYTICAL RESULTS AND
EMISSION RATES FOR THE MESH-PAD MIST ELIMINATOR OUTLET
Run No.
0-1
0-2
0-3
0-4
0-5
Stack
dscfm
4144
4177
4152
4224
4167
Vol urne
Metered
dscf
174.537
112
111
114
113
.193
.821
.023
.046
Total Mass
Cr+6. mg
0
0
0
0
0
.2911
.1018
.1077
.0891
.0338
Concentration
tng/dscm qr/dscf
0.0589 0.00003
0
0
0
0
.0320
.0340
.0276
.0106
0.00001
0.00001
0.00001
0.000005
Emission
ka/hr
0
0
0
0
0
.0004
.0002
.0002
.0002
.0001
Rates
Ib/hr
0.0009
0.0005
0.0005
0.0004
0.0002
16
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TABLE 3-5. SUMMARY OF Cr+6 REMOVAL EFFICIENCIES
Run No.
1-1
0-1
1-2
0-2
1-3
0-3
1-4
0-4
1-5
0-5
Average
Run No.
1-1
0-1
1-2
0-2
1-3
0-3
1-4
0-4
1-5
0-5
Average
Cr+6 Emission Rate Ib/hr
0.113
0.0009
0.173
0.0005
0.189
0.0005
0.227
0.0004
0.212
0.0002
Cr+6 Concentration (mq/m3)
7.2499
.0589
10.4502
.0320
12.0070
.0340
13.9508
.0276
13.3593
.0106
Cr+6 Removal Efficiency
99.2%
99.7%
99. 7X
99.8%
99.9%
99.7%
Cr+6 Removal Efficiency
99.2%
99.7%
99.7%
99.8%
99.9%
99.7%
17
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TABLE 3-6. SUMMARY OF PLATING SOLUTION
ANALYTICAL RESULTS
Run No. Cr+6 Concentration,
Plating Solution
1-1 97,128
1-2 101,724
1-3 102,279
1-4 104,818
1-5 102,001
18
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regular test effort. Due to the size of the "Quad" probe assembly, 1t
was not possible to sample all the points that the MM-13B trains
sampled. Nine out of 12 points were sampled on each traverse. Total
screening sample time was the same as the Modified Method 13B trains.
As has happened 1n the past, the outlet measurements were more
reproducible than the Inlet measurements. Inlet locations have usually
been close to the plating tank and chromic add globules may break loose
from the duct walls and bias some of the samples high. Reproducility is
much better at the outlet.
During this screening effort, 1t became apparent that if sampling
is done at a constant rate for uniform time intervals, traversing the
stack will always bias the results low, because the procedure does not
correct sample volumes to account for velocity differences. Thus samples
collected at low flow points will be sampled for too long while samples
at high flow points will be too short.
Another problem that has become evident in the screening method is
the determination of the volume of sample collected. A hypodermic needle
in ambient air will give reproducible volumes. This principle is applied
when hypodermic needles are used to check meter box specifications in the
field. Whenever something (such as Tygon tubing) 1s placed in front of
the needle, the volume changes. Furthermore, the ideal gas low cannot be
used to determine volumes at other temperatures and pressures based on a
set of conditions and data obtained in the lab. Nhile it would be
possible to develop the equations needed to theoretically determine
sample volumes at a test site, this would be costly, time consuming , and
complicated to use.
Clearly, a simple method of determining volumes is needed. Two
techniques have been experimented with, and both use the empirical
approach. The first method involves filling a container with water,
19
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weighing it, and then submerging the container into a larger container of
water. The sampling train is turned on; an outlet hose on the pump is
placed into the smaller container; and the time for the displacement is
recorded. The container is then weighed again and the loss of weight is
the weight of water displaced. Using these data, a sample volume can be
calculated.
The above method has some drawbacks. First, a scale that will
weigh up to 8 pounds in accurate increments is necessary. Such scales
are expensive. In addition, two people are required to insert the tube
and operate the stopwatch. The outside of the container, when weighed,
must always be dry.
The second method to determine volume also involves water
displacement, but in this case the container is weighted. Using a
weighted container, there is no need to hold the container under water
with one hand while holding the outlet hose from the pump with the
other. The person making the volume determination can insert the hose
with one hand while operating the stopwatch with the other. When the
container rises from the bottom of the larger container, the time is
recorded and the volume determined.
Both methods have been tried in the laboratory. The lack of a good
scale and the necessity of using two people for volume determinations
makes the first approach unattractive. The second method (weighted
container) has been tested in the lab and gives volumes within 2 percent
of the true volume (true volume determined with a spirometer).
For the next screening method test effort, the first Millipore
filter that follows the segment of Teflon tubing will be replaced with a
set of midget impingers. The first two impingers will contain 15 ml. of
0.1 Normal NaOH. The third will be empty and the fourth will contain
20
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silica gel. Sampling times per point will be adjusted for velocity
traverse data. Sampling runs will be approximately the same length of
time as the MM13B runs.
The results of the screening runs for the West Virginia Test are
presented 1n tables 3-7 and 3-8.
21
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TABLE 3-7. INLET SCREENING METHOD RESULTS
Screening
Run No.
I-l-A
I-l-B
I-1-C
I-l-D
I-2-A
I-2-B
I-2-C
I-2-D
I-3-A
I-3-B
I-3-C
I-3-D
I-4-A
I-3-B
I-4-C
I-4-D
I-5-A
I-5-B
I-5-C
1-5-0
Volume
Samoles
28.2660
26.7795
27.9414
23.9651
(Sample
16.9238
16.0337
16.7294
14.3486
17.157
16.2547
16.9600
14.5464
16.8368
15.9514
16.6435
14.2750
17.4167
16.5008
17.2167
14.7666
Stack
DSCFM
4157
4157
4157
4157
I-l-D
4429
4429
4429
4429
4194
4194
4194
4194
4343
4343
4343
4343
4235
4235
4235
4235
Screen
ma/M3
14.923
9.166
3.320
45.322
spilled during
7.2953
4.9549
6.3637
9.3789
12.5391
11.8034
3.0442
4.5228
11.1961
11.4168
10.9081
11.9288
12.2588
11.2357
4.3587
13.2344
MM13B
Mq/M3
7.2535
7.2535
7.2535
7.2535
recovery)
10.4498
10.4498
10.4498
10.4498
12.0070
12.0070
12.0070
12.0070
13.9341
13.9341
13.9341
13.9341
13.3593
13.3593
13.3593
13.3593
X Of
MM13B
205.74
126.37
45.77
624.83
69.81
47.42
60.90
89.75
104.43
98.30
25.35
37.67
80.35
81.93
78.28
85.61
91.76
84.10
32.63
99.07
22
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TABLE 3-8. OUTLET SCREENING METHOD RESULTS
Screening
Run No.
0-1-E
0-1 -F
0-1 -G
0-1 -H
0-2-E
0-2-F
0-2-G
0-2-H
0-3-E
0-3-F
0-3-G
0-3-H
0-4- E
0-4-F
0-4-G
0-4-H
0-5-E
0-5-F
0-5-G
0-5-H
Vol ume
Samples
31.9449
45.7199
45.4538
47.0541
19.1329
27.3833
27.2239
28.1823
19.3226
27.6547
27.4937
28.4617
19.0395
24.2496
27.0910
28.0448
19.7133
28.2140
28.0497
29.0373
Stack
DSCFM
4144
4144
4144
4244
4177
4177
4177
4177
4152
4152
4152
4152
4224
4224
4224
4224
4167
4167
4167
4167
Screen
ma/M3
.0358
.0244
.0253
.0362
.0161
.0133
.0071
.0069
.0046
.0195
.0197
.0200
.0169
.0106
.0123
.0137
.0084
.0081
.0087
.0084
MM13B
Ma/M3
.0597
.0597
.0597
.0597
.0320
.0320
.0320
.0320
.0340
.0340
.0340
.0340
.0254
.0254
.0254
.0254
.0106
.0106
.0106
.0106
% of
MM13B
59.97
40.87
42.38
60.64
50.31
41.56
22.19
21.56
13.53
57.35
57.94
58.82
66.53
41.73
48.43
53.94
79.25
76.42
82.08
79.25
23
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SECTION 4.0
SAMPLING LOCATIONS AND TEST METHODS
EMISSION SAMPLES
Location of Measurement Sites
EPA Reference Method 1 "Sample and Velocity Traverse for Stationary
Sources" was used to select representative measurement sites. The
diameter of the duct at the Inlet measured 17.6 Inches. Two sample ports
were cut 1n the duct at 90 degrees from each other. The straight run of
duct was 1 foot In length. Therefore, the measurement site did not meet
minimum sampling criteria.
The measurement site for the outlet of the mist eliminator was
located in a 19.5 Inch diameter vertical duct. This measurement site met
minimum sampling requirements.
According to EPA Method 1 criteria, each site required 24 sample
traverse points, 12 on each diameter. Table 4-1 shows the traverse
points used.
Prior to sampling, verification of the absence of cyclonic flow at
each sample traverse point was assessed based on procedures described in
EPA Reference Method 1. In this method the face openings of the Type-S
pitot tube are aligned perpendicular to the duct cross-sectional plane,
designated "0-degree reference." Null (zero) pitot readings obtained at
0-degree reference indicate an acceptable flow condition at a given
point. If the point reading was not zero at 0-degree reference, the
pitot was rotated until a null reading was obtained. The value of the
24
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TABLE 4-1. SAMPLE TRAVERSE POINT LOCATIONS FOR THE MESH-PAD MIST
ELIMINATOR INLET AND OUTLET
Traverse
Point
No.
Location (Inches)
M1st Eliminator
Inlet
Mist Eliminator
Outlet
1
2
3
4
5
6
7
8
9
10
11
12
0.5
1.2
2.1
3.1
4.4
6.3
11.4
13.2
14.5
15.5
16.4
17.1
0.5
1.3
2.3
3.5
4.9
6.9
12.5
14.6
16.0
17.2
18.2
19.00
25
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rotation angle (yaw) was recorded for each point and averaged across the.
duct. Method 1 criteria stipulate that average angular rotations greater
than 20 degrees Indicate cyclonic (nonaxlal) flow conditions 1n the
duct. Both of these sites Indicated acceptable flow patterns so that
extraction of representative samples from these sites was performed using
appropriate sampling procedures.
Test Methods
Velocity and static pressures, moisture content, and temperature
were measured prior to sampling, 1n order to define sampling rates and
nozzle sizes as described In the EPA Reference Methods 1, 2 and 4.
An EPA MM13B sample train was used to collect the Cr+6
samples. The sample train consisted of a 316 stainless steel button-hook
nozzle, an unheated Pyrex glass-lined probe, and a series of four
1mp1ngers. The first, third and fourth Impingers were Greenburg-Smith
design, modified by replacing the tip with a l/2-1n. Inside diameter
glass tube extending to l/2-1n. from the bottom of the flask. The second
1mp1nger was a Greenburg-Smith 1mp1nger with the standard tip. The first
and second Impingers contained lOOmft. of 0.1N NaOH. The third Impinger
was empty and the fourth Impinger contained approximately 200 grams of
silica gel. The balance of the sampling system consisted of a vacuum
pump, dry gas meter, calibrated orifice and related temperature and
pressure Indicating apparatus to determine dry gas sample volume, stack
gas temperature, volumetric flow rate and Isokinetic sampling rates.
During sampling, stack gas temperature and the gas temperature exiting
the last Impinger were monitored with calibrated thermocouples.
The sampling time was decreased from 8 minutes per point (192
minute total sample time) to 5 minutes per point (120 minute total sample
time) since the concentration of Cr+6 was such that good analytical
results could be obtained using the shorter time.
26
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The 1mp1ngers were weighed before and after each test to determine
the moisture content of the flue gas stream. All connecting glassware,
the nozzle and probe were rinsed with 0.1N NaOH and combined with the
impinger solution Into a tared polyethylene sample bottle. The total
volume of the sample was determined gravimetrically. The liquid level
was marked on each sample bottle and each bottle was marked indicating
the run number and bottle contents.
Following the recovery of the samples, all samples, including
blanks, were analyzed for Cr+6 concentration using the analytical
methodology developed by the EPA.
EMISSION SAMPLE ANALYSIS
The MM13B samples and the plating solution were analyzed for
Cr+6 concentration. The analyses were conducted on site in the EPA
mobile laboratory. Immediately following the sample recovery, the
samples were submitted to the analyst and the analyses and calculations
were performed the same day. The analytical results were calculated on
the Hewlett Packard 41CV computer that was set up 1n the on-s1te computer
center. The calculations were also performed by the EPA Task Manager.
The analytical method entitled "Draft Method - Determination of
Hexavalent Chromium in Dry Partlculate Emissions from Stationary Sources"
was used as a "guideline" in conducting the analyses. This method is
currently under development by the EPA and 1s presented in Appendix D.
There were several variations between the draft method and the
analytical method that was performed in the field. They are described as
follows:
1. The collected samples were not digested in an alkaline
solution. Aliquots of the recovered samples were pipeted
directly from the sample bottle and prepared as in paragraph
5.7.1 of the Draft Method.
27
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2. The pH of the sample aliquot was monitored with a pH meter while
adjusting the pH of the aliquot to 2 ± .5.
3. The spectrophotometer was calibrated with standards containing
2 mfi,, 5 ma, 7 ma, 10 ml, 15 mfi, and 20 mil of the
5 jig/mil working standard. The spectrophotometer calibration
factor, KC, was calculated as follows:
A + 2.5A + 3.5A, + 5A, + 7.5A. + 10A,
X 2 34 56
KC - 10
4. The value of this calibration factor was calculated using a computer
program that was developed by the EPA Task Manager for the HP41
calculator.
28
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SECTION 5.0
QUALITY ASSURANCE
INTRODUCTION
The goal of the quality assurance activities for this project is to
ensure, to the highest degree possible, the accuracy of data collected.
The procedures contained 1n the "Quality Assurance Handbook for Air
Pollution Measurement Systems," Volume III, "Stationary Source Specific
Methods," EPA-600/4-77-027B served as the basis for performance of all
testing and related work activities that were undertaken in this testing
program. In addition to the quality assurance measure guidelines
presented above, specific quality assurance activities were conducted for
several of the individual testing activities, as performed; these are
presented in the paragraphs that follow.
FIELD QUALITY ASSURANCE PROCEDURES
In order to assure a high level of quality control while sampling
to allow the comparison of data from these two methods, a field quality
assurance program was followed during the test program. Methods used to
obtain the required level of quality assurance are itemized below.
Sample Blanks
Reagent Blanks—
The 0.1N NaOH absorbing solution was transported to the field in
its "as-purchased" container. When in the field, the 0.1N NaOH was
transferred to a polyethylene wash bottle. From the wash bottle, the
NaOH solution was used for sample train preparation and recovery.
29
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A blank sample was collected from the solution in the wash bottle. This
sample was given to the on-site laboratory personnel with the emission
samples, and analyzed In the same manner. Results of the blank analyses
are presented 1n Table 5-1.
HaO Blanks—
A distilled water blank was obtained from the wash bottles and
analyzed 1n the same manner as the emission samples.
Duplicate Samples
One sample for every 10 samples analyzed was a duplicate, e.g., 1f
24 samples were analyzed, 3 duplicate samples would be analyzed. The
analytical results for the duplicated samples are presented In Table 5-1.
Standards
Dally, throughout the analysis of the samples, standards were set
up as a spot check of the spectrophotometer calibration. The results of
these checks are presented in Table 5-1.
Chain of Custody
In an effort to maintain the Integrity of all samples taken at the
test facility, a chain of custody procedure was followed. Once the
samples were placed In custody of the analytical group, that group
provided for safe storage and maintenance of records sufficient to
maintain sample Integrity. The "Chain of Custody" data sheets are
presented in Appendix E.
Sample Transfer
All MM13B samples collected during testing remained in the custody
of EPA personnel and were secured in the mobile laboratory while in the
field.
30
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TABLE 5-1. SUMMARY OF ANALYTICAL RESULTS FOR QA/QC SAMPLES AND BLANKS
Samole No.
0-1
50 yg/100 ma
75 pg/100 ml
O-A-2
0-3
10 jig/100 ma
I-3-B
10 yg/100 ma
75 yg/100 ma
50 }ig/100 ma
Plating Sol .
Run 2
Blanks
0.1N NaOH
0.1N NaOH
0.1N NaOH
H20
Date (1988)
9/20
9/20
9/21
9/21
9/22
9/22
9/22
9/22
9/22
9/29
9/29
9/20
9/21
9/22
9/29
Tvpe of Sample
Duolicate Standard Total pa Cr+6
X 288
X 53.0
X 76.8
X 101.8
X 110.6
X 9.9
X 5,484
X 10.2
X 73.2
X 51.84
X 101,172 jig/ma
0.44
0.00
0.00
0.00
31
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SAMPLING TRAIN COMPONENTS
The equipment used 1n this test program, Including nozzles, pi tot
tubes, dry gas meters, orifices, and thermocouples were uniquely Identified
and were calibrated 1n accordance with calibration procedures specified In
the applicable EPA Reference Method prior to, and at the completion of the
testing program. The calibration sheets are presented 1n Appendix F.
VERIFICATION OF CALCULATIONS
Emission Calculations
Dry gas volumes, percent moisture of the stack gas, gas flow rates,
and Cr*6 emission rates were calculated using a Hewlett Packard 41CV
programmable calculator. The programs used can be found 1n the document:
"Source Test Calculation and Check Programs for Hewlett Packard 41
Calculators" (EPA-340/1-85-018). The results were checked and verified by
the contractor task manager.
Chromium Concentration Calculations
All absorbance data for blanks, standards, samples and QA/QC samples
were documented In a notebook. The Cr+6 content and total mass of
Cr+6 collected were calculated using a program developed by the EPA Task
Manager for the HP41CV programmable calculator.
32
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