EPA
United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
RTF, NC 27711
EMB Report 89-CEP-l 5
FEBRUARY 1989
Air
CHROMIUM
ELECTROPLATERS
TEST REPORT
HARD CHROME
SPECIALISTS, INC.
YORK
PENNSYLVANIA
SUMMARY REPORT
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EPA Contract No. 68-02-4346
Work Assignment 4
August 22, 1989
Determination of the Efficiency of a
Mesh-Pad Mist Eliminator
Candidate Plant
Hard Chrome Specialists, Inc.
York, Pennsylvania
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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CONTENTS
Section Page
1.0 Introduction 1
2.0 Process Operation 4
3.0 Summary of Results 14
4.0 Sampling Locations and Test Methods 24
5.0 Quality Assurance 29
FIGURES
*
Figures Page
1-1 Location of sample points 2
2-1 Hard Chrome Specialists, Inc., plant layout 5
2-2 Mesh-pad mist eliminator schematic 7
2-3 Air pollution control system 8
TABLES
Table Page
2-1 Average Operating Parameters During Each
Mass Emission Test Run 10
2-2 Total Current Supplied to Plating Tank
During Each Mass Emission Test Run 12
3-1 Schedule of Activities 15
3-2 Summary of Flue Gas Conditions 17
3-3 Summary of Sample Volumes, Analytical Results
and Emission Rates for the Mesh-Pad Mist
Eliminator Inlet 18
in
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CONTENTS (continued)
Table Page
3-4 Summary of Sample Volumes, Analytical Results and
Emission Rates for the Mesh-Pad Mist
Eliminator Outlet 20
3-5 Summary of Cr+6 Removal Efficiencies 21
3-6 Summary of Plating Solution Analytical Results 22
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
APPENDICES
A Field Data Sheets A-l
B Draft Method for Chromium Analysis B-l
C Chain of Custody C-l
D Equipment Calibration Data D-l
E Process Data .' E-l
F Project Participants and Activity Log F-l
IV
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SECTION 1.0
INTRODUCTION
During the week of January 30, 1989, an emission measurement program
was conducted at Hard Chrome Specialists, Inc. in York, Pennsylvania.
The purpose of this program was to collect data to determine the
efficiency of a mesh-pad mist eliminator, and also to determine the
effectiveness of polypropylene balls in controlling emissions from the
surface of the plating bath. The data gathered will be used as a second
data set to confirm the performance of an identical mesh-pad mist
eliminator which was found to have achieved 99.7% control of hexavalent
chromium (Cr+6) emissions.
The principal reason for selecting Hard Chrome Specialists, Inc. 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 emissions were measured at two locations along the
duct. These locations are identified in Figure 1-1 as: 1) inlet sample
site and 2) outlet sample site.
The emission samples were collected using a Modified Method 13B
(MM13B) sample train. This method will be discussed in Section 4.0.
The samples were analyzed for Cr+6 concentration using the
diphenylcarbazide colorimetric method. This method will also be
discussed in Section 4.0.
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(2) Outlet Sample Site
Mesh-pad mist eliminator
46'
36.8'
11.3 FEET
rt
Grab Sample
Location ^
Plating
Tank
l\
Fan
(1) Inlet
Sample
Site
9.8 FEET
Wall
Floor
Fume Hood
Figure 1-1. Diagram of sample sites.
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PEER Consultants, P.C., located In Dayton, Ohio was responsible for
developing the test protocol, conducting the field test, performing
on-site analysis of samples and the preparation of draft and final
reports. PEER was supported by its subcontractor, Pacific Environmental
Services, Inc. located in Cincinnati, Ohio. Midwest Research Institute,
located in Raleigh, North Carolina, was responsible for monitoring the
process operation, and EPA personnel conducted Screening Method testing
and monitored the implementation of the test protocol.
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SECTION 2.0
PROCESS OPERATION
2.1 PROCESS DESCRIPTION
Hard Chrome Specialists, Inc., is a job shop that plates industrial
rolls, hydraulic components, dies, and molds. The hard chromium plating
line at this facility consists of an alkaline strip tank to clean the
parts prior to plating, two alkaline rinse tanks, an alkaline scrub tank,
and the hard chromium plating tank followed by a spray rinse tank and by
three countercurrent rinse tanks. A floor plan of the facility is
presented in Figure 2-1.
The hard chromium plating tank is 1.8 m (6.0 ft) long, 0.76 m
(2.5 ft) wide, and 4.3 m (14.0 ft) deep and holds approximately 5,720
liters (fi.) (1,510 gallons [gal]) of plating solution. The plating tank
usually operates 8 hours per day, 5 days per week. Typical plating times
for each part range from 0.5 to 20 hours. For parts that require a
plating time in excess of 8 hours, the parts are plated over the course
of 2 days. The plating solution contains chromic acid in a concentration
of about 210 grams per liter (g/a) (28 ounces per gallon [oz/gal]) of
water. Sulfuric acid is used as a catalyst at a bath concentration of
2.1 g/H (0.28 oz/gal). The temperature of the plating solution is
maintained between 54° and 60°C (130° and 140°F). The plating tank is
equipped with an air agitation system to maintain uniform bath
temperature and chromic acid concentration. The maximum current and
voltage of the rectifier is 8,000 amperes and 9 volts.
2.2 AIR POLLUTION CONTROL
The capture and control on the plating tank consist of a
single-sided lateral hood ducted to a mesh-pad mist eliminator.
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10-ton Evaporative
Cooling Tower
3000 Amp x 9 Volt
8000 Amp x 9 Volt
SCR Rectifier
SCR
Rectlller
1 1
EQUIPMENT ROOM
^
Horizontal
Chemical Mist
Eliminator
Scrub Reservoir
if
\
30'x30'x
1 V
*
1
168'
\\
—1
— "
G
, .
^
_i i in in ii ii i
7 Fixture Storage
Masking
W
f
^
Table
1 II 1 HI II II 1
Fixture Storage
Strip Tank Alkaline
30'x36'x168' Rlnae Tanka
ao'xeo-xies"
Plat.no Tank
Spray
ae Tan
30'x30'x188'
Counlerllow
R|nae TflnkB
30'x90-xie8"
Site for Future
Plating Tank
Figure 2-1. Hard Chromium Specialists, Inc., plant layout.
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Figure 2-2 presents a schematic of the capture and control system on the
hard chromium plating tank.
The mesh-pad mist eliminator was fabricated and installed in
November 1988 by ChromeTech, Inc., Bedford, Ohio. Figure 2-3 presents a
detailed schematic of the mesh-pad mist eliminator. The design airflow
rate of the ventilation system is 110 dry standard cubic meters per
minute (m3/min) (3,800 dry standard cubic feet per minute
[ft3/min]. The mesh-pad mist eliminator unit has a pressure drop of
0.62 kilopsacal (kPa) (2.5 inches in water column [in. w.c.]) at a gas
velocity of 150 to 210 meters per minute (500 to 700 feet per minute).
The mist eliminator consists of two mesh pads spaced approximately
10 centimeters (cm) [4 in.] apart. Each mesh pad is 79 cm (31 in.) in
diameter. The primary mesh pad at the inlet of the unit is 6.4 to 7.6 cm
(2.5 to 3.0 in.) thick, and the secondary mesh pad is 3.2 to 3.8 cm (1.25
to 1.5 in.) thick. Each mesh pad consists of interlocked polypropylene
filaments. Each thread is 0.051 cm (0.0200 in.) in diameter. The thread
count is 4.3 by 3.3 per square centimeter (28 by 21 per square inch) and
the weave type is honeycomb.
Removal of chromic acid mist is accomplished by direct interception
of impaction of the chromic acid mist on the mesh pads. The collected
droplets then coalesce along the fibers and drain down the pads into the
drain pipe located at the bottom of the unit.
The mist eliminator unit is equipped with two spray nozzles to
clean the pads. One spray nozzle is located at the inlet of the unit
prior to the first mesh pad, and the other spray nozzle is located behind
the second mesh pad. The first nozzle sprays intothe first mesh pad in
the direction of the airflow, and the second nozzle sprays into the
second mesh pad countercurrent to the airflow. The first spray nozzle
uses rinse water from the first rinse tank following the plating tank,
and the second spray nozzle uses clean tap water. At the end of each
day, the ventilation system is shut off and the spray nozzles are
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STACK
FAN
MESH-PAD
MIST ELIMINATOR
PLATING
TANK
Figure 2-2. Air pollution control system.
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oo
HORIZONTAL MIST ELItflKATOR
PDLVPRQ MESHPAD
PRIMARY MF^HP Atl
cimwT IM CAsi.ir, FOR PAD REHOVAL -n / ^VCONDMN HESHPAD
PVC CASING
VATER SPRAT
TOR HESMPAD
REHDVABl-E CDVER
I' DRAUI (TU I'LAIING TANK)
Figure 2-3. Mesh-pad nlst eliminator schematic.
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activated for approximately 30 seconds to wash down the mesh pads.
Typically, 23 to 39 liters (6 to 10 gallons) of water are used each time
the pads are cleaned. The washdown is drained to the plating tank. In
addition, the unit is designed so that the mesh pads can be easily
removed and cleaned by immersion in the plating bath. The immersion
cleaning is performed once a month.
2.3 PROCESS CONDITIONS DURING TESTING
Five mass emission test runs were conducted at the inlet and outlet
of the mesh-pad mist eliminator. During this source test program, the
plating tank was operated with and without polypropylene balls covering
the surface of the plating solution. The first three test runs were
conducted on the system without any polypropylene balls on the plating
tank surface to determine the effectiveness of the mesh-pad mist
eliminator. The two subsequent test runs were conducted while
polypropylene balls covered the surface of the plating solution to
determine their effectiveness in controlling chromic acid mist at the
surface of the plating solution. During test runs No. 4 and 5,
polypropylene balls covered the entire surface of the plating solution.
The ball coverage was two to three layers thick in most places. Each
polypropylene ball was 3.8 cm (1.5 in.) in diameter. There was no
observed dispersion of polypropylene balls away from the cathode area
during plating due to the relatively thick coverage supplied by the
balls. In typical industrial applications, coverage is not usually as
complete as in the case tested.
Process parameters recorded during each test run were the operating
current, the operating voltage, and the plating solution temperature. In
addition, the pressure drop across the mesh-pad mist eliminator unit was
recorded. Process data sheets documenting the process and control device
parameters monitored during testing are presented in Appendix E. Data on
the average operating parameters recorded for each test run are presented
in Table 2-1. The plating tank was plating one or two hydraulic
9
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TABLE 2-1. AVERAGE OPERATING PARAMETERS DURING EACH MASS
EMISSION TEST RUN
Run No.
Operating Operating
current voltage,
amperes volts
Temperature
of plating
solution
°C (°F)
1
2
3
4
5
3,000
3,000
5,400
3,000
3,000
4.6
4.7
5.0
5.0
5.0
54 (130)
55 (131)
55 (131)
56 (132)
56 (132)
10
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cylinders during each test run. A single, 18-cm (7 in.) diameter roll,
175 cm (69 in.) long, was plated during Runs No. 1, 2, 4, and 5. This
cylinder and another hydraulic cylinder, with a diameter of 14 cm
(5.5 in.) and a length of 173 cm (68 in.), were plated during test run
No. 3. During plating, no visible misting was observed escaping the
plating tank's ventilation system. During test runs No. 4 and 5, visible
misting was observed above the polypropylene balls; however, the mist was
captured by the ventilation system. The total current supplied to the
tank during each test run was calculated in terms of ampere-hours and is
reported in Appendix E. A summary of the total current values is
presented in Table 2-2.
The fan speed was increased after test run No. 1, on the
recommendation of the control system vendor, ChemTech, Inc. The vendor
felt that increasing the air flow was necessary to operate closer to the
design condition. The inlet gas flow rate during testing ranged from 88
to 93 dry standard m3/min (3,100 to 3,300 dry standard ft3/min).
The outlet flow rates ranged from 99 to 108 dry standard m3/min
(3,500 to 3,800 dry standard fts/min). The outlet flow rate was 6 to
16 percent greater than the inlet flow rate. The larger outlet flow rate
resulted from an inadequate seal around the mesh pads which allowed
ambient air to be drawn into the system.
Grab samples from the plating tank were taken during each test run
to determine the Cr+6 concentration of the plating solution during
emission testing. The mist eliminator was washed down at the end of each
day, and grab samples of the washdown water were collected. The Or"1"6
concentrations of the grab samples are reported in Section 3 of this
report.
Test runs No. 1 and 4 were 3 hours in duration, and the remaining
test runs were 2 hours in duration. A slightly larger sampling nozzle
was used during test runs No. 4 and 5, which resulted in a larger sample
volume collected. The larger nozzle was used to ensure adequate sample
11
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TABLE 2-2. TOTAL CURRENT SUPPLIED TO PLATING TANK
DURING EACH MASS EMISSION TEST RUN
Test time Total current,
minutes (hours) ampere-hours
Run No. Inlet Outlet Inlet Outlet
1 192 (3.2) 192 (3.2) 9,600 9,600
2 120 (2.0) 120 (2.0) 6,000 6,000
3 120 (2.0) 120 (2.0) 10,800 10,800
4 192 (3.2) 192 (3.2) 9,600 9,600
5 120 (2.0) 120 (2.0) 6,000 6,000
12
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collection for the test runs when polypropylene balls were In the tank.
Each test run was interrupted for 5 to 15 minutes to change test ports.
13
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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 B.
In addition to the emission samples, grab samples of the plating
bath and mist eliminator washdown water were composited during each MM13B
run and analyzed using the same colorimetric procedures as 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 mfi. 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
gravimetrically. 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.
14
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TABLE 3-1. SCHEDULE OF ACTIVITIES
Date
(1989)
1/30
1/30
1/30
1/30
1/31
1/31
1/31
1/31
1/31
1/31
1/31
1/31
2/1
2/1
2/1
2/1
2/1
2/1
2/1
2/1
Sample
Tvoe
MM13Ba
SMb
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
11 series
10 series
1
1-2, 0-2 120
21 series
20 series
2
1-3, 0-3 120
31 series
30 series
3
1-4, 0-4 192
41 series
40 series
4
1-5, 0-5 120
51 series
50 series
5
Parameter
Measured
Cr+6
Cr*6
Cr+6
Cr+6
Cr+6
Cr+6
Cr+6
Cr+6
Cr+6
Cr+6
Cr+6
Cr+6
Cr+6
Cr+6
Cr+6
Cr+6
Cr+6
Cr+6-
Cr+6
Cr+6
a «= modified method 13B
b = screening method
15
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Inlet to the Mesh-Pad Mist Eliminator
Modified Method 1 SB-
Testing at this location was conducted under two conditions.
During the first three runs, the emissions from the plating bath were
uncontrolled. The fourth and fifth runs were conducted with two to three
layers of hollow polypropylene balls on the surface of the plating bath
to control emissions.
A summary of the flue gas conditions at this location are presented
in Table 3-2. The volumetric flowrates were consistent and averaged
92 dry standard cubic meters per minute (dscmm), (3,240 dry standard
cubic feet per minute, (dscfm)). The flue gas temperature averaged 23°C
(74°F) and the moisture content averaged 0.93 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, it was decided that the first and fourth MM13B
runs 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, it was
determined that the sample time per point could be reduced to 5 minutes.
The uncontrolled emissions (Runs 1-3) for each MM13B run were consistent
and averaged 4.42 mg/dscm (0.00193 gr/dscf). When polypropylene balls
were placed on the surface of the plating bath, emissions were consistent
and averaged 0.953 mg/dscm (0.000415 gr/dscf). A summary of the MM13B
sample volumes, analytical results and emission rates for this location
presented in Table 3-3.
Outlet from the Mist Eliminator
Modified Method 13B—
A summary of the flue gas conditions at this location are also
presented in Table 3-2. The volumetric flowrates were consistent and
16
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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
1/30/89
1/30/89
1/31/89
1/31/89
1/31/89
1/31/89
2/1/89
2/1/89
2/1/89
2/1/89
Volumetric Flowrate
ds cm/mi n dscf/min
87 3,080
98
94
105
92
103
94
104
93
104
3,460
3,300
3,710
3.250
3.640
3.320
3.680
3.270
3.680
Temperature
°C °F
23
21
23
21
24
22
23
19
23
20
74
70
74
69
76
71
73
67
74
68
% Moisture
1.10
1.07
0.84
0.77
0.94
0.90
0.79
0.43
1.00
0.59
% Isokinetic
98.2
95.5
94.7
98.5
93.4
98.1
97.4
107.3
97.9
108.0
17
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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,
Stack
dscf m
Vol time
Metered
dscf
Total
Cr+6
Mass
. ma
Concentration
mq/dscm
qr/dscf
Emission
ka/hr
Rates
Ib/hr
Without Balls
1-1 3.080
1-2 3,300
1-3 3,250
133.171
86.183
83.670
14.873
9.820
12.511
3.94 0.00172
4.02 0.00176
5.28 0.00231
0.0206 0.0454
0.0226 0.0498
0.0291 0.0642
With Balls
1-4
1-5
3,320
3,270
142.796
88.136
4.729
1.839
1.17 0.00051
0.74 0.00032
0.0066 0.0146
0.0041 0.0090
18
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averaged 103 dry standard cubic meters per minute (dscmm), (3,630 dry
standard cubic feet per minute, (dscfm)). The flue gas temperature
averaged 21°C (69°F) and the moisture content averaged 0.75 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, it was decided that the first and fourth 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"1"6. In order to collect a larger sample and
assure a detectable Cr+6 concentration, nozzle size was increased
from 0.235 inches to 0.295 inches on outlet runs 4 and 5. Following the
analysis of the sample, it was determined that the sample time per point
could be reduced to 5 minutes, for a total sample time of 120 minutes.
The emissions as measured in each MM13B run were consistent and averaged
0.0380 mg/dscm (0.00002 gr/dscf). A summary of the MM13B sample volumes,
analytical results and emission rates for this location is presented in
Table 3-4.
The Cr+6 control efficiency of the polypropylene balls on the
surface of the plating tank averaged 74.9%. This value was determined by
comparing the mass flowrates for runs 1-1 vs. 1-4 and run 1-2 vs. 1-5.
The Cr+6 removal efficiency for the mist eliminator alone was 98.9%
(no polypropylene balls on plating tank surface and based on runs 1-3).
The efficiency of the mist eliminator operated in combination with the
polypropylene balls (runs 4-5) was 96.3%. A summary of removal
efficiencies for the system is presented in Table 3-5.
PLATING TANK SOLUTIONS
During each MM13 run, grab samples of the plating bath solution were
collected and composited. The samples were analyzed for Cr"1"6
concentration. The results from these analyses are presented in
Table 3-6.
19
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Without Balls
0-1 3,460
0-2 3.710
0-3 3,640
TABLE 3-4. SUMMARY OF SAMPLE VOLUMES, ANALYTICAL RESULTS AND
EMISSION RATES FOR THE MESH-PAD MIST ELIMINATOR OUTLET
Run No.
Stack
dscfm
Vol ume
Mete red
dscf
Total Mass
Cr+6. ma
Concentration
mq/dscm qr/dscf
Emission Rates
kq/hr Ib/hr
139.880
96.812
94.613
0.1740 0.0439 0.00002
0.0957 0.0349 0.00002
0.1369 0.0511 0.00002
0.000258 0.000569
0.000220 0.000485
0.000316 0.000697
With Balls
0-4 3,680
0-5 3,680
263.655
165.758
0.2370 0.0317 0.00001
0.1327 0.0283 0.00001
0.000199 0.000438
0.000177 0.000389
20
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TABLE 3-5. SUMMARY OF Cr+6 REMOVAL EFFICIENCIES
Run No. Cr+6 Emission Rate Ib/hr Cr+6 Removal Efficiency
1-1 0.0454
0-1 0.000569 98.7%
1-2 0.498
0-2 0.000485 99.0%
1-3 0.0642
0-3 0.000297 98.9%
1-4 0.0146
0-4 0.000438 96.9%
1-5 0.0090
0-5 0.000389 95.7%
Polypropylene Ball Efficiency 74.9%
(Average 1-1 vs. 1-4 and 1-2 vs. 1-5)
Mist Eliminator Efficiency 98.9%
(Runs 1-3)
Mist Eliminator Efficiency With Polypropylene Balls 96.3%
On Tank Surface (Runs 4-5)
21
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TABLE 3-6. SUMMARY OF PLATING SOLUTION
& WASHDOWN WATER ANALYTICAL RESULTS
Run No. Cr+6 Concentration,
Plating Solution
1-1 106,745
1-2 111,620
1-3 111,620
1-4 108,277
1-5 106,627
Mist Eliminator Washdown Water
1/30/89 48,369
1/31/89 31,228
2/1/89 15,520
22
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MIST ELIMINATOR RINSE
Prior to the start of the sampling program, the mist eliminator was
rinsed with fresh water. The mist eliminator was rinsed daily and a
sample of washdown water was collected and analyzed for Cr"1"6
concentrations. The results of these analyses were presented in
Table 3-6.
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 Traverses for Stationary
Sources" was used to select representative measurement sites. At the
inlet, the measurement site was located in a 15.5 inch ID circular
horizontal duct 36.8 inches (2.4 stack diameters) downstream of the
nearest flow disturbance (90° elbow) and 9.2 inches (0.6 stack diameters)
upstream of the nearest flow disturbance (mist eliminator inlet).
According to EPA Method 1 criteria, this location required 24 sample
traverse points, 12 along each of two perpendicular diameters. Table 4-1
shows the traverse point locations.
At the mist eliminator outlet, the measurement site was located in a
15.8 inch ID circular vertical stack 11.3 feet (8.6 stack diameters)
downstream of the nearest flow disturbance (ID fan) and approximately
29 feet (22 stack diameters) upstream of the nearest flow disturbance
(atmosphere). According to EPA Method 1 criteria, this location required
12 sample traverse points, 6 along each of two perpendicular diameters.
Table 4-1 shows the traverse point locations.
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
24
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TABLE 4-1. SAMPLE TRAVERSE POINT LOCATIONS FOR THE MESH-PAD MIST
ELIMINATOR INLET AND OUTLET
Traverse Location (inches)
Point Mist Eliminator Mist Eliminator
No. Inlet Outlet
1 0.5 0.9
2 1.0 2.5
3 1.8 4.9
4 2.7 11.4
5 3.9 13.7
6 5.5 15.3
7 10.0
8 11.6
9 12.8
10 13.7
11 14.5
12 15.0
25
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point. If the point reading was not zero at 0-degree reference, the
pi tot was rotated until a null reading was obtained. The value of the
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 (nonaxial) flow conditions in the
duct. Both of these sites indicated acceptable flow patterns so that
extraction of representative samples from these sites was performed using
normal sampling procedures.
Test Methods
Velocity and static pressures, moisture content, and temperature
were measured prior to sampling, in 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
impingers. The first, third and fourth impingers were Greenburg-Smith
design, modified by replacing the tip with a 1/2-in. inside diameter
glass tube extending to 1/2-in. from the bottom of the flask. The second
impinger was a Greenburg-Smith impinger with the standard tip. The first
and second impingers contained lOOmfi, 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 initially set at 8 minutes per point (192
minute total sample time) and reduced to 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.
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The impingers 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 a clean
area of the plant. 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 calculator. The calculations were also
performed by the EPA Task Manager.
The analytical method entitled "Draft Method - Determination of
Hexavalent Chromium in Dry Particulate Emissions from Stationary Sources"
was used as a "guideline" in conducting the analyses. This method is
currently under development by the EPA and is presented in Appendix B.
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.
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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 ma, 5 mfc, 7 ma, 10 ma, 15 ma and 20 ma of the
5 vg/mi working standard. The spectrophotometer calibration
factor, KC, was calculated as follows:
A + 2.5A + 3.5A + 5A + 7.5A + IDA
1 2 34 56
Kc = 10 2 a—;—; 1—\
Al + A,a + A3 + A« + A5 + ^6
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.
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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 in 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.
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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 in Table 5-1.
H20 Blanks—
A distilled water blank was obtained from the wash bottles and
analyzed in the same manner as the emission samples.
Duplicate Samples
One sample for every 10 samples analyzed was a duplicate, e.g., if
24 samples were analyzed, 3 duplicate samples would be analyzed. The
analytical results for the duplicated samples are presented in Table 5-1.
Standards
Daily, 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 C.
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.
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TABLE 5-1. SUMMARY OF ANALYTICAL RESULTS FOR QA/QC SAMPLES AND BLANKS
Sample No. Date
75 p/lOO mQ,
0-1
Plating Sol 1/30
50 pg/mfi,
1-3
75 pg/100 mfi.
0-4
50 P9/100 mJl
1-2
100 yg/ioo mfi,
%
100pg/100 mfc
0-2
Blanks
0.1N NaOH
(1989)
1/30
1/31
1/31
1/31
1/31
2/1
2/1
2/1
2/1
2/1
2/1
2/1
1/30
Type of Sample
Duplicate Standard Total JW C1""1"6
X 75.2
X 177.6
X 106,745 pg/mfi, "112,015 pg/mfi.
X 50.9
X 12,510.9 *12,510.9
X 75.4
X 227.6 *237.04
X 50.7
X 9699.0 "9820.4
X 99.4
X 95.6
X 101.4 "95.7
0.00
* Original values against which duplicate results are to be compared.
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SAMPLING TRAIN COMPONENTS
The equipment used in this test program, including nozzles, pitot
tubes, dry gas meters, orifices,, and thermocouples were uniquely identified
and were calibrated in 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 in Appendix D.
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 in 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 PEER 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.
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