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 ------- 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 ------- 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 ------- 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 ------- 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. ------- (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. ------- 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. ------- 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. ------- 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. ------- 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 ------- STACK FAN MESH-PAD MIST ELIMINATOR PLATING TANK Figure 2-2. Air pollution control system. ------- 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. ------- 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 ------- 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 ------- 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 ------- 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 ------- 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 ------- 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 ------- 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 ------- 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 ------- 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 ------- 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 ------- 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 ------- 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 ------- 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 ------- 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 ------- 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 ------- 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 ------- 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 ------- 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. 26 ------- 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. 27 ------- 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. 28 ------- 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. 29 ------- 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. 30 ------- 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. 31 ------- 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. 32 ------- |