1、Designation: D 6735 01Standard Test Method forMeasurement of Gaseous Chlorides and Fluorides fromMineral Calcining Exhaust SourcesImpinger Method1This standard is issued under the fixed designation D 6735; the number immediately following the designation indicates the year oforiginal adoption or, in
2、 the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.INTRODUCTIONThe bias and precision statements included in Section 14 of this test method are b
3、ased on field testmeasurements at limestone calcining sources. Procedures for assessing the test-specific bias and theprecision at each source are included in the body of the method.Additional optional procedures are included in Appendix X1 that can be used to demonstrate thebias and precision of th
4、e method for specific source categories. These procedures were used to developthe bias and precision statements included in Section 14 and may be applied when using the methodat sources where no previous test data have been acquired.1. Scope1.1 This method will measure the concentration of gaseoushy
5、drochloric and hydrofluoric acids, and other gaseous chlo-rides and fluorides that pass through a particulate matter filtermaintained at 177C (350F). This method is specific forsampling combustion effluent from mineral calcining industriesand other stationary sources where the reactive/adsorptivenat
6、ure of the particulate matter may affect measurements.1.2 This method utilizes ion chromatography to quantify theaqueous samples, and thus measures only the C1-and F-ions.1.3 Based on a one-hour sampling run, the method willprovide results of known accuracy and precision for chlorideand fluoride in-
7、stack concentrations of 0.5 ppm (v) dry orgreater. Extending the run duration and sampling a greatervolume of effluent will extend the range to lower concentra-tions.1.4 This method includes optional post-test quality assur-ance procedures to assess the bias of the test results, andoptional paired s
8、ample train runs to assess the precision of testresults.2. Referenced Documents2.1 ASTM Standards:2D 1356 Terminology Relating to Sampling and Analysis ofAtmospheresD 2986 Practice for Evaluation of Air Assay Media by theMonodisperse DOP Dioctyl Phthalate Smoke TestD 3195 Practice for Rotameter Cali
9、brationD 6348 Test Method for Determination of Gaseous Com-pounds by Extractive Direct Interface Fourier TransformInfrared (FTIR) Spectroscopy2.2 EPA Standards:3Method 1Sample and Velocity Traverses for StationarySourcesMethod 2Determination of Stack Gas Velocity and Volu-metric Flow Rate (Type S Pi
10、tot Tube)Method 3Gas Analysis for Carbon Dioxide, Oxygen,Excess Air, and Dry Molecular WeightMethod 4Determination of Moisture Content in StackGasesMethod 301Field Validation of Pollutant MeasurementMethods from Various Waste Media3. Terminology3.1 See Terminology D 1356 for definition of terms used
11、 inthis test method.3.2 Definitions of Terms Specific to This Standard:3.2.1 analyte spike, nthe optional procedure contained inthis method to assess bias attributed to the measurementsystem. The analyte spike procedure consists of adding a1This test method is under the jurisdiction of ASTM Committe
12、e D22 onSampling and Analysis of Atmospheres and is the direct responsibility of Subcom-mittee D22.03 on Ambient Atmospheres and Source Emissions.Current edition approved December 10, 2001. Published February 2002.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM C
13、ustomer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3United States Environmental Protection Agency Code of Federal Regulations,40 CFR Parts 60 and 63, available from the Government Printing Office, W
14、ashing-ton, DC.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.known amount of the certified compressed gas into theimpinger train upstream of the particulate filter after the end ofa run.3.2.2 blank train, nan impinger train that is
15、 assembledand recovered but does not collect effluent gas. The blank trainprovides an estimate of the amount of contamination that canoccur during a field test.3.2.3 certified compressed gas, nan HCl or HF gasstandard that is certified by the manufacturer to a known degreeof accuracy. For HCl and HF
16、 compressed gas standards theaccuracy is often certified to 510 % of the certified value.3.2.4 conditioning run, na sampling run conducted beforethe first run of the test series. The impinger contents from theconditioning run are not analyzed nor included in the testresults.3.2.5 cylinder gas analys
17、is, na procedure to verify theconcentration of the certified compressed gas and to providethe direct cylinder value. See 11.2.7.4.3.2.6 direct cylinder value, nthe value of the certifiedcylinder gas, or the value obtained from conducting thecylinder gas analysis. See 11.2.7.4.3.2.7 hazardous air pol
18、lutants (HAPs), napproximately188 compounds or groups of compounds identified in Title IIIof the Clean Air Act Amendments.3.2.8 impinger train, na series of midget impingers con-nected together by glass or TFE-fluorocarbon u-tubes.3.2.9 midget impinger, ncylindrical glass (or other appro-priate mate
19、rial) containers that hold approximately 50 mL.3.2.10 mineral calcining industry, nindustries that usethermal devices to remove CO2and other compounds fromnon-ferrous mineral material.3.2.11 paired runs, ntwo impinger trains operated simul-taneously at the same sampling location.3.2.12 partition rat
20、io, nthe amount of a substance atequilibrium with its gas and particulate phases.3.2.13 proportional controllers, na temperature controldevice that uses a sensor to make small adjustments to thepower output. These types of controllers prevent wide fluctua-tions in the temperature of the heated measu
21、rement systemcomponents.3.2.14 reagent blank, na 2030 mL sample of the 0.1 NH2SO4impinger solution that is diluted to 100 mL.3.2.15 sampling system leak check, na procedure thattests the sampling system for negative pressure leaks.3.2.16 spiked train, na train in which HCl(g) or HF(g) hasbeen added
22、after the test run to determine measurement systembias.3.2.17 “u” tubes, nconnecting tubes constructed of eitherglass or TFE-fluorocarbon to assemble the impinger train.3.2.18 volatile compounds, ncompounds that are gases atthe effluent temperature.4. Summary of Test Method4.1 Sampling:4.1.1 This me
23、thod involves collecting an integrated sampleof stack gas in a series of five midget impingers. Two of thefive impingers contain 0.1 N H2SO4, two are empty and onecontains silica gel.4.1.2 Sampling is conducted from a single point within thestack or duct at a constant sampling rate of 2 L/min (65 %)
24、 fora period of at least one h per sample run.4.1.3 The sampling system heated components must bemaintained at a temperature of 350 6 15F (177 6 8C). Thesampling system is conditioned before conducting the first runby sampling 120 L of stack gas at 2 L/min, and then discardingthe impinger solutions.
25、4.1.4 A test is comprised of three or more sample runs.NOTE 1The conditioning run is to minimize HCl and/or HF adsorp-tion during the ensuing sampling runs by passivating active sites in theprobe and filter box components.NOTE 2The impingers from the conditioning run are rinsed thor-oughly with deio
26、nized water before recharging to start the first run.Rinsing the probe and filter assembly must not be performed.NOTE 3The particulate matter from mineral calcining facilities ad-sorbs HCl and HF to varying degrees. The amount of adsorption dependson process parameters and the physical/chemical prop
27、erties of the dust.Measures such as turning the probe nozzle opening away from the stackor duct flow minimize collection of particulate matter on the filter materialand thus reduce the adsorption of HCl and HF. Other measures that reducecollection of particulate matter are acceptable. Such measures
28、includeinstalling a shrouded large pore sintered filter ( 20 microns) on the endof the probe. This apparatus will reduce collecting particulate matter whileallowing gases and small particles to enter.4.2 Analysis:4.2.1 Quantification of chloride and fluoride ions is accom-plished by analyzing an ali
29、quot of the impinger solution usingion chromatography.4.2.2 The total mass of chloride or fluoride ions collected inthe impinger solution sample is a product of the ion chromato-graphic (IC) output in either mg or g and the total volume ofthe sample. For example, if the IC analysis for chloride is 0
30、.02mg, and the total sample volume is 100 mL, then the total massof chloride collected for the run is equivalent to 2 mg(assuming a 1-mL injection into the IC).4.2.3 Use the following equation to determine the total massof chloride or fluoride ions in the sample.IC/IV! * SV! 5 mg of ion in total sam
31、ple (1)where:IC = ion chromatographic results in mg,IV = volume of sample injected into ion chromatograph inmL, andSV = sample volume in mL.4.2.4 The equivalent in-stack concentration of the sample isequivalent to the mg catch of anion in the impinger solutionsample divided by the gas sample volume
32、at standard condi-tions.5. Significance and Use5.1 This field-test method provides chloride and fluorideconcentration results on a dry basis. Concentration data forgaseous chlorides and fluorides are assumed to be hydrochloricacid gas, and hydrofluoric acid gas when calculating massemission rates.5.
33、2 Mass emission rates of HCl and HF can be calculated ifthe effluent volumetric flow rate is known. Volumetric flowrates can be calculated by conducting EPA Methods 14 ortheir equivalents.D67350125.3 This field test method provides data having bias andprecision for HCl consistent with the values in
34、Section 14.Inaddition, the test-specific bias can be assessed for each test byconducting the post-test quality assurance check. The proce-dure is identified as optional, and the performance of thisprocedure depends on the test specific data quality objectives,and end use of the data.5.4 The test-spe
35、cific precision may be determined by con-ducting paired-runs. Paired runs aid in identifying possiblesuspect data and provide backup in the event one train isinvalidated. Performing paired runs depends on the test-specific data quality objectives.5.5 The reaction of gaseous HCl with ammonia (NH3)tof
36、orm solid ammonium chloride (NH4Cl) is well known. Atstack temperatures common to the exits of baghouses and ESPsat mineral calcining facilities (that is, 250 to 450F or 121 to232C), an equilibration between the gaseous HCl/NH3, thecondensed NH4Cl(s), and the effluent particulate matter canexist. It
37、 is impossible to know the exact partition ratio betweenthe gas and particulate phases of these compounds in thesampling system. Furthermore, it is very difficult to control theeffects of these partitioning reactions within the various sam-pling system components.NOTE 4Use of this method is cautione
38、d when trying to quantify HCl(g) in the presence of ammonium chloride and ammonia.6. Interferences6.1 Sampling Interferences:6.1.1 The particulate matter (dust) from mineral calciningindustries adsorbs HCl and HF to a varying degree, which willreduce the amount of gaseous chloride and fluoride ions
39、thatreach the impinger solutions.6.1.2 Condensed water vapor in the probe and filter area dueto heater failure or poor heating will reduce the amount ofgaseous chloride and fluoride ions reaching the impingersolutions.6.1.3 Improper filter seating in the filter holder will allowleakage of particulat
40、e matter into the impinger solutions. Thismay result in more chloride and fluoride ions reaching theimpinger solutions.6.2 Analytical InterferencesEnsuring that the chromato-graphic conditions are optimized for separating chloride andfluoride from other ions minimizes analytical interferences.7. App
41、aratus7.1 SamplingSee Fig. 1.7.1.1 Sample Probe Assembly, including a probe liner ofborosilicate glass, stainless steel, or TFE-fluorocarbon of (1)sufficient length to reach the gas sampling point, (2) of physicalintegrity to minimize adsorption of HCl and/or HF, and (3)heated and controlled to sust
42、ain the sample temperature at 3506 15F (177 6 8C). The internal diameter of the probe linershould be between 0.25-0.5 in. (0.1-2 cm). The probe assemblyshall minimize collection of particulate matter but allow gasesand small particles to pass.NOTE 5The assembly could consist of an in-stack large por
43、e sinteredfilter (20 microns) with a shroud, or a nozzle that is positioned awayfrom the flow stream.NOTE 6A specially designed probe that utilizes fore and aft indepen-dent heater and heater controllers has proven to be capable of maintainingthe 350F temperature throughout the length of the probe.
44、This is crucialwhen a portion of the probe is inserted into a hot stack but the remainderof the probe is out of the stack at a much cooler relative temperature. Useof this probe design will minimize or eliminate moisture condensation andthus adsorption of HCl and HF.7.1.2 Particulate Filters, rated
45、at 0.3 m (or less), andhaving an efficiency of 95 % or greater in accordance withPractice D 2986. The filters are placed immediately after theheated probe in a heated and temperature-controlled compart-ment. A TFE-fluorocarbon-glass filter (75 % TFE-fluorocarbon, 25 % glass), or an ultra high purity
46、 quartz filtermust be used to remove particulate matter.7.1.3 Particulate Filter Holders, filter holders and supportsshould be made out of TFE-fluorocarbon or TFE-fluorocarboncoated stainless steel.NOTE 7The TFE-fluorocarbon filter holder and filter support must becapable of withstanding the 350F (1
47、77C) filter temperature.7.1.4 Impingers, five midget impingers (about 50 mL vol-ume) with straight stems and with leak-free glass connections.The first and fourth impingers in the train are empty, the secondtwo impingers each contain 15 mL of 0.1 N H2SO4absorbingsolution, and the fifth contains sili
48、ca gel. Silicone grease maybe use to aid joining the impinger connections.7.1.5 Silica Gel (or equivalent), used to protect the dry gasmeter and pump. The silica gel is not part of the sample.7.1.6 U-Tubes, glass or TFE-fluorocarbon connecting tubesto assemble the impinger train.7.1.7 Leak Free Samp
49、le Connector, sample line to connectthe silica gel impinger to the pump and gas-metering device.7.1.8 Rate Meter, flow measurement device sufficient tomaintain constant rate sampling at 2 L/min 65 % or less.7.1.9 Volume Meter, capable of measuring the volume ofgas sample at a flow rate of 2 L/min with an accuracy of 62%,and a resolution of 0.01 L or better.7.1.10 Pump, leak free diaphragm type or equivalent ca-pable of maintaining a sampling rate of 2 L/min at the staticpressure encountered in the stack or duct.7.1.11 Thermocouples or O
