EPA Method 26A Determination Of Hydrogen Halide And Halogen Emissions From Stationary Sources Isokinetic Method
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ID： |
F36142340BE74E1D82816DF9E6E968FA |
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文件大小(MB)： |
0.25 |
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页数： |
30 |
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文件格式： |
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日期： |
2000-2-12 |
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购买： |
文本摘录（文本识别可能有误，但文件阅览显示及打印正常，pdf文件可进行文字搜索定位）：
1359,METHOD 26A - DETERMINATION OF HYDROGEN HALIDE AND,HALOGEN EMISSIONS FROM STATIONARY SOURCES,ISOKINETIC METHOD,NOTE: This method does not include all of the,specifications (e.g. equipment and supplies) and procedures,(e.g. sampling and analytical) essential to its performance.,Some material is incorporated by reference from other,methods in this part. Therefore, to obtain reliable,results, persons using this method should have a thorough,knowledge of at least the following additional test methods:,Method 2, Method 5, and Method 26.,1.0 Scope and Application.,1.1 Analytes.,Analytes CAS No.,Hydrogen Chloride (HCl) 7647-01-0,Hydrogen Bromide (HBr) 10035-10-6,Hydrogen Fluoride (HF) 7664-39-3,Chlorine (Cl2) 7882-50-5,Bromine (Br2) 7726-95-6,1.2 This method is applicable for determining,emissions of hydrogen halides (HX) [HCl, HBr, and HF] and,halogens (X2) [Cl2 and Br2] from stationary sources when,specified by the applicable subpart. This method collects,the emission sample isokinetically and is therefore,particularly suited for sampling at sources, such as those,1360,controlled by wet scrubbers, emitting acid particulate,matter (e.g., hydrogen halides dissolved in water droplets).,1.3 Data Quality Objectives. Adherence to the,requirements of this method will enhance the quality of the,data obtained from air pollutant sampling methods.,2.0 Summary of Method.,2.1 Principle. Gaseous and particulate pollutants,are withdrawn isokinetically from the source and collected,in an optional cyclone, on a filter, and in absorbing,solutions. The cyclone collects any liquid droplets and is,not necessary if the source emissions do not contain them;,however, it is preferable to include the cyclone in the,sampling train to protect the filter from any liquid,present. The filter collects particulate matter including,halide salts but is not routinely recovered or analyzed.,Acidic and alkaline absorbing solutions collect the gaseous,hydrogen halides and halogens, respectively. Following,sampling of emissions containing liquid droplets, any,halides/halogens dissolved in the liquid in the cyclone and,on the filter are vaporized to gas and collected in the,impingers by pulling conditioned ambient air through the,sampling train. The hydrogen halides are solubilized in the,acidic solution and form chloride (Cl-), bromide (Br-), and,fluoride (F-) ions. The halogens have a very low solubility,1361,in the acidic solution and pass through to the alkaline,solution where they are hydrolyzed to form a proton (H+),the halide ion, and the hypohalous acid (HClO or HBrO).,Sodium thiosulfate is added to the alkaline solution to,assure reaction with the hypohalous acid to form a second,halide ion such that 2 halide ions are formed for each,molecule of halogen gas. The halide ions in the separate,solutions are measured by ion chromatography (IC). If,desired, the particulate matter recovered from the filter,and the probe is analyzed following the procedures in,Method 5.,NOTE: If the tester intends to use this sampling,arrangement to sample concurrently for particulate matter,the alternative Teflon probe liner, cyclone, and filter,holder should not be used. The Teflon filter support must,be used. The tester must also meet the probe and filter,temperature requirements of both sampling trains.,3.0 Definitions. [Reserved],4.0 Interferences.,4.1 Volatile materials, such as chlorine dioxide,(ClO2) and ammonium chloride (NH4Cl), which produce halide,ions upon dissolution during sampling are potential,interferents. Interferents for the halide measurements are,the halogen gases which disproportionate to a hydrogen,1362,halide and an hypohalous acid upon dissolution in water.,The use of acidic rather than neutral or basic solutions for,collection of the hydrogen halides greatly reduces the,dissolution of any halogens passing through this solution.,4.2 The simultaneous presence of both HBr and Cl2 may,cause a positive bias in the HCl result with a corresponding,negative bias in the Cl2 result as well as affecting the,HBr/Br2 split.,4.3 High concentrations of nitrogen oxides (NOx) may,produce sufficient nitrate (NO3,-) to interfere with,measurements of very low Br- levels.,4.4 There is anecdotal evidence that HF may be,outgassed from new Teflon components. If HF is a target,analyte then preconditioning of new Teflon components, by,heating, should be considered.,5.0 Safety.,5.1 Disclaimer. This method may involve hazardous,materials, operations, and equipment. This test method may,not address all of the safety problems associated with its,use. It is the responsibility of the user to establish,appropriate safety and health prac……
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