1、Designation: D4323 15Standard Test Method forHydrogen Sulfide in the Atmosphere by Rate of Change ofReflectance1This standard is issued under the fixed designation D4323; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of
2、last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the automatic continuous deter-mination of hydrogen sulfide (H2S) in the atmosphere or ingaseo
3、us samples in the range from one part per billion byvolume (1 ppb/v) to 3000 ppb/v. Information obtained may beused for air-pollution studies and to monitor for emissionsources.1.2 The range may be extended by appropriate dilutiontechniques or by equipment modification.1.3 The values stated in SI un
4、its are to be regarded asstandard. The values given in parentheses are mathematicalconversions to inch-pound units that are provided for informa-tion only and are not considered standard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is t
5、heresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. (See Section 9 forspecific safety precautionary statements.)2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for
6、Reagent WaterD1356 Terminology Relating to Sampling and Analysis ofAtmospheresD2420 Test Method for Hydrogen Sulfide in LiquefiedPetroleum (LP) Gases (Lead Acetate Method)D2725 Test Method for Hydrogen Sulfide in Natural Gas(Methylene Blue Method) (Withdrawn 1996)3D3609 Practice for Calibration Tech
7、niques Using Perme-ation TubesD4084 Test Method for Analysis of Hydrogen Sulfide inGaseous Fuels (Lead Acetate Reaction Rate Method)D4323 Test Method for Hydrogen Sulfide in theAtmosphereby Rate of Change of ReflectanceD6299 Practice for Applying Statistical Quality Assuranceand Control Charting Tec
8、hniques to Evaluate AnalyticalMeasurement System PerformanceD6792 Practice for Quality System in Petroleum Productsand Lubricants Testing Laboratories3. Terminology3.1 DefinitionsFor definitions of terms used in this testmethod, refer to Terminology D1356.4. Summary of Test Method4.1 Hydrogen sulfid
9、e is determined by use of the reaction ofH2S with lead acetate-impregnated paper tape and by compar-ing a reading of an unknown sample with that of a knownstandard using a differential colorimetric detection. Detectionof the rate of change of reflectance provides measurement inppb/v ranges with an a
10、nalysis time appropriate for the appli-cation. (See Fig. 1.) Sample gas is passed through a flowmeterand a humidifier; then across lead acetate-treated paper tape. Aconstant humidity is required for a constant reaction rate ofH2S with lead acetate. H2S reacts with lead acetate to form abrown stain o
11、n the paper. The resultant change in reflectance isdetected by a photon detection system. The rate of change ofreflectance is proportional to H2S concentration. The analyzeris composed of an optical system, a photon detection system, asignal differentiation system of first order, and a signal output
12、system.5. Significance and Use5.1 Hydrogen sulfide is an odorous substance which isoffensive even at low concentrations in the atmosphere andtoxic at higher levels. It may be a product of biologicalprocesses in the absence of oxygen, as may occur in municipalgarbage landfills. It is emitted from geo
13、thermal sources, occursin oil and gas, and may be emitted from industrial processes.Measurement is required for air pollution studies, for pollutioncontrol, and for plume characterization. This test method isintended for hydrogen sulfide content up to 3000 ppbv.1This test method is under the jurisdi
14、ction of ASTM Committee D22 on AirQuality and is the direct responsibility of Subcommittee D22.03 on AmbientAtmospheres and Source Emissions.Current edition approved April 1, 2015. Published April 2015. Originallyapproved in 1984. Last previous edition approved in 2009 as D4323 84 (2009).DOI: 10.152
15、0/D4323-15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical stan
16、dard is referenced onwww.astm.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1Measurement of hydrogen sulfide above this concentration ingaseous fuels, carbon dioxide or other gaseous matrices isdescribed in Test Method D4084. Equ
17、ipment described issuitable for fixed site or for mobile monitoring.6. Interferences6.1 In applications of this method, high levels of somecompounds can result in instrument response. Methylmercaptan, when 1000 times the H2S concentration can affectresponse equal to H2S response. Arsine, phosphine,
18、and freesulfur have been reported as causing response. The operatorshould take required precautions if the above materials areexpected to be present in the sample.6.2 In the event SO2may be present, a solution of bariumacetate may be substituted for the acetic acid solution to scrubout the SO2compon
19、ent without removing H2S. Use 3 % byweight barium acetate in deionized water.4Hydrogen sulfideand SO2react spontaneously and prepared samples cannot bestored more than a few minutes7. Apparatus57.1 Rate-of-Reaction H2S AnalyzerSample is passedacross a lead acetate-treated surface causing a reflectan
20、cechange. Hydrogen sulfide is determined by measuring the rateof change of reflectance resulting from darkening when leadsulfide is formed. Equipment consists of a flowmeter,humidifier, sensing surface exposure chamber, optical system,and electronic system. (See Fig. 1.) A complete analysis resultsf
21、rom use of the rate of change of color rather than magnitudeof cumulative color development. The electronic system pro-vides an output that is proportional to the derivative of thephotocell signal, caused by a reflectance change, and this ratemeasurement is a measure of H2S concentration.Anew sectio
22、nof sensing material is drawn into the sensing chamber toprovide a new independent measurement.7.2 RecorderA method of recording the electronic signalis required. A printer or other output means, such as amicroprocessor, data logger or data collection system (DCS),can be used.7.3 Reference Gas Prepa
23、ration:7.3.1 MixingA calibrated 10-L cylinder having a movablepiston for use in making volumetric mixtures of gases in theppb/v range may be used. Materials of construction must beinert to H2S and not lead to a deterioration of prepared samples.A cylinder of acrylic lubricated with silicone grease a
24、nd usinga silicone O-ring has been found to be suitable. Concentrationremains stable to within 1 % over a 1-h period. These devicesare not needed when the permeation tube method of dynamicmixing is used to prepare the reference sample since thismethod will generate a reference mixture.7.3.2 Hypoderm
25、ic SyringeGas-tight syringes of 10 and50-l capacity. A side port is convenient for purging. AvoidLuer tip syringes made of plated brass as H2S reacts with brass.Other convenient small volume measurement devices such as amicrolitre valve may be used.4Smith, A. F., Jenkins, D. G., and Cunningworth, P.
26、 E., Journal of AppliedChemistry, Vol 11, 1961, pp. 317.5Kimbell, C. L. and Drushel, H. V., “Trace Sulphur Determination in PetroleumFractions,” Analytical Chemistry, Vol 50, 1978, p 26.FIG. 1 Typical Rate of Change of Reflectance Type H2S SystemD4323 1527.3.3 PumpA sample pump capable of providing
27、500mL/min flow at approximately 35 kPa 5 psi. The pumpwetted parts must be inert to H2S and not lead to a deteriorationof the sample.8. Reagent and Materials8.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise noted, all reagents shallconform to the specification
28、s of the Committee on AnalyticalReagents of the American Chemical Society, where suchspecifications are available.68.2 Acetic Acid Solution (50 mL/L)Dilute 50 mL ofglacial acetic acid (CH3COOH), reagent grade, to make 1 L ofsolution using Type III water prepared as described in Speci-fication D1193.
29、8.3 Sensing TapePrepare sensing tape as described in TestMethod D2420 or use commercial sensing tape6that has beenprepared in a similar manner. Keep sensing tape in a sealedcontainer to prevent exposure to ambient H2S.8.4 Hydrogen Sulfide (99.5 %)Commercially availableH2S has been found to be insuff
30、iciently pure. Purity certifica-tion is recommended or use of H2S generators using perme-ation devices may be used. Alternatively, a certified H2Smixture at concentrations as low as 1000 ppbv can be obtainedfrom a gas standard vendor in an air or nitrogen matrix. Thesemixtures can be either a primar
31、y standard, which is then dilutedto the desired H2S concentration using a 10-L cylinder with apiston, or a standard in a pressurized cylinder containing thedesired H2S concentration. Because of the potential fordegradation, H2S mixtures obtained from a gas standardvendor must be properly stored and
32、used only within the statedcertification period.8.4.1 Compressed Gas StandardsThe protocol for com-pressed gas standards contained in Appendix X3 can be used toensure uniformity in compressed gas standard manufacture andprovide for traceability to a NIST or other standard referencematerials.8.4.1.1
33、Compressed gas standard regulators must be appro-priate for the delivery of sulfur gases and attached fittings mustbe passivated or inert to sulfur gases.8.4.2 Permeation DevicesHydrogen Sulfide standards canbe prepared using a permeation tube gravimetrically calibratedand certified at a convenient
34、operating temperature.At constanttemperature, calibration gases covering a wide range of con-centration can be generated by varying and accurately measur-ing the flow rate of diluent gas passing over the tubes. Thesecalibration gases are used to calibrate the analyzer8.4.2.1 Permeation System Temper
35、ature ControlPermeation devices are maintained at the calibration tempera-ture within 0.1C.8.4.2.2 Permeation System Flow ControlThe permeationflow system measures diluent gas flow over the permeationtubes within 62 percent.8.4.2.3 Permeation tubes are inspected and weighed to thenearest 0.01 mg on
36、at least a monthly basis using a balancecalibrated against NIST traceable “S” class weights or theequivalent. Analyte concentration is calculated by weight lossand dilution gas flow rate as in accordance with PracticeD3609. These devices are discarded when the liquid contentsare reduced to less than
37、 ten percent of the initial volume orwhen the permeation surface is unusually discolored or other-wise compromised. Used permeation tubes should be disposedof in accordance with local, state, or federal environmentalregulations, or combination thereof.8.5 Dilution GasA chemically pure grade or purif
38、ied gassimilar to the gas to be sampled, H2S-free. Mixture can beprepared using the 10-L cylinder described in 7.3.1.8.6 Lead Acetate Sensing PaperPrepare in accordancewith Test Method D2420, using appropriate size strips anddrying in an H2S-free environment. Commercially availabletest paper has bee
39、n found satisfactory. Used Lead AcetateSensing Paper should be disposed of in accordance with local,state, or federal environmental regulations, or combinationthereof.9. Hazards9.1 Hydrogen Sulfide contained in lecture bottles, perme-ation tubes or compressed gas cylinders may be flammable andharmfu
40、l or fatal if ingested or inhaled. Hydrogen sulfide istoxic at levels above 10 000 ppb/v. Use only under anappropriate fume hood. Use protective glasses if liquid H2Sincylinders is handled. Sense of smell may be lost on exposure toH2S and is unreliable as a warning of danger. (See 6.1 and 6.2on Inte
41、rferences.)9.2 Lecture bottles, permeation tubes and compressed gasstandards should only be handled in well ventilated locationsaway from sparks and flames. Improper handling of com-pressed gas cylinders containing air, nitrogen or hydrocarbonscan result in explosion. Rapid release of nitrogen or hy
42、drocar-bon gasses can result in asphyxiation.9.3 Compressed air supports combustion.9.4 Concentrated acetic acid fumes are an irritant and cancause damage to skin and mucus membrane. Handle carefullyto avoid injury.9.5 Lead acetate is a cumulate poison; wash hands afterhandling and do not breathe an
43、y dust containing lead acetate.10. Sampling10.1 Sample lines and containers must not absorb sampleH2S. Suitable materials are fluorocarbon resins, aluminum,borosilicate glass, silica lined metal tubing, and suitableinactive acrylic. Stainless steel (Type 316) may be used whenrequired by regulations
44、but is not preferred.10.2 Avoid materials containing copper, brass, or havingpetroleum lubricant coatings.6Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see
45、 Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,MD.D4323 15311. Calibration and Standardization11.1 Reference StandardReference standards are preparedby volumetr
46、ic measurement at the time the reference materialis to be used. This minimizes deterioration of the sample. Thepermeation tube method or compressed gas cylinders certifiedas to concentration by the manufacturer may be used as areference standard. Small volumes of pure H2S are measuredusing a gas-tig
47、ht syringe. Dilution gas is measured using a10-L graduated cylinder having a movable piston. As a syringeneedle has appreciable volume, H2S can escape by diffusionfrom the needle tip. Therefore, a smooth fast work routine mustbe established to prevent delays and loss of sample.11.2 CalibrationTo pre
48、pare 1000 ppb/v sample add 10 Lof H2S to make a 10-L sample carrier mixture using the 10-Lacrylic cylinder described in 7.3.1. To calculate microlitres ofH2S required in a 10-L mixture, use the following equation:p 5 ppb/v 31022(1)where: p = microlitres of pollutant used. Prepare a referencestandard
49、 of a concentration slightly higher than may beanticipated in the sample. Purge the 10-L cylinder withH2S-free carrier gas. Purge the microlitre syringe with H2S.Gradually fill the 10-L cylinder with carrier gas as the syringeis adjusted for the proper quantity of H2S. Insert the syringequickly into the cylinder septum and inject the aliquot of H2Sinto the flowing carrier gas. Turn off the carrier gas when 10 Lare obtained. Withdraw the syringe quickly after injection toprevent residual H2S in the needle tip from diffusing into theflowing gas. The reference
