1、Designation: D2420 13Standard Test Method forHydrogen Sulfide in Liquefied Petroleum (LP) Gases (LeadAcetate Method)1This standard is issued under the fixed designation D2420; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the yea
2、r of 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. Scope*1.1 This test method2covers the detection of hydrogensulfide in liquefied petroleum (LP) gases. The sensitivity of t
3、hetest is about 4 mg/m3(0.15 to 0.2 grain of hydrogen sulfide per100 ft3) of gas.1.2 The values stated in SI units are to be regarded asstandard. The values given in parentheses are for informationonly.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with i
4、ts use. It is theresponsibility 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.2. Referenced Documents2.1 ASTM Standards:3D1193 Specification for Reagent WaterD1265 Practice for Sampling Lique
5、fied Petroleum (LP)Gases, Manual MethodD1835 Specification for Liquefied Petroleum (LP) Gases2.2 GPA Standard:4GPA 2140 Liquefied Petroleum Gas Specifications and TestMethods3. Summary of Test Method3.1 Vaporized LPgas is passed over moist lead acetate paperunder controlled conditions. Hydrogen sulf
6、ide reacts with leadacetate to form lead sulfide which produces a coloration on thepaper varying from yellow to black, depending upon theamount of hydrogen sulfide present.4. Significance and Use4.1 Liquefied petroleum gases and their products of com-bustion must not be unduly corrosive to the mater
7、ials withwhich they come in contact. The potential personnel exposurehazards of H2S also make the detection and measurement ofhydrogen sulfide important, even in low concentrations. Inaddition, in some cases the odor of the gases shall not beobjectionable. (See Specification D1835 and GPA 2140.)5. I
8、nterferences5.1 Methyl mercaptan, if present, produces a transitoryyellow stain on the lead acetate paper that will fade completelyin less than 5 min.5.2 Other sulfur compounds present in liquefied petroleumgas do not interfere with the test.6. Apparatus and Materials6.1 Apparatus for Detecting Hydr
9、ogen Sulfide in LiquefiedPetroleum Gas, as shown in Fig. 1 or commercially availableapparatus.6.2 Lead Acetate Test PaperCommercially available testpaper is satisfactory. Alternatively, the test paper may beprepared by dipping strips of smooth filter paper in 5 %aqueous lead acetate solution and rem
10、oving the excess solutionwith a clean blotter. The strips of paper shall be approximately50 mm long and 10 mm wide and containa3mmhole near oneend so they will hang freely vertical in the test apparatus.6.3 Gas Flow IndicatorCapable of measuring flow ratesin the range of 2 to 3 L of gas per minute.
11、A wet test meterrotameter and mass flow controller have been found to besuitable.6.4 WaterUnless otherwise indicated, reference to watershall be understood to mean reagent water that meets therequirements of Type II or III of Specification D1193,ordistilled water.6.5 TubingHighpressure connecting tu
12、bing to connectthe test apparatus to the sample collection point. Internallyclean, non-reactive and non-absorptive stainless steel material1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.H0 on L
13、iquefied Petroleum Gas.Current edition approved June 15, 2013. Published July 2013. Originallyapproved in 1965. Last previous edition approved in 2012 as D2420 12a. DOI:10.1520/D2420-13.2This test method is based on Edwards, J. D., and McBride, R. S., “LeadAcetateTest for Hydrogen Sulphide in Gas,”
14、Technologic Papers T41, National Institute forStandards and Technology, Aug. 9, 1914.3For 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
15、page onthe ASTM website.4Available from Gas Processors Association (GPA), 6526 E. 60th St., Tulsa, OK74145, www.gpaglobal.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United St
16、ates1is recommended, but other materials that safely contain thepressure, resist being cut or torn, and have been tested to beinert relative to the stream being tested may be utilized.6.5.1 Internal surfaces of sample containers, lines and fit-tings may be surface coated with an inert material to re
17、ducebare metal surfaces which could react with, or absorb, tracehydrogen sulfide.56.6 HighPressure Sample Container, optionalDesignedfor containing liquefied petroleum gas.An inert surface coatingon the inner surface of the container may be used, and isrecommended.7. Sampling7.1 Collect a representa
18、tive sample by Practice D1265 usinga clean, highpressure sample container which is inert tohydrogen sulfide.7.1.1 As an alternative sampling procedure, connect the testapparatus directly to the sample source and perform the test inthe field. This method of direct field measurement eliminatesany inac
19、curacy introduced by the sampling procedure orsample container.7.2 (WarningExperience has demonstrated that thechemical activity and physical absorptive properties of hydro-gen sulfide can cause the concentration of H2S in a liquefiedpetroleum gas sample to be depleted before analysis, evenwhen the
20、sample is contained in scrupulously clean, stainlesssteel sample cylinders. Conversely, an increase in sulfideconcentration has been found to occur when samples ofliquefied petroleum gas containing no hydrogen sulfide aretransferred in sample cylinders that have not been properlycleaned and which ha
21、ve been in use with samples containinghydrogen sulfide. This demonstrates that data obtained onsamples tested for hydrogen sulfide in the laboratory might notreliably represent the hydrogen sulfide concentration at thesample source.)8. Procedure8.1 Connect the test apparatus to the sample source by
22、useof a minimum length of highpressure tubing (see 6.5).8.2 Flush the line and apparatus for about 1 min.8.3 Fill the water bath with warm water (50 C to 70 C).Tap water is satisfactory.8.4 By use of the needle valve, adjust the rate of gas flow to2.3 6 0.2 L/min.8.5 Immediately, place a single stri
23、p of water-moistenedlead acetate paper on the hook in the test cylinder so that thepaper is held midway between the watchglass and the bottomof the upper stopper.8.6 Expose the moist paper for exactly 2 min to the gas flowof 2.3 6 0.2 L/min. Remove the test paper and proceed asdescribed in Section 1
24、0.9. Interpretation of Results9.1 Compare the exposed test paper with a moist test paperthat has not been exposed.5Internal surface coatings and coated cylinders are available commercially.FIG. 1 Typical Apparatus for Detecting Hydrogen Sulfide in Liquefied Petroleum GasD2420 1329.1.1 In the absence
25、 of distinct coloration, interpret theresult as “negative” (“pass”).9.1.2 If there is a distinct coloration, wait 5 min beforeinterpreting the test results.9.1.2.1 If, after 5 min, the paper has no distinct coloration,interpret the result as “negative” (“pass”).NOTE 1The presence of methyl mercaptan
26、 in liquefied petroleum gasgives a distinct yellow stain to the test paper which, however, fadescompletely in less than 5 min.9.1.2.2 If, after 5 min, the paper does have a distinctcoloration, interpret the result as “positive” (“fail”).NOTE 2 Concentrations of H2S in LPG of 4 mg/m3and higher willgi
27、ve a positive result.10. Report10.1 Report the result, with reference to this test method, aseither “negative” (“pass”) or “positive” (“fail”).11. Precision and Bias11.1 In the case of passfail data or results from otherqualitative tests no generally accepted method for determiningprecision or bias
28、is currently available.11.2 BiasThe procedure in Test Method D2420 for mea-suring hydrogen sulfide has no bias because the value ofhydrogen sulfide is defined only in terms of this test method.12. Keywords12.1 hydrogen sulfide; lead acetate; liquefied petroleum(LP) gasesSUMMARY OF CHANGESSubcommitte
29、e D02.H0 has identified the location of selected changes to this standard since the last issue(D2420 12a) that may impact the use of this standard. (Approved June 15, 2013.)(1) Revised 6.4 to allow use of distilled water. (2) Revised 8.3 and 8.5 to clarify water requirements.Subcommittee D02.H0 has
30、identified the location of selected changes to this standard since the last issue(D2420 12) that may impact the use of this standard. (Approved Nov. 1, 2012.)(1) Revised 6.3, 6.4, Section 7, 8.1, Section 9, and Fig. 1.(2) Added Specification D1193 and Practice D1265 to Refer-enced Documents, Section
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34、eived a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies)
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