ASTM D2420-2013(2018) Standard Test Method for Hydrogen Sulfide in Liquefied Petroleum (LP) Gases (Lead Acetate Method).pdf

1、Designation: D2420 13 (Reapproved 2018)Standard 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

2、 revision, the year 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. Scope1.1 This test method2covers the detection of hydrogensulfide in liquefied petroleum (LP) gases. The

3、 sensitivity of thetest 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 after SI units areprovided for information only and are not considered standard.1.3 This standard does no

4、t purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.4 This international s

5、tandard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2

6、. Referenced Documents2.1 ASTM Standards:3D1193 Specification for Reagent WaterD1265 Practice for Sampling Liquefied Petroleum (LP)Gases, Manual MethodD1835 Specification for Liquefied Petroleum (LP) Gases2.2 GPA Standard:4GPA 2140 Liquefied Petroleum Gas Specifications and TestMethods3. Summary of

7、Test Method3.1 Vaporized LPgas is passed over moist lead acetate paperunder controlled conditions. Hydrogen sulfide 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

8、and Use4.1 Liquefied petroleum gases and their products of com-bustion must not be unduly corrosive to the materials withwhich they come in contact. The potential personnel exposurehazards of H2S also make the detection and measurement ofhydrogen sulfide important, even in low concentrations. Inaddi

9、tion, in some cases the odor of the gases shall not beobjectionable. (See Specification D1835 and GPA 2140.)5. Interferences5.1 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

10、liquefied petroleumgas do not interfere with the test.6. Apparatus and Materials6.1 Apparatus for Detecting Hydrogen Sulfide in LiquefiedPetroleum Gas, as shown in Fig. 1 or commercially availableapparatus.6.2 Lead Acetate Test PaperCommercially available testpaper is satisfactory. Alternatively, th

11、e test paper may beprepared by dipping strips of smooth filter paper in 5 %aqueous lead acetate solution and removing the excess solutionwith a clean blotter. The strips of paper shall be approximately50 mm long and 10 mm wide and contain a 3 mm hole nearone end so they will hang freely vertical in

12、the test apparatus.6.3 Gas Flow IndicatorCapable of measuring flow ratesin the range of 2 L to 3 L of gas per minute. 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

13、 meets therequirements of Type II or III of Specification D1193,ordistilled water.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.H0 on Liquefied Petroleum Gas.Current edition app

14、roved April 1, 2018. Published June 2018. Originallyapproved in 1965. Last previous edition approved in 2013 as D2420 13. DOI:10.1520/D2420-13R18.2This test method is based on Edwards, J. D., and McBride, R. S., “LeadAcetateTest for Hydrogen Sulphide in Gas,” Technologic Papers T41, National Institu

15、te 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 page onthe ASTM website.4Available from

16、Gas Processors Association (GPA), 66 American Plaza, Suite700, Tulsa, OK 74135, http:/www.gpaglobal.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recogn

17、ized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.16.5 TubingHigh-pressure connecting tubing to connect thetest appa

18、ratus to the sample collection point. Internally clean,non-reactive and non-absorptive stainless steel material isrecommended, 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 Inte

19、rnal surfaces of sample containers, lines and fit-tings may be surface coated with an inert material to reducebare metal surfaces which could react with, or absorb, tracehydrogen sulfide.56.6 HighPressure Sample Container, optionalDesignedfor containing liquefied petroleum gas.An inert surface coati

20、ngon the inner surface of the container may be used, and isrecommended.7. Sampling7.1 Collect a representative 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

21、sample source and perform the test inthe field. This method of direct field measurement eliminatesany inaccuracy 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

22、 the concentration of H2S in a liquefiedpetroleum gas sample to be depleted before analysis, evenwhen the sample is contained in scrupulously clean, stainlesssteel sample cylinders. Conversely, an increase in sulfideconcentration has been found to occur when samples ofliquefied petroleum gas contain

23、ing no hydrogen sulfide aretransferred in sample cylinders that have not been properlycleaned and which have 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 sulf

24、ide concentration at thesample source.)8. Procedure8.1 Connect the test apparatus to the sample source by useof a minimum length of high-pressure 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

25、use of the needle valve, adjust the rate of gas flow to2.3 L min 6 0.2 L min.8.5 Immediately, place a single strip 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 pape

26、r for exactly 2 min to the gas flowof 2.3 L min 6 0.2 L min. Remove the test paper and proceedas described in Section 10.9. 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 comme

27、rcially.FIG. 1 Typical Apparatus for Detecting Hydrogen Sulfide in Liquefied Petroleum GasD2420 13 (2018)29.1.1 In the absence 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

28、5 min, the paper has no distinct coloration,interpret the result as “negative” (“pass”).NOTE 1The presence of methyl mercaptan 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 d

29、istinctcoloration, interpret the result as “positive” (“fail”).NOTE 2 Concentrations of H2S in LPG of 4 mg m3and higher willgive 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 t

30、he case of pass-fail data or results from otherqualitative tests no generally accepted method for determiningprecision or bias 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

31、of this test method.12. Keywords12.1 hydrogen sulfide; lead acetate; liquefied petroleum(LP) gasesASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determ

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34、your comments have not received 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 (s

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