1、Designation: D2420 12Standard 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:3D1835 Specification for Liquefied Petroleum (LP) Gases2.2 GPA Standard
5、:4GPA 2140 Liquefied Petroleum Gas Specifications and TestMethods3. Summary of Test Method3.1 The vaporized LP gas is passed over moist lead acetatepaper under controlled conditions. Hydrogen sulfide reactswith lead acetate to form lead sulfide which produces acoloration on the paper varying from ye
6、llow to black, depend-ing upon the amount 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 materials withwhich they come in contact. The potential personnel exposurehazards of H2S also make the dete
7、ction and measurement ofhydrogen sulfide important, even in low concentrations. Inaddition, in some cases the odor of the gases must not beobjectionable. (See Specification D1835 and GPA 2140.)5. Interferences5.1 Methyl mercaptan, if present, produces a transitoryyellow stain on the lead acetate pap
8、er 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 Hydrogen Sulfide in LiquefiedPetroleum Gas, as shown in Fig. 1 or commercially availableapparatus.6.2 Lead
9、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 removing the excess solutionwith a clean blotter. The strips of paper shall be approximately50 mm long and
10、 10 mm wide and containa3mmhole near oneend so they will hang freely vertical in the test apparatus.6.3 Flow IndicatorA wet test meter or a rotameter, whichmeasures flow rates in the range of 2 to 3 L of gas/min.6.4 WaterDistilled.6.5 TubingHigh pressure connecting tubing to connect thetest apparatu
11、s to the sample collection point. Internally clean,non-reactive and non-absorptive stainless steel material isrecommended, but other materials that safely contain the1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricantsand is the direct responsibility
12、of SubcommitteeD02.H0 on Liquefied Petroleum Gas.Current edition approved Aug. 15, 2012. Published November 2012. Originallyapproved in 1965. Last previous edition approved in 2007 as D242007. DOI:10.1520/D2420-12.2This test method is based on Edwards, J. D., and McBride, R. S., “LeadAcetateTest for
13、 Hydrogen Sulphide in Gas,” 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
14、 standards Document Summary page onthe ASTM website.4Available from Gas Processors Association (GPA), 6526 E. 60th St., Tulsa, OK74145.*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.
15、United States1pressure, resist being cut or torn, and have been tested to beinert relative to the stream being tested may be utilized.NOTE 1Internal surfaces of sample containers and associated linesand fitting may be surface coated to reduce bare metal surface reactingwith trace hydrogen sulfide.57
16、. Sampling7.1 (WarningBecause of the chemical activity and physi-cal adsorptive properties of hydrogen sulfide, it is highlydesirable to connect the test apparatus directly to the samplesource and perform the test in the field, rather than transferringsample into a sample cylinder for testing in the
17、 laboratory.Experience has demonstrated that the hydrogen sulfide concen-tration in liquefied petroleum gas is frequently depleted beforeanalysis, even when the sample is contained in scrupulouslyclean, stainless steel sample cylinders. The exact oppositecondition, an increase in sulfide concentrati
18、on, has been foundto occur when samples of liquefied petroleum gas containingno hydrogen sulfide are transferred into sample cylinders thathave not been properly cleaned and which have been in usewith samples containing hydrogen sulfide. This demonstratesthat data obtained on samples tested for hydr
19、ogen sulfide in thelaboratory can be unreliable.)8. Procedure8.1 Connect the test apparatus to the sample source by useof a minimum length of clean, non-reactive and non-absorptivestainless steel tubing or other material that safely contains thepressure, resists being cut or torn, and has been teste
20、d to beinert relative to the stream being tested.8.2 Flush the line and apparatus for about 1 min.8.3 Fill the water reservoir with warm water (50 to 70C).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 strip of distilled water-moistened
21、lead acetate paper on the hook in the test cylinder sothat the paper is held midway between the watchglass and thebottom of 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 9.9. Report9.1 Compar
22、e the exposed test paper with a moist test paperthat has not been exposed.9.1.1 In the absence of distinct coloration, report hydrogensulfide as “negative” (“pass”).9.1.2 If there is a distinct coloration, wait 5 min beforeinterpreting the test results. If, after 5 min, the paper has nodistinct colo
23、ration, rate the sample as “negative” (“pass”). Ifthe paper does have a distinct coloration after 5 min, rate thesample as “positive” (“fail”).NOTE 2The presence of methyl mercaptan in liquefied petroleum gasgives a distinct yellow stain to the test paper which, however, fadescompletely in less than
24、 5 min.NOTE 3 Concentrations of H2S in LPG of 4 mg/m3and higher willgive a positive result.5Internal surface coatings and coated cylinders are available commercially.FIG. 1 Apparatus for Detecting Hydrogen Sulfide in Liquefied Petroleum GasD2420 1229.2 Report the result, with reference to this test
25、method, aseither “negative” (“pass”) or “positive” (“fail”).10. Precision and Bias10.1 In the case of passfail data or results from otherqualitative tests no generally accepted method for determiningprecision or bias is currently available.10.2 BiasThe procedure in Test Method D2420 for mea-suring h
26、ydrogen sulfide has no bias because the value ofhydrogen sulfide is defined only in terms of this test method.11. Keywords11.1 hydrogen sulfide; liquefied petroleum (LP) gasesSUMMARY OF CHANGESSubcommittee D02.H0 has identified the location of selected changes to this standard since the last issue(D
27、242007) that may impact the use of this standard.(1) Revised Fig. 1.(2) Revised 6.5 and 8.1.(3) Added Note 1 and renumbered remaining notes.(4) Added Footnote 5.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this sta
28、ndard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be revi
29、ewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsib
30、le technical committee, which you may attend. If you feel that 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 Co
31、nshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D2420 123
