1、Designation: D2420 12D2420 12aStandard 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
2、, 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. Scope*1.1 This test method2 covers the detection of hydrogen sulfide in liquefied petroleum (LP) gases. The sensi
3、tivity of the test isabout 4 mg/m3 (0.15 to 0.2 grain of hydrogen sulfide per 100 ft3) of gas.1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.1.3 This standard does not purport to address all of the safety concerns, if any, a
4、ssociated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:3D1193 Specification for Reagent WaterD1265 Practice for S
5、ampling Liquefied Petroleum (LP) Gases, Manual MethodD1835 Specification for Liquefied Petroleum (LP) Gases2.2 GPA Standard:4GPA 2140 Liquefied Petroleum Gas Specifications and Test Methods3. Summary of Test Method3.1 The vaporizedVaporized LPgas is passed over moist lead acetate paper under control
6、led conditions. Hydrogen sulfide reactswith lead acetate to form lead sulfide which produces a coloration on the paper varying from yellow to black, depending upon theamount of hydrogen sulfide present.4. Significance and Use4.1 Liquefied petroleum gases and their products of combustion must not be
7、unduly corrosive to the materials with which theycome in contact. The potential personnel exposure hazards of H2S also make the detection and measurement of hydrogen sulfideimportant, even in low concentrations. In addition, in some cases the odor of the gases mustshall not be objectionable. (SeeSpe
8、cification D1835 and GPA 2140.)5. Interferences5.1 Methyl mercaptan, if present, produces a transitory yellow stain on the lead acetate paper that will fade completely in lessthan 5 min.5.2 Other sulfur compounds present in liquefied petroleum gas do not interfere with the test.1 This test method is
9、 under the jurisdiction of ASTM Committee D02 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.H0 onLiquefied Petroleum Gas.Current edition approved Aug. 15, 2012Nov. 1, 2012. Published November 2012February 2013. Originally approved in 1965. Last previous ed
10、ition approved in 20072012as D242007.12. DOI: 10.1520/D2420-12.10.1520/D2420-12A.2 This test method is based on Edwards, J. D., and McBride, R. S., “Lead Acetate Test for Hydrogen Sulphide in Gas,” Technologic Papers T41, National Institute forStandards and Technology, Aug. 9, 1914.3 For referencedA
11、STM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.4 Available from Gas Processors Association (GPA), 6526 E. 60th St., Tulsa, OK
12、 74145.74145, www.gpaglobal.org.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recomme
13、nds that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700,
14、 West Conshohocken, PA 19428-2959. United States16. Apparatus and Materials6.1 Apparatus for Detecting Hydrogen Sulfide in Liquefied Petroleum Gas, as shown in Fig. 1 or commercially availableapparatus.6.2 Lead Acetate Test PaperCommercially available test paper is satisfactory. Alternatively, the t
15、est paper may be preparedby dipping strips of smooth filter paper in 5 % aqueous lead acetate solution and removing the excess solution with a clean blotter.The strips of paper shall be approximately 50 mm long and 10 mm wide and contain a 3 mm hole near one end so they will hangfreely vertical in t
16、he test apparatus.6.3 Gas Flow IndicatorA wet test meter or a rotameter, which measures Capable of measuring flow rates in the range of 2to 3 L of gas/min.gas per minute. A wet test meter rotameter and mass flow controller have been found to be suitable.6.4 WaterDistilled.Unless otherwise indicated,
17、 reference to water shall be understood to mean reagent water that meets therequirements of Type II or III of Specification D1193, or better.6.5 TubingHigh pressure Highpressure connecting tubing to connect the test apparatus to the sample collection point.Internally clean, non-reactive and non-abso
18、rptive stainless steel material is recommended, but other materials that safely containthe pressure, resist being cut or torn, and have been tested to be inert relative to the stream being tested may be utilized.NOTE 1Internal surfaces of sample containers and associated lines and fitting may be sur
19、face coated to reduce bare metal surface reacting with tracehydrogen sulfide.56.5.1 Internal surfaces of sample containers, lines and fittings may be surface coated with an inert material to reduce bare metalsurfaces which could react with, or absorb, trace hydrogen sulfide.56.6 HighPressure Sample
20、Container, optionalDesigned for containing liquefied petroleum gas. An inert surface coating onthe inner surface of the container may be used, and is recommended.7. Sampling7.1 Collect a representative sample by Practice D1265 using a clean, highpressure sample container which is inert to hydrogensu
21、lfide.5 Internal surface coatings and coated cylinders are available commercially.FIG. 1 Typical Apparatus for Detecting Hydrogen Sulfide in Liquefied Petroleum GasD2420 12a27.1.1 As an alternative sampling procedure, connect the test apparatus directly to the sample source and perform the test in t
22、hefield. This method of direct field measurement eliminates any inaccuracy introduced by the sampling procedure or samplecontainer.7.2 (WarningBecause of Experience has demonstrated that the chemical activity and physical adsorptiveabsorptiveproperties of hydrogen sulfide, it is highly desirable to
23、connect the test apparatus directlysulfide can cause the concentration of H2to the sample source and perform the test in the field, rather than transferring sample into a sample cylinder for testing in thelaboratory. Experience has demonstrated that the hydrogen sulfide concentration in S in a lique
24、fied petroleum gas is frequentlysample to be depleted before analysis, even when the sample is contained in scrupulously clean, stainless steel sample cylinders.The exact opposite condition, Conversely, an increase in sulfide concentration,concentration has been found to occur when samplesof liquefi
25、ed petroleum gas containing no hydrogen sulfide are transferred intoin sample cylinders that have not been properlycleaned and which have been in use with samples containing hydrogen sulfide. This demonstrates that data obtained on samplestested for hydrogen sulfide in the laboratory can be unreliab
26、le.)might not reliably represent the hydrogen sulfide concentration atthe sample source.)8. Procedure8.1 Connect the test apparatus to the sample source by use of a minimum length of clean, non-reactive and non-absorptivestainless steel tubing orhighpressure tubing (see 6.5other material that safely
27、 contains the pressure, resists being cut or torn, andhas been tested to be inert 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 to 2.3 6 0.2 L
28、/min.8.5 Immediately, place a single strip of distilled water-moistened lead acetate paper on the hook in the test cylinder so that thepaper is held midway between the watchglass and the bottom of the upper stopper.8.6 Expose the moist paper for exactly 2 min to the gas flow of 2.360.2 L/min. Remove
29、 the test paper and proceed as describedin Section 910.9. Interpretation of Results9.1 Compare the exposed test paper with a moist test paper that has not been exposed.9.1.1 In the absence of distinct coloration, interpret the result as “negative” (“pass”).9.1.2 If there is a distinct coloration, wa
30、it 5 min before interpreting 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 in liquefied petroleum gas gives a distinct yellow stain to the test paper which, however, fades completelyi
31、n less than 5 min.9.1.2.2 If, after 5 min, the paper does have a distinct coloration, interpret the result as “positive” (“fail”).NOTE 2 Concentrations of H2S in LPG of 4 mg/m3 and higher will give a positive result.10. Report9.1 Compare the exposed test paper with a moist test paper that has not be
32、en exposed.9.1.1 In the absence of distinct coloration, report hydrogen sulfide as “negative” (“pass”).9.1.2 If there is a distinct coloration, wait 5 min before interpreting the test results. If, after 5 min, the paper has no distinctcoloration, rate the sample as “negative” (“pass”). If the paper
33、does have a distinct coloration after 5 min, rate the sample as“positive” (“fail”).NOTE 2The presence of methyl mercaptan in liquefied petroleum gas gives a distinct yellow stain to the test paper which, however, fades completelyin less than 5 min.NOTE 3 Concentrations of H2S in LPG of 4 mg/m3 and h
34、igher will give a positive result.10.1 Report the result, with reference to this test method, as either “negative” (“pass”) or “positive” (“fail”).11. Precision and Bias11.1 In the case of passfail data or results from other qualitative tests no generally accepted method for determining precisionor
35、bias is currently available.11.2 BiasThe procedure in Test Method D2420 for measuring hydrogen sulfide has no bias because the value of hydrogensulfide is defined only in terms of this test method.12. Keywords12.1 hydrogen sulfide; lead acetate; liquefied petroleum (LP) gasesD2420 12a3SUMMARY OF CHA
36、NGESSubcommittee D02.H0 has identified the location of selected changes to this standard since the last issue(D242007)12) that may impact the use of this standard.(1) Revised 6.3, 6.4, Section 7, 8.1, Section 9, and Fig. 1.(2) Revised Added Specification D1193 and Practice D1265 to Referenced Docume
37、nts, Section 6.510, 6.5.1, and 8.16.6.(3) AddedReorganized Note 19.1.2 to create 9.1.2.1 and 9.1.2.2renumbered 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 standard. Users o
38、f 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 reviewed every fiv
39、e 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 theresponsible technical co
40、mmittee, 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 Conshohocken, PA
41、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 12a4
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