ASTM_D_4810_-_06_2015.pdf

Designation:D481006(Reapproved 2015)Standard Test Method forHydrogen Sulfide in Natural Gas Using Length-of-StainDetector Tubes1This standard is issued under the fixed designation D4810;the number immediately following the designation indicates the year oforiginal adoption or,in the case of 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 method covers a procedure for a rapid andsimple field determination of hydrogen sulfide in natural gaspipelines.Available detector tubes provide a total measuringrange of 0.5 ppm by volume up to 40%by volume,althoughthe majority of applications will be on the lower end of thisrange(that is,under 120 ppm).1.2 Typically,sulfur dioxide and mercaptans may causepositive interferences.In some cases,nitrogen dioxide cancause a negative interference.Most detector tubes will have a“precleanse”layer designed to remove certain interferences upto some maximum interferent level.Consult manufacturersinstructions for specific interference information.1.3 The values stated in SI units are to be regarded as thestandard.1.4 This standard does not 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 and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 Gas Processors Association Standard:No.2377-86 Test for Hydrogen Sulfide in Natural Gas UsingLength of Stain Tubes23.Summary of Test Method3.1 The sample is drawn through a detector tube filled witha specially prepared chemical.Any hydrogen sulfide present inthe sampling reacts with the chemical to produce a colorchange or stain.The length of the stain produced in the detectortube,when exposed to a measured volume of sample,isdirectly proportional to the amount of hydrogen sulfide presentin the sample.A hand-operated piston or bellows-type pump isused to draw a measured volume of sample through the tube ata controlled rate of flow.The length of stain produced isconverted to ppm(by volume)hydrogen sulfide(H2S),bycomparison to a calibration scale supplied by the manufacturerfor each box of detection tubes(higher range tubes have unitsof percent by volume).The system is direct reading,easilyportable,and completely suited to making rapid spot checks forhydrogen sulfide under field conditions.4.Significance and Use4.1 The measurement of hydrogen sulfide in natural gas isimportant because of the gas quality specifications,the corro-sive nature of H2S on pipeline materials,and the effects of H2Son utilization equipment.4.2 This test method provides inexpensive field screening ofhydrogen sulfide.The system design is such that it may be usedby nontechnical personnel with a minimum of proper training.5.Apparatus5.1 Length-of-StainDetectorTubeandCalibrationScaleA sealed glass tube with breakoff tips sized to fit thetube holder of the pump.The reagent layer inside the tube,typically a silica gel substrate coated with the active chemicals,must be specific for hydrogen sulfide and must produce adistinct color change when exposed to a sample of gascontaining hydrogen sulfide.Any substances known to inter-fere must be listed in the instructions accompanying the tubes.A calibration scale should be marked directly on the tube orother markings which provide for easy interpretation of hydro-gen sulfide content from a separate calibration scale suppliedwith the tubes.The calibration scale shall correlate hydrogensulfide concentration to the length of the color stain.Shelf lifeof the detector tubes must be a minimum of two years fromdate of manufacture when stored according to manufacturersrecommendations.1This test method is under the jurisdiction ofASTM Committee D03 on GaseousFuels and is the direct responsibility of Subcommittee D03.07 on Analysis ofChemical Composition of Gaseous Fuels.Current edition approved Nov.1,2015.Published December 2015.Originallyapproved in 1988.Last previous edition approved in 2011 as D4810-06(2011).DOI:10.1520/D4810-06R15.2Available from Gas Processors Association,1812 First National Bank Bldg.,Tulsa,OK 74103.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.2 Detector Tube PumpA hand-operated pump of apiston or bellows type.It must be capable of drawing 100 cm3per stroke of sample through the detector tube with a volumetolerance of 65 cm3.3It must be specifically designed for usewith detector tubes.NOTE1A detector tube and pump together form a unit and must beused as such.Each manufacturer calibrates detector tubes to match theflow characteristics of their specific pump.Crossing brands of pumps andtubes is not permitted,as considerable loss of system accuracy is likely tooccur.3(Note that at least one manufacturer allows extended samples upto