ASTM_D_2505_-_88_2015.pdf

Designation:D250588(Reapproved 2015)Standard Test Method forEthylene,Other Hydrocarbons,and Carbon Dioxide in High-Purity Ethylene by Gas Chromatography1This standard is issued under the fixed designation D2505;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 the determination of carbondioxide,methane,ethane,acetylene,and other hydrocarbons inhigh-purity ethylene.Hydrogen,nitrogen,oxygen,and carbonmonoxide are determined in accordance with Test MethodD2504.The percent ethylene is obtained by subtracting thesum of the percentages of the hydrocarbon and nonhydrocar-bon impurities from 100.The method is applicable over therange of impurities from 1 to 500 parts per million volume(ppmV).1.2This 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.For some specifichazard statements,see Section 6.1.3 The values stated in SI units are to be regarded as thestandard.The values in parentheses are for information only.2.Referenced Documents2.1 ASTM Standards:2D2504 Test Method for Noncondensable Gases in C2andLighter Hydrocarbon Products by Gas ChromatographyD4051 Practice for Preparation of Low-Pressure Gas BlendsE260 Practice for Packed Column Gas ChromatographyF307 Practice for Sampling Pressurized Gas for Gas Analy-sis3.Summary of Test Method3.1 The sample is separated in a gas chromatograph systemutilizing four different packed chromatographic columns withhelium as the carrier gas.Methane and ethane are determinedby using a silica gel column.Propylene and heavier hydrocar-bons are determined using a hexamethylphosphoramide(HMPA)column.Acetylene is determined by using,in series,a hexadecane column and a squalane column.Carbon dioxideis determined using a column packed with activated charcoalimpregnated with a solution of silver nitrate in,-oxydipropionitrile.Columns other than those mentioned abovemay be satisfactory(see 5.3).Calibration data are obtainedusing standard samples containing the impurities,carbondioxide,methane,and ethane in the range expected to beencountered.Calibration data for acetylene are obtained as-suming that acetylene has the same peak area response on aweight basis as methane.The acetylene content in a sample iscalculated on the basis of the ratio of peak area of the acetylenepeak to the peak area of a known amount of methane.Calculations for carbon dioxide,methane,and ethane arecarried out by the peak-height measurement method.4.Significance and Use4.1 High-purity ethylene is required as a feedstock for somemanufacturing processes,and the presence of trace amounts ofcarbon dioxide and some hydrocarbons can have deleteriouseffects.This method is suitable for setting specifications,foruse as an internal quality control tool and for use in develop-ment or research work.5.Apparatus5.1 Any chromatographic instrument with an overall sensi-tivity sufficient to detect 2 ppmV or less of the compoundslisted with a peak height of at least 2 mm without loss ofresolution.5.2 DetectorsThermal ConductivityIf a methanation re-actor is used,a flame ionization detector is also required.Todetermine carbon dioxide with a flame ionization detector,amethanation reactor must be inserted between the column andthe detector and hydrogen added as a reduction gas(see TestMethod D2504,Appendix X1,Preparation of MethanationReactor).1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricantsand is the direct responsibility ofSubcommittee D02.D0.02 on Ethylene.Current edition approved June 1,2015.Published July 2015.Originally approvedin 1966.Last previous edition approved in 2010 as D2505 88(2010).DOI:10.1520/D2505-88R15.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.3 ColumnAny column or set of columns can be usedthat separates carbon dioxide,methane,acetylene and C3andheavier compounds.There may be tailing of the ethylene peakbut do not use any condition such that the depth of the valleysahead of the trace peak is less than 50%of the trace peakheight.(See Fig.1 for example.)5.4 RecorderA recorder with a full-scale response of 2 sor less and a maximum rate of noise of 60.3%of full scale.5.5 Gas-Blending ApparatusA typical gas-blending appa-ratus is shown in Fig.2.A high-pressure man