ASTM_D_7833_-_14.pdf

Designation:D783314Standard Test Method forDetermination of Hydrocarbons and Non-HydrocarbonGases in Gaseous Mixtures by Gas Chromatography1This standard is issued under the fixed designation D7833;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 is intended to quantitatively determinethe non-condensed hydrocarbon gases with carbon numbersfrom C1to C5+and non-hydrocarbon gases,such as H2,CO2,O2,N2,and CO,in gaseous samples.This test method is acompanion standard test method to Test Method D1945 andPractice D1946 differing in that it incorporates use of capillarycolumns instead of packed columns and allows other techno-logical differences.1.2 Hydrogen sulfide can be detected but may not beaccurately determined by this procedure due to loss in samplecontainers or sample lines and possible reactions unless specialprecautions are taken.1.3 Non-hydrocarbon gases have a lower detection limit inthe concentration range of 0.03 to 100 mole percent using athermal conductivity detector(TCD)and C1to C6hydrocar-bons have a lower detection limit in the range of 0.005 to 100mole percent using a flame ionization detector(FID);using aTCD may increase the lower detection limit to approximately0.03 mole percent.1.3.1 Hydrocarbon detection limits can be reduced with theuse of pre-concentration techniques and/or cryogenic trapping.1.4 This test method does not fully determine individualhydrocarbons heavier than benzene,which are grouped to-gether as C7+When detailed analysis is not required thecompounds with carbon number greater than C5may begrouped as either C6+,or C7+.Accurate analysis of C5+components depends on proper vaporization of these com-pounds during sampling at process unit sources as well as inthe sample introduction into the analyzer in the laboratory.1.5 Water vapor may interfere with the C6+analysis if aTCD detector is used.1.6 Helium and argon may interfere with the determinationof hydrogen and oxygen respectively.Depending on theanalyzer used,pentenes,if present,may either be separated orgrouped with the C6+components.1.7 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.8 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 ASTM Standards:2D1945 Test Method for Analysis of Natural Gas by GasChromatographyD1946 Practice for Analysis of Reformed Gas by GasChromatographyD3588 Practice for Calculating Heat Value,CompressibilityFactor,and Relative Density of Gaseous FuelsE355 Practice for Gas Chromatography Terms and Relation-shipsE1510 Practice for Installing Fused Silica Open TubularCapillary Columns in Gas ChromatographsF307 Practice for Sampling Pressurized Gas for Gas Analy-sis2.2 ASTM Publication:ASTM DS 4B,1991 Physical Constants of Hydrocarbon andNon-Hydrocarbon Compounds3.Terminology3.1 Terminology related to the practice of gas chromatog-raphy can be found in Practice E355.3.2 Definitions:3.2.1 sample seta collection of samples taken from thesame source or at similar component composition and concen-trations.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 June 1,2014.Published June 2014.Originallyapproved in 2012.Last previous edition approved in 2012 as D7833-12.DOI:10.1520/D7833-14.2For 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 4.Summary of Test Method4.1 Components in a representative sample are physicallyseparated by gas chromatography(GC)and compared tocalibration data obtained under identical operating conditionsfrom a reference standard mixture of known composition.Thenumerous heavy-end components of a sample can be groupedinto irregular peaks by reversing the direction of the carrier gasthrough the column at such time as to group the heavy endseither as C5and heavier,C6and heavier,or C7and heavier oralternatively elute them in the non-backflushed mode andsummed accordingly.The composition of the sample is calcu-lated by comparing the peak areas with the correspondingvalues obtained with the reference standard.5.Significance and Use5.1 The hydrocarbon componen