ASTM_D_1946_-_90_2015e1.pdf

Designation:D194690(Reapproved 2015)1Standard Practice forAnalysis of Reformed Gas by Gas Chromatography1This standard is issued under the fixed designation D1946;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.1NOTESection 5 updated editorially in December 2015.1.Scope1.1 This practice covers the determination of the chemicalcomposition of reformed gases and similar gaseous mixturescontaining the following components:hydrogen,oxygen,nitrogen,carbon monoxide,carbon dioxide,methane,ethane,and ethylene.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 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:2E260 Practice for Packed Column Gas Chromatography3.Summary of Practice3.1 Components in a sample of reformed gas are physicallyseparated by gas chromatography and compared to correspond-ing components of a reference standard separated underidentical operating conditions,using a reference standardmixture of known composition.The composition of the re-formed gas is calculated by comparison of either the peakheight or area response of each component with the corre-sponding value of that component in the reference standard.4.Significance and Use4.1 The information about the chemical composition can beused to calculate physical properties of the gas,such as heating(calorific)valueandrelativedensity.Combustioncharacteristics,products of combustion,toxicity,and inter-changeability with other fuel gases may also be inferred fromthe chemical composition.5.Apparatus5.1 DetectorThe detector shall be a thermal conductivitytype or its equivalent in stability and sensitivity.The thermalconductivity detector must be sufficiently sensitive to producea signal of at least 0.5 mV for 1 mol%methane in a 0.5-mLsample.5.2 Recording InstrumentsEither strip chart recorders orelectronic integrators,or both,are used to display the separatedcomponents.It is highly desirable to evaluate the performanceof strip chart recorders or electronic integrators.5.2.1 The recorder,when used,shall be a strip chart recorderwith a full-range scale of 5 mV or less(1 mV preferred).Thewidth of the chart shall be not less than 150 mm.A maximumpen response time of 2 s(1 s preferred)and a minimum chartspeed of 10 mm/min shall be required.Faster speeds up to 100mm/min are desirable if the chromatogram is to be interpretedusing manual methods to obtain areas.5.2.2 Electronic or Computing IntegratorsProof of sepa-ration and response equivalent to that for the recorder isrequired for displays other than by chart recorder.5.3 AttenuatorIf manual methods are used to interpret thechromatogram,an attenuator must be used with the detectoroutput signal to keep the peak maxima within the range of therecorder chart.The attenuator must be accurate to within 0.5%between the attenuator range steps.5.4 Sample Inlet System:5.4.1 The sample inlet system must be constructed ofmaterials that are inert and nonadsorptive with respect to thecomponents in the sample.The preferred material of construc-tion is stainless steel.Copper and copper-bearing alloys areunacceptable.5.4.2 Provision must be made to introduce into the carriergas ahead of the analyzing column a gas-phase sample that hasbeen entrapped in either a fixed volume loop or tubular section.The injected volume must be reproducible such that successive1This practice is under the jurisdiction of ASTM 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 1962.Last previous edition approved in 2011 as D1946 90(2011).DOI:10.1520/D1946-90R15.2For 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 runs of the same sample agree within the limits of repeatabilityfor the concentration range as specified in 11.1.1.5.4.3 If the instrument is calibrated with pure components,the inlet system shall be equipped to introduce a sample at lessthan atmospheric pressure.The pressure-sensing device mustbe accurate to 0.1 kPa(1 mm Hg).5.5 Column Temperature Control:5.5.1 IsothermalWhen isothermal operation is used,thea