1、Designation: D7676 18Standard Practice forScreening Organic Halides Contained in Hydrogen or OtherGaseous Fuels1This standard is issued under the fixed designation D7676; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of
2、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 practice covers the screening of organic halidecontent of gaseous fuels using electron capture detection.Although
3、 primarily intended for determining organic halides inhydrogen used as a fuel for fuel cell or internal combustionengine powered vehicles, this screening method can also beused, if qualified, to measure organic halides in other gaseousfuels and gaseous matrices.1.2 The procedure described in this me
4、thod was designed toscreen organic halides in hydrogen to a level much less thanrequired by SAE J2719 and the California Code ofRegulations, Title 4, Division 9, Chapter 6, Article 8, Sections4180 4181. It will yield false positive result to othercompounds that show response to the ECD detector. Sam
5、plesthat do not pass the criteria of this screening process shall betested to quantify and qualify the contaminants using TestMethod D7892.1.3 The values stated in SI units are to be regarded asstandard. The values given in parentheses after SI units areprovided for information only and are not cons
6、idered standard.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, health, and environmental practices and deter-mine the applicability of regulatory limitati
7、ons prior to use.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization Tec
8、hnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D1265 Practice for Sampling Liquefied Petroleum (LP)Gases, Manual MethodD3700 Practice for Obtaining LPG Samples Using a Float-ing Piston CylinderD7606 Practice for Sampling of High Pressure Hydrogenand Related Fuel C
9、ell Feed GasesD7892 Test Method for Determination of Total OrganicHalides, Total Non-Methane Hydrocarbons, and Formal-dehyde in Hydrogen Fuel by Gas Chromatography/MassSpectrometry2.2 ISO Standard:3ISO TS 14687-2 Hydrogen Fuel Product Specification Part 2: Proton Exchange Membrane (PEM) Fuel CellApp
10、lications for Road Vehicles2.3 SAE Standard:4SAE J2719 Hydrogen Fuel Quality for Fuel Cell Vehicles2.4 Additional Document:5California Code of Regulations Title 4, Division 9, Chapter6, Article 8, Sections 4180 41813. Terminology3.1 Definitions:3.1.1 electron capture detector (ECD), ndetects organic
11、halides by the reduction of a standing detector current due tothe capture of detector current electrons by the halogenatedhydrocarbons.1This practice is under the jurisdiction of ASTM Committee D03 on GaseousFuels and is the direct responsibility of Subcommittee D03.14 on Hydrogen andFuel Cells.Curr
12、ent edition approved Dec. 15, 2018. Published February 2019. DOI:10.1520/D7676-18.2For 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 pag
13、e onthe ASTM website.3Available from International Organization for Standardization (ISO), ISOCentral Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier,Geneva, Switzerland, http:/www.iso.org.4Available from SAE International (SAE), 400 Commonwealth Dr., Warrendale,PA 15096, http:/ww
14、w.sae.org.5Available from California Department of Food and Agriculture, 1220 N Street,Sacramento, CA 95814, https:/www.cdfa.ca.gov.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance
15、 with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.13.1.2 fuel cell grade hydrogen, nhydr
16、ogen satisfying thespecifications in SAE J2719.3.1.3 organic halide, nany compound containing carbonand a halogen (fluorine, chlorine, bromine, or iodine).3.1.4 total organic halides, nthe sum concentration of allcompounds containing carbon and at least one halide (fluorine,chlorine, bromine, or iod
17、ine).4. Summary of Screening Method4.1 The screening of organic halides in hydrogen and othergaseous fuels can be challenging due to need to measure totalorganic halides to 0.05 mol mol (50 ppb) to satisfy hydrogenfuel contaminant requirements specified in ISO TS 14687-2,SAE J2719, and the Californi
18、a Code of Regulations.4.2 Organic halides, at any detectable concentration, are notnormally present in hydrogen. Any contamination observedwill be due to improper maintenance or cleaning of equipment;therefore, any positive result should be cause for further testingand evaluation.4.3 A gas chromatog
19、raph equipped with an ECD detectorand gas sampling system with a 1 mL sample loop is typicallyused. The GC column is replaced by a length of blank tubing.Carrier gas and detector flows are set to manufacturersspecifications.4.4 The sample gas is injected into the inlet of the GC-ECDsystem through th
20、e blank tubing and the ECD detector.Asignalis produced as organic halides pass though the detector. Thesignal is sent to a computer, integrator, or other recordingdevice.4.5 This standard is intended to provide a pass/fail test ofpresence of organic halides. Its use to rigorously quantifyorganic hal
21、ides in gaseous fuels has not been demonstrated.Some fuels may contain contaminates that would preclude theuse of this method.5. Significance and Use5.1 Low operating temperature fuel cells such as protonexchange membrane fuel cells (PEFCs) require high purityhydrogen for maximum material performanc
22、e and lifetime.Analysis to at least 0.05 mol mol concentration of totalhalogenated (measured as methyl fluoride) in hydrogen isnecessary for assuring a feed gas of sufficient purity to satisfyfuel cell system needs as defined in ISO TS 14687-2, SAEJ2719, and the California Code of Regulations, or as
23、 specifiedin regulatory codes.5.2 Although not intended for application to gases otherthan hydrogen, techniques within this screening method can beapplied to other gaseous samples requiring total halogenatedhydrocarbon content determination. The method must bevalidated when used to test fuels or oth
24、er gaseous samples thatmay contain interfering compounds.6. Interferences6.1 Other Electron Capturing Sensitive Compounds, mostnotably oxygen, water, and other oxygenated compounds.6.2 The electron capture detector is very sensitive, typicallycapable of measuring organic halides to 0.0001 mol mol.An
25、yinterfering contamination of carrier and detector gases witheither organic halides, oxygen, or water can render the ECDdetector either unusable or result in a positive bias. All supplyand dilution gases must be of the highest purity and in-linepurification may be required.6.3 All components in cont
26、act with the carrier, detector, andsample gases must be cleaned and free of halogen contamina-tion. Metal to metal seals shall be used whenever possible.Teflon seals shall be avoided.7. Apparatus7.1 The apparatus and analytic parameters below have beensuccessfully used to satisfy the measurement req
27、uirementsdescribed in this standard. Other parameters can be usedprovided measurement requirements and quality assuranceobjectives can be satisfied.7.1.1 Gas Chromatograph, with electron capture detectorand electronic signal integrator, computer, or other recordingdevice7.1.2 Gas Sampling System, wi
28、th 1 mL sample loop or othersample loop volume satisfying organic halide measurementneeds.8. Reagents and Materials8.1 Helium Carrier/makeup Gas with Minimum Specifica-tions: Oxygen 0.5 ppm, Water 0.2 ppm, Total Hydrocar-bons 0.1 ppm, Carbon Monoxide 0.1 ppm, Carbon Dioxide 0.1 ppm.8.2 Nitrogen Dete
29、ctor Gas with Minimum Specifications:Oxygen 1 ppm, Water 1 ppm, Total Hydrocarbons 0.5 ppm, Carbon Monoxide 0.5 ppm, Carbon Dioxide 0.5 ppm.8.3 Calibration Gas Standards, with 10 ppb, 50 ppb, and100 ppb (mol/mol) methyl fluoride (CAS 392-56-3) in hydro-gen (minimum hydrogen specifications Oxygen 0.5
30、 ppm,Water 0.5 ppm, Total Hydrocarbons 0.1 ppm, CarbonMonoxide 0.1 ppm, Carbon Dioxide 0.1 ppm).8.4 Hydrogen Zero Gas with Minimum Specifications: Oxy-gen 0.5 ppm, Water 0.5 ppm, Total Hydrocarbons 0.1 ppm, Carbon Monoxide 0.1 ppm, Carbon Dioxide 0.1 ppm.9. Hazards9.1 Hydrogen is a highly flammable
31、gas. Improper handlingof high pressure hydrogen or compressed gas cylinders con-taining calibrate compound, air, nitrogen, hydrogen, or heliumcan result in explosion. Hydrogen and compressed gas stan-dards should only be handled in well ventilated locations awayfrom sparks and flames. Rapid release
32、of nitrogen or heliumcan result in asphyxiation. Compressed air supports combus-tion. Read and follow all precautionary statements on theproduct labels.10. Calibration and Standardization10.1 A multipoint calibration curve is prepared, using stan-dard concentrations of 10 ppb, 50 ppb, and 100 ppb of
33、 methylD7676 182fluoride in hydrogen, on a monthly basis or whenever theinstrument is repaired or configuration is changed. Othercompounds may be used for standardization in compliancewith local requirements or regulations.10.2 The instrument calibration is checked daily with the50 ppb calibration g
34、as standard. The response should fallwithin 10 % of the value expected based upon the calibrationcurve. If the performance does not meet this criteria, systemmaintenance and multipoint recalibration are required.10.3 The calibration gas standard is flowed through the gassampling system until all air
35、 is purged out.10.4 The calibration gas standard is injected into the gaschromatograph and simultaneously the integrator or otherrecording device is started.10.5 Total area counts are recorded on the integrator orother recording device.10.6 Repeat three times. Average the standard area counts.The pe
36、rcent relative standard deviation of the calibration areacounts should be less than 10 %. If the performance does notmeet this criteria, system maintenance and multipoint recali-bration are required.10.7 Use the area counts of the three calibration concentra-tions to develop a calibration curve for
37、the analyzer.11. Procedure11.1 Sampling at the sample source shall always be donesafely in a manner that ensures that a representative sample isbeing analyzed. Lack of precision and accuracy in using thismethod can most often be attributed to improper samplingprocedures. (See Practices D3700, D1265,
38、 and D7606.)11.2 Before any samples are analyzed, a sample blank ofhydrogen is used to evaluate system cleanliness.11.2.1 Zero hydrogen is flowed through the gas samplingsystem until all air is purged out.11.2.2 Zero hydrogen blank is injected into the gas chro-matograph and simultaneously the integ
39、rator or other recordingdevice is started.11.2.3 Total blank area counts are recorded on the integratoror other recording device.11.2.4 The total blank area counts should be less than 1 % ofthe calibration standard area counts.ABlankACalx100 % , 1.0 % (1)11.3 If the performance does not meet this cr
40、iteria, systemmaintenance is required.11.4 The gas sample is flowed through the gas samplingsystem until all air is purged out.11.5 The sample is injected into the gas chromatograph andsimultaneously the integrator or other recording device isstarted.11.6 Total area counts are recorded on the integr
41、ator or otherrecording device.11.7 Repeat three times. Average the sample area counts.The percent relative standard deviation of the calibration areacounts should be less than 10 %. If the performance does notmeet this criteria, system maintenance and multipoint recali-bration are required.12. Calcu
42、lation or Interpretation of Results12.1 The sample passes the organic halide contaminationscreening if the average area counts for the sample are less thanthe 10 % of the average area counts for the calibrationstandard, although, any response above that of the sampleblank should be noted.ASampleACal
43、x100 % , 10.0 % (2)12.2 Samples that do not pass the criteria for organic halidecontamination screening shall be tested for organic halideusing Test Method D7892.13. Report13.1 Report if the sample passes or fails organic halidescreening test.14. Keywords14.1 hydrogen quality; PEM fuel cells; total
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