1、Designation: D7649 10 (Reapproved 2017)Standard Test Method forDetermination of Trace Carbon Dioxide, Argon, Nitrogen,Oxygen and Water in Hydrogen Fuel by Jet Pulse Injectionand Gas Chromatography/Mass Spectrometer Analysis1This standard is issued under the fixed designation D7649; the number immedi
2、ately 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 t
3、est method describes a procedure primarily for thedetermination of carbon dioxide, argon, nitrogen, oxygen andwater in high pressure fuel cell grade hydrogen by gaschromatograph/mass spectrometer (GC/MS) with injection ofsample at the same pressure as sample without pressurereduction, which is calle
4、d “Jet Pulse Injection”.The proceduresdescribed in this method were designed to measure carbondioxide at 0.5micromole per mole (ppmv), Argon 1 ppmv,nitrogen 5 ppmv and oxygen 2 ppmv and water 4 ppmv.1.2 The values stated in SI units are standard. The valuesstated in inch-pound units are for informat
5、ion only.1.3 The mention of trade names in standard does notconstitute endorsement or recommendation for use. Othermanufacturers of equipment or equipment models can be used.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibil
6、ity 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.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in th
7、e Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 Other Standards:SAE TIR J2719 Information Report on the Development ofa Hydrogen Quality Gu
8、ideline for Fuel Cell VehiclesApril200823. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 absolute pressurepressure measured with referenceto absolute zero pressure, usually expressed as kPa, mm Hg,bar or psi. All the pressures mentioned in this method areabsolute pressure.3.1.2
9、 constituentA component (or compound) foundwithin a hydrogen fuel mixture.3.1.3 contaminantimpurity that adversely affects the com-ponents within the fuel cell system or the hydrogen storagesystem by reacting with its components. An adverse effect canbe reversible or irreversible.3.1.4 dynamic calib
10、rationcalibration of an analytical sys-tem using calibration gas standard generated by diluting knownconcentration compressed gas standards with hydrogen, asused in this method for carbon dioxide, argon, nitrogen andoxygen (7.3 and 7.4).3.1.5 extracted ion chromatogram (EIC)a GC/MS chro-matogram whe
11、re a selected ion is plotted to determine thecompound(s) of interest.3.1.6 fuel cell grade hydrogenhydrogen satisfying thespecifications in SAE TIR J2719.3.1.7 hydrogen fuelhydrogen to be tested without compo-sitional change due to sample introduction, etc.3.1.8 jet pulse injectionhigh pressure hydr
12、ogen fuelsample is introduced instantaneously at the same pressure intoGC/MS.3.1.9 relative humidityratio of actual pressure of existingwater vapor to maximum possible pressure of water vapor inthe atmosphere at the same temperature, expressed as apercentage.3.1.10 response factor (RF)-the amount in
13、 volume (L) ofan analyte divided by the EIC area of the analyte.3.1.11 static calibrationcalibration of an analytical sys-tem using standards in a matrix, state or manner different thanthe samples to be analyzed, as used in this method for waterconcentration in hydrogen.3.2 Acronyms:1This test metho
14、d is under the jurisdiction ofASTM Committee D03 on GaseousFuels and is the direct responsibility of Subcommittee D03.14 on Hydrogen andFuel Cells.Current edition approved April 1, 2017. Published April 2017. Originallyapproved in 2010. Last previous edition approved in 2010 as D7649-10. DOI:10.1520
15、/D764910R17.2Available from SAE International (SAE), 400 Commonwealth Dr., Warrendale,PA 15096-0001, http:/aerospace.sae.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with i
16、nternationally 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.13.2.1 FCVfuel cell vehicle.3.2.2 PEMFCproton
17、 exchange membrane fuel cell.4. Summary of Test Method4.1 The simultaneous analysis of carbon dioxide, argon,nitrogen, oxygen and water at 0.5 5 ppmv (micromole permole) in hydrogen fuel samples from fueling stations ischallenging due to high hydrogen fuel sample pressure andpossible contaminations
18、from ambient air.4.2 In this method, a small stainless steel loop is initiallypressurized with high pressure hydrogen standard or samplewithout any pressure regulation or restriction (“Sample LoopPressurization”, Fig. 1). The hydrogen in the loop is thenreleased entirely as a “jet pulse” into a T-un
19、ion which splitssample into a 0.25 m ID 30 m long capillary column and anelectronic flow controller (EFC) used to vent excess hydrogento the atmosphere (“Jet Pulse Injection”, Fig. 2). Less than 1%of hydrogen enters the capillary column with the remainingsample venting to atmosphere through EFC. As
20、demonstratedin Appendix X1, the hydrogen volume “jet pulse injected” intothe capillary column is a constant volume and independent ofthe sample loop pressure when the sample loop pressure is over90 psi. Therefore, the constant hydrogen volume from stan-dards or samples is GC/MS analyzed in regardles
21、s of standardor sample pressures.4.3 Jet pulse injected volume into the capillary column isapproximate 100 L (In Appendix X1, this volume is calcu-lated to be 115L under the analytical conditions described inAppendix X1). When a 2-mL of sample loop is pressurized to200 psi, the hydrogen in the loop
22、is (200 psi/14.7psi)2mLor 27 mL. Hence, 99.5% of the hydrogen sample vents toatmosphere. This type of “Jet Pulse Injection” has been foundacceptable for the analysis of high pressure hydrogen fuelsample since the hydrogen volume injected is independent ofthe pressures of hydrogen standards or sample
23、s. Consequentlyit is unnecessary to regulate standards and hydrogen samples tothe same pressure. In addition to possible trace leaks or airtrapped inside, regulators are not recommended as moisture onthe regulator surface can be released into the sample resultingin a high moisture determination.4.4
24、A mass spectrometer provides sensitive and selectivedetection towards carbon dioxide, argon, nitrogen, oxygen andwater.5. Significance and Use5.1 Low operating temperature fuel cells such as protonexchange membrane fuel cells (PEMFCs) require high purityhydrogen for maximum performance. The followin
25、g are thereported effects (SAE TIR J2719) of the compounds deter-mined by this test method.5.2 Carbon Dioxide (CO2), acts largely as a diluent, how-ever in the fuel cell environment CO2can be transformed intoCO.5.3 Water (H2O), is an inert impurity, as it does not affectthe function of a fuel cell s
26、tack; however, it provides atransport mechanism for water-soluble contaminants, such asNa+or K+. In addition, it may form ice on valve internalsurface at cold weather or react exothermally with metalhydride used as hydrogen fuel storage.5.4 Inert Gases (N2and Ar), do not normally react with afuel ce
27、ll components or fuel cell system and are considereddiluents. Diluents can decrease fuel cell stack performance.5.5 Oxygen (O2), in low concentrations is considered aninert impurity, as it does not adversely affect the function of afuel cell stack; however, it is a safety concern for vehicle onboard
28、 fuel storage as it can react violently with hydrogen togenerate water and heat.FIG. 1 Sample Loop PressurizationD7649 10 (2017)26. Apparatus6.1 Mass Spectrometer (MS)The MS can perform masscalibration with a scanning range from m/e 15 to 650. Thebackground peak intensities of water, nitrogen, argon
29、, oxygenand carbon dioxide in the mass spectrum of FC-43(perfluorotributylamine), used for mass calibration, should beless than 10% of m/e 69 to demonstrate a backgroundacceptable for the determination of these analytes beforebeginning sample analysis. All analytes determined accordingto this method
30、 have a molecular mass less than 44 amu;therefore, the mass scanning range of m/e 15 to 50 is typicallyused.6.2 Data SystemAcomputer or other data recorder loadedwith appropriate software for data acquisition, data reduction,and data reporting and possessing the following capabilities isrequired:6.2
31、.1 Graphic presentation of the total ion chromatogram(TIC) and extracted ion chromatogram (EIC).6.2.2 Digital display of chromatographic peak areas.6.2.3 Identification of peaks by retention time and massspectra.6.2.4 Calculation and use of response factors.6.2.5 External standard calculation and da
32、ta presentation.6.3 Gas chromatography (GC)Chromatographic systemcapable of obtaining retention time repeatability of 0.05 min (3s) throughout the analysis.6.3.1 Interface with MSA heated interface connecting theGC column to the MS ion source.6.3.2 GC ColumnA 0.25mm ID 30m 0.25 m film thick-ness DB-
33、5 column has been successfully used to perform thisanalysis. Other capillary columns may be used providedchromatographic peaks do not significantly tail. One end of theGC column is connected to the Jet Pulse Split (6.4.5) and theother end is connected to the ion source inlet of a massspectrometer.6.
34、3.3 Carrier GasUltra high purity hydrogen is used ascarrier gas. Use of helium carrier gas results in unacceptablebroadening of the water chromatographic peak. An example ofwater peaks is shown in Fig. 3.6.3.4 GC InjectorAn injector port with a glass insert anda septum is connected through a116 in.
35、OD stainless steeltubing to a jet pulse split (6.4.5) in the inlet system (6.4). Theinjector temperature is set to at 220C to ensure that all watervapor in injected ambient air are not condensed in the injector.The GC column and total split flow rate are electronically setat 1.5 and 75 mL/min, respe
36、ctively. The GC total split flowincludes a GC septum purge flow of 3mL/min (Fig. 1 and Fig.2) and GC injector split flow of 72mL/min.6.4 Inlet SystemA system introduces high pressuresamples or standards into GC/MS for analysis. The sample orstandard enter the inlet system through “Sample Loop Pressu
37、r-ization” (Fig. 1) and then leave the inlet system to GC/MSthrough “Jet Pulse Injection” (Fig. 2). While the inlet system isin “Sample Loop Pressurization”, the sample loop (6.4.4)ispressurized directly with hydrogen samples or calibrationstandards without pressure regulation or flow restriction.Af
38、terwards, a six-port sample valve (6.4.1) switches the inletsystem to “Jet Pulse Injection”, in which pressurized hydrogenin the sample loop is released instantaneously onto the GCcolumn (6.3.2) and jet pulse split (6.4.5). Since the samplepressure is high, all parts of the inlet system must be capa
39、ble ofworking at pressures of 1500 psi or higher.6.4.1 Six Ports ValveThis valve is used to switch from“Sample Loop Pressurization” (Fig. 1) to “Jet Pulse Injection”(Fig. 2).6.4.2 Samples and Calibration StandardsAll calibrationstandards and samples are prepared or collected in 1800 psipressure rate
40、d containers with a DOT 3A1800 label (UnitedStated Department of Transportation mandated label) affixed tothe outside surface. All calibration standards and samples areFIG. 2 Jet Pulsed InjectionD7649 10 (2017)3connected to the inlet system before beginning an analyticsequence to minimize the potent
41、ial for air or moisture contami-nation due to addition or replacement of standard or samplecontainers.6.4.3 Vacuum Pumpan oil vacuum pump that can pumpdown to 50 mtorr or less.6.4.4 Sample Loopstainless steel tubing with116 in. ODand 2 mL inside volume. Both ends of the sample loop areconnected to a
42、 six port valve (6.4.1).6.4.5 Jet Pulse Splita T-union connects the followingthree portions.6.4.5.1 Six port valve (6.4.1)6.4.5.2 Inlet of GC column (6.4.2)6.4.5.3 Inlet of an electronic flow controller (EFC) with itsoutlet to ambient air. The flow rate of this EFC is alwayselectronically set at 150
43、mL/min to vent most of the GC injectorsplit flow (72mL/min) during “Sample Loop Pressurization”(Fig. 1) and released hydrogen from pressurized sample loop in“Jet Pulse Injection” (Fig. 2).6.4.6 Digital Vacuum Gaugecapable of measuring abso-lute pressure at vacuum range 0 to 12,000 milli-torr (mtorr
44、or10-3torr). For the vacuum range from 0 to 1000 mtorr, theaccuracy is 6 10% or6 10 mtorr, whichever is larger.6.4.7 Digital Pressure GaugesTwo types of digital pres-sure gauges are required. A pressure gauge 0 to 1000 psig isused to measure sample and standard final pressure. Anotherdigital pressur
45、e gauge in the low and narrow pressure range,such as 0 to 2000 torr, is used to measure the pressure of puregases in initial standard preparation.6.4.8 Pressure RegulatorA 10,000 psi pressure regulatoris used to reduce UHP hydrogen pressure to approximate 400psi for calibration standard preparation.
46、 It is also used topressurize the inlet system during method blank analysis, andduring inlet system flushing.7. Reference Standards7.1 Typical reference standards are listed in Fig. 1.Twostandards prepared in helium containing 100 ppmv O2and 100FIG. 3 m/e18 Extracted Ion Chromatogram of Sample Analy
47、sis with Co-Injection of Ambient AirD7649 10 (2017)4ppmv N2, are commercial available. Remaining standardslisted in Fig. 1 are prepared as per below.7.2 0.5% CO2,Ar,N2and O2in hydrogenAn evacuated1-L cylinder is connected to four pressure-regulated com-pressed gas cylinders containing reagent or UHP
48、 grade CO2,Ar, N2and O2. The system is evacuated to less than 500 mtorrwith all the regulators opened and the main cylinder valvesclosed. With the system isolated from vacuum pump, the 1-Lcylinder valve is opened and 100 torr of each target compoundfrom the compressed gas cylinders is expanded into
49、the systemand 1-Lcylinder. The 1-Lcylinder is then pressured using UHPhydrogen to 390 psi, or 390/14.7 760 = 2.02 104torr. Theconcentration of each target compound is 100 torr/(2.02104torr) = 0.5 %. This standard can be used as a co-injectionstandard (9.3.3) and further diluted to prepare a 5 ppmvstandard (7.3). The UHPhydrogen used for preparation of both0.5% (7.2) and 5 ppmv standards (7.3) are free from CO2,Ar,N2and O2by this test method.7.3 5ppmv CO2,Ar,N2and O2in hydrogen:7.3.1 Close all the valves in Fig. 1 except leave Valves 2,
