1、Designation: D 2504 88 (Reapproved 2004)e1An American National StandardStandard Test Method forNoncondensable Gases in C2and Lighter HydrocarbonProducts by Gas Chromatography1This standard is issued under the fixed designation D 2504; the number immediately following the designation indicates the ye
2、ar 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 (e) indicates an editorial change since the last revision or reapproval.e1NOTEWarning notes moved into text editorially in November 2004.
3、1. Scope1.1 This test method covers the determination of hydrogen,nitrogen, oxygen, and carbon monoxide in the parts per millionvolume (ppmv) range in C2and lighter hydrocarbon products.This test method should be applicable to light hydrocarbonsother than ethylene, but the test program did not inclu
4、de them.1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.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 estab
5、lish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. For some specifichazard statements, see the Annex A1.2. Referenced Documents2.1 ASTM Standards:2D 2505 Test Method for Ethylene, Other Hydrocarbons, andCarbon Dioxide In High-Purity
6、 Ethylene by Gas Chroma-tographyE 260 Practice for Packed Column Gas ChromatographyF 307 Practice for Sampling Pressurized Gas for GasAnaly-sis2.2 Other Standard:3Compressed Gas Association Booklets G-4 and G-4.1 onthe use of oxygen.3. Summary of Test Method3.1 The sample is separated in a gas-solid
7、 chromatographicsystem using molecular sieves as the solid adsorbent. Theconcentration of the gases to be determined is calculated fromthe recorded peak heights or peak areas. Argon can be used asa carrier gas for the determination of hydrogen in concentra-tions below 100 ppmv. Argon, if present in
8、the sample,interferes with oxygen determination.4. Significance and Use4.1 The presence of trace amounts of hydrogen, oxygen, andcarbon monoxide can have deleterious effects in certain pro-cesses using hydrocarbon products as feed stock. This testmethod is suitable for setting specifications, for us
9、e as aninternal quality control tool and for use in development orresearch work.5. Apparatus5.1 ChromatographAny chromatographic instrumenthaving either a thermal conductivity or ionization detector withan overall sensitivity sufficient to detect 2 ppmv or less of thecompounds listed in the scope, w
10、ith a peak height of at least 2mm without loss of resolution.5.2 DetectorsThermal ConductivityIf a methanation re-actor is used, a flame ionization detector is also required. Todetermine carbon monoxide with a flame ionization detector, amethanation reactor must be inserted between the column andthe
11、 detector and hydrogen added as a reduction gas. Details onthe preparation and use of the reactor are given in AppendixX1.5.3 Constant-Volume Gas Sampling Valve.5.4 ColumnAny column or set of columns that is capableof resolving the components listed in the scope can be used.Copper, stainless steel,
12、or aluminum tubing may be used. Thecolumns chosen must afford a resolution such that the depth ofthe valleys ahead of the trace peak is no less than 50 % of thetrace peak height.5.5 RecorderA recorder with a full-scale response of 2 sor less and a maximum rate of noise of 60.3 % of full scale.5.6 Ov
13、enThe oven used for activating molecular sievesmust be maintained at 260 to 288C (500 to 550F) and shouldbe designed so that the gases may be displaced continuously bya stream of inert gas. The oven may be a thermostated piece of1This test method is under the jurisdiction of ASTM Committee D02 onPet
14、roleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.D0 on Hydrocarbons for Chemical and Special Uses.Current edition approved Nov. 1, 2004. Published November 2004. Original-lyapproved in 1966. Last previous edition approved in 1998 as D 2504 88 (1998).2For referenced
15、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.3Available from Compressed Gas Association, 1253 Jefferson Davis Highway,Arli
16、ngton, VA, 22202.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.1-in. pipe about 0.3 m (1 ft) in length. Electrical heating tapesor other means may be used for heating provided the heat isdistributed uniformly.NOTE 1The use of coppe
17、r tubing is not recommended with samplescontaining acetylene as this could lead to the formation of potentiallyexplosive copper acetylide.6. Reagents and Materials6.1 Molecular Sieves, 5A, 13A, or 13XAny mesh sizescan be used so long as sensitivity and resolution are maintained(see Note 2). If a 40
18、to 60-mesh sieve size is desired, but is notavailable, it may be prepared as described in 8.1.6.2 Coconut Charcoal, 30 to 60-mesh sieve size (optional).NOTE 2Columns that have been found to give the desired separationinclude a 1-m by 3.175-mm outside diameter column of 100 to 120 mesh5A molecular si
19、eve, a 3-m by 6.35-mm outside diameter column of 40 to60-mesh 5Asieve, and a 7.7-m by 6.35-mm outside diameter column with13A or 13X sieve in the first 7.4 m and charcoal in the 0.3 m.6.3 Gases for CalibrationPure or research grade hydro-gen, oxygen, nitrogen, and carbon monoxide will be needed topr
20、epare synthetic standard samples as described in Test MethodD 2505.(WarningFlammable gases. Hazardous pressure.See Annexes A1.1-A1.5.) (WarningFlammable. Poison.Harmful if inhaled. Dangerous when exposed to flame. SeeAnnex A1.5.) (WarningHazardous pressure. See AnnexA1.2.) Certified calibration blen
21、ds are commercially availablefrom numerous sources and can be used as the syntheticstandard samples.6.4 Carrier GasesArgon or helium.NOTE 3Practice E 260 contains information that will be helpful tothose using this test method.7. Sampling7.1 Samples shall be supplied to the laboratory in high-pressu
22、re sample cylinders, obtained using the proceduresdescribed in Practice F 307 or similar methods.8. Preparation of Apparatus8.1 Chromatographic Column PackingCrush in a porce-lain mortar and sieve to 40 to 60-mesh size about 200 g ofmolecular sieves 5A in order to have enough for severalcolumns. All
23、 work of preparing molecular sieves and packingcolumns with this material shall be done rapidly, preferablyunder a blanket of dry nitrogen in order to minimize moistureabsorption. Heat the screened molecular sieves in an oven at274 6 14C (525 6 25F) for 24 h purging with dry nitrogenat a rate of abo
24、ut 5 mL/min during this time. The nitrogen rateis not critical and can be measured by any convenient meanssuch as an orifice meter, rotameter, manometer, etc. Do not usea wet test meter.8.2 Chromatographic ColumnPurge the metal tubing withdry nitrogen. Insert a small amount of glass wool in the end.
25、Fill rapidly with the screened and activated molecular sieves,adding the latter in 1-g increments. Vibrate the column, addingadditional sieves during this period, if necessary, to fill. Inserta small amount of glass wool in the top. Bend the column in theshape required to fit the chromatographic ins
26、trument. Regen-erate the column in the oven in the same manner as describedin 8.1 whenever the oxygen is not completely separated fromthe nitrogen peak.9. Calibration9.1 Bring the equipment and column to equilibrium andmaintain a constant carrier gas rate and temperature.NOTE 4Carrier gas rates of 3
27、6 to 60 mL/min and temperatures of 50to 60C have been used successfully.9.2 Prepare at least three synthetic standard samples con-taining the compounds to be determined over the range ofconcentration desired in the products to be analyzed, using thepure gases or the certified blend. For the preparat
28、ion of thesecond, third, and following calibration samples it is alwayspreferable not to dilute the first sample.NOTE 5Synthetic standard samples should be prepared as describedin Test Method D 2505.9.3 Inject a known volume of one of the standard samples,using a minimum of 1 mL for detecting 2 ppmv
29、.NOTE 6Use of a reverse-flow arrangement will facilitate removal ofheavier gases and decrease the elapsed time of analysis.9.4 Record all of the desired peaks on each of the syntheticblends prepared.9.5 Prepare a chart for each compound, plotting the peakheight of the compound or peak area of the co
30、mpound againstthe concentration of the compounds in ppmv. The peak areacan be determined by any method that meets the precisionrequirements of Section 12. Methods found to be acceptableinclude planimetering, integration (electronic or mechanical orcomputer processing), and triangulation.10. Procedur
31、e10.1 Connect the sample cylinder containing a gaseoussample to the gas sample valve with a metal tube and allow thesample to flow from the sample tube for about12 min. at a rateof 70 to 100 mL/min.10.2 Inject into the instrument the same volume of sampleas used for calibration, (pressure of sample
32、and calibration gasmust be the same in the sample loop) and record the peak areasor peak heights desired.11. Calculation11.1 From the peak height or area of the compound in thesample, determine the moles per million of the compoundusing the charts prepared in calibration. A typical characteriza-tion
33、 showing hydrogen, oxygen, and nitrogen in ethylene ispresented in Fig. 1.12. Precision and Bias12.1 The precision of this test method as determined bystatistical examination of interlaboratory results is as follows:12.1.1 RepeatabilityThe difference between successivetest results, obtained by the s
34、ame operator with the sameapparatus under constant operating conditions on identical testmaterial would, in the long run, and in the normal and correctoperation of the test method, exceed the following values onlyin one case in twenty:D 2504 88 (2004)e12Component Range, ppmv Repeatability, ppmvOxyge
35、n 10150 15Nitrogen 100700 72Carbon Monoxide 020 3Hydrogen 015 212.1.2 ReproducibilityThe difference between two singleand independent results obtained by different operators work-ing in different laboratories on identical test material would, inthe long run, and in the normal and correct operation o
36、f the testmethod, exceed the following values only in one case intwenty:Component Range, ppmv Reproducibility, ppmvOxygen 10150 155Nitrogen 1001000 875Carbon Monoxide 020 7Hydrogen 015 8NOTE 7The committee believes the methods for oxygen and nitrogenare better than the precision would indicate, and
37、that the poor reproduc-ibility is attributable to the difficulty of excluding air from these samples.Precise results are heavily dependent upon extreme care in sampling andhandling. The use of continuous analyzers is preferred, and is recom-mended whenever circumstances permit.12.2 BiasThe bias of t
38、he procedure in this test method hasnot yet been determined but it is now under consideration bythe responsible committee.13. Keywords13.1 carbon dioxide; ethane; ethylene; gas chromatography;hydrocarbons; methane; nitrogenANNEX(Mandatory Information)A1. WARNING STATEMENTSA1.1 Flammable GasKeep away
39、 from heat, sparks, and open flame.Use with adequate ventilation.Never drop cylinder. Make sure cylinder is supported at alltimes.Keep cylinder out of sun and away from heat.Always use a pressure regulator. Release regulator tensionbefore opening cylinder.Do not transfer cylinder contents to another
40、 cylinder. Do notmix gases in cylinder.Keep cylinder valve closed when not in use.Do not inhale.Do not enter storage areas unless adequately ventilated.Stand away from cylinder outlet when opening cylindervalve.Keep cylinder from corrosive environment.Do not use cylinder without label.FIG. 1 Typical
41、 Chromatogram for Hydrogen, Oxygen and NitrogenD 2504 88 (2004)e13Do not use dented or damaged cylinder.For technical use only. Do not inhale.A1.2 Compressed GasesKeep container closed.Use with adequate ventilation.Do not enter storage areas unless adequately ventilated.Always use a pressure regulat
42、or. Release regulator tensionbefore opening cylinder.Do not transfer to cylinder other than one in which gas isreceived. Do not mix gases in cylinders.Do not drop cylinder. Make sure cylinder is supported at alltimes.Stand away from cylinder outlet when opening cylindervalve.Keep cylinder out of sun
43、 and away from heat.Keep cylinder from corrosive environment.Do not use cylinder without label.Do not use dented or damaged cylinder.For technical use only. Do not use for inhalation purposes.A1.3 HydrogenWarningExtremely flammable gas under pressure.Keep away from heat, spark, and open flame.Use wi
44、th adequate ventilation.Never drop cylinder. Make sure cylinder is supported at alltimes.Keep cylinder out of sun and away from heat.Always use a pressure regulator. Release regulator tensionbefore opening cylinder.Do not transfer cylinder contents to another cylinder. Do notmix gases in cylinder.Ke
45、ep cylinder valve closed when not in use.Do not inhale.Do not enter storage areas unless adequately ventilated.Stand away from cylinder outlet when opening cylindervalve.Keep cylinder from corrosive environment.A1.4 OxygenKeep oil and grease away. Do not use oil or grease onregulators, gauges or con
46、trol equipment.Use only with equipment condition for oxygen service bycarefully cleaning to remove oil, grease and other combus-tibles.Keep combustibles away from oxygen and eliminate ignitionsources.Keep surfaces clean to prevent ignition or explosion, or both,on contact with oxygen.Always use a pr
47、essure regulator. Release regulator tensionbefore opening cylinder valve.All equipment and containers used must be suitable andrecommended for oxygen service.Never attempt to transfer oxygen from cylinder in which it isreceived to any other cylinder.Do not mix gases in cylinders.Do not drop cylinder
48、. Make sure cylinder is secured at alltimes.Keep cylinder valve closed when not in use.Stand away from outlet when opening cylinder valve.For technical use only. Do not use for inhalation purposes.Keep cylinder out of sun and away from heat.Keep cylinder from corrosive environment.Do not use cylinde
49、r without label.Do not use dented or damaged cylinders. See CompressedGas Association booklets G-4 and G-4.1 for details of safepractice in the use of oxygen.A1.5 Carbon MonoxideHarmful or fatal if inhaled.Dangerous when exposed to flame.Keep away from heat, sparks, and open flame.Use with adequate ventilation.Use fume hood whenever possible.Avoid build-up of vapor and eliminate all sources of igni-tion, especially nonexplosion proof electrical apparatus andheaters.Avoid breathing.APPENDIX(Nonmandatory Information)X1. PREPARATION OF METHANATI
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