1、Designation: D2504 88 (Reapproved 2010)Standard Test Method forNoncondensable Gases in C2and Lighter HydrocarbonProducts by Gas Chromatography1This standard is issued under the fixed designation D2504; the number immediately following the designation indicates the year oforiginal adoption or, in the
2、 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 covers the determination of hydrogen,nitrogen, oxygen, and carbon mono
3、xide 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 include them.1.2 The values stated in SI units are to be regarded as thestandard. The values given in pa
4、rentheses 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 establish appro-priate safety and health practices and determine the applica-bility of regulatory limita
5、tions prior to use. For some specifichazard statements, see the Annex A1.2. Referenced Documents2.1 ASTM Standards:2D2505 Test Method for Ethylene, Other Hydrocarbons, andCarbon Dioxide in High-Purity Ethylene by Gas Chroma-tographyE260 Practice for Packed Column Gas ChromatographyF307 Practice for
6、Sampling Pressurized Gas for Gas Analy-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 chromatographicsystem using molecular sieves as the solid adsorbent. Theconcentration of the gases t
7、o 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 the sample,interferes with oxygen determination.4. Significance and Use4.1 The presence of trace amou
8、nts 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 use as aninternal quality control tool and for use in development orresearch work.5. Apparatus5.1 Chrom
9、atographAny 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, with a peak height of at least 2mm without loss of resolution.5.2 DetectorsThermal ConductivityIf a me
10、thanation 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 detector and hydrogen added as a reduction gas. Details onthe preparation and use of the reactor are
11、 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, or aluminum tubing may be used. Thecolumns chosen must afford a resolution such that the depth ofthe
12、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.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and i
13、s the direct responsibility of SubcommitteeD02.D0.02 on Ethylene.Current edition approved May 1, 2010. Published May 2010. Originallyapproved in 1966. Last previous edition approved in 2004 as D2504 88 (2004)E1.DOI: 10.1520/D2504-88R10.2For referenced ASTM standards, visit the ASTM website, www.astm
14、.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 (CGA), 4221 Walney Rd., 5thFloor, Chantilly, VA 20151-2923, http:/.1Copyright ASTM
15、 International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.6 OvenThe 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
16、oven may be a thermostated piece of1-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 copper tubing is not recommended with samplescontaining acetylene as this could lead to the formation
17、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 to 60-mesh sieve size is desired, but is notavailable, it may be prepared as described in 8.1.6.2
18、 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 sieve, a 3-m by 6.35-mm outside diameter column of 40 to60-mesh 5Asieve, and a 7.7-m by 6.35-mm out
19、side 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 toprepare synthetic standard samples as described in Test MethodD2505.(WarningFlammable gases. Hazard
20、ous 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 blends are commercially availablefrom numerous sources and can be used as the syntheticstandard sample
21、s.6.4 Carrier GasesArgon or helium.NOTE 3Practice E260 contains information that will be helpful tothose using this test method.7. Sampling7.1 Samples shall be supplied to the laboratory in high-pressure sample cylinders, obtained using the proceduresdescribed in Practice F307 or similar methods.8.
22、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 work of preparing molecular sieves and packingcolumns with this material shall be done rapidly, pre
23、ferablyunder 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 about 5 mL/min during this time. The nitrogen rateis not critical and can be measured by any convenient
24、 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.Fill rapidly with the screened and activated molecular sieves,adding the latter in 1-g increments. V
25、ibrate 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 instrument. Regen-erate the column in the oven in the same manner as describedin 8.1 whenever the oxyge
26、n 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 36 to 60 mL/min and temperatures of 50to 60C have been used successfully.9.2 Prepare at least three s
27、ynthetic 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 preparation of thesecond, third, and following calibration samples it is alwayspreferable not to dilute the
28、first sample.NOTE 5Synthetic standard samples should be prepared as describedin Test Method D2505.9.3 Inject a known volume of one of the standard samples,using a minimum of 1 mL for detecting 2 ppmv.NOTE 6Use of a reverse-flow arrangement will facilitate removal ofheavier gases and decrease the ela
29、psed 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 compound againstthe concentration of the compounds in ppmv. The peak areacan be determined by any metho
30、d that meets the precisionrequirements of Section 12. Methods found to be acceptableinclude planimetering, integration (electronic or mechanical orcomputer processing), and triangulation.10. Procedure10.1 Connect the sample cylinder containing a gaseoussample to the gas sample valve with a metal tub
31、e 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 and calibration gasmust be the same in the sample loop) and record the peak areasor peak heights desi
32、red.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 showing hydrogen, oxygen, and nitrogen in ethylene ispresented in Fig. 1.12. Precision and Bias12.1
33、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 same operator with the sameapparatus under constant operating conditions on identical testD2504 88 (20
34、10)2material would, in the long run, and in the normal and correctoperation of the test method, exceed the following values onlyin one case in twenty:Component Range, ppmv Repeatability, ppmvOxygen 10150 15Nitrogen 100700 72Carbon Monoxide 020 3Hydrogen 015 212.1.2 ReproducibilityThe difference betw
35、een 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 of the testmethod, exceed the following values only in one case intwenty:Component Range, ppmv Reproducib
36、ility, 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 that the poor reproduc-ibility is attributable to the difficulty of excluding air from these samples.Pre
37、cise 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 the procedure in this test method hasnot yet been determined but it is now under consideration bythe resp
38、onsible committee.13. Keywords13.1 carbon dioxide; ethane; ethylene; gas chromatography;hydrocarbons; methane; nitrogenANNEX(Mandatory Information)A1. WARNING STATEMENTSA1.1 Flammable GasKeep away from heat, sparks, and open flame.Use with adequate ventilation.Never drop cylinder. Make sure cylinder
39、 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.Keep cylinder valve closed when not in use.Do not inhale.Do not e
40、nter storage areas unless adequately ventilated.Stand away from cylinder outlet when opening cylindervalve.Keep cylinder from corrosive environment.FIG. 1 Typical Chromatogram for Hydrogen, Oxygen and NitrogenD2504 88 (2010)3Do not use cylinder without label.Do not use dented or damaged cylinder.For
41、 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 regulator. Release regulator tensionbefore opening cylinder.Do not transfer to cylinder other than one in which ga
42、s 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 and away from heat.Keep cylinder from corrosive environment.Do not use cylinder without label.Do not use d
43、ented 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 with adequate ventilation.Never drop cylinder. Make sure cylinder is supported at alltimes.Keep cylinder out
44、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.Keep cylinder valve closed when not in use.Do not inhale.Do not enter storage areas unless adequately ventila
45、ted.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 control equipment.Use only with equipment condition for oxygen service bycarefully cleaning to remove oil, gre
46、ase 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 pressure regulator. Release regulator tensionbefore opening cylinder valve.All equipment and containers used
47、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. Make sure cylinder is secured at alltimes.Keep cylinder valve closed when not in use.Stand away from outl
48、et 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 cylinder without label.Do not use dented or damaged cylinders. See CompressedGas Association booklets G-4 and G-4.
49、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 METHANATION REACTORX1.1 ScopeX1.1.1 This method describes the preparation of a metha-nation reactor t
