1、Designation: D 6228 98 (Reapproved 2003)Standard Test Method forDetermination of Sulfur Compounds in Natural Gas andGaseous Fuels by Gas Chromatography and FlamePhotometric Detection1This standard is issued under the fixed designation D 6228; the number immediately following the designation indicate
2、s 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 (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of
3、individualvolatile sulfur-containing compounds in gaseous fuels by gaschromatography (GC) with flame photometric detection (FPD).The detection range for sulfur compounds is from 20 to 20 000picograms (pg) of sulfur. This is equivalent to 0.02 to 20mg/m3or 0.014 to 14 ppmv of sulfur based upon the an
4、alysisof a 1-mL sample.1.2 This test method describes a GC-FPD method using aspecific capillary GC column. Other GC-FPD methods, withdifferences in GC column and equipment setup and operation,may be used as alternative methods for sulfur compoundanalysis with different range and precision, provided
5、thatappropriate separation of the sulfur compounds of interest canbe achieved.1.3 This test method does not intend to identify all indi-vidual sulfur species. Total sulfur content of samples can beestimated from the total of the individual compounds deter-mined. Unknown compounds are calculated as m
6、onosulfur-containing compounds.1.4 The values stated in SI units are to be regarded asstandard. The values stated in inch-pound units are for infor-mation only.1.5 This standard does not purport to address all the safetyconcerns, if any, associated with its use. It is the responsibilityof the user o
7、f this standard to establish appropriate safety andhealth practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:D 1072 Test Method for Total Sulfur in Fuel Gases2D 1265 Practice for Sampling Liquefied Petroleum (LP)GasesManual Metho
8、d3D 1945 Test Method for Analysis of Natural Gas by GasChromatography2D 3609 Practice for Calibration Techniques Using Perme-ation Tubes4D 4468 Test Method for Total Sulfur in Gaseous Fuels byHydrogenolysis and Rateometric Colorimetry2D 4626 Practice for Calculation of Gas ChromatographicResponse Fa
9、ctors5D 5287 Practice for Automatic Sampling of Gaseous Fuels2D 5504 Test Method for Determination of Sulfur Com-pounds in Natural Gas and Gaseous Fuels by Gas Chro-matography and Chemiluminescence2E 840 Practice for Using Flame Photometric Detectors inGas Chromatography62.2 EPA Standards:EPA15 Dete
10、rmination of Hydrogen Sulfide, Carbonyl Sul-fide and Carbon Disulfide Emissions from StationarySources, 40 CFR, Chapter 1, Part 60, Appendix AEPA16 Semicontinuous Determination of Sulfur Emis-sions from Stationary Sources, 40 CFR, Chapter 1, Part60, Appendix A3. Terminology3.1 Abbreviations:3.1.1 A
11、common abbreviation of a hydrocarbon compoundis to designate the number of carbon atoms in the compound.A prefix is used to indicate the carbon chain form, while asubscript suffix denotes the number of carbon atoms, forexample, normal decane = n-C10, isotetradecane = i-C14.3.1.2 Sulfur compounds com
12、monly are referred to by theirinitials, chemical or formula, for example, methyl mercaptan =MeSH, dimethyl sulfide = DMS, carbonyl sulfide = COS,di-t-butyl trisulfide = DtB-TS, and tetrahydothiophene = THTor thiophane.4. Summary of Test Method4.1 Sulfur analysis ideally is performed on-site to elimi
13、natepotential sample deterioration during storage. The reactive1This test method is under the jurisdiction of ASTM Committee D03 on GaseousFuels and is the direct responsibility of Subcommittee D03.05 on Determination ofSpecial Constituents of Gaseous Fuels.Current edition approved May 10, 2003. Pub
14、lished August 2003. Originallyapproved in 1998. Last previous edition approved in 1998 as D 6228 98.2Annual Book of ASTM Standards, Vol 05.06.3Annual Book of ASTM Standards, Vol 05.01.4Annual Book of ASTM Standards, Vol 11.03.5Annual Book of ASTM Standards, Vol 05.02.6Annual Book of ASTM Standards,
15、Vol 03.06.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.nature of sulfur components may pose problems both insampling and analysis. Samples should be collected and storedin containers that are nonreactive to sulfur compounds, such
16、asTedlar7bags. Sample containers should be filled and purged atleast three times to ensure representative sampling. Laboratoryequipment also must be inert, well conditioned, and passivatedwith a gas containing the sulfur compounds of interest toensure reliable results. Frequent calibration and daily
17、 verifica-tion of calibration curve using stable standards are required.Samples should be analyzed within 24 h of collection tominimize sample deterioration. If the stability of analyzedsulfur components is proved experimentally, the time betweencollection and analysis may be lengthened.4.2 A 1-mL s
18、ample of the fuel gas is injected into a gaschromatograph where it is passed through a 60-m, 0.53-mminside diameter (ID), thick film, methyl silicone liquid phase,open tubular partitioning column, or a similar column capableof separating sulfur components.4.3 Flame Photometric DetectorsWhen combuste
19、d in ahydrogen-rich flame, sulfur compounds emit light energycharacteristic to all sulfur species. The light is detected by aphotomultiplier tube (PMT). The PMT response is proportionalto the concentration or the amount of sulfur. All sulfurcompounds including sulfur odorants can be detected by this
20、technique.4.4 Other DetectorsThis test method is written primarilyfor the flame photometric detector. The same gas chromato-graphic (GC) method can be used with other sulfur-specificdetectors provided they have sufficient sensitivity and selectiv-ity to all sulfur compounds of interest in the requir
21、ed measure-ment range.4.5 Other GC Test MethodsThe GC test methods usingsulfur chemiluminescence, reductive rateometric, and electro-chemical detectors are available or under development.5. Significance and Use5.1 Many sources of natural gas and petroleum gasescontain varying amounts and types of su
22、lfur compounds, whichare odorous, corrosive to equipment, and can inhibit or destroycatalysts used in gas processing. Their accurate measurement isessential to gas processing, operation, and utilization.5.2 Small amounts, typically, 1 to 4 ppmv of sulfur odorantcompounds, are added to natural gas an
23、d liquefied petroleum(LP) gases for safety purposes. Some odorant compounds canbe reactive and may be oxidized, forming more stable com-pounds having lower odor thresholds. These gaseous fuels areanalyzed for sulfur odorants to help ensure appropriate odorantlevels for safety.5.3 This test method of
24、fers a technique to determine indi-vidual sulfur species in gaseous fuel and the total sulfur contentby calculation. Gas chromatography is used commonly andextensively to determine other components in gaseous fuelsincluding fixed gas and organic components (see Test MethodD 1945). This test method d
25、ictates the use of a specific GCtechnique with one of the more common detectors for mea-surement.6. Apparatus6.1 ChromatographAny gas chromatograph that has thefollowing performance characteristics can be used.6.1.1 Sample Inlet SystemGas samples are introduced tothe gas chromatograph using an autom
26、ated or manually oper-ated stainless steel gas sampling valve enclosed in a heatedvalve oven, which must be capable of operating continuouslyat a temperature of 50C above the temperature at which thegas was sampled. TFE-fluorocarbon tubing made of fluorinatedethylene propylene (FEP), 316 stainless s
27、teel tubing, or othertubing made of nonpermeable, nonsorbing, and nonreactivematerials, as short as possible and heat traced at the sametemperature, should be used for transferring the sample from asample container to the gas-sampling valve. A 1.0-mL sam-pling loop made of nonreactive materials, suc
28、h as deactivatedfused silica or 316 stainless steel is used to avoid possibledecomposition of reactive sulfur species. Other size fixed-volume sampling loops may be used for different concentrationranges. A 1- to 2-m section of deactivated precolumn attachedto the front of the analytical column is r
29、ecommended. Theprecolumn is connected directly to the gas sampling valve foron-column injection. The inlet system must be well condi-tioned and evaluated frequently for compatibility with tracequantities of reactive sulfur compounds, such as tert-butylmercaptan.6.1.2 Digital Pressure TransmitterA ca
30、librated stainlesssteel pressure/vacuum transducer with a digital readout may beequipped to allow sampling at different pressures to generatecalibration curves.6.1.3 Column Temperature ProgrammerThe chromato-graph must be capable of linear programmed temperatureoperation over a range from 30 to 200C
31、, in programmed ratesettings of 0.1 to 30C/min. The programming rate must besufficiently reproducible to obtain retention time repeatabilityof 0.05 min (3 s).6.1.4 Carrier and Detector Gas ControlConstant flowcontrol of carrier and detector gases is critical to optimum andconsistent analytical perfo
32、rmance. Control is best provided bythe use of pressure regulators and fixed flow restrictors. Thegas flow rate is measured by any appropriate means and therequired gas flow indicated by the use of a pressure gage. Massflow controllers, capable of maintaining gas flow constant to61 % at the required
33、flow rates also can be used. The supplypressure of the gas delivered to the gas chromatograph must beat least 69 kPa (10 psi) greater than the regulated gas at theinstrument to compensate for the system back pressure. Ingeneral, a supply pressure of 552 kPa (80 psig) will besatisfactory.6.1.5 Detect
34、orA flame photometric detector calibrated inthe sulfur-specific mode is used for this test method. Otherdetectors as mentioned in 4.4 will not be covered in this testmethod. This detector may be obtained from various manufac-turers; however, there are variations in design. The pulsedflame photometri
35、c detector (PFPD) is one of the new FPDdesigns. The pressure and flow rate of the hydrogen and air7Registered trademark. Available from DuPont de Nemours, E. I., gas chromatography; sul-fur compounds, odorantsASTM International takes no position respecting the validity of any patent rights asserted
36、in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the
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38、reful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM Internatio
39、nal, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D 6228 98 (2003)6
