1、Designation: D 5504 08Standard Test Method forDetermination of Sulfur Compounds in Natural Gas andGaseous Fuels by Gas Chromatography andChemiluminescence1This standard is issued under the fixed designation D 5504; the number immediately following the designation indicates the year oforiginal adopti
2、on 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 test method is primarily for the determination ofspeciated volatile s
3、ulfur-containing compounds in high meth-ane content gaseous fuels such as natural gas. It has beensuccessfully applied to other types of gaseous samples includ-ing air, digester, landfill, and refinery fuel gas. The detectionrange for sulfur compounds, reported as picograms sulfur, isten (10) to one
4、 million (1 000 000). This is equivalent to 0.01to 1 000 mg/m3, based upon the analysis ofa1ccsample.1.2 The range of this test method may be extended to higherconcentration by dilution or by selection of a smaller sampleloop.NOTE 1 Dilution will reduce method precision.1.3 This test method does not
5、 purport to identify all sulfurspecies in a sample. Only compounds that are eluted throughthe selected column under the chromatographic conditionschosen are determined. The detector response to sulfur isequimolar for all sulfur compounds within the scope (1.1)ofthis test method. Thus, unidentified c
6、ompounds are determinedwith equal precision to that of identified substances. Totalsulfur content is determined from the total of individuallyquantified components.1.4 The values stated in SI units are standard. The valuesstated in inch-pound units are for information only.1.5 This standard does not
7、 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 limitations prior to use.2. Referenced Documents2.1 ASTM Standards
8、:2D 1072 Test Method for Total Sulfur in Fuel Gases byCombustion and Barium Chloride TitrationD 1945 Test Method for Analysis of Natural Gas by GasChromatographyD 3609 Practice for Calibration Techniques Using Perme-ation TubesD 4468 Test Method for Total Sulfur in Gaseous Fuels byHydrogenolysis and
9、 Rateometric ColorimetryE 594 Practice for Testing Flame Ionization Detectors Usedin Gas or Supercritical Fluid Chromatography3. Summary of Test Method3.1 The analysis of gaseous sulfur compounds is challeng-ing due to the reactivity of these substances. They are difficultto sample and analyze. Idea
10、lly, analysis is performed on-site toeliminate sample deterioration as a factor in analysis. Samplingmust be performed using non-reactive containers, such asSilcosteel3lined vessels, Tedlar4bags with polypropylenefittings or the equivalent. Tedlar4bag samples require protec-tion from light and heat.
11、 Laboratory equipment must be inert orpassivated to ensure reliable results.3.2 A one cc (mL) sample is injected into a gas chromato-graph where it is eluted through a megabore, thick film, methylsilicone liquid phase, open tubular partitioning column or othersuitable column, and separated into its
12、individual constituents.3.3 Sulfur Chemiluminescence DetectionAs sulfur com-pounds elute from the gas chromatographic column, they areprocessed in a flame ionization detector (FID) or a heatedcombustion zone. The products are collected and transferred toa sulfur chemiluminescence detector (SCD). Thi
13、s techniqueprovides a sensitive, selective, linear response to volatile sulfurcompounds and may be used while collecting hydrocarbon andfixed gas data from a FID.3.3.1 Detectors in Series with a SCDA SCD can fre-quently be used in series with other fixed gas and hydrocarbondetectors. However, regula
14、tory bodies may question detectorcompatibility and require demonstration of equivalence be-tween a SCD in a multi-detector system and a SCD operated1This test method is under the jurisdiction ofASTM Committee D03 on GaseousFuels and is the direct responsibility of Subcommittee D03.05 on Determinatio
15、n ofSpecial Constituents of Gaseous Fuels.Current edition approved June 15, 2008. Published July 2008. Originallyapproved in 1994. Last previous edition approved in 2006 as D 5504 01(2006).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at servic
16、eastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Silcosteel is a trademark of Restek Corporation, 110 Benner Circle Bellefonte,PA, 16823.4Tedlar is a trademark of DuPont.1Copyright ASTM International, 100 Barr Harbor Dri
17、ve, PO Box C700, West Conshohocken, PA 19428-2959, United States.using a FID or combustion zone.The user is referred to USEPAMethod 301 for an example of a general equivalence proce-dure.3.3.2 Alternative DetectorsThis test method is written forthe sulfur chemiluminescent detector but other sulfur s
18、pecificdetectors can be used provided they have sufficient sensitivity,respond to all eluted sulfur compounds, do not suffer frominterferences and satisfy quality assurance criteria. Regulatoryagencies may require demonstration of equivalency of alterna-tive detection systems to the SCD.4. Significa
19、nce and Use4.1 Many sources of natural and petroleum gases containsulfur compounds that are odorous, corrosive, and poisonous tocatalysts used in gaseous fuel processing.4.2 Low ppm amounts of sulfur odorants are added tonatural gas and LP gases for safety purposes. Some odorantsare unstable and rea
20、ct to form compounds having lower odorthresholds. Quantitative analysis of these odorized gases en-sures that odorant injection equipment is performing to speci-fication.4.3 Although not intended for application to gases otherthan natural gas and related fuels, this test method has beensuccessfully
21、applied to fuel type gases including refinery,landfill, cogeneration, and sewage digester gas. Refinery,landfill, sewage digester and other related fuel type gasesinherently contain volatile sulfur compounds that are subject tofederal, state, or local control. The methane fraction of thesefuel type
22、gases are occasionally sold to distributors of naturalgas. For these reasons, both regulatory agencies and productionand distribution facilities may require the accurate determina-tion of sulfur to satisfy regulatory, production or distributionrequirements. Fuel gases are also used in energy product
23、ion orare converted to new products using catalysts that are poisonedby excessive sulfur in the feed gas. Industry frequently requiresmeasurement of sulfur in these fuel type gases to protect theircatalyst investments.4.4 Analytical MethodsGas chromatography (GC) iscommonly used in the determination
24、 of fixed gas and organiccomposition of natural gas (Test Method D 1945). OtherstandardASTM methods for the analysis of sulfur in fuel gasesinclude Test Methods D 1072 and D 4468 for total sulfur andTest Methods D 4010 and D 4884 for hydrogen sulfide.5. Apparatus5.1 ChromatographAny gas chromatograp
25、h of standardmanufacture, with hardware necessary for interfacing to achemiluminescence detector and containing all features neces-sary for the intended application(s) can be used. Chromato-graphic parameters must be capable of obtaining retention timerepeatability of 0.05 min (3 s) throughout the s
26、cope of thisanalysis.5.1.1 Sample Inlet SystemA sample inlet system capableof operating continuously at the maximum column temperatureis used. A split/splitless injection system capable of splitlessoperation and split control from 10:1 up to 50:1 may be usedwith capillary columns, or when interferan
27、ts are encountered.An automated gas sampling valve is required for manyapplications. The inlet system must be conditioned or con-structed of inert material and evaluated frequently for compat-ibility with trace quantities of reactive sulfur compounds.5.1.2 Carrier and Detector Gas ControlConstant fl
28、owcontrol of carrier and detector gases is critical for optimum andconsistent analytical performance. Control is achieved by useof pressure regulators and fixed flow restrictors. The gas flowis measured by appropriate means and adjusted. Mass flowcontrollers, capable of maintaining gas flow constant
29、 to 61%at the flow rates necessary for optimal instrument performancecan be used.5.1.3 DetectorSulfur compounds are processed using aflame ionization detector (FID), a heated combustion zone or asimilar device. The products are collected and delivered to asulfur chemiluminescence detector (SCD).5.1.
30、3.1 FIDThe detector must meet or exceed the speci-fications in Table 1 of Practice E 594 while operating withinmanufacturers specifications. The detector must be capable ofoperating at the maximum column temperature. The flow pathfrom the injection system through the column to the FID mustremain at
31、or above the column temperature throughout theanalysis. The FID must allow for the insertion of a SCDsampling probe into the flame without compromising theability of the FID to detect hydrocarbons. Flow rates of air andhydrogen or, alternatively of oxygen and hydrogen, must beoptimized to produce a
32、hydrogen rich flame or combustionzone that is capable of combusting hydrocarbons. This isnecessary to minimize matrix effects. When performing thesimultaneous detection of hydrocarbons is necessary, a FIDand heated combustion zone can be used in series. Zero air isnecessary when performing the simul
33、taneous determination ofsulfur gases and hydrocarbons.5.1.3.2 SCDThe sulfur chemiluminescence detector shallmeet or exceed the following specifications: (1) greater than105linearity, (2) less than 5 pg S/s sensitivity, (3) greater than106selectivity for sulfur compounds over hydrocarbons, (4)noquenc
34、hing of sulfur compound response, and (5) no interfer-ence from co-eluting compounds at the usual GC samplingvolumes.5.1.3.3 Heated Combustion ZoneSulfur compounds elut-ing from the chromatographic column are processed in a heatedhydrogen rich combustion zone or a flame ionization detectorfitted to
35、the end of the column. Products are transferred underreduced pressure to the reaction chamber of a chemilumines-cence detector. An excess of ozone present in the chamberreacts with the sulfur combustion product(s) to liberate blue(480 nm) and ultraviolet light (260 nm).5.1.3.4 SCD operation is based
36、 on the chemiluminescence(light emission) produced by the reaction of ozone with anunidentified sulfur species produced in a combustion zone,flame ionization detector or related device. The chemilumines-cent sulfur species is the subject of on-going research. Theappendix describes two chemiluminesce
37、nce reaction models.The sulfur combustion product(s) and an excess of ozone aredrawn into a low pressure (20 Torr) reaction cell. The ozonereacts to produce blue light (480 nm), oxygen, and otherproducts. A blue sensitive photomultiplier tube detects theemitted light which is then amplified for disp
38、lay or output to adata collection system.D55040825.2 ColumnA variety of columns can be used in thedetermination of sulfur compounds. Typically, a 60 m 3 0.54mm ID fused silica open tubular column containinga5mfilmthickness of bonded methyl silicone liquid phase is used. Theselected column must provi
39、de retention and resolution charac-teristics such as listed in Table 2 and illustrated in Fig. 1. Thecolumn must be inert towards sulfur compounds. The columnmust also demonstrate a sufficiently low liquid phase bleed athigh temperature such that loss of the SCD response is notencountered while oper
40、ating the column at 200C.5.3 Data Acquisition:5.3.1 RecorderA 0 to 1 mV range recording potentiom-eter or equivalent, with a full-scale response time of2sorlesscan be used.5.3.2 IntegratorAn electronic integrating device or com-puter can be used. A dual channel system is necessary forsimultaneous ac
41、quisition of both the FID and SCD signals. Thedevice and software must have the following capabilities:5.3.2.1 Graphic presentation of the chromatogram.5.3.2.2 Digital display of chromatographic peak areas.5.3.2.3 Identification of peaks by retention time or relativeretention time, or both.5.3.2.4 C
42、alculation and use of response factors.5.3.2.5 External standard calculation and data presentation.6. Reagents and MaterialsNOTE 2Warning: Sulfur compounds contained in permeation tubesor compressed gas cylinders may be flammable and harmful or fatal ifingested or inhaled. Permeation tubes and compr
43、essed gas standardsshould only be handled in well ventilated locations away from sparks andflames. Improper handling of compressed gas cylinders containing air,nitrogen or helium can result in explosion. Rapid release of nitrogen orhelium can result in asphyxiation. Compressed air supports combustio
44、n.6.1 Sulfur StandardsAccurate sulfur standards are re-quired for sulfur gas quantitation. Permeation and compressedgas standards should be stable, of high purity, and of thehighest available accuracy.6.1.1 Permeation DevicesSulfur standards can consist ofpermeation tubes, one for each selected sulf
45、ur species gravi-metrically calibrated and certified at a convenient operatingtemperature. With constant temperature, calibration gases cov-ering a wide range of concentration can be generated byvarying and accurately measuring the flow rate of diluent gaspassing over the tubes. These calibration ga
46、ses are used tocalibrate the GC/SCD system.6.1.1.1 Permeation System Temperature ControlPermeation devices are maintained at the calibration tempera-ture within 0.1C.6.1.1.2 Permeation System Flow ControlThe permeationflow system measures diluent gas flow over the permeationtubes within 62 percent.T
47、ABLE 1 Example Retention Times Using 4 Capillary Column(30 m 3 0.32 mm)Conditions as in Table 2Compound Ave. RT min Compound Ave. RT minMethane 1.458 ?S 16.363Ethane 1.730 n-Octane 16.423Ethylene 1.733 ?S 16.425Hydrogen Sulfide 2.053 ?S 16.592Propylene 2.550 ?S 16.692Carbonyl Sulfide 2.586 ?-EtThiop
48、hene 16.983Propane 2.679 ?S 17.183Sulfur Dioxide 2.815 ?S 17.319i-Butane 4.422 ?S 17.631Butene-1 5.263 ?S 17.754n-Butane 5.578q m therefore, responsefactors for all calibration components should be within 5 % ofthe response factor for hydrogen sulfide. Failure to satisfy thiscriteria indicates eithe
49、r calibration standard degradation orfailure of the SCD heated combustion zone, flame ionizationdetector (FID), or related device.8.2.5 Calculate the relative response factor for each sulfurcompound:Fn5 Cn/An! (1)where:Fn= response factor of compound,Cn= concentration of the sulfur compound in the mixture,andAn= peak area of the sulfur compound in the mixture.The response factor (Fn) of each single sulfur compoundshould be within 5 % of Fnfor hydrogen sulfide. Fig. 1provides an example of a typical chromatogram and Table 4shows the data and calibration report
