1、Designation: D7165 10 (Reapproved 2015)Standard Practice forGas Chromatograph Based On-line/At-line Analysis forSulfur Content of Gaseous Fuels1This standard is issued under the fixed designation D7165; the number immediately following the designation indicates the year oforiginal adoption or, in th
2、e 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 practice is for the determination of volatilesulfur-containing compounds in high
3、methane content gaseousfuels such as natural gas using on-line/at-line instrumentation,and continuous fuel monitors (CFMS). It has been successfullyapplied to other types of gaseous samples including air,digester, landfill, and refinery fuel gas. The detection range forsulfur compounds, reported as
4、picograms sulfur, based uponthe analysis ofa1ccsample, is one hundred (100) to onemillion (1,000,000). This is equivalent to 0.1 to 1,000 mg/m3.1.2 This practice does not purport to measure all sulfurspecies in a sample. Only volatile compounds that are trans-ported to an instrument under the measur
5、ement conditionsselected are measured.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.4 This practice does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the u
6、ser of this practice 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:2D1072 Test Method for Total Sulfur in Fuel Gases byCombustion and Barium Chloride TitrationD1945 Test Method f
7、or Analysis of Natural Gas by GasChromatographyD3606 Test Method for Determination of Benzene andToluene in Finished Motor and Aviation Gasoline by GasChromatographyD3764 Practice for Validation of the Performance of ProcessStream Analyzer SystemsD4084 Test Method for Analysis of Hydrogen Sulfide in
8、Gaseous Fuels (Lead Acetate Reaction Rate Method)D4468 Test Method for Total Sulfur in Gaseous Fuels byHydrogenolysis and Rateometric ColorimetryD4626 Practice for Calculation of Gas ChromatographicResponse FactorsD4810 Test Method for Hydrogen Sulfide in Natural GasUsing Length-of-Stain Detector Tu
9、besD5504 Test Method for Determination of Sulfur Compoundsin Natural Gas and Gaseous Fuels by Gas Chromatogra-phy and ChemiluminescenceD6621 Practice for Performance Testing of Process Analyz-ers for Aromatic Hydrocarbon MaterialsD6122 Practice for Validation of the Performance of Multi-variate Onli
10、ne, At-Line, and Laboratory Infrared Spectro-photometer Based Analyzer SystemsD6228 Test Method for Determination of Sulfur Compoundsin Natural Gas and Gaseous Fuels by Gas Chromatogra-phy and Flame Photometric DetectionE594 Practice for Testing Flame Ionization Detectors Usedin Gas or Supercritical
11、 Fluid Chromatography2.2 ISO Standards3ISO 7504 Gas Analysis-Vocabulary3. Terminology3.1 Definitions:3.1.1 calibration gas mixture, na certified gas mixturewith known composition used for the calibration of a measur-ing instrument or for the validation of a measurement or gasanalytical method.3.1.1.
12、1 DiscussionCalibration Gas Mixtures are the ana-logues of measurement standards in physical metrology (ref-erence ISO 7504 paragraph 4.1).3.1.2 direct samplingSampling where there is no directconnection between the medium to be sampled and theanalytical unit.1This practice is under the jurisdiction
13、 of ASTM Committee D03 on GaseousFuels and is the direct responsibility of Subcommittee D03.12 on On-Line/At-LineAnalysis of Gaseous Fuels.Current edition approved June 1, 2015. Published July 2015 Originally approvedin 2006. Last previous edition approved in 2010 as D716510. DOI: 10.1520/D7165-10R1
14、5.2For referenced 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 International Organization for Standardizat
15、ion (ISO), 1, ch. dela Voie-Creuse, Case postale 56, CH-1211, Geneva 20, Switzerland, http:/www.iso.ch.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.3 in-line instrumentInstrument whose active elementis installed in the pipeline
16、 and measures at pipeline conditions.3.1.4 on-line instrumentAutomated instrument thatsamples gas directly from the pipeline, but is installed exter-nally.3.1.5 at-line instrumentinstrument requiring operator in-teraction to sample gas directly from the pipeline.3.1.6 continuous fuel monitor (CFM)In
17、strument thatsamples gas directly from the pipeline on a continuous orsemi-continuous basis.3.1.7 total reduced sulfur (TRS)Summation of sulfur spe-cies where the sulfur oxidation number is 2, excluding sulfurdioxide, sulfones, and other inorganic sulfur compounds. Thisincludes but is not limited to
18、 mercaptans, sulfides, and disul-fides.3.1.8 near-real time monitoring systemsMonitoring sys-tem where measurement occurs soon after sample flow throughthe system or soon after sample extraction. The definition of anear real time monitoring system can be application specific.3.2 reference gas mixtur
19、e, na certified gas mixture withknown composition used as a reference standard from whichother compositional data are derived.3.2.1 DiscussionReference Gas Mixtures are the ana-logues of measurement standards of reference standards (ref-erence ISO 7504 paragraph 4.1.1).4. Summary of Practice4.1 A re
20、presentative sample of the gaseous fuel is extractedfrom a process pipe or pipeline and is transferred in a timelymanner to an analyzer inlet system. The sample is conditionedwith minimum impact on sulfur content. A precisely measuredvolume of sample is injected into the analyzer. Excess processor p
21、ipeline sample is vented or is returned to the process streamdependant upon application and regulatory requirements.4.2 Sample containing carrier gas is fed to a gas chromato-graph where the components are separated using either apacked or capillary column. Measurement is performed using asuitable s
22、ulfur detection system.4.3 Calibration, precision, calibration error, performanceaudit tests, maintenance methodology and miscellaneous qual-ity assurance procedures are conducted to determine analyzerperformance characteristics and validate both the operation andthe quality of generated results.5.
23、Significance and Use5.1 On-line, at-line, in-line, CFMS, and other near-real timemonitoring systems that measure fuel gas characteristics, suchas the sulfur content, are prevalent in the natural gas and fuelgas industries. The installation and operation of particularsystems vary on the specific obje
24、ctives, contractual obligations,process type, regulatory requirements, and internal perfor-mance requirements needed by the user. This standard isintended to provide guidelines for standardized start-upprocedures, operating procedures, and quality assurance prac-tices for on-line, at-line, in-line,
25、CFMS, and other near-realtime gas chromatographic based sulfur monitoring systemsused to determine fuel gas sulfur content. For measurement ofgaseous fuel properties using laboratory based methods theuser is referred to Test Methods D1072, D1945, D4084,D4468, D4810 and Practices D4626, E594.6. Appar
26、atus6.1 InstrumentAny gas chromatographic based instrumentof standard manufacture, with hardware necessary for interfac-ing to a natural gas or other fuel gas pipeline and containing allfeatures necessary for the intended application(s) can be used.6.1.1 The chromatographic parameters must be capabl
27、e ofobtaining retention time repeatability of 0.05 min. (3 sec.).Instrumentation must meet the performance characteristics forrepeatability and precision without encountering unacceptableinterference or bias. The components coming in contact withsample, such as tubing and valving, must be passivated
28、 orconstructed of inert materials to ensure an accurate sulfur gasmeasurement.6.2 Sample Inlet SystemA sample inlet system capable ofoperating continuously above the maximum column tempera-ture is necessary. A variety of sample inlet configurations canbe used including but not limited to on-column s
29、ystems andsplit/splitless injection system capable of splitless operationand split control from 10:1 up to 50:1. An automated gassampling valve is required for many applications. The inletsystem must be constructed of inert material and evaluatedfrequently for compatibility with reactive sulfur comp
30、ounds.The sampling inlet system is heated as necessary so as toprevent condensation.All wetted sampling system componentsmust be constructed of inert or passivated materials. Sampledelivered to the inlet system should be in the gas phase free ofparticulate or fluidic matter.6.2.1 Carrier and Detecto
31、r Gas ControlConstant flowcontrol 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, as required, tothe desired value. Mass
32、 flow controllers, capable of maintain-ing a gas flow constant to within 6 1 % at the flow ratesnecessary for optimal instrument performance can be used.6.2.2 DetectorSulfur compounds can be measured using avariety of detectors including but not limited to: sulfurchemiluminescence, flame photometric
33、, electrochemical cell,oxidative cell and reductive cells. In selecting a detector, theuser should consider the linearity, sensitivity, and selectivity ofparticular detection systems prior to installation. The usershould also consider interference from substances in the gasstream that could result i
34、n inaccurate sulfur gas measurementdue to effects such as quenching.6.3 ColumnsA variety of columns can be used to separatethe sulfur compounds in the sample. Typically, a 60 m 0.53mm ID fused silica open tubular column containinga5mfilmthickness of bonded methyl silicone liquid phase is used. These
35、lected column must provide retention and resolution charac-teristics that satisfy the intended application. The column mustbe inert towards sulfur compounds. The column must alsodemonstrate a sufficiently low liquid phase bleed at highD7165 10 (2015)2temperature such that a loss of the instrument re
36、sponse is notencountered while operating the column at elevated tempera-tures.6.4 Data AcquisitionData acquisition and storage can beaccomplished using a number of devices and media. Followingare some examples.6.4.1 RecorderAs an example, a 0 to 1 mV range record-ing potentiometer or equivalent, wit
37、h a full-scale response timeof2sorless can be used. A 4-20 mA range recorder can alsobe used.6.4.2 IntegratorAn electronic integrating device or com-puter can be used. For GC based systems, it is suggested thatthe device and software have the following capabilities:6.4.2.1 Graphic presentation of ch
38、romatograms.6.4.2.2 Digital display of chromatographic peak areas.6.4.2.3 Identification of peaks by retention time or relativeretention time, or both.6.4.2.4 Calculation and use of response factors.6.4.2.5 External standard calculation and data presentation.6.4.3 Distributed Control Systems (DCS)De
39、pending onthe site requirements, the analytical results are sometimes fedto a distributed control system. The information is then used tomake the appropriate adjustments to the process. Signal isola-tion between the analyzer and the distributed control networkis most often required. Communications p
40、rotocols with theDCS will dictate the required signal output requirements forthe analyzer.6.4.4 Data Management SystemsData management sys-tems or other data and data processing repositories are some-times used to collect and process the results from a widevariety of instrumentation at a single faci
41、lity. The informationis then available for rapid dissemination within the organiza-tion of the operating facility. Communications protocols withthe data management system will dictate the required signaloutput requirements for the analyzer.7. Reagents and MaterialsNOTE 1Warning: Sulfur compounds con
42、tained in permeation tubesor compressed gas cylinders may be flammable and harmful or fatal ifingested or inhaled. Permeation tubes, which emit their contentscontinuously, and compressed gas standards should only be handled inwell ventilated locations away from sparks and flames. Improper handlingof
43、 compressed gas cylinders containing air, hydrogen, argon, nitrogen orhelium can result in an explosion or in creating oxygen deficientatmospheres. Rapid release of argon, nitrogen or helium can result inasphyxiation. Compressed air supports combustion.7.1 Sulfur StandardsAccurate sulfur standards a
44、re re-quired for the quantitation of the sulfur content of natural gas.Permeation and compressed gas standards should be stable,and of the highest available accuracy and purity.7.1.1 Permeation DevicesSulfur standards can be pro-duced on demand using permeation tubes, one for eachselected sulfur spe
45、cies, gravimetrically calibrated and certifiedat a convenient operating temperature. With constanttemperature, calibration gases covering a wide range of con-centration can be generated by varying and accurately measur-ing the flow rate of diluent gas passing over the tubes.Permeation devices delive
46、ring calibrant at a known high puritymust be used since contaminants will adversely impact thecalculation of analyte concentration due to error in permeationrate calculated from differential weight measurements of thesedevices. It is suggested that certified permeation devices beused whenever availa
47、ble.7.1.1.1 Permeation System Temperature ControlPermeation devices are maintained at the calibration tempera-ture within 0.1 C.7.1.1.2 Permeation System Flow ControlThe permeationflow system measures diluent gas flow over the permeationtubes within 62 percent.7.1.1.3 Permeation tube emission rates
48、are expressed inunits of mass of the emitted sulfur compound contained insideper unit time, i.e. nanograms of methyl mercaptan per minute.The sulfur emission rate is calculated knowing the molecularformula of the sulfur compound used in the permeation tube.7.1.1.4 Permeation tubes are inspected and
49、weighed to thenearest 0.01 mg on at least a monthly basis using a balancecalibrated against NIST traceable “S” class weights or theequivalent. Analyte concentration is calculated by weight lossand dilution gas flow rate as per Practice D3606. These devicesare discarded when the liquid contents are reduced to less thanten (10) percent of the initial volume or when the permeationsurface is unusually discolored or otherwise compromised.7.1.1.5 Permeation tubes must be stored in accordance withthe manufacturers recommendation. Improper storage canresult i
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