1、Designation: D7166 10Standard Practice forTotal Sulfur Analyzer Based On-line/At-line for SulfurContent of Gaseous Fuels1This standard is issued under the fixed designation D7166; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、 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 total sulfur fromvolatile sulfur-containing compounds in high metha
3、ne orhydrogen content gaseous fuels using on-line/at-line instru-mentation.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its
4、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:2D1070 Test Methods for Relative Density of Gaseous FuelsD1072 Test Method
5、 for Total Sulfur in Fuel Gases byCombustion and Barium Chloride TitrationD3246 Test Method for Sulfur in Petroleum Gas by Oxida-tive MicrocoulometryD3609 Practice for Calibration Techniques Using Perme-ation TubesD3764 Practice for Validation of the Performance of Pro-cess Stream Analyzer SystemsD4
6、298 Guide for Intercomparing Permeation Tubes to Es-tablish TraceabilityD4468 Test Method for Total Sulfur in Gaseous Fuels byHydrogenolysis and Rateometric ColorimetryD5287 Practice for Automatic Sampling of Gaseous FuelsD5453 Test Method for Determination of Total Sulfur inLight Hydrocarbons, Spar
7、k Ignition Engine Fuel, DieselEngine Fuel, and Engine Oil by Ultraviolet FluorescenceD5503 Practice for Natural Gas Sample-Handling and Con-ditioning Systems for Pipeline InstrumentationD5504 Test Method for Determination of Sulfur Com-pounds in Natural Gas and Gaseous Fuels by Gas Chro-matography a
8、nd ChemiluminescenceD6122 Practice for Validation of the Performance of Mul-tivariate Process Infrared Spectrophotometer Based Ana-lyzer SystemsD6299 Practice for Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System PerformanceD6621 Practice
9、for Performance Testing of ProcessAnalyz-ers for Aromatic Hydrocarbon MaterialsD6667 Test Method for Determination of Total VolatileSulfur in Gaseous Hydrocarbons and Liquefied PetroleumGases by Ultraviolet FluorescenceD6920 Test Method for Total Sulfur in Naphthas, Distil-lates, Reformulated Gasoli
10、nes, Diesels, Biodiesels, andMotor Fuels by Oxidative Combustion and Electrochemi-cal Detection2.2 ISO Standards3ISO 7504 Gas Analysis-Vocabulary3. Terminology3.1 Definitions:3.1.1 at-line instrumentinstrumentation requiring opera-tor interaction that samples gas directly from the pipeline.3.1.2 cal
11、ibration 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.3.1.2.1 DiscussionCalibration Gas Mixtures are the ana-logues of measurement standards in physical metrology (ref-er
12、ence ISO 7504 paragraph 4.1).3.1.3 continuous fuel monitorinstrument that samples gasdirectly from the pipeline on a continuous or semi-continuousbasis.1This practice is under the jurisdiction of ASTM Committee D03 on GaseousFuels and is the direct responsibility of Subcommittee D03.12 on On-Line/At
13、-LineAnalysis of Gaseous Fuels.Current edition approved Jan. 1, 2010. Published February 2010 Originallyapproved in 2005. Last previous edition approved in 2005 as D716605. DOI:10.1520/D7166-10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at s
14、erviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from International Organization for Standardization (ISO), 1, ch. dela Voie-Creuse, Case postale 56, CH-1211, Geneva 20, Switzerland, http:/www.iso.ch.1Copy
15、right ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.4 direct samplingsampling where there is no directconnection between the medium to be sampled and theanalytical unit.3.1.5 in-line instrumentinstrument with an active elementinstalled in
16、 a pipeline, which is used to measure pipelinecontents or conditions.3.1.6 on-line instrumentinstrument that samples gas di-rectly from a pipeline, but is installed externally.3.1.7 reference gas mixture, na certified gas mixture withknown composition used as a reference standard from whichother com
17、positional data are derived.3.1.7.1 DiscussionReference Gas Mixtures are the ana-logues of measurement standards of reference standards (ref-erence ISO 7504 paragraph 4.1.1).3.1.8 total reduced sulfur (TRS)concentration summationof all volatile sulfur species with a 2 sulfur oxidation number,excludi
18、ng sulfur dioxide, sulfones and other inorganic sulfurcompounds.3.1.9 total sulfurconcentration summation of all volatilesulfur species in a sample.3.1.10 volatilemolecular characteristic wherein the sulfurspecie exists in the gas phase at the operating conditions of theprocess or pipeline.4. Summar
19、y of Practice4.1 A representative sample of the gaseous fuel is extractedfrom a process pipe or pipeline and is transferred in a timelymanner through an appropriately designed sampling system tothe inlet of a total sulfur analyzer. The sample is conditionedwith a minimum, preferably negligible, impa
20、ct on the sulfurcontent. A precisely measured volume of sample is eitherinjected, or allowed to flow continuously, either directly intothe analyzer or into a carrier gas, as required by the analyzer.Some total sulfur analyzer systems are configured such thatsample gas flows directly into the analyze
21、r detection system.Excess process or pipeline sample is vented to atmosphere, toflare or to the process stream dependant upon application andregulatory requirements.4.2 Sample containing carrier gas is fed to a furnaceoperating at an elevated temperature where sulfur compoundsare converted into dete
22、ctable species. The conversion reactionmay be oxidative or reductive and may require the introductionof additional carrier or other supply gases.4.3 Furnace exit gasses are conditioned as required withrespect to temperature and water content and are introducedinto the detector where quantification o
23、f the total sulfur contentoccurs.4.4 Calibration, maintenance, quality assurance and perfor-mance protocols provide a means to validate the analyzeroperation and the generated results.5. Significance and Use5.1 On-line, at-line, in-line and other near-real time moni-toring systems that measure fuel
24、gas characteristics such as thetotal sulfur content are prevalent in the natural gas and fuel gasindustries. The installation and operation of particular systemsvary on the specific objectives, contractual obligations, processtype, regulatory requirements, and internal performance re-quirements need
25、ed by the user. This protocol is intended toprovide guidelines for standardized start-up procedures, oper-ating procedures, and quality assurance practices for on-line,at-line, in-line and other near-real time total sulfur monitoringsystems.6. Apparatus6.1 InstrumentAny instrument of standard manufa
26、cture,with hardware necessary for interfacing to a natural gas,hydrogen or other fuel gas pipeline and containing all thefeatures necessary for the intended application(s) can be used.6.1.1 Specific Sulfur Specie Detection SystemsThe oper-ating parameters employed generally must be capable ofconvert
27、ing all of the volatile sulfur species in the sample intoa single detectable species such as sulfur dioxide or hydrogensulfide. Instrumentation must satisfy or exceed other analyticperformance characteristics for accuracy and precision for theintended application without encountering unacceptable in
28、ter-ference or bias. In addition, components in contact with samplestreams such as tubing and valving must be constructed ofsuitable inert, or passivated, materials to ensure constituents inthe fuel stream do not degrade these components or alter thecomposition of the sampled gas.6.2 Sample Probes/S
29、ample ExtractionThe location andorientation of sampling components are critical for ensuringthat a representative sample is analyzed. The locations andorientation of sampling components should be selected basedupon sound analytic and engineering considerations. Samplingpractices for gaseous fuels ca
30、n be found in Practice D5287.6.3 Sample Inlet System The siting and installation of anat-line or on-line monitor is critical for collecting representa-tive information on sulfur content. Factors that should beconsidered in siting an instrument include ease of calibration,ease of access for repair or
31、 maintenance, sample uniformity atthe sampling point, appropriateness of samples from a sam-pling location, ambient conditions, and of course safety issues.An automated gas sampling valve is required in many appli-cations. All sampling system components in contact with thefuel stream must be constru
32、cted of inert or passivated materi-als. Care should be taken to ensure that the extracted sample ismaintained as a particulate and condensate free gas. Heating atthe point of pressure reduction or along the sample line to theanalyzer and the use of a filter may be required to ensure thatthe sample i
33、s maintained in the gas phase. The need for heattracing and the extent to which it is required will be site andapplication specific. In general, considerations impacting heattracing decisions include sample compositions and the ex-pected variations, ambient temperature fluctuations, operatingpressur
34、es, anticipated pressure differentials in sample systemcomponents, and safety considerations. Sample filtrationshould be utilized as required to remove particulate matterfrom the extracted sample. The sampling frequency relative tothe process bandwidth is critical to ensuring that the reportedanalyt
35、ical results adequately represent the process being moni-tored. The Nyquist-Shannon sampling criterion of a samplingfrequency that exceeds twice the process bandwidth can beused to establish a minimum analytical cycle time. Samplehandling and conditioning system practices can be found inPractice D55
36、03.D7166 1026.3.1 Carrier and Detector 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 as well asrotameters. Temperature control is generally vital
37、for ensuringconsistent operation of these devices. The gas flow is measuredby appropriate means and adjusted as necessary. Mass flowcontrollers, capable of maintaining a gas flow constant towithin 61 % at the flow rates necessary for optimal instrumentperformance are typically used.6.3.2 DetectorsCo
38、mmon detectors used for total sulfurdeterminations include chemiluminescence (Test MethodD5504), microcoulometry (Test Method D3246), electrochemi-cal (Test Method D6920), lead acetate (Test Method D4468),titration, such as barium chloride (Test Method D1072),ultra-violet fluorescence (Test Methods
39、D5453 and D6667),both continuous and pulsed. Other detectors can be usedprovided they have appropriate linearity, sensitivity, and selec-tivity for the selected application. In selecting a detector, theuser should consider the linearity, sensitivity, and selectivity ofparticular detection systems pr
40、ior to installation. The usershould also consider interference from substances in the gasstream that could result in inaccurate sulfur gas measurementdue to effects such as quenching.6.4 Data AcquisitionData acquisition and storage can beaccomplished using a number of devices and media. Followingare
41、 some examples.6.4.1 Recorder A 0 to 1 mV range recording potentiom-eter or equivalent can be used.6.4.2 CommunicationsEfficient communications betweenthe analyzer and the host depend on resolving any and allinterface issues. Signals to and from the host are typicallyoptically isolated from each oth
42、er.7. Reagents and MaterialsNOTE 1Warning: Compressed gas standards should only be handledin well ventilated locations away from sparks and flames. Improperhandling of compressed gas cylinders containing calibration standards, air,nitrogen, hydrogen, argon or helium can result in explosion. Rapid re
43、leaseof nitrogen or helium can result in asphyxiation. Compressed air supportscombustion. Sulfur species and radiation sources can be toxic.7.1 StandardsAccurate sulfur standards are required forthe determination of total sulfur. Standards are available asprepared standards in the form of a compress
44、ed gas or as apreparable standard in the form of a permeation tube calibra-tion device.7.2 Prepared StandardsCompressed gas standards shouldbe stable, of the highest available accuracy and purity and usedin accordance with the manufacturers recommendations. Thematrix components in the reference stan
45、dard can be represen-tative of the monitored gas. Alternatively, a simplified matrixcan be used if the analyzer can be calibrated in accordance withthe manufacturers specifications. Sulfur concentrations aredependent on the detector linearity and are typically selectedbetween one half and twice thei
46、r expected concentration in themonitored gas. Alternatively, a critical value of sulfur concen-tration , such as an alarm limit, can be used to identlify thedesired total sulfur concentration of the standard. Using asulfur specie that differs from what the detector sees allows fora total analyzer sy
47、stem performance check. Standards must bemaintained within the temperature range specified by themanufacturer to ensure accuracy and stability.7.3 Permeation DevicesPermeation devices contain analiquot of a specific compound that continuously diffuses at adetermined rate through a permeable medium.
48、A dry inertcarrier gas flows at a constant rate across the medium at aconstant temperature consistent with the manufacturers rec-ommendations to create a calibration gas that then flows to theanalyzer. Proper storage, in accordance with the manufactur-ers recommendations, is required to prevent dama
49、ge to themembrane. A sufficiently long equilibration time is requiredwhen the permeation device temperature is changed to ensurethe reestablishment of a constant permeation rate. Calibrationdevices using permeation tubes contain a temperature con-trolled oven and employ flow control to maintain a constantdiluent flow rate. Practice D3609 and Guide D4298 containadditional information on permeation tubes.8. Equipment Siting and Installation8.1 Asample inlet system capable of operating continuouslyand delivering a gas phase sample to the analyzer is necess
