1、Designation: D7314 10 (Reapproved 2015)Standard Practice forDetermination of the Heating Value of Gaseous Fuels usingCalorimetry and On-line/At-line Sampling1This standard is issued under the fixed designation D7314; the number immediately following the designation indicates the year oforiginal adop
2、tion 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 practice is for the determination of the heatingvalue measurement o
3、f gaseous fuels using a calorimeter.Heating value determination of sample gasses containing watervapor will require vapor phase moisture measurements of thepre-combustion sample gas as well as the non-condensedgasses exiting the calorimeter. Instruments equipped withappropriate conditioners and algo
4、rithms may provide heatingvalue results on a net or gross and dry or wet basis.1.2 This practice is applicable to at-line and in-line instru-ments that are operated from time to time on a continuousbasis.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement a
5、re included in thisstandard.1.4 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 limitations
6、prior to use.2. Referenced Documents2.1 ASTM Standards:2D1070 Test Methods for Relative Density of Gaseous FuelsD1826 Test Method for Calorific (Heating) Value of Gases inNatural Gas Range by Continuous Recording CalorimeterD3588 Practice for Calculating Heat Value, CompressibilityFactor, and Relati
7、ve Density of Gaseous FuelsD3764 Practice for Validation of the Performance of ProcessStream Analyzer SystemsD4150 Terminology Relating to Gaseous FuelsD4891 Test Method for Heating Value of Gases in NaturalGas and Flare Gases Range by Stoichiometric Combus-tionD5287 Practice for Automatic Sampling
8、of Gaseous FuelsD5503 Practice for Natural Gas Sample-Handling and Con-ditioning Systems for Pipeline InstrumentationD6122 Practice for Validation of the Performance of Multi-variate Online, At-Line, and Laboratory Infrared Spectro-photometer Based Analyzer SystemsD6299 Practice for Applying Statist
9、ical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System PerformanceD6621 Practice for Performance Testing of Process Analyz-ers for Aromatic Hydrocarbon MaterialsD7164 Practice for On-line/At-line Heating Value Determi-nation of Gaseous Fuels by Gas Chromatogra
10、phy2.2 ISO Standards:3ISO 14532 Natural gasVocabularyISO 7504 Gas analysisVocabulary3. Terminology3.1 Definitions:3.1.1 at-line instrument, nSee Terminology D4150, Sec-tion 3.3.1.2 auto-verification, nan automated means of introduc-ing Calibration Gas Mixtures or Reference Gas Mixtures intoan analyz
11、er for the purposes of verifying the analyzer responsewithout making any adjustments to the calibration parametersof the analyzer.3.1.3 bypass line, nLine ultimately vented to the atmo-sphere that is used where it is impractical to provide a sufficientpressure differential.3.1.3.1 DiscussionThe flow
12、rate and pressure loss in theopen-ended line needs to be controlled so as to ensure that thesample accuracy is not affected from any cooling and conden-sation or both (reference ISO 14532 paragraph 2.3.2.9).1This practice is under the jurisdiction of ASTM Committee D03 on GaseousFuels and is the dir
13、ect responsibility of Subcommittee D03.12 on On-Line/At-LineAnalysis of Gaseous Fuels.Current edition approved June 1, 2015. Published July 2015. Originally approvedin 2008. Last previous edition approved in 2010 as D7314-10. DOI: 10.1520/D7314-10R15.2For referenced ASTM standards, visit the ASTM we
14、bsite, 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 Standardization (ISO), 1, ch. dela Voie-Creuse, Case postale 56
15、, 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 States13.1.4 calibration gas mixture, na certified gas mixturewith known composition used for the calibration of a measur-ing instrument or f
16、or the validation of a measurement or gasanalytical method.3.1.4.1 DiscussionCalibration Gas Mixtures are the ana-logues of measurement standards in physical metrology (ref-erence ISO 7504 paragraph 4.1)3.1.5 calorimeter, nSee Terminology D4150, Section 3.3.1.6 continuous fuel monitor, nan instrumen
17、t thatsamples gas directly from a source continuously and providesan analytical result on a continuous or semi-continuous basis.3.1.7 direct sampling, adjsampling where there is a directconnection between the sample source and the analytical unit,that is, in-line or on-line instrument.3.1.8 dry gas,
18、 nSee Terminology D4150, Section 3.3.1.9 fast loop/hot loop, nBypass loop that returnssampled gas to the process line in a closed configuration andused for environmental and safety considerations.3.1.9.1 DiscussionThe loop requires a pressure differen-tial from the collection point to the discharge
19、point so as toensure a constant and steady flowrate through the samplingequipment located in the loop (reference ISO 14532 paragraph2.3.2.8)3.1.10 gross heating value (also called higher heatingvalue), nSee Terminology D4150, Section 3.3.1.11 heating value, nthe amount of energy per volumetransferre
20、d as heat from the complete, ideal combustion of thegas at standard temperature.3.1.12 in-line instrument, nSee Terminology D4150, Sec-tion 3.3.1.13 net heating value (also called lower heating value),nSee Section 3 entitled Terminology, of D4150.3.1.14 on-line instrument, nSee Terminology D4150, Se
21、c-tion 3.3.1.15 reference gas mixture, na certified gas mixture withknown composition used as a reference standard from whichother compositional data are derived.3.1.15.1 Discussion Reference Gas Mixtures are the ana-logues of reference standards (ISO 7504 paragraph 4.1.1)3.1.16 wet gas, nSee Termin
22、ology D4150, Section 3.3.2 Acronyms:3.2.1 SOP, nStandard Operating Procedure.3.2.2 QA, nQuality Assurance.4. Summary of Practice4.1 A representative sample of the gaseous fuel is extractedfrom a process pipe, a pipeline, or other gaseous fuel streamand is transferred to an analyzer sampling system.
23、Afterconditioning that maintains the sample integrity, the sample isintroduced into a calorimeter. Excess extracted process orsample gas is vented to the atmosphere, a flare header, or isreturned to the process in accordance with applicable economicand environmental requirements and regulations. Pos
24、t-combustion gasses from the calorimeter are typically vented tothe atmosphere.4.2 The heating value is calculated based upon the instru-ments response to changes in the heating value of the samplegas using an algorithm.4.3 Calibration (7.1), maintenance (Section 10), and perfor-mance (Section 9) pr
25、otocols provide a means to validate andassess operation of the analyzer.5. Significance and Use5.1 On-line, at-line, in-line and other near-real time moni-toring systems that measure fuel gas characteristics such asheating value are prevalent in various gaseous fuel industriesand in industries eithe
26、r producing or using gaseous fuel in theirindustrial processes. The installation and operation of particu-lar systems vary depending on process type, regulatoryrequirements, and the users objectives and performance re-quirements. This practice is intended to provide guidance forstandardized start-up
27、 procedures, operating procedures, andquality assurance practices for calorimeter based on-line,at-line, in-line and other near-real time heating value monitor-ing systems. Users employing gas chromatographic basedinstrumentation for measurement of gaseous fuel heating valueare referred to Practice
28、D7164.6. Apparatus6.1 InstrumentAny instrument of standard manufacture,with hardware necessary for interfacing to a fuel gas pipelineand containing all the features necessary for the intendedapplication(s) can be used.6.1.1 Combustion SystemOperating parameters employedmust be capable of converting
29、all of the volatile combustiblechemical species in the sample into carbon dioxide, water,nitrogen, nitrogen dioxide, and/or sulfur dioxide, using a dry,hydrocarbon-free oxidant which is typically air. A change ofless than or equal to 1,000 ppm/wt in the moisture content ofinstrument air between calo
30、rimeter calibrations is acceptable tomaintain a statistically insignificant 6 0.1% heating valueaccuracy as denoted in Practice D4891. The less than 1,000ppm/wt moisture content control value is easily achieved usingdesiccant or refrigerant air dryers when the air dryers aremaintained according to t
31、he manufacturers recommendations.Instrumentation must satisfy or exceed analytic performancecharacteristics for accuracy and precision for the intendedapplication without encountering unacceptable interference orbias. In addition, components in contact with sample streamssuch as tubing and valving m
32、ust be constructed of suitable inertor passivated materials to ensure that the composition of thesampled gas is not altered.6.2 Sample Probes/Sample ExtractionThe location andorientation of sampling components are critical for ensuringthat a representative sample is analyzed. The locations andorient
33、ation of sampling components should be selected basedupon sound analytic and engineering considerations. Samplingpractices for gaseous fuels can be found in Practice D5287.6.3 Sample Inlet SystemAn automated gas sampling valveis required in many applications. All sampling system compo-nents in conta
34、ct with the fuel stream must be constructed ofinert or passivated materials. Care should be taken to ensurethat the extracted sample is maintained in a single cleanD7314 10 (2015)2gaseous phase. The addition of heat at the point of pressurereduction or along the sample line to the analyzer may bereq
35、uired to ensure that the sample is maintained in the gasphase. The need for heat tracing and the extent to which it isrequired will be site specific. In general, considerations im-pacting heat tracing decisions include sample compositions andthe expected variations, ambient temperature fluctuations,
36、operating pressures, and anticipated pressure differentials insample system components. Sample filtration should be uti-lized as required to remove particulate matter from the ex-tracted sample.6.3.1 Combustion Air, Sample, and Carrier Gas ControlConstant flow control of combustion air, sample gas,
37、andcarrier gas, if required by the measurement application, isnecessary for optimum and consistent analytical performance.Control is typically achieved by use of pressure regulators andfixed flow restrictors. Ambient, combustion air, sample, andcarrier gas temperature control is generally vital for
38、ensuringconsistent operation of flow control devices. The gas flow ismeasured and verified by appropriate means and adjusted asnecessary.6.3.2 DetectorsCommon calorimetry heating value detec-tion systems include stoichiometric combustion (Test MethodD4891), continuous recording calorimeters (Test Me
39、thodD1826), non-stoichiometric combustion, and residual oxygendetection calorimeters. Other detectors can be used providedthey have appropriate linearity, accuracy, sensitivity and mea-surement range for the selected application. In selecting adetector, the user should consider the linearity and sen
40、sitivityof a particular detection system prior to installation. The usershould also consider potential sample compositional effectsthat may influence the reported heating value.6.4 Data AcquisitionData acquisition and storage can beaccomplished using a number of devices and media. Followingare some
41、examples:6.4.1 RecorderA 0 to 1 millivolt or a 4-20 milliamp rangerecording potentiometer or equivalent, with a full-scale re-sponse time of 2 s or less can be used mounted locally orremotely.6.4.2 Communications SystemsEfficient communicationsbetween the analyzer and the host depend on resolving an
42、y andall interface issues. Signals to and from the host are typicallyisolated from each other in an appropriate manner.7. Reagents and Materials7.1 WarningCompressed gas standards should only behandled in well ventilated locations away from sparks andflames. Improper handling of compressed gas cylin
43、ders con-taining calibration standards or air can result in explosion.Compressed air supports combustion.7.1.1 StandardsComponents in the Calibration Gas Mix-ture should be representative of the monitored gas. The heatingvalue is either determined instrumentally or is calculated usinga certified gas
44、 composition of the standard. Practice D3588 orother methods as required for regulatory purposes can be usedto calculate the heating value of a gas mixture. Other heatingvalue calculational algorithms can be used so long as allinterested parties are advised of and are in agreement with thecalculatio
45、nal methodology employed, or both. Methods relatedto determining the relative density of gaseous fuels can befound in Practice D1070. Mixtures of major components aretypically specified to achieve the desired heating value. Aminimum of major representative components is frequentlyused. The number of
46、 components used is frequently minimizedfor economical reasons and to reduce the probability of errorduring the preparation of the Calibration Gas Mixture. In orderto ensure their accuracy and stability by preventing condensa-tion and degradation, Calibration Gas Mixtures must be main-tained within
47、the temperature range specified by the manufac-turer. If there is any doubt concerning the validity of theCalibration Gas Mixture, a Reference Gas Mixture should beused to verify the validity of the Calibration Gas Mixture.8. Equipment Siting and Installation8.1 The siting and installation of an at-
48、line or on-linemonitor is critical for collecting representative information onheating value content. Factors that should be considered insiting an instrument include hazardous area rating, ease ofcalibration, ease of access for repair or maintenance, sampleuniformity at the sampling point, appropri
49、ateness of samplesfrom a sampling location, ambient conditions, and of coursesafety issues. A sample inlet system capable of operatingcontinuously at or above the maximum operating sampletemperature is necessary. The location of the sample inlet to theanalyzer relative to the sample extraction point is critical toobtaining timely analytical results. Ideally, the analyzer isclose-coupled to the sample extraction point and there is aninsignificant sampling lag time. Normally, the analyzer ismounted at some distance away from the sample extractionpo
