1、Designation: D3588 98 (Reapproved 2017)Standard Practice forCalculating Heat Value, Compressibility Factor, and RelativeDensity of Gaseous Fuels1This standard is issued under the fixed designation D3588; the number immediately following the designation indicates the year oforiginal adoption or, in t
2、he 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 covers procedures for calculating heatingvalue, relative density, and c
3、ompressibility factor at baseconditions (14.696 psia and 60F (15.6C) for natural gasmixtures from compositional analysis.2It applies to all com-mon types of utility gaseous fuels, for example, dry natural gas,reformed gas, oil gas (both high and low Btu), propane-air,carbureted water gas, coke oven
4、gas, and retort coal gas, forwhich suitable methods of analysis as described in Section 6are available. Calculation procedures for other base conditionsare given.1.2 The values stated in inch-pound units are to be regardedas the standard. The SI units given in parentheses are forinformation only.1.3
5、 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 prior to use.1.4 This internati
6、onal standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Commi
7、ttee.2. Referenced Documents2.1 ASTM Standards:3D1717 Test Method for Test for Analysis of CommericalButane-Butene Mixtures and Isolutylene by Gas Chroma-tography (Withdrawn 1984)4D1945 Test Method for Analysis of Natural Gas by GasChromatographyD1946 Practice for Analysis of Reformed Gas by GasChro
8、matographyD2163 Test Method for Determination of Hydrocarbons inLiquefied Petroleum (LP) Gases and Propane/PropeneMixtures by Gas ChromatographyD2650 Test Method for Chemical Composition of Gases byMass Spectrometry2.2 GPA Standards:GPA 2145 Physical Constants for the Paraffin Hydrocarbonsand Other
9、Components in Natural Gas5GPA Standard 2166 Methods of Obtaining Natural GasSamples for Analysis by Gas Chromatography5GPA 2172 Calculation of Gross Heating Value, RelativeDensity, and Compressibility Factor for Natural GasMixtures from Compositional Analysis5,6GPAStandard 2261 Method ofAnalysis for
10、 Natural Gas andSimilar Gaseous Mixtures by Gas Chromatography5GPA Technical Publication TP-17 Table of Physical Proper-ties of Hydrocarbons for Extended Analysis of NaturalGases5GPSA Data Book, Fig. 23-2, Physical Constants52.3 TRC Document:TRC Thermodynamic TablesHydrocarbons71This practice is und
11、er the jurisdiction of ASTM Committee D03 on GaseousFuels and is the direct responsibility of Subcommittee D03.03 on Determination ofHeating Value and Relative Density of Gaseous Fuels.Current edition approved April 1, 2017. Published April 2017. Originallyapproved in 1998. Last previous edition app
12、roved in 2011 as D3588 98(2011).DOI: 10.1520/D3588-98R17.2A more rigorous calculation of Z(T,P) at both base conditions and higherpressures can be made using the calculation procedures in “Compressibility andSuper Compressibility for Natural Gas and Other Hydrocarbon Gases,” AmericanGas Association
13、Transmission Measurement Committee Report 8, AGA Cat. No.XQ1285, 1985, AGA, 1515 Wilson Blvd., Arlington, VA 22209.3For 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 t
14、he standards Document Summary page onthe ASTM website.4The last approved version of this historical standard is referenced onwww.astm.org.5Available from Gas ProcessorsAssociation (GPA), 6526 E. 60th St., Tulsa, OK74145, http:/.6The sole source of supply of the program in either BASIC or FORTRANsuit
15、able for running on computers known to the committee at this time is the GasProcessorsAssociation. If you are aware of alternative suppliers, please provide thisinformation to ASTM International Headquarters. Your comments will receivecareful consideration at a meeting of the responsible technical c
16、ommittee1, whichyou may attend.7Available from Thermodynamics Research Center, The TexasA&M University,College Station, TX 77843-3111.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordan
17、ce with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.12.4 ANSI Standard:ANSI Z 132.1-1969
18、: Base Conditions of Pressure and Tem-perature for the Volumetric Measurement of NaturalGas8,93. Terminology3.1 Definitions:3.1.1 British thermal unitthe defined International TablesBritish thermal unit (Btu).3.1.1.1 DiscussionThe defining relationships are:1 Btulb1= 2.326 Jg1(exact)1 lb = 453.592 3
19、7 g (exact)By these relationships, 1 Btu = 1 055.055 852 62 J (exact). Formost purposes, the value (rounded) 1 Btu = 1055.056 J isadequate.3.1.2 compressibility factor (z)the ratio of the actualvolume of a given mass of gas at a specified temperature andpressure to its volume calculated from the ide
20、al gas law underthe same conditions.3.1.3 gross heating valuethe amount of energy transferredas heat from the complete, ideal combustion of the gas with air,at standard temperature, in which all the water formed by thereaction condenses to liquid. The values for the pure gasesappear in GPAStandard 2
21、145, which is revised annually. If thegross heating value has a volumetric rather than a mass ormolar basis, a base pressure must also be specified.3.1.4 net heating valuethe amount of energy transferred asheat from the total, ideal combustion of the gas at standardtemperature in which all the water
22、 formed by the reactionremains in the vapor state. Condensation of any “spectator”water does not contribute to the net heating value. If the netheating value has a volumetric rather than a mass or molarbasis, a base pressure must also be specified.3.1.5 relative densitythe ratio of the density of th
23、e gaseousfuel, under observed conditions of temperature and pressure, tothe density of dry air (of normal carbon dioxide content) at thesame temperature and pressure.3.1.6 standard cubic foot of gasthe amount of gas thatoccupies 1 ft3(0.028 m3) at a temperature of 60F (15.6C)under a given base press
24、ure and either saturated with watervapor (wet) or free of water vapor (dry) as specified (seeANSIZ 132.1). In this practice, calculations have been made at14.696 psia and 60F (15.6C), because the yearly update ofGPA 2145 by the Thermodynamics Research Center, on whichthese calculations are based, ar
25、e given for this base pressure.Conversions to other base conditions should be made at the endof the calculation to reduce roundoff errors.3.1.7 standard temperature (USA)60F (15.6C).3.2 Symbols:3.2.1 Nomenclature:3.2.1.1 Bsecond virial coefficient for gas mixture3.2.1.2 =ijsummation factor for calcu
26、lating real gascorrection (alternate method)3.2.1.3 (cor)corrected for water content3.2.1.4 (dry)value on water-free basis3.2.1.5 ddensity for gas relative to the density of air.3.2.1.6 didideal relative density or relative molar mass,that is, molar mass of gas relative to molar mass of air3.2.1.7 G
27、idmolar mass ratio3.2.1.8 Hmidgross heating value per unit mass3.2.1.9 Hvidgross heating value per unit volume3.2.1.10 Hnidgross heating value per unit mole3.2.1.11 hmidnet heating value per unit mass3.2.1.12 hvidnet heating value per unit volume3.2.1.13 hnidnet heating value per unit mole3.2.1.14 a
28、, b, cin Eq 1, integers required to balance theequation: C, carbon; H, hydrogen; S, sulfur; O, oxygen3.2.1.15 (id)ideal gas state3.2.1.16 (l)liquid phase3.2.1.17 Mmolar mass3.2.1.18 mmass flow rate3.2.1.19 nnumber of components3.2.1.20 Ppressure in absolute units (psia)3.2.1.21 Qidideal energy per u
29、nit time released as heatupon combustion3.2.1.22 Rgas constant, 10.7316 psia.ft3/(lb molR) in thispractice (based upon R = 8.314 48 J/(molK)3.2.1.23 (sat)denotes saturation value3.2.1.24 Tabsolute temperature, R = F + 459.67 or K =C + 273.153.2.1.25 (T, P)value dependent upon temperature andpressure
30、3.2.1.26 Vgas volumetric flow rate3.2.1.27 xmole fraction3.2.1.28 Zgas compressibility factor repeatability of prop-erty3.2.1.29 repeatability of property3.2.1.30 density in mass per unit volume3.2.1.31(j51nproperty summed for Components 1 throughn, where n represents the total number of components
31、in themixture3.2.2 Superscripts:3.2.2.1 idideal gas value3.2.2.2 lliquid3.2.2.3 value at saturation (vapor pressure)3.2.2.4 reproducibility3.2.3 Subscripts:3.2.3.1 avalue for air3.2.3.2 arelative number of atoms of carbon in Eq 13.2.3.3 brelative number of atoms of hydrogen in Eq 13.2.3.4 crelative
32、number of atoms of sulfur in Eq 13.2.3.5 jproperty for component j3.2.3.6 iinon-ideal gas property for component i3.2.3.7 ijnon-ideal gas property for mixture of i and j3.2.3.8 jjnon-ideal gas property for component j3.2.3.9 wvalue for water8Available from American National Standards Institute (ANSI
33、), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.9Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D03-1007.D3588 98 (2017)23.2.3.10 1property for Component 13.2.3.11 2property for Component 24. Summary of Pract
34、ice4.1 The ideal gas heating value and ideal gas relativedensity at base conditions (14.696 psia and 60F (5.6C) arecalculated from the molar composition and the respective idealgas values for the components; these values are then adjustedby means of a calculated compressibility factor.5. Significanc
35、e and Use5.1 The heating value is a measure of the suitability of apure gas or a gas mixture for use as a fuel; it indicates theamount of energy that can be obtained as heat by burning a unitof gas. For use as heating agents, the relative merits of gasesfrom different sources and having different co
36、mpositions canbe compared readily on the basis of their heating values.Therefore, the heating value is used as a parameter fordetermining the price of gas in custody transfer. It is also anessential factor in calculating the efficiencies of energy con-version devices such as gas-fired turbines. The
37、heating valuesof a gas depend not only upon the temperature and pressure,but also upon the degree of saturation with water vapor.However, some calorimetric methods for measuring heatingvalues are based upon the gas being saturated with water at thespecified conditions.5.2 The relative density (speci
38、fic gravity) of a gas quantifiesthe density of the gas as compared with that of air under thesame conditions.6. Methods of Analysis6.1 Determine the molar composition of the gas in accor-dance with anyASTM or GPAmethod that yields the completecomposition, exclusive of water, but including all other
39、com-ponents present in amounts of 0.1 % or more, in terms ofcomponents or groups of components listed in Table 1.At least98 % of the sample must be reported as individual components(that is, not more than a total of 2 % reported as groups ofcomponents such as butanes, pentanes, hexanes, butenes, and
40、so forth). Any group used must be one of those listed in Table1 for which average values appear. The following test methodsare applicable to this practice when appropriate for the sampleunder test: Test Methods D1717, D1945, D2163, and D2650.7. CalculationIdeal Gas Values; Ideal Heating Value7.1 An
41、ideal combustion reaction in general terms for fueland air in the ideal gas state is:CaHbScid!1a1b/41c!O2id! 5 aCO2id!1h/2!H2Oid or l!(1)1cSO2id!where id denotes the ideal gas state and l denotes liquidphase. The ideal net heating value results when all the waterremains in the ideal gas state. The i
42、deal gross heating valueresults when all the water formed by the reaction condenses toliquid. For water, the reduction from H2O(id)toH2O(l)isHwid Hwl, the ideal enthalpy of vaporization, which is somewhatlarger than the enthalpy of vaporization Hwy Hwl .7.1.1 Because the gross heating value results
43、from an idealcombustion reaction, ideal gas relationships apply. The idealgross heating value per unit mass for a mixture, Hmid, is:Hmid5(j51nxjMjHm,jid/(j51nxjMj(2)where: xjis the mole fraction of Component j, Mjis the molarmass of Component j from Table 1, and n is the total numberof components.7.
44、1.2 Hm,jidis the pure component, ideal gross heating valueper unit mass for Component j (at 60F (15.6C) in Table 1).Values of Hmidare independent of pressure, but they vary withtemperature.7.2 Ideal Gas Density7.2.1 The ideal gas density, id, is:id5 P/RT!(j51nxjMj5 MP/RT (3)where: M is the molar mas
45、s of the mixture,M 5(j51nxjMj(4)P is the base pressure in absolute units (psia), R is the gasconstant, 10.7316 psia.ft3/(lb molR) in this practice, basedupon R = 8.314 48 J/(molK), T is the base temperature inabsolute units (R = F + 459.67). Values of the ideal gasdensity at 60F (15.6C) and 14.696 p
46、sia are in GPA Standard2145.7.3 Ideal Relative Density:7.3.1 The ideal relative density didis:did5(j51nxjdj5(xjMj/Ma5 M/Ma(5)where: Mais the molar mass of air. The ideal relative densityis the molar mass ratio.7.4 Gross Heating Value per Unit Volume:7.4.1 Multiplication of the gross heating value pe
47、r unit massby the ideal gas density provides the gross heating value perunit volume, Hvid:Hvid5 idHmid5(j51nxjHv,jid(6)Hv,jidis the pure component gross heating value per unitvolume for Component j at specified temperature and pressure(60F (15.6C) and 14.696 psia in Table 1, ideal gas values).7.4.2
48、Conversion of values in Table 1 to different pressurebases results from multiplying by the pressure ratio:HvidP! 5 HvidP 5 14.696! 3P/14.696 (7)7.5 Real Gas ValuesCompressibility Factor:7.5.1 The compressibility factor is:ZT,P! 5 id/ 5 MP/RT!/ (8)where is the real gas density in mass per unit volume
49、. Atconditions near ambient, the truncated virial equation of statesatisfactorily represents the volumetric behavior of natural gas:D3588 98 (2017)3ZT,P! 5 11BP/RT (9)where B is the second virial coefficient for the gas mixture.The second virial coefficient for a mixture is:B 5 x12B111x22B2211xn2Bnn12x1x2B12112xn21xnBn2i,n(10)5(i51n(j51nxixjBijwhere Bjjis the second virial coefficient for Component j andBijis the second
