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Test Method for Test for Analysis of CommericalButane-Butene Mixtures and Isolutylene by Gas Chroma-tography (Withdrawn 1984)4D1945 Test Method for Analysis of Natural Gas by GasChromatographyD1946 Practice for Analysis of Reformed Gas by GasChro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 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
17、 Qidideal energy per unit 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 t
18、emperature andpressure3.2.1.26 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
19、 number of components 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
20、Eq 13.2.3.4 crelative 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 Sta
21、ndards Institute (ANSI), 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 Componen
22、t 24. Summary of Practice4.1 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
23、 factor.5. Significance 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 a
24、nd having different compositions 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 ga
25、s-fired turbines. The 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 r
26、elative density (specific 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, bu
27、t including all other 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,
28、 hexanes, butenes, andso 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; Idea
29、l Heating Value7.1 An 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
30、ideal gas state. The ideal 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
31、heating value results 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
32、numberof components.7.1.2 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)whe
33、re: M is the molar mass 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 60
34、F (15.6C) and 14.696 psia 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
35、gross heating value per 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, id
36、eal gas values).7.4.2 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 i
37、n mass per unit volume. 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
38、 x12B111x22B2211xn2Bnn12x1x2B12112xn21xnBn2i,n(10)5(i51n(j51nxixjBijwhere Bjjis the second virial coefficient for Component j andBijis the second cross virial coefficient for Components i and j.The second virial coefficients are functions of temperature. Eq9 can be used with Eq 10 for calculation of
39、 the compressibilityfactor for the various pressure bases, but it is not accurate atpressures greater than two atmospheres. Special treatment isnot required for H2and He at mole fractions up to 0.01.Calculations can be made with Bjj= 0 for hydrogen and helium.7.5.2 Eq 9 and Eq 10 for calculation of
40、Z(T,P) for a gasmixture are rigorous but require considerable calculations andinformation that is not always available. An alternative, ap-proximate expression for Z(T,P) that is more convenient forhand calculations is:ZT,P! 5 1 2 PF(j51nxj=jjG2(11)where jj=Bjj/RT and =jjis the summation factor forT
41、ABLE 1 Properties of Natural Gas Components at 60F and 14.696 psiaACompound FormulaMolar Mass,lblbmol1BMolar Mass,Ratio, GidCIdeal Gross Heating ValueDIdeal Net Heating ValueSummationFactor, bi,psia1Hnid, Hmid, Hvid, hnid, hmid, hvid,kJ mol1Btu lbm1Btu ft3kJ mol1Btu lbm1Btu ft3Hydrogen H22.0159 0.06
42、9 60 286.20 6 1022 324.2 241.79 51 566 273.93 0Helium He 4.0026 0.138 20 0 0 0 0 0 0 0Water H2O 18.0153 0.622 02 44.409 1059.8 50.312 0 0 0 0.0623Carbon monoxide CO 28.010 0.967 11 282.9 4342 320.5 282.9 4 342 320.5 0.0053Nitrogen N228.0134 0.967 23 0 0 0 0 0 0 0.0044Oxygen O231.9988 1.104 8 0 0 0 0
43、 0 0 0.0073Hydrogen sulfide H2S 34.08 1.176 7 562.4 7 094.2 637.1 517.99 6 534 586.8 0.0253Argon Ar 39.948 1.379 3 0 0 0 0 0 0 0.0071Carbon dioxide CO244.010 1.519 6 0 0 0 0 0 0 0.0197AirE28.9625 1.000 0 0 0 0 0 0 0 0.0050Methane CH416.043 0.553 92 891.63 23 891 1010.0 802.71 21 511 909.4 0.0116Etha
44、ne C2H630.070 1.038 2 1562.06 22 333 1769.7 1428.83 20 429 1618.7 0.0239Propane C3H844.097 1.522 6 2220.99 21 653 2516.1 2043.3 19 922 2314.9 0.0344i-Butane C4H1058.123 2.006 8 2870.45 21 232 3251.9 2648.4 19 590 3000.4 0.0458n-Butane C4H1058.123 2.006 8 2879.63 21 300 3262.3 2657.6 19 658 3010.8 0.
45、0478i-Pentane C5H1272.150 2.491 2 3531.5 21 043 4000.9 3265.0 19 456 3699.0 0.0581n-Pentane C5H1272.150 2.491 2 3535.8 21 085 4008.9 3269.3 19 481 3703.9 0.0631n-Hexane C6H1486.177 2.975 5 4198.1 20 943 4755.9 3887.2 19 393 4403.9 0.0802n-Heptane C7H16100.204 3.459 8 4857.2 20 839 5502.5 4501.9 19 3
46、15 5100.3 0.0944n-Octane C8H18114.231 3.944 1 5515.9 20 759 6248.9 5116.2 19 256 5796.2 0.1137n-Nonane C9H20128.258 4.428 4 6175.9 20 701 6996.5 5731.8 19 213 6493.6 0.1331n-Decane C10H22142.285 4.912 7 6834.9 20 651 7742.9 6346.4 19 176 7189.9 0.1538Neopentane C5H1272.015 2.491 2 3517.27 20 958 398
47、5 3250.8 19 371 36832-Methylpentane C6H1486.177 2.975 5 4190.43 20 905 4747 3879.6 19 355 4395 0.0803-Methylpentane C6H1486.177 2.975 5 4193.03 20 918 4750 3882.2 19 367 4398 0.0802,2-Dimethylbutane C6H1486.177 2.975 5 4180.63 20 856 4736 3869.8 19 306 4384 0.0802,3-Dimethylbutane C6H1486.177 2.975
48、5 4188.41 20 895 4745 3877.5 19 344 4393 0.080Cyclopropane C3H642.081 1.452 9 2092.78 21 381 2371 1959.6 20 020 2220 . . .Cyclobutane C4H856.108 1.937 3 2747.08 21 049 2747 2569.4 19 688 2911 . . .Cyclopentane C5H1070.134 2.421 5 3322.04 20 364 3764 3100.0 19 003 3512 . . .Cyclohexane C6H1284.161 2.
49、905 9 3955.84 20 208 4482 3689.4 18 847 4180 . . .Ethyne (acetylene) C2H226.038 0.899 0 1301.32 21 487 1474 1256.9 20 753 1424 0.021Ethene (ethylene) C2H428.054 0.968 6 1412.06 21 640 1600 1323.2 20 278 1499 0.020Propene (propylene) C3H642.081 1.452 9 2059.35 21 039 2333 1926.1 19 678 2182 0.033Benzene C6H678.114 2.697 1 3202.74 18 177 3742 3169.5 17 444 3591 0.069Butanes (ave) C4H1058.123 2.006 8 2875 21 266 3257 2653 19 623 3006 0.046Pentanes
