1、Designation: D3588 98 (Reapproved 2011)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.2. Referenced Docu
6、ments2.1 ASTM Standards:3D1717 Method of Test for Analysis of Commercial ButaneButiene Mixtures and Isolutylene by Gas Chromatogra-phy4D1945 Test Method for Analysis of Natural Gas by GasChromatographyD1946 Practice for Analysis of Reformed Gas by GasChromatographyD2163 Test Method for Analysis of L
7、iquefied Petroleum(LP) Gases and Propene Concentrates by Gas Chromatog-raphyD2650 Test Method for Chemical Composition of Gases byMass Spectrometry2.2 GPA Standards:GPA2145 Physical Constants for the Paraffin Hydrocarbonsand Other Components in Natural Gas5GPA Standard 2166 Methods of Obtaining Natu
8、ral 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 Natural Gas andSimilar Gaseous Mixtures by Gas Chromatography5GPA Te
9、chnical Publication TP-17 Table of Physical Prop-erties of Hydrocarbons for Extended Analysis of NaturalGases5GPSA Data Book, Fig. 23-2, Physical Constants52.3 TRC Document:TRC Thermodynamic TablesHydrocarbons72.4 ANSI Standard:ANSI Z 132.1-1969: Base Conditions of Pressure andTemperature for the Vo
10、lumetric Measurement of NaturalGas8,93. Terminology3.1 Definitions:1This practice is under 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 No
11、v. 1, 2011. Published May 2012. Originallyapproved in 1998. Last previous edition approved in 2003 as D3588 98(2003).DOI: 10.1520/D3588-98R11.2A more rigorous calculation of Z(T,P) at both base conditions and higherpressures can be made using the calculation procedures in “Compressibility andSuper C
12、ompressibility for Natural Gas and Other Hydrocarbon Gases,” AmericanGas Association 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 Servic
13、e at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.4Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.5Available from Gas Processors Association (GPA), 6526 E. 60th St.
14、, Tulsa, OK74145, http:/.6The sole source of supply of the program in either BASIC or FORTRANsuitable 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 Headquar
15、ters. Your comments will receivecareful consideration at a meeting of the responsible technical committee1, 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
16、 mmass flow rate3.2.1.19 nnumber of components3.2.1.20 Ppressure in absolute units (psia)3.2.1.21 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
17、.1.24 Tabsolute temperature, R = F + 459.67 or K =C + 273.153.2.1.25 (T, P)value dependent upon temperature 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 drepeatability of property3.2.1.30 rdensity in mass
18、per unit volume3.2.1.31(j51nproperty summed for Components 1through n, where n represents the total number of componentsin the mixture3.2.2 Superscripts:3.2.2.1 idideal gas value3.2.2.2 lliquid3.2.2.3 svalue at saturation (vapor pressure)3.2.2.4 8reproducibility3.2.3 Subscripts:3.2.3.1 avalue for ai
19、r3.2.3.2 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 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
20、jjnon-ideal gas property for component j3.2.3.9 wvalue for water3.2.3.10 1property for Component 13.2.3.11 2property for Component 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 composit
21、ion and the respective idealgas values for the components; these values are then adjustedby means of a calculated compressibility 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
22、 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 compositions canbe compared readily on the basis of their heating values.Therefore, the heating value is used as a parameter forD3588 98 (2011)2determi
23、ning 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 heating valuesof a gas depend not only upon the temperature and pressure,but also upon the degree of saturation with water vapor.Howe
24、ver, some calorimetric methods for measuring heatingvalues are based upon the gas being saturated with water at thespecified conditions.5.2 The relative density (specific gravity) of a gas quantifiesthe density of the gas as compared with that of air under thesame conditions.6. Methods of Analysis6.
25、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 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
26、 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, andso forth). Any group used must be one of those listed in Table1 for which average values appear. The following test methodsare appli
27、cable 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 ideal combustion reaction in general terms for fueland air in the ideal gas state is:CaHbScid! 1 a 1 b/4 1 c!O2id! 5 aCO2id! 1 h/2!H
28、2O id or l!1 cSO2id! (1)TABLE 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
29、ft3Hydrogen H22.0159 0.069 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
30、O231.9988 1.104 8 0 0 0 0 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 1010.0 802.7
31、1 21 511 909.4 0.0116Ethane 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.
32、3 2657.6 19 658 3010.8 0.0478i-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
33、20 839 5502.5 4501.9 19 315 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
34、.491 2 3517.27 20 958 3985 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-Dimethyl
35、butane C6H1486.177 2.975 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 . . .C
36、yclohexane C6H1284.161 2.905 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 192
37、6.1 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 (ave) C5H1272.150 2.491 2 3534 21 056 4003 3267 19 469 3702 0.062Hexanes (ave) C6H1486.177 2.975 5 4190 20 904 4747 3879 19 35
38、3 4395 0.080Butenes (ave) C4H856.108 1.937 2 2716 20 811 3077 2538 19 450 2876 0.046Pentenes (ave) C5H1070.134 2.421 5 3375 20 691 3824 3153 19 328 3572 0.060AThis table is consistent with GPA 2145-89, but it is necessary to use the values from the most recent edition of GPA 2145 for custody transfe
39、r calculations.B1984 Atomic Weights: C = 12.011, H = 1.00794, O = 15.9994, N = 14.0067, S = 32.06.CMolar mass ratio is the ratio of the molar mass of the gas to that of air.DBased upon ideal reaction; the entry for water represents the total enthalpy of vaporization.EComposition from: F. E. Jones, J
40、. Res. Nat. Bur. Stand., Vol. 83, 419, 1978.D3588 98 (2011)3where 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 ideal gross heating valueresults when all the water formed by the reaction condenses t
41、oliquid. 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 Hwl8 .7.1.1 Because the gross heating value results from an idealcombustion reaction, ideal gas relationships apply. The idealgross heat
42、ing 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.7.1.2 Hm,jidis the pure component, ideal gross heating valueper unit mass for Componen
43、t 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, rid, is:rid5 P/RT!(j51nxjMj5 MP/RT (3)where: M is the molar mass of the mixture,M 5(j51nxjMj(4)P is the base pressure in absolute units (psia), R
44、 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 psia are in GPA Standard2145.7.3 Ideal Relative Density:7.3.1 The ideal relative de
45、nsity 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 per unit massby the ideal gas density provides the gross heating value perunit vol
46、ume, Hvid:Hvid5ridHmid5(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 Conversion of values in Table 1 to different pressurebases results from multiply
47、ing by the pressure ratio:HvidP! 5 HvidP 5 14.696! 3 P/14.696 (7)7.5 Real Gas ValuesCompressibility Factor:7.5.1 The compressibility factor is:Z T,P! 5rid/r5MP/RT!/r (8)where r is the real gas density in mass per unit volume. Atconditions near ambient, the truncated virial equation of statesatisfact
48、orily represents the volumetric behavior of natural gas:Z T,P!51 1 BP/RT (9)where B is the second virial coefficient for the gas mixture.The second virial coefficient for a mixture is:B 5 x12B111 x22B221 1 xn2Bnn1 2x1x2B121 1 2xn1xnBni,n5(i51n(j51nxixjBij(10)where Bjjis the second virial coefficient
49、 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 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
