1、Designation: D 3588 98 (Reapproved 2003)Standard Practice forCalculating Heat Value, Compressibility Factor, and RelativeDensity of Gaseous Fuels1This standard is issued under the fixed designation D 3588; the number immediately following the designation indicates the year oforiginal adoption or, in
2、 the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers procedures for calculating heatingvalue, relative density, an
3、d compressibility 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 ov
4、en 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.
5、1.3 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 D
6、ocuments2.1 ASTM Standards:D 1717 Method for Analysis of Commercial Butane-ButeneMixtures and Isobutylene by Gas Chromatography3D 1945 Test Method for Analysis of Natural Gas by GasChromatography4D 1946 Practice for Analysis of Reformed Gas by GasChromatography4D 2163 Test Method for Analysis of Liq
7、uefied Petroleum(LP) Gases and Propane Concentrates by Gas Chromatog-raphy5D 2650 Test Method for Chemical Composition of Gases byMass Spectrometry52.2 GPA Standards:GPA 2145 Physical Constants for the Paraffin Hydrocarbonsand Other Components in Natural Gas6GPA Standard 2166 Methods of Obtaining Na
8、tural GasSamples for Analysis by Gas Chromatography6GPA 2172 Calculation of Gross Heating Value, RelativeDensity, and Compressibility Factor for Natural GasMixtures from Compositional Analysis6,7GPA Standard 2261 Method of Analysis for Natural Gas andSimilar Gaseous Mixtures by Gas Chromatography6GP
9、A Technical Publication TP-17 Table of Physical Prop-erties of Hydrocarbons for Extended Analysis of NaturalGases6GPSA Data Book, Fig. 23-2, Physical Constants62.3 TRC Document:TRC Thermodynamic TablesHydrocarbons82.4 ANSI Standard:ANSI Z 132.1-1969: Base Conditions of Pressure andTemperature for th
10、e Volumetric Measurement of NaturalGas9,103. 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 37 g (exact)1This practice is under the jurisdiction
11、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 May 10, 2003. Published May 2003. Originallyapproved in 1998. Last previous edition approved in 1998 as D 3588
12、 98.2A 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 Transmission Measurement Committee Report 8, AGA Cat.
13、 No.XQ1285, 1985, AGA, 1515 Wilson Blvd., Arlington, VA 22209.3Discontinued. See 1981 Annual Book of ASTM Standards, Vol 05.01.4Annual Book of ASTM Standards, Vol 05.06.5Annual Book of ASTM Standards, Vol 05.01.6Available from Gas Processors Association, 6526 E. 60th, Tulsa, OK 74145.7The sole sourc
14、e of supply of the program in either BASIC or FORTRANsuitable for running on computers known to the committee at this time is the GasProcessors Association. If you are aware of alternative suppliers, please provide thisinformation to ASTM International Headquarters. Your comments will receivecareful
15、 consideration at a meeting of the responsible technical committee1, whichyou may attend.8Available from Thermodynamics Research Center, The Texas A 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 co
16、mponents3.2.1.20 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 value3.2.1.24 Tabsolute temperature, R = F + 4
17、59.67 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 per unit volume3.2.1.31(j51nproperty s
18、ummed 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 air3.2.3.2 arelative number of atoms of
19、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 jjnon-ideal gas property for component
20、 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 composition and the respective idealgas values
21、 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 can be obtained as heat by burning a
22、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 fordetermining the price of gas in custody transfer. It is also
23、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.D 3588 98 (2003)2However, some calorimetric methods for me
24、asuring 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 Analysis6.1 Determine the molar composition of
25、the gas in accor-dance with any ASTM or GPA method 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 sample must be reported as individ
26、ual 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 applicable to this practice when appropr
27、iate for the sampleunder test: Test Methods D 1717, D 1945, D 2163, and D 2650.7. 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!H2O id or l!1 cSO2id! (1)where i
28、d 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 toliquid.TABLE 1 Properties of Natural Gas Components at 60F and 14.
29、696 psiaACompound FormulaMolar Mass,lblbmol1BMolar Mass,Ratio, GidCIdeal Gross Heating ValueDIdeal Net Heating ValueSummationFactor, bi,psia1Hnid, Hmid, Hvid, hnid, hmid, hvid,kJ mol1Btu lbm1Btuft3kJ mol1Btu lbm1Btuft3Hydrogen H22.0159 0.069 60 286.20 6 1022 324.2 241.79 51 566 273.93 0Helium He 4.0
30、026 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 0 0 0.0073Hydrogen sulfide H2S 34.08 1.176 7 562.4 7 094.2
31、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 0.0116Ethane C2H630.070 1.038 2 1562.06 22 333 1769.7 1428.83 20 429 1
32、618.7 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 0.0478i-Pentane C5H1272.150 2.491 2 3531.5 21 043 4000.9 3265.
33、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 19 315 5100.3 0.0944n-Octane C8H18114.231 3.944 1 5515.9 20 759
34、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 3985 3250.8 19 371 36832-Methylpentane C6H1486.177 2.975 5 4190
35、.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 5 4188.41 20 895 4745 3877.5 19 344 4393 0.080Cyclopropane C
36、3H642.081 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 2.905 9 3955.84 20 208 4482 3689.4 18 847 4180 . . .Ethyne (ac
37、etylene) 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 17 444 359
38、1 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 19 353 4395 0.080Butenes (ave) C4H856.108 1.937 2 2716 20 811 3077 2538 19 450 2876 0.046P
39、entenes (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 transfer calculations.B1984 Atomic Weights: C = 12.011, H = 1.00794, O = 15.9994, N = 14.006
40、7, 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. Res. Nat. Bur. Stand., Vol. 83, 419, 1978.D 3588 98 (2003)3For water, the reduction
41、 from H2O(id)toH2O(l)isHwid Hwl,the ideal enthalpy of vaporization, which is somewhat largerthan 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 heating value per unit mass for a mixt
42、ure, 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 Component j (at 60F (15.6C) in Table 1).Va
43、lues 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 is the gasconstant, 10.7316 psia.
44、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 density didis:did5(j51nxjdj5 ( xjMj/
45、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 volume, Hvid:Hvid5ridHmid5(j51nxjHv,j
46、id(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 multiplying by the pressure ratio:HvidP! 5
47、 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 statesatisfactorily represents the volumetric be
48、havior 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 for Component j andBijis the seco
49、nd 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 and Eq 10 for calculation of Z(T,P) for a gasmixture ar
