ASTM D3588-98(2011)
(Practice)Standard Practice for Calculating Heat Value, Compressibility Factor, and Relative Density of Gaseous Fuels
Standard Practice for Calculating Heat Value, Compressibility Factor, and Relative Density of Gaseous Fuels
SIGNIFICANCE AND USE
The heating value is a measure of the suitability of a pure gas or a gas mixture for use as a fuel; it indicates the amount of energy that can be obtained as heat by burning a unit of gas. For use as heating agents, the relative merits of gases from different sources and having different compositions can be compared readily on the basis of their heating values. Therefore, the heating value is used as a parameter for determining the price of gas in custody transfer. It is also an essential factor in calculating the efficiencies of energy conversion devices such as gas-fired turbines. The heating values of 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 heating values are based upon the gas being saturated with water at the specified conditions.
The relative density (specific gravity) of a gas quantifies the density of the gas as compared with that of air under the same conditions.
SCOPE
1.1 This practice covers procedures for calculating heating value, relative density, and compressibility factor at base conditions (14.696 psia and 60°F (15.6°C)) for natural gas mixtures from compositional analysis. It applies to all common 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 gas, and retort coal gas, for which suitable methods of analysis as described in Section 6 are available. Calculation procedures for other base conditions are given.
1.2 The values stated in inch-pound units are to be regarded as the standard. The SI units given in parentheses are for information only.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D3588 − 98 (Reapproved 2011)
Standard Practice for
Calculating Heat Value, Compressibility Factor, and Relative
Density of Gaseous Fuels
This standard is issued under the fixed designation D3588; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope D1946Practice for Analysis of Reformed Gas by Gas
Chromatography
1.1 This practice covers procedures for calculating heating
D2163Test Method for Determination of Hydrocarbons in
value, relative density, and compressibility factor at base
Liquefied Petroleum (LP) Gases and Propane/Propene
conditions (14.696 psia and 60°F (15.6°C)) for natural gas
2 Mixtures by Gas Chromatography
mixtures from compositional analysis. It applies to all com-
D2650Test Method for Chemical Composition of Gases by
montypesofutilitygaseousfuels,forexample,drynaturalgas,
Mass Spectrometry
reformed gas, oil gas (both high and low Btu), propane-air,
2.2 GPA Standards:
carbureted water gas, coke oven gas, and retort coal gas, for
GPA2145Physical Constants for the Paraffin Hydrocarbons
which suitable methods of analysis as described in Section 6
and Other Components in Natural Gas
are available. Calculation procedures for other base conditions
GPA Standard 2166Methods of Obtaining Natural Gas
are given.
Samples for Analysis by Gas Chromatography
1.2 The values stated in inch-pound units are to be regarded
GPA 2172Calculation of Gross Heating Value, Relative
as the standard. The SI units given in parentheses are for
Density, and Compressibility Factor for Natural Gas
information only. 5,6
Mixtures from Compositional Analysis
1.3 This standard does not purport to address all of the
GPAStandard2261MethodofAnalysisforNaturalGasand
safety concerns, if any, associated with its use. It is the
Similar Gaseous Mixtures by Gas Chromatography
responsibility of the user of this standard to establish appro-
GPATechnical Publication TP-17Table of Physical Proper-
priate safety and health practices and determine the applica-
ties of Hydrocarbons for Extended Analysis of Natural
bility of regulatory limitations prior to use.
Gases
GPSA Data Book,Fig. 23-2, Physical Constants
2. Referenced Documents
2.3 TRC Document:
2.1 ASTM Standards:
TRC Thermodynamic Tables—Hydrocarbons
D1717Test Method for Test for Analysis of Commerical
2.4 ANSI Standard:
Butane-Butene Mixtures and Isolutylene by Gas Chroma-
ANSI Z 132.1-1969:Base Conditions of Pressure and Tem-
tography (Withdrawn 1984)
perature for the Volumetric Measurement of Natural
8,9
D1945Test Method for Analysis of Natural Gas by Gas
Gas
Chromatography
3. Terminology
3.1 Definitions:
This practice is under the jurisdiction of ASTM Committee D03 on Gaseous
Fuels and is the direct responsibility of Subcommittee D03.03 on Determination of
Heating Value and Relative Density of Gaseous Fuels.
Current edition approved Nov. 1, 2011. Published May 2012. Originally AvailablefromGasProcessorsAssociation(GPA),6526E.60thSt.,Tulsa,OK
approved in 1998. Last previous edition approved in 2003 as D3588–98(2003). 74145, http://www.gasprocessors.com.
DOI: 10.1520/D3588-98R11. The sole source of supply of the program in either BASIC or FORTRAN
A more rigorous calculation of Z(T,P) at both base conditions and higher suitable for running on computers known to the committee at this time is the Gas
pressures can be made using the calculation procedures in “Compressibility and ProcessorsAssociation.Ifyouareawareofalternativesuppliers,pleaseprovidethis
Super Compressibility for Natural Gas and Other Hydrocarbon Gases,” American information to ASTM International Headquarters. Your comments will receive
Gas Association Transmission Measurement Committee Report 8, AGA Cat. No. careful consideration at a meeting of the responsible technical committee , which
XQ1285, 1985, AGA, 1515 Wilson Blvd., Arlington, VA 22209. you may attend.
3 7
For referenced ASTM standards, visit the ASTM website, www.astm.org, or AvailablefromThermodynamicsResearchCenter,TheTexasA&MUniversity,
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM College Station, TX 77843-3111.
Standards volume information, refer to the standard’s Document Summary page on Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
the ASTM website. 4th Floor, New York, NY 10036, http://www.ansi.org.
4 9
The last approved version of this historical standard is referenced on Supporting data have been filed atASTM International Headquarters and may
www.astm.org. be obtained by requesting Research Report RR:D03-1007.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3588 − 98 (2011)
id
3.1.1 British thermal unit—the defined International Tables 3.2.1.11 h —net heating value per unit mass
m
British thermal unit (Btu).
id
3.2.1.12 h —net heating value per unit volume
v
3.1.1.1 Discussion—The defining relationships are:
id
–1 –1 3.2.1.13 h —net heating value per unit mole
n
1 Btu•lb = 2.326 J•g (exact)
1 lb = 453.592 37 g (exact) 3.2.1.14 a, b, c—in Eq 1, integers required to balance the
Bytheserelationships,1Btu=1055.05585262J(exact).For equation: C, carbon; H, hydrogen; S, sulfur; O, oxygen
most purposes, the value (rounded) 1 Btu = 1055.056 J is 3.2.1.15 (id)—ideal gas state
adequate. 3.2.1.16 (l)—liquid phase
3.2.1.17 M—molar mass
3.1.2 compressibility factor (z)—the ratio of the actual
3.2.1.18 m—mass flow rate
volume of a given mass of gas at a specified temperature and
3.2.1.19 n—number of components
pressure to its volume calculated from the ideal gas law under
3.2.1.20 P—pressure in absolute units (psia)
the same conditions.
id
3.2.1.21 Q —ideal energy per unit time released as heat
3.1.3 gross heating value—theamountofenergytransferred
upon combustion
asheatfromthecomplete,idealcombustionofthegaswithair, 3
3.2.1.22 R—gasconstant,10.7316psia.ft /(lbmol•R)inthis
at standard temperature, in which all the water formed by the
practice (based upon R = 8.31448 J/(mol•K))
reaction condenses to liquid. The values for the pure gases
3.2.1.23 (sat)—denotes saturation value
appear in GPAStandard 2145, which is revised annually. If the
3.2.1.24 T—absolute temperature, °R = °F + 459.67 or K =
gross heating value has a volumetric rather than a mass or
°C + 273.15
molar basis, a base pressure must also be specified.
3.2.1.25 (T, P)—value dependent upon temperature and
3.1.4 netheatingvalue—theamountofenergytransferredas pressure
heat from the total, ideal combustion of the gas at standard
3.2.1.26 V—gas volumetric flow rate
temperature in which all the water formed by the reaction
3.2.1.27 x—mole fraction
remains in the vapor state. Condensation of any “spectator”
3.2.1.28 Z—gascompressibilityfactorrepeatabilityofprop-
water does not contribute to the net heating value. If the net
erty
heating value has a volumetric rather than a mass or molar
3.2.1.29 δ—repeatability of property
basis, a base pressure must also be specified.
3.2.1.30 ρ—density in mass per unit volume
n
3.1.5 relativedensity—theratioofthedensityofthegaseous
3.2.1.31 —property summed for Components 1 through
(
j51
fuel,underobservedconditionsoftemperatureandpressure,to
n, where n represents the total number of components in the
the density of dry air (of normal carbon dioxide content) at the
mixture
same temperature and pressure.
3.2.2 Superscripts:
3.1.6 standard cubic foot of gas—the amount of gas that
3.2.2.1 id—ideal gas value
3 3
occupies 1 ft (0.028 m ) at a temperature of 60°F (15.6°C)
3.2.2.2 l—liquid
under a given base pressure and either saturated with water
3.2.2.3 σ—value at saturation (vapor pressure)
vapor(wet)orfreeofwatervapor(dry)asspecified(seeANSI
3.2.2.4 '—reproducibility
Z 132.1). In this practice, calculations have been made at
3.2.3 Subscripts:
14.696 psia and 60°F (15.6°C), because the yearly update of
3.2.3.1 a—value for air
GPA2145 by theThermodynamics Research Center, on which
3.2.3.2 a—relative number of atoms of carbon in Eq 1
these calculations are based, are given for this base pressure.
3.2.3.3 b—relative number of atoms of hydrogen in Eq 1
Conversionstootherbaseconditionsshouldbemadeattheend
3.2.3.4 c—relative number of atoms of sulfur in Eq 1
of the calculation to reduce roundoff errors.
3.2.3.5 j—property for component j
3.1.7 standard temperature (USA)—60°F (15.6°C).
3.2.3.6 ii—non-ideal gas property for component i
3.2.3.7 ij—non-ideal gas property for mixture of i and j
3.2 Symbols:
3.2.3.8 jj—non-ideal gas property for component j
3.2.1 Nomenclature:
3.2.3.9 w—value for water
3.2.1.1 B—second virial coefficient for gas mixture
3.2.3.10 1—property for Component 1
3.2.1.2 =β —summation factor for calculating real gas
ij
3.2.3.11 2—property for Component 2
correction (alternate method)
4. Summary of Practice
3.2.1.3 (cor)—corrected for water content
4.1 The ideal gas heating value and ideal gas relative
3.2.1.4 (dry)—value on water-free basis
density at base conditions (14.696 psia and 60°F (5.6°C)) are
3.2.1.5 d—density for gas relative to the density of air.
id
calculatedfromthemolarcompositionandtherespectiveideal
3.2.1.6 d —ideal relative density or relative molar mass,
gas values for the components; these values are then adjusted
that is, molar mass of gas relative to molar mass of air
id
by means of a calculated compressibility factor.
3.2.1.7 G —molar mass ratio
id
3.2.1.8 H —gross heating value per unit mass
m
5. Significance and Use
id
3.2.1.9 H —gross heating value per unit volume
v
5.1 The heating value is a measure of the suitability of a
id
3.2.1.10 H —gross heating value per unit mole pure gas or a gas mixture for use as a fuel; it indicates the
n
D3588 − 98 (2011)
amountofenergythatcanbeobtainedasheatbyburningaunit 5.2 Therelativedensity(specificgravity)ofagasquantifies
of gas. For use as heating agents, the relative merits of gases the density of the gas as compared with that of air under the
from different sources and having different compositions can same conditions.
be compared readily on the basis of their heating values.
6. Methods of Analysis
Therefore, the heating value is used as a parameter for
determining the price of gas in custody transfer. It is also an 6.1 Determine the molar composition of the gas in accor-
essential factor in calculating the efficiencies of energy con- dancewithanyASTMorGPAmethodthatyieldsthecomplete
version devices such as gas-fired turbines. The heating values composition, exclusive of water, but including all other com-
of a gas depend not only upon the temperature and pressure, ponents present in amounts of 0.1% or more, in terms of
but also upon the degree of saturation with water vapor. componentsorgroupsofcomponentslistedinTable1.Atleast
However, some calorimetric methods for measuring heating 98%ofthesamplemustbereportedasindividualcomponents
valuesarebaseduponthegasbeingsaturatedwithwateratthe (that is, not more than a total of 2% reported as groups of
specified conditions. components such as butanes, pentanes, hexanes, butenes, and
A
TABLE 1 Properties of Natural Gas Components at 60°F and 14.696 psia
D
Ideal Gross Heating Value Ideal Net Heating Value
Summation
Molar Mass, Molar Mass,
id id id id id id
Compound Formula Factor, b ,
–1B idC i
H , H , H , h , h , h ,
n m v n m v
lb·lbmol Ratio, G
−1
–1 –1 –3 –1 –1 –3
psia
kJ · mol Btu · lbm Btu · ft kJ · mol Btu · lbm Btu · ft
Hydrogen H 2.0159 0.069 60 286.20 6 1022 324.2 241.79 51 566 273.93 0
Helium He 4.0026 0.138 20 0 0 0 0 0 0 0
Water H O 18.0153 0.622 02 44.409 1059.8 50.312 0 0 0 0.0623
Carbon monoxide CO 28.010 0.967 11 282.9 4342 320.5 282.9 4 342 320.5 0.0053
Nitrogen N 28.0134 0.967 23 0 0 0 0 0 0 0.0044
Oxygen O 31.9988 1.104 8 0 0 0 0 0 0 0.0073
Hydrogen sulfide H S 34.08 1.176 7 562.4 7 094.2 637.1 517.99 6 534 586.8 0.0253
Argon Ar 39.948 1.379 3 0 0 0 0 0 0 0.0071
Carbon dioxide CO 44.010 1.519 6 0 0 0 0 0 0 0.0197
E
Air 28.9625 1.000 0 0 0 0 0 0 0 0.0050
Methane CH 16.043 0.553 92 891.63 23 891 1010.0 802.71 21 511 909.4 0.0116
Ethane C H 30.070 1.038 2 1562.06 22 333 1769.7 1428.83 20 429 1618.7 0.0239
2 6
Propane C H 44.097 1.522 6 2220.99 21 653 2516.1 2043.3 19 922 2314.9 0.0344
3 8
i-Butane C H 58.123 2.006 8 2870.45 21 232 3251.9 2648.4 19 590 3000.4 0.0458
4 10
n-Butane C H 58.123 2.006 8 2879.63 21 300 3262.3 2657.6 19 658 3010.8 0.0478
4 10
i-Pentane C H 72.150 2.491 2 3531.5 21 043 4000.9 3265.0 19 456 3699.0 0.0581
5 12
n-Pentane C H 72.150 2.491 2 3535.8 21 085 4008.9 3269.3 19 481 3703.9 0.0631
5 12
n-Hexane C H 86.177 2.975 5 4198.1 20 943 4755.9 3887.2 19 393 4403.9 0.0802
6 14
n-Heptane C H 100.204 3.459 8 4857.2 20 839 5502.5 4501.9 19 315 5100.3 0.0944
7 16
n-Octane C H 114.231 3.944 1 5515.9 20 759 6248.9 5116.2 19 256 5796.2 0.1137
8 18
n-Nonane C H 128.258 4.428 4 6175.9 20 701 6996.5 5731.8 19 213 6493.6 0.1331
9 20
n-Decane C H 142.285 4.912 7 6834.9 20 651 7742.9 6346.4 19 176 7189.9 0.1538
10 22
Neopentane C H 72.015 2.491 2 3517.27 20 958 3985 3250.8 19 371 3683
5 12
2-Methylpentane C H 86.177 2.975 5 4190.43 20 905 4747 3879.6 19 355 4395 0.080
6 14
3-Methylpentane C H 86.177 2.975 5 4193.03 20 918 4750 3882.2 19 367 4398 0.080
6 14
2,2-Dimethylbutane C H 86.177 2.975 5 4180.63 20 856 4736 3869.8 19 306 4384 0.080
6 14
2,3-Dimethylbutane C H 86.177 2.975 5 4188.41 20 895 4745 3877.5 19 344 4393 0.080
6 14
Cyclopropane C H 42.081 1.452 9 2092.78 21 381 2371 1959.6 20 020 2220 . . .
3 6
Cyclobutane C H 56.108 1.937 3 2747.08 21 049 2747 2569.4 19 688 2911 . . .
4 8
Cyclopentane C H 70.134 2.421 5 3322.04 20 364 3764 3100.0 19 003 3512 . . .
5 10
Cyclohexane C H 84.161 2.905 9 3955.84 20 208 4482 3689.4 18 847 4180 . . .
6 12
Ethyne (acetylene) C H 26.038 0.899 0 1301.32 21 487 1474 1256.9 20 753 1424 0.021
2 2
Ethene (ethylene) C H 28.054 0.968 6 1412.06 21 640 1600 1323.2 20 278 1499 0.020
2 4
Propene (propylene) C H 42.081 1.452 9 2059.35 21 039 2333 1926.1 19 678 2182 0.033
3 6
Benzene C H 78.114 2.697 1 3202.74 18 177 3742 3169.5 17 444 3591 0.069
6 6
Butanes (ave) C H 58.123 2.006 8 2875 21 266 3257 2653 19 623 3006 0.046
4 10
Pentanes (ave) C H 72.150 2.491 2 3534 21 056 4003 3267 19 469 3702 0.062
5 12
Hexanes (ave) C H 86.177 2.975 5 4190 20 904 4747 3879 19 353 4395 0.080
6 14
Butenes (ave) C H 56.108 1.937 2 2716 20 811 3077 2538 19 450 2876 0.046
4 8
Pentenes (ave) C H 70.134 2.421 5 3375 20 691 3824 3153 19 328 3572 0.060
5 10
A
This table is consistent with GPA 2145-89, but it is necessary to use the values from the
...
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