ASTM D2421-21e1

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
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Designation: D2421 − 21
Standard Practice for
Interconversion of Analysis of C and Lighter Hydrocarbons
to Gas-Volume, Liquid-Volume, or Mass Basis
This standard is issued under the fixed designation D2421; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
ε NOTE—Editorially corrected Table 2 in June 2021.
1. Scope* now part of NIST), except where otherwise noted. The values
for methane, ethylene, and acetylene are not those of pure
1.1 This practice describes the procedure for the intercon-
materials but are assumed to apply as a component of a liquid
version of the analysis of C and lighter hydrocarbon mixtures
mixture.
to gas-volume (mole), liquid-volume, or mass basis.
2.2 The conversion factors for 1 mL of ideal gas at 15.6 °C
1.2 The computation procedures described assume that
(60 °F) and 101.325 kPa (760 mm Hg) to millilitres of liquid at
gas-volume percentages have already been corrected for non-
15.6 °C (60 °F) have been calculated as follows: For 1 mL gas
idealityofthecomponentsasapartoftheanalyticalprocessby
which they have been obtained. These are numerically the at 15.6 °C (60 °F), 101.325 kPa (760 mm Hg),
same as mole percentages.
1.3 The procedure assumes the absence of nonadditivity L 5 ~273.15 K/288.71! 3 ~M/22414! (1)
corrections for mixtures of the pure liquid compounds. This is
3 1/ relative density 3 0.999016
@ @~ ! ~ !##
approximately true only for mixtures of hydrocarbons of the
same number of carbon atoms, and in the absence of diolefins
54.2252 310 3 M/relative density
~ !
and acetylenic compounds.
5millilitres liquid at 15.6 °C 60 °F
~ !
1.4 The values stated in SI units are to be regarded as
standard. The values given in parentheses after SI units are
where:
provided for information only and are not considered standard.
L = calculated liquid volume, mL,
1.5 This standard does not purport to address all of the
M = molecular weight, g-mol,
safety concerns, if any, associated with its use. It is the
22414 = calculated from V=nRT/P,
responsibility of the user of this standard to establish appro- n = 1 g-mol,
–1 –1
priate safety, health, and environmental practices and deter- R = 8314.472 mL kPa K g-mol ,
T = 273.15 K, and
mine the applicability of regulatory limitations prior to use.
P = 101.325 kPa.
1.6 This international standard was developed in accor-
dance with internationally recognized principles on standard-
2.3 Where ideal gas volumes have been measured at tem-
ization established in the Decision on Principles for the
peratures and pressures different from 15.6 °C (60 °F) at
Development of International Standards, Guides and Recom-
101.325 kPa (760 mm Hg), they shall be corrected to these
mendations issued by the World Trade Organization Technical
conditions.
Barriers to Trade (TBT) Committee.
3. Significance and Use
2. Source of Data
3.1 For custody transfer and other purposes, it is frequently
2.1 Thebasicvaluesfortherelativedensity15.6 °C⁄15.6 °C
necessary to convert a component analysis of light hydrocar-
(60 °F⁄60 °F) of the pure compounds have been obtained from
bon mixture from one basis (either gas volume, liquid volume,
TRC (formerly the Thermodynamics Research Center, and
or mass) to another.
3.2 The component distribution data of light hydrocarbon
This practice is under the jurisdiction of ASTM Committee D02 on Petroleum
Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcom-
mixtures can be used to calculate physical properties such as
mittee D02.H0 on Liquefied Petroleum Gas.
relative density, vapor-pressure, and calorific value. Consistent
Current edition approved April 1, 2021. Published May 2021. Originally
and accurate conversion data are extremely important when
approved in 1965. Last previous edition approved in 2019 as D2421 – 19. DOI:
10.1520/D2421-21E01. calculating vapor, liquid, or mass equivalence.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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D2421 − 21
4. Procedure 4.2 Add the products or quotients obtained in accordance
with 4.1.
4.1 To convert from the original to the desired basis,
multiplyordividethepercentofeachcompoundintheoriginal
4.3 Multiply the products or quotients obtained in accor-
basis according to the schedule shown in Table 1. Perform the
dance with 4.1 by 100 divided by the sum of the products or
calculation, using the corresponding factor indicated in Table
quotients. Round off the results so that the same number of
2. Carry at least one more significant figure in all of the
significant figures is obtained in the final answer as was used in
calculations than the number of significant figures in the
the original analysis.
original analysis.
4.1.1 The factors or percentages may be multiplied by any
constantnumberforconvenience(suchasmovingthedecimal)
without changing the end result.
TABLE 1 Conversion Factors Scheduled
Factor Column in
Original Basis Desired Basis Operation
Table 2
Gas volume mass multiply by 1
Gas volume liquid volume multiply by 2
Mass gas volume divide by 1
Mass liquid volume divide by 3
Liquid volume gas volume divide by 2
Liquid volume mass multiply by 3
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D2421 − 21
A
TABLE 2 Mass-Volume Data for Liquefied Petroleum Gases and Low Boiling Hydrocarbons
Column 1 Column 2 Column 3
Liquid Volume in mL of
Relative Density
Molecular Mass 1 mL of ideal gas at
Compound 15.6 °C ⁄15.6 °C
g/mol 15.6 °C (60 °F) and
(60 °F ⁄60 °F) (Vacuum)
101.325 kPa (760 mm Hg)
B
Methane 16.0425 0.0022594 0.3
C
Ethane 30.0690 0.0035659 0.35628
B
Ethyne (acetylene) 26.037 0.0025993 0.42323
B D
Ethylene 28.0532 0.0032 0.37
C
Propane 44.0956 0.0036734 0.50719
C
Propene (propylene) 42.0797 0.0034021 0.52260
C
Propadiene (allene) 40.065 0.0028438 0.59528
C
Propyne (meth
...