ASTM D2421-21e1

Standard Practice for Interconversion of Analysis of C<emph type="ital"><inf>5</inf ></emph> and Lighter Hydrocarbons to Gas-Volume, Liquid-Volume, or Mass Basis

SIGNIFICANCE AND USE
3.1 For custody transfer and other purposes, it is frequently necessary to convert a component analysis of light hydrocarbon mixture from one basis (either gas volume, liquid volume, or mass) to another.  
3.2 The component distribution data of light hydrocarbon mixtures can be used to calculate physical properties such as relative density, vapor-pressure, and calorific value. Consistent and accurate conversion data are extremely important when calculating vapor, liquid, or mass equivalence.
SCOPE
1.1 This practice describes the procedure for the interconversion of the analysis of C5 and lighter hydrocarbon mixtures to gas-volume (mole), liquid-volume, or mass basis.  
1.2 The computation procedures described assume that gas-volume percentages have already been corrected for nonideality of the components as a part of the analytical process by which they have been obtained. These are numerically the same as mole percentages.  
1.3 The procedure assumes the absence of nonadditivity corrections for mixtures of the pure liquid compounds. This is approximately true only for mixtures of hydrocarbons of the same number of carbon atoms, and in the absence of diolefins and acetylenic compounds.  
1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.  
1.5 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.6 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.

General Information

• Status: Published
• Publication Date: 31-Mar-2021
• ICS: 75.080 - Petroleum products in general
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.H0 - Liquefied Petroleum Gas

Standards Content (Sample)

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
5
1
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.
1
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
5
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
25
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.
1
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 th
...