ASTM D2421-95

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Designation: D 2421 – 95 An American National Standard
Standard Practice for
Interconversion of Analysis of C and Lighter Hydrocarbons
to Gas-Volume, Liquid-Volume, or Weight Basis
This standard is issued under the fixed designation D 2421; 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 (e) indicates an editorial change since the last revision or reapproval.
5 millilitres liquid at 15.6°C 60°F
1. Scope ~ !
1.1 This practice describes the procedure for the intercon-
where:
version of the analysis of C and lighter hydrocarbon mixtures
M 5 molecular weight of the pure compound,
to gas-volume (mole), liquid-volume, or weight in vacuum
and
basis.
Relative density 5 relative density, 15.6/15.6°C (60/60°F)
1.2 The computation procedures described assume that
(vacuum), of the pure compound.
gas-volume percentages have already been corrected for non-
2.3 Where ideal gas volumes have been measured at tem-
ideality of the components as a part of the analytical process by
peratures and pressures different from 15.6°C (60°F) at 760
which they have been obtained. These are numerically the
mm Hg, they must be corrected to these conditions.
same as mole percentages.
3. Significance and Use
1.3 The procedure assumes the absence of nonadditivity
corrections for mixtures of the pure liquid compounds. This is
3.1 For custody transfer and other purposes, it is frequently
approximately true only for mixtures of hydrocarbons of the
necessary to convert a component analysis of light hydrocar-
same number of carbon atoms, and in the absence of diolefins
bon mixture from one basis (either gas-volume, liquid volume,
and acetylenic compounds.
or weight) to another.
1.4 The values stated in SI units are to be regarded as the
3.2 The component distribution data of light hydrocarbon
standard. The values given in parentheses are for information
mixtures can be used to calculate physical properties such as
only.
relative density, vapor-pressure, and calorific value. Consistent
1.5 This standard does not purport to address all of the
and accurate conversion data are extremely important when
safety concerns, if any, associated with its use. It is the
calculating vapor, liquid, or mass equivalence.
responsibility of the user of this standard to establish appro-
4. Procedure
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
4.1 To convert from the original to the desired basis,
multiply or divide the percent of each compound in the original
2. Source of Data
basis according to the schedule shown in Table 1. Perform the
2.1 The basic values for the relative density 15.6/15.6°C
calculation, using the corresponding factor indicated in Table
(60/60°F) of the pure compounds have been obtained from the
2. Carry at least one more significant figure in all of the
Thermodynamics Research Center, Texas A & M University,
calculations than the number of significant figures in the
except where otherwise noted. The values for methane, ethyl-
original analysis.
ene, and acetylene are not those of pure materials but are
NOTE 1—The factors or percentages can be multiplied by any constant
assumed to apply as a component of a liquid mixture.
number for convenience (such as moving the decimal) without changing
2.2 The conversion factors for 1 mL of ideal gas at 15.6°C
the end result.
(60°F) and 760 mm Hg to millilitres of liquid at 15.6°C (60°F)
4.2 Add the products or quotients obtained in accordance
have been calculated as follows: 1 mL gas at 15.6°C (60°F),
with 4.1.
760 mm Hg
4.3 Multiply the products or quotients obtained in accor-
L 5 ~273.16/288.72! 3 ~M/22414! (1)
dance with 4.1 by 100 divided by the sum of the products or
3 @1/~relative density!~0.99904!#
quotients. Round off the results so that the same number of
–5
significant figures is obtained in the final answer as was used in
4.2251 3 10 3 ~M/relative density!
the original analysis.
4.4 Add the percentages of the desired basis from 4.3 and
This practice is under the jurisdiction of ASTM Committee D-2 on Petroleum
distribute the round-off error (difference between the sum and
Products and Lubricantsand is the direct responsibility of Subcommittee D02.Hon
100 %) proportionately. Usually only the largest percentage
Liquefied Petroleum Gas.
Current edition approved Feb. 15, 1995. Published April 1995. Originally
will be changed in the final digit.
published as D 2421 – 65 T. Last previous edition D 2421 – 89.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
D 2421
TABLE 1 Conversion Factors Scheduled
5. Keywords
Factor Column in
5.1 analysis; liquefied petroleum gases; natural gas liquids
Original Basis Desired Basis Operation
Table 2
Gas-
...