1、Designation: D2421 13D2421 18Standard Practice forInterconversion of Analysis of C5 and Lighter Hydrocarbonsto Gas-Volume, Liquid-Volume, or Mass Basis1This standard is issued under the fixed designation D2421; the number immediately following the designation indicates the year oforiginal adoption o
2、r, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This practice describes the procedure for the interconversion of the analysis
3、 of C5 and lighter hydrocarbon mixtures togas-volume (mole), liquid-volume, or mass basis.1.2 The computation procedures described assume that gas-volume percentages have already been corrected for nonideality ofthe components as a part of the analytical process by which they have been obtained. The
4、se are numerically the same as molepercentages.1.3 The procedure assumes the absence of nonadditivity corrections for mixtures of the pure liquid compounds. This isapproximately true only for mixtures of hydrocarbons of the same number of carbon atoms, and in the absence of diolefins andacetylenic c
5、ompounds.1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.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, a
6、ssociated with its use. It is the responsibilityof the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine theapplicability of regulatory limitations prior to use.1.6 This international standard was developed in accordance with intern
7、ationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Source of Data2.1 The basic values for the relat
8、ive density 15.6/15.6C15.6 C (60/60F)15.6 C (60 F60 F) of the pure compounds havebeen obtained from TRC (formerly the Thermodynamics Research Center, and now part of NIST), except where otherwise noted.The values for methane, ethylene, and acetylene are not those of pure materials but are assumed to
9、 apply as a component of a liquidmixture.2.2 The conversion factors for 1 mL 1 mL of ideal gas at 15.6C (60F) and 101.325 kPa (760 mm 15.6 C (60 F) and101.325 kPa (760 mm Hg) to millilitres of liquid at 15.6C (60F)15.6 C (60 F) have been calculated as follows:1 This practice is under the jurisdictio
10、n of ASTM Committee D02 on Petroleum Products Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.H0 on Liquefied Petroleum Gas.Current edition approved June 15, 2013June 1, 2018. Published August 2013November 2018. Originally approved in 1965. Last previous ed
11、ition approved in 20022013as D2421 02 (2007).D2421 13. DOI: 10.1520/D2421-13.10.1520/D2421-18.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically poss
12、ible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCop
13、yright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1For 1 mL gas at 15.6C (60F), 101.325 kPa (760 mm For 1 mL gas at 15.6 C (60 F), 101.325 kPa (760 mm Hg),L 5273.15/288.71!3M/22414! (1)31/relative density!30.999016!#4.2252310253M/relative d
14、ensity!5millilitres liquid at 15.6C 60F!L 5273.15 K/288.71!3M/22414! (1)31/relative density!30.999016!#4.2252310253M/relative density!5millilitres liquid at 15.6 C60 F!where:L = calculated liquid volume, mL,M = molecular weight, g-mol,22414 = calculated from V=nRT/P,n = 1 g-mole,n = 1 g-mol,R = 8314
15、472,R = 8314.472 mL kPa K1 g-mol1,T = 273.15, andT = 273.15 K, andP = 101.325 kPa.2.3 Where ideal gas volumes have been measured at temperatures and pressures different from 15.6C (60F) at 101.325 kPa(760 mm 15.6 C (60 F) at 101.325 kPa (760 mm Hg), they shall be corrected to these conditions.3. Si
16、gnificance and Use3.1 For custody transfer and other purposes, it is frequently necessary to convert a component analysis of light hydrocarbonmixture 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
17、 calculate physical properties such as relativedensity, vapor-pressure, and calorific value. Consistent and accurate conversion data are extremely important when calculatingvapor, liquid, or mass equivalence.4. Procedure4.1 To convert from the original to the desired basis, multiply or divide the pe
18、rcent of each compound in the original basisaccording to the schedule shown in Table 1. Perform the calculation, using the corresponding factor indicated in Table 2. Carryat least one more significant figure in all of the calculations than the number of significant figures in the original analysis.4
19、1.1 The factors or percentages may be multiplied by any constant number for convenience (such as moving the decimal)without changing the end result.4.2 Add the products or quotients obtained in accordance with 4.1.4.3 Multiply the products or quotients obtained in accordance with 4.1 by 100 divided
20、 by the sum of the products or quotients.Round off the results so that the same number of significant figures is obtained in the final answer as was used in the originalanalysis.TABLE 1 Conversion Factors ScheduledOriginal Basis Desired Basis Operation Factor Column inTable 2Gas volume mass multiply
21、 by 1Gas volume liquid volume multiply by 2Mass gas volume divide by 1Mass liquid volume divide by 3Liquid volume gas volume divide by 2Liquid volume mass multiply by 3D2421 1824.4 Add the percentages of the desired basis from 4.3 and distribute the round-off error (difference between the sum and 10
22、0 %)proportionately. If the sum total of the components does not equal 100 % after distributing the error, adjustment of the remaindershall be made to the largest percentage component to force the sum total to 100 %.NOTE 1For sample calculations, see the Appendix.5. Keywords5.1 analysis; gas volume;
23、 interconversion; liquefied petroleum gases; natural gas liquidsTABLE 2 Mass-Volume Data for Liquefied Petroleum Gases and Low Boiling HydrocarbonsAColumn 1 Column 2 Column 3Compound Molecular MassLiquid Volume in mL of1 mL of ideal gas at15.6C (60F)15.6 C (60 F) and101.325 kPa (760 mm Hg)Relative D
24、ensity 15.6/15.6C15.6 C 15.6 C(60/60F)(60 F 60 F) (Vacuum)MethaneB 16.0425 0.0022594 0.3EthaneC 30.0690 0.0035657 0.35630Ethyne (acetylene)B 26.037 0.002601 0.423EthyleneB 28.0532 0.0032 0.37DPropaneC 44.0956 0.0036733 0.50721Propene (propylene)C 42.0797 0.0034020 0.52262Propadiene (allene)C 40.065
25、0.002844 0.5953Propyne (methylacetylene)C 40.065 0.002698 0.6273n-ButaneC 58.1222 0.004204 0.58420Methyl propane (isobutane)C 58.1222 0.0043630 0.562861-ButeneC 56.106 0.003948 0.6004trans-2-ButeneC 56.106 0.003887 0.6099cis-2-ButeneC 56.106 0.003778 0.627532-Methyl propene (isobutylene)C 56.106 0.0
26、03948 0.600441,2-ButadieneC 54.090 0.003465 0.65951,3-ButadieneC 54.090 0.003647 0.62671-Butyne (ethylacetylene)C 54.090 0.003457 0.6610n-Pentane 72.1488 0.004833 0.630712-Methyl butane (isopentane) 72.1488 0.004876 0.62514Dimethyl propane (neopentane)C 72.1488 0.005114 0.596101-Pentene 70.133 0.004
27、559 0.6500trans-2-Pentene 70.133 0.004537 0.6531cis-2-Pentene 70.133 0.004490 0.6602-Methyl-1-butene 70.133 0.004519 0.65573-Methyl-1-butene 70.133 0.004672 0.63422-Methyl-2-butene 70.133 0.004461 0.6643Cyclopentane 70.133 0.003949 0.75032-Methyl-1,3-butadiene (isoprene) 68.117 0.004201 0.68511-tran
28、s-3-Pentadiene 68.117 0.004182 0.68831-cis-3-Pentadiene 68.117 0.004134 0.69621,2-Pentadiene 68.117 0.004125 0.6976A Sources (except as noted):Column 1, Molecular MassD242102, GPA 214509, and GPSA Engineering Data Book (12th edition)Column 2, Liquid VolumeCalculated from the relative density (column
29、 3) and molecular mass (column 1), using Eq 1Column 3, Relative DensityProvided by TRC (NIST)B Apparent values for dissolved gas at 15.6C (60F).15.6 C (60 F).C Property of liquid phase measured at its saturation pressure at 15.6C (60F).15.6 C (60 F).D The relative density of ethylene is estimated an
30、d consistent with the historical value in D2421D2421 95.95. Later revisions of D2421 used a theoretical, calculatedvalue from GPA214500.2145 00. Uncertainties in the equations of state used in the calculation for ethylene at typical pressures and temperatures of LPG caused GPAto later retract that v
31、alue.D2421 183APPENDIX(Nonmandatory Information)X1. EXAMPLESX1.1 Example 1:X1.1 Original basis: Gas volume or mole, %Desired basis: MassCompoundOriginalBasisMole,%Operation(Table 1)FactorColumn1(Table2)ProductMethane 33.3 16.0425 = 534.2Ethane 33.3 30.0690 = 1001.3Propane 33.4 44.0956 = 1472.8Total
32、100.0 3008.3100.0/3008.3 = 0.03324Compound Product Mass,%Methane 534.2 0.03324 = 17.8Ethane 1001.3 0.03324 = 33.3Propane 1472.8 0.03324 = 48.9Total 100.0X1.2 Example 2:X1.2 Original basis: MassDesired basis: Liquid volumeCompoundOriginalBasisMass,%Operation(Table 1)FactorColumn 3(Table 2)QuotientEth
33、ane 5.10 0.35630 = 14.31Propane 92.77 0.50721 = 182.90Isobutane 2.13 0.56286 = 3.78Total 100.00 200.99100.00/200.99 = 0.4975Compound Quotient% by LiquidVolume, 15.6C(60F)15.6 C(60 F)Ethane 14.31 0.4975 = 7.12Propane 182.90 0.4975 = 90.99Isobutane 3.78 0.4975 = 1.88Total 99.99Remainder is assigned to
34、 largest percentage component (100.00 99.99 = 0.01):Compound Remainder % by Liquid Volume,15.6C (60F)Compound Remainder % by Liquid Volume,15.6 C (60 F)Ethane+0.017.12Propane 91.00Isobutane 1.88Total 100.00D2421 184X1.3 Example 3:X1.3 Original basis: Liquid volumeDesired basis: Gas volumeCompoundOri
35、ginalBasisLiquidVolume, %Operation(Table 1)FactorColumn 2(Table 2)QuotientPropane 10.0 0.0036733 = 2722.3n-butane 84.3 0.004204 = 20052.3Isopentane 5.7 0.004876 = 1169.0Total 100.00 23943.6100.0/23943.6 = 0.004176Compound Quotient% by GasVolume(Ideal, 98.1 kPa,15.6C15.6 C1atm, 60F)60 F)Propane 2722.
36、3 0.004176 = 11.4n-Butane 20052.3 0.004176 = 83.7Isopentane 1169.0 0.004176 = 4.9Total 100.0SUMMARY OF CHANGESSubcommittee D02.H0 has identified the location of selected changes to this standard since the last issue(D2421 02D2421 13(2007) that may impact the use of this standard. (Approved June 1, 2
37、018.)(1) Hydrocarbon dataThe terms valuesL and M were updated indefined for Table 1Eq 1, and examples in the Appendix werecorrespondingly edited(2) Note 1 became 4.1.1, and subsequent notes were renumbered.(3) Subsection 4.4 was edited to include directions for consistent handling of rounding remain
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