1、Designation: D2421 13Standard Practice forInterconversion of Analysis of C5and 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 or, in the
2、 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 intercon-version of the analysis of C5an
3、d lighter hydrocarbon mixturesto gas-volume (mole), liquid-volume, or mass basis.1.2 The computation procedures described assume thatgas-volume percentages have already been corrected for non-ideality of the components as a part of the analytical process bywhich they have been obtained. These are nu
4、merically thesame as mole percentages.1.3 The procedure assumes the absence of nonadditivitycorrections for mixtures of the pure liquid compounds. This isapproximately true only for mixtures of hydrocarbons of thesame number of carbon atoms, and in the absence of diolefinsand acetylenic compounds.1.
5、4 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro
6、priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Source of Data2.1 The basic values for the relative density 15.6/15.6C(60/60F) of the pure compounds have been obtained fromTRC (formerly the Thermodynamics Research Center, andnow part of
7、NIST), except where otherwise noted. The valuesfor methane, ethylene, and acetylene are not those of purematerials but are assumed to apply as a component of a liquidmixture.2.2 The conversion factors for 1 mL of ideal gas at 15.6C(60F) and 101.325 kPa (760 mm Hg) to millilitres of liquid at15.6C (6
8、0F) have been calculated as follows:For 1 mL gas at 15.6C (60F), 101.325 kPa (760 mm Hg),L 5 273.15/288.71! 3 M/22414! (1)31/ relative density! 3 0.999016! #4.2252 310253 M/relative density!5millilitres liquid at 15.6C 60F!where:22414 = calculated from V=nRT/P,n = 1 g-mole,R = 8314.472,T = 273.15, a
9、ndP = 101.325 kPa.2.3 Where ideal gas volumes have been measured at tem-peratures and pressures different from 15.6C (60F) at101.325 kPa (760 mm Hg), they shall be corrected to theseconditions.3. Significance and Use3.1 For custody transfer and other purposes, it is frequentlynecessary to convert a
10、component analysis of light hydrocar-bon mixture from one basis (either gas volume, liquid volume,or mass) to another.3.2 The component distribution data of light hydrocarbonmixtures can be used to calculate physical properties such asrelative density, vapor-pressure, and calorific value. Consistent
11、and accurate conversion data are extremely important whencalculating vapor, liquid, or mass equivalence.4. Procedure4.1 To convert from the original to the desired basis,multiply or divide the percent of each compound in the originalbasis according to the schedule shown in Table 1. Perform thecalcul
12、ation, using the corresponding factor indicated in Table2. Carry at least one more significant figure in all of thecalculations than the number of significant figures in theoriginal analysis.4.1.1 The factors or percentages may be multiplied by anyconstant number for convenience (such as moving the
13、decimal)without changing the end result.1This practice is under the jurisdiction of ASTM Committee D02 on PetroleumProducts and Lubricants and is the direct responsibility of Subcommittee D02.H0on Liquefied Petroleum Gas.Current edition approved June 15, 2013. Published August 2013. Originallyapprov
14、ed in 1965. Last previous edition approved in 2002 as D2421 02 (2007).DOI: 10.1520/D2421-13.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.2 Add the products or quoti
15、ents obtained in accordancewith 4.1.4.3 Multiply the products or quotients obtained in accor-dance with 4.1 by 100 divided by the sum of the products orquotients. Round off the results so that the same number ofsignificant figures is obtained in the final answer as was used inthe original analysis.4
16、4 Add the percentages of the desired basis from 4.3 anddistribute the round-off error (difference between the sum and100 %) proportionately. If the sum total of the componentsdoes not equal 100 % after distributing the error, adjustment ofthe remainder shall be made to the largest percentage compo-
17、nent to force the sum total to 100 %.NOTE 1For sample calculations, see the Appendix.5. Keywords5.1 analysis; gas volume; interconversion; liquefied petro-leum gases; natural gas liquidsTABLE 1 Conversion Factors ScheduledOriginal Basis Desired Basis OperationFactor Column inTable 2Gas volume mass m
18、ultiply 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 3TABLE 2 Mass-Volume Data for Liquefied Petroleum Gases and Low Boiling HydrocarbonsAColumn 1 Column 2 Column 3Compound Molecu
19、lar MassLiquid Volume in mL of1 mL of ideal gas at15.6C (60F) and101.325 kPa (760 mm Hg)Relative Density 15.6/15.6C(60/60F) (Vacuum)MethaneB16.0425 0.0022594 0.3EthaneC30.0690 0.0035657 0.35630Ethyne (acetylene)B26.037 0.002601 0.423EthyleneB28.0532 0.0032 0.37DPropaneC44.0956 0.0036733 0.50721Prope
20、ne (propylene)C42.0797 0.0034020 0.52262Propadiene (allene)C40.065 0.002844 0.5953Propyne (methylacetylene)C40.065 0.002698 0.6273n-ButaneC58.1222 0.004204 0.58420Methyl propane (isobutane)C58.1222 0.0043630 0.562861-ButeneC56.106 0.003948 0.6004trans-2-ButeneC56.106 0.003887 0.6099cis-2-ButeneC56.1
21、06 0.003778 0.627532-Methyl propene (isobutylene)C56.106 0.003948 0.600441,2-ButadieneC54.090 0.003465 0.65951,3-ButadieneC54.090 0.003647 0.62671-Butyne (ethylacetylene)C54.090 0.003457 0.6610n-Pentane 72.1488 0.004833 0.630712-Methyl butane (isopentane) 72.1488 0.004876 0.62514Dimethyl propane (ne
22、opentane)C72.1488 0.005114 0.596101-Pentene 70.133 0.004559 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-Meth
23、yl-1,3-butadiene (isoprene) 68.117 0.004201 0.68511-trans-3-Pentadiene 68.117 0.004182 0.68831-cis-3-Pentadiene 68.117 0.004134 0.69621,2-Pentadiene 68.117 0.004125 0.6976ASources (except as noted):Column 1, Molecular MassD242102, GPA 214509, and GPSA Engineering Data Book (12th edition)Column 2, Li
24、quid VolumeCalculated from the relative density (column 3) and molecular mass (column 1), using Eq 1Column 3, Relative DensityProvided by TRC (NIST)BApparent values for dissolved gas at 15.6C (60F).CProperty of liquid phase measured at its saturation pressure at 15.6C (60F).DThe relative density of
25、ethylene is estimated and consistent with the historical value in D242195. Later revisions of D2421 used a theoretical, calculated value from GPA214500. Uncertainties in the equations of state used in the calculation for ethylene at typical pressures and temperatures of LPG caused GPA to later retra
26、ct that value.D2421 132APPENDIX(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 = 147
27、2.8Total 100.0 3008.3100.0/3008.3 = 0.03324Compound ProductMass,%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)Quo
28、tientEthane 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%byLiquidVolume, 15.6C(60F)Ethane 14.31 0.4975 = 7.12Propane 182.90 0.4975 = 90.99Isobutane 3.78 0.4975 = 1.88Total 99.99Remainder is assigned to large
29、st percentage component(100.00 99.99 = 0.01):Compound Remainder % by Liquid Volume,15.6C (60F)Ethane+0.017.12Propane 91.00Isobutane 1.88Total 100.00X1.3 Example 3:X1.3 Original basis: Liquid volumeDesired basis: Gas volumeD2421 133CompoundOriginalBasisLiquidVolume, %Operation(Table 1)FactorColumn 2(
30、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%byGasVolume(Ideal, 98.1 kPa,15.6C 1atm,60F)Propane 2722.3 0.004176 = 11.4n-Butane 20052.3 0.004176 = 83.7Isopentane 1169.0 0.00
31、4176 = 4.9Total 100.0SUMMARY OF CHANGESSubcommittee D02.H0 has identified the location of selected changes to this standard since the last issue(D2421 02(2007) that may impact the use of this standard.(1) Hydrocarbon data values were updated in Table 1, andexamples in the Appendix were corresponding
32、ly edited.(2) Note 1 became 4.1.1, and subsequent notes were renum-bered.(3) Subsection 4.4 was edited to include directions for consis-tent handling of rounding remainders.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentione
33、din this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and
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36、700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D2421 134
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