ASTM_D_2421_-_13.pdf

Designation:D242113Standard 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 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 C5and 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 numerically 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.1.4 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-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 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(60F)have been calculated as follows:For 1 mL gas at 15.6C(60F),101.325 kPa(760 mm Hg),L 5273.15/288.71!3M/22414!(1)31/relative density!30.999016!#4.2252310253M/relative density!5millilitres liquid at 15.6C60F!where:22414=calculated from V=nRT/P,n=1 g-mole,R=8314.472,T=273.15,andP=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 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.Consistentand 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 thecalculation,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 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.Originallyapproved 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 States1 4.2 Add the products or quotients 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.4.4 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-nent to force the sum total to 100%.NOTE1For sample calculations,see the Appendix.5.Keywords5.1 analysis;gas volume;interconversion;liquefied petro-leum gases;natural gas liquidsTABLE 1 Conversion Factors ScheduledOriginal BasisDesired BasisOperationFactor Column inTable 2Gas volumemassmultiply b