ASTM_D_2421_-_18.pdf

Designation:D242118Standard 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 asstandard.The values given in parentheses after SI units areprovided for information only and are not considered standard.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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Source of Data2.1 The basic values for the relative density 15.6 C 15.6 C(60 F60 F)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 15.6 C(60 F)and 101.325 kPa(760 mm Hg)to millilitres of liquid at15.6 C(60 F)have been calculated as follows:For 1 mL gasat 15.6 C(60 F),101.325 kPa(760 mm Hg),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-mol,R=8314.472 mL kPa K1g-mol1,T=273.15 K,andP=101.325 kPa.2.3 Where ideal gas volumes have been measured at tem-peratures and pressures different from 15.6 C(60 F)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 original1This practice is under the jurisdiction of ASTM Committee D02 on PetroleumProducts,Liquid Fuels,and Lubricants and is the direct responsibility of Subcom-mittee D02.H0 on Liquefied Petroleum Gas.Current edition approved June 1,2018.Published November 2018.Originallyapproved in 1965.Last previous edition approved in 2013 as D2421 13.DOI:10.1520/D2421-18.*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 StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1 basis 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.4.2 Add the products or quotients obtained in accordancewith 4.1.4.3 Multiply the products or quotients obtained in acco