ASTM_D_2598_-_16.pdf

Designation:D259816Standard Practice forCalculation of Certain Physical Properties of LiquefiedPetroleum(LP)Gases from Compositional Analysis1This standard is issued under the fixed designation D2598;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 covers,by compositional analysis,theapproximate determination of the following physical charac-teristics of commercial propane,special-duty propane,com-mercial propane/butane mixtures,and commercial butane(cov-ered by Specification D1835):vapor pressure,relative density,and motor octane number(MON).1.1.1 This practice is not applicable to any product exceed-ing specifications for nonvolatile residues.(See Test MethodD2158.)1.1.2 For calculating motor octane number,this practice isapplicable only to mixtures containing 20%or less of propene.1.1.3 For calculated motor octane number,this practice isbased on mixtures containing only components shown in Table1.1.2 The values stated in SI units are to be regarded asstandard.1.2.1 Exceptions:1.2.1.1 Non-SI units in parentheses are given for informa-tion only.1.2.1.2 Motor octane number and relative density are givenin MON numbers and dimensionless units,respectively.2.Referenced Documents2.1 ASTM Standards:2D1267 Test Method for Gage Vapor Pressure of LiquefiedPetroleum(LP)Gases(LP-Gas Method)D1657 Test Method for Density or Relative Density of LightHydrocarbons by Pressure HydrometerD1835 Specification for Liquefied Petroleum(LP)GasesD2158 Test Method for Residues in Liquefied Petroleum(LP)GasesD2163 Test Method for Determination of Hydrocarbons inLiquefied Petroleum(LP)Gases and Propane/PropeneMixtures by Gas ChromatographyD2421 Practice for Interconversion of Analysis of C5andLighter Hydrocarbons to Gas-Volume,Liquid-Volume,orMass Basis2.2 Australian Liquefied Petroleum Gas Association Publi-cation:3Liquefied Petroleum Gas for Automotive Use Specification2.3 Gas Processors Suppliers Association:4GPSA Engineering Data Book,12th Edition,20043.Summary of Practice3.1 The composition of a sample of LP-gas is obtained byusing Test Method D2163 or other acceptable method.Fromthe analysis(expressed in liquid volume percent),the vaporpressure,relative density,and motor octane number of thesample may be determined.3.2 Conversion of a compositional analysis from mole,gasvolume,or weight basis to liquid volume is obtained by usingPractice D2421 or other suitable method.4.Significance and Use4.1 Vapor pressure is an important specification property ofcommercial propane,special duty propane,propane/butanemixtures,and commercial butane that assures adequatevaporization,safety,and compatibility with commercial appli-ances.Relative density,while not a specification criterion,isnecessary for determination of filling densities and custodytransfer.The motor octane number(MON)is useful in deter-mining the products suitability as a fuel for internal combus-tion engines.5.Calculation5.1 Calculated LP-Gas Vapor Pressure(see Test MethodD1267):1This 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 Oct.1,2016.Published October 2016.Originallyapproved in 1967.Last previous edition approved in 2012 as D2598 12.DOI:10.1520/D2598-16.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Available from Australian Liquefied Petroleum Gas Association Limited,ABN11002703951,30GeorgeStreet,RedfernNSW2016,http:/.au/site/4Available from Gas Processors SuppliersAssociation(GPSA),6526 E.60th St.,Tulsa,OK 74145,http:/www.gpsa.gpaglobal.org.*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 5.1.1 Calculate the partial gauge vapor pressure due to eachcomponent in the mixture as follows:Partial gauge vapor pressure5vp 3C!/100(1)where:vp=vapor pressure factor of specific component at 37.8 C(100 F)(see Table 1),andC=liquid volume percent of component in the mixture.5.1.2Add the partial gauge vapor pressures due to allcomponents,rounding to the nearest 7 kPa(1 psi).The total isreported as the LP-gas vapor pressure of the sample,kPa gaugeat 37.8 C(100 F).5.2 Calculated Relative Density(see Test Method D1657):5.2.1 Calculate the relative mass of each component in themixture as follows:Relative mass of component5sg 3C!/100(2)where:sg=relative density of the pure component at 15.6 C(60 F)(see Table 1),andC=liquid volume percent of component