ASTM_D_2779_-_92_2012.pdf

Designation:D277992(Reapproved 2012)Standard Test Method forEstimation of Solubility of Gases in Petroleum Liquids1This standard is issued under the fixed designation D2779;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.Scope1.1 This test method covers the estimation of the equilib-rium solubility of several common gases encountered in theaerospace industry in hydrocarbon liquids.These includepetroleum fractions with densities in the range from 0.63 to0.90 at 288 K(59F).The solubilities can be estimated over thetemperature range 228 K(50F)to 423 K(302F).1.2 This test method is based on the Clausius-Clapeyronequation,Henrys law,and the perfect gas law,with empiri-cally assigned constants for the variation with density and foreach gas.1.3 The values stated in SI units are to be regarded as thestandard.The values in parentheses are for information only.1.4 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.Referenced Documents2.1 ASTM Standards:2D1298 Test Method for Density,Relative Density(SpecificGravity),or API Gravity of Crude Petroleum and LiquidPetroleum Products by Hydrometer Method3.Terminology3.1 Definitions:3.1.1 Bunsen coeffcientthe solubility of a gas expressedas the volume,reduced to 273 K(32F)and 101.3 kPa(1 atm),dissolved by 1 volume of liquid at the specified temperatureand 101.3 kPa.3.1.2 Henrys lawthe principle that the ratio of partialpressure to mole fraction of gas in solution is a constant.3.1.2.1 DiscussionIn non-ideal systems the fugacity isused to replace the pressure,but the systems within the scopeof this test method can be considered ideal within the limits ofthe accuracy statement.3.1.3 Ostwald coeffcientthe solubility of a gas expressedas the volume of gas dissolved per volume of liquid when thegas and liquid are in equilibrium at the specified partialpressure of gas and at the specified temperature.3.2 Symbols:d=density of the liquid at 288 K(59F),kg/L,T=specified temperature,K,Lo=Ostwald coefficient at 273 K for a liquid ofd=0.85,L=Ostwald coefficient at T for a liquid ofd=0.85,Lc=Ostwald coefficient at T for a liquid of thespecified density,p=pressure of the gas,or mixed gases,MPa,pv=vapor pressure of the liquid at the specifiedtemperature,MPa,p1,p2.pi=partial pressures of the gases in a mixture,MPa,G=solubility,mg/kg,B=Bunsen coefficient at the specified d,p,and T,X=mole fraction of gas in equilibrium solution,Lm,Bm=coefficients for mixture of gases,M=molecular weight of the gas,g/mol,Ml=molecular weight of the liquid,g/mol,H=Henrys law constant,MPa,andC=molarity,kg mol/m3.4.Summary of Test Method4.1 Correlations have been established by the NationalAeronautics and Space Administration(formerly NationalAdvisory Committee onAeronautics)in NACATechnical Note3276(1956)3Their work was extended to include most of thedata published since that time,and extrapolated by semi-empirical methods into regions where no data are available.4.2 The only data required are the density of liquid at 288 K(59F)and the nature of the gas.These are used in the1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.L0.07 on Engineering Sciences of High Performance Fluids and Solids(Formally D02.1100).Current edition approved April 15,2012.Published April 2012.Originallyapproved in 1969.Last previous edition approved in 2007 as D277992(2007).DOI:10.1520/D2779-92R12.2For 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 National Aeronautics and Space Administration,Washington,DC.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 equations,with the specific constant for the gas from Table 1,or with Fig.1,to estimate the Ostwald coefficient.5.Significance and Use5.1 Knowledge of gas solubility is of extreme importance inthe lubrication of gas compressors.It is believed to be asubstantial factor in boundary lubrication,where the suddenrelease of dissolved gas may cause cavitation erosion,or evencollapse of the fluid film.In hydraulic and seal oils,gasdissolved at high pressure can cause excessive foaming onrelease of the pressure.In aviation oils and fuels,the differencein pressure between take-off and cruise altitude can causefoaming out of the storage vessels and interrupt flow to thepumps.6