ASTM_D_7827_-_12.pdf

Designation:D782712Standard Test Method forMeasuring n-Heptane Induced Phase Separation ofAsphaltene from Heavy Fuel Oils as Separability Number byan Optical Device1This standard is issued under the fixed designation D7827;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 quantitative measurement,either in the laboratory or in the field,of how easily asphaltene-containing heavy fuel oils diluted in toluene phase separateupon addition of heptane.The result is a separability number(%).See also Test Method D7061.1.2 The test method is limited to asphaltene-containingheavy fuel oils.ASTM specification fuels that generally fallwithin the scope of this test method are Specification D396,Grade Nos.4,5,and 6,Specification D975,Grade No.4-D,and Specification D2880,Grade Nos.3-GT and 4-GT.Refineryfractions from which such blended fuels are made also fallwithin the scope of this test method.1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.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:2D396 Specification for Fuel OilsD975 Specification for Diesel Fuel OilsD2880 Specification for Gas Turbine Fuel OilsD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsD7061 Test Method for Measuring n-Heptane Induced PhaseSeparation of Asphaltene-Containing Heavy Fuel Oils asSeparability Number by an Optical Scanning Device3.Terminology3.1 Definitions:3.1.1 asphaltenes(rarely used in the singular),nin petro-leum technology,represent an oil fraction that is soluble in aspecified aromatic solvent but separates upon addition of anexcess of a specified paraffinic solvent.3.1.1.1 DiscussionIn this test method,the aromatic sol-vent is toluene and the paraffinic solvent is heptane.3.1.2 compatibility,nof crude oils or of heavy fuel oils,the ability of two or more crude oils or fuel oils to blendtogether within certain concentration ranges without evidenceof separation,such as the formation of multiple phases.3.1.2.1 DiscussionIncompatible heavy fuel oils or crudeoils,when mixed or blended,result in the flocculation orprecipitation of asphaltenes.Some oils may be compatiblewithin certain concentration ranges in specific mixtures,butincompatible outside those ranges.3.1.3 flocculation,nof asphaltenes from crude oils orheavy fuel oils,the aggregation of colloidally dispersed as-phaltenes into visibly larger masses that may or may not settle.3.1.4 peptization,nof asphaltenes in crude oils or heavyfuel oils,the dispersion of asphaltenes to produce a colloidaldispersion.3.1.5 stability reserve,nin petroleum technology,theproperty of an oil to maintain asphaltenes in a peptized stateand prevent flocculation of the asphaltenes.3.1.5.1 DiscussionAn oil with a low stability reserve islikely to undergo flocculation of asphaltenes when stressed(forexample,extended heated storage)or blended with a range ofother oils.Two oils each with a high stability reserve are likelyto maintain asphaltenes in a peptized state and not lead toflocculation when blended together.3.1.6 transmittance,nof light,the fraction of the incidentlight of a given wavelength that is not reflected or absorbed,but passes through a substance.3.2 Definitions of Terms Specific to This Standard:1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricants and is the direct responsibility ofSubcommittee D02.14 on Stability and Cleanliness of Liquid Fuels.Current edition approved Nov.1,2012.Published March 2013.DOI:10.1520/D7827-12.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.2.1 SEPView 6.1,nthe name of a proprietary computerprogram designed to allow automatic control of test andcalculations of the results in Test Method D7827.3.2.2 separability number,nin petroleum technology,thestandard deviation of the average transmittance,determined inthis test method,expressed as a percentage figure.3.2.2.1 DiscussionThe separability number estimates thestability reserve of the oil,where a high separability numberindicates that the oil has a low st