ASTM_D_7996_-_15.pdf

Designation:D799615Standard Test Method forMeasuring Visible Spectrum of Asphaltenes in Heavy FuelOils and Crude Oils by Spectroscopy in a MicrofluidicPlatform1This standard is issued under the fixed designation D7996;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 measurement,either in thelaboratory or in the field,of visible spectra of asphaltenes andmaltenes in gas oil,diesel fuel,fuel oils,residual fuel oils,lubricating oil,bitumen,and crude oil using microfluidics andspectrographic techniques.21.2 These measurements can be related quantitatively to themass percent of asphaltenes present in the sample.1.3 The test method is limited to asphaltene-containing oilwith asphaltenes content less than 15%by mass.1.4 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.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.Referenced Documents2.1 ASTM Standards:3D3279 Test Method forn-Heptane InsolublesD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4175 Terminology Relating to Petroleum,PetroleumProducts,and LubricantsD4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsD6560 Test Method for Determination of Asphaltenes(Hep-tane Insolubles)in Crude Petroleum and Petroleum Prod-uctsE275 Practice for Describing and Measuring Performance ofUltraviolet and Visible Spectrophotometers3.Terminology3.1 Definitions:3.1.1 For definitions of terms used in this test method,seeTerminology D4175.3.1.2 absorbance,(A),nthe molecular property of a sub-stance that determines its ability to take up radiant energy,expressed by:A 5 log101 T!5 2log10T!(1)where T is the transmittance.3.1.2.1 DiscussionAbsorbance expresses the excess ab-sorption over that of a specified reference or standard.It isimplied that compensation has been affected for reflectancelosses,solvent absorption losses,and refractive effects,ifpresent,and that attenuation by scattering is small comparedwith attenuation by absorption.3.1.3 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.3.1.3.1 DiscussionIn this test method,the aromatic sol-vent is toluene and the paraffinic solvent is heptane.3.1.4 crude oil,na naturally occurring hydrocarbonmixture,generally in a liquid state,which may also includecompounds of sulfur,nitrogen,oxygen,metals,and otherelements.(Synonymcrude petroleum,crude.)3.1.5 dilution factor(f),nthe proportion of solvent in-crease made to reduce the concentration and thus the absor-bance of a solute,expressed by the ratio of the volume of thediluted solution to the volume of original solution containingthe same quantity of solute as the diluted solution.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 Dec.1,2015.Published February 2016.DOI:10.1520/D7996-15.2This method and the apparatus are covered by US Patent 8,269,961 andCanadian Patent 2,800,879.Interested parties are invited to submit informationregarding the identification of an alternative(s)to this patented item to ASTMInternational Headquarters.Your comments will receive careful consideration at ameeting of the responsible technical committee,1which you may attend.3For 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 3.1.6 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.3.1.7 transmittance,(T),nthe molecular property of asubstance that determines its transportability of radiant power,expressed by:T 5 PPo(2)where:P=the radiant power passing through the sample,andPo=the radiant power incident upon the sample.3.2 Definitions of Terms Specific to This Standard:3.2.1 concentration(c),nthe quantity of absorbing sub-stance in a solution in grams per litre.3.2.2 flow cell path length(b),nthe distance inmillimetres,measured in the dire