ASTM_D_6920_-_13.pdf

Designation:D692013Standard Test Method forTotal Sulfur in Naphthas,Distillates,ReformulatedGasolines,Diesels,Biodiesels,and Motor Fuels byOxidative Combustion and Electrochemical Detection1This standard is issued under the fixed designation D6920;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 test method covers the determination of total sulfurin liquid hydrocarbons,boiling in the range from approxi-mately 25 to 400C,with viscosities between approximately0.2 and 10 cSt(mm/S)at room temperature.This test methodis applicable to naphthas,distillates,and motor fuels such asgasolines,reformulated gasolines,gasohols,diesels and bio-diesels containing approximately 1 to 100 mg/kg total sulfur ingasoline type products,and approximately 1 to 40 mg/kg sulfurin diesel type products.1.2 The detector response for this technique within thescope of this test method is linear with sulfur concentration.1.3 Based on interlaboratory study,the pooled limit ofquantitation of this test method is 3 mg/kg for gasoline and0.5 mg/kg for diesel samples.1.4 This test method meets the U.S.EPA requirements formeasuring sulfur in ultra low sulfur diesel fuels by thedesignated Test Method D6428,as published in the U.S.Federal Register 80.520(a)(1).1.5 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.6 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.For specific hazardstatements,see Sections 8 and 9.2.Referenced Documents2.1 ASTM Standards:2D4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsD6299 Practice for Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System PerformanceD6428 Test Method for Total Sulfur in Liquid AromaticHydrocarbons and Their Derivatives by Oxidative Com-bustion and Electrochemical Detection(Withdrawn2006)3D6792 Practice for Quality System in Petroleum Productsand Lubricants Testing Laboratories2.2 U.S.Federal Register:80.520(a)(1)Vol.68,No.10043.Terminology3.1 Definitions:3.1.1 oxidative combustion,nprocess in which a sampleundergoes combustion in an oxygen rich environment attemperatures greater than 650C and compounds decompose tocarbon dioxide,water,and elemental oxides.3.1.2 quartz combustion tube devitrification,nprocess inwhich samples containing alkali-metals(that is,elements fromthe Periodic Table Group IA,for example,sodium,potassium,etc.)or alkaline earth(that is,elements from the Periodic Table1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricants and is the direct responsibility ofSubcommittee D02.03 on Elemental Analysis.Current edition approved Sept.15,2013.Published September 2013.Originallyapproved in 2003.Last previous edition approved in 2007 as D6920 07.DOI:10.1520/D6920-13.2For 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.3The last approved version of this historical standard is referenced onwww.astm.org.4Available from U.S.Government Printing Office Superintendent of Documents,732 N.Capitol St.,NW,Mail Stop:SDE,Washington,DC 20401.*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 Group IIA,for example,calcium,magnesium,etc.)will causequartz to devitrify(that is,become milky white and brittle)atelevated temperatures.3.1.2.1 DiscussionIt is suggested that the quartz combus-tion tube temperature be kept 900C)where oxygen is introduced.Sulfur compounds,present in the specimen are converted to sulfur dioxide(SO2).Sulfur dioxide is reacted with the sensing electrode in a3-electrode electrochemical cell.This reaction produces ameasurable current that is directly proportional to the amountof sulfur in the original sample material.The reactions thatoccur are as follows:Combustion:R-S+O2.900CCO2+H2O+SO2+ox-idesDetection:SO2+2H2OElectrolyteH2SO4+2H+2e5.Significance and Use5.1 All sulfur present in petroleum products is converted tosulfur oxides upon combustion,which is a significant pollutantof the atmosphere.This test method can be used to monitor thetotal sulfur levels in these fuels.NOTE1Virtually all sulfur compounds will be detected by thist