ASTM_D_2785_-_80_scan.pdf

AMERICAN NATIONAL ANSI/ASTM D 2785-80 STANDARD AMERICAN SOCIETV FOR TESTING AND MATERIALS 1916 Race St.,Phtladelphla,Pa.19103 A eprlntad from the Annual Book of ASTM Standards,Copyright ASTM If not listed in the current combined inde,will appear in the next edition.Standard Test Method for TRACE QUANTITIES OF TOT AL SULFUR(WICK BOLD AND BECKMAN COMBUSTION APPARATUS)1 This standard is issued under the fiiied designation D 27l!S:1he number immcdia1ely rollowi11g the dcsignalion indicalu 1he year or onginal adoption or.in the case of revision.the year orlas1 revision.A number in parcn1hcses indicates Che year of last reapproval.1.Scope I.I This method covers the determination of total sulfur primarily in the range from 2 to 25 ppm in volatile,normally liquid organic mate-rials(Note I).The method may be extended lo liquid materials with higher sulfur concentra-tion and to viscous liquids and solids by using appropriate.solvents.Samples should not con-tain more than I 00 ppm of halogens.2 ppm of barium.or 0.1 ppm of lead or appreciable ash-forming substances.NOTE I-For the determination of total sulfur in liquefied petroleum gases sec ASTM Method 0 2784.Test for Sulfur in Liquefied Petroleum Gases(Oxy-Hydrogen Burner or Lamp).2 Non:2-To anain the quantitative detectability.that the method is capable of,stringent techniques must be employed and all possible sources of sulfur contamination must be eliminated.Jn particular,cleaning agents.such as common household deter-gents which contain sulfates.should be avoided.2.Applicable Documents 2.1 A STM Standards.D 156 Test for Saybolt Color of Petroleum Products(Sayboll Chromcter Method)t D 270-API 2546 Sampling Petroleum and Petroleum Products:.D 1266 Sulfur in Petroleum Products(Lamp Method2 D 2784 Sulfur in Liquefied Petroleum Gases(OxyHydrogen Burner or Lam pf E l I Specification for Wire-Cloth Sieves for Testing Purposes4 3.Summary of Method 3.I The sample is burned in an oxy-hydro-gen atomizer burner.The oxides of sulfur are absorbed and oxidized lo sulfuric acid in a hydrogen peroxide solution.The sulfate ions are determined then by either of the following finishes:3.1.1 Barium PerchloraJe Titration-The sul-fate is titrated with barium perchlorate using a lhorin-methylene blue mixed indicator.3.1.2 Turbidimetric-The sulfate is precipi-tated as barium sulfate and the turbidity of a suspension of the precipitate is measured with a photometer.4.Significance 4.1 It is important to have the sulfur content of light liquid petroleum products al low enough concentrations to meet any applicable government regulations.The presence of sulfur may result in corrosion of metal surfaces.Sulfur may be poisonous to catalysts in subsequent processing.5.Apparatus 5.1 Oxy-hydrogen Combustion Assembly-The two types listed below are recommended.Any combustion apparatus giving equivalent results,however,is satisfactory.5.1.l Wickbold-rype Combustion Apparatus/as shown in Fig.l.1 This melhod is under the jurisdiction of ASTM Com-miltce D-2 on Pe1roleum ProductS ll!ld Lubricants.Current edition approved Aug.29,1980.Published Oc tober 1980.Originally published as D 278S-69 T.la.st previous edition D 2785-70(1975).,Annual Baok of ASTM Standards,Part 23.Annual Book of ASTM Standards.Part 24.Annual Book of ASTM Standards.Parts 14.18.26.30.and 41.Aailable from Fisher Scienlilic Co.Pittsburgh.Pa.15219.with an allstainless steel burner.or from Atlas lnstru mcnt Co.8902 E.I Ith S1.Tulsa.Okla.For the lauer.Hoke No.993 combination flow meter-valve am mblies should be substitutcti for those supplied.NOTICE:This standard has either been superseded and replaced by a new version or discontinued.Contact ASTM International(www.astm.org)for the latest information.5.l.2 Modified Beckman Burner Type Appa-ratus,;as shown in Fig.2.Each of the above types or apparatus shall consist of three parts:atomizer-bustion chamber.and ab-sorber with spray trap.A blowout safety port in the combustion chamber is desirable.The remainder of the apparatus shall consist of a suitable support stand with the necessary needle valves and flow meters for precise con-trol of oxygen,hydrogen,and vacuum.5.2 Safety Shield-A transparent shield shall be used to protect the operator in the event an ex.plosive mixture is formed in the combustion chamber.5.3 Vacuum Source,having a capacity of at least 1200 L/h.If a vacuum pump is used,it should be protected by a suitable trap.6.Purity of Reagents and Materials 6.1 Purity of Reagents-Reagent grade chemicals shall be used in all tests.Unless otherwise indicated,it is intended that all re-agents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society,where uch spec-ifications are available.;Other grades may be used,provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination.6.2 Purity of Water-References to water shall be understood to mean sulfate-f