ASTM_D_6470_-_99_2015.pdf

Designation:D647099(Reapproved 2015)Standard Test Method forSalt in Crude Oils(Potentiometric Method)1This standard is issued under the fixed designation D6470;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 determination of salt incrude oils.For the purpose of this test method,salt is expressedas%(m/m)NaCl(sodium chloride)and covers the range from0.0005%to 0.15%(m/m).1.2 The limit of detection is 0.0002%(m/m)for salt(asNaCl).1.3 The test method is applicable to nearly all of the heavierpetroleum products,such as crude oils,residues,and fuel oils.It may also be applied to used turbine oil and marine diesel fuelto estimate seawater contamination.Water extractable salts,originating from additives present in oils,are codetermined.1.4 The values stated in SI units are to be regarded as thestandard.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:2D329 Specification for AcetoneD770 Specification for Isopropyl AlcoholD843 Specification for Nitration Grade XyleneD1193 Specification for Reagent WaterD4006 Test Method for Water in Crude Oil by DistillationD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsD4377 Test Method for Water in Crude Oils by Potentiomet-ric Karl Fischer TitrationD4928 Test Method for Water in Crude Oils by CoulometricKarl Fischer TitrationE200 Practice for Preparation,Standardization,and Storageof Standard and Reagent Solutions for Chemical Analysis3.Summary of Test Method3.1 After homogenizing the crude oil with a mixer,aweighed aliquot is dissolved in xylene at 65 C and extractedwith specified volumes of alcohol,acetone,and water in anelectrically heated extraction apparatus.A portion of theaqueous extract is analyzed for total halides by potentiometrictitration.4.Significance and Use4.1 A knowledge of water extractable inorganic halides inoil is important when deciding whether or not the oils needdesalting.Excessive halide,especially in crude oil,frequentlyresults in higher corrosion rates in refining units.5.Apparatus5.1 Extraction Apparatus,made of borosilicate glass,con-forming to the dimensions given in Fig.1,and consisting of thefollowing component parts:5.1.1 Boiling Flask,500 mL capacity.5.1.2 Hopkins Reflux Condenser,having a vapor outletconnected by a rubber tube to an outside vent or to a suctionhood.5.1.3 Thistle Tube,approximately 70 mL capacity,with aline to indicate approximately the 50 mL level.5.1.4 Heating Tube,containing a chimney for increasingconvection in the liquid.5.1.5 Heating Coil,250 W,consisting of a suitable gage ofNichrome wire.5.1.6 Rheostat,of suitable resistance and capacity,forregulating the heater.5.2 Safety Shield,colorless safety glass,or equivalent,to bemounted in front of the extraction apparatus(see 5.1).5.3 Sampling Tube,glass,length approximately 600 mm,I.D.approximately 5 mm,with a bulb having a volume of100 mL,or more,and drawn out at one end to an opening ofinside diameter(I.D.)2 mm to 3 mm.A pipette with cut-off tipmakes a suitable sample tube.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricantsand is the direct responsibility ofSubcommittee D02.03 on Elemental Analysis.Current edition approved April 1,2015.Published May 2015.Originallyapproved in 1999.Last previous edition approved in 2010 as D6470 99(2010).DOI:10.1520/D6470-99R15.2For 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 5.4 Potentiometric Titration Equipment,with a measuringaccuracy of 62 mV,or better,provided with a silver indicatingand a glass reference electrode and 10 mL burette,preferablypiston type.If an automatic titrator is used,this shall be capableof adding fixed increments of titrant(see 9.3.3.2).5.5 Magnetic Stirrer,with polytetrafluoroethylene(PTFE)-coated stirring bar.5.6 Homogenizer.A mixer with counter-rotating bladesoperating at approximately 3000 r min(50/s)is usually suit-able for homogenization of samples up to 500 mL.Otherdesigns can also be used provided the performance conforms tothe requirements described in Annex A1.5.7 Oven,explosion-proof,temperature 65 C 6 5 C.5.8 Filter