ASTM_D_2002_-_93_scan.pdf

-ASTM D2002 93 O759530 0525353 725=Designation:D 2002-93 AMERICAN SOCIETY FOR TESTING AND hlATERIALS 1916 Rase St Ph:!adelphia,Pa 19103 Reprinted from the Annual Book of ASTM Standards.Copyright ASTM If not listed in the current combined index,will appear in the next edition.Standard Practice for Isolation of Representative Saturates Fraction from Low-Olefinic Petroleum Naphthas This standard is issued under the fixed designation D 2002;the number immediately following the designation indicates the year of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.A superscript epsilon(t)indicates an editorial change since the last revision or reapproval.1.Scope 1.1 This practice covers the isolation of a representative saturates fraction from depentanized hydrocarbon mixtures that distill below 221C(430F)and that contain less than 1 volume percent of olefinic hydrocarbons.1.2 The values stated in SI units are to be regarded as the standard.The values given in parentheses are for informa-tion only.1.3 This standard does not purport to address all o f the safety problems,is any,associated with its use.It is the responsibilily o f the user o f this standard to establish uppro-priate safety and health practices and determine the applicu-biliry o f regulatory limitations prior to ilse.Specific precau-tionary statements are given in Notes 1,2,and 3.2.Referenced Documents 2.1 ASTAf Standards:D 1319 Test Method for Hydrocarbon Types in Liquid Petroleum Products by Fluorescent Indicator Adsorp-tion2 3.Significance and Use 3.1 The determination of paraffins and naphthenes by the refractivity intercept method requires a sample free from olefins and aromatics.This practice is applicable for the isolation of saturates fractions from samples containing less than 1 volume%of olefinic hydrocarbons.4.Summary of Practice 4.1 A measured amount of sample is charged to the top of the giass column packed with fine activated silica gel.The adsorbed sample is then progressively desorbed with alcohol.In this process of adsorption and desorption the hydrocar-bons are separated according to their adsorption affinities.The saturated hydrocarbon components are least adsorbed and issue from the bottom of the silica gel column first.The total percolate collected prior to the elution of the yellow fluorescing olefinic marker is representative of the saturates in the sample.5.Apparatus 5.1 Adsorption Column,as shown in Fig.1,consisting of an eluent reservoir,a sample reservoir,and wide and narrow sections of a water-jacketed tubing.The column should be surrounded with a transparent protective shield when oper-ating at pressures in excess of 69 kPa(10 psi).The column shown in Fig.2 of this practice will give satisfactory performance if the charge does not exceed the capacity limits described in 7.3 of this test method.5.2 Receiver,graduated,of capacity sufficient to collect the total saturates as one fraction.5.3 Vibrator,for packing of silica gel.5.4 Pipet,or hypodermic syringe for charging samples.5.5 Ultraviolet Light Source,with radiation predomi-nantly at 3650 A.6.Reagents and Materials 6.1 Alcohol,ethyl or isopropyl.(Warning-See Note 1.)NOTE I:Warning-Flammable liquid.6.2 Fluorescent Indicator-Liquid dye mixture or stan-6.3 Pressuring Gas,nitrogen or air delivered to the top of 6.4 Silica Gel,149 to 74 pm(100 to 200 mesh).4 NOTE 2:Warning-Compressed gas.dard dyed gel?the column at a regulated pressure.(Warning-See Note 2.)7.Procedure 7.1 Prepare the apparatus and pack the adsorption column in accordance with 7.1.1 to 7.1.2 of this test method.Fluorescent indicator is required as a visual aid in making the cut between the separated saturates and olefin bands.Two forms of indicator are available for this purpoe.If the liquid fluorescent dye mixture is preferred,it should be added to the sample in a volume ratio of approximately 1 to 1000.If the standard dyed gel is preferred,it should be added to the adsorption column while it is being packed with silica gel.Approximately 0.25 mL of dyed gel added so that it is positioned near the top of the 10-mm section has proven satisfactory.7.1.1 Clean column and receiver with chromic-sulfuric acid,warm water,and acetone(Warning-See Note 3.)or alcohol,and dry them by evacuation.Lightly lubricate the stopcock at the bottom of the column and the receiver stopcock(but not the spherical joint of the sample reservoir This practice is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee W2.04 on Hydrocarbon Analysis.Current edition approved Aug.15,1993.Published October 1993.Originally published as D 2002-62 T.Last previous edition D 2002-9 I.*Annital Book oASTM Siandards,Vol 05.01.The standard dyed gel is available from UOP Process Div.,Organics Dept.,25 E.Algonquin Rd.,Des Plaines,IL60017-5017,by requesting RA Standard Dyed Gel,UOP Product No.675.Avail