1、Designation: D 4929 04An American National StandardStandard Test Methods forDetermination of Organic Chloride Content in Crude Oil1This standard is issued under the fixed designation D 4929; the number immediately following the designation indicates the year oforiginal adoption or, in the case of re
2、vision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 These test methods cover the determination of organicchloride (above 1 g/g organically-bound chl
3、orine) in crudeoils, using either distillation and sodium biphenyl reduction ordistillation and microcoulometry.1.2 These test methods involve the distillation of crude oiltest specimens to obtain a naphtha fraction prior to chloridedetermination. The chloride content of the naphtha fraction ofthe w
4、hole crude oil can thereby be obtained. See Section 5regarding potential interferences.1.3 Test Method A covers the determination of organicchloride in the washed naphtha fraction of crude oil by sodiumbiphenyl reduction followed by potentiometric titration.1.4 Test Method B covers the determination
5、 of organicchloride in the washed naphtha fraction of crude oil byoxidative combustion followed by microcoulometric titration.1.5 Values expressed in acceptable SI units are to regardedas the standard. The preferred concentration units are micro-grams of chloride per gram of sample.1.6 This standard
6、 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
7、Standards:2D 86 Test Method for Distillation of Petroleum Products atAtmospheric PressureD 1193 Specification for Reagent WaterD 4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD 4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsD 6299 Practice for Applying S
8、tatistical Quality AssuranceTechniques to Evaluate Analytical Measurement SystemPerformance3. Summary of Test Method3.1 A crude oil distillation is performed to obtain thenaphtha cut at 204C (400F). The distillation method wasadapted from Test Method D86 for the distillation of petro-leum products.
9、The naphtha cut is washed with caustic,repeatedly when necessary, until all hydrogen sulfide is re-moved. The naphtha cut, free of hydrogen sulfide, is thenwashed with water, repeatedly when necessary, to removeinorganic halides (chlorides).3.2 There are two alternative test methods for determinatio
10、nof the organic chloride in the washed naphtha fraction, asfollows.3.2.1 Test Method A, Sodium Biphenyl Reduction andPotentiometryThe washed naphtha fraction of a crude oilspecimen is weighed and transferred to a separatory funnelcontaining sodium biphenyl reagent in toluene. The reagent isan additi
11、on compound of sodium and biphenyl in ethyleneglycol dimethyl ether. The free radical nature of this reagentpromotes very rapid conversion of the organic halogen toinorganic halide. In effect this reagent solubilizes metallicsodium in organic compounds. The excess reagent is decom-posed, the mixture
12、 acidified, and the phases separated. Theaqueous phase is evaporated to 25 to 30 mL, acetone is added,and the solution titrated potentiometrically.3.2.2 Test Method B, Combustion and MicrocoulometryThe washed naphtha fraction of a crude oil specimen is injectedinto a flowing stream of gas containing
13、 about 80 % oxygen and20 % inert gas, such as argon, helium, or nitrogen. The gas andsample flow through a combustion tube maintained at about800C. The chlorine is converted to chloride and oxychlorides,which then flow into a titration cell where they react with thesilver ions in the titration cell.
14、 The silver ions thus consumedare coulometrically replaced. The total current required toreplace the silver ions is a measure of the chlorine present inthe injected samples.3.2.3 The reaction occurring in the titration cell as chlorideenters is as follows:Cl21 Ag1 AgCl s! (1)1These test methods are
15、under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.03 on Elemental Analysis.Current edition approved Nov. 1, 2004. Published November 2004. Originallyapproved in 1989. Last previous edition approved in 1999 as D 492999
16、e1.2For 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.1*A Summary of Changes section appears at the end of this
17、standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.4 The silver ion consumed in the above reaction isgenerated coulometrically thus:Ag Ag11 e2(2)3.2.5 These microequivalents of silver are equal to thenumber of microequivalen
18、ts of titratable sample ion enteringthe titration cell.4. Significance and Use4.1 Organic chloride species are potentially damaging torefinery processes. Hydrochloric acid can be produced inhydrotreating or reforming reactors and the acid accumulates incondensing regions of the refinery. Unexpected
19、concentrationsof organic chlorides cannot be effectively neutralized anddamage can result. Organic chlorides are not known to benaturally present in crude oils and usually result from cleaningoperations at producing sites, pipelines, or tanks. It is importantfor the oil industry to have common metho
20、ds available for thedetermination of organic chlorides in crude oil, particularlywhen transfer of custody is involved.5. Interferences5.1 Test Method AOther titratable halides will also give apositive response. These titratable halides include HBr and HI.5.2 Test Method BOther titratable halides wil
21、l also give apositive response. These titratable halides include HBr and HI(HOBr and HOI do not precipitate silver). Since these oxyha-lides do not react in the titration cell, approximately 50 %microequivalent response is detected.5.2.1 This test method is applicable in the presence of totalsulfur
22、concentration of up to 10 000 times the chlorine level.6. Purity of Reagents6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the America
23、n Chemical Society,where such specifications are available.3Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.6.2 Purity of WaterUnless otherwise indicated, referencesto water
24、shall be understood to mean reagent water as definedby Type III of Specification D 1193.DISTILLATION AND CLEANUP PROCEDURE7. Apparatus7.1 Round-Bottom Boiling Flask, borosilicate, 1 L, singleshort neck with 24/40 outer ground-glass joint.7.2 Tee Adapter, borosilicate, 75 angle side-arm, 24/40ground-
25、glass joints.7.3 Thermometer, ASTM thermometer 2C (5 to 300C) or2F, (20F to 580F).7.3.1 Other temperature measuring devices, such as thermo-couples or resistance thermometers, may be used when thetemperature reading obtained by these devices is determined toproduce the same naphtha fraction that is
26、obtained whenmercury-in-glass thermometers are used.7.4 Thermometer Adapter, borosilicate, 24/40 inner ground-glass joint.7.5 Liebig Condenser, borosilicate, 300-mm length, 24/40ground-glass joints.7.6 Vacuum Take-Off Adapter, borosilicate, 105 anglebend, 24/40 ground-glass joints.7.7 Receiving Cyli
27、nder, borosilicate, 250-mL capacity,24/40 outer ground-glass joint.7.8 Wire Clamps, for No. 24 ground-glass joints, stainlesssteel.7.9 Receiver Flask, for ice bath, 4 L.7.10 Copper Tubing, for heat exchanger to cool condenserwater, 6.4-mm outside diameter, 3-m length.7.11 Electric Heating Mantle, Gl
28、as-Col Series 0, 1-L size,140-W upper heating element, 380-W lower heating element.7.12 Variacs, 2, for temperature control of upper and lowerheating elements, 120 V, 10 amps.8. Reagents and Materials8.1 Acetone, chloride-free. (WarningExtremely flam-mable, can cause flash fires. Health hazard.)8.2
29、Caustic Solution,1M potassium hydroxide(WarningCan cause severe burns to skin.) prepared indistilled/deionized water.8.3 Distilled/Deionized Water.8.4 Filter Paper, Whatman No. 41 or equivalent.8.5 Stopcock Grease.4,58.6 Toluene, chloride-free. (WarningFlammable. Healthhazard.)9. Sampling9.1 Obtain
30、a test unit in accordance with Practice D 4057 orD 4177. To preserve volatile components, which are in somesamples, do not uncover samples any longer than necessary.Samples should be analyzed as soon as possible, after takingfrom bulk supplies, to prevent loss of organic chloride orcontamination due
31、 to exposure or contact with sample con-tainer. (WarningSamples that are collected at temperaturesbelow room temperature may undergo expansion and rupturethe container. For such samples, do not fill the container to thetop; leave sufficient air space above the sample to allow roomfor expansion.)9.2
32、If the test unit is not used immediately, then thoroughlymix in its container prior to taking a test specimen. Some testunits can require heating to thoroughly homogenize.3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the te
33、sting of reagents notlisted by the American Chemical Society, see Annual Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.4The sole source of supply of the stop-cock gr
34、ease known to the committee atthis time is Dow Corning silicone, available from Dow Corning Corporation,Corporate Center, PO Box 994, Midland, MI.5If you are aware of alternative suppliers, please provide this information toASTM International Headquarters. Your comments will receive careful consider
35、-ation at a meeting of the responsible technical committee,1which you may attend.D4929042(WarningWhen heating is required, care should be taken sothat no organic chloride containing hydrocarbons are lost.)10. Preparation of Apparatus10.1 Clean all glassware by rinsing successively with tolu-ene and
36、acetone. After completing the rinse, dry the glasswareusing a stream of dry nitrogen gas. Obtain and record themasses of the round-bottom flask and receiving cylinder.Assemble the glass distillation apparatus using stopcock greaseto seal all joints and wire clamps to prevent loosening of thejoints.
37、Adjust the thermometer position within the adapter teesuch that the lower end of the capillary is level with the highestpoint on the bottom of the inner wall of the adapter tee sectionthat connects to the condenser.NOTE 1A diagram illustrating the appropriate positioning of thethermometer can be fou
38、nd in Test Method D86.10.2 Form the copper tubing into a coil to fit inside thereceiver flask, leaving room in the center of the flask for thereceiving cylinder. With the PVC tubing, connect one end ofthe copper coil to the water source, and connect the other endof the coil to the lower fitting of t
39、he Liebig condenser coolingjacket. Connect the upper condenser fitting to the water drain.Fill the receiver flask with an ice/water mixture, and turn on thewater. Maintain the temperature of the condenser below 10C.11. Procedure11.1 Add a 500-mL crude oil test specimen to tared roundbottom flask. Ob
40、tain and record the mass of the crude oil-filledflask to the nearest 0.1 g. Connect the flask to the distillationapparatus. Place the heating mantle around the flask, andsupport the heating mantle/flask from the bottom. Connect theheating mantle to the variacs. Turn on the variacs and start thedisti
41、llation. During the distillation, adjust the variac settings togive a distillation rate of approximately 5 mL/min. Continuethe distillation until a thermometer reading of 204C (400F) isattained. When the temperature reaches 204C (400F), end thedistillation by first disconnecting and removing the rec
42、eivingcylinder. After the receiving cylinder has been removed, turnoff the variacs and remove the heating mantle from the flask.Obtain and record the mass of the receiving cylinder anddistillate.11.1.1 The precision and bias statements were determinedusing mercury-in-glass thermometers only. Therefo
43、re, whenalternate temperature measuring devices are used, the cut-offtemperature so obtained shall be that which will produce anaphtha cut similar to what would be yielded when mercury-in-glass thermometers are used. Such alternate temperaturemeasuring devices shall not be expected to exhibit the sa
44、metemperature lag characteristics as mercury-in-glass thermom-eters.11.2 Transfer the naphtha fraction from the receiving cylin-der to the separatory funnel. Using the separatory funnel, washthe naphtha fraction three times with equal volumes of thecaustic solution (1 M KOH). Follow the caustic wash
45、 with awater wash, again washing three times with equal volumes.The caustic wash removes hydrogen sulfide, while the waterwash removes traces of inorganic chlorides either originallypresent in the crude or from impurities in the caustic solution.After the washings are complete, filter the naphtha fr
46、action toremove residual freestanding water. Store the naphtha fractionin a clean glass bottle. This naphtha fraction can now beanalyzed for organic chlorides by either sodium biphenyl orcombustion/microcoulometric techniques.11.3 Measure the density of the crude oil specimen and thenaphtha fraction
47、 by obtaining the mass of 10.0 mL (using a10-mL volumetric flask) of each to the nearest 0.1 g.12. Calculation12.1 Calculate naphtha fraction as follows:f 5 Mn/Mc(3)where:f = mass fraction of naphtha collected,Mn= mass of naphtha collected, andMc= mass of crude oil specimen.12.2 Calculate the densit
48、y as follows:Density, g/mL 5 m/v (4)where:m = mass of sample specimen, g, andv = volume of sample specimen, mL.TEST METHOD ASODIUM BIPHENYLREDUCTION AND POTENTIOMETRY13. Apparatus13.1 ElectrodesThe cleaning and proper care of elec-trodes are critical to the accuracy of this test. Manufacturersinstru
49、ctions for the care of electrodes shall be followed.13.1.1 Glass, general purpose.5,6When glass electrodes arein continuous use, weekly cleaning with chrome-sulfuric acid(WarningStrong oxidizer; can cause severe burns; recog-nized carcinogen), or other strongly oxidizing cleaning solu-tion, is recommended.13.1.2 Silver-Silver Chloride, billet-type.13.2 Titrator, potentiometric. The titrator is equipped with a5-mL or smaller buret and a magnetic stirring motor.14. Reagents and Materials14.1 Acetone, chloride-free. (WarningExtremely flam-mable, can ca
