1、Designation: D4929 15D4929 15aStandard Test Methods forDetermination of Organic Chloride Content in Crude Oil1This standard is issued under the fixed designation D4929; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of la
2、st 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 These test methods cover the determination of organic chloride (above 1 g/g organically-bound chlorine) in crude oils,u
3、sing either distillation and sodium biphenyl reduction or distillation and microcoulometry.1.2 These test methods involve the distillation of crude oil test specimens to obtain a naphtha fraction prior to chloridedetermination. The chloride content of the naphtha fraction of the whole crude oil can
4、thereby be obtained. See Section 5 regardingpotential interferences.1.3 Test MethodAcovers the determination of organic chloride in the washed naphtha fraction of crude oil by sodium biphenylreduction followed by potentiometric titration.1.4 Test Method B covers the determination of organic chloride
5、 in the washed naphtha fraction of crude oil by oxidativecombustion followed by microcoulometric titration.1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.The preferred concentration units are micrograms of chloride per gr
6、am of sample.1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. R
7、eferenced Documents2.1 ASTM Standards:2D86 Test Method for Distillation of Petroleum Products and Liquid Fuels at Atmospheric PressureD1193 Specification for Reagent WaterD4057 Practice for Manual Sampling of Petroleum and Petroleum ProductsD4177 Practice for Automatic Sampling of Petroleum and Petr
8、oleum ProductsD6299 Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measure-ment System Performance3. Summary of Test Method3.1 Acrude oil distillation is performed to obtain the naphtha cut at 204 C (400 F). The distillation method was adap
9、ted fromTest Method D86 for the distillation of petroleum products. The naphtha cut is washed with caustic, repeatedly when necessary,until all hydrogen sulfide is removed. The naphtha cut, free of hydrogen sulfide, is then washed with water, repeatedly whennecessary, to remove inorganic halides (ch
10、lorides).3.2 There are two alternative test methods for determination of the organic chloride in the washed naphtha fraction, as follows.3.2.1 Test Method A, Sodium Biphenyl Reduction and PotentiometryThe washed naphtha fraction of a crude oil specimen isweighed and transferred to a separatory funne
11、l containing sodium biphenyl reagent in toluene. The reagent is an additioncompound of sodium and biphenyl in ethylene glycol dimethyl ether. The free radical nature of this reagent promotes very rapidconversion of the organic halogen to inorganic halide. In effect this reagent solubilizes metallic
12、sodium in organic compounds. The1 These test methods are under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and are the direct responsibility ofSubcommittee D02.03 on Elemental Analysis.Current edition approved June 1, 2015Dec. 1, 2015. Published June 20
13、15December 2015. Originally approved in 1989. Last previous edition approved in 20142015 asD4929 07 (2014).D4929 15. DOI: 10.1520/D4929-15.10.1520/D4929-15A.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of AST
14、M Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically po
15、ssible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardC
16、opyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1excess reagent is decomposed, the mixture acidified, and the phases separated. The aqueous phase is evaporated to 25 mL to30 mL, acetone is added, and the solution titrated potentiometric
17、ally.3.2.2 Test Method B, Combustion and Microcoulometry The washed naphtha fraction of a crude oil specimen is injected intoa flowing stream of gas containing about 80 % oxygen and 20 % inert gas, such as argon, helium, or nitrogen. The gas and sampleflow through a combustion tube maintained at abo
18、ut 800 C. The chlorine is converted to chloride and oxychlorides, which thenflow into a titration cell where they react with the silver ions in the titration cell. The silver ions thus consumed are coulometricallyreplaced. The total current required to replace the silver ions is a measure of the chl
19、orine present in the injected samples.3.2.3 The reaction occurring in the titration cell as chloride enters is as follows:Cl21Ag1AgCls! (1)3.2.4 The silver ion consumed in the above reaction is generated coulometrically thus:AgAg11e2 (2)3.2.5 These microequivalents of silver are equal to the number
20、of microequivalents of titratable sample ion entering the titrationcell.4. Significance and Use4.1 Usually organic Organic chlorides do not occur naturally in crude oil. When present, they result from contamination in somemanner, such as disposal of waste solvent or as use for dewaxing a chlorinated
21、 solvent used in many dewaxing pipeline or otherequipment.equipment operations.4.1.1 While an uncontaminated Uncontaminated crude oil will contain zero ppm of organic chloride, a very small amount iscapable of being handled in a refinery.no detectable organic chloride, and most refineries can handle
22、 very small amounts withoutdeleterious effects.4.1.1.1 Most trade contracts specify that no organic chloride is present in the crude oil.4.1.2 A rule of thumb used by refiners isSeveral pipelines have set specification limits at 1 mg 1 ppm kg organic chloridesin the whole crude, and 55 mg ppm kg in
23、the light naphtha, when the naphtha fraction is 20 % on the basis of the naphtha fractionbeing 20 % of the original sample.4.1.2.1 For refiners to ensure To ensure 1 mg 1 ppm kg organic chloride in the crude oil, the amount measured in the naphthafraction mustshall be 1/f 1/f (where f is the naphtha
24、 fraction calculated with Eq 3).4.1.3 Any organic halide Organic chloride present in the crude oil almost always distills (for example, methylene chloride,perchloroethylene, etc.) is usually distilled into the naphtha fraction. Some varieties can compounds break down duringfractionation but most sur
25、vive this process and produce hydrochloric acid, which has a corrosive effect. Some compounds survivefractionation and are destroyed during further refining usually during hydro-treating (desulfurization of the naphtha).4.2 Sometimes other halides have been Other halides can also be used for dewaxin
26、g crude oil; in such cases, any organic halideswill cause the same problemshave similar impact on the refining operations as the organic chlorides.4.3 Organic chloride species are potentially damaging to refinery processes. Hydrochloric acid can be produced in hydrotreatingor reforming reactors and
27、the acid accumulates in condensing regions of the refinery. Unexpected concentrations of organicchlorides cannot be effectively neutralized and damage can result. Organic chlorides are not known to be naturally present in crudeoils and usually result from cleaning operations at producing sites, pipe
28、lines, or tanks. It is important for the oil industry to havecommon methods available for the determination of organic chlorides in crude oil, particularly when transfer of custody isinvolved.5. Interferences5.1 Test Method AOther titratable halides will also give a positive response. These titratab
29、le halides include HBr and HI.5.2 Test Method BOther titratable halides will also give a positive response. These titratable halides include HBr and HI(HOBr and HOI do not precipitate silver). Since these oxyhalides do not react in the titration cell, approximately 50 %microequivalent response is de
30、tected.5.2.1 This test method is applicable in the presence of total sulfur concentration of up to 10 000 times the chlorine level.6. Purity of Reagents6.1 Purity of ReagentsReagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that allreagents shall conform
31、to the specifications of the Committee on Analytical Reagents of the American Chemical Society, wheresuch specifications are available.3 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently highpurity to permit its use without lessening the accuracy of the d
32、etermination.3 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For Suggestions on the testing of reagents not listed bythe American Chemical Society, see Annual Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United S
33、tates Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.D4929 15a26.2 Purity of WaterUnless otherwise indicated, references to water shall be understood to mean reagent water as defined byType III of Specification D1193.DISTILLATION AND CLEANUP PROCEDURE7.
34、 Apparatus7.1 Round-Bottom Boiling Flask, borosilicate, 1 L, single short neck with 24/40 outer ground-glass joint.7.2 Tee Adapter, borosilicate, 75 angle side-arm, 24/40 ground-glass joints.7.3 Thermometer, ASTM thermometer 2C (5 C to 300 C) or 2F, (20 F to 580 F).7.3.1 Other temperature measuring
35、devices, such as thermocouples or resistance thermometers, may be used when thetemperature reading obtained by these devices is determined to produce the same naphtha fraction that is obtained whenmercury-in-glass thermometers are used.7.4 Thermometer Adapter, borosilicate, 24/40 inner ground-glass
36、joint.7.5 Liebig Condenser, borosilicate, 300 mm length, 24/40 ground-glass joints.7.6 Vacuum Take-Off Adapter, borosilicate, 105 angle bend, 24/40 ground-glass joints.7.7 Receiving Cylinder, borosilicate, 250 mL capacity, 24/40 outer ground-glass joint.7.8 Wire Clamps, for No. 24 ground-glass joint
37、s, stainless steel.7.9 Receiver Flask, for ice bath, 4 L.7.10 Copper Tubing, for heat exchanger to cool condenser water, 6.4 mm outside diameter, 3 m length.7.11 Electric Heating Mantle, Glas-Col Series 0, 1 L size, 140 W upper heating element, 380 W lower heating element.7.12 Variacs, 2, for temper
38、ature control of upper and lower heating elements, 120 V, 10 amps.8. Reagents and Materials8.1 Acetone, chloride-free. (WarningExtremely flammable, can cause flash fires. Health hazard.)8.2 Caustic Solution, 1 M potassium hydroxide (WarningCan cause severe burns to skin.) prepared in distilled/deion
39、izedwater.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. Health hazard.)9. Sampling9.1 Obtain a test unit in accordance with Practice D4057 or D4177. To preserve volatile components, which are in some
40、samples, do not uncover samples any longer than necessary. Samples should be analyzed as soon as possible, after taking frombulk supplies, to prevent loss of organic chloride or contamination due to exposure or contact with sample container.(WarningSamples that are collected at temperatures below ro
41、om temperature may undergo expansion and rupture the container.For such samples, do not fill the container to the top; leave sufficient air space above the sample to allow room for expansion.)9.2 If the test unit is not used immediately, then thoroughly mix in its container prior to taking a test sp
42、ecimen. Some test unitscan require heating to thoroughly homogenize. (WarningWhen heating is required, care should be taken so that no organicchloride containing hydrocarbons are lost.)10. Preparation of Apparatus10.1 Clean all glassware by rinsing successively with toluene and acetone. After comple
43、ting the rinse, dry the glassware usinga stream of dry nitrogen gas. Obtain and record the masses of the round-bottom flask and receiving cylinder. Assemble the glassdistillation apparatus using stopcock grease to seal all joints and wire clamps to prevent loosening of the joints. Adjust thethermome
44、ter position within the adapter tee such that the lower end of the capillary is level with the highest point on the bottomof the inner wall of the adapter tee section that connects to the condenser.4 The sole source of supply of the stop-cock grease known to the committee at this time is Dow Corning
45、 silicone, available from Dow Corning Corporation, CorporateCenter, PO Box 994, Midland, MI.5 If you are aware of alternative suppliers, please provide this information to ASTM International Headquarters. Your comments will receive careful consideration at ameeting of the responsible technical commi
46、ttee, 1 which you may attend.D4929 15a3NOTE 1A diagram illustrating the appropriate positioning of the thermometer can be found in Test Method D86.10.2 Form the copper tubing into a coil to fit inside the receiver flask, leaving room in the center of the flask for the receivingcylinder. With the PVC
47、 tubing, connect one end of the copper coil to the water source, and connect the other end of the coil tothe lower fitting of the Liebig condenser cooling jacket. Connect the upper condenser fitting to the water drain. Fill the receiverflask with an ice/water mixture, and turn on the water. Maintain
48、 the temperature of the condenser below 10 C.11. Procedure11.1 Add a 500 mL crude oil test specimen to tared round bottom flask. Obtain and record the mass of the crude oil-filled flaskto the nearest 0.1 g. Connect the flask to the distillation apparatus. Place the heating mantle around the flask, a
49、nd support theheating mantle/flask from the bottom. Connect the heating mantle to the variacs. Turn on the variacs and start the distillation.During the distillation, adjust the variac settings to give a distillation rate of approximately 5 mLmin. Continue the distillationuntil a thermometer reading of 204 C (400 F) is attained. When the temperature reaches 204 C (400 F), end the distillation byfirst disconnecting and removing the receiving cylinder. After the receiving cylinder has been removed, turn off the variacs andremove the heating ma
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