1、Designation: D4929 16D4929 17Standard Test Method 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 last
2、 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 The procedures in this test method cover the determination of organic chloride (above 1 g/g organically-bound chlorine)in
3、 crude oils, using either distillation and sodium biphenyl reduction reduction, distillation and microcoulometry, or distillation andmicrocoulometry. x-ray fluorescence (XRF) spectrometry.1.2 The procedures in this test method involve the distillation of crude oil test specimens to obtain a naphtha
4、fraction prior tochloride determination. The chloride content of the naphtha fraction of the whole crude oil can thereby be obtained. See Section5 regarding potential interferences.1.3 Procedure A covers the determination of organic chloride in the washed naphtha fraction of crude oil by sodium biph
5、enylreduction followed by potentiometric titration.1.4 Procedure B covers the determination of organic chloride in the washed naphtha fraction of crude oil by oxidativecombustion followed by microcoulometric titration.1.5 Procedure C covers the determination of organic chloride in the washed naphtha
6、 fraction of crude oil by x-ray fluorescencespectrometry.1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.6.1 The preferred concentration units are micrograms of chloride per gram of sample.1.7 This standard does not purp
7、ort 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 safety, health, and healthenvironmental practices and determine theapplicability of regulatory limitations prior to use.1.8 This internatio
8、nal standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee
9、.2. Referenced 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
10、 Petroleum ProductsD6299 Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measure-ment System PerformanceD6300 Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and LubricantsD6708 Practice f
11、or Statistical Assessment and Improvement of Expected Agreement Between Two Test Methods that Purportto Measure the Same Property of a MaterialD7343 Practice for Optimization, Sample Handling, Calibration, and Validation of X-ray Fluorescence Spectrometry Methodsfor Elemental Analysis of Petroleum P
12、roducts and Lubricants1 This test method is under the jurisdiction ofASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of SubcommitteeD02.03 on Elemental Analysis.Current edition approved Oct. 1, 2016Oct. 15, 2017. Published October 2016December
13、2017. Originally approved in 1989. Last previous edition approved in 20152016as D4929 15a.16. DOI: 10.1520/D4929-16.10.1520/D4929-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume inform
14、ation, 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 possible to adequately dep
15、ict 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 standardCopyright ASTM Internatio
16、nal, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13. Summary of Test Method3.1 Acrude oil distillation is performed to obtain the naphtha cut at 204 C (400 F). The distillation method was adapted fromTest Method D86 for the distillation of petroleum products. T
17、he 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 (chlorides).3.2 There are twothree alternative procedures for determinat
18、ion of the organic chloride in the washed naphtha fraction, asfollows.3.2.1 Procedure A, Sodium Biphenyl Reduction and PotentiometryThe washed naphtha fraction of a crude oil specimen isweighed and transferred to a separatory funnel containing sodium biphenyl reagent in toluene. The reagent is an ad
19、ditioncompound 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 sodium in organic compounds. Theexcess reagent is decomposed, the mix
20、ture acidified, and the phases separated. The aqueous phase is evaporated to 25 mL to30 mL, acetone is added, and the solution titrated potentiometrically.3.2.2 Procedure B, Combustion and Microcoulometry The washed naphtha fraction of a crude oil specimen is injected intoa flowing stream of gas con
21、taining about 80 % oxygen and 20 % inert gas, such as argon, helium, or nitrogen. The gas and sampleflow through a combustion tube maintained at about 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 titr
22、ation cell. The silver ions thus consumed are coulometricallyreplaced. The total current required to replace the silver ions is a measure of the chlorine present in the injected samples.3.2.3 The reaction occurring in the titration cell as chloride enters is as follows:Cl21Ag1AgCl s! (1)3.2.4 The si
23、lver ion consumed in the above reaction is generated coulometrically thus:AgAg11e2 (2)3.2.5 These microequivalents of silver are equal to the number of microequivalents of titratable sample ion entering the titrationcell.3.2.6 Procedure C, X-ray Fluorescence SpectrometryThe washed naphtha fraction o
24、f a crude oil specimen is placed in theX-ray beam, and the peak intensity of the chlorine K line is measured by monochromatic wavelength dispersive x-rayfluorescence (MWDXRF), monochromatic energy dispersive x-ray fluorescence (MEDXRF), or energy dispersive x-rayfluorescence (EDXRF) spectrometry. Th
25、e resulting net counting rate is then compared to a previously prepared calibration curveor equation to obtain the concentration of chlorine in mg/kg.4. Significance and Use4.1 Organic chlorides do not occur naturally in crude oil. When present, they result from contamination in some manner, suchas
26、disposal of chlorinated solvent used in many dewaxing pipeline or other equipment operations.4.1.1 Uncontaminated crude oil will contain no detectable organic chloride, and most refineries can handle very small amountswithout deleterious effects.4.1.1.1 Most trade contracts specify that no organic c
27、hloride is present in the crude oil.4.1.2 Several pipelines have set specification limits at 20W capable of producingPd L,Ag L, Ti K, Sc K, and Cr K radiation are recommended for this purpose. (WarningExposure to excessive quantitiesof high energy radiation such as those produced by X-ray spectromet
28、ers is injurious to health. The operator needs to takeappropriate actions to avoid exposing any part of their body, not only to primary X-rays, but also to secondary or scattered radiationthat might be present. The X-ray spectrometer should be operated in accordance with the regulations governing th
29、e use of ionizingradiation.)23.2.2 Optical Path, designed to minimize the absorption along the path of the excitation and fluorescent beams using a vacuumor a helium atmosphere. If vacuum is used, a level of lower than 2.7 kPa (20 Torr) is recommended. If helium is used, it isrecommended to limit va
30、riations in pressure and temperature to within 10 % relative. The calibration and test measurements mustbe done with identical optical paths, including vacuum or helium pressure.23.2.3 Incident-beam Monochromator, capable of focusing and selecting a single wavelength of characteristic x-rays from th
31、esource onto the specimen.23.2.4 Fixed-channel Monochromator, suitable for dispersing chlorine K x-rays.23.2.5 Detector, designed for efficient detection of chlorine K x-rays.23.2.6 Single-channel Analyzer, an energy discriminator to monitor only chlorine radiation.23.2.7 Display or Printer, that re
32、ads out in mg/kg chlorine.23.3 Monochromatic Energy Dispersive X-ray Fluorescence (MEDXRF) Spectrometer, including the following:23.3.1 Source of X-ray Excitation, x-ray tube with Ag or Pd anode, in combination with HOPG Bragg monochromating X-rayoptics. The monochromator must produce monochromatic
33、Ag or Pd L radiation. Other anode materials and monochromators maybe utilized, however stated precision and bias may not apply. (WarningExposure to excessive quantities of high energy radiationsuch as those produced by X-ray spectrometers is injurious to health. The operator needs to take appropriat
34、e actions to avoidexposing any part of their body, not only to primary X-rays, but also to secondary or scattered radiation that might be present. TheX-ray spectrometer should be operated in accordance with the regulations governing the use of ionizing radiation.)23.3.2 Optical Path, the system must
35、 allow flushing of the optical path with helium (see 24.6). When connecting a new heliumgas cylinder, always run a blank measurement to ensure the helium gas line is purged of air. Alternatively, a vacuum of 4.0 kPa(30.4 Torr) is applied to the optical path. If helium is used, it is recommended to l
36、imit variations in pressure and temperature towithin 10 % relative. When the air in the optical path is relatively small, then vacuum or helium may be optional. Followmanufacturers recommendations.23.3.3 X-ray Detector, with a resolution value not to exceed 175 eV at 5.9 keV (10 000 cps).ASi drift c
37、hamber detector (SDD)has been found suitable for use. Using a detection system with this minimum spectral resolution has been shown to eliminate thepotential effect of spectral interference from sulfur or other elements in the naphtha sample.23.3.4 Signal Conditioning and Data Handling Electronics,
38、including the functions of x-ray intensity counting, spectra handlingby background subtraction and deconvolution, calculation of overlap corrections and conversion of chlorine X-ray intensity intomg/kg chlorine concentration.D4929 171023.3.5 Display or Printer, that reads out in mg/kg chlorine.23.4
39、Energy Dispersive X-ray Fluorescence (EDXRF) Spectrometer, required design features include:23.4.1 Source of X-ray Excitation, Xray tube with excitation energy above 2.9 keV. (WarningExposure to excessivequantities of high energy radiation such as those produced by x-ray spectrometers is injurious t
40、o health. The operator needs to takeappropriate actions to avoid exposing any part of their body, not only to primary X-rays, but also to secondary or scattered radiationthat might be present. The X-ray spectrometer should be operated in accordance with the regulations governing the use of ionizingr
41、adiation.)23.4.2 X-ray Detector, with high sensitivity and a resolution value (Full Width at Half Maximum, FWHM) not to exceed 175eV at 5.9 keV (10 000 cps). A Si drift chamber detector (SDD) has been found suitable for use.23.4.3 Filters, or other means of discriminating between chlorine K radiatio
42、n and other x-rays of different energy. The othermeans include software solutions.23.4.4 Optical Path, the system must allow flushing of the optical path with helium (see 24.6). When connecting a new heliumgas cylinder, always run a blank measurement to ensure the helium gas line is purged of air. A
43、lternatively, a vacuum of 4.0 kPa(30.4 Torr) is applied to the optical path. If helium is used, it is recommended to limit variations in pressure and temperature towithin 10 % relative.23.4.5 Signal Conditioning and Data Handling Electronics, that include the functions of x-ray intensity counting, a
44、 minimumof two energy regions, spectral overlap corrections, background corrections, and conversion of chlorine x-ray intensity into masspercent chlorine concentration.23.4.6 Display or Printer, that reads out in mg/kg chlorine.23.5 Additionally, the following apparatus is needed when using all xray
45、 spectrometers within the scope of this method:23.5.1 Removable Sample Cell, an openended specimen holder compatible with the sample and the geometry of the XRFspectrometer. A disposable cell is recommended. The sample cell should not leak when fitted with x-ray transparent film (see23.5.2).23.5.2 X
46、-ray Transparent Film, for containing and supporting the test specimen in the sample cell (see 23.5.1) while providinga lowabsorption window for X-rays to pass to and from the sample. Any film resistant to chemical attack by the sample, free ofchlorine, and X-ray transparent can be used, for example
47、, polyester, polypropylene, polycarbonate, and polyimide. However,samples of high aromatic content can dissolve polyester and polycarbonate films.23.5.3 Analytical Balance, for preparing calibration standards, capable of weighing to the nearest 0.1 mg and up to 100 g.24. Reagents and Materials24.1 P
48、urity of ReagentsReagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that allreagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where suchspecifications are available.7 Other grades may be used, p
49、rovided it is first ascertained that the reagent is of sufficiently high purityto permit its use without lessening the accuracy of the determination.24.2 Calibration Check Samples, portions of one or more liquid petroleum or product standards of known or certified chlorinecontent and not used in the generation of the calibration curve. The check samples shall be used to determine the precision andaccuracy of the initial calibration (see 27.6).24.3 Chlorine Dopant (CD), a highpurity standard with a certified chlorine content. Trichloroethylene and
