1、Manual of PetroleumMeasurement StandardsChapter 10Sediment and WaterSection 7Standard Test Method for Water in Crude Oils by Potentiometric Karl Fischer TitrationSECOND EDITION, DECEMBER 2002REAFFIRMED, MAY 2011Manual of PetroleumMeasurement StandardsChapter 10Sediment and WaterSection 7Standard Tes
2、t Method for Water in Crude Oils by Potentiometric Karl Fischer TitrationMeasurement CoordinationSECOND EDITION, DECEMBER 2002REAFFIRMED, MAY 2011SPECIAL NOTESAPI publications necessarily address problems of a general nature. With respect to partic-ular circumstances, local, state, and federal laws
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16、iCONTENTSPage1 SCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 REFERENCED DOCUMENTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 SUMMARY OF TEST METHOD . . . . . . . . .
17、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 SIGNIFICANCE AND USE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 INTERFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
18、. 16 APPARATUS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 REAGENTS AND MATERIALS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 SAMPLING AND TEST SAMPLES. . . . . . . . . . . . . . . . . .
19、 . . . . . . . . . . . . . . . . . . . . . 29 CALIBRATION AND STANDARDIZATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 310 PROCEDURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 311 CALCULATIONS. . . . . . . . .
20、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 312 PRECISION AND BIAS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4ANNEX A1 HOMOGENIZATION EFFICIENCY OF UNKNOWN MIXERS . . . . . 4ANNEX A2 APPARATUS . . .
21、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5FiguresA2.1 Apparatus for Determination of Water by Karl Fischer Reagent. . . . . . . . . . . . . . 5A2.2 Electrode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
22、 . . . . . . . . . 6Tables1 Test Sample% Water Content Based on Sample Size . . . . . . . . . . . . . . . . . . . . 32 Precision Intervals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4vDesignation: D 4377 00e1Designation: Manual of Petroleum Me
23、asurement Standards (MPMS), Chapter 10.7Designation: 356/99An American National StandardStandard Test Method forWater in Crude Oils by Potentiometric Karl Fischer Titration1This standard is issued under the fixed designation D 4377; the number immediately following the designation indicates the year
24、 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 (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Departme
25、nt of Defense.e1NOTEFootnote 1 and the Referenced Documents were corrected editorially to comply with the ASTM-API joint standardcontract in October 2002.1. Scope1.1 This test method covers the determination of water inthe range from 0.02 to 2 % in crude oils. Mercaptan and sulfide(Sor H2S) sulfur a
26、re known to interfere with this test method(see Section 5).1.2 This test method is intended for use with standard KarlFischer reagent or pyridine-free Karl Fischer reagents.1.3 The values stated in SI units are to be regarded as thestandard.1.4 This standard does not purport to address all of thesaf
27、ety 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. Specific precau-tionary statements are given in Section 7.2. Referenced D
28、ocuments2.1 ASTM Standards:D 1193 Specification for Reagent Water2D 4006 Test Method for Water in Crude Oil by Distillation(API MPMS Chapter 10.2)3D 4057 Practice for Manual Sampling of Petroleum andPetroleum Products (API MPMS Chapter 8.1)3D 4177 Practice for Automatic Sampling of Petroleum andPetr
29、oleum Products (API MPMS Chapter 8.2)3E 203 Test Method for Water Using Volumetric Karl FischerReagent42.2 API Standards:5MPMS Chapter 8.1 Manual Sampling of Petroleum andPetroleum Products (ASTM Practice D 4057)MPMS Chapter 8.2 Automatic Sampling of Petroleum andPetroleum Products (ASTM Practice D
30、4177)MPMS Chapter 10.2 Determination of Water in Crude Oilby Distillation (ASTM Test Method D 4006)3. Summary of Test Method3.1 After homogenizing the crude oil with a mixer, analiquot of the crude, in a mixed solvent, is titrated to anelectrometric end-point using Karl Fischer reagent.4. Significan
31、ce and Use4.1 A knowledge of the water content of crude oil isimportant in the refining, purchase, sale, or transfer of crudeoils.5. Interferences5.1 A number of substances and class of compounds asso-ciated with condensation or oxidation-reduction reactions in-terfere in the determination of water
32、by Karl Fischer. In crudeoils, the most common interferences are mercaptans andsulfides. At levels of less than 500 g/g (ppm) (as sulfur) theinterference from these compounds is insignificant. For moreinformation on substances that interfere in the determination ofwater using the (Karl Fischer reage
33、nt) titration method see TestMethod E 203.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and the API Committee on Petroleum Measure-ment, and is the direct responsibility of Subcommittee D02.02/COMQ, the jointASTM-API Committee on Static Petrole
34、um Measurement.Current edition approved Aug. 10, 2000. Published October 2000. Originallypublished as D 437784. Last previous edition D 437793a.2Annual Book of ASTM Standards, Vol 11.01.3Annual Book of ASTM Standards, Vol 05.02.4Annual Book of ASTM Standards, Vol 15.05.5Published as Manual of Petrol
35、eum Measurement Standards. Available from theAmerican Petroleum Institute (API), 1220 L St., NW, Washington, DC 20005-4070.1 6. Apparatus6.1 Karl Fischer Apparatus, using electrometric end-point.A suggested assembly of the apparatus is described in AnnexA2.6.1.1 Presently there is available on the m
36、arket commercialKarl Fischer titration assemblies, some of which automaticallystop the titration at the end-point. Instructions for operation ofthese devices are provided by the manufacturer and notdescribed herein. This test method is not intended for use withcoulometric Karl Fischer titrators.6.2
37、Mixer, to homogenize the crude sample.6.2.1 Non-Aerating, High-Speed, Shear Mixer,6capable ofmeeting the homogenization efficiency test described in AnnexA1. The sample size is limited to that suggested by themanufacturer for the size of the probe.6.3 Syringes:6.3.1 Samples and base liquid are most
38、easily added to thetitration vessel by means of accurate glass syringes with LUERfittings and hypodermic needles of suitable length. The boresof the needles used should be kept as small as possible, butlarge enough to avoid problems arising from back pressure/blocking whilst sampling. Suggested syri
39、nge sizes are asfollows:6.3.1.1 Syringe, 10 L, with a needle long enough to dipbelow the surface of the base solution in the cell during thestandardization procedure (see Section 9).6.3.1.2 Syringes, 2.5 mL, 5 mL, and 10 mL for crude oilsamples (see Section 10).6.3.1.3 Syringe, 20 mL or larger for s
40、ample solvent.7. Reagents and Materials7.1 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 American Chemical Society,where such specifi
41、cations are available.7Other 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.7.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent w
42、ater as definedby Type IV of Specification D 1193.7.3 1-Ethylpiperidine (99 + percent). (WarningIrritant.Flammable.)7.4 Karl Fischer Reagents, Standard reagent containingpyridine (7.4.1) or pyridine-free reagent (7.4.2).7.4.1 Karl Fischer Reagent Ethylene Glycol MonomethylEther Solution, stabilized,
43、 containing pyridine, (1 mL = 5 mgof water)Fresh Karl Fischer reagent must be used. Must beused with solvent in 7.6.1. (WarningCombustible. Harmfulif swallowed, inhaled, or absorbed through the skin.)7.4.2 Pyridine-Free Karl Fischer (one-component) reagentdiluted with xyleneDilute three parts pyridi
44、ne-free KarlFischer (one-component) reagent8(1 mL = 5 mg water) to 1part xylene. Fresh Karl Fischer reagent must be used.(WarningSee 7.4.1) Must be used with solvent in 7.6.2.7.5 Methanol (anhydrous), Maximum 0.1 % water but pref-erably less than 0.05 % water. (WarningFlammable. Vaporharmful. May be
45、 fatal or cause blindness if swallowed orinhaled. Cannot be made nonpoisonous.)7.6 Sample SolventUse 7.6.1 for standard Karl Fischerreagent containing pyridine and 7.6.2 for pyridine-free KarlFischer reagent.7.6.1 Sample SolventMix 40 mL of 1-ethylpiperidine, 20mL of methanol, and 40 mL of Karl Fisc
46、her reagent in asealable glass bottle. Allow this mixture to sit overnight beforeadding 200 mL of xylene. Additional methanol may berequired in some cases for the proper function of the elec-trodes. (Warningsee 7.3.)7.6.2 Sample Solvent for Pyridine-Free ReagentsMix 3parts chloroform to 1 part pyrid
47、ine-free solvent using solventpart of two-component reagent8(contains SO2and odorlessamine dissolved in methanol) and store in a sealable glassbottle. An evaluation of a number of crude oils has demon-strated that xylene can be substituted for chloroform with noapparent change in accuracy of this te
48、st method. (WarningFlammable. Vapor harmful.) (Also, see 7.4.1.)7.7 Xylene, reagent grade. Less than 0.05 % water.7.8 Chloroform, reagent grade. (WarningHarmful if in-haled or swallowed. Carcinogen (animal positive). Skin andeye irritant. May produce toxic vapors if burned.8. Sampling and Test Sampl
49、es8.1 Sampling, is defined as all the steps required to obtain analiquot representative of the contents of any pipe, tank, or othersystem, and to place the sample into the laboratory testcontainer. The laboratory test container and sample volumeshall be of sufficient dimensions and volume to allow mixing asdescribed in 8.1.2.1.8.1.1 Laboratory SampleOnly representative samples ob-tained as specified in Practice D 4057 (API MPMS Chapter8.1) and Practice D 4177 (API MPMS Chapter 8.2) sh
