1、Designation: D4007 11Designation: Manual of Petroleum Measurement Standards (MPMS), Chapter 10.3Standard Test Method forWater and Sediment in Crude Oil by the Centrifuge Method(Laboratory Procedure)1This standard is issued under the fixed designation D4007; the number immediately following the desig
2、nation indicates the year 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 () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method describes the
3、 laboratory determinationof water and sediment in crude oils by means of the centrifugeprocedure. This centrifuge method for determining water andsediment in crude oils is not entirely satisfactory. The amountof water detected is almost always lower than the actual watercontent. When a highly accura
4、te value is required, the revisedprocedures for water by distillation, Test Method D4006 (APIMPMS Chapter 10.2) (Note 1), and sediment by extraction,Test Method D473 (API MPMS Chapter 10.1), shall be used.NOTE 1Test Method D4006 (API MPMS Chapter 10.2) has beendetermined to be the preferred and most
5、 accurate method for thedetermination of water.1.2 The values stated in SI units are to be regarded asstandard. The values given in parentheses are for informationonly.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of
6、 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 warningstatements appear in 6.1, 8.3, and A1.5.4.2. Referenced Documents2.1 ASTM Standards:2D95 Test Method for Water in Petroleum Produc
7、ts andBituminous Materials by DistillationD473 Test Method for Sediment in Crude Oils and Fuel Oilsby the Extraction MethodD665 Test Method for Rust-Preventing Characteristics ofInhibited Mineral Oil in the Presence of WaterD1796 Test Method for Water and Sediment in Fuel Oils bythe Centrifuge Metho
8、d (Laboratory Procedure)D4006 Test Method for Water in Crude Oil by DistillationD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsD4928 Test Method forWater in Crude Oils by CoulometricKarl Fischer TitrationD5
9、854 Practice for Mixing and Handling of Liquid Samplesof Petroleum and Petroleum ProductsE969 Specification for Glass Volumetric (Transfer) Pipets2.2 API Standards:3MPMS Chapter 8.1 Manual Sampling of Petroleum andPetroleum Products (ASTM Practice D4057)MPMS Chapter 8.2 Automatic Sampling of Petrole
10、um andPetroleum Products (ASTM Practice D4177)MPMS Chapter 8.3 Mixing and Handling of Liquid Samplesof Petroleum and Petroleum Products (ASTM PracticeD5854)MPMS Chapter 10.1 Determination of Sediment in CrudeOils and Fuel Oils by the Extraction Method (ASTM TestMethod D473)MPMS Chapter 10.2 Determin
11、ation of Water in Crude Oilby Distillation (ASTM Test Method D4006)MPMS Chapter 10.4 Determination of Sediment and Waterin Crude Oil by the Centrifuge Method (Field Procedure)MPMS Chapter 10.5 Determination of Water in PetroleumProducts and Bituminous Materials by Distillation(ASTM Test Method D95)M
12、PMS Chapter 10.6 Determination of Water and Sedimentin Fuel Oils by the Centrifuge Method (Laboratory Pro-cedures) (ASTM Test Method D1796)MPMS Chapter 10.9 Test Method for Water in Crude Oilsby Coulometric Karl Fischer Titration (ASTM TestMethod D4928)1This test method is under the jurisdiction of
13、ASTM Committee D02 onPetroleum Products and Lubricants and the API Committee on Petroleum Measure-ment and is the direct responsibility of Subcommittee D02.02.10 on Sediment andWater (API MPMS Chapter 10.0).This test method was issued as a joint ASTM-API-IP standard in 1981.Current edition approved
14、June 1, 2011. Published August 2011. Originallyapproved in 1981. Last previous edition approved in 2008 as D400708. DOI:10.1520/D4007-11.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume i
15、nformation, refer to the standards Document Summary page onthe ASTM website.3Available from American Petroleum Institute (API), 1220 L. St., NW, Wash-ington, DC 20005-4070, www.api.org.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Dr
16、ive, PO Box C700, West Conshohocken, PA 19428-2959, United States.2.3 IP Standard:4Methods Book, Appendix B Specification for Methylben-zenes (Toluenes)2.4 ISO Standard:5ISO 5272:1979 Toluene for Industrial UseSpecifications3. Summary of Test Method3.1 Equal volumes of crude oil and water-saturated
17、tolueneare placed into a cone-shaped centrifuge tube. After centrifu-gation, the volume of the higher density water and sedimentlayer at the bottom of the tube is read.4. Significance and Use4.1 The water and sediment content of crude oil is signifi-cant because it can cause corrosion of equipment a
18、nd problemsin processing.Adetermination of water and sediment content isrequired to measure accurately net volumes of actual oil insales, taxation, exchanges, and custody transfers. It is notanticipated that this test method, which is written with adedicated laboratory facility in mind, is likely to
19、 be used infield test rooms or sample rooms due to safety concerns forproper ventilation and handling.4.2 This test method may not be suitable for crude oils thatcontain alcohols that are soluble in water. In cases where theimpact on the results may be significant, the user is advised toconsider usi
20、ng another test method, such as Test MethodD4928 (API MPMS Chapter 10.9).5. Apparatus5.1 Centrifuge:5.1.1 A centrifuge capable of spinning two or more filledcone-shaped, 203-mm (8-in.) centrifuge tubes at a speed thatcan be controlled to give a relative centrifugal force (rcf) of aminimum of 600 at
21、the tip of the tubes shall be used (see 5.1.6).5.1.2 The revolving head, trunnion rings, and trunnion cups,including the cushions, shall be soundly constructed to with-stand the maximum centrifugal force capable of being deliv-ered by the power source. The trunnion cups and cushions shallfirmly supp
22、ort the tubes when the centrifuge is in motion. Thecentrifuge shall be enclosed by a metal shield or case strongenough to eliminate danger if any breakage occurs.5.1.3 The centrifuge shall be heated and controlled thermo-statically to avoid unsafe conditions. It shall be capable ofmaintaining the sa
23、mple temperature during the entire run at 606 3C (140 6 5F). The thermostatic control shall be capableof maintaining the temperature within these limits and operatesafely if there is a flammable atmosphere.5.1.4 Electric powered and heated centrifuges must meet allsafety requirements for use in haza
24、rdous areas.5.1.5 Calculate the necessary minimum speed of the rotat-ing head in revolutions per minute (r/min) as follows:r/min 5 1335 =rcf/d (1)where:rcf = relative centrifugal force andd = diameter of swing measured between tips of oppositetubes when in rotating position, mm, orr/min 5 265 =rcf/d
25、 (2)where:rcf = relative centrifugal force andd = diameter of swing measured between tips of oppositetubes when in rotating position, in.5.1.6 Calculate the relative centrifugal force from a mea-sured speed (r/min) as follows:rcf 5 dSr/min1335D2(3)where:d = diameter of swing measured between tips of
26、 oppositetubes when in rotating position, mm, orrcf 5 dSr/min265D2(4)where:d = diameter of swing measured between tips of oppositetubes when in rotating position, in.5.2 Centrifuge TubesEach centrifuge tube shall be a203-mm (8-in.) cone-shaped tube, conforming to dimensionsgiven in Fig. 1 and made o
27、f thoroughly annealed glass. Thegraduations, numbered as shown in Fig. 1, shall be clear and4Available from Energy Institute, 61 New Cavendish St., London, WIG 7AR,U.K., http:/www.energyinst.org.uk.5Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 1
28、0036, http:/www.ansi.org.FIG. 1 Eight-Inch (203-mm) Centrifuge TubeD4007 112distinct, and the mouth shall be constricted in shape for closurewith a cork. Scale error tolerances and the smallest graduationsbetween various calibration marks are given in Table 1 andapply to calibrations made with air-f
29、ree water at 20C (68F),when reading the bottom of the shaded meniscus. The accuracyof the graduations on the centrifuge tube shall be volumetri-cally verified, before use of the tube. The verification shallinclude calibration at each mark up to the 0.25 mL mark (asshown in Fig. 2), and at the 0.5, 1
30、.0, 1.5, 2.0, 50.0, and 100 mLmarks. The tube shall not be used if the scale error at any markexceeds the applicable tolerance from Table 1.5.3 BathThe bath shall be either a solid metal block bathor a liquid bath of sufficient depth for immersing the centrifugetube in the vertical position to the 1
31、00-mL mark. Means shallbe provided for maintaining the temperature at 60 6 3C (1406 5F). For some crude oils, temperatures of 71 6 3C (160 65F) may be required to melt wax crystals in crude oils. Forthese crude oils, the test temperature shall be maintained highenough to ensure the absence of wax cr
32、ystals.5.4 50 mL Pipet, Class A, or equivalent volume dispensingdevice, capable of delivering a volume of 50 6 0.05 mL (seeSpecification E969) for use in the test.6. Solvent6.1 TolueneReagent grade conforming to the specifica-tions of the Committee onAnalytical Reagents of theAmericanChemical Societ
33、y (ACS)6or to Grade 2 of ISO 5272 orconforming to the EI Specification for Methylbenzenes (Tolu-enes). (WarningFlammable. Keep away from heat, sparks,and open flame. Vapor harmful. Toluene is toxic. Particularcare must be taken to avoid breathing the vapor and to protectthe eyes. Keep container clos
34、ed. Use with adequate ventilation.Avoid prolonged or repeated contact with the skin.)6.1.1 Typical characteristics for this reagent are:Assay 99.5+ %Color (APHA) 10Boiling range (initial to dry point)(Recorded boiling point 110.6C)2.0CResidue after evaporation 0.001 % max wt/wtSubstances darkened by
35、 H2SO4passes testSulfur compounds (as S) 0.003 % max wt/wtWater (H2O) (by Karl Fischer titration) 0.03 % max wt/wt6.1.2 The solvent shall be water-saturated at 60 6 3C (1406 5F) (see 5.3) but shall be free of suspended water. SeeAnnex A1 for the solvent-water saturation procedure.6.2 DemulsifierA de
36、mulsifier should be used to promotethe separation of water from the sample and to prevent itsclinging to the walls of the centrifuge tube. The recommendedstock solution is 25 % demulsifier to 75 % toluene. For somecrude oils a different ratio of demulsifier to toluene may berequired. Demulsifiers us
37、ed in the concentration and quantityrecommended will not add to the water and sediment volumedetermined. The solution must be stored in a dark bottle that istightly closed.7. Sampling7.1 Sampling is defined as all steps required to obtain analiquot of the contents of any pipe, tank, or other system
38、and toplace the sample into the laboratory test container.7.2 Only representative samples obtained as specified inPractices D4057 (API MPMS Chapter 8.1) and Practice D4177(API MPMS Chapter 8.2) shall be used for this test method.7.3 Sample Mixingis typically required to obtain a testportion represen
39、tative of the bulk sample to be tested, butprecautions shall be taken to maintain the integrity of thesample during this operation. Mixing of volatile crude petro-leum containing water or sediments, or both, may result in theloss of light components.Additional information on the mixingand handling o
40、f liquid samples can be found in Practice D5854(API MPMS Chapter 8.3).8. Procedure8.1 Fill each of two centrifuge tubes (5.2) to the 50-mLmark with sample directly from the sample container. Using apipet or other suitable volume transfer device (see 5.4), add 506 0.05 mL of toluene, which has been w
41、ater saturated at 60C(140F) or 71C (160F) (see 5.3). Read the top of themeniscus at both the 50 and 100-mL marks. Add 0.2 mL ofdemulsifier solution (6.2) to each tube, using a 0.2-mL pipet orother suitable volume transfer device, such as an automaticpipettor. Stopper the tube tightly and invert the
42、tubes ten timesto ensure that the oil and solvent are uniformly mixed.8.2 In the case where the crude oil is very viscous andmixing of the solvent with the oil would be difficult, the solventmay be added to the centrifuge tube first to facilitate mixing.Take care to not fill the centrifuge tube past
43、 the 100-mL markwith the sample.8.3 Loosen the stoppers slightly and immerse the tubes tothe 100-mL mark for at least 15 min in the bath maintained at60 6 3C (140 6 5F) (see 5.3). Secure the stoppers and againinvert the tubes ten times to ensure uniform mixing of oil andsolvent. (WarningThe vapor pr
44、essure at 60C (140F) isapproximately double that at 40C (104F).)8.4 Place the tubes in the trunnion cups on opposite sides ofthe centrifuge to establish a balanced condition. (If the tubescannot be counter-balanced by eye, place them, in theirtrunnion cups, on either side of a balance and equalize t
45、heirmasses by the addition of water to the trunnion cups.) Re-tighten the corks and spin for 10 min at a minimum relativecentrifugal force of 600 calculated from the equation given in5.1.6.6Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For Sug
46、gestions on the testing 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.TABLE 1 Centrifuge Tube Cali
47、bration Tolerancesfor 203-mm (8-in.) TubeRange, mL Subdivision, mL Volume Tolerance, mL0to0.1 0.05 60.02Above 0.1 to 0.3 0.05 60.03Above 0.3 to 0.5 0.05 60.05Above 0.5 to 1.0 0.10 60.05Above 1.0 to 2.0 0.10 60.10Above 2.0 to 3.0 0.20 60.10Above 3.0 to 5.0 0.5 60.20Above 5.0 to 10 1.0 60.50Above 10 t
48、o 25 5.0 61.00Above 25 to 100 25.0 61.00D4007 113FIG. 2 Procedure for Reading Water and Sediment When Using an ASTM 100-mm Cone-Shaped Centrifuge TubeD4007 1148.5 Immediately after the centrifuge comes to rest followingthe spin, read and record the combined volume of water andsediment at the bottom
49、of each tube, to the nearest 0.05 mLfrom 0.1 to 1-mL graduations, and to the nearest 0.1-mL above1-mL graduations. Below 0.1 mL, estimate to the nearest0.025 mL(refer to Fig. 2). Return the tubes without agitation tothe centrifuge and spin for another 10 min at the same rate.8.6 Repeat this operation until the combined volume ofwater and sediment remains constant for two consecutivereadings. In general, not more than two spinnings are required.8.7 The temperature of the sample during the entire centri-fuging procedure shall be maintained at
