1、Designation: D1796 11 (Reapproved 2016)Manual of Petroleum Measurement Standards (MPMS), Chapter 10.6Standard Test Method forWater and Sediment in Fuel Oils by the Centrifuge Method(Laboratory Procedure)1This standard is issued under the fixed designation D1796; the number immediately following the
2、designation 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.This standard has been approved for us
3、e by agencies of the U.S. Department of Defense.1. Scope1.1 This test method describes the laboratory determinationof water and sediment in fuel oils in the range from 0 % to30 % volume by means of the centrifuge procedure.NOTE 1With some types of fuel oils such as residual fuel oils ordistillate fu
4、el oils containing residual components, it is difficult to obtainwater or sediment contents with this test method. When this situation isencountered, Test Method D95 (API MPMS Chapter 10.5) or Test MethodD473 (API MPMS Chapter 10.1) may be used.NOTE 2API MPMS Chapter 10.6 (Test Method D1796) along w
5、ithAPI MPMS Chapter 10.3 (Test Method D4007) formerly superseded APIStandard 2548.1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.3 This standard does not purport to address all of thesafety concerns, if any, associated w
6、ith 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. For a specificprecautionary statement, see 6.1.2. Referenced Documents2.1 ASTM Standards:2D95 Test Method f
7、or Water in Petroleum Products andBituminous Materials by Distillation (API MPMS Chapter10.5)D473 Test Method for Sediment in Crude Oils and Fuel Oilsby the Extraction Method (API MPMS Chapter 10.1)D4007 Test Method for Water and Sediment in Crude Oil bythe Centrifuge Method (Laboratory Procedure) (
8、APIMPMS Chapter 10.3)D4057 Practice for Manual Sampling of Petroleum andPetroleum Products (API MPMS Chapter 8.1)D4177 Practice for Automatic Sampling of Petroleum andPetroleum Products (API MPMS Chapter 8.2)D5854 Practice for Mixing and Handling of Liquid Samplesof Petroleum and Petroleum Products
9、(API MPMS Chap-ter 8.3)D6304 Test Method for Determination of Water in Petro-leum Products, Lubricating Oils, and Additives by Cou-lometric Karl Fischer TitrationE542 Practice for Calibration of Laboratory VolumetricApparatus2.2 API Standards:3MPMS Chapter 8.1 Practice for Manual Sampling of Petro-l
10、eum and Petroleum Products (ASTM Practice D4057)MPMS Chapter 8.2 Practice for Automatic Sampling ofPetroleum and Petroleum Products (ASTM PracticeD4177)MPMS Chapter 8.3 Practice for Mixing and Handling ofLiquid Samples of Petroleum and Petroleum Products(ASTM Practice D5854)MPMS Chapter 10.1 Test Me
11、thod for Sediment in CrudeOils by the Extraction Method (ASTM Test MethodD473)MPMS Chapter 10.3 Test Method for Water and Sediment inCrude Oil by the Centrifuge Method (Laboratory Proce-dure) (ASTM Test Method D4007)MPMS Chapter 10.5 Test Method for Water in PetroleumProducts and Bituminous Material
12、s by Distillation(ASTM Test Method D95)1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and the API Committee onPetroleum Measurement and is the direct responsibility of Subcommittee D02.02/COMQ the joint ASTM-API Committee on Hydro
13、carbon Measurement forCustody Transfer (Joint ASTM-API). This test method has been approved by thesponsoring committees and accepted by the Cooperating Societies in accordancewith established procedures.Current edition approved June 1, 2016. Published July 2016. Originally approvedin 1960. Last prev
14、ious edition approved in 2011 as D1796 111. DOI: 10.1520/D1796-11R16.2For 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
15、website.3Published as Manual of Petroleum Measurement Standards. Available from theAmerican Petroleum Institute, 1220 L St., N.W., Washington, DC 20005.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States12.3 IP Standard:4Methods Book, App
16、endix 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 fuel oil and water-saturated tolueneare placed in each of two cone-shaped centrifuge tubes. Aftercentrifugation, the volume of the
17、 higher density water andsediment layer at the bottom of the tube is read.4. Significance and Use4.1 The water and sediment content of fuel oil is significantbecause it can cause corrosion of equipment and problems inprocessing. A determination of water and sediment content isrequired to measure acc
18、urately net volumes of actual fuel oil insales, taxation, exchanges, and custody transfers.4.2 This test method may not be suitable for products thatcontain alcohols that are soluble in water. In cases where theimpact on the results may be significant, the user is advised toconsider using another te
19、st method, such as Test MethodD6304.5. Apparatus5.1 Centrifuge:5.1.1 Use a centrifuge capable of spinning two or morefilled cone-shaped 203 mm (8 in.) centrifuge tubes at a speedthat can be controlled to give a relative centrifugal force (rcf)of between 500 and 800 at the tip of the tubes (see 5.1.6
20、).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 support the tubes when the centrifuge is in motio
21、n. 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 sample temperature during the entire process at
22、60 C 6 1 C (140 F 6 1.8 F). The thermostatic control shallbe capable of maintaining the temperature within these limitsand operate safely if there is a flammable atmosphere.5.1.4 Electric powered and heated centrifuges must meet allsafety requirements for use in hazardous areas.NOTE 3Some heated cen
23、trifuges maintain the bowl at a pressureslightly below atmospheric pressure and reduce the hazards associatedwith vapors and gasses, produced by samples and solvents used in thetests, by discharging any vapors to a non-hazardous area.5.1.5 Calculate the speed of the rotating head in revolutionsper m
24、inute (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 (2)where:rcf = relative centrifugal force, andd = diameter of swing measured between tips of oppo
25、sitetubes 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 oppositetubes when in rotating position, mm, orrcf 5 dSr/min265D2(4)where:d = diameter of swing
26、measured between tips of oppositetubes when in rotating position, in.5.2 Centrifuge Tubes:5.2.1 Each centrifuge tube shall be a cone-shaped tube,conforming to the dimensions given in Fig. 1, and made ofthoroughly annealed glass. The graduations, numbered asshown in Fig. 1, shall be clear and distinc
27、t, and the mouth shall4Available from Energy Institute, 61 New Cavendish St., London, WIG 7AR,U.K.5Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org. FIG. 1 Eight-Inch (203 mm) Centrifuge TubeD1796 11 (2016)2be constricted i
28、n shape for closure with a cork or solvent-resistant rubber stopper. Scale error tolerances and the smallestgraduations between various calibration marks are given inTable 1 and apply to calibrations made with air-free water at20 C (68 F), when reading the bottom of the shaded menis-cus.5.2.2 Volume
29、trically verify or gravimetrically certify theaccuracy of the graduation marks, in accordance with PracticeE542 using equipment traceable through the National Institutefor Standards and Technology (NIST)6or other nationalstandards. Include the verification or certification for eachmark through the 0
30、.5 mL mark; of the 1 mL, 1.5 mL, and 2 mLmarks; and of the 50 mL and 100 mL marks. Do not use thetube if the scale error exceeds the applicable tolerance in Table1.5.3 BathThe bath shall be either a solid metal block bathor a liquid bath of sufficient depth for immersing the centrifugetube in the ve
31、rtical position to the 100 mL mark. Provide themeans for maintaining the temperature at 60 C 6 1 C (140 F6 1.8 F). See Note 4.NOTE 4It has been observed for some fuel oils that temperatureshigher than 60 C (140 F) may be required to obtain correct sediment andwater content. If temperatures higher th
32、an 60 C are necessary, they maybe used only with the consent of the parties involved. Water saturation oftoluene may also be carried out at this higher testing temperature. (SeeAnnex A1.)6. Reagents6.1 Toluene, conforming to the IP Specification for Methyl-benzenes (Toluenes) or to ISO 5272. (Warnin
33、gFlammable.Keep away from heat, sparks, and open flame. Vapor harmful.Toluene is toxic. Particular care must be taken to avoidbreathing the vapor and to protect the eyes. Keep containerclosed. Use with adequate ventilation. Avoid prolonged orrepeated contact with the skin.)6.1.1 Typical characterist
34、ics for this reagent are:Molecular weight C6H5CH392.14Color (APHA) 10Boiling range (initial to dry point)A2.0 C (3.6 F)Residue after evaporation 0.001 %Substances darkened by H2SO4passes ACS testSulfur compounds (as S) 0.003 %ARecorded boiling point 110.6 C.NOTE 5Some oils may require other solvents
35、 or solvent-demulsifiercombinations. Those agreed upon between the purchaser and the sellermay be used.6.1.2 The solvent shall be water-saturated at 60 C 6 1C(140 F 6 1.8 F) but shall be free of suspended water. SeeAnnex A1 for the solvent-water saturation procedure.6.2 Demulsifiers:6.2.1 Where nece
36、ssary, use a demulsifier to promote theseparation of water from the sample, to prevent water fromclinging to the walls of the centrifuge tube, and to enhance thedistinctness of the water-oil interface.6.2.2 When using a demulsifier, it should be mixed accord-ing to the manufacturers recommendations
37、and should neverbe added to the volume of sediment and water determined.Always use the demulsifier in the form of a demulsifier-solventstock solution or be premixed with the solvent to be used in thetest.7. Sampling7.1 Sampling is defined as all steps required to obtain analiquot of the contents of
38、any pipe, tank, or other system and toplace them into the laboratory test container.7.2 Only representative samples obtained as specified inPractice D4057 (API MPMS Chapter 8.1) and Practice D4177(API MPMS Chapter 8.2) shall be used for this test method.7.3 Practice D5854 (API MPMS Chapter 8.3) cont
39、ainsadditional information on sampling and homogenization effi-ciency of an untested mixer. Do not use this test methodwithout strict adherence to Practice D5854 (API MPMSChapter 8.3).8. Procedure8.1 Fill each of two centrifuge tubes (5.2) to the 50 mLmarkwith the well-mixed sample directly from the
40、 sample container.Using a pipette, add 50 mL of the water-saturated solvent (6.1).Read the top of the meniscus at both the 50 mL and 100 mLmarks. Stopper the tubes tightly and shake vigorously until thecontents are thoroughly mixed. Loosen the stoppers on thetubes and immerse the tubes to the 100 mL
41、 mark for 10 min inthe bath maintained at 60 C 6 1 C (140 F 6 1.8 F).8.2 Tighten the stoppers and again invert the tubes to ensurethat the oil and solvent are uniformly mixed and shakecautiously. (WarningIn general, the vapor pressures ofhydrocarbons at 60 C (140 F) are approximately doublethose at
42、40 C (104 F). Consequently, invert the tubes at aposition below eye level so that contact will be avoided if thestopper is blown out.)8.3 Place the tubes in the trunnion cups on opposite sides ofthe centrifuge to establish a balanced condition and ensure thatthe tubes and stoppers do not touch adjac
43、ent or opposite tubeswhen in the extended position. Spin for 10 min at a rate,calculated from the equation given in 5.1.6, sufficient toproduce a relative centrifugal force (rcf) of between 500 and800 at the tip of the whirling tubes (see Table 2 for therelationship between diameter of swing, relati
44、ve centrifugal6Available from National Institute of Standards and Technology (NIST), 100Bureau Dr., Stop 3460, Gaithersburg, MD 20899-3460.TABLE 1 Centrifuge Tube Calibration Tolerances for203-mm (8-in.) TubeRange, mL Subdivision, mL Volume Tolerance, mL0 to 0.1 0.05 0.02Above 0.1 to 0.3 0.05 0.03Ab
45、ove 0.3 to 0.5 0.05 0.05Above 0.5 to 1.0 0.10 0.05Above 1.0 to 2.0 0.10 0.10Above 2.0 to 3.0 0.20 0.10Above 3.0 to 5.0 0.50 0.20Above 5.0 to 10 1.00 0.50Above 10 to 25 5.00 1.00Above 25 to 100 25.00 1.00D1796 11 (2016)3force, and revolutions per minute). Maintain the temperature ofthe sample during
46、the entire centrifuging procedure at 60 C 61 C (140 F 6 1.8 F). (See Note 4.)8.4 Immediately after the centrifuge comes to rest followingthe spin (ensure the tubes are immediately brought to a verticalposition after the centrifuge stops because the results may beaffected if the tubes come to rest at
47、 an angle), read and recordthe combined volume of water and sediment at the bottom ofeach tube to the nearest 0.05 mL from 0.1 mL to 1 mLgraduations and to the nearest 0.1 mL above the 1 mL gradu-ations. Below 0.1 mL, estimate to the nearest 0.025 mL (seeFig. 2). If less than 0.025 mL of water and s
48、ediment is visibleand it is not a great enough volume to be considered 0.025 mL,record the volume as less than 0.025 mL. If no water orsediment is visible, record the volume as 0.000 mL. Return thetubes without agitation to the centrifuge and spin for another10 min at the same rate.8.5 Repeat this o
49、peration until the combined volume ofwater and sediment remains constant for two consecutivereadings. In general, not more than two spinnings are required.8.6 If the difference between the final volumes is not greaterthan one subdivision on the centrifuge tube (see Table 1), or,not greater than 0.0025 mL for estimated volumes of 0.10 mLor lower, proceed with the calculation of water and sedimentcontent using Eq 5 as described in Section 9. If the differenceis greater than one subdivision or, for readings of 0.10 orbelow, greate
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