1、Designation: D1796 11Designation: 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 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.This standard has been approved for use by
3、agencies of the Department of Defense.1. Scope*1.1 This test method describes the laboratory determinationof water and sediment in fuel oils in the range from 0 to 30 %volume by means of the centrifuge procedure.NOTE 1With some types of fuel oils such as residual fuel oils ordistillate fuel oils con
4、taining 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 withAPI MPMS
5、 Chapter 10.3 (Test Method D4007) formerly superseded APIStandard 2548.1.2 The values stated in SI units are to be regarded as thestandard.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 with its use
6、. 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 for Water in
7、 Petroleum Products andBituminous Materials by DistillationD473 Test Method for Sediment in Crude Oils and Fuel Oilsby the Extraction MethodD4007 Test Method for Water and Sediment in Crude Oil bythe Centrifuge Method (Laboratory Procedure)D4057 Practice for Manual Sampling of Petroleum andPetroleum
8、 ProductsD4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsD5854 Practice for Mixing and Handling of Liquid Samplesof Petroleum and Petroleum ProductsD6304 Test Method for Determination of Water in Petro-leum Products, Lubricating Oils, and Additives by Coulo-metric Karl Fische
9、r TitrationE542 Practice for Calibration of Laboratory VolumetricApparatus2.2 API Standards:3MPMS Chapter 8.1 Practice for Manual Sampling of Petro-leum and Petroleum Products (ASTM Practice D4057)MPMS Chapter 8.2 Practice for Automatic Sampling ofPetroleum and Petroleum Products (ASTM PracticeD4177
10、)MPMS Chapter 8.3 Practice for Mixing and Handling ofLiquid Samples of Petroleum and Petroleum Products(ASTM Practice D5854)MPMS Chapter 10.1 Test Method 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 C
11、entrifuge Method (Laboratory Proce-dure) (ASTM Test Method D4007)MPMS Chapter 10.5 Test Method for Water in PetroleumProducts and Bituminous Materials by Distillation(ASTM Test Method D95)2.3 IP Standard:4Methods Book, Appendix B Specification for Methylben-zenes (Toluenes)1This test method is under
12、 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 D02.02.10 on Sediment andWater (API MPMS Chapter 10.0).Current edition approved June 1, 2011. Published August 2011. Originally
13、approved in 1960. Last previous edition approved in 2009 as D179604(2009).DOI: 10.1520/D1796-11.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Docume
14、nt Summary page onthe ASTM website.3Published as Manual of Petroleum Measurement Standards. Available from theAmerican Petroleum Institute, 1220 L St., N.W., Washington, DC 20005.4Available from Energy Institute, 61 New Cavendish St., London, WIG 7AR,U.K.1*A Summary of Changes section appears at the
15、 end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.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
16、 in each of two cone-shaped centrifuge tubes. Aftercentrifugation, the volume of the 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 i
17、nprocessing. A determination of water and sediment content isrequired to measure accurately 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 theimpac
18、t on the results may be significant, the user is advised toconsider using another test 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 relat
19、ive centrifugal force (rcf)of between 500 and 800 at the tip of the tubes (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 trun
20、nion cups and cushions shallfirmly support 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. I
21、t shall be capable ofmaintaining the sample temperature during the entire process at60 6 1C (140 6 1.8F). The thermostatic control shall becapable of maintaining the temperature within these limits andoperate safely if there is a flammable atmosphere.5.1.4 Electric powered and heated centrifuges mus
22、t meet allsafety requirements for use in hazardous areas.NOTE 3Some heated centrifuges 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-haz
23、ardous area.5.1.5 Calculate the speed of the rotating head in revolutionsper 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 (2)where:rcf = rela
24、tive 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 oppositetubes when
25、 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 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
26、glass. The graduations, numbered asshown in Fig. 1, shall be clear and distinct, and the mouth shallbe constricted in 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
27、to calibrations made with air-free water at20C (68F), when reading the bottom of the shaded meniscus.5.2.2 Volumetrically verify or gravimetrically certify theaccuracy of the graduation marks, in accordance with PracticeE542 using equipment traceable through the National Institute5Available from Ame
28、rican 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 112for Standards and Technology (NIST)6or other nationalstandards. Include the verification or certification for eachmark through the 0.5-mL ma
29、rk; of the 1, 1.5 and 2-mL marks;and of the 50 and 100-mL marks. Do not use the tube if thescale error exceeds the applicable tolerance in 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 t
30、o the 100-mL mark. Provide themeans for maintaining the temperature at 60 6 1C (140 61.8F). See Note 4.NOTE 4It has been observed for some fuel oils that temperatureshigher than 60C (140F) may be required to obtain correct sediment andwater content. If temperatures higher than 60C are necessary, the
31、y 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. (WarningFlammable.Keep away from
32、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 characteristics for this reagent are:M
33、olecular weight C6H5CH392.14Color (APHA) 10Boiling range (initial to dry point)A2.0C (3.6F)Residue after evaporation 0.001 %Substances darkened by H2SO4passes ACS testSulfur compounds (as S) 0.003 %ARecorded boiling point 110.6C.NOTE 5Some oils may require other solvents or solvent-demulsifiercombin
34、ations. Those agreed upon between the purchaser and the sellermay be used.6.1.2 The solvent shall be water-saturated at 60 6 1C (1406 1.8F) but shall be free of suspended water. See Annex A1for the solvent-water saturation procedure.6.2 Demulsifiers:6.2.1 Where necessary, use a demulsifier to promot
35、e 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 and should neverbe added to the vo
36、lume 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 any pipe, tank, or other system an
37、d 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) containsadditional information on samp
38、ling 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-mLmark with the well-mixed sample directly from the samplecontainer. Using a pipette
39、, add 50 mL of the water-saturatedsolvent (6.1). Read the top of the meniscus at both the 50 and100 mL marks. Stopper the tubes tightly and shake vigorouslyuntil the contents are thoroughly mixed. Loosen the stopperson the tubes and immerse the tubes to the 100-mL mark for 10min in the bath maintain
40、ed at 60 6 1C (140 6 1.8F).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 60C (140F) are approximately double thoseat 40C (104F). Consequently, invert the tubes a
41、t a positionbelow eye level so that contact will be avoided if the stopper isblown 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 adjacent or opposite tubeswhen in the extended posi
42、tion. 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, relative centrifugalforce, and revolutions per minut
43、e). Maintain the temperature ofthe sample during the entire centrifuging procedure at 60 61C (140 6 1.8F). (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
44、may beaffected if the tubes come to rest at 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 to 1-mL graduationsand to the nearest 0.1 mL above the 1-mL graduations. Below0.1 mL, estimate to the nearest 0.025 mL (see Fig. 2
45、). If lessthan 0.025 mL of water and sediment is visible and it is not agreat enough volume to be considered 0.025 mL, record the6Available from National Institute of Standards and Technology (NIST), 100Bureau Dr., Stop 3460, Gaithersburg, MD 20899-3460.TABLE 1 Centrifuge Tube Calibration Tolerances
46、 for203-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 0.50 60.20Above 5.0 to 10 1.00 60.50Above 10 to 25 5.00 61.00A
47、bove 25 to 100 25.00 61.00D1796 113volume as less than 0.025 mL. If no water or sediment isvisible, record the volume as 0.000 mL. Return the tubeswithout agitation to the centrifuge and spin for another 10 minat the same rate.8.5 Repeat this operation until the combined volume ofwater and sediment
48、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
49、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, greater than 0.025 mL, the readings are inadmissible. Ifthis is the case, repeat the determination starting at 8.1.9. Calculation9.1 Record the final volume of water and sediment in eachtube. If the difference between the two readings is greater thanone subdivision on the centrifuge tube (see Table 1)or0.025 mL for readings of 0.10 mL and below, the readings areinadmissible and the
