1、Designation: D 1796 04Designation: Manual of Petroleum Measurement Standards (MPMS), Chapter 10.6An American National StandardStandard Test Method forWater and Sediment in Fuel Oils by the Centrifuge Method(Laboratory Procedure)1This standard is issued under the fixed designation D 1796; the number
2、immediately following the 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 (e) indicates an editorial change since the last revision or reapproval.This standa
3、rd has been approved for use by 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
4、 oils ordistillate fuel 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 MethodD 473 (API MPMS Chapter 10.1) may be used.NOTE 2API MPMS Chapter 10.6 (Test
5、Method D 1796) along withAPI MPMS Chapter 10.3 (Test Method D 4007) formerly superseded APIStandard 2548.1.2 The values stated in SI units are to be regarded as thestandard.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 concern
6、s, 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. For a specificprecautionary statement, see 6.1.2. Referenced Documents2.1 ASTM Stand
7、ards:2D95 Test Method for Water in Petroleum Products andBituminous Materials by Distillation (API MPMS Chapter10.5)D 473 Test Method for Sediment in Crude Oils and FuelOils by the Extraction Method (API MPMS Chapter 10.1)D 4007 Test Method for Water and Sediment in Crude Oilby the Centrifuge Method
8、 (Laboratory Procedure) (APIMPMS Chapter 10.3)D 4057 Practice for Manual Sampling of Petroleum andPetroleum Products (API MPMS Chapter 8.1)D 4177 Practice for Automatic Sampling of Petroleum andPetroleum Products (API MPMS Chapter 8.2)D 5854 Practice for Mixing and Handling of LiquidSamples of Petro
9、leum and Petroleum Products (APIMPMS Chapter 8.3)E 542 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 D 4057)MPMS Chapter 8.2 Practice for Automatic Sampling ofPetroleum an
10、d Petroleum Products (ASTM PracticeD 4177)MPMS Chapter 8.3 Practice for Mixing and Handling ofLiquid Samples of Petroleum and Petroleum Products(ASTM Practice D 5854)MPMS Chapter 10.1 Test Method for Sediment in CrudeOils by the Extraction Method (ASTM Test MethodD 473)MPMS Chapter 10.3 Test Method
11、for Water and Sediment inCrude Oil by the Centrifuge Method (Laboratory Proce-dure) (ASTM Test Method D 4007)MPMS Chapter 10.5 Test Method for Water in PetroleumProducts and Bituminous Materials by Distillation(ASTM Test Method D95)1This test method is under the jurisdiction of ASTM Committee D02 on
12、Petroleum 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 Petroleum Measurement.Current edition approved Dec. 1, 2004. Published February 2005. Originallyapproved in 1960. Las
13、t previous edition approved in 2002 as D 1796 97 (2002).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 website.3Publ
14、ished as Manual of Petroleum Measurement Standards. Available from theAmerican Petroleum Institute, 1220 L St., N.W., Washington, DC 20005.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-
15、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 fuel oil and water-saturated tolueneare placed in each of two cone-shaped ce
16、ntrifuge 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 inprocessing. A determination o
17、f water and sediment content isrequired to measure accurately net volumes of actual fuel oil insales, taxation, exchanges, and custody transfers.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 c
18、ontrolled to give a relative 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 t
19、he power source. The trunnion 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 a
20、void unsafe conditions. It 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 a
21、nd heated centrifuges must 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 dischargin
22、g any vapors to a non-hazardous 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 =
23、rcf/d (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 t
24、ips of 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 Tubes:5.2.1 Each centrifuge tube shall be a cone-shaped tube,conforming to the dimensions given in Fig. 1, and ma
25、de ofthoroughly annealed 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 g
26、iven inTable 1 and apply 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 PracticeE 542 using equipment traceable through the National In
27、stitute4Available 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. FIG. 1 Eight-Inch (203-mm) Centrifuge TubeD1796042for Standards and Technology (NIST)6or other nationalstanda
28、rds. Include the verification or certification for eachmark through the 0.5-mL mark; 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 bat
29、h of sufficient depth for immersing the centrifugetube in the vertical position to 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 corr
30、ect sediment andwater content. If temperatures higher than 60C 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
31、 for Methyl-benzenes (Toluenes) or to ISO 5272.(WarningFlammable.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 orrepe
32、ated contact with the skin.)6.1.1 Typical characteristics for this reagent are:Molecular 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 poin
33、t 110.6C.NOTE 5Some oils may require other solvents 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 6 1C (1406 1.8F) but shall be free of suspended water. See Annex A1for the solvent-water saturati
34、on procedure.6.2 Demulsifiers:6.2.1 Where necessary, 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 ac
35、cord-ing to the manufacturers recommendations 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 re
36、quired to obtain analiquot of the contents of any pipe, tank, or other system and toplace them into the laboratory test container.7.2 Only representative samples obtained as specified inPractice D 4057 (API MPMS Chapter 8.1) and Practice D 4177(API MPMS Chapter 8.2) shall be used for this test metho
37、d.7.3 Practice D 5854 (API MPMS Chapter 8.3) containsadditional information on sampling and homogenization effi-ciency of an untested mixer. Do not use this test methodwithout strict adherence to Practice D 5854 (API MPMSChapter 8.3).8. Procedure8.1 Fill each of two centrifuge tubes (5.2) to the 50-
38、mLmark with the well-mixed sample directly from the samplecontainer. Using a pipette, 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 stoppers
39、on the tubes and immerse the tubes to the 100-mL mark for10 min in the bath maintained 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
40、(140F) are approximately double thoseat 40C (104F). Consequently, invert the tubes at 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
41、 tubes and stoppers do not touch adjacent 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 therelation
42、ship between diameter of swing, relative centrifugalforce, and revolutions per minute). 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 immed
43、iately brought to a verticalposition after the centrifuge stops because the results 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 a
44、bove the 1-mL graduations. Below0.1 mL, estimate to the nearest 0.025 mL (see Fig. 2). 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., S
45、top 3460, Gaithersburg, MD 20899-3460.TABLE 1 Centrifuge Tube Calibration Tolerances 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
46、60.10Above 3.0 to 5.0 0.50 60.20Above 5.0 to 10 1.00 60.50Above 10 to 25 5.00 61.00Above 25 to 100 25.00 61.00D1796043volume 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
47、same rate.8.5 Repeat this operation until the combined volume ofwater and sediment remains constant for two consecutivereadings. In general, not more than two spinnings are required.8.6 If the difference between the final volumes is not greaterthan one subdivision on the centrifuge tube (see Table 1
48、), 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, greater than 0.025 mL, the readings are inadmi
49、ssible. 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 determination shall be repeated.9.2 Calculate the water and sediment of the sample asfollows:V 5 V11 V2(5)where:V = water and sediment of the sample (the test result),% V/V,V1= final volume of water and sediment per 50
