1、Designation: D 7451 08An American National StandardStandard Test Method forWater Separation Properties of Light and Middle Distillate,and Compression and Spark Ignition Fuels1This standard is issued under the fixed designation D 7451; the number immediately following the designation indicates the ye
2、ar 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. Scope1.1 This test method covers the evaluation of the tendency
3、of water and fuels with a final boiling point of less than 390C,as measured in Test Method D86, to separate cleanly ratherthan create emulsions when they may contain potential emul-sion forming additives or components, or have been additizedwith potential emulsion forming additives, or components.1.
4、2 This test method applies primarily to gasoline, diesel,kerosine, and distillate grades of gas turbine, marine, homeheating oils and furnace fuels (see Specifications D 396, D 975,D 2880, D 3699, D 4814, and D 6985). For fuel componentssuch as biodiesel or alcohol, refer to X1.2 and X1.3.1.3 This t
5、est method is not meant to certify or qualify fuelsfor sale, but it is intended for use by additive suppliers todetermine the need for demulsifier components in their additivepackages.NOTE 1This test method is not meant for testing of aviation fuels.1.4 The values stated in SI units are to be regard
6、ed asstandard. No other units of measurement are included in thisstandard.1.5 This standard does not purport to address all of thesafety 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
7、 the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D86 Test Method for Distillation of Petroleum Products atAtmospheric PressureD 396 Specification for Fuel OilsD 975 Specification for Diesel Fuel OilsD 1193 Specification for Reagent WaterD 2274 Tes
8、t Method for Oxidation Stability of DistillateFuel Oil (Accelerated Method)D 2880 Specification for Gas Turbine Fuel OilsD 3699 Specification for KerosineD 4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD 4176 Test Method for Free Water and Particulate Con-tamination in Distilla
9、te Fuels (Visual Inspection Proce-dures)D 4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsD 4814 Specification forAutomotive Spark-Ignition EngineFuelD 6985 Specification for Middle Distillate Fuel OilMilitary Marine Applications2.2 ASTM Adjuncts:Distillate Fuel Bar Chart3Fuel
10、 Clarity Rating Standard43. Terminology3.1 Definitions:3.1.1 film, nthin, translucent layer that does not adhere tothe wall of the glass test tube.3.1.2 heavy scum, nassessment that the fuel/water inter-face is covered with more than 50% scum that extends intoeither of the two layers or forms an emu
11、lsion (1 mL or greaterin volume), or both.3.1.3 scum, nlayer thicker than film (up to 1 mL involume) or that adheres to the wall of the glass test tube, orboth.3.2 Definitions of Terms Specific to This Standard:3.2.1 interface condition rating, nqualitative assessmentof the tendency of a mixture of
12、water and fuel to form interfacefilms or precipitates.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.14 on Stability and Cleanliness of Liquid Fuels.Current edition approved May 1, 2008. Publis
13、hed June 2008.2For 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.3Available from ASTM International Headquarters
14、. Order Adjunct No.ADJD417601. Original adjunct produced in 1991.4Available from ASTM International Headquarters. Order Adjunct No.ADJD7451. Original adjunct produced in 2008.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.2 wate
15、r separation rating, nqualitative assessment ofthe tendency of components in the fuel to produce emulsions orprecipitates, or both, in separated fuel and water layers.3.2.3 water volume change, nqualitative indication of thepresence of water-soluble components in fuels, or the decreasein water retur
16、ned during the test due to the formation of scumor emulsions.3.2.3.1 DiscussionFor example, the alcohol component inan ethanol-blended gasoline would be extracted into theaqueous phase, thus increasing the volume of the aqueousphase by the approximate volume of the ethanol present in thesample.4. Su
17、mmary of Test Method4.1 The cleanliness of the glass test tube is tested prior touse in the test.4.2 A sample of the fuel is shaken at room temperatureusing a standardized technique with an aqueous phase inthoroughly cleaned glassware.4.3 The change in volume of the aqueous layer, the appear-ance of
18、 the interface and the clarity of the fuel are reported asan indication of the water separation properties of the fuel.5. Significance and Use5.1 The primary use of this test method is to evaluate newadditive packages in specific fuels to ensure that fuel-waterseparability will not be compromised by
19、 the use of the additivepackage, either at their normal treat rates or at several times theintended treat rate to evaluate the impact of potential overtreat-ment.5.1.1 Water Volume ChangesUsing this technique revealthe presence of water-soluble components, such as alcohols, inthe fuel.5.1.2 Interfac
20、e Condition RatingsUsing this techniquereveal the presence of partially soluble components, such assurfactants, in the fuel.5.2 Additives or contaminants that affect the interface couldharm water separation properties of fuels in equipment andquickly inhibit the free flow of fuel through filters and
21、 injectionequipment, causing a decrease in combustion performance.6. Apparatus6.1 Graduated Glass TubeSealable, blunt-tipped, 100-mLwith12-mL graduations from 1 to 10 mL and 2-mL graduationsfrom 10 to 100 mLnot encompassing the whole diameter of thetube as to interfere with the clarity rating. The d
22、imensions ofthe tube are as follows:6.1.1 Overall length = 200 6 5 mm.6.1.2 Outer diameter of the tube portion = 38 mm.6.1.3 Neck length = 25 mm.6.1.4 Headspace from 100-mL graduation to tube neck = 506 5 mm.6.1.5 Tip length = 30 mm with a 45 taper.NOTE 2Contact Subcommittee D02.14 for a list of pos
23、sible suppliersfor the tubes and caps.6.2 Shaking Apparatus (Optional)An explosionproofapparatus capable of shaking the tubes as prescribed in 10.2 ispreferred for testing consistency. However, any method thatfacilitates shaking at the prescribed stroke length, frequency,and sample orientation as ou
24、tlined in 10.2 is acceptable.NOTE 3 No suitable vendor for such a machine has been identified. Itremains the responsibility of the user to select an apparatus that meetsthese criteria.6.3 Rating ChartThe line card and fuel clarity rating chartfrom ASTM Adjuncts ADJD417601 and ADJD7451, respec-tively
25、. (See 10.4.2.)NOTE 4If the line card is not available or fuel clarity is not readilydiscernible from using the line card, then printed text as described in Table1 may be used to assess fuel clarity.7. Reagents7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise
26、indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,TABLE 1 Fuel Clarity RatingsNOTEThese rating systems have been determined for use in the tubes described in 6.1. The use of narrower or wider tube
27、would give potentiallydifferent ratings than those outlined in the tables.Rating Appearance1 Clear and bright, equal to the base fuel2 Very slight hazeBlack 10 pt bold Times New Roman font on a white background readily readable through tube, orVolume markings and numbers on glassware readily readabl
28、e through tube3 Slight hazeBlack 10 pt bold Times New Roman font on a white background visible but not readable through tube, orVolume marking and numbers on glassware visible through tube4 Slight hazeBlack 10 pt bold Times New Roman font on a white background not readable through tube, orVolume mar
29、kings and numbers on glassware visible but not readable through tube5 Hazy/translucentBlack 10 pt bold Times New Roman font on a white background not visible through tube, orVolume markings and numbers on glassware barely visible through tube6 OpaqueD7451082where such specifications are available. O
30、ther grades may beused, provided it is first ascertained that the reagent is ofsufficient purity to permit its use without lessening the accu-racy of the determination.7.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean distilled water or water ofequivalent
31、or greater purity. Any type of water specified inSpecification D 1193 may be used.7.3 Glass Cleaning SolutionAcidic non-chromium con-taining cleaning solution. (WarningCorrosive. Health haz-ard. Oxidizing agent.)NOTE 5Contact Subcommittee D02.14 for a list of possible suppliersfor the glass cleaning
32、 solutions.7.4 Cleaning Solvent, Reagent GradeTrisolvent (TAM)(as defined by Test Method D 2274), n-hexane, n-heptane,methylbenzene, dimethylbenzene, isopropyl alcohol, metha-nol, or acetone. (WarningFlammable. Health hazard.)8. Sampling8.1 Sampling shall be consistent with the procedures ofPractice
33、 D 4057 or Practice D 4177.8.2 A sample of at least 100 mL is required to perform thistest.8.2.1 An aliquot of 100 mL may be removed from a largersample for use in this test, provided the container is adequatelyshaken to homogenize the fuel prior to extracting the sample.8.3 Sample containers shall
34、be free from all contaminants.The sample container must be compatible with the hydrocar-bon being sampled. If water is suspected in the hydrocarbon,then lined cans are required to prevent corrosion by-productsfrom contaminating the fuel; otherwise, they are preferred.NOTE 6Test method results are kn
35、own to be sensitive to tracecontamination from sampling containers.8.4 Under no circumstances shall the sample be pre-filteredafter collection. Filtration media can remove surfactants, thedetection of which is one of the purposes of this test method.If the test fuel sample is contaminated with parti
36、culate matter,allow it to settle before testing.9. Preparation of Apparatus9.1 Clean the test tubes thoroughly before carrying out thistest. Only test tubes that are adequately cleaned can be used.9.1.1 Remove traces of fuel from the test tubes and screwcaps by first rinsing with a solvent as per 7.
37、4. Follow this initialrinsing of the tubes with washing in hot, non-ionic detergent,rinsing with deionized water, then with a final rinse withacetone.9.1.2 Following the washing described in 9.1.1, immerse thetest tubes in a glass cleaning solution described in 7.3. The typeof cleaning solution and
38、conditions for its use may be estab-lished in each laboratory. The criterion for satisfactory cleaningshall be a matching of the quality of that obtained with chromicacid cleaning solution. The use of a cleaning solution such asthat described in 7.3 is the reference cleaning practice. Follow-ing cle
39、aning with the glass cleaning solution, rinse with tapwater, then distilled water and drain.9.1.3 To check for proper cleanliness, completely fill thetube with distilled water, or buffer solution, then rapidly pourout the contents keeping the tube inverted. Glassware thatdrains in a manner such that
40、 the glass is evenly water-wet, withno voids or un-wetted areas immediately thereafter, is consid-ered adequately cleaned.NOTE 7Inadequately cleaned glassware used in this test can givemisleading indications of fuel contaminants. Use only test tubes that areadequately cleaned.10. Procedure10.1 Add 8
41、0 6 1 mL at ambient temperature, typically 18 to30C, of the fuel to be tested to the test tube. Measure 20 6 1mL of water or the desired aqueous phase, also at ambienttemperature, typically 18 to 30C, into the test tube. Seal thetest tube with a clean screw cap.10.2 Shake the sealed test tube for 2
42、min 6 5 s, two to threestrokes per second using 12 to 25-cm length strokes in astraight-line horizontal plane orientation, thus causing thefluids to roll from end to end. (WarningTake care to avoida swirling motion during shaking of the test tube, sinceswirling action tends to break any emulsion tha
43、t might beformed.)10.3 Immediately place the test tube on a vibration-freesurface, and allow the contents to settle, undisturbed, for 5 min.10.4 Without picking up the test tube, record the followingwhile viewing the test tube in diffused light:10.4.1 The volume of the aqueous layer to the nearest0.
44、5 mL.10.4.2 The visual rating of the fuel using the line card andfuel clarity rating chart from ASTM Adjuncts ADJD417601and ADJD7451, respectively, as described in Table 1. (See alsoTest Method D 4176.)10.4.3 The degree of separation of the two phases inaccordance with Table 2.10.4.4 The condition o
45、f the interface in accordance withTable 3. The interface of the backlit sample should be viewedat an angle of 45.11. Report11.1 The report shall include a reference to this test methodand the following:11.1.1 Total volume of the aqueous layer (not includingunresolved emulsion) to the nearest 0.5 mL.
46、11.1.2 Rating of the fuel clarity (see Table 1).11.1.3 Rating of the degree of separation (see Table 2).11.1.4 Rating of the condition of the interface (see Table 3).11.1.5 Type of water or aqueous phase used in the test, ifother than distilled water.TABLE 2 Fuel-Water Separation RatingRating Appear
47、ance1 Complete absence of all emulsions, or precipitates, or both, withineither layer or upon the fuel layer2 Same as Rating No. 1, except small air bubbles or small waterdroplets in the fuel layer3 Emulsions or precipitates, or both, within either layer or upon thefuel layer, and droplets in the wa
48、ter layer or adhering to the testtube walls, or both, excluding the walls above the fuel layerD745108312. Precision and Bias12.1 PrecisionIt is not practical to specify the precision ofthe fuel-water separation rating, interface condition rating, orfuel clarity rating because the results of the rati
49、ngs described inTables 1-3, respectively, are purely qualitative. The tablesassign numbers to descriptions of fuel-water separation, inter-face condition and fuel clarity ratings as a convenient guide toqualitative ratings.12.2 BiasThis test method has no bias because waterseparation properties as defined only in terms of this testmethod.13. Keywords13.1 compression ignition fuel; demulsibility; diesel fuel;emulsion forming; fuel contaminants; fuel water interface;gasoline; light distillate fuel; middle distillate fuel; non-aviation fuel; spark ign
