1、Designation: D7451 08a (Reapproved 2013)Standard Test Method forWater Separation Properties of Light and Middle Distillate,and Compression and Spark Ignition Fuels1This standard is issued under the fixed designation D7451; the number immediately following the designation indicates the year oforigina
2、l 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 tendencyof water and
3、 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.1.2 This test
4、method applies primarily to gasoline, diesel,kerosine, and distillate grades of gas turbine, marine, homeheating oils and furnace fuels (see Specifications D396, D975,D2880, D3699, D4814, and D6985). For fuel components suchas biodiesel or alcohol, refer to X1.2 and X1.3.1.3 This test method is not
5、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.1.4 This test method is not meant for testing of fuelscontaining large amounts of aqueous soluble components, suchas E85, or for testi
6、ng of water emulsified fuels, or for testing ofaviation fuels.1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is th
7、eresponsibility 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.2. Referenced Documents2.1 ASTM Standards:2D86 Test Method for Distillation of Petroleum Products atAtmospheric PressureD396 Spec
8、ification for Fuel OilsD975 Specification for Diesel Fuel OilsD1193 Specification for Reagent WaterD2274 Test Method for Oxidation Stability of Distillate FuelOil (Accelerated Method)D2880 Specification for Gas Turbine Fuel OilsD3699 Specification for KerosineD4057 Practice for Manual Sampling of Pe
9、troleum andPetroleum ProductsD4176 Test Method for Free Water and Particulate Contami-nation in Distillate Fuels (Visual Inspection Procedures)D4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsD4814 Specification for Automotive Spark-Ignition EngineFuelD6985 Specification for M
10、iddle Distillate Fuel OilMilitary Marine Applications (Withdrawn 2010)32.2 ASTM Adjuncts:Distillate Fuel Bar Chart4Fuel Clarity Rating Standard53. 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
11、 the fuel/water inter-face is covered with more than 50% scum that extends intoeither of the two layers or forms an emulsion (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 Te
12、rms Specific to This Standard: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, 2013. Published August 2013. Origina
13、llyapproved in 2008. Last previous edition approved in 2008 as D7451 08a. DOI:10.1520/D7451-08AR13.2For 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 Doc
14、ument Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.4Available from ASTM International Headquarters. Order Adjunct No.ADJD417601. Original adjunct produced in 1991.5Available from ASTM International Headquarters. Order Adjunct No.
15、ADJD7451. Original adjunct produced in 2008.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2.1 interface condition rating, nqualitative assessmentof the tendency of a mixture of water and fuel to form interfacefilms or precipitates
16、.3.2.2 water 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
17、water returned 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 thes
18、ample.4. Summary 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 app
19、ear-ance of 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 com
20、promised by 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
21、.2 Interface 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
22、filters and 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 ra
23、ting. The dimensions 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 1Contact Subcommittee D02.14 for a
24、list of possible suppliersfor the tubes and caps.6.2 Shaking Apparatus (Optional)An explosionproof ap-paratus 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 orie
25、ntation as outlined in 10.2 is acceptable.NOTE 2 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,
26、respec-tively. (See 10.4.2.)NOTE 3If 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.TABLE 1 Fuel Clarity RatingsNOTE 1These rating systems have been determined for use in t
27、he tubes described in 6.1. The use of narrower or wider tube 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 tub
28、e, orVolume markings and numbers on glassware readily readable 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
29、on a white background not readable through tube, orVolume markings 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 t
30、ube6 OpaqueD7451 08a (2013)27. Reagents7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifi
31、cations are available. Other 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 wate
32、r or water ofequivalent or greater purity. Any type of water specified inSpecification D1193 may be used.7.3 Glass Cleaning SolutionAcidic non-chromium con-taining cleaning solution. (WarningCorrosive. Health haz-ard. Oxidizing agent.)NOTE 4Contact Subcommittee D02.14 for a list of possible supplier
33、sfor the glass cleaning solutions.7.4 Cleaning Solvent, Reagent GradeTrisolvent (TAM)(as defined by Test Method D2274), n-hexane, n-heptane,methylbenzene, dimethylbenzene, isopropyl alcohol,methanol, or acetone. (WarningFlammable. Health hazard.)8. Sampling8.1 Sampling shall be consistent with the p
34、rocedures ofPractice D4057 or Practice D4177.8.2 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
35、 containers shall 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 5Test met
36、hod results are known 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 conta
37、minated with particulate 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
38、 solvent as per 7.4. 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 clea
39、ning solution and 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 practi
40、ce. Follow-ing cleaning 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
41、a manner such that the glass is evenly water-wet, withno voids or un-wetted areas immediately thereafter, is consid-ered adequately cleaned.NOTE 6Inadequately cleaned glassware used in this test can givemisleading indications of fuel contaminants. Use only test tubes that areadequately cleaned.10. P
42、rocedure10.1 Add 80 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 seale
43、d test tube for 2 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 brea
44、k any emulsion that 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 laye
45、r to the nearest0.5 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 D4176.)10.4.3 The degree of separation of the two phases inaccordance with Table 2.10.4.
46、4 The condition of 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 th
47、e nearest 0.5 mL.TABLE 2 Fuel-Water Separation RatingRating Appearance1 Complete absence of all emulsions, or precipitates, or both,within either 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,
48、 within either layer or upon thefuel layer, and droplets in the water layer or adhering to the testtube walls, or both, excluding the walls above the fuel layerD7451 08a (2013)311.1.2 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 th
49、e condition of the interface (see Table 3).11.1.5 Type of water or aqueous phase used in the test, ifother than distilled water.12. 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 ratings 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.
