1、Designation: D8181 18Standard Specification forMicroemulsion Blendstock for Preparing MicroemulsionTest Fuel Oils1This standard is issued under the fixed designation D8181; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year o
2、f 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 specification describes an alcohol-carboxylic acidblendstock which is to be blended with fuel oils to produce a
3、microemulsion of inverse micelles that is to be used as a testfuel oil.NOTE 1Microemulsion blendstocks shall not include substances suchas raw vegetable oil triglycerides. Refer to Appendix X2.1.2,Composition, for details.1.1.1 The microemulsion blendstock shall be stored inspecial facilities and dr
4、ums or tanks that are suited for lowflashpoint liquids and oxygenated products.1.2 The microemulsion blendstock is to be blended withfuel oils to produce a microemulsion test fuel oil that isintended for testing and demonstration purposes in specialtyapplications such as compression-ignition engine
5、and burnerfuel applications.NOTE 2Typical fuel oils that could be used for blending withmicroemulsion blendstock are fuels that comply with Specifications D975and D396 and may contain up to5%byvolume biodiesel.NOTE 3Testing with test fuels containing 10 % microemulsionblendstock using B5 as a base f
6、uel did not show any detrimental changesto specified fuel properties relative to B0 base fuels, but can impairmeasurement of microemulsion blendstock concentration.1.2.1 The microemulsion test fuel oil (to be made from thisblendstock) is to be used for demonstration purposes only inspecific equipmen
7、t and vehicles that are suited for use with lowflashpoint fuels and oxygenated fuels such as ethanol.NOTE 4The low flash point of this blendstock relative to conventionaldiesel fuel increases certain hazards during storage and distribution.1.3 Nothing in this specification shall preclude observanceo
8、f federal, state, or local regulations, which may be morerestrictive.1.4 The values stated in SI units are to be regarded asstandard. The values given in parentheses after SI units areprovided for information only and are not considered standard.1.5 This standard does not purport to address all of t
9、hesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.6 This international standard was developed in acco
10、r-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 AST
11、M Standards:2D97 Test Method for Pour Point of Petroleum ProductsD130 Test Method for Corrosiveness to Copper from Petro-leum Products by Copper Strip TestD396 Specification for Fuel OilsD445 Test Method for Kinematic Viscosity of Transparentand Opaque Liquids (and Calculation of Dynamic Viscos-ity)
12、D664 Test Method for Acid Number of Petroleum Productsby Potentiometric TitrationD665 Test Method for Rust-Preventing Characteristics ofInhibited Mineral Oil in the Presence of WaterD974 Test Method for Acid and Base Number by Color-Indicator TitrationD975 Specification for Diesel Fuel OilsD3242 Tes
13、t Method for Acidity in Aviation Turbine FuelD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4175 Terminology Relating to Petroleum Products, LiquidFuels, and LubricantsD4625 Test Method for Middle Distillate Fuel StorageStability at 43 C (110 F)D4806 Specification for Denature
14、d Fuel Ethanol for Blend-ing with Gasolines for Use as Automotive Spark-IgnitionEngine Fuel1This specification is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.E0 on Burner, Diesel, Non-Aviation Gas
15、 Turbine, and MarineFuels.Current edition approved July 1, 2018. Published July 2018. DOI: 10.1520/D8181-18.2For 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 stan
16、dards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Dec
17、ision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1D6584 Test Method for Determination of TotalMonoglycerides, Total Diglycerides, Total Triglycerides,and Free and Total Gly
18、cerin in B-100 Biodiesel MethylEsters by Gas ChromatographyD6751 Specification for Biodiesel Fuel Blend Stock (B100)for Middle Distillate FuelsD7042 Test Method for Dynamic Viscosity and Density ofLiquids by Stabinger Viscometer (and the Calculation ofKinematic Viscosity)D7545 Test Method for Oxidat
19、ion Stability of Middle Dis-tillate FuelsRapid Small Scale Oxidation Test (RSSOT)D7862 Specification for Butanol for Blending with Gasolinefor Use as Automotive Spark-Ignition Engine Fuel3. Terminology3.1 For definitions of terms used in this test method, refer toTerminology D4175.3.2 Definitions:3.
20、2.1 biodiesel, nfuel comprised of mono-alkyl esters oflong chain fatty acids derived from vegetable oils or animalfats, designated B100.3.2.2 higher alcohols, naliphatic alcohols of the generalformula CnH2n+1OH with n being 2 to 8.3.2.3 surfactants, nsurface active molecular species thatexhibit both
21、 water-soluble and oil-soluble properties, and affectthe physical behavior at the interface between water and oilphases.3.3 Definitions of Terms Specific to This Standard:3.3.1 inverse micelle, nan aggregate of surfactant mol-ecules dispersed in a non-polar liquid where the hydrophilichead groups ar
22、e oriented at the center with the hydrophobictails extending out.3.3.2 microemulsion blendstock, na mixture of aqueoussolution and surfactant(s) that when blended into hydrocarbondiesel fuel oil forms an isotropic and thermodynamically stablesystem with dispersed droplet diameters varying from 1 nm
23、to100 nm.3.3.3 microemulsion test fuel oil, ndispersion made ofmicroemulsion blendstock in a liquid hydrocarbon fuel that isan isotropic and thermodynamically stable system with dis-persed droplet diameter varying from 1 nm to 100 nm.3.3.4 oxygenate, nan oxygen-containing, ashless, organiccompound,
24、such as an alcohol or ester, which can be used as afuel or fuel supplement.3.3.4.1 DiscussionBoth alcohols such as ethanol and sur-factants such as long-chain carboxylic acids are oxygenates.3.3.5 test fuel, na homogeneous mixture of blendstocksand fuel additives meeting all specification and regula
25、toryrequirements for its intended use at the location where sold.4. Requirements4.1 Microemulsion blendstock shall be a mixture of aqueousalcohol solution and surfactants that conforms to the require-ments in Table 1.4.1.1 The alcohol component shall be alcohols containingtwo carbons and higher. Alc
26、ohols shall comply with existingstandards, if any exist. For example, ethanol shall comply withthe requirements of denatured fuel ethanol in SpecificationD4806, and butanol shall comply with the requirements of fuelbutanol in Specification D7862.4.1.2 The surfactant component shall have total glycer
27、inless than 0.48 % by mass and free glycerin less than 0.04 % bymass, as determined by Specification D6751. See AppendixX2.1.2 for guidance.5. Workmanship, Finish, and Appearance5.1 The blendstock shall be visually free of undissolvedwater, sediment, and suspended matter. It shall be visually cleara
28、nd bright.5.2 If sediment or phase separation appears, the blendstockshall not be used.6. Keywords6.1 biofuel; blendstock; diesel alternative; inverse micelle;micelle; microemulsion; oxygenated diesel; renewable fuel;test fuel oilsTABLE 1 Requirements for Microemulsion BlendstockProperty Limit Test
29、MethodKinematic Viscosity, 40 C, cSt 9.0 to 12.0 ASTM D7042ACopper strip corrosion, max No. 1 ASTM D130Iron Corrosion, maxAASTM D665Oxidation stability, 140 C, 700 kPa,minutesReport ASTM D7545Pour Point, C 13 to 15 ASTM D97Blending Requirement(1) Formation of microemulsiontest fuelsize of inverse mi
30、celles,nm, max50 See Annex A1 and Annex A2(2) Stability of blendstock in certifi-cation fuel, days, min60 See Annex A3ATest Method D445 may also be used. Test Method D7042 is the referee testmethod.D8181 182ANNEXES(Mandatory Information)A1. VERIFICATION OF FORMATION OF MICROEMULSION TEST FUELA1.1 Sc
31、opeA1.1.1 Annex A1 specifies a method to test that the blend-stock was made correctly and will behave as expected whenblended into a fuel at a concentration of 5 % to 45 %.A1.2 General RequirementsA1.2.1 Microemulsion blendstock shall be at room tempera-ture (20 C to 25 C) for at least 1 h before te
32、sting.A1.2.1.1 If microemulsion blendstock was at a reducedtemperature prior to testing, the container shall be well mixed.Once any air bubbles settle, the microemulsion blendstockshall be clear.A1.2.1.2 Diesel used for testing shall conform to Specifica-tion D975.A1.3 Test ProcedureA1.3.1 Add 2 mL
33、of microemulsion blendstock to a 50 mLconical tube.A1.3.2 Add 2.5 mL of diesel to the tube.A1.3.3 Agitate the tube to mix the sample.A1.3.4 Allow the sample to sit for 5 min.A1.3.5 Ensure the mixture is clear and bright. This repre-sents blending at 44 %.A1.3.6 Add an additional 2 mL of diesel to th
34、e tube.A1.3.7 Agitate the tube to mix the sample.A1.3.8 Allow the sample to sit for 5 min.A1.3.9 Ensure the mixture is monophasic and the clarity ofdiesel. This represents blending at 31 %.A1.3.10 Add an additional 6 mL of diesel to the tube.A1.3.11 Agitate the tube to mix the sample.A1.3.12 Allow t
35、he sample to sit for 5 min.A1.3.13 Ensure the mixture is monophasic and the clarity ofdiesel. This represents blending at 16 %.A1.3.14 Add an additional 26.5 mL of diesel to the tube.A1.3.15 Agitate the tube to mix the sample.A1.3.16 Allow the sample to sit for 5 min.A1.3.17 Ensure the mixture is mo
36、nophasic and the clarity ofdiesel. This represents blending at 5 %.A1.3.18 Retain the 5 % blended test fuel for 24 h at roomtemperature.A1.3.19 Ensure the mixture is monophasic and the clarity ofdiesel.A1.4 ResultsA1.4.1 If all of the above samples are monophasic and theclarity of diesel, the microe
37、mulsion blendstock passes and isconfirmed to form micelles in a hydrocarbon solution.A1.4.2 Appendix X1 provides information on correlatingconcentration of the blendstock to the inverse micelle size.A2. VERIFICATION OF MICELLE FORMATION BY DYNAMIC LIGHT SCATTERINGA2.1 ScopeA2.1.1 Annex A2 specifies
38、a method to test that the blend-stock forms micelles.A2.2 ApparatusA2.2.1 Any dynamic light scattering (DLS) instrumentcapable of measuring in the 2 nm to 200 nm range shall besufficient.A2.2.2 Cuvettes shall be made of a material that is compat-ible with all components of the test fuel.A2.3 Procedu
39、reA2.3.1 A test fuel shall be made of 10 % microemulsionblendstock in diesel in sufficient quantity to fill the cuvette.A2.3.2 Before adding the test fuel to the cuvette, add 0.5 %water by volume and mix well.A2.3.2.1 If the sample becomes cloudy, the test fails.A2.3.3 Sample shall retain the same c
40、larity as the originaltest fuel.A2.3.4 Samples shall be measured in triplicate and averagevalues taken.A2.4 ResultsA2.4.1 The average size of the inverse micelles shall berecorded.A2.4.2 Use Appendix X1 as guidance of typical sizesobserved.D8181 183A3. VERIFICATION OF STABILITY OF BLENDSTOCK IN CERT
41、IFICATION FUELA3.1 ScopeA3.1.1 Annex A3 specifies a method to test that long-termstability of a blendstock in certification fuel.A3.2 ApparatusA3.2.1 Oven, of adequate size to fit the samples. The ovenshould be adequately vented.A3.2.2 ThermometerAny temperature-measuring devicemay be used, provided
42、 it can accurately indicate the tempera-ture to within 0.1 C or 0.2 F and properly be recorded.A3.3 Accelerated Aging TheoryA3.3.1 Aging a sample at an elevated temperature is ex-pected to expedite the aging process.A3.3.2 According to Test Method D4625, 14 days at 43 Cshould be equivalent to 60 day
43、s at room temperature.A3.3.3 To expedite aging more, the temperature shall beheld at 55 C for 7 days.A3.4 ProcedureA3.4.1 BaselineBefore the aging process is begun, thefollowing should be measured:A3.4.1.1 Acid NumberTest Method D664. Test MethodsD3242 or D974 may also be used. Test Method D664 shal
44、l bethe referee test method.A3.4.1.2 Visual inspection of clarity.A3.4.2 Aging at 55 C:A3.4.2.1 50 mL of test fuel shall be added to three glassvials whose caps provide adequate sealing at 55 C.(1) Glass vials should not be filled to the top and should beleft with adequate headspace.A3.4.2.2 Record
45、the temperature of the oven and verify it iswithin 1 C of 55 C.A3.4.2.3 Over the next 7 days, verify that the oven hasremained within 1 C of 55 C.A3.4.2.4 After 7 days at 55 C, remove the vials from theoven.A3.4.2.5 Allow to cool to room temperature before testingthe aged samples.A3.4.3 Aged Samples
46、After the samples have been agedfor 7 days, the following tests shall be completed:A3.4.3.1 Acid NumberTest Method D664. Test MethodsD3242 or D974 may also be used. Test Method D664 shall bethe referee test method.A3.4.3.2 Visual inspection of clarity.A3.4.4 Results:A3.4.4.1 Changes of more than 5 %
47、 in the acid numberresults in a failed age-stability test for the blendstock incertification fuel.A3.4.4.2 Formation of a precipitate or a decrease in visualclarity also result in a failed age-stability test.APPENDIXES(Nonmandatory Information)X1. INVERSE MICELLE PROPERTIESX1.1 Micelle Structure and
48、 MorphologyWhen splash-blended into diesel fuel oil at volumes ranging from5%to45% by volume, the resulting fuel blend forms a clear andthermodynamically stable homogeneous microemulsion con-sisting of ellipsoid micelles with geometric diameters thataverage approximately 3 nanometers. The geometric
49、diameteris the diameter of a sphere of equal total volume as theellipsoid. These samples can absorb additional water (roughlydouble initial concentrations), resulting in micelle swelling tonearly 15 nm diameter before the system starts to becomeunstable.3Micelle size and structure was characterized bydynamic light scattering (DLS), which measures the fluctua-tions in intensity of scattered light of diffusing particles, andsmall angle neutron scattering (SANS), which detects differ-ences in neutron scattering densities between hydrogen anddeute
