1、Designation: D8181 18bStandard 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
2、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. Scope*1.1 This specification describes an alcohol-carboxylic acidblend, referred to as the microemulsion blendstock.NOTE 1Mi
3、croemulsion blendstocks shall not include substances suchas raw vegetable oil triglycerides. Refer to Appendix X2.1.2,Composition, for details.1.1.1 WarningThe microemulsion blendstock should bestored in facilities and equipment designed for oxygenated andlow flashpoint liquids.1.2 The microemulsion
4、 blendstock is to be blended withfuel oils to produce a microemulsion test fuel oil that consistsof inverse micelles.NOTE 2While no fuel standard currently exists for a microemulsiontest fuel oil, work to develop one is underway.NOTE 3Typical fuel oils that could be used for blending withmicroemulsi
5、on blendstock are fuels that comply with Specifications D975and D396 and may contain up to5%byvolume biodiesel.NOTE 4Testing with test fuels containing 10 % microemulsionblendstock using B5 as a base fuel did not show any detrimental changesto specified fuel properties relative to B0 base fuels, but
6、 can impairmeasurement of microemulsion blendstock concentration.1.2.1 The microemulsion test fuel oil (to be made from thisblendstock) is to be used for testing and demonstrationpurposes only in specific equipment and vehicles that are suitedfor or have been equipped with safety precautions for use
7、 withlow flashpoint fuels and oxygenated fuels such as ethanol.Minimum safety precautions may include flame arrestors andgrounding straps.NOTE 5The low flash point of this blendstock relative to conventionaldiesel fuel increases certain hazards during storage and distribution.1.3 Nothing in this spe
8、cification shall preclude observanceof 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
9、 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, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.6 This interna
10、tional standard was developed in accor-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) Com
11、mittee.2. Referenced Documents2.1 ASTM 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 (a
12、nd Calculation of Dynamic Viscos-ity)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 Specif
13、ication for Diesel Fuel OilsD3242 Test 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 Storage1This specification
14、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 Turbine, and MarineFuels.Current edition approved Dec. 1, 2018. Published January 2019. Originallyapproved in
15、2018. Last previous edition approved in 2018 as D8181 18a. DOI:10.1520/D8181-18B.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
16、 onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright 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
17、standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1Stability at 43 C (110 F)D4806 Specification for Denatured Fuel Ethanol for Blend-in
18、g with Gasolines for Use as Automotive Spark-IgnitionEngine FuelD6584 Test Method for Determination of TotalMonoglycerides, Total Diglycerides, Total Triglycerides,and Free and Total Glycerin in B-100 Biodiesel MethylEsters by Gas ChromatographyD6751 Specification for Biodiesel Fuel Blend Stock (B10
19、0)for Middle Distillate FuelsD7042 Test Method for Dynamic Viscosity and Density ofLiquids by Stabinger Viscometer (and the Calculation ofKinematic Viscosity)D7545 Test Method for Oxidation Stability of Middle Dis-tillate FuelsRapid Small Scale Oxidation Test (RSSOT)D7862 Specification for Butanol f
20、or 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:3.2.1 biodiesel, nfuel comprised of mono-alkyl esters oflong chain fatty acids derived from vegetable oils or animal
21、fats, 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 water-soluble and oil-soluble properties, and affectthe physical behavior at the interface between water and oilp
22、hases.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 are oriented at the center with the hydrophobictails extending out.3.3.2 microemulsion blendstock, na mixture of aqu
23、eoussolution and surfactant(s) that when blended into hydrocarbondiesel fuel oil forms an isotropic and thermodynamically stablesystem with dispersed droplet diameters varying from 1 nm to100 nm.3.3.3 microemulsion test fuel oil, ndispersion made ofmicroemulsion blendstock in a liquid hydrocarbon fu
24、el 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, such as an alcohol or ester, which can be used as afuel or fuel supplement.3.3.4.1 DiscussionBoth alcohols such as
25、 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 regulatoryrequirements for its intended use at the location where sold.4. Requirements4.1 Microemulsion blendstock shall
26、 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. Alcohols shall comply with existingstandards, if any exist. For example, ethanol shall comply withthe requirements of
27、 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 glycerinless than 0.48 % by mass and free glycerin less than 0.04 % bymass, as determined by Specification D6584. See Ap
28、pendixX2.1.2 for guidance.5. Workmanship, Finish, and Appearance5.1 The blendstock shall be visually free of undissolvedwater, sediment, and suspended matter. It shall be visually clearand bright.5.2 If sediment or phase separation appears, the blendstockshall not be used.6. Keywords6.1 biofuel; ble
29、ndstock; diesel alternative; inverse micelle;micelle; microemulsion; oxygenated diesel; renewable fuel;test fuel oilsTABLE 1 Requirements for Microemulsion BlendstockProperty Limit Test MethodKinematic Viscosity, 40 C, cSt 9.0 to 12.0 ASTM D7042ACopper strip corrosion, max No. 1 ASTM D130Iron Corros
30、ion, 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 micelles,nm, max50 See Annex A1 andAnnex A2(2) Stability of blendstock in certifi-cation fuel, days, min60 See Annex
31、 A3ATest Method D445 may also be used. Test Method D7042 is the referee testmethod.D8181 18b2ANNEXES(Mandatory Information)A1. VERIFICATION OF FORMATION OF MICROEMULSION TEST FUELA1.1 ScopeA1.1.1 Annex A1 specifies a method to test that the blend-stock was made correctly and will behave as expected
32、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 testing.A1.2.1.1 If microemulsion blendstock was at a reducedtemperature prior to testing, the container shall be we
33、ll 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 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
34、 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 the 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 mixtur
35、e 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 the sample to sit for 5 min.A1.3.13 Ensure the mixture is monophasic and the clarity ofdiesel. This represents blen
36、ding 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 monophasic and the clarity ofdiesel. This represents blending at 5 %.A1.3.18 Retain the 5 % blended test fuel for 24
37、 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 microemulsion blendstock passes and isconfirmed to form micelles in a hydrocarbon solution.A1.4.2 Appendix X1 provides i
38、nformation 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 a method to test that the blend-stock forms micelles.A2.2 ApparatusA2.2.1 Any dynamic light scattering (DLS) instr
39、umentcapable 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 ProcedureA2.3.1 A test fuel shall be made of 10 % microemulsionblendstock in diesel in sufficient quantity to fill the cu
40、vette.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 clarity as the originaltest fuel.A2.3.4 Samples shall be measured in triplicate and averagevalues taken.A2.4 Result
41、sA2.4.1 The average size of the inverse micelles shall berecorded.A2.4.2 Use Appendix X1 as guidance of typical sizesobserved.D8181 18b3A3. VERIFICATION OF STABILITY OF BLENDSTOCK IN CERTIFICATION FUELA3.1 ScopeA3.1.1 Annex A3 specifies a method to test that a micro-emulsion blendstock has adequate
42、long-term stability for use ina microemulsion test 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 it can accurately indicate the tempera-ture to within 0.1 C or 0.2 F and
43、 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 days at room temperature.A3.3.3 To expedite aging more, the temperature shal
44、l 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 shall bethe referee test method.A3.4.1.2 Visual inspection of clarity.A3.4.2
45、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 the temperature of the oven and verify it iswithin 1 C of 55 C.A3.4.2.3 O
46、ver 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 SamplesAfter the samples have been agedfor 7 days, the following tests shall be
47、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 % in the acid numberresults in a failed age-stability test for the blendst
48、ock 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 MorphologyWhen splash-blended into diesel fuel oil at volumes ranging fr
49、om5%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 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 sc
