1、Designation: D7689 11D7689 17Standard Test Method forCloud Point of Petroleum Products and Liquid Fuels (MiniMethod)1This standard is issued under the fixed designation D7689; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the yea
2、r 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 Scope*1.1 This test method covers the determination of the cloud point of petroleum products, biodiesel, and biodies
3、el blends,blendsthat are transparent in layers 40 mm in thickness, using an automatic instrument.1.2 This test method covers the range of cloud point temperatures from -5050 C to +6C.+6 C.1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in
4、this standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.1.5
5、 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade
6、 (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D2500 Test Method for Cloud Point of Petroleum Products and Liquid FuelsD4057 Practice for Manual Sampling of Petroleum and Petroleum ProductsD4177 Practice for Automatic Sampling of Petroleum and Petroleum ProductsD6708 Practice for Statis
7、tical Assessment and Improvement of Expected Agreement Between Two Test Methods that Purportto Measure the Same Property of a Material2.2 Energy Institute Standard:3IP219 Test Method for Cloud Point of Petroleum Products3. Terminology3.1 Definitions:3.1.1 biodiesel, nfuel comprising mono-alkyl ester
8、s of long-chain fatty acids derived from vegetable oils or animal fats,designated B100.3.1.1.1 DiscussionBiodiesel is typically produced by a reaction of vegetable oil or animal fat with an alcohol such as methanol or ethanol in thepresence of a catalyst to yield mono-esters and glycerin. The fuel t
9、ypically may contain up to 14 different types of fatty acids thatare chemically transformed into fatty acid methyl esters (FAME).3.1.2 biodiesel blend (BXX), nblend of biodiesel fuel with petroleum-based diesel fuel designated BXX, where XX is thevolume percentage (as a whole number without the perc
10、entage sign) of biodiesel.1 This test method is under the jurisdiction ofASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of SubcommitteeD02.07 on Flow Properties.Current edition approved July 1, 2011May 1, 2017. Published August 2011May 2017. D
11、OI:10.1520/D768911.Originally approved in 2011. Last previous edition approvedin 2011 as D7689 11. DOI:10.1520 D7689-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer
12、to the standards Document Summary page on the ASTM website.3 Available from Energy Institute, 61 New Cavendish St., London, WIG 7AR, U.K., http:/www.energyinst.org.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have be
13、en made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official documen
14、t.*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 States13.1.3 cloud point, nin petroleum products and biodiesel fuels, the temperature of a liquid specimen when the smallestob
15、servable cluster of hydrocarbonwax crystals first occurs upon cooling under prescribed conditions.3.1.3.1 DiscussionThe cloud point occurs when the temperature of the specimen is low enough to cause hydrocarbonwax crystals to precipitate. Ina homogeneous liquid, the cloud is always noted first at th
16、e location in the specimen where the specimen temperature is the lowest.The cloud point is the temperature at which the crystals first occur, regardless of their location in the specimen, and not afterextensive crystallization has taken place. The hydrocarbonwax crystals that precipitate at lower te
17、mperatures are typically, but notexcluded to, straight chain hydrocarbons commonly called “wax crystals.”straight-chain hydrocarbons and lipids.3.2 Definitions of Terms Specific to This Standard:3.2.1 D2500/IP219 equivalent cloud point, ntemperature of a specimen, in integers, calculated by applying
18、 a bias androunding the results of this test method to the next lower integer (see 12.2).3.2.1.1 DiscussionThis test method produces results with 0.1C0.1 C resolution. Should the user wish to provide results with a similar format to TestMethod D2500, then this calculation can be performed. Some appa
19、ratus can perform this calculation automatically.3.2.2 mini method, nin cloud point test methods, automatic test procedure using a small sample size, prescribed cooling rate,specimen receptacle, and optical system for detection of crystal formation.3.2.2.1 DiscussionThe prescribed cooling rate is de
20、scribed in 4.1, the specimen receptacle is described in 7.1, and the optical system for detectionof crystal formation is described in 4.1.4. Summary of Test Method4.1 After inserting the test specimen into the automatic apparatus, and initiation of the program, the test specimen is heated, ifnecessa
21、ry, to a starting temperature and then cooled by prescribed rates (11.5 and 11.6). The test specimen is continuouslymonitored for appearance of hydrocarbon crystals with opposing light emitter and optical receiver (Annex A1). When thecrystallization in the specimen is detected by the optical system,
22、 the temperature is recorded to within 0.1C0.1 C resolution. Thespecimen is then heated to facilitate the start of the next test.5. Significance and Use5.1 The cloud point of petroleum products and biodiesel fuels is an index of the lowest temperature of their utility for certainapplications. Wax cr
23、ystals of sufficient quantity can plug filters used in some fuel systems.5.2 Petroleum blending operations require precise measurement of the cloud point.5.3 This test method can determine the temperature of the test specimen at which wax crystals have formed sufficiently to beobserved as a cloud wi
24、th a resolution of 0.1C.0.1 C.5.4 This test method provides results that, when corrected for bias and rounded to the next lower integer (see 12.2), have beenfound equivalent to Test Method D2500.5.5 This test method determines the cloud point in a shorter time period than required by Test Method D25
25、00.6. Apparatus6.1 Automated Apparatus4The apparatus consists of a microprocessorcontrolledmicroprocessor-controlled test specimenchamber that is capable of heating and cooling the test specimen at required rates, optically observing the first appearance ofhydrocarbon wax crystals, and recording the
26、 temperature of the test specimen chamber. A detailed description of the apparatus isprovided in Annex A1.6.2 The apparatus shall be equipped with a thermostatically controlled specimen chamber, digital display, cooling and heatingsystems, optical detection system, and a specimen chamber temperature
27、 measuring device.4 The sole source of supply of the apparatus (ISL Model MPP 5Gs analyzer) known to the committee at this time is ISL, B.P. 70825 14653, Verson, France. If you areaware of alternative suppliers, please provide this information to ASTM International Headquarters. Your comments will r
28、eceive careful consideration at a meeting of theresponsible technical committee,1 which you may attend.D7689 1726.3 The temperature measuring temperature-measuring device in the specimen chamber shall be capable of measuring thetemperature, at minimum, from -6060 C to 60C60 C at a resolution of 0.1C
29、.0.1 C.7. Reagents and Materials7.1 Specimen VialDisposable, clear glass cylinder with closed flat bottom, 1 mL capacity.NOTE 1Standard NWV type vial is suitable.Dimensions:Outer diameter: 8.0 to 8.3 mmWall thickness: 0.75 to 0.85 mmOuter length: 39.25 to 40.25 mm7.2 Specimen Vial Stopper4Disposable
30、, proprietary designed for use in this apparatus.7.3 MicropipetteCapable of delivering 0.50.5 mL 6 0.1 mL of sample. Positive displacement type displacement-typemicropipette with capillary piston is preferred for use. Air-displacement typeAir displacement-type micropipettes are notrecommended for vi
31、scous samples.8. Sampling8.1 Obtain a sample in accordance with Practice D4057 or by Test Method D4177.8.2 At least 1 mL of sample is required for each test.8.3 Samples of very viscous materials may be warmed until they are reasonably fluid before they are tested. However, no sampleshould be heated
32、more than is absolutely necessary.8.4 The sample shall not be heated above 60C.60 C. When the sample is heated above 60C60 C, allow the sample to coolbelow 60C60 C before filtering or inserting into the apparatus.8.5 When moisture is present, remove the moisture by a method,method such as filtration
33、 through dry, lint-free filter paper,paperuntil the oil is perfectly clear, but make such filtration at a temperature at least 14C14 C above the expected cloud point.NOTE 2Moisture will be noticed in the sample as a separate phase or as a haze throughout the entire sample. Generally, a slight haze w
34、ill not interferewith the detection of the wax cloud.9. Preparation of Apparatus9.1 Prepare the instrument for operation in accordance with the manufacturers instructions.10. Calibration and Standardization10.1 Ensure that all of the manufacturers instructions for calibrating, checking, and operatin
35、g the apparatus are followed.10.2 A sample with a well documented well-documented cloud point can be used to verify the performance of the automaticapparatus. Alternatively, a sample that has been extensively tested in a cloud point cross-check program can be used. Suchverification materials can als
36、o be prepared from intracompany cross-checks.11. Procedure11.1 Draw 0.50.5 mL 6 0.1 mL of sample into a micro-pipettemicropipette and transfer the specimen into a new clean, dryspecimen vial. When necessary, heat the sample in a water bath or oven until it is just sufficiently fluid to transfer. Sam
37、ples withan expected cloud point (ECP) above 25C25 C or which appear solid at room temperature can be heated above 45C45 C butshall not be heated above 60C.60 C.11.2 Place a new clean, dry specimen vial stopper on the specimen vial and insert the assembly into the apparatus. Start theoperation of th
38、e apparatus according to the manufacturers instructions.11.3 When the expected cloud point of the specimen is known, program it in the apparatus as ECP (expected cloud point) andstart test sequence. From this point up to and including the termination of the test, recording and reporting of the resul
39、t, theapparatus automatically controls the procedure.11.4 The apparatus shall adjust the specimen chamber to a preselected starting temperature. By default, the preselected startingtemperature is 25C.25 C. Alternatively, the operator can preprogram a defined starting temperature between 2525 C and60
40、C,60 C, if desired. When the expected cloud point is known and programmed in the apparatus, the starting temperature shallbe at least 10C10 C warmer than the expected cloud point. In the event that the preselected starting temperature is programmedlower than 10C10 C above the programmed expected clo
41、ud point, the apparatus shall heat the specimen chamber to a startingtemperature at least 10C10 C above the expected cloud point, but not more than 60C.60 C. (WarningExercise care whenselecting starting temperatures above 40C.40 C. Samples which are fluid at ambient room temperature can also have a
42、lowtemperature flash point. Use higher start temperatures only on samples known to be solid near ambient room temperature.)D7689 17311.5 When the expected cloud point of the specimen is not known, once the starting temperature is reached (see 11.4) cool thespecimen chamber at a rate of 1.51.5 C 6 0.
43、15C/min,0.15 Cmin, while the optical system monitors for the appearance of thecrystals.11.6 When the expected cloud point of the specimen is known,known and programmed into the apparatus, once the startingtemperature (see 11.4) is reached, cool the specimen chamber at a rate of 1010 C 6 1C/min1 Cmin
44、 until 10C10 C warmerthan the programmed expected cloud point, then adjust the cooling rate to 1.51.5 C 6 0.15C/min,0.15 Cmin, while the opticalsystem monitors for appearance of the crystals.11.7 When a cloud point is detected prematurely, during the fast cooling rate, as determined by the apparatus
45、, reheat thespecimen to a higher starting temperature, at least 30C30 C warmer than the temperature of premature detection, and then coolas described in 11.5, while the optical system monitors for appearance of the crystals.11.8 At the detection of the cloud point, record the temperature the specime
46、n attained, to within 0.1C,0.1 C, which is held onthe digital display. Reheat the specimen to the preselected starting temperature.12. Report12.1 Report the temperature recorded in 11.8 to 0.1C0.1 C as the cloud point D7689 (Mini Method).12.2 When specified, correct the temperature recorded in 11.8
47、with the relative bias in accordance with 13.3, round the resultto the next lower integer (a colder temperature), and report as the Test Method D2500 equivalent cloud point per Test MethodD7689.13. Precision and Bias513.1 PrecisionThe precision of this test method as determined by the statistical ex
48、amination of the interlaboratory test resultsis as follows:13.1.1 RepeatabilityThe difference between successive test results, obtained by the same operator using the same apparatusunder constant operating conditions on identical test material, would in the long run, in the normal and correct operat
49、ion of thistest method, exceed Eq 1 only in one case in twenty (see Table 1).0.020630C2X! valid range250 to16C (1)0.020630 C2X! valid range 250 to16 C (1)where:X = cloud point (mini method).13.1.2 ReproducibilityThe difference between two single and independent test results, obtained by different operators workingin different laboratories on identical test material, would in the long run, in normal and correct operation of this test method, exceedEq 2 only in one case in twenty (see
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