ASTM D5985-2002 Standard Test Method for Pour Point of Petroleum Products (Rotational Method)《石油产品倾点的标准测试方法(旋转法)》.pdf

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1、Designation: D 5985 02An American National StandardStandard Test Method forPour Point of Petroleum Products (Rotational Method)1This standard is issued under the fixed designation D 5985; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revis

2、ion, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.INTRODUCTIONThis test method covers an alternative procedure for the determination of pour point of petroleumpro

3、ducts using an automatic apparatus.1. Scope*1.1 This test method covers the determination of pour pointof petroleum products by an automatic instrument that con-tinuously rotates the test specimen against a suspended detec-tion device during cooling of the test specimen.1.2 This test method is desig

4、ned to cover the range oftemperatures from 57 to + 51C; however, the range oftemperatures included in the 1992 interlaboratory programonly covered the temperature range of 39 to + 6C (see 13.4).1.3 This test method determines the no-flow point of petro-leum products by detection of the crystal struc

5、ture or viscosityincrease, or both, in the sample that is sufficient to impede flowof the specimen.1.4 This test method is not intended for use with crude oils.NOTE 1The applicability of this test method on residual fuel sampleshas not been verified. For further information on applicability, refer t

6、o13.4.1.5 The values stated in inch-pound units are to be regardedas the standard. The values given in parentheses are forinformation only.1.6 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

7、 establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:D97 Test Method for Pour Point of Petroleum Products2D 4057 Practice for Manual Sampling of Petroleum andPetroleum Products3D 4177 Pra

8、ctice for Automatic Sampling of Petroleum andPetroleum Products32.2 IP Standards:IP15 Test Method for Pour Point of Petroleum Products43. Terminology3.1 Definitions:3.1.1 pour point, nin petroleum products, the lowesttemperature at which movement of the test specimen isobserved under prescribed cond

9、itions of test.3.2 Definitions of Terms Specific to This Standard:3.2.1 no-flow point, nin petroleum products, the tempera-ture of the test specimen at which a wax crystal structure orviscosity increase, or both, impedes movement of the surfaceof the test specimen under the conditions of the test.3.

10、2.2 DiscussionThe no-flow point occurs when, uponcooling, the formation of wax crystal structures or viscosityincrease, or both, have progressed to the point where theapplied observation device no longer detects movement underthe conditions of the test. The preceding observation tempera-ture, at whi

11、ch flow of the test specimen is last observed, is thepour point.3.2.3 pour point at 3C testing intervals, nin petroleumproducts, the temperature calculated by rounding the no-flowpoint of the test specimen to the next higher integer which is amultiple of 3C.3.2.4 DiscussionThe no-flow point can be m

12、easured witha resolution of 0.1C in this test method. In Test Method D97observations for no-flow are in 3C intervals and when resultswith a similar format to Test Method D97are required, thiscalculation shall be performed. Some apparatus can performthis calculation automatically.3.2.5 rotational, ni

13、n this standard, the technique of turn-ing the test specimen jar in an upright position upon a turntablewith a stationary positioned, temperature sensor containingpendulum, inserted into the test specimen.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubr

14、icants and is the direct responsibility of SubcommitteeD02.07 on Flow Properties.Current edition approved Jan. 10, 2002. Published March 2002. Originallypublished as D 5985 96. Last previous edition D 5985 96e1.2Annual Book of ASTM Standards, Vol 05.01.3Annual Book of ASTM Standards, Vol 05.02.4Avai

15、lable from Institute of Petroleum, 61 New Cavendish St., London, EnglandW1M 8AR.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.6 DiscussionUpon cooling of the tes

16、t specimen, theresultant crystal formation or viscosity increase in the speci-men exerts force upon the pendulum, offsetting the stationaryposition and causing detection of the no-flow point.4. Summary of Test Method4.1 After inserting the test specimen into the automatic pourpoint apparatus, and in

17、itiation of the program, the test speci-men is heated and then cooled by maintaining a constanttemperature differential between the cooling block and thesample. The test specimen is continuously tested for flowcharacteristics by rotating the test specimen cup at approxi-mately 0.1 rpm against a stat

18、ionary, counter-balanced, sphere-shaped pendulum. The temperature of the test specimen atwhich a crystal structure or a viscosity increase, or both, withinthe test specimen causes the displacement of the pendulum isrecorded with a resolution of 0.1C. The test specimen is thenheated to the original s

19、tarting temperature.5. Significance and Use5.1 The pour point of a petroleum product is an index of thelowest temperature of its utility for certain applications. Flowcharacteristics, such as pour point, can be critical for thecorrect operation of lubricating systems, fuel systems, andpipeline opera

20、tions.5.2 Petroleum blending operations require precise measure-ment of the pour point.5.3 This test method can determine the temperature of thetest specimen with a resolution of 0.1C at which eithercrystals have formed or viscosity increases sufficiently toimpede movement of the petroleum product.5

21、.4 This test method yields a pour point in a format similarto Test Method D97/IP15 when the 3C interval results arereported.NOTE 2Since some users may wish to report their results in a formatsimilar to Test Method D97(in 3C intervals) the precisions were derivedfor the temperatures rounded to the 3C

22、 intervals. For statements on biasrelative to Test Method D97, see 13.3.5.5 This test method has better repeatability and comparablereproducibility relative to Test Method D97as measured in the1992 interlaboratory program.56. Apparatus6.1 Automatic Apparatus6The automatic pour point appa-ratus descr

23、ibed in the Annex A1 consists of a microprocessorcontrolled measuring unit that is capable of heating, cooling,rotating, and recording the temperature of the test specimen.The apparatus shall be equipped with a digital display, cooling/heating block assembly, turntable, test specimen cup andmeasurin

24、g head containing a counter-balanced pendulum andtemperature measuring device.6.2 Test Specimen CupThe test specimen cup is a flatbottom aluminum cup with the dimensions inA1.2. To indicatethe required fill level, the inside of the test cup is scribed at aheight of 36 6 0.2 mm above the inside botto

25、m. The outsidebottom of the test cup has two indentions to facilitate therotation of the test cup.6.3 Circulating BathRefrigeration unit equipped with acirculating pump capable of maintaining a temperature at least20C colder than the lowest expected pour point to bemeasured.7. Reagents and Material7

26、.1 Methyl Alcohol, anhydrous, for use as cooling mediumin circulating bath.7.2 Cleaning Solvents, suitable for cleaning and drying thespecimen cup and pendulum, such as petroleum naptha andacetone. (WarningFlammable. Liquid causes eye burns.Vapor harmful. May be fatal or cause blindness if swallowed

27、 orinhaled.)8. Sampling8.1 Obtain a sample in accordance with Practices D 4057 orby D 4177.8.2 Samples of very viscous materials can be warmed untilthey are reasonably fluid before they are transferred; however,no sample shall be heated more than is absolutely necessary.The sample shall not be heate

28、d and transferred into the testspecimen cup unless its temperature is 70C or lower.NOTE 3In the event the sample has been heated above this tempera-ture, allow the sample to cool until its temperature is at least 70C beforetransferring.9. Preparation of Apparatus9.1 Prepare the instrument for operat

29、ion in accordance withthe manufacturers instructions.9.2 Clean and dry the test specimen cup and the coolingwell using suitable solvents as prescribed by the apparatusmanufacturer.9.3 Prepare the refrigerated circulating bath for operation inaccordance with the manufacturers instructions and allow i

30、t toattain a temperature at least 20C lower than the expected pourpoint of the sample.10. Calibration and Standardization10.1 Ensure that all of the manufacturers instructions forcalibrating, checking, and operating the apparatus are fol-lowed.10.2 Adjust the position of the measuring pendulum, when

31、necessary, according to the manufacturers instructions.10.3 A sample with a well documented pour point can beused to verify performance of the apparatus. Alternatively, asample which has been extensively tested in a pour pointinterlaboratory study can be used.11. Procedure11.1 Transfer the specimen

32、into the test specimen cup to thescribed mark. When necessary, heat the sample in a water bathor oven until it is just sufficiently fluid to transfer into the test5The results of the 1992 Interlaboratory Cooperative Test Program are availablefrom ASTM International Headquarters in the form of a rese

33、arch report. RequestRR:D02-1312.6The following instrument has been found suitable for use in this test method:Herzog Model MC 850 available from Walter Herzog, Lauda, Germany.D5985022specimen cup. Samples with an expected pour point above36C or which appear solid at room temperature can be heatedabo

34、ve 45C but shall not be heated above 70C (see Note 3).NOTE 4Residual fuels have been known to be sensitive to thermalhistory. In the case where a residual fuel sample is tested, refer to TestMethod D97for sample treatment.11.2 Make sure that the cooling well is free of moisture. Ifit is not, remove

35、all moisture by wiping with a dry cloth. Insertthe test specimen cup into the cooling well. Bring the measur-ing head into position over the test specimen cup and lower itinto the test specimen.11.3 Start the test program following the manufacturersinstructions.11.4 When the expected pour point is k

36、nown to be higherthan 33C, preselect a starting temperature which is at least9C higher than the expected pour point, but at least 45C. Thehighest starting temperature that can be programmed is 70C.11.5 When the expected pour point is known to be at orbelow 33C, the test duration can be shortened by

37、preselect-ing a starting temperature which is at least 9C higher than theexpected pour point. The lowest starting temperature that canbe programmed is 20C.11.6 When the expected pour point is not known and thesample appears to be liquid, preselect a starting temperature of45C. The apparatus automati

38、cally heats the test specimen toapproximately 45C when a starting temperature is not se-lected. When the expected pour point is not known and thesample needs to be heated before transferring into the testspecimen cup, preselect a starting temperature of 70C.11.7 Initially, the test specimen is heate

39、d to approximately45C, or to the starting temperature preselected by the operatorbetween 20 and 70C. The test specimen cup is continuouslyrotated at approximately 0.1 rpm and flow of the cooling fluidfrom the circulating bath is regulated to maintain the coolingblock at a temperature approximately 8

40、C lower than the testspecimen temperature. The test specimen temperature is con-tinuously displayed. At the detection of the last flow point, thetemperature the test specimen attained is held on the digitaldisplay until reset by the operator. The test specimen is thenheated to approximately 45C, or

41、to the preselected tempera-ture.11.8 The test specimen temperature rounded up to the next3C integer is also displayed.12. Report12.1 Report the temperature recorded in 11.7, with resolu-tion of 0.1C, as the no-flow point in accordance with TestMethod D 5985 (rotational method).12.2 Report the temper

42、ature recorded in 11.8 as the pourpoint at 3C testing intervals in accordance with Test MethodD 5985.13. Precision and Bias13.1 PrecisionThe precision of this test method as deter-mined by the statistical examination of the interlaboratory testresults is as follows:613.1.1 Pour Point at 3C Testing I

43、ntervals (RotationalMethod):13.1.1.1 RepeatabilityThe difference between successivetest results, obtained by the same operator using the sameapparatus under constant operating conditions on identical testmaterial, would in the long run, in the normal and correctoperation of this test method, exceed

44、the following only in onecase in twenty.2.3C13.1.1.2 ReproducibilityThe difference between twosingle and independent test results, obtained by differentoperators working in different laboratories on identical testmaterial, would in the long run, in normal and correct operationof this test method, ex

45、ceed the following only in one case intwenty.8.7C13.1.2 No-Flow PointRepeatabilityThe difference be-tween successive test results, obtained by the same operatorusing the same apparatus under constant operating conditionson identical test material, would in the long run, in the normaland correct oper

46、ation of this test method, exceed the followingonly in one case in twenty.1.18C13.2 BiasSince there is no accepted reference materialsuitable for determining the bias for the procedure in this testmethod, bias has not been determined.13.3 Relative Bias:13.3.1 Pour points at 3C testing intervals were

47、 compared tothe results from Test Method D97. Relative bias5amongcertain samples was observed; however, the observed bias doesnot appear to be of a systematic nature. Biases relative to TestMethod D97/IP15 may conceivably occur for sample types notincluded in the laboratory test program.NOTE 5Large

48、differences in results were observed between methodsfor one sample in the Interlaboratory Test Study. The sample was ahigh-sulfur winter diesel. When cooled during the performance of a testmethod, this sample formed thin, but very large crystals, that could bedescribed as large plates. These crystal

49、s formed wherever sample-glasscontact was made as well as covered the top surface of the sample. Theentire sample, except for this all encasing thin skin of crystals, remainedliquid with apparent low viscosity. When this occurred and the sample washandled gently, the sample did not pour, but with rougher handling, thecrust broke and the sample poured readily. Users of this method areadvised to be alert for differences in results between test methods whenthis behavior is observed in the sample being tested.13.4