ASTM D5950-2002 Standard Test Method for Pour Point of Petroleum Products (Automatic Tilt Method)《石油产品倾点的标准测试方法(自动倾斜法)》.pdf

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1、Designation: D 5950 02An American National StandardStandard Test Method forPour Point of Petroleum Products (Automatic Tilt Method)1This standard is issued under the fixed designation D 5950; the number immediately following the designation indicates the year oforiginal adoption or, in the case of r

2、evision, 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 petroleu

3、mproducts using an automatic apparatus.1. Scope*1.1 This test method covers the determination of pour pointof petroleum products by an automatic instrument that tilts thetest jar during cooling and detects movement of the surface ofthe test specimen with an optical device.1.2 This test method is des

4、igned to cover the range oftemperatures from 57 to +51C; however, the range oftemperatures included in the 1992 interlaboratory test programonly covered the temperature range from 39 to +6C, and therange of temperatures included in the 1998 interlaboratory testprogram was 51 to 11C. (see 13.4).1.3 T

5、est results from this test method can be determined at1 or 3C intervals.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 to13.4.1.5 The values stated

6、 in SI units are regarded as standard.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 establish appro-priate safety and health practices and determine the applica-bility of regulatory li

7、mitations 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 Practice for Automatic Sampling of Petroleum andPetroleum Products32.2 IP Standard:IP15 Test Method for

8、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 the prescribed conditions of this test method.3.2 Definitions of Terms Specific to This Standard:3.2.1 no-flow point,

9、 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.3.2.1.1 DiscussionThe no-flow point occurs when, uponcooling, the formation of wax cryst

10、al structures or the viscosityincrease, or both, has progressed to the point where the appliedobservation device no longer detects movement under theconditions of the test. The preceding observation temperature,at which flow of the test specimen is last observed, is the pourpoint.3.2.2 tiltingtechni

11、que of movement where the test jar in avertical position is moved towards a horizontal position toinduce specimen movement.3.2.2.1 DiscussionWhen the test jar is tilted and held in ahorizontal position for 5 s without detection of specimenmovement, this is the no-flow point and the test is complete.

12、4. Summary of Test Method4.1 After preliminary heating, the test specimen is insertedinto the automatic pour point apparatus. After starting theprogram, the specimen is cooled according to the coolingprofile listed in Table 1 and examined at either 1 or 3Cintervals. The lowest temperature at which m

13、ovement ofspecimen is detected, by the automatic equipment, is displayedas the pour point.NOTE 2If the automatic pour apparatuss preheat option is utilized,1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of Subcom

14、mitteeD02.07 on Flow Properties.Current edition approved Jan. 10, 2002. Published March 2002. Originallypublished as D 5950 96. Last previous edition D 5950 96.2Annual Book of ASTM Standards, Vol 05.01.3Annual Book of ASTM Standards, Vol 05.02.4Available from Institute of Petroleum, 61 New Cavendish

15、 St., London, EnglandWiM 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.place the test specimen into the apparatus. After starting the program, theapparatus will

16、automatically carry out the preliminary heating.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, like pour point, can be critical for the correctoperation of lubricating oil systems, fu

17、el systems, and pipelineoperations.5.2 Petroleum blending operations require precise measure-ment of the pour point.5.3 This test method can determine the pour point of the testspecimen with a resolution of 1.0C.5.4 Test results from this test method can be determined ateither 1 or 3C intervals.5.5

18、This test method yields a pour point in a format similarto Test Method D97/IP15 when the 3C interval results arereported.NOTE 3Since 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 in

19、tervals. For statements on biasrelative to Test Method D97, see 13.3.5.6 This test method has better repeatability and reproduc-ibility relative to Test Method D97/IP15 as measured in the1998 interlaboratory test program.56. Apparatus6.1 Optical Automatic Pour Point Apparatus6The auto-matic pour poi

20、nt apparatus described in this test methodconsists of a microprocessor controller that is capable ofcontrolling one or more independent test cells. The apparatusshall include provisions for independently controlling thetemperature of each cell according to the specified coolingprofile, monitoring co

21、ntinuously the specimen temperature,and detecting any movement of the specimen during tilting (seeFig. 1). The instrument shall be operated according to themanufacturers instructions.6.2 Temperature Probe, IEC 751 Class A: D T=6(0.15 + 0.002 |T|), capable of measurement from +70 down to80C. The temp

22、erature probe shall be in the center of the testjar and the top of the platinum tip immersed 3 mm below thesurface of the oil.6.3 Test Jar, clear cylindrical glass, flat bottom, 34 60.1-mm outside diameter, 31 6 0.3-mm inside diameter, 120 60.5-mm height, thickness of the bottom 2.4-mm maximum. Itsh

23、all be marked with a line to indicate the sample height 54 60.5-mm above the inside bottom.6.4 Jacket, brass, cylindrical, flat bottom, 113 60.2-mm indepth, 45 +0, 0.1-mm inside diameter. It shall be cooledaccording to the cooling profile specified.6.5 Cooling Circulating Bath, equipped with a circu

24、latingpump and capable of maintaining a temperature at least 10Cbelow the last required jacket temperature level (see Table 1and Fig. 2).5The results of this interlaboratory test program are available from ASTMInternational Headquarters in the form of a research report. Request RR:D02-1312for the 19

25、92 program and RR:D02-1499 for the 1998 program.6The following apparatus have been found suitable for use in this test method:ISL models CPP 976 and CPP 972; available from ISL SA, BP 40, 14790 Verson,France.TABLE 1 Jacket and Specimen Temperature Cooling ProfileSpecimen Temperature, C Jacket Temper

26、ature, C+27=ST+9 06 0.5+9=ST6 186 0.56=ST24 336 0.524=ST42 516 0.542=ST58 696 0.5FIG. 1 Optical Detection SystemD59500226.6 Cork Disk,66 0.2 mm thick to fit loosely inside thejacket. Felt may be used but special attention must be paid toavoid moisture in the felt disk. The felt disk must be driedbef

27、ore each test.6.7 Cork Ring, to fit snugly around the outside of the test jarand loosely inside the test cell. Its purpose is to prevent the testjar from touching the cooling jacket.7. Reagents and Materials7.1 Methyl Alcohol, anhydrous, for use as cooling mediumin circulating bath.7.2 Cleaning Solv

28、ents, suitable for cleaning and drying thetest jar and test head, such as petroleum naphtha and hexane.(Warning: Flammable. Liquid causes eye burns. Vapor harm-ful. May be fatal or cause blindness if swallowed or inhaled.)8. Sampling8.1 Obtain a sample in accordance with Practice D 4057 orPractice D

29、 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 heated and transferred into the testspecimen jar unless its temperature is 70C or lower.NO

30、TE 4In 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 operation in accordance withthe manufacturers instructions.9.2 Clean and dry the test head

31、and test jar using suitablesolvents as prescribed by the manufacturer.9.3 Adjust the set-point of the recirculating cooler to theappropriate temperature to cool the jackets to the requiredtemperatures (see Table 1).NOTE 5For most applications the recirculating cooler will be set at itslowest operati

32、ng temperature.10. Calibration and Standardization10.1 Ensure that all of the manufacturers instructions forcalibrating, checking, and operating the apparatus are fol-lowed.10.1.1 A test head simulator, Part No. V02306, is used tocalibrate the equipment. The test head simulator uses precisionresisto

33、rs in place of the PT 100 temperature probe to calibratethe jacket and specimen temperature electronics. Follow themanufacturers calibration instructions.10.2 A sample with a well documented pour point can beused to verify performance of the apparatus. Alternatively, asample which has been extensive

34、ly tested in a pour pointinterlaboratory study can be used.11. Procedure11.1 Pour the sample into the test specimen jar to the scribedmark. When necessary, heat the sample in a water bath or ovenuntil it is just sufficiently fluid to pour the sample into the testspecimen jar. Samples with an expecte

35、d pour point above 36Cor samples which appear solid at room temperature can beheated above 45C, but should not be heated above 70C (seeNote 4).11.2 Subject the test specimen to the following preliminarytreatment or use the instruments automatic preheat option.NOTE 6Residual fuels have been known to

36、be sensitive to thermalhistory. In the case where a residual fuel sample is tested, refer to TestMethod D97for sample treatment.11.2.1 When the expected pour point (EP) is known to be#33C, heat the test specimen to 45C in a bath or ovenmaintained at 48C.11.2.2 When the expected pour point (EP) is kn

37、own to be33C, heat the test specimen to EP + 9C, or at least to 45Cbut no higher than 70C (see Note 4).11.3 Place a cork disk at the bottom of the jacket in therequired cell and fit a cork ring to the test jar. The cork ringshould be 25 6 3 mm above the bottom of the test jar.11.4 Place the test jar

38、 in the selected test cell. Attach thedetector head according to the manufacturers instructions.11.5 Select the desired testing interval (1 or 3C).11.6 Enter the expected pour point (EP). If 3C testingintervals are chosen (11.5) you must enter an expected pourpoint that is a multiple of 3C.11.7 Star

39、t the test in accordance with the manufacturersinstructions.11.8 At this point, the instrument shall monitor the testspecimen with the optical detector, adjusting the jacket tem-perature to the first temperature level (according to Table 1)FIG. 2 Description of Pour Point Cell and Cooling Circulatin

40、g BathD5950023and measuring the specimen temperature. The instrument shallautomatically change the jacket temperature in accordancewith the specimen temperature (according to Table 1). The timeto move the jacket temperature from one level to the next lowerlevel shall not exceed 90 s. The instrument

41、shall start tilting thespecimen (without removing it from the jacket) in the pre-scribed manner when the temperature of the test specimen is at9C higher than the expected pour point. If the specimen flowsduring the tilting movement, the no-flow point is not reachedand the jacket returns to the waiti

42、ng vertical position for thenext test. The test will continue until the jacket is in a completehorizontal position and the detector does not detect anymovement of the specimen for 5 s. This temperature, theno-flow point, plus 1 or 3C (depending on the test intervalselected) is the pour point of the

43、oil (see Fig. 1). When the pourpoint is determined, the instrument shall display the pour pointresult and start to reheat the test specimen.11.9 If the instrument detects the no-flow point on the firsttilting cycle (EP + 9C), disregard the result and start with 11.1using a higher expected pour point

44、.11.10 Record the result as the pour point without anycorrection.NOTE 7Residual 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.12. Report12.1 Report the temperature recorded in 11.10 together wi

45、ththe testing interval as pour point in accordance with TestMethod D 5950.13. Precision and Bias13.1 PrecisionThe precision of this test method as deter-mined by the statistical examination of the interlaboratory testresults is as follows:13.1.1 Pour Point at 3C Testing Intervals13.1.1.1 Repeatabili

46、tyThe 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 the following, only in onecase in twenty.3.9C13.

47、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, exceed the following, only in one case intwenty.6

48、.1C13.1.2 Pour Point at 1C Testing Intervals13.1.2.1 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

49、 method, exceed the following, only in onecase in twenty.2.7C13.1.2.2 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, exceed the following, only in one case intwenty.4.5C13.2 BiasSince there is no accepted reference materialsuitable for determining the bias for the procedure in this testmethod, bias has no