ASTM D5949-2008 374 Standard Test Method for Pour Point of Petroleum Products (Automatic Pressure Pulsing Method).pdf

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1、Designation: D 5949 08An American National StandardStandard Test Method forPour Point of Petroleum Products (Automatic PressurePulsing Method)1This standard is issued under the fixed designation D 5949; the number immediately following the designation indicates the year oforiginal adoption or, in th

2、e case of revision, the year 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.INTRODUCTIONThis test method covers an alternative procedure for the determination of pour point o

3、f petroleumproducts using an automatic apparatus.1. Scope*1.1 This test method covers the determination of pour pointof petroleum products by an automatic instrument that appliesa controlled burst of nitrogen gas onto the specimen surfacewhile the specimen is being cooled and detects movement ofthe

4、surface of the test specimen with an optical device.1.2 This test method is designed to cover the range oftemperatures from 57 to +51C. However, the range of tem-peratures included in the 1992 interlaboratory test programonly covered the temperature range from 39 to +6C and therange of temperatures

5、included in the 1998 interlaboratory testprogram was from 51 to 11C. (see 13.4).1.3 Test results from this test method can be determined at1 or 3C testing intervals.1.4 This test method is not intended for use with crude oils.NOTE 1The applicability of this test method or residual fuel sampleshas no

6、t been verified. For further information on applicability, refer to13.4.1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use

7、. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D97 Test Method for Pour Point of Petroleum ProductsD 4057 Practice for Manu

8、al Sampling of Petroleum andPetroleum ProductsD 4177 Practice for Automatic Sampling of Petroleum andPetroleum Products2.2 Energy Institute Standard:IP 15 Test Method for Pour Point of Petroleum Products33. Terminology3.1 Definitions:3.1.1 pour point, nin petroleum products, the lowesttemperature at

9、 which movement of the test specimen isobserved under the prescribed conditions of the 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 mo

10、vement 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 crystal structures or viscosityincrease, or both, has progressed to the point where the appliedobservation device no longer detects movement u

11、nder theconditions of the test. The preceding observation temperature,at which flow of the test specimen is last observed, is the pourpoint.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.07 on

12、Flow Properties.Current edition approved Dec. 1, 2008. Published January 2009. Originallyapproved in 1996. Last previous edition approved in 2001 as D 5949011.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of

13、ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from Energy Institute, 61 New Cavendish St., London, WIG 7AR,U.K., http:/www.energyinst.org.uk.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International,

14、 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.2 pulse, na controlled burst of nitrogen gas of a fixedpressure and flow rate sufficient to cause movement on thesurface of the test specimen without fracturing the waxstructure which may be formed in the specim

15、en.3.2.3 Peltier device, na solid-state thermoelectric deviceconstructed with dissimilar semiconductor materials, config-ured in such a way that it will transport heat to or away froma test specimen dependent on the direction of electric currentapplied to the device.4. Summary of Test Method4.1 Afte

16、r inserting the test specimen into the automatic pourpoint apparatus, and initiation of the test program, the testspecimen is heated and then cooled by a Peltier device at a rateof 1.5 6 0.1C/min. At temperature intervals of 1 or 3C,depending on the selection made by the user, a moving force inthe f

17、orm of a pressurized pulse of nitrogen gas is imparted ontothe surface of the specimen. Multiple optical detectors are usedin conjunction with a light source to monitor movement of thesurface of the specimen. The lowest temperature at whichmovement of the specimen surface is observed upon applica-ti

18、on of a pulse of nitrogen gas is recorded as the pour point,Test Method D 5949.5. 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

19、 of lubricating oil systems, fuel systems, and pipelineoperations.5.2 Petroleum blending operations require precise measure-ment of the pour point.5.3 In most cases, this test method does not require the useof mechanical refrigeration apparatus (see 7.1).5.4 This test method yields a pour point in a

20、 format similarto Test Method D97/IP 15 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 derivedfrom the temperatures rounded to the 3 intervals. For statements on biasrelative

21、to Test Method D97, see 13.3.5.5 Test results from this test method can be determined ateither 1 or 3C intervals.5.6 This test method has better repeatability and reproduc-ibility relative to Test Method D97/IP 15 as measured in the1992 and 1998 interlaboratory test programs.46. Apparatus6.1 Automat

22、ic Apparatus5The automatic pour point appa-ratus described in this test method consists of a microprocessorcontrolled test chamber that is capable of heating and coolingthe test specimen, providing a controlled pulse of nitrogen gasonto the specimen surface, optically detecting the specimensurface m

23、ovement, and recording the temperature of thespecimen as described in detail in Annex A1. It is specificallydesigned to detect the lowest temperature at which movementof the surface of the specimen is observed upon application ofthe pulse.6.2 The apparatus shall be equipped with a specimen cup, anar

24、ray of optical detectors, light source, pressure pulsing unit,digital display, Peltier device, and a specimen temperaturemeasuring device.6.3 The pressure pulsing unit consists of a stainless steeltubing, 250 6 2 mm long and 1.1 6 0.1 mm inside diameter.This tubing is connected to a constant pressur

25、e source at oneend, which serves as an inlet. The other end of the tubing,which serves as the outlet, is bent and positioned such that it ispointing to the center of the specimen at an acute angle. Thedistance between the outlet and the center of the specimen is 86 2 mm.6.4 The Peltier device shall

26、be capable of heating or coolingthe test specimen at a rate of 1.5 6 0.1C/min.6.5 The temperature measuring device in the specimen cupshall be capable of measuring the temperature of the testspecimen from 80 to +70C at a resolution of 0.1C.6.6 The apparatus shall be equipped with fittings to permitt

27、he circulation of water or other liquid cooling media to removeheat generated by the Peltier device and other electroniccomponents of the apparatus.6.7 The apparatus shall be equipped with fittings to permitthe delivery of nitrogen gas to the pressure pulsing unit.7. Reagents and Materials7.1 Coolan

28、tTap water or other liquid heat exchangemedium sufficient to remove heat generated by the Peltierdevice and other electronic components from the apparatus. Toachieve specimen cooling to 60C, supply circulation ofliquid cooling medium at +25C or lower to the apparatus.4The results of this interlabora

29、tory test program are available from ASTMInternational Headquarters in the form of a research report. Request RR:D02-1312for the 1992 program and RR:D021499 for the 1998 program.5The following instrument has been found suitable for use in this test method:Phase Technology Pour Point Analyzer model s

30、eries 30, 50, 70, 70V and 70X;available from Phase Technology, 11168 Hammersmith Gate, Richmond, B.C.CanadaV7A5H8. In the 1998 research report, the 70Vwas referred to as the currentmodel; whereas models 30, 50, and 70 were referred to as pre-1998 models. Thevarious model series mentioned above are d

31、ifferentiated by their cooling capacitiesand user interfaces; however, all of them are capable of covering the entiretemperature range specified in the scope.This pour point analyzer is covered by a patent. Interested parties are invited tosubmit information regarding the identification of an altern

32、ative to this patented itemto the ASTM International Headquarters. Your comments will receive carefulconsideration at a meeting of the responsible technical committee which you mayattend.D5949082Obtain cooling performance data from the apparatus manufac-turer if lower specimen temperatures are desir

33、ed or if the tapwater temperature is higher than 25C.7.2 Dry Nitrogen GasNitrogen gas with a dew pointbelow the lowest temperature attained by the specimen(WarningCompressed gas.) (WarningInert gas can be anasphyxiant when inhaled.)7.3 Precision Volume-Dispensing Device, capable of dis-pensing 0.150

34、 6 0.005 mL of sample.7.4 Cotton Swab, plastic shaft cotton swabs to clean thesample cup.8. Sampling8.1 Obtain a sample in accordance with Practice D 4057 orby Practice D 4177.8.2 Samples of very viscous materials may be warmed untilthey are reasonably fluid before they are transferred; however,no s

35、ample shall be heated more than is absolutely necessary.The sample shall not be heated 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 70

36、C beforetransferring.9. Preparation of Apparatus9.1 Install the analyzer for operation in accordance with themanufacturers instructions.9.2 Turn on the liquid cooling medium and ensure itstemperature is appropriate for the specimen being tested inaccordance with manufacturers instructions (see 7.1).

37、9.3 Turn on the nitrogen gas and ensure that it is regulatedto the appropriate pressure in accordance with the manufactur-ers instructions.9.4 Turn on the main power switch of the analyzer.10. Calibration and Standardization10.1 Ensure that all of the manufacturers instructions forcalibrating, check

38、ing, and operating the apparatus are fol-lowed.10.2 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 Open the test chamber lid and

39、clean the specimen cupinside the test chamber with a cotton swab.11.2 Deliver 0.150 6 0.005 mL of specimen into thespecimen cup. Pipettes, syringes, or precision positive-displacement devices are suitable for use in delivering thespecimen. Samples with an expected pour point above 36C orwhich appear

40、 solid at room temperature can be heated above45C, but shall not be heated above 70C (see Note 4). Cleanthe specimen out of the cup by using a cotton swab. The cupshall be cleaned to the point where no visible droplets ofspecimen remain in the cup.11.3 Repeat step 11.2.11.4 Carefully measure 0.150 6

41、 0.005 mL of the specimeninto the specimen cup.11.5 Close and lock the test chamber lid.11.6 Follow the manufacturers instructions for preheatingthe specimen.11.7 Select the desired pour point testing interval: 1 or 3C.11.8 Start the test program following the manufacturersinstructions. The specimen

42、 is first heated as specified in 11.6.Itis then cooled by the Peltier device at a rate of 1.5 60.1C/min. The apparatus will apply a pulse of pressurizednitrogen gas onto the specimen surface every 1 or 3C drop intemperature depending on the testing interval specified in 11.7.The specimen is illumina

43、ted by the light source, and themovement of the specimen surface upon application of a pulseis monitored by an array of optical detectors. The test willcontinue until application of a pulse of nitrogen gas causes noobservable movement on the specimen surface. This is theno-flow point of the specimen

44、. The lowest temperature atwhich movement of the specimen surface is observed uponapplication of the pulse of nitrogen gas is recorded as the pourpoint. The pour point value shall be displayed as an integertemperature in multiples of 1 or 3C depending on the selectedtesting interval.11.9 Unlock and

45、open the test chamber lid and clean thespecimen out of the specimen cup with a cotton swab.12. Report12.1 Report the temperature recorded in 11.8 together withthe testing interval as pour point Test Method D 5949.13. Precision and Bias13.1 PrecisionThe precision of this test method as deter-mined by

46、 the statistical examination of the interlaboratory testresults4is as follows:13.1.1 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 a

47、nd correctoperation of this test method, exceed the following values onlyin one case in twenty.1C Test Interval 3C Test IntervalModel 70V51.6C 2.2CModels 30, 50, 7052.9C 4.1C13.1.2 ReproducibilityThe difference between two singleand independent test results, obtained by different operatorsworking in

48、 different laboratories on identical test material,would in the long run, in normal and correct operation of thistest method, exceed the following values only in one case intwenty.1C Test Interval 3C Test IntervalModel 70V53.2C 3.8CModels 30, 50, 7056.2C 6.3C13.2 BiasSince there is no accepted refer

49、ence 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 compared tothe results from Test Method D97. Relative bias4amongcertain samples was observed; however, the observed bias doesnot appear to be of a systematic nature. Biases relative to TestD5949083Method D97/IP 15 may conceivably occur for sample typesnot included in the 1998 interlaboratory test program.NOTE 4Large differences in resul