1、Designation: D7154 05 (Reapproved 2010)IP 528Standard Test Method forFreezing Point of Aviation Fuels (Automatic Fiber OpticalMethod)1This standard is issued under the fixed designation D7154; the number immediately following the designation indicates the year oforiginal adoption or, in the case of
2、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 is nearly identical to Test Method D5901. The difference in this test method is
3、 theversion of software (version V.22) that is utilized in the apparatus. This version of software is intendedto better identify samples that are contaminated. Since the algorithm in this version of software isdifferent than previous versions utilized in this apparatus, the subcommittee determined t
4、o publish aseparate test method with a different standard designation.1. Scope1.1 This test method covers the determination of the tem-perature below which solid hydrocarbon crystals may form inaviation turbine fuels.NOTE 1This test method describes an alternative procedure andautomatic apparatus wh
5、ich closely mimics the apparatus and proceduredescribed in Test Method D2386.1.2 The measuring range of the apparatus is from -70 to0C, however the precision statements were derived only fromsamples with freezing point temperatures from -60 to -42C.NOTE 2Typical aviation fuel has freezing point temp
6、eratures in the-60 to -40C range.1.3 Some results from this test method (14% of samplesincluded in the 2003 round robin2) incorrectly identifiedsample contamination where no contaminants were present inthe samples (see research report2for further information).1.4 The values stated in SI units are to
7、 be regarded asstandard. No other units of measurement are included in thisstandard.1.5 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
8、 determine the applica-bility of regulatory limitations prior to use. For specific hazardstatements, see Section 7.2. Referenced Documents2.1 ASTM Standards:3D2386 Test Method for Freezing Point of Aviation FuelsD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4177 Practice for
9、Automatic Sampling of Petroleum andPetroleum ProductsD5901 Test Method for Freezing Point of Aviation Fuels(Automated Optical Method)D6708 Practice for StatisticalAssessment and Improvementof Expected Agreement Between Two Test Methods thatPurport to Measure the Same Property of a MaterialE1 Specifi
10、cation for ASTM Liquid-in-Glass Thermometers2.2 Energy Institute Standard:IP 16 Determination Freezing Point of Aviation Fuels3. Terminology3.1 Definitions:3.1.1 freezing point, nin aviation fuels, the fuel tempera-ture at which solid hydrocarbon crystals, formed on cooling,disappear when the temper
11、ature of the fuel is allowed to riseunder specified conditions of test.3.2 Definitions of Terms Specific to This Standard:3.2.1 automatic fiber optical method, nthe robotic auto-mation of a manual procedure and apparatus and use of fiber1This test method is under the jurisdiction of ASTM CommitteeD0
12、2 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.07 on Flow Properties.Current edition approved May 1, 2010. Published May 2010. Originallyapproved in 2005. Last previous edition approved in 2005 as D715405. DOI:10.1520/D7154-05R10.2Supporting data (2003 Inte
13、rlaboratory Cooperative Test Program) have beenfiled at ASTM International Headquarters and may be obtained by requestingResearch Report RR:D02-1572.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStanda
14、rds volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.optics to transmit crystal detection signals to and from thespecimen test chamber.4. Summary of T
15、est Method4.1 After insertion of 25 mL of the test specimen into a testchamber, the test specimen is cooled while being continuouslystirred and monitored by a fiber optical system. The tempera-ture of the specimen is measured with an electronic tempera-ture measuring device. When crystal formation i
16、s detected inthe specimen, the temperature is recorded and the specimen inthe test chamber is warmed, while being continuously stirredand monitored by the optical system, until the crystals in thespecimen completely disappear. The temperature of the speci-men when the last crystals disappear is reco
17、rded as the freezingpoint (automatic fiber optical method).5. Significance and Use5.1 The freezing point of an aviation fuel is an index of thelowest temperature of its utility for certain applications. Solidhydrocarbon crystals can restrict the flow of fuel in the fuelsystem of the aircraft. The te
18、mperature of the fuel in the aircrafttank normally decreases during flight depending on aircraftspeed, altitude, and flight duration. The freezing point of thefuel must always be lower than the minimum operational fueltemperature.5.2 Petroleum blending operations require precise measure-ment of the
19、freezing point.5.3 This test method expresses results with a resolution of0.1C.5.4 This test method eliminates most of the operator timeand judgment required by Test Method D2386.5.5 When the specification requires the use of Test MethodD2386, do not substitute this test method or any other method.6
20、. Apparatus (see Annex A1)6.1 Automatic Fiber Optical Apparatus4The apparatus asdescribed in Annex A1 shall consist of a test chamber com-prising a jacketed test tube supported in a jacketed enclosureconfiguration that is capable of cooling and heating the testspecimen to the temperatures required i
21、n the test. The appara-tus shall have a nitrogen purge collar as part of the closureassembly for the test chamber, which prevents moisture fromcombining with the test specimen. The apparatus shall becapable of measuring the temperature of the test specimen,continuously stirring the test specimen at
22、the prescribed rate,automatically cooling and then heating the test specimen,monitoring the test specimen with an electronic optical systemfor appearance and disappearance of the crystals in the testspecimen under the conditions of the test, and recording theappearance and disappearance temperatures
23、.6.2 Circulating Bath, refrigeration unit equipped with acirculating pump capable of maintaining the temperature of aquantity of methyl alcohol at least 20C lower than theminimum test specimen temperature expected.NOTE 3To achieve a typical test chamber cooling condition of -75C,the circulating bath
24、 should be capable of achieving -85 to -90C, sinceapproximately 5 to 10C is consumed in the circulation lines andinsulation.6.3 Instrument and Software VersionThe HCP 860 appa-ratus with V.22 software was used in the 2003 InterlaboratoryProgram2that determined the precision and relative bias inSecti
25、on 13.7. Reagents and Materials7.1 Cooling Medium, Methyl AlcoholA commercial ortechnical grade of anhydrous methanol is suitable for use as thecooling medium. (WarningExtremely flammable. Toxic.May be fatal or cause blindness if swallowed or inhaled.)7.2 Nitrogen Gas, dry nitrogen gas which has a d
26、ew pointbelow the lowest temperature expected to be attained by thetest specimen under the conditions of the test. (WarningCompressed gas under high pressure. Inert gas can be anasphyxiant when inhaled.)7.3 Cleaning Solvents, suitable for cleaning and drying thetest chamber, such as petroleum naphth
27、a and methyl alcohol.(WarningFlammable. Liquid causes eye burns. Vapor harm-ful. Toxic. May be fatal or cause blindness if swallowed orinhaled.)8. Sampling8.1 Obtain a sample in accordance with Practice D4057 orD4177.8.2 At least 25 mL of sample is required for each test. Referto Practice D4057.9. P
28、reparation of Apparatus9.1 Prepare the apparatus for operation in accordance withthe manufacturers instructions.9.2 Clean and dry the test chamber with petroleum naphthato rinse out any previous specimen followed by a second rinseof alcohol to remove naphtha. Dry with moisture-free air orgas. Ensure
29、 that moisture does not remain inside the testchamber.9.3 Prepare the refrigerated circulating bath for operation inaccordance with the manufacturers instructions and allow it toattain a temperature lower than -75C. The temperature of thealcohol, at the test chamber, shall not be below -80C unlessth
30、e expected freezing point is below -60C.9.4 Confirm that the supply of nitrogen purge gas is con-nected and regulated in accordance with the manufacturersinstructions.10. Calibration and Standardization10.1 Ensure that all of the manufacturers instructions forcalibrating, checking, and operating the
31、 apparatus are followedincluding calibration of the temperature measuring systemagainst a certified standard temperature device.10.2 A sample with a mutually agreed upon freezing pointsuch as one from an interlaboratory test program, Test MethodD2386 or equivalent, can be used to verify performance
32、of theapparatus within the precisions of this test method.4The sole source of supply of the apparatus known to the committee at this timeis Herzog model HCP 860 Freezing Point Analyzer with software version V.22,available from Walter Herzog, Lauda, Germany. If you are aware of alternativesuppliers,
33、please provide this information to ASTM International Headquarters.Your comments will receive careful consideration at a meeting of the responsibletechnical committee,1which you may attend.D7154 05 (2010)211. Procedure11.1 Measure out 25 6 1 mL of the fuel, and transfer it tothe clean, dry, test cha
34、mber. Support the test chamber in theposition recommended by the manufacturer, enclosing the topof the test chamber with a closure assembly supporting thestirrer, temperature measuring device, optical system, andnitrogen purge collar. Adjust the temperature measuring deviceposition, if necessary, so
35、 that it is positioned in the center of thetest chamber. Ensure that the bottom of the temperaturemeasuring device is between 35 to 45 mm from the bottom ofthe test chamber. Connect the cooling medium inlet and outlethoses to the respective connections on the test chamberaccording to the manufacture
36、rs instructions.11.2 Start the operation of the apparatus according to themanufacturers instructions. This shall enable the flow of thecooling medium for cooling of the specimen, the flow of thepurge gas, and the stirring of the specimen continuously andwithout interruption. The stirrer shall move u
37、p and downvertically at the rate of 1 to 1.5 cycles per second, taking carethat the stirrer loops approach the bottom of the test chamberon the downstroke and remain below the specimen surface onthe upstroke.11.3 The fiber optical system shall monitor the specimen forthe appearance of hydrocarbon cr
38、ystals. The apparatus shalldisregard any cloud-like formation, due to water, that appearsin the test specimen at approximately -10C and does notincrease in intensity as the specimen temperature decreases.11.4 After the crystals are detected, the apparatus shalldiscontinue the flow of the cooling med
39、ium. Allow the testspecimen to warm by circulating nitrogen gas in place of thecooling medium. The apparatus shall continue the stirring ofthe specimen in the prescribed manner.11.5 The fiber optical system shall continue to monitor thehydrocarbon crystals in the specimen and the apparatus shallreco
40、rd the temperature when the crystals completely disappear.11.6 After the hydrocarbon crystals have disappeared, theapparatus shall discontinue the stirring and the warmingmedium.11.7 Remove the test chamber from the apparatus and cleanand dry according to the manufacturers instructions.12. Report12.
41、1 Report the temperature of crystal disappearance re-corded in 11.5 to the nearest 0.1C as the freezing point, TestMethod D7154.13. Precision and Bias13.1 PrecisionThe precision of this test method as deter-mined by the statistical examination of the interlaboratory2testresults is as follows:13.1.1
42、RepeatabilityThe difference between two resultsobtained by the same operator with the same apparatus underconstant operating conditions on identical test material would,in the long run, in the normal and correct operation of this testmethod, exceed 0.5C only in one case in twenty.13.1.2 Reproducibil
43、ityThe difference between two singleand independent results obtained by different operators work-ing in different laboratories on identical test material would, inthe long run, in the normal and correct operation of this testmethod, exceed 1.9C only in one case in twenty.13.2 BiasBecause there are n
44、o liquid hydrocarbon mix-tures of known freezing point, which simulate aviation fuels,bias cannot be established.13.3 Relative BiasThe degree of agreement between thistest method and Test Method D2386 from the 2003 interlabo-ratory program cited has been performed in accordance withPractice D6708. N
45、o relative bias was observed. The crossmethod reproducibility (Rxy) identified in the research report2between this test method and Test Method D2386 is 2.2.13.4 The precision statements were derived from a 2003interlaboratory cooperative test program.2Participants ana-lyzed 13 samples sets comprised
46、 of various aviation fuels overthe temperature range of -60 to -42C. Eleven laboratoriesparticipated with the automatic fiber optical method and fifteenwith the manual Test Method D2386 or IP 16 test methods. Theprecision statistics were compiled and calculated based on the0.1C resolution offered by
47、 the automatic fiber optical method.Information on the types of samples and their respectiveaverage freezing point is contained in the research report.214. Keywords14.1 automatic freezing point; automatic fiber opticalmethod; aviation gasoline; aviation turbine fuels; freezingpointD7154 05 (2010)3AN
48、NEX(Mandatory Information)A1. AUTOMATIC FIBER OPTICAL FREEZING POINT APPARATUSA1.1 Test Chamber, configuration of jacketed test tube andjacketed enclosure as described in A1.1.1 and A1.1.2.A1.1.1 Jacketed Test Tube, borosilicate glass tube, double-walled, unsilvered vessel as shown in Fig. A1.1, sim
49、ilar to aDewar flask, the space between the test tube and the outer glassjacket being filled at atmospheric pressure with dry nitrogen orair.A1.1.2 Jacketed Enclosure, similar to the one shown in Fig.A1.1, with connections for circulation of cooling/heatingmedium around the jacketed test tube. The enclosure shallpermit the necessary depth of immersion of the jacketed testtube into the cooling/heating medium and is attached aroundthe jacketed test tube. The immersion depth is determined asfollowsthe meniscus of the test specimen when placed i
