1、Designation: D7154 15IP 52812Standard 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 revision, the ye
2、ar 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 theversion of s
3、oftware (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 to publish asepar
4、ate test method with a different standard designation.1. Scope*1.1 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 which closely mim
5、ics the apparatus and proceduredescribed in Test Method D2386.1.2 The measuring range of the apparatus is from 70 C to0 C, however the precision statements were derived only fromsamples with freezing point temperatures from 60 C to42 C.NOTE 2Typical aviation fuel has freezing point temperatures in t
6、he60 C to 40 C 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 be regarde
7、d 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 determine
8、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 Automatic S
9、ampling of Petroleum andPetroleum ProductsD5901 Test Method for Freezing Point of Aviation Fuels(Automated Optical Method) (Withdrawn 2010)4D6708 Practice for Statistical Assessment and Improvementof Expected Agreement Between Two Test Methods thatPurport to Measure the Same Property of a MaterialE1
10、 Specification 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,1This test method
11、 is under the jurisdiction of ASTM CommitteeD02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.07 on Flow Properties.Current edition approved April 1, 2015. Published April 2015. Originallyapproved in 2005. Last previous edition approved in 201
12、0 as D7154 05 (2010).DOI: 10.1520/D7154-15.2Supporting data (2003 Interlaboratory 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 A
13、STM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.4The last approved version of this historical standard is referenced onwww.astm.org.*A Summary of Changes section appears at the end of this s
14、tandardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1disappear when the temperature 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 me
15、thod, nthe robotic auto-mation of a manual procedure and apparatus and use of fiberoptics to transmit crystal detection signals to and from thespecimen test chamber.4. Summary of Test Method4.1 After insertion of 25 mL of the test specimen into a testchamber, the test specimen is cooled while being
16、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 is detected inthe specimen, the temperature is recorded and the specimen inthe test chamber is warmed, while being contin
17、uously 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 recorded as the freezingpoint (automatic fiber optical method).5. Significance and Use5.1 The freezing point of an aviation
18、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 temperature of the fuel in the aircrafttank normally decreases during flight depending on aircraftspeed, altitude, and fli
19、ght 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 freezing point.5.3 This test method expresses results with a resolution of0.1 C.5.4 This test method eliminates most of
20、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. Apparatus (see Annex A1)6.1 Automatic Fiber Optical Apparatus5The apparatus asdescribed in Annex A1 shall consist of
21、a test chambercomprising a jacketed test tube supported in a jacketedenclosure configuration that is capable of cooling and heatingthe test specimen to the temperatures required in the test. Theapparatus shall have a nitrogen purge collar as part of theclosure assembly for the test chamber, which pr
22、events moisturefrom combining with the test specimen. The apparatus shall becapable of measuring the temperature of the test specimen,continuously stirring the test specimen at the prescribed rate,automatically cooling and then heating the test specimen,monitoring the test specimen with an electroni
23、c optical systemfor appearance and disappearance of the crystals in the testspecimen under the conditions of the test, and recording theappearance and disappearance temperatures.6.2 Circulating Bath, refrigeration unit equipped with acirculating pump capable of maintaining the temperature of aquanti
24、ty of methyl alcohol at least 20 C lower than theminimum test specimen temperature expected.NOTE 3To achieve a typical test chamber cooling condition of 75 C,the circulating bath should be capable of achieving 85 C to 90 C,since approximately 5 C to 10 C is consumed in the circulation lines andinsul
25、ation.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 inSection 13.7. Reagents and Materials7.1 Cooling Medium, Methyl AlcoholA commercial ortechnical grade of anhydrous methanol
26、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 dew pointbelow the lowest temperature expected to be attained by thetest specimen under the conditions of the test. (Wa
27、rningCompressed 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 naphtha and methyl alcohol.(WarningFlammable. Liquid causes eye burns. Vapor harm-ful. Toxic. May be fatal or cause blindnes
28、s 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. Preparation of Apparatus9.1 Prepare the apparatus for operation in accordance withthe manufacturers instructions.9.2 Cl
29、ean 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 that moisture does not remain inside the testchamber.9.3 Prepare the refrigerated circulating bath for operation inac
30、cordance with the manufacturers instructions and allow it toattain a temperature lower than 75 C. The temperature of thealcohol, at the test chamber, shall not be below 80 C unlessthe expected freezing point is below 60 C.9.4 Confirm that the supply of nitrogen purge gas is con-nected and regulated
31、in accordance with the manufacturersinstructions.5The 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, please pr
32、ovide this information to ASTM International Headquarters.Your comments will receive careful consideration at a meeting of the responsibletechnical committee,1which you may attend.D7154 15210. Calibration and Standardization10.1 Ensure that all of the manufacturers instructions forcalibrating, check
33、ing, and operating the 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
34、to verify performance of theapparatus within the precisions of this test method.11. Procedure11.1 Measure out 25 mL 6 1 mL of the fuel, and transfer itto the clean, dry, test chamber. Support the test chamber in theposition recommended by the manufacturer, enclosing the topof the test chamber with a
35、 closure assembly supporting thestirrer, temperature measuring device, optical system, andnitrogen purge collar. Adjust the temperature measuring deviceposition, if necessary, so that it is positioned in the center of thetest chamber. Ensure that the bottom of the temperaturemeasuring device is betw
36、een 35 mm to 45 mm from the bottomof the test chamber. Connect the cooling medium inlet andoutlet hoses to the respective connections on the test chamberaccording to the manufacturers instructions.11.2 Start the operation of the apparatus according to themanufacturers instructions. This shall enable
37、 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 up and downvertically at the rate of 1 to 1.5 cycles per second, taking carethat the stirrer loops approach the bottom o
38、f 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 crystals. The apparatus shalldisregard any cloud-like formation, due to water, that appearsin the test specimen at approx
39、imately 10 C 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 medium. Allow the testspecimen to warm by circulating nitrogen gas in place of thecooling medium. The apparatus shall cont
40、inue 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 shallrecord the temperature when the crystals completely disappear.11.6 After the hydrocarbon crystals have disappeared, theappa
41、ratus 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. Report12.1 Report the temperature of crystal disappearance re-corded in 11.5 to the nearest 0.1 C as the freezing point, TestMet
42、hod 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 RepeatabilityThe difference between two resultsobtained by the same operator with the same apparatus underconstant ope
43、rating conditions on identical test material would,in the long run, in the normal and correct operation of this testmethod, exceed 0.5 C only in one case in twenty.13.1.2 ReproducibilityThe difference between two singleand independent results obtained by different operators work-ing in different lab
44、oratories on identical test material would, inthe long run, in the normal and correct operation of this testmethod, exceed 1.9 C only in one case in twenty.13.2 BiasBecause there are no liquid hydrocarbon mix-tures of known freezing point, which simulate aviation fuels,bias cannot be established.13.
45、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. No relative bias was observed. The crossmethod reproducibility (Rxy) identified in the research report2between this t
46、est 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 of various aviation fuels overthe temperature range of 60 C to 42 C. Eleven laboratoriesparticipated with the autom
47、atic fiber optical method and fifteenwith the manual Test Method D2386 or IP 16 test methods. Theprecision statistics were compiled and calculated based on the0.1 C resolution offered by the automatic fiber optical method.Information on the types of samples and their respectiveaverage freezing point
48、 is contained in the research report.214. Keywords14.1 automatic freezing point; automatic fiber opticalmethod; aviation gasoline; aviation turbine fuels; freezingpointD7154 153ANNEX(Mandatory Information)A1. AUTOMATIC FIBER OPTICAL FREEZING POINT APPARATUSA1.1 Test Chamber, configuration of jackete
49、d test tube andjacketed enclosure as described in A1.1.1 and A1.1.2.A1.1.1 Jacketed Test Tube, borosilicate glass tube,doublewalled, unsilvered vessel as shown in Fig. A1.1, similarto a Dewar flask, the space between the test tube and the outerglass jacket being filled at atmospheric pressure with drynitrogen or air.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 immer
