ASTM D2386-2015 Standard Test Method for Freezing Point of Aviation Fuels《航空燃料冻结点的标准试验方法》.pdf

1、Designation: D2386 06 (Reapproved 2012)D2386 15Designation: 16/15Standard Test Method forFreezing Point of Aviation Fuels1This standard is issued under the fixed designation D2386; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, th

2、e 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.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope*1.1 This test method cove

3、rs the determination of the temperature below which solid hydrocarbon crystals may form in aviationturbine fuels and aviation gasoline.NOTE 1The interlaboratory program that generated the precisions for this test method did not include aviation gasoline.1.2 The values stated in SI units are to be re

4、garded as standard. No other units of measurement are included in this standard.1.3 WARNINGMercury has been designated by many regulatory agencies as a hazardous material that can cause centralnervous system, kidney and liver damage. Mercury, or its vapor, may be hazardous to health and corrosive to

5、 materials. Cautionshould be taken when handling mercury and mercury containing products. See the applicable product Material Safety Data Sheet(MSDS) for details and EPAs websitehttp:/www.epa.gov/mercury/faq.htmfor additional information. Users should be awarethat selling mercury and/or mercury cont

6、aining products into your state or country may be prohibited by law.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the a

7、pplicability of regulatorylimitations prior to use. For specific warning statements, see 5.4, Section 6, and 8.28.3.2. Referenced Documents2.1 ASTM Standards:2D910 Specification for Leaded Aviation GasolinesD1655 Specification for Aviation Turbine FuelsD3117 Test Method for Wax Appearance Point of D

8、istillate Fuels (Withdrawn 2010)3D4057 Practice for Manual Sampling of Petroleum and Petroleum ProductsD4177 Practice for Automatic Sampling of Petroleum and Petroleum ProductsE1 Specification for ASTM Liquid-in-Glass ThermometersE77 Test Method for Inspection and Verification of Thermometers2.2 Ene

9、rgy Institute Standard:IP Standards for Petroleum and Its Products, Part 1Products IP 16/1543. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 freezing point, nin aviation fuels, the fuel temperature at which solid hydrocarbon crystals, formed on cooling, disappearwhen the temper

10、ature of the fuel is allowed to rise under specified conditions of test.3.1.2 crystallization point, nthe temperature at which crystals of hydrocarbons first appear when the test sample is cooled.1 This test method is under the jurisdiction ofASTM Committee D02 on Petroleum Products, Liquid Fuels, a

11、nd Lubricants and is the direct responsibility of SubcommitteeD02.07 on Flow Properties.Current edition approved April 15, 2012June 1, 2015. Published April 2012June 2015. Originally approved in 1965. Last previous edition approved in 20062012 asD2386D2386 06 (2012).06. DOI: 10.1520/D2386-06R12.10.1

12、520/D2386-15.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 The last approved version of this historical s

13、tandard is referenced on www.astm.org.4 Available from Energy Institute, 61 New Cavendish St., London, WIG 7AR, U.K., http:/www.energyinst.org.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previo

14、us version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Chang

15、es section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14. Significance and Use4.1 The freezing point of an aviation fuel is the lowest temperature at which the fuel remains free of solid hydrocar

16、bon crystalsthat can restrict the flow of fuel through filters if present in the fuel system of the aircraft. The temperature of the fuel in the aircrafttank normally falls during flight depending on aircraft speed, altitude, and flight duration. The freezing point of the fuel mustalways be lower th

17、an the minimum operational tank temperature.4.2 Freezing point is a requirement in Specifications D910 and D1655.5. Apparatus5.1 Jacketed Sample TubeAdouble-walled, unsilvered vessel, similar to a Dewar flask, the space between the inner and outertube walls being filled at atmospheric pressure with

18、dry nitrogen or air. The mouth of the sample tube shall be closed with a stoppersupporting the thermometer and moisture-proof collar through which the stirrer passes (Fig. 1). A cork stopper is recommended.5.2 CollarsMoisture-proof collars as shown in Fig. 2 shall be used to prevent condensation of

19、moisture.5.3 StirrerShall be made of 1.6-mm brass 1.6 mm brass or stainless steel rod bent into a smooth three-loop spiral at thebottom.NOTE 2The stirrer may be mechanically actuated as described in the apparatus section of Test Method D3117.5.4 Vacuum FlaskAn unsilvered vacuum flask (WarningImplosi

20、on hazard) having the minimum dimensions shown in Fig.1 shall be used to hold an adequate volume of cooling liquid and permit the necessary depth of immersion of the jacketed sampletube.5.5 ThermometerAtotal immersion type, having a range from 8080 C to +20C,+20 C, designated asASTM No. 114C/IPNo. 1

21、4C. (See Specification E1, or Appendix A, IP Standard Thermometers, Volume 2, IP Standard Methods for Analysis andTesting of Petroleum and Related Products.)FIG. 1 Freezing Point ApparatusD2386 152NOTE 3The accuracy of this thermometer is to be checked in accordance with Test Method E77, at temperat

22、ures of 0, 40, 60, and 75C.0 C,40 C, 60 C, and 75 C.56. Reagents and Materials6.1 AcetoneTechnical Grade acetone is suitable for the cooling bath, provided it does not leave a residue on drying.(WarningExtremely flammable.)6.2 Ethanol or Ethyl AlcoholA commercial or technical grade of dry ethanol is

23、 suitable for the cooling bath. (WarningExtremely flammable.)6.3 Isopropyl AlcoholA commercial or technical grade of dry isopropyl alcohol is suitable. (WarningExtremelyflammable.)6.4 Methanol or Methyl AlcoholA commercial or technical grade of dry methanol is suitable for the cooling bath.(WarningE

24、xtremely flammable and toxic.)6.5 Carbon Dioxide (Solid) or Dry IceA commercial grade of dry ice is suitable for use in the cooling bath.(WarningExtremely cold, 78C.78 C. Carbon dioxide (solid) liberates gases that can cause suffocation. Contact with skincauses burns, freezing, or both.)5 The U.S. N

25、ational Bureau of Standards, Gaithersburg, MD, and the British National Physical Laboratory, Teddington, England are able to certify thermometers at thesetemperatures.NOTE 1All dimensions are in mm and 60.1 mm 60.1 mm glass wall thickness is 1 mm.1 mm.FIG. 2 Moistureproof Collars for Freezing Point

26、ApparatusD2386 1536.6 Liquid NitrogenAcommercial or technical grade of liquid nitrogen is suitable for the cooling bath when the freezing pointis lower than 65C.65 C. (WarningExtremely cold, 196C.196 C. Liquid nitrogen liberates gases that can causesuffocation. Contact with skin causes burns, freezi

27、ng, or both.)6.7 Fiberglasscommercial grade, for use in moisture-proof collar B.6.8 Dehydrating AgentUse one of the following:6.8.1 Calcium sulfate (CaS04), granulated anhydrous calcium sulfate, for use as a desiccant in moisture-proof collar B, or toassist in drying the nitrogen gas or air (5.2) us

28、ed with collar A.6.8.2 Silica gel, 1.7 mm, for use as a desiccant in moisture-proof collar B, or to assist in drying the nitrogen gas or air (5.2) usedwith collar A. (WarningSilica gel dyed with cadmium salts can cause cancer by inhalation.)7. Sampling7.1 Obtain a sample in accordance with Practice

29、D4057 or Practice D4177.7.2 At least 25 mL 25 mL of specimen is required for each test.7.3 Keep the sample in a tightly sealed container at ambient room temperature to minimize introduction of any moisture.Minimize exposure of the sample to sources of heat.8. Procedure8.1 CollarAssemble the collar (

30、5.2), thermometer (5.5) and stirrer (5.3) into the cork. To prevent the ingress of water into thetest portion, it is important that an effective moisture-proof collar as prepared in accordance with 8.1.1 or 8.1.2 is used.8.1.1 Collar type A, flush with nitrogen or dry air before fitting to the jacke

31、ted sample tube, and throughout the entiredetermination.NOTE 4The air can be effectively dried by passing through absorbent tubes filled with dehydrating agents (6.8.1 and 6.8.2).8.1.2 Collar type B, fill with fiberglass (6.7) and a suitable dehydrating agent (6.8.1 and 6.8.2) as shown in Fig. 2. Th

32、e fiberglassshall be replaced every fourth test. The dehydrating agent should be renewed at intervals of not more than 3 months or when acolor change shows it to be ineffective8.2 Measure out 2525 mL6 1 mL 1 mL of the fuel and transfer it to the clean, dry, jacketed sample tube. Close the tube tight

33、lywith the cork holding the stirrer, thermometer, and moisture proof collar and adjust the thermometer position so that its bulb doesnot touch the walls of the tube flask and is approximately in the center. The bulb of the thermometer should be 1010 mm to 15mm 15 mm from the bottom of the sample tub

34、e. (WarningDo not add solid carbon dioxide to liquid nitrogen.)NOTE 5Performance of this test method can be difficult, since the specimen tube is immersed in a coolant medium that evolves gas bubbles duringthe test. This can interfere with visual observations. In addition, the crystals that are form

35、ed in the specimen can be difficult to recognize, and they canappear in a variety of manifestations. It is strongly suggested that operators seek guidance from experienced operators of this test method to assist themin the correct recognition of these crystals.NOTE 6This test method should be perfor

36、med under laboratory conditions where there is an ample supply of light. Some crystals can be very faintin appearance and difficult to observe under inadequate lighting conditions.8.3 Clamp the jacketed sample tube so that it extends as far as possible into the vacuum flask (WarningImplosion hazard)

37、containing the cooling medium (Note 67). The surface of the sample should be approximately 1515 mm to 20 mm 20 mm belowthe level of the coolant. Unless the medium is cooled by mechanical refrigeration, add solid carbon dioxide as necessary throughoutthe test to maintain the coolant level in the vacu

38、um flask.NOTE 7Acetone and either methyl, ethyl, or isopropyl alcohols are suitable. All of these require cautious handling. Liquid nitrogen may also be usedas a coolant instead of liquids cooled with solid carbon dioxide for fuel samples which have a freezing point below 65C.65 C. Mechanicalrefrige

39、ration is permitted. Where used the refrigerant temperature should be 70C70 C to 80C.80 C.8.4 Stir the fuel continuously, moving the stirrer up and down at the rate of 11 cycless to 1.51.5 cycles cycles/s, s, taking carethat the stirrer loops approach the bottom of the flask on the downstroke and re

40、main below the specimen surface on the upstroke.It is permissible for momentary interruption of stirring while performing some operations of the procedure (see Note 78). Observethe specimen continuously for the appearance of hydrocarbon crystals. Disregard any cloud that appears at approximately10C1

41、0 C and does not increase in intensity as the temperature decreases, because this cloud is due to water. Record thetemperature at which hydrocarbon crystals appear. Remove the jacketed sample tube from the coolant and allow the specimen towarm by ambient air, stirring it continuously at 11 cycless t

42、o 1.51.5 cycles cycles/s. s. Continue to observe the specimencontinuously for the disappearance of hydrocarbon crystals. Record the temperature at which the hydrocarbon crystals completelydisappear.NOTE 8Because the gases released by the coolant can obscure observations, the sample tube can be remov

43、ed from the coolant for observations. Thetube can be removed for periods no longer than 10 s. 10 s. If crystals are observed to have already formed, the specimen temperature should be notedand the specimen allowed to be warmed by ambient air, with continued stirring, to at least 5C5 C above the temp

44、erature at which the crystals disappear.The specimen should then be re-immersed in the coolant and allowed to cool. Remove the specimen from the coolant slightly above the noted temperature,and observe for appearance of the crystals.NOTE 9It is recommended to compare the crystal appearance temperatu

45、re with the crystal disappearance temperature. The appearance temperatureD2386 154should be colder than the disappearance temperature. If this is not the case, this is an indication that the crystals were not correctly recognized. Also, thedifference between these temperatures should typically be no

46、 greater than 6C.6 C.9. Report9.1 The observed freezing point determined in Section 8 shall be corrected by applying the relevant thermometer correctionresulting from the checks described in Note 3. Where the observed freezing point falls between two calibration temperatures, thecorrection at the ob

47、served temperature shall be obtained by linear interpolation. Report the corrected temperature of crystaldisappearance to the nearest 0.5C0.5 C as the freezing point, Test Method D2386.NOTE 10False results can be obtained if the temperature of the test portion is not uniform during the cooling and w

48、arming cycles. To obtain a uniformtemperature, the test portion must be stirred strictly in accordance with the procedure described.NOTE 11Contamination by other petroleum products can cause crystals to appear at much higher temperatures than normally expected for aviationfuel freeze points. In orde

49、r to identify such contamination, it is important that observations are made throughout the test, both in the cooling and warmingcycles.NOTE 12When results are desired in degrees Fahrenheit, test results obtained in degrees Celsius should be converted to the nearest whole degreeFahrenheit. Interim Celsius freezing points should carry the best precision available for subsequent conversion to degrees Fahrenheit.10. Precision and Bias610.1 PrecisionThe precision of this test method