1、Designation: D2500 16D2500 16a British Standard 4458Standard Test Method forCloud Point of Petroleum Products and Liquid Fuels1This standard is issued under the fixed designation D2500; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisio
2、n, 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.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope*1.1 This test method
3、 covers only petroleum products and biodiesel fuels that are transparent in layers 40 mm in thickness, andwith a cloud point below 49 C.NOTE 1The interlaboratory program consisted of petroleum products of Test Method D1500 color of 3.5 and lower. The precisions stated in this testmethod may not appl
4、y to samples with ASTM color higher than 3.5.1.2 The values stated in SI units are to be regarded 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,
5、kidney and liver damage. Mercury, or its vapor, may be hazardous to health and corrosive to 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.h
6、tmfor additional information. Users should be awarethat selling mercury and/or mercury containing 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 use
7、r of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use. For specific hazard statements, see Section 7.2. Referenced Documents2.1 ASTM Standards:2D1500 Test Method for ASTM Color of Petroleum Products (ASTM Color S
8、cale)D6300 Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and LubricantsD7962 Practice for Determination of Minimum Immersion Depth and Assessment of Temperature Sensor Measurement DriftE1 Specification for ASTM Liquid-in-Glass ThermometersE1137
9、Specification for Industrial Platinum Resistance ThermometersE2877 Guide for Digital Contact Thermometers2.2 Energy Institute Standard:3Specifications for IP Standard Thermometers3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 biodiesel, na fuel comprised of mono-alkyl esters
10、of long chain fatty acids derived from vegetable oils or animal fats,designated B100.3.1.1.1 DiscussionBiodiesel is typically produced by a reaction of vegetable oil or animal fat with an alcohol such as methanol or ethanol in the1 This test method is under the jurisdiction ofASTM Committee D02 on P
11、etroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of SubcommitteeD02.07 on Flow Properties.Current edition approved Jan. 1, 2016June 1, 2016. Published February 2016June 2016. Originally approved in 1966. Last previous edition approved in 20112016 asD2500 11.D2500 16.
12、DOI: 10.1520/D2500-16.10.1520/D2500-16A.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 Available from Ener
13、gy Institute, 61 New Cavendish St., London, WIG 7AR, U.K., http:/www.energyinst.org.uk.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 previous version. Becauseit may not be technically possible to
14、 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 Changes section appears at the end of this standardCopyright
15、ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1presence of a catalyst to yield mono-esters and glycerin. The fuel typically may contain up to 14 different types of fatty acids thatare chemically transformed into fatty acid methyl esters (FAME)
16、.3.1.2 biodiesel blend, na blend of biodiesel fuel with petroleum-based diesel fuel designated BXX, where XX is the volume% of biodiesel.3.1.3 cloud point, nin petroleum products and biodiesel fuels, the temperature of a liquid specimen when the smallestobservable cluster of hydrocarbonwax crystals
17、first occurs upon cooling under prescribed conditions.3.1.3.1 DiscussionTo many observers, the cluster of wax crystals looks like a patch of whitish or milky cloud, hence the name of the test method.The cloud appears when the temperature of the specimen is low enough to cause wax crystals to form. F
18、or many specimens, thecrystals first form at the lower circumferential wall of the test jar where the temperature is lowest. The size and position of thecloud or cluster at the cloud point varies depending on the nature of the specimen. Some samples will form large, easily observable,clusters, while
19、 others are barely perceptible.3.1.3.2 DiscussionUpon cooling to temperatures lower than the cloud point, clusters of crystals will grow in multiple directions; for example, aroundthe lower circumference of the test jar, towards the center of the jar, or vertically upwards. The crystals can develop
20、into a ringof cloud along the bottom circumference, followed by extensive crystallization across the bottom of the test jar as temperaturedecreases. Nevertheless, the cloud point is defined as the temperature at which the crystals first appear, not when an entire ringor full layer of wax has been fo
21、rmed at the bottom of the test jar.3.1.3.3 DiscussionIn general, it is easier to detect the cloud point of samples with large clusters that form quickly, such as paraffinic samples. Thecontrast between the opacity of the cluster and the liquid is also sharper. In addition, small brightly-reflective
22、spots can sometimesbe observed inside the cluster when the specimen is well illuminated. For other more difficult samples, such as naphthenic,hydrocracked, and those samples whose cold flow behavior have been chemically altered, the appearance of the first cloud can beless distinct. The rate of crys
23、tal growth is slow, the opacity contrast is weak, and the boundary of the cluster is more diffuse. Asthe temperature of these specimens decrease below the cloud point, the diffuse cluster will increase in size and can form a generalhaze throughout. A slight haze throughout the entire sample, which s
24、lowly becomes more apparent as the temperature of thespecimen decreases, can also be caused by traces of water in the specimen instead of crystal formation (see Note 5). With thesedifficult samples, drying the sample prior to testing can eliminate this type of interference.3.1.3.4 DiscussionThe purp
25、ose of the cloud point method is to detect the presence of the wax crystals in the specimen; however trace amounts ofwater and inorganic compounds may also be present. The intent of the cloud point method is to capture the temperature at whichthe liquids in the specimen begin to change from a single
26、 liquid phase to a two-phase system containing solid and liquid. It is notthe intent of this test method to monitor the phase transition of the trace components, such as water.3.1.4 digital contact thermometer (DCT), nan electronic device consisting of a digital display and associated temperaturesen
27、sing probe.3.1.4.1 DiscussionThis device consists of a temperature sensor connected to a measuring instrument; this instrument measures the temperature-dependent quantity of the sensor, computes the temperature from the measured quantity, and provides a digital output. This digitaloutput goes to a d
28、igital display and/or recording device that may be internal or external to the device. These devices are sometimesreferred to as a “digital thermometer”.3.1.4.2 DiscussionPortable electronic thermometers (PET) is an acronym sometimes used to refer to a subset of the devices covered by this definitio
29、n.D2500 16a24. Summary of Test Method4.1 The specimen is cooled at a specified rate and examined periodically. The temperature at which a cloud is first observed atthe bottom of the test jar is recorded as the cloud point.5. Significance and Use5.1 For petroleum products and biodiesel fuels, cloud p
30、oint of a petroleum product is an index of the lowest temperature of theirutility for certain applications.6. Apparatus (see Fig. 1)6.1 Test Jar, clear, cylindrical glass, flat bottom, 33.2 mm to 34.8 mm outside diameter and 115 mm to 125 mm in height. Theinside diameter of the jar may range from 30
31、 mm to 32.4 mm within the constraint that the wall thickness be no greater than1.6 mm. The jar should be marked with a line to indicate sample height 54 mm 6 3 mm above the inside bottom.6.2 Temperature Measuring DeviceEither liquid-in-glass thermometers as described in 6.2.1 or digital contact ther
32、mometer(DCT) meeting the requirements described in 6.2.2.6.2.1 Liquid-in-Glass Thermometers, having ranges shown below and conforming to the requirements as prescribed inSpecification E1 or Specifications for IP Standard Thermometers.ThermometerNumberThermometer Temperature Range ASTM IPHigh cloud a
33、nd pour 38 C to +50 C 5C 1CLow cloud and pour 80 C to +20 C 6C 2CNOTE 1All dimensions are in milllimetres.FIG. 1 Apparatus for Cloud Point TestD2500 16a36.2.2 Digital Contact Thermometer Requirements:Parameter RequirementDCT Guide E2877 Class G or betterTemperature range 65 C to 90 CDisplay resoluti
34、on 1 C minimum, preferably 0.1 CSensor type PRT, thermistor, thermocoupleSensor 3 mm O.D. with a sensing element less than 10 mm in lengthMinimum immersion Less than 40 mm per Practice D7962Sample immersion depth As shown in Fig. 1 or subsection 8.3Display accuracy 500 mK (0.5 C) for combined probe
35、and sensorResponse time less than or equal to 25 s as defined in Specification E1137Drift less than 500 mK (0.5 C) per yearCalibration error less than 500 mK (0.5 C) over the range of intended use.Calibration range 40 C or lower to 85 CCalibration data 4 data points evenly distributed over calibrati
36、on range with data included in calibration report.Calibration report From a calibration laboratory with demonstrated competency in temperature calibration which is traceable to a nationalcalibration laboratory or metrology standards bodyNOTE 2When the DCT display is mounted on the end to the probes
37、sheath, the test jar with the probe inserted will be unstable. To resolve this, itis recommended that the probe be less than 30 cm in length but no less than 15 cm. A 5 cm long stopper that has a low thermal conductivity, withapproximately half of it inserted in the sample tube, will improve stabili
38、ty.6.2.2.1 The DCT calibration drift shall be checked at least annually by either measuring the ice point or against a referencethermometer in a constant temperature bath at the prescribed immersion depth to ensure compliance with 6.2.2. See PracticeD7962.NOTE 3When a DCTs calibration drifts in one
39、direction over several calibration checks, that is, ice point, it may be an indication of deteriorationof the DCT.6.3 Cork, to fit the test jar, bored centrally for the test thermometer.6.4 Jacket, metal or glass, watertight, cylindrical, flat bottom, about 115 mm in depth, with an inside diameter o
40、f 44.2 mm to45.8 mm. It shall be supported free of excessive vibration and firmly in a vertical position in the cooling bath of 6.7 so that notmore than 25 mm projects out of the cooling medium and shall be capable of being cleaned.6.5 Disk, cork or felt, 6 mm thick to fit loosely inside the jacket.
41、6.6 Gasket, ring form, about 5 mm in thickness, to fit snugly around the outside of the test jar and loosely inside the jacket. Thegasket may be made of rubber, leather, or other material that is elastic enough to cling to the test jar and hard enough to hold itsshape. Its purpose is to prevent the
42、test jar from touching the jacket.6.7 Bath or Baths, maintained at prescribed temperatures with a firm support to hold the jacket vertical. The required bathtemperatures may be maintained by refrigeration if available, otherwise by suitable cooling mixtures. Cooling mixtures commonlyused for bath te
43、mperatures shown are in Table 1.7. Reagents and Materials7.1 AcetoneTechnical grade acetone is suitable for the cooling bath, provided it does not leave a residue on drying.(WarningExtremely flammable.)7.2 Carbon Dioxide (Solid) or Dry IceA commercial grade of dry ice is suitable for use in the cool
44、ing bath.7.3 Petroleum NaphthaA commercial or technical grade of petroleum naphtha is suitable for the cooling bath. (WarningCombustible. Vapor harmful.)7.4 Sodium Chloride CrystalsCommercial or technical grade sodium chloride is suitable.TABLE 1 Cooling Mixtures and Bath TemperaturesBath Temperatur
45、eIce and water 0 C 1.5 CCrushed ice and sodium chloride crystals, orAcetone or petroleum naphtha or methanol or ethanol (see Section 7)with solid carbon dioxide added to give the desired temperature18 C 1.5 CAcetone or petroleum naphtha or methanol or ethanol (see Section 7)with solid carbon dioxide
46、 added to give the desired temperature33 C 1.5 CAcetone or petroleum naphtha or methanol or ethanol (see Section 7)with solid carbon dioxide added to give the desired temperature51 C 1.5 CAcetone or petroleum naphtha or methanol or ethanol (see Section 7)with solid carbon dioxide added to give the d
47、esired temperature69 C 1. 5 CD2500 16a47.5 Sodium SulfateA reagent grade of anhydrous sodium sulfate should be used when required (see Note 6).7.6 Ethanol or Ethyl AlcoholA commercial or technical grade of dry ethanol is suitable for the cooling bath. (WarningFlammable. Denatured, cannot be made non
48、toxic.)7.7 Methanol or Methyl AlcoholA commercial or technical grade of dry methanol is suitable for the cooling bath.(WarningFlammable. Vapor harmful.)8. Procedure8.1 Bring the sample to be tested to a temperature at least 14 C above the expected cloud point. Remove any moisture presentby a method
49、such as filtration through dry lintless filter paper until the oil is perfectly clear, but make such filtration at a temperatureof at least 14 C above the approximate cloud point.8.2 Pour the sample into the test jar to the level mark.8.3 If using a liquid-in-glass thermometer and the expected cloud point is above 36 C then use the high cloud and pour pointthermometer; otherwise use the low cloud and pour thermometer. Close the test jar tightly by the cork carrying the testthermometer, and adj
