1、Designation: D5236 13D5236 17Standard Test Method forDistillation of Heavy Hydrocarbon Mixtures (Vacuum PotstillMethod)1This standard is issued under the fixed designation D5236; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、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.1. Scope*1.1 This test method covers the procedure for distillation of heavy hydrocarbon mixtures having initial boiling p
3、oints greaterthan 150C (300F),150 C (300 F), such as heavy crude oils, petroleum distillates, residues, and synthetic mixtures. It employsa potstill with a low pressure drop entrainment separator operated under total takeoff conditions. Distillation conditions andequipment performance criteria are s
4、pecified and typical apparatus is illustrated.1.2 This test method details the procedures for the production of distillate fractions of standardized quality in the gas oil andlubricating oil range as well as the production of standard residue. In addition, it provides for the determination of standa
5、rddistillation curves to the highest atmospheric equivalent temperature possible by conventional distillation.1.3 The maximum achievable atmospheric equivalent temperature (AET) is dependent upon the heat tolerance of the charge.For most samples, a temperature up to 565C (1050F)565 C (1050 F) can be
6、 attained. This maximum will be significantly lowerfor heat sensitive samples (for example, heavy residues) and might be somewhat higher for nonheat sensitive samples.1.4 The recommended distillation method for crude oils up to cutpoint 400C (752F)400 C (752 F) AET is Test MethodD2892. This test met
7、hod can be used for heavy crude oils with initial boiling points greater than 150C (302F).150 C (302 F).However, distillation curves and fraction qualities obtained by these methods are not comparable.1.5 This test method contains the following annexes:1.5.1 Annex A1Test Method for Determination of
8、Temperature Response Time,1.5.2 Annex A2Practice for Calibration of Sensors,1.5.3 Annex A3Test Method for Dehydration of a Wet Sample of Oil,1.5.4 Annex A4Practice for Conversion of Observed Vapor Temperature to Atmospheric Equivalent Temperature (AET), and1.5.5 Annex A5Test Method for Determination
9、 of Wettage.1.6 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.1.7 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 t
10、o establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use. For specific warnings, see 6.5.4.2, 6.5.6.3, 6.9.3, 9.5, 9.7, and A2.3.1.3.1.8 WARNINGMercury has been designated by many regulatory agencies as a hazardous material that can ca
11、use centralnervous system, 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 websitehtt
12、p:/www.epa.gov/mercury/faq.htmfor additional information. Users should be awarethat selling mercury and/or mercury containing products into your state or country may be prohibited by law.1.9 This international standard was developed in accordance with internationally recognized principles on standar
13、dizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:21 This test method is under the jurisdiction ofAST
14、M Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of SubcommitteeD02.08 on Volatility.Current edition approved May 1, 2013May 1, 2017. Published May 2013May 2017. Originally approved in 1992. Last previous edition approved in 20112013 as D5236 03(20
15、11). 13. DOI: 10.1520/D5236-13.10.1520/D5236-17.2 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.This document
16、 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 adequately depict all changes accurately, ASTM recommends that users consult prior editions as appr
17、opriate. 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 ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United Sta
18、tes1D941 Test Method for Density and Relative Density (Specific Gravity) of Liquids by Lipkin Bicapillary Pycnometer (Withdrawn1993)3D1217 Test Method for Density and Relative Density (Specific Gravity) of Liquids by Bingham PycnometerD1250 Guide for Use of the Petroleum Measurement TablesD1298 Test
19、 Method for Density, Relative Density, or API Gravity of Crude Petroleum and Liquid Petroleum Products byHydrometer MethodD1480 Test Method for Density and Relative Density (Specific Gravity) of Viscous Materials by Bingham PycnometerD2892 Test Method for Distillation of Crude Petroleum (15-Theoreti
20、cal Plate Column)D4057 Practice for Manual Sampling of Petroleum and Petroleum ProductsD4177 Practice for Automatic Sampling of Petroleum and Petroleum ProductsD5002 Test Method for Density and Relative Density of Crude Oils by Digital Density Analyzer3. Terminology3.1 Definitions of Terms Specific
21、to This Standard:3.1.1 boil-up rate, nthe quantity of vapor entering the distillation head per unit time.3.1.1.1 DiscussionIt is approximately equal to the takeoff rate, differing only by the parasitic heat losses. It is expressed in millilitres per hour fora head of any given internal diameter or m
22、illilitres per hour per square centimetre of cross-sectional area of the throat forcomparative purposes.3.1.2 condenser, nthe apparatus connected to the outlet of the distillation head in which condensation of the product occurs.3.1.3 distillation flask, nthe flask, of glass or metal, in which the c
23、harge is boiled.3.1.3.1 DiscussionThe flask is sometimes called a kettle or pot.3.1.4 distillation head, nthe section immediately above the distillation flask containing the entrainment separator.3.1.5 distillation pressure (or operating pressure), nthe pressure measured in the distillation head jus
24、t before the outlet to therecovery system.3.1.6 distillation temperature (or vapor temperature), nthe temperature of the vapors in the distillation head at the point ofmeasurement.3.1.7 loading, nthe volume of charge relative to the cross-sectional area of the neck.3.1.8 pressure drop, nthe differen
25、ce between the operating pressure and the pressure measured in the distillation flask.3.1.8.1 DiscussionIt is a result of the friction developed by driving the vapors through the system expressed in kilopascals (mm Hg).3.1.9 spillover point, nthe lowest point in the head above the entrainment separa
26、tor over which the vapors can flow to thecondensing region.3.1.10 static hold-up (or wettage), nthe amount of liquid material remaining on the inside of the walls of the apparatus afterthe distillation has been completed.3.1.10.1 DiscussionIn this test method, it includes wettage of the distillation
27、 flask in the case of the steel flasks, but not in the case of glass flasks thatare removed for weighing after the distillation is completed.3.1.11 takeoff rate, nthe quantity of product removed per unit time.3.1.11.1 DiscussionIt is approximately equal to the boil-up rate differing only by parasiti
28、c heat losses.3 The last approved version of this historical standard is referenced on www.astm.org.D5236 1724. Summary of Test Method4.1 A weighed volume of sample is distilled at absolute pressures between 6.66.6 kPa and 0.013 kPa (50 and 0.1 mm (50 mmHg and 0.1 mm Hg) at specified distillation ra
29、tes. Cuts are taken at preselected temperatures. Records of vapor temperature,operating pressure, and other variables are made at intervals, including at each cutpoint.4.2 The mass of each fraction is obtained. Distillation yields by mass are calculated from the mass of each fraction relative tothe
30、total mass recovery.4.3 The density of each fraction is obtained. Distillation yields by volume are calculated from the volume computed for eachfraction at 15C (59F)15 C (59 F) relative to the total recovery.4.4 Distillation curves of temperature versus mass or volume percent, or both, are drawn usi
31、ng the data from 4.2 and 4.3.5. Significance and Use5.1 This test method is one of a number of tests conducted on heavy hydrocarbon mixtures to characterize these materials fora refiner or a purchaser. It provides an estimate of the yields of fractions of various boiling ranges.5.2 The fractions mad
32、e by this test method can be used alone or in combination with other fractions to produce samples foranalytical studies and quality evaluations.5.3 Residues to be used in the manufacture of asphalt can also be made but may not always be suitable. The long heat soakingthat occurs in this test method
33、may alter some of the properties.NOTE 1While the practice of reblending distillates with residue can be done to produce a lighter residue, it is not recommended because it producesblends with irregular properties.5.4 Details of cutpoints must be mutually agreed upon before the test begins.5.5 This i
34、s a complex procedure involving many interacting variables. It is most important that at the time of first use of a newapparatus, its components be checked as detailed in AnnexA1 and AnnexA2 and that the location of the vapor temperature sensorbe verified as detailed in 6.5.3 and Fig. 1.6. Apparatus
35、6.1 Four sizes of apparatus, based upon the internal diameter of the distillation head (25, 36, 50, and 70 mm), (25 mm, 36 mm,50 mm, and 70 mm), are allowed.4 The apparatus (see Fig. 2) consists of a flask with heating mantles, an upper compensator, anda head containing an entrainment separator. Att
36、ached to the head are the vapor temperature sensor, a connection for the vacuumgauge, a condenser, a rundown line, a product receiver(s), and a vacuum pumping line with pump. The parts are connected byvacuum-tight joints to facilitate servicing.6.2 Distillation Flask:6.2.1 The sizes specified for fl
37、asks are at least 50 % larger than the size of the charge to provide space for suppression of foamand for bubble breaking. The size of the charge for each size of still is determined from the loading factor. The recommendedloading factor is between 200200 mLand 400 mLof charge per square centimetre
38、of cross sectional cross-sectional area in the neckof the head. Table 1 shows the range of charge volume that is recommended with each size of apparatus.6.2.2 Flasks are made of borosilicate glass except those larger than 10 L, which are made of stainless steel for reasons of safety.6.2.3 The flask
39、is fitted with a thermowell reaching to within 6 mm of the bottom and offset from the center to avoid a stirringbar. In the case of glass flasks, the bottom shall be slightly flattened or slightly concave, but not perfectly flat to facilitate therotation of the magnetic stirrer. Steel flasks can hav
40、e a cooling coil for rapid quenching of the distillation in an emergency. Fig.3 shows a typical example.6.3 Stirring SystemA magnetically driven stirring bar approximately 3-mm3 mm diameter and 20-mm20 mm long shall beprovided for the glass flasks, or 6-mm6 mm diameter by 50-mm50 mm long for the ste
41、el flasks. The edges shall be rounded tominimize grinding the wall of the flask. The external magnetic drive must be capable of rotating the bar in the flask when locateddirectly below and touching the mantle. The drive can be used to support the apparatus above. An adjustable jacking mechanismis re
42、commended for raising and lowering the stirrer.6.4 Heating System:6.4.1 The flask shall be heated by means of a nickel reinforced nickel-reinforced quartz fabric heating mantle on the lower halfso that boiling rates of up to 150 mL/h per cm2 of the cross sectional cross-sectional area of the neck ca
43、n be maintained. A heatdensity of 0.5 W/cm2 is adequate. Usually two or more circuits are used to improve heat control by applying automatic heat tothe bottom circuit.6.4.2 A temperature sensor shall be located between the wall of the flask and the mantle for control of the skin temperature.4 Cooke,
44、 Industrial and Engineering Chemistry, Vol 55, 1963, p. 36.D5236 1736.4.3 The upper half of the flask shall be covered with a mantle to compensate for heat losses. A heat density of 0.20.2 WW/cmcm2 is adequate.6.5 Distilling Head:6.5.1 The head shall conform to the details shown in Fig. 1. It shall
45、be made of borosilicate glass and be totally enclosed in asilvered glass vacuum jacket having a permanent vacuum of less than 0.0001 kPa (0.00075 mm Hg).6.5.2 The head shall be enclosed in a heat insulating heat-insulating system such as a glass fabric mantle capable of maintainingthe outer wall of
46、the glass vacuum jacket at a temperature 5C5 C below the internal vapor temperature in the head. For thispurpose, the vacuum jacket shall have a temperature sensor fastened to the outer wall of the jacket at a point level with the vaportemperature sensor and opposite to the outlet arm of the head.6.
47、5.3 The head shall be fitted with an adapter to support the vapor temperature sensor so that it is held centered in the neck withthe top of the sensing tip 33 mm 6 1 mm below the spillover point. This dimension can be checked by removing the temperaturesensor and inserting in its place a copper wire
48、 having a short right angle bend at the bottom. By feeling for the spillover point,the distance from the top joint of the adaptor can be found. Laying the wire on the temperature sensor will then permit checkingof this dimension.6.5.4 The vapor temperature sensor shall be either a platinum resistanc
49、e thermometer, a thermocouple with the junction headfused to the lower tip of the well, or any other device which meets the requirements in 6.5.4 and 6.5.4.1. It shall have a responsetime of less than 60 s as described in Annex A1.6.5.4.1 The vapor temperature measuring device shall have an accuracy of 0.5C0.5 C or better and be measured with aresolution of 0.1C0.1 C or better.STILL HEAD DIMENSION CHARTSize A B C D E F G H I25 mm 85 mm 75 mm 64 mm 47 mm ID 40 mm OD 45 mm 35/25 28/15 35 mm36 mm 90 mm 75 mm 64 mm 68 mm ID 57
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