1、Designation: D5236 03 (Reapproved 2011)D5236 13Standard 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
2、 of 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.1. Scope Scope*1.1 This test method covers the procedure for distillation of heavy hydrocarbon mixtures
3、having initial boiling points greaterthan 150C (300F), such as heavy crude oils, petroleum distillates, residues, and synthetic mixtures. It employs a potstill with alow pressure drop entrainment separator operated under total takeoff conditions. Distillation conditions and equipmentperformance crit
4、eria are specified 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
5、 of standarddistillation 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) can be att
6、ained. This maximum will be significantly lower for heat sensitivesamples (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) AET is Test Method D2892. This testmethod can be used f
7、or heavy crude oils with initial boiling points greater than 150C (302F). However, distillation curves andfraction 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 Temperature Response Time,1.5.2
8、 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 of Wettage.1.6 The values stat
9、ed 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 to establish appropriate safety
10、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 cause centralnervous system, kidn
11、ey 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.htmfo
12、r additional information. Users should be awarethat selling mercury and/or mercury containing products into your state or country may be prohibited by law.2. Referenced Documents2.1 ASTM Standards:2D941 Test Method for Density and Relative Density (Specific Gravity) of Liquids by Lipkin Bicapillary
13、Pycnometer (Withdrawn1993)31 This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.08 onVolatility.Current edition approved Dec. 1, 2011May 1, 2013. Published April 2012May 2013. Originally approved
14、in 1992. Last previous edition approved in 20072011 asD523603(2007).D5236 03(2011). DOI: 10.1520/D5236-03R11.10.1520/D5236-13.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information,
15、refer to the standards Document Summary page on the ASTM website.3 The last approved version of this historical standard is referenced on www.astm.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 th
16、e previous 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
17、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 States1D1217 Test Method for Density and Relative Density (Specific Gravity) of Liquids by Bingham PycnometerD1250 Guide for Use of the Pet
18、roleum Measurement TablesD1298 Test 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 Distillat
19、ion of Crude Petroleum (15-Theoretical 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. Terminolog
20、y3.1 Definitions of Terms Specific 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
21、of any given internal diameter or millilitres 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
22、, of glass or metal, in which the charge 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 me
23、asured in the distillation head just 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
24、.3.1.8 pressure drop, nthe difference 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 th
25、e head above the entrainment separator 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 i
26、ncludes wettage of the distillation 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
27、-up rate differing only by parasitic heat losses.D5236 1324. Summary of Test Method4.1 A weighed volume of sample is distilled at absolute pressures between 6.6 and 0.013 kPa (50 and 0.1 mm Hg) at specifieddistillation rates. Cuts are taken at preselected temperatures. Records of vapor temperature,
28、operating pressure, and other variablesare 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 total mass recovery.4.3 The density of each fraction is obtained. Distillation
29、yields by volume are calculated from the volume computed for eachfraction at 15C (59F) relative to the total recovery.4.4 Distillation curves of temperature versus mass or volume percent, or both, are drawn using the data from 4.2 and 4.3.5. Significance and Use5.1 This test method is one of a numbe
30、r 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 made by this test method can be used alone or in combination with other fractions to produce
31、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 may alter some of the properties.NOTE 1While the practice of reblending distillates with r
32、esidue 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 is a complex procedure involving many interacting variables. It is most important that at t
33、he 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. Apparatus6.1 Four sizes of apparatus, based upon the internal diameter of the distillation head (25
34、, 36, 50, and 70 mm), are allowed.4 Theapparatus (see Fig. 2) consists of a flask with heating mantles, an upper compensator, and a head containing an entrainmentseparator.Attached to the head are the vapor temperature sensor, a connection for the vacuum gage,gauge, a condenser, a rundownline, a pro
35、duct receiver(s), and a vacuum pumping line with pump. The parts are connected by vacuum-tight joints to facilitateservicing.6.2 Distillation Flask:6.2.1 The sizes specified for flasks are at least 50 % larger than the size of the charge to provide space for suppression of foamand for bubble breakin
36、g. The size of the charge for each size of still is determined from the loading factor. The recommendedloading factor is between 200 and 400 mL of charge per square centimetre of cross sectional area in the neck of the head. Table1 shows the range of charge volume that is recommended with each size
37、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 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 fl
38、asks, the bottom shall be slightly flattened or slightly concave, but not perfectly flat to facilitate therotation of the magnetic stirrer. Steel flasks can have a cooling coil for rapid quenching of the distillation in an emergency. Fig.3 shows a typical example.6.3 Stirring SystemA magnetically dr
39、iven stirring bar approximately 3-mm diameter and 20-mm long shall be provided forthe glass flasks, or 6-mm diameter by 50-mm long for the steel flasks. The edges shall be rounded to minimize grinding the wallof the flask. The external magnetic drive must be capable of rotating the bar in the flask
40、when located directly below and touchingthe mantle. The drive can be used to support the apparatus above. An adjustable jacking mechanism is recommended for raisingand lowering the stirrer.6.4 Heating System:6.4.1 The flask shall be heated by means of a nickel reinforced quartz fabric heating mantle
41、 on the lower half so that boilingrates of up to 150 mL/h per cm2 of the cross sectional area of the neck can be maintained.Aheat density of 0.5 W/cm2 is adequate.Usually two or more circuits are used to improve heat control by applying automatic heat to the bottom circuit.6.4.2 A temperature sensor
42、 shall be located between the wall of the flask and the mantle for control of the skin temperature.6.4.3 The upper half of the flask shall be covered with a mantle to compensate for heat losses. A heat density of 0.2 W/cm2 isadequate.4 Cooke, Industrial and Engineering Chemistry, Vol 55, 1963, p. 36
43、.D5236 1336.5 Distilling Head:6.5.1 The head shall conform to the details shown in Fig. 1. It shall 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 insu
44、lating system such as a glass fabric mantle capable of maintaining the outer wallof the glass vacuum jacket at a temperature 5C below the internal vapor temperature in the head. For this purpose the vacuumjacket shall have a temperature sensor fastened to the outer wall of the jacket at a point leve
45、l with the vapor temperature sensorand opposite to the outlet arm of the head.6.5.3 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 3 6 1 mm below the spillover point. This dimension can be checke
46、d by removing the temperature sensorand inserting in its place a copper wire having a short right angle bend at the bottom. By feeling for the spillover point, the distancefrom the top joint of the adaptor can be found. Laying the wire on the temperature sensor will then permit checking of thisdimen
47、sion.6.5.4 The vapor temperature sensor shall be either a platinum resistance 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 Ann
48、ex A1.6.5.4.1 The vapor temperature measuring device shall have an accuracy of 0.5C or better and be measured with a resolutionof 0.1C or better.6.5.4.2 The vapor temperature measuring device shall be calibrated over the full range of useful temperatures in combinationwith its associated instrument
49、at the time of first use and at least once per year thereafter as described in A2.2.2. Alternatively,certified sensors may be used, provided the calibration of the sensor and its associated recording instrument can be traced backSTILL 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 mm OD 56 mm 65/40 35/25 35 mm50 mm 110 mm 100 mm 75 mm 94 mm ID 79 mm OD 79 mm 75/50 35/25 45 mm70 mm 140 mm 100 mm 100 mm 131 mm ID 111 mm OD 1011 mm 102/75 50/
