1、Designation: D4893 94 (Reapproved 2009)Standard Test Method forDetermination of Pitch Volatility1This standard is issued under the fixed designation D4893; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision.
2、A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the percentof pitch volatility.1.2 Since this test method is empirical, strict adherence
3、 tothe procedure is necessary.1.3 The values stated in SI units are to be regarded as thestandard. The values in parentheses are given for informationonly.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of
4、this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Summary of Test Method2.1 An aluminum weighing dish with about 15 g of speci-men is introduced into the cavity of a metal block heated andmaintained at 350C
5、(662F). After 30 min 6 10 s duringwhich the volatiles are swept away from the surface of theliquid pitch by preheated nitrogen, the sample is taken out andallowed to cool down in the desiccator. The pitch volatility isdetermined by the sample weight loss and reported as percentweight loss.3. Signifi
6、cance and Use3.1 This test is useful in evaluating and characterizing pitchphysical properties in comparing the consistency of shipmentsand sources of supply.4. Apparatus4.1 Aluminum Block,2412-in. outside diameter, composedof two sections (Figs. 1-4).4.1.1 The top block is maintained at a chosen co
7、nstanttemperature according to the signal from the thermocoupleinserted into the thermowell No. 1 near the center of the block.A proportional temperature controller regulates the heat input.Two insulated handles are attached to this part for easyhandling. An additional thermowell No. 2, located in t
8、he centerof the block, accommodates another thermocouple used onlyfor the determination of the rate of temperature rise of thepitch. When the screw at the bottom of the No. 2 well is takenout, the thermocouple can then be pushed down and inserted inpitch.4.1.2 The bottom block has a cavity for the a
9、luminumweighing dish.Aspiral channel cut around the periphery of thispart serves for preheating the nitrogen introduced at themeasured rate (10 cm3/min) into the block for purging vola-tiles.4.1.3 The test temperature, the same as that in the top block,is maintained by the second proportional temper
10、ature control-ler according to the signals of a thermocouple inserted in athermowell No. 3 of the bottom block. There is a hole in thecenter of the bottom cylinder to accommodate the sampleplatform, a rod with a stainless steel disk welded to its top. Thealuminum sample dish containing the sample re
11、sts on top ofthis disk during the test. The aluminum sample dish can belifted out of the cavity by raising the disk up to the upper rimof the cavity.4.2 Aluminum Weighing Dish.4.3 Flowmeter, 0 to 25-cm3/min range.4.4 Nitrogen Cylinder, equipped with a pressure regulator.4.5 Timer, with an alarm.4.6
12、Aluminum Plate, 5-by-5-in., approximately 20-gage.5. Dehydration of Sample5.1 Hard PitchIf the solid bulk sample contains freewater, air-dry a representative portion in a forced-draft oven at50C (122F).5.2 Soft Pitch (Softening Point 60C (140F)If thepresence of water is indicated by surface foam on
13、heating,maintain a representative portion of the bulk sample at atemperature between 125 and 150C (251 and 302F) in anopen container until the surface is free of foam. Take care notto overheat, and remove heat source immediately when foamsubsides.1This test method is under the jurisdiction of ASTM C
14、ommittee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.05 on Properties of Fuels, Petroleum Coke and Carbon Material.Current edition approved Oct. 1, 2009. Published November 2009. Originallyapproved in 1989. Last previous edition approved in 2004 as D48
15、9394(2004).DOI: 10.1520/D4893-94R09.2An aluminum block that may be obtained on special order from KoppersCompany, Inc., 1005 Wm. Pitt Way, Pittsburgh, PA 15238, has been foundsatisfactory for this purpose; or drawings of block will be furnished by Koppersupon request. If you are aware of alternative
16、 suppliers, please provide thisinformation to ASTM International Headquarters. Your comments will receivecareful consideration at a meeting of the responsible technical committee,1whichyou may attend.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,
17、 United States.6. Preparation of Working Sample6.1 Crush sample to pass No. 4 mesh (4760 m).7. Preparation of Apparatus7.1 Assemble the apparatus so that the exit opening in theupper block is aligned with bottom nitrogen inlet fitting of thebottom block. Both top and bottom blocks are heated to the
18、testtemperature, 350C (662F), using the proportional tempera-ture controllers. Avoid heating the upper block and lower blockwhen separated from each other.8. Procedure8.1 Weigh 15 g of prepared sample into a tared aluminumweighing dish with precision of 0.1 mg.8.2 Start nitrogen purge system at a ra
19、te 10 cm3/min 6 0.1cm3/min (10 mL/min 6 0.1 mL/min).8.3 Place top block onto bottom block, align the nitrogeninlet with nitrogen outlet, and heat to test temperature of 350C(662F).8.4 Remove top block. Raise the sample platform upslightly above the rim of heating cavity and support with thealuminum
20、plate inserted between the sample platform and toprim of the bottom block. Place the aluminum sample dishcontaining the sample onto the sample platform. Remove theinserted aluminum plate from below the sample platform andlower the sample carefully into the heated cavity. Close thebottom block with t
21、he top block and realign the nitrogen inletwith nitrogen outlet. This operation should be performed asquickly as possible to avoid excessive heat loss from the heatedcavity.8.5 Heat for 30 min 6 10 s. Remove top block, raise sampleplatform, insert aluminum plate under the sample platform,sweep the s
22、ample off the sample platform on to the plate, andset aside.8.6 Close the bottom block with the top block, realign thenitrogen inlet and outlet and allow the temperature in theblocks to stabilize before inserting subsequent sample.FIG. 1 Schematic of the Volatility ApparatusD4893 94 (2009)28.7 When
23、sample has cooled, approximately 2 min afterremoval or when crust has formed on top of sample, setaluminum dish containing sample into desiccator for 30 min.Determine weight loss.8.8 Report in percent, mass loss for test temperature, 350C.V 5 b 3 100!/a (1)where:V = volatility, %, mass loss,b = mass
24、 loss, g, anda = net mass of sample, g.8.9 The exit opening of nitrogen purge, the sample platform,and the seat between the blocks must be kept free of deposits.For cleaning use acetone and a drill bit for opening the nitrogenexit.9. Determination of Unit Heat-up Rate9.1 The volatility test temperat
25、ure should be maintained atthe same level for the total duration of the test. Because this isnot possible, the required temperature level should be reachedwithin the shortest time after placing the sample into thepreheated blocks. The heat-up rate is determined with aselected control pitch sample. T
26、he temperature of pitch ismeasured and recorded with the provided thermocouple and aseparate temperature indicator (not provided). For that reasonthe thermocouple is introduced through the upper block afterremoving the closing screw and its immersion in the pitchsample is adjusted so that it is cove
27、red with pitch but does nottouch the bottom of the aluminum weighing dish.9.2 The procedure for preheating the blocks and introducingthe pitch sample into the cavity of the volatility apparatus isidentical to the actual volatility procedure.9.3 The temperature of pitch should level off, that is, the
28、temperature rise should become less than 1C/min, within theinterval not longer than 10 min after the start of the experiment.Plot time versus temperature, taking data every 2 min (Fig. 5).10. Precision310.1 RepeatabilityDuplicate values by the same operatorshall not be considered suspect unless they
29、 differ by more than0.2 %.10.2 ReproducibilityThe values reported by each of twolaboratories representing the arithmetic average of duplicatedeterminations shall not be considered suspect unless thevalues differ by more than 0.3 %.11. Keywords11.1 coal; pitch; tar; volatility3Supporting data have be
30、en filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR: D08-1004.FIG. 2 Internal Schematic Lower BlockD4893 94 (2009)3FIG. 3 Schematic External Bottom BlockD4893 94 (2009)4FIG. 4 Schematic Top BlockD4893 94 (2009)5ASTM International takes no position respecti
31、ng the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This stand
32、ard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM Internation
33、al Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.T
34、his standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).FIG. 5 Temperature Rise Measured in a Calibration SampleD4893 94 (2009)6
