1、Designation: D4715 98 (Reapproved 2012)Standard Test Method forCoking Value of Tar and Pitch (Alcan)1This standard is issued under the fixed designation D4715; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revisi
2、on. 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 cokingvalue of tar and pitch having an ash content not over 0.5 %, asdetermined
3、by Test Method D2415.1.2 Coking values by this test method are higher than thoseobtained by Test Method D2416. See the bias statement inSection 13.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.4 This standard does not pu
4、rport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D
5、850 Test Method for Distillation of Industrial AromaticHydrocarbons and Related MaterialsD2415 Test Method for Ash in Coal Tar and PitchD2416 Test Method for Coking Value of Tar and Pitch(Modified Conradson)D4296 Practice for Sampling PitchE11 Specification for Woven Wire Test Sieve Cloth and TestSi
6、eves3. Summary of Test Method3.1 A test portion of the tar or pitch is heated for a specifiedtime at 550 6 10C in an electric furnace. The percentage ofresidue is reported as the coking value.4. Significance and Use4.1 This test method is useful for indicating the relativecoke-forming propensities a
7、nd for evaluating and characteriz-ing tars and pitches. The test method can also be used as oneelement in establishing the uniformity of shipments or sourcesof supply.5. Apparatus5.1 Porcelain Crucible, tall form, 30 mL capacity, height of37 mm and diameter 43 mm, with lids of the overlapping type.5
8、.2 Nickel Crucible, 100 to 130 mL capacity, height of 64mm and diameter of 60 mm, with lids.5.3 Wire SupportStainless steel wire support, fitting intothe nickel crucible, used to keep the porcelain crucible (5.1)inplace within the nickel crucible (5.2). This support shall allowa separation of 10 6 1
9、 mm between the bases of the twocrucibles (see Fig. 1).5.4 Crucible TrayA suitable crucible tray to support thenickel crucibles should be made so that there is at least 7 mmof space between the bottom of the crucible and the base of thefurnace.5.5 Electric Furnace, capable of being controlled at 550
10、 610C.5.6 Sieves1 mm (U.S. Standard No. 18), 300-m (U.S.Standard No. 50) and 212m (U.S. Standard No. 70), con-forming to Specification E11.6. Reagents and Materials6.1 Calcined Petroleum CokeUse the fraction whichpasses a 1-mm mesh sieve (U.S. Standard No. 18) and isretained by a 212m mesh sieve (U.
11、S. Standard No. 70).7. Bulk Sampling7.1 Samples from shipments shall be taken in accordancewith Practice D4296, and shall be free of foreign substances.Thoroughly mix the sample immediately before removing arepresentative portion for the determination or for dehydration.8. Dehydration of Sample8.1 H
12、ard PitchIf the solid bulk sample contains freewater, air-dry a representative portion.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.05 on Properties of Fuels, Petroleum Coke and Carbon Materi
13、al.Current edition approved Nov. 1, 2012. Published November 2012. Originallyapproved in 1987. Last previous edition approved in 2008 as D471598(2008)1.DOI: 10.1520/D4715-98R12.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. F
14、or Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States18.2 Soft PitchIf the presence of water is indicated bysurface foam on
15、heating, maintain a representative portion ofthe bulk sample at a temperature between 125 and 150C in anopen container until the surface is free from foam. Take carenot to overheat, and remove heat source immediately whenfoam subsides.8.3 TarDehydrate a representative portion of the bulksample at at
16、mospheric pressure using a simple side-armdistillation apparatus similar to the one in Test Method D850and stop the distillation when the temperature reaches 170C.Separate any oil from the water that has distilled over (ifcrystals are present, warm sufficiently to ensure their solution),and thorough
17、ly mix the oil with the residual tar in the still afterthe latter has cooled to a moderate temperature.9. Preparation of Working Specimen9.1 Hard PitchIf the pitch can be crushed at roomtemperature, prepare a 20 6 1 g working specimen by suitablecrushing, mixing, and quartering of a representative p
18、ortion ofthe dry specimen. The crushing can be performed with a smalljaw crusher and a mortar and pestle. No particle in therepresentative specimen should be larger than 5 mm in anydimension. Crush this specimen so that it will pass a 300 m(U.S. Standard No. 50) mesh sieve. If the ambient temperatur
19、eis high, the operation can be facilitated by chilling the samplebeforehand.9.2 Soft Pitch and TarFor soft pitch and tar samples, meltthe sample and take a sufficient amount of the molten mass forthe test. The melting temperature must not exceed 150C andthe melting period not longer than 10 min. It
20、is also possible totransfer the required portion of a soft pitch directly to theporcelain crucible, without preliminary treatment.9.3 Preservation of SamplesStore samples as large lumpsor as solidified melts in closed containers. Discard workingsamples 24 h after crushing and sieving as changes in c
21、ompo-sition sometimes occur in pulverized pitch.10. Procedure10.1 For greater accuracy, carry out the determination induplicate.10.2 Heat a clean porcelain crucible with its lid in theelectric furnace, controlled at 550 6 10C, for 2 h. Aftercooling to ambient temperature in a desiccator, weigh to th
22、enearest 1 mg.10.3 Weigh into the crucible, to the nearest 1 mg, arepresentative portion of 1 6 0.05 g of the test specimen. Placethe wire support in the nickel crucible and make a bed 10 6 1mm thick on the base of the crucible with the petroleum coke.Place the porcelain crucible containing the test
23、 portion in thewire support so that it sits on the bed of petroleum coke. Coverthe porcelain crucible with its lid and completely fill the spacebetween the two crucibles with the petroleum coke so that theporcelain crucible is completely embedded. Take care to avoidcontamination of the sample by the
24、 coke. Cover the nickelcrucible with its lid.10.4 Place the prepared crucible on the crucible support andplace the whole in the electric furnace controlled at 550 610C, as quickly as possible, in order to avoid heat losses.10.4.1 There should be a space of not less than 7 mmbetween the nickel crucib
25、le and the floor, walls, and roof of thefurnace. The space between the crucible and the door, and theback wall of the furnace should not be less than 5 cm.10.5 After 2.5 h, remove the nickel crucible from thefurnace and allow to cool for 5 to 10 min. Lift the porcelaincrucible out of the coke by mea
26、ns of the wire support, brushand wipe free from adhering coke powder, taking care to avoidcontamination. Place the crucible and contents, covered, in adesiccator and allow to cool to ambient temperature. Weigh tothe nearest 1 mg.NOTE 1To clean the porcelain crucibles and lids, discard the residuesan
27、d burn off carbonaceous matter by igniting at 700 to 1000C in anelectric furnace.11. Calculation11.1 Calculate the coking value of the sample as follows:Coking value, mass% 5 100A/B (1)where:A = mass of residue, g, andB = mass of sample, g.11.1.1 If the determination was carried in duplicate, report
28、the mean value.12. Report12.1 Report the coking value to the nearest 0.1 mass %.13. Precision and Bias13.1 The following criteria shall be used for judging theacceptability of results (95 % probability).13.1.1 RepeatabilityDuplicate values by the same opera-tor shall not be considered suspect unless
29、 the determinedpercentages differ by more than 1.2 % absolute.13.1.2 ReproducibilityThe values reported by each of twolaboratories, representing the arithmetic average of duplicatedetermination, shall not be considered suspect unless thereported percentages differ by more than 2.3 % absolute.13.2 Bi
30、asCoking values by this test method are about 2percentage points higher than those obtained by Test MethodD2416.FIG. 1 Assembly of Nickel and Porcelain CruciblesD4715 98 (2012)214. Keywords14.1 Alcan; coke-forming; coking value; fixed carbon;pitch; residue; tarASTM International takes no position re
31、specting 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
32、 standard 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 Inter
33、national 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 b
34、elow.This 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). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D4715 98 (2012)3
