1、Designation: D 2416 84 (Reapproved 2004)An American National StandardStandard Test Method forCoking Value of Tar and Pitch (Modified Conradson)1This standard is issued under the fixed designation D 2416; the number immediately following the designation indicates the year oforiginal adoption or, in t
2、he case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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
3、 an ash content not over 0.5 % asdetermined by Test Method D 2415.1.2 Coking values by this test method are practically thesame as those obtained by Test Method D 189, but results aremore reproducible. The apparatus used is identical, except thatan electric furnace is substituted for the gas flame.1
4、.3 This standard does not purport 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 Do
5、cuments2.1 ASTM Standards:2D 140 Practice for Sampling Bituminous MaterialsD 189 Test Method for Conradson Carbon Residue ofPetroleum ProductsD 370 Test Method for Dehydration of Oil-Type Preserva-tivesD 2415 Test Method for Ash in Coal Tars and PitchE11 Specification for Wire Cloth and Sieves for T
6、estingPurposes3. Summary of Test Method3.1 A sample of the tar or pitch is vaporized and pyrolizedfor a specified time at a specified temperature in specialstandardized equipment that limits the available oxygen sup-ply. The percentage of residue is reported as the coking value.4. Significance and U
7、se4.1 This test method is useful for indicating the relativecoke-forming propensities and for evaluating and characteriz-ing tars and pitches. This test method can also be used as oneelement in establishing the uniformity of shipments or sourcesof supply.5. Apparatus (see Fig. 1)5.1 CrucibleWide-for
8、m, a, either porcelain, glazedthroughout, or silica, a; 29 to 31-mL capacity, 46 to 49 mm inrim diameter.5.2 Skidmore CrucibleIron crucible, b, flanged andringed, 65 to 82-mL capacity, 53 to 57 mm inside and 60 to 67mm outside diameter of flange, 37 to 39 mm in height, suppliedwith a cover without d
9、elivery tubes and having the verticalopening closed. The horizontal opening of about 6.5 mm shallbe kept clean. The outside diameter of the flat bottom shall be30 to 32 mm.5.3 Metal Crucible Spun sheet-iron or nickel crucible, c,with cover; 78 to 82 mm in outside diameter at the top, 58 to60 mm in h
10、eight, and approximately 0.8 mm in thickness. Atthe bottom of this crucible, and level before each test, shall bea layer of about 25 mL of sand, or enough to bring theSkidmore crucible, with cover on, nearly to the top of thesheet-iron crucible. The sand shall be dry and screened to passthrough a 65
11、-mesh screen and to be retained on a 200-meshscreen.5.4 Wire SupportTriangle (65 mm) of bare Nichrome wire1.5 to 2.0 mm in cross section, having an opening small enoughto support the bottom of the metal crucible (see 5.3). Thetriangle, d, shall have its arms bent to form a cradle that willsupport th
12、e metal crucible with its bottom level with the bottomof the insulator (see 5.6).5.5 HoodCircular, sheet-iron, e, from 120 to 130 mm indiameter, the height of the lower perpendicular side to be from50 to 53 mm; provided at the top with a chimney 50 to 60 mmin height and 50 to 56 mm in inside diamete
13、r, which is attachedto the lower part having the perpendicular sides by a cone-shaped member, bringing the total height of the complete hoodto 125 to 130 mm. The hood may be made from a single pieceof metal, providing it conforms to foregoing dimensions. Abridge, g, made of approximately 3 mm iron o
14、r nichrome wire,and having a height of 50 mm above the top of the chimney,shall be attached to handle the chimney when positioning.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.05 on Propertie
15、s of Fuels, Petroleum Coke and Carbon Material.Current edition approved Nov. 1, 2004. Published November 2004. Originallyapproved in 1965. Last previous edition approved in 1999 as D 2416 99.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serv
16、iceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.6 InsulatorCeramic block or refractory ring, f, 150 t
17、o175 mm in diameter if round, or on a side if square, 32 to 38mm in thickness, provided with an inverted cone-shapedopening through the center; 83 mm in diameter at the bottomand 89 mm in diameter at the top.5.7 Vertical Electric Furnace3Bore a hole in the bottomand insert the thermocouple of the py
18、rometer controller so thatits junction is centered exactly 38 mm below the furnaceopening.5.8 Pyrometer Controller4The pyrometer controllershould be checked periodically against a calibrated referencethermocouple, placed alongside but not touching, to ensure thatthe furnace is operating at the desir
19、ed temperature.Appropriatechanges in the controller circuit should be made, when neces-sary, to maintain the required temperature.5.9 SieveU. S. Standard No. 30 (600-m), conforming toSpecification E11.6. Bulk Sampling6.1 Samples from shipments shall be taken in accordancewith Practice D 140, and sha
20、ll be free of foreign substances.Thoroughly mix the sample immediately before removing arepresentative portion for the determination or for dehydration.7. Dehydration of Sample7.1 Hard PitchIf the solid bulk sample contains freewater, air-dry a representative portion.7.2 Soft PitchIf the presence of
21、 water is indicated bysurface foam on 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.7.3 TarDehydrate a represen
22、tative portion of the bulksample in accordance with Test Method D 370, but stop thedistillation when the temperature reaches 170C. Separate anyoil from the water that has distilled over (if crystals are present,warm sufficiently to ensure their solution), and thoroughly mixthe oil with the residual
23、tar in the still after the latter has cooledto a moderate temperature.8. Preparation of Working Sample8.1 Hard PitchIf the pitch can be crushed at roomtemperature, prepare a 20-g working sample by suitablecrushing, mixing, and quartering of a representative portion ofthe dry sample. The crushing can
24、 be done with a small jawcrusher and a mortar and pestle. No particle in the representa-tive sample should be larger than 5 mm in any dimension.Crush this sample so that all of it will pass the No. 30 (600-m)sieve but have a minimum of fine particles.8.2 Soft PitchIf the pitch is too soft to grind a
25、nd to stickyto mix, heat a representative portion of the dry sample to thelowest temperature that will permit passage through the No. 30(600-m) sieve, taking care to avoid excessive loss of volatilematter. Do not exceed 10 min for this melting period. Pass theheated sample through the No. 30 (600-m)
26、 sieve to removeforeign matter.8.3 TarHeat a representative portion of the dry tar rapidlyto the lowest temperature that will permit passage through theNo. 30 (600-m) sieve, then filter through this sieve to removeforeign matter.8.4 Preservation of SamplesStore samples as large lumpsor as solidified
27、 melts in closed containers. Do not save crushedsamples for future analyses since changes in compositionsometimes occur in pulverized pitch.9. Procedure9.1 Ignite a clean porcelain or silica crucible in a mufflefurnace at 900C or over a gas flame for 1 h. Cool in adesiccator and weigh to the nearest
28、 1 mg.9.2 Transfer a 3-g representative portion of the dry tar orpitch to the tared crucible and weigh to the nearest 5 mg. Placethis crucible in the center of the Skidmore crucible. Level thesand in the metal crucible and place the Skidmore crucible inthe exact center. Apply covers to both the Skid
29、more and metalcrucibles, the one on the latter fitting loosely to allow free exitto the vapors as formed.9.3 Place the triangle on the insulator, center the metalcrucible in the insulator with its bottom resting on top of thetriangle, and cover the whole with the sheet-iron hood andchimney in order
30、to distribute the heat uniformly during thecoking process. The assembly, including the insulator ring willbe at approximately room temperature.3The sole source of supply of a Crucible furnace, Hoskins No. FD104, orequivalent, known to the committee at this time is National Element, Inc., 422Oliver S
31、treet, Troy, MI 48084. If you are aware of alternative suppliers, pleaseprovide this information to ASTM International Headquarters. Your comments willreceive careful consideration at a meeting of the responsible technical committee1,which you may attend.4Omega Model D921 Digital Controller with 15
32、amp relay, available fromOmega Engineering, Inc., Stamford, CT; or Thermo Electric Model 700, availablefrom Thermo Electric, Saddle Brook, NJ; or equivalent. Minimum line voltagerequired for 220 V furnace is 205 V. If you are aware of alternative suppliers, pleaseprovide this information to ASTM Int
33、ernational Headquarters. Your comments willreceive careful consideration at a meeting of the responsible technical committee1,which you may attend.FIG. 1 Apparatus for Determining Carbon ResidueD 2416 84 (2004)29.4 Cover the opening of the furnace with the furnace lidand set the controller to mainta
34、in a temperature of 900 6 10C(see 5.8). With the furnace at this temperature, remove the lid,immediately center the assembly (see 9.3) over the furnaceopening and start timing the test period. The positioning of theassembly must be done quickly to avoid excessive loss of heat.Apply heat to the sampl
35、e for exactly 30 min without changingthe setting of the controller. The temperature should recover to900C in 15 min. At the end of 30 min, remove the assemblyfrom the heat source and allow to cool for about 15 min.Remove the porcelain crucible with heated tongs, place in adesiccator, cool, and weigh
36、.10. Calculation10.1 Calculate the coking value of the sample as follows:Coking value, wt. % 5 100A/B (1)where:A = weight of residue, andB = weight of sample.11. Report11.1 Report the coking value to the nearest 0.1 wt %.12. Precision12.1 The following criteria shall be used for judging theacceptabi
37、lity of results (95 % probability):12.1.1 Repeatability Duplicate values by the same opera-tor shall not be considered suspect unless the determinedpercentages differ by more than 1.0.12.1.2 Reproducibility The values reported by each oftwo laboratories, representing the arithmetic average of dupli-
38、cate determinations, shall not be considered suspect unless thereported percentages differ by more than 2.0.13. Keywords13.1 coking value; conradsonASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users
39、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 standard is subject to revision at any time by the responsible technical committee and must be reviewed every fi
40、ve 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 International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical
41、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.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).D 2416 84 (2004)3
