1、Designation: D2416 84 (Reapproved 2015)1Standard Test Method forCoking Value of Tar and Pitch (Modified Conradson)1This standard is issued under the fixed designation D2416; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year
2、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.1NOTESI units formatting was corrected editorially in May 2015.1. Scope1.1 This test method covers the determination of the cok
3、ingvalue of tar and pitch having an ash content not over 0.5 % asdetermined by Test Method D2415.1.2 Coking values by this test method are practically thesame as those obtained by Test Method D189, but results aremore reproducible. The apparatus used is identical, except thatan electric furnace is s
4、ubstituted for the gas flame.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 purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of th
5、is 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:2D140 Practice for Sampling Bituminous MaterialsD189 Test Method for Conradson Carbon Residue of Petro-leum ProductsD370
6、 Practice for Dehydration of Oil-Type PreservativesD2415 Test Method for Ash in Coal Tar and PitchE11 Specification for Woven Wire Test Sieve Cloth and TestSieves3. Summary of Test Method3.1 A sample of the tar or pitch is vaporized and pyrolizedfor a specified time at a specified temperature in spe
7、cialstandardized equipment that limits the available oxygen sup-ply. The percentage of residue is reported as the coking value.4. Significance and Use4.1 This test method is useful for indicating the relativecoke-forming propensities and for evaluating and characteriz-ing tars and pitches. This test
8、 method can also be used as oneelement in establishing the uniformity of shipments or sourcesof supply.5. Apparatus (see Fig. 1)5.1 CrucibleWide-form, a, either porcelain, glazedthroughout, or silica, a; 29 mL to 31 mL capacity, 46 mm to49 mm in rim diameter.5.2 Skidmore CrucibleIron crucible, b, fl
9、anged andringed, 65 mL to 82 mL capacity, 53 mm to 57 mm inside and60 mm to 67 mm outside diameter of flange, 37 mm to 39 mmin height, supplied with a cover without delivery tubes andhaving the vertical opening closed. The horizontal opening ofabout 6.5 mm shall be kept clean. The outside diameter o
10、f theflat bottom shall be 30 mm to 32 mm.5.3 Metal CrucibleSpun sheet-iron or nickel crucible, c,with cover; 78 mm to 82 mm in outside diameter at the top,58 mm to 60 mm in height, and approximately 0.8 mm inthickness. At the bottom of this crucible, and level before eachtest, shall be a layer of ab
11、out 25 mL of sand, or enough to bringthe Skidmore crucible, with cover on, nearly to the top of thesheet-iron crucible. The sand shall be dry and screened to passthrough a 65-mesh screen and to be retained on a 200-meshscreen.5.4 Wire SupportTriangle (65 mm) of bare Nichrome wire1.5 mm to 2.0 mm in
12、cross section, having an opening smallenough to support the bottom of the metal crucible (see 5.3).The triangle, d, shall have its arms bent to form a cradle thatwill support the metal crucible with its bottom level with thebottom of the insulator (see 5.6).5.5 HoodCircular, sheet-iron, e, from 120
13、mm to 130 mmin diameter, the height of the lower perpendicular side to befrom 50 mm to 53 mm; provided at the top with a chimney50 mm to 60 mm in height and 50 mm to 56 mm in insidediameter, which is attached to the lower part having theperpendicular sides by a cone-shaped member, bringing thetotal
14、height of the complete hood to 125 mm to 130 mm. The1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.05 on Properties of Fuels, Petroleum Coke and Carbon Material.Current edition a
15、pproved April 1, 2015. Published May 2015. Originallyapproved in 1965. Last previous edition approved in 2009 as D2416 84 (2009).DOI: 10.1520/D2416-84R15E01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of AS
16、TMStandards 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 States1hood may be made from a single piece of metal, providing itconforms to foregoing dimension
17、s. A bridge, g, made ofapproximately 3 mm iron or nichrome wire, and having aheight of 50 mm above the top of the chimney, shall beattached to handle the chimney when positioning.5.6 InsulatorCeramic block or refractory ring, f, 150 mmto 175 mm in diameter if round, or on a side if square, 32 mmto 3
18、8 mm 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 pyrometer controller so thatits junction is centered exactly 3
19、8 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 desired temperature.Appropriatechanges in the controller circuit
20、should be made, whennecessary, 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 D140, and shall be free of foreign substances.Thoroughly mix the sample imme
21、diately 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 water is indicated bysurface foam on heating, maintain a repre
22、sentative portion ofthe bulk sample at a temperature between 125 C and 150 C inan open container until the surface is free from foam. Take carenot to overheat, and remove heat source immediately whenfoam subsides.7.3 TarDehydrate a representative portion of the bulksample in accordance with Test Met
23、hod D370, but stop thedistillation when the temperature reaches 170 C. 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 tar in the still after the latter has cooledto a moderate te
24、mperature.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 be done with a small jawcrusher and a mortar and pestle. No
25、 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 and to stickyto mix, heat a representative portion of the dry
26、 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) sieve to removeforeign matter.8.3 TarHeat a representative
27、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 melts in closed containers. Do not save crushedsamples for
28、future analyses since changes in compositionsometimes occur in pulverized pitch.9. Procedure9.1 Ignite a clean porcelain or silica crucible in a mufflefurnace at 900 C or over a gas flame for 1 h. Cool in adesiccator and weigh to the nearest 1 mg.9.2 Transfer a 3 g representative portion of the dry
29、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 in3The sole source of supply of a Crucible furnace, Hoskins No. FD104, orequivalent, known to the committee
30、at this time is National Element, Inc., 422Oliver Street, 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 committee,1which you may a
31、ttend.4Omega Model D921 Digital Controller with 15 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 su
32、ppliers, pleaseprovide this information to ASTM International Headquarters. Your comments willreceive careful consideration at a meeting of the responsible technical committee,1which you may attend.FIG. 1 Apparatus for Determining Carbon ResidueD2416 84 (2015)12the exact center. Apply covers to both
33、 the Skidmore 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
34、in order to distribute the heat uniformly during thecoking process. The assembly, including the insulator ring willbe at approximately room temperature.9.4 Cover the opening of the furnace with the furnace lidand set the controller to maintain a temperature of 900 C 610 C (see 5.8). With the furnace
35、 at this temperature, removethe lid, immediately center the assembly (see 9.3) over thefurnace opening and start timing the test period. The position-ing of the assembly must be done quickly to avoid excessiveloss of heat. Apply heat to the sample for exactly 30 minwithout changing the setting of th
36、e controller. The temperatureshould recover to 900 C in 15 min. At the end of 30 min,remove the assembly from the heat source and allow to cool forabout 15 min. Remove the porcelain crucible with heatedtongs, place in a desiccator, cool, and weigh.10. Calculation10.1 Calculate the coking value of th
37、e sample as follows:Coking value, mass percent 5 100 A/B (1)where:A = mass of residue, andB = mass of sample.11. Report11.1 Report the coking value to the nearest 0.1 masspercent.12. Precision12.1 The following criteria shall be used for judging theacceptability of results (95 % probability):12.1.1
38、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 ReproducibilityThe values reported by each of twolaboratories, representing the arithmetic average of duplicatedeterminations, shall not be considered
39、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 of this standard are expressly advised that d
40、etermination 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 five years andif not revised, either reapproved
41、 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 committee, which you may attend. If you feel
42、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 reprin
43、ts (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 Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 84 (2015)13
