Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
  • C25C3/00—Electrolytic production, recovery or refining of metals by electrolysis of melts
  • C25C3/06—Electrolytic production, recovery or refining of metals by electrolysis of melts of aluminium
  • C25C3/08—Cell construction, e.g. bottoms, walls, cathodes
  • C25C3/12—Anodes
  • C25C3/125—Anodes based on carbon
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
  • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
  • C25B11/042—Electrodes formed of a single material
  • C25B11/043—Carbon, e.g. diamond or graphene
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
  • C04B35/52—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbon, e.g. graphite
  • C04B35/528—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbon, e.g. graphite obtained from carbonaceous particles with or without other non-organic components
  • C04B35/532—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbon, e.g. graphite obtained from carbonaceous particles with or without other non-organic components containing a carbonisable binder
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10C—WORKING-UP PITCH, ASPHALT, BITUMEN, TAR; PYROLIGNEOUS ACID
  • C10C3/00—Working-up pitch, asphalt, bitumen
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10C—WORKING-UP PITCH, ASPHALT, BITUMEN, TAR; PYROLIGNEOUS ACID
  • C10C3/00—Working-up pitch, asphalt, bitumen
  • C10C3/002—Working-up pitch, asphalt, bitumen by thermal means
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G19/00—Refining hydrocarbon oils in the absence of hydrogen, by alkaline treatment
  • C10G19/067—Refining hydrocarbon oils in the absence of hydrogen, by alkaline treatment with molten alkaline material
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
  • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
  • C25B11/042—Electrodes formed of a single material
  • C25B11/043—Carbon, e.g. diamond or graphene
  • C25B11/044—Impregnation of carbon

Definitions

• This invention relates to a process of producing oarbonaceous materials useful as binders for carbon electrodes and to a composition useful as a binder for carbon electrodes.
• Coal tar pitch is almost universally used as a binder in the manufacture of amorphous and graphitized electrodes, blocks, cylinders, powders and other carbon prodn ucts.
• the pitch is mixed with powdered or granular petroleum coke or similar material and the mixture is pressed, extruded or molded to obtain the desired shapes before baking.
• Coal tar pitch is especially suitable because it contains a high content of benzene insoluble resinous materials which yield coke when carbonized at relatively low temperatures. The formation of this coke between the grains of solid carbonaceous materials comprising the bulk of the structure cements the latter together into a dense and highly conductive product.
• a carbon electrode pitch binder is preferably made in two stages from a particular petroleum residue.
• the petroleum residue is an aromatic tar obtained by steam cracking gas oil.
• the residue is the bottoms fraction taken from the fractionator used for fractionating steam cracked products.
• the first stage of the invention includes preparing a high softening point, relatively insoluhie base material of high coking value by a suitable heat treating process, preferably destructive distillation or heat soaking, and the second stage includes fluxing this base material with a minor proportion of a lighter or lower boiling hydrocarbon fraction to the softening point desired when using destructive distillation, and flashing when using heat soaking under superatmospheric pressure.
• the two stages can be carried out in one apparatus.
• the first stage may be an air oxidation process instead of the preferred processes named but is not considered a full equivalent of the preferred processes.
• the aromatic tar has a high asphaltene content between about 12 and 25 wt. percent.
• Quinoline insoluble material is low for the binders or pitches made from aromatic tars according to the present invention, usually about 2 wt. percent and this is a good feature or characteristic.
• Quinoline soluble material in the binder is fusible and capable of great binding strength on solidification. The quinoline soluble material is considered to be much superior to the quinoline insoluble material.
• Wlrere the heat treating step is maintained under superatmospheric pressure, such as visbreaking or heat soaking, condensation and polymerization of some of the light material occurs because of the longer contact time.
• superatmospheric pressure such as visbreaking or heat soaking, condensation and polymerization of some of the light material occurs because of the longer contact time.
• heat soak ing plus flashing is the preferred method of carrying out the process.
• Moderate pressure between about 50 and 1500 p.s.i.g. may be used.
• a thermal cracking coil having a soaking drum can be used for heat soaking the heated aromatic tar feed.
• the products from heat soaking under. pressure are flashed to recover bottoms from light overhead products. Sufiicient of the light material is removed to give a bottoms product of the desired softening point for a petroleum pitch binder.
• thermocouples vapor and pot temperatures
• mercury sealed stirrer a distillate outlet
• flux arm which replaced one of the thermocouples during the fluxing operation which should be done isothermally.
• the vapor temperature in the still was maintained between about 525 F. and 710 F. and the pot temperature was maintained between about 650 F. and 850 F. Heat was supplied by gas heating.
• the destructive distillation proceeded at a rate of about 5-30 ml. minute and for about 25 to 60 minutes until the desired bottoms product was obtained. This was controlled by the percentage of overhead product taken.
• the required amount of flux oil which in this case was part of the feed aromatic tar was then added through the flux arm and the heating and stirring continued for about fifteen minutes. The heating mantle around the top of, the still was removed just prior to fluxing to prevent the removal of additional overhead.
• the flux liquid may be;
• the still was provided with a leak
• about 72.8 parts by weight of the residue in Table 1 were mixed with 27.2 parts by weight of flux (aromatic tar feed) and heat soaked at a temperature of about 800 F. for about 15 minutes.
• the resulting pitch had a softening point of about 218 F., benzene insoluble of 26.4 wt. percent and a coking value of about 52.7 wt. percent.
• the weight percent residue was about 37.6. 78.4 parts by weight of this residue were heat soaked 15 minutes at a temperature of about 800 F. After adding about 21.6 parts by weight of flux oil, the resulting pitch having a softening point of about 235 F., benzene insoluble of about 32.3 wt. percent and a coking value ofabout 54.5 weight percent.
• the actual distillation rate does not seem critical. But the end point is critical.
• the weight percent residue was 27.9 and using 37.3 Weight percent of quench oil the residue could not be blended to give a homogeneous product.
• the pot temperature was about 844 F. and the time of distilling was about 30 minutes
• the wt. percent residue was 31.2 and was blended into a pitch binder when using 36 wt. percent quench oil.
• the pitch product had a softening point of about 252 F., benzene insoluble about 32.5 wt. percent and a coking value of about 55 WtLpercent.
• Coking value of the product is the residue in Wt. percent not volatilized obtained after putting a sample in a crucible and heating to about 1022 F. for about 2% hours.
• the flux used was a portion of the aromatic tar feed. Stirring was used throughout the entire operation. Less than about 70 wt. percent of the aromatic tar should be removed overhead during destructive distillation as it has been found that when more than about 70 wt. percent of the aromatic tar is taken overhead during the destructive distillation step it is not possible to successfully flux or blend back the residue with a liquid to give a homogeneous product and satisfactory binder.
• the following data in Table 2 were obtained by destructive distillation of the aromatic (tar feed at temperatures between about 525 F. and 710 F. vapor temperature or 650850 F. pot temperature to the wt. percent residues based on the aromatic tar starting product. The times of heating were from about 30 minutes to 60 minutes.
• the data also include the fiuxed compositions comprising the residues obtained on distillation fluxed with the aromatic tar feed or starting product.
• the inspeotions show that the composition blends closely simulate accepted specifications for coal tar pitch used as an electrode binder.
• the overall yield of electrode binder pitch based on the aromatic tar feed was about 43.3 wt. percent.
• percent Pitch binders made from heat treated aromatic tars according to the present invention have the characteristics given in Table 3.
• the binder in Column B was used to make an electrode.
• the calcined petroleum coke is screened and various fractions of particle sizes are used.
• a general method of making and testing compressive strength of test electrodes, etc. is given in A Laboratory Evaluation of Pitch Binders Using Compressive Strength of Test Electrodes, by H. L. Jones et al., Journal of Chemical and Engineering Data, vol. 5, No. 1, January 1960, pages 8487. This publication on page 84 gives a typical particle size distribution.
• the course fraction of the calcined coke which may be a petroleum coke is mixed with the heated binder and then the other finer fractions of coke are added. The mixture is molded under pressure and heated to about 1832 F.
• the heating at 1832 F. being only for about one hour to carbonizc or coke the binder.
• One electrode was made using the binder of Column B and it met the minimum compressive strength and electrical resistivity requirements. Other methods of making electrodes may be used.
• the pitch binder can also be made according to the present invention by heat treating at a temperature in the range of about 800 F. to 900 F. for about 5 minutes to 150 minutes or longer and such treating is preferably heat soaking under a pressure between about 30 p.s.i.g. and about 2000 p.s.i.g.
• the heat soaked products are then flashed to a lower pressure zone to recover a bottoms fraction suitable for use as a pitch binder.
• a temperature in the range of about 800 F. to 900 F. for about 5 minutes to 150 minutes or longer and such treating is preferably heat soaking under a pressure between about 30 p.s.i.g. and about 2000 p.s.i.g.
• the heat soaked products are then flashed to a lower pressure zone to recover a bottoms fraction suitable for use as a pitch binder.
• In an atmospheric pressure process while it is not necessary to blend back or flux, as the distillation or heat treatment may be stopped when the desired amount of lower boiling material is removed overhead from the
• the benzene insoluble was about 7% by weight, whereas in those experiments where 22 to 31 wt. percent flux or quench was used the benzene insolubles were about 28 to 35 wt. percent.
• Heat soaking runs were carried out under pressure at 780 F. to 860 F. The times of heating were between about minutes and about minutes when the temperature was above 700 F. At 780 F. there was only mild cracking at 100 p.s.i.g. maximum pressure. At 85 0 F. maximum temperature, cracking was more severe, resulting in 1100 psig maximum pressure and about 14 wt. percent benzene insolubles. Asphaltene content and coking value also increased with. increasing severity.
• Heat soaking aromatic tar feed under pressure and flashing are believed to be the best means of preparing electrode pitch binders as the yields of high coking value material are much greater than the other methods invc-stigated.
• a composition for use as a binder for carbon electrodes including a high boiling high molecular Weight hydrocarbon residue produced by heating a residual aromatic tar having an API gravity of about l.6 to 4.0 and an asphaltene content between about 12 and 25 Wt. percent,
• a pitch binder for carbon electrodes made solely from residual aromatic tar from high temperature cracking of gas oil as defined in claim 1 which has a softening point of between about 175 and 230 F., a coking value between about 50 and 57 wt. percent and benzene insoll5 uble material between about 15 and 40 Wt. perecnt.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Materials Engineering (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• General Chemical & Material Sciences (AREA)
• Structural Engineering (AREA)
• Metallurgy (AREA)
• Electrochemistry (AREA)
• Ceramic Engineering (AREA)
• Civil Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Working-Up Tar And Pitch (AREA)
• Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)

Priority Applications (8)

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Cited By (12)

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Citations (10)

• 0
  • NL NL267528D patent/NL267528A/xx unknown
• 1960
  • 1960-07-26 US US45295A patent/US3173851A/en not_active Expired - Lifetime
• 1961
  • 1961-06-06 GB GB20401/61A patent/GB913730A/en not_active Expired
  • 1961-07-11 GB GB25072/61A patent/GB938301A/en not_active Expired
  • 1961-07-18 SE SE741161A patent/SE185308C1/sv unknown
  • 1961-07-25 DK DK304261AA patent/DK108462C/da active
  • 1961-07-25 DE DEE21421A patent/DE1258532B/de active Pending

Patent Citations (10)

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