Classifications

• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F9/00—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments
  • D01F9/08—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments of inorganic material
  • D01F9/12—Carbon filaments; Apparatus specially adapted for the manufacture thereof
  • D01F9/14—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F9/00—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments
  • D01F9/08—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments of inorganic material
  • D01F9/12—Carbon filaments; Apparatus specially adapted for the manufacture thereof
  • D01F9/14—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments
  • D01F9/145—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from pitch or distillation residues
  • D01F9/15—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from pitch or distillation residues from coal pitch

Definitions

• the invention relates to a process for producing anisotropic carbon fibers from coal tar pitch, in particular hard coal tar pitch, according to which the coal tar pitch is freed of infusible components by filtration prior to spinning, then the pitch filtrate is distilled in a thin-film evaporator to remove volatile components, then those obtained Pitch fibers spun pitch melt are oxidized at a predetermined oxidation temperature and carbonized at a predetermined carbonization temperature.
• the invention comprises the production of anisotropic carbon filaments.
• Coal tar pitch is spun from the melt and the pitch fibers obtained are subjected to oxidation, then carbonization and optionally graphitization.
• the coal tar pitch has a softening point of at most 190 ° C (KS or Krämer-Sarnow) and is heated to a temperature up to 100 ° C above the softening point before spinning. At this temperature, the pitch melt obtained is essentially freed from the solid constituents by filtration under elevated pressure.
• the solid or infusible components are identical to components insoluble in quinoline.
• the filtered pitch melt is either distilled to Subjected to 350 ° C or after cooling to small pitch, which are brought into contact with an aliphatic solvent with a boiling point of up to 70 ° C.
• the solvent with the pitch constituents dissolved therein is separated from the insoluble pitch constituents.
• the carbon fibers spun from the pitch melt are dusted with finely ground activated carbon, which is impregnated with liquid oxidizing agents, and heated to 400 ° C. in an oxidizing atmosphere.
• the subsequent carbonization of the oxidized carbon fibers takes place at a temperature of approximately 1000 ° C. (cf. DE-PS 24 19 659).
• the invention is based on the object of specifying a process for producing anisotropic carbon fibers from coal tar pitch, in particular coal tar pitch, of the type described at the outset, according to which short treatment or residence times during the thermal conversion and aftertreatment as well as high throughputs and low energy and inert gas consumption can be achieved, so that the anisotropic carbon fibers can be produced efficiently and economically.
• the invention achieves this object in a generic method in that the pitch filtrate or its toluene-soluble portion is concentrated in the thin-film evaporator to form a mesophase-forming pitch filtration, and the pitch concentrate obtained is converted to a mesophase pitch in the course of a thermal treatment, and in that the mesophase pitch is spun by means of a spinning centrifuge, if necessary under increased initial pressure, and that the carbon fibers are further graphitized after carbonization.
• the use of a thin-film evaporator first of all substantially simplifies the process by removing the volatile pitch constituents on the one hand and the concentration of the mesophase-forming pitch fraction on the other.
• the degassing of the mesophase deposits is simplified and the thermal treatment times are shortened.
• a higher carbon fiber yield is achieved because the spun pitch fibers have a high C content. Atmospheric oxygen is sufficient as the oxidizing agent for the oxidation process.
• no fiber bonds occur during the thermal aftertreatment.
• the thermal conversion into mesophase pitch is simplified, a mesophase with anisotropy running over a large area being achieved.
• a higher yield, less exhaust gas development and shorter residence times during the thermal conversion are guaranteed.
• the compounds present in coal tar pitch are soluble in various organic solvents, e.g. B. hexane, toluene and quinoline classified.
• the quinoline-insoluble compounds represent the high molecular weight fraction
• the toluene-insoluble compounds the medium molecular weight fraction.
• the part which is insoluble in toluene has proven to be particularly suitable for producing a mesophase.
• the quinoline-insoluble substances present in the raw pitch can be removed quantitatively by known filtration processes. It is difficult to separate off the toluene-soluble fraction since, in the known processes, undesired substances with higher molecular weights are formed due to the residence times and temperatures used.
• the concentration of the toluene-insoluble fraction takes place in a thin-film evaporator without the re-formation of quinoline-insoluble substances, preferably at dwell times of less than one minute, temperatures above 200 ° C. and vacuum to 1 mbar.
• a thin-film evaporator without the re-formation of quinoline-insoluble substances, preferably at dwell times of less than one minute, temperatures above 200 ° C. and vacuum to 1 mbar.
• the concentrate obtained is an excellent mesophase former and can be converted, for example, after thermal treatment at temperatures from 400 ° C. to 500 ° C., preferably 450 ° C. Compared to known processes, however, this conversion can be achieved in significantly shorter dwell times. In addition, the conversion takes place almost quantitatively with corresponding dwell times.
• a treatment temperature of 450 ° C starting from concentrate II, a light-optically determined mesophase content of 60% can be achieved after only 30 minutes, which increases to over 75% after a further 30 minutes.
• a centrifugal spinning machine is particularly suitable for spinning and orienting the mesophase pitch, the high viscosity of the spinning melt being taken into account, if appropriate, by the combination of centrifugal forces and increased form.
• the process according to the invention enables the anisotropic carbon fibers to be produced economically by means of the shortest residence times, which is synonymous with high throughputs and low investment costs.
• a device for storage and thermal treatment which uses the retort technique and, in addition to short residence times and consequently reduced investment costs, low energy - and inert gas consumption guaranteed.
• it is a device with at least
• an upper revolving stage which can be rotated independently of the lower revolving stage and has a traversing device for treatment retorts for temporarily receiving the fiber deposit with the pitch fibers to be treated,
• Retort lid holder for retort lid with connection for air and inert gas supply, vacuum and exhaust air,
• the traversing device for the treatment retorts for connection to the respective retort lid is transferred from the upper rotating platform under the relevant retort lid and vice versa, and wherein the lower rotating platform has at least one lifting device for each of the oxidation oven which has the vacuum retort, the carbonization oven and the cooling retort and these treatment devices for accommodating the treatment retorts can be moved and raised under the retort lid receptacle or the relevant retort lid and vice versa.
• This device which is now used more for the production of anisotropic carbon fibers, is characterized in that the lower revolving stage is equipped with a second vacuum retort and a graphitization furnace as a further treatment device in an open design.
• the device according to the invention one of the six processes of oxidation, evacuation, carbonization, evacuation, graphitization and cooling can take place under each retort lid.
• FIG. 2 shows the device for thermal aftertreatment in a schematic top view below the loading level
• the coal tar pitch is freed of infusible or quinoline-insoluble constituents by filtration prior to spinning. Then the pitch filtrate subjected to a distillation to remove volatile or low molecular weight constituents. Then, the pitch fibers 2 spun from the pitch melt obtained, using powdered substances introduced or applied, at a predetermined oxidation temperature
• the oxidized pitch fibers 2 are carbonized using an inert gas at a predetermined carbonization temperature.
• the pitch filtrate is continuously introduced into a thin-film evaporator in the course of the distillation and is evenly distributed over the inner circumference by means of a rotating distributor ring.
• the rotor wiper blades moving along the evaporator zone capture the pitch filtrate and spread a thin film over the heating wall.
• the volatile product portion evaporates under the influence of an applied vacuum and is deposited on a condenser.
• the non-evaporated product portion namely a mesophase-forming pitch fraction, leaves the thin-film evaporator and is converted to a mesophase pitch by means of a thermal treatment.
• the mesophase pitch is granulated. None of this is shown.
• the mesophase pitch granules are melted in an extruder 3.
• the pitch melt runs through a filter 4 and is fed to a centrifugal spinning head 6 by means of a metering pump 5.
• the spinning centrifuge which is provided with nozzle holes on its lower part, presses the pitch melt due to centrifugal forces and an additional pressure support through the nozzle holes. Endless filaments are created, which are placed on a slowly rotating catch ring.
• the catch ring is provided with a cutting device which cuts the continuous filaments to the desired fiber length. Since you want to have a fuse for the subsequent thermal aftertreatment, you will need a fuse Number of individual fibers, which result in the desired sliver cross-section, are placed one above the other on the catch ring.
• the sliver deposit takes place in a coiler 7.
• the fiber sliver is deposited over deflection rollers 8 in free-hanging loops on an extended scissor gate 9.
• the scissors gate 9 is pushed together in order to ensure a high space utilization of the oxidation furnace 10 or carbonization furnace 11 and is placed in a treatment retort 12.
• a first vacuum retort 13 is located in the basement and the oxidation furnace 10 is moved over the treatment retort from below
• the treatment retort 12 driven.
• the treatment retort 12 is heated up according to a graduated temperature program. During this oxidation process to make the pitch fibers 2 infusible, hot oxidation air flows through the treatment retort 12 from bottom to top.
• the subsequent carbonization process must be carried out under inert gas in order to avoid burning the pitch fibers 2.
• the treatment retort 12 is first evacuated. Since the treatment retort 12 is made of non-vacuum-proof thin sheet for the purpose of good heat transfer, the carbonization furnace 11 is moved down and heated to 1000 ° C. while the vacuum retort
• the vacuum retort 13 is lifted from the basement under the treatment retort 12.
• a vacuum unit is then put into operation. After a few minutes, the vacuum retort 13 or treatment retort 12 can be expanded to normal pressure with nitrogen. For safety reasons, it is flushed again with nitrogen. Then the vacuum retort 13 is lowered back into the basement and against the car heated up to 1000 ° C Rating furnace 11 replaced.
• the carbonization requires a ten minute residence time, volatile compounds being transported through preheated nitrogen via the treatment retort 12 for condensation or exhaust air combustion. After the carbonization has ended, the carbonization furnace 11 is moved down and a further vacuum retort 13a is lifted from below over the treatment retort 12.
• the treatment retort 12 is flushed with argon while relieving pressure.
• a graphitization furnace 14 heated to 2800 ° C. is moved over the treatment retort 12.
• preheated argon is passed through the treatment retort 12 and transports the volatile compounds to the exhaust system.
• the carbon fibers 1 are cooled to temperatures below 600 ° C. by supplying cold argon or nitrogen. Further cooling can take place in a cooling retort 15 with cold air.
• the device for the thermal aftertreatment of the pitch fibers 2 has a lower rotating stage 16 with the oxidation furnace 10, the vacuum retorts 13, 13a, the carbonization furnace 11, the graphitization furnace 14 and the cooling retort 15. All treatment devices 10 to 15 are designed in an open container construction for receiving treatment retorts 12. Furthermore, an upper rotary stage 17 which can be rotated independently of the lower rotary stage 16 and has a traversing device for treatment retorts 12 for the temporary reception of the
• Fiber trays 9 provided with the pitch fibers 2 to be treated.
• a loading level 18 with at least one loading opening 19 and at least one retort lid holder 20 for Cake lid 21 with connection for air and inert gas supply, vacuum and exhaust air.
• the traversing device guides the treatment retorts 12 for connection to the respective retort cover 21 from the upper rotating platform 17 under the relevant retort cover 21 and vice versa.
• the lower rotating stage 16 has at least one lifting device 22 for each of the oxidation furnace 10, the vacuum retorts 13, 13a, the carbonization furnace 11, the graphization furnace 14 and the cooling retort 15.
• These treatment devices 10 to 15 can be moved and raised to receive the treatment retorts 12 under the retort lid receptacles 20 or the relevant retort lid 21 or vice versa.
• the treatment devices 10 to 15 can be displaced by 60 ° to one another on the lower rotating platform 16 and are arranged on a rotating circle which, in vertical projection, exceeds the outer circumference of the upper rotating platform 17 for passing the treatment devices 10 to 15 to be raised and for Connection of the raised treatment devices 10 to 15 to the respective retort lid 21 extends below the retort lid receptacles 20, which are offset by 60 ° in relation to one another.
• Each treatment device 10 to 15 is assigned its own lifting device 22, so that one of the six processes of oxidation, evacuation, carbonization, evacuation, graphitization and cooling can take place simultaneously under each retort lid 21.
• the fiber tray is designed as a collapsible scissors gate 9 for fiber loops hanging freely on horizontal bars and, when pushed together, can be inserted into a treatment retort 12 in each case. - 12 -
• the device operates as follows if one of the six processes of oxidation, evacuation, carbonization, evacuation, graphitization and cooling takes place simultaneously under each retort lid 21:
• Fig. 4 The upper revolving stage 17 rotates through 180 °. While a scissors gate 9 with finished anisotropic carbon fibers 1 is removed from the other treatment retort 12, the lower rotating stage rotates by 60 °, so that the cooling retort 15 is exchanged for the oxidation furnace 10.
• the lifting device 22 moves the oxidation furnace 10 - a low-temperature furnace - from below over the treatment retort 12.
• hot oxidation air is passed through the treatment retort 12 and the oxidation furnace 10 is heated up in accordance with the optimized temperature profile.
• the hot process gases are fed to the exhaust air cleaning system.
• Fig. 7 After oxidation has ended, the oxidation furnace 10 is moved down to the lower rotating platform 16.
• Fig. 8 The lower rotating stage 16 rotates by 60 °, so that the first vacuum retort 13 comes under the treatment retort 12 Z.
• 9 The vacuum retort 13 is lifted from below over the treatment retort 12 by means of the hydraulic lifting device 22. The vacuum applied evacuates the furnace.
• Fig. 10 For safety, the treatment retort 12 is still flushed with nitrogen while relieving pressure. The vacuum retort 13 is moved down to the lower rotating platform.
• Fig. 11 The lower rotating stage rotates by 60 °, so that the now 1000 ° C hot carbonization furnace 11 - a high temperature furnace - is under the treatment retort 12.
• Fig. 12 The carbonization furnace 11 is moved from below over the treatment retort 12 by means of the hydraulic lifting device. During the subsequent carbonation process, preheated nitrogen is passed through the treatment retort 12 and transports the volatile compounds to the exhaust system.
• Fig. 13 The carbonization furnace 11 is moved down to the lower rotating platform 16.
• the lower rotating stage 16 rotates by 60 °, so that the further vacuum retort 13a comes to rest under the treatment retort 12.
• Fig. 15 The vacuum retort 13a is via the hydraulic
• Fig. 16 For safety, the treatment retort 12 is flushed with argon while relieving pressure. The vacuum retort 13a is moved down to the lower rotating stage 16.
• Fig. 17 The lower rotating stage 16 rotates by 60 °, so that the 2800 ° C hot graphitization furnace 14 is under the treatment retort 12.
• the graphitization furnace 14 is moved from below over the treatment retort 12 via the hydraulic lifting device 22. During the subsequent graphitization process, preheated argon is passed through the treatment retort 12 and transports the volatile compounds to the exhaust system.
• Fig. 19 The graphitization furnace 14 is brought down to the lower rotating stage 16.
• Fig. 20 The lower rotating stage 16 rotates by 60 °, so that the cooling retort 15 comes to rest under the treatment retort 12.
• the carbon fibers 1 are cooled to temperatures below 600 ° C. by supplying cold argon or nitrogen.
• Fig. 21 Further cooling can take place in the cooling retort 15 with cold air.
• Fig. 22 The cooling retort 15 is moved down to the lower rotating platform 16.
• the retort 12 is transported to the upper rotary stage 17 by the traversing device. A new cycle begins.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Inorganic Fibers (AREA)
• Working-Up Tar And Pitch (AREA)

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Publications (1)

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• 1987
  • 1987-07-21 DE DE19873724102 patent/DE3724102C1/de not_active Expired
• 1988
  • 1988-01-06 AU AU12404/88A patent/AU1240488A/en not_active Abandoned
  • 1988-01-06 WO PCT/EP1988/000006 patent/WO1989000618A2/de not_active Application Discontinuation
  • 1988-01-06 EP EP19880901236 patent/EP0326587A1/de not_active Withdrawn
  • 1988-01-15 IN IN38/CAL/88A patent/IN168633B/en unknown
  • 1988-02-05 GR GR880100059A patent/GR880100059A/el unknown
  • 1988-03-17 DD DD31375388A patent/DD280982A5/de not_active IP Right Cessation
  • 1988-03-21 CN CN 88101454 patent/CN1030799A/zh active Pending
  • 1988-03-22 ES ES8800867A patent/ES2006118A6/es not_active Expired

Non-Patent Citations (1)

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