JP2006076801A - Carbonization type graphite production method from raw material of waste tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive and high-yield carbonization type graphite production method capable of treating a waste tire in whole and sintering the contained carbon component, thereby recyclably and inexpensively producing graphite in a high yield. <P>SOLUTION: The waste tire is heated at high temperature under a non-oxygen state within a heat-resisting furnace as it is without being broken. Thus, the tire is thermally decomposed, and is separated into mixed gas components to be vaporized and mixed solid components remaining in the furnace without being vaporized. Thereafter, flame is projected on the remaining mixed solid components with a burner, so as to burn away inflammable solid components. Next, lightweight ash components and metal components are separated away from nonflammable components remaining in the furnace, and the remaining carbon component is sintered. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing dry distillation graphite using a waste tire as a raw material, and more specifically, a waste tire that is difficult to treat as waste (for example, an old tire, a defective tire, etc.) as a raw material, and is contained in a large amount in the waste tire. The present invention relates to a rational utilization method of industrial waste that can reuse carbon components as high-quality graphite.

  As is well known, unnecessary tires such as old tires contain a high concentration of carbon, which is a useful component. For example, in the case of steel radial tires for trucks and buses, 15 to 25 wt%, Steel radial tires for light trucks contain 20-30 wt%, and passenger car radial tires contain 20-30 wt% (according to Japan Waste Tire Recycling Cooperative Association: http: // www.j-sra.jp/materials/).

Therefore, as a proposal to take out useful components such as graphite and flammable gas from unnecessary tires and reuse them, “Waste tire decomposition processing method and apparatus” disclosed in Japanese Patent Application Laid-Open No. 2003-211140 It has been known. The known technique proposed here breaks up the waste tires into small pieces, and directly immerses these pieces in the molten salt in the molten salt decomposition tank and thermally decomposes them at a temperature higher than the melting temperature in an inert gas atmosphere. A combustible gas is recovered from a gas component generated by thermal decomposition through a cold wrap or a filter, and carbon is recovered from a molten salt in a water washing tank (refer to Patent Document 1 = hereinafter referred to as “known method”). .
JP 2003-211140 (see paragraphs [0011] to [0015]) However, in the above known method for taking out useful components from waste tires (waste tires), the tires must be crushed into small pieces. In addition, since a large amount of lithium chloride or potassium chloride is used, the burden of running costs increases, and in addition, the gas components generated during the treatment process include cold traps and filters that consist of several stages of traps. There is a drawback that a large amount of fixed costs and a lot of processing time are required because of having to go through.

  The present invention has been made in view of the above-mentioned problems in the above-described known method for extracting useful components from unnecessary tires for recycling, and treating unnecessary tires as they are. It is an object of the present invention to provide a low-cost and high-yield method that can sinter the contained carbon component and can be recycled as graphite.

  Another object of the present invention is to provide a dry distillation type graphite production method capable of producing graphite from waste tires with high efficiency basically only by heat treatment.

  Furthermore, if necessary, the present invention relates to dry distillation graphite made from waste tires that can be reused as fuel gas by removing toxic sulfur components from the mixed gas produced as a by-product in the process of pyrolyzing the waste tires. A secondary object is to provide a manufacturing method.

  Thus, the means adopted by the present invention to solve the above technical problem is basically high-temperature heating in an oxygen-free state in a heat-resistant furnace in the shape of a tire without crushing unnecessary tires. By separating the component constituting the tire into a mixed gas component that is thermally decomposed and vaporized and a mixed solid component that remains in the furnace without being vaporized, the mixed solid component that remains without being vaporized is transferred from the burner to the flame. To burn off the combustible solid component, then separate and remove the light ash component and metal component from the non-combustible component left in the furnace without burning, and sinter the remaining carbon component It is characterized by obtaining graphite.

  The present invention also proposes a method of sequentially using a plurality of furnaces in order to solve the above technical problem, and the configuration thereof is as follows.

  That is, the present invention provides a mixed gas component and a mixed solid component by heating in an oxygen-free state at a temperature of about 1300 to 1500 ° C. in a heat-resistant primary furnace in the shape of a tire without crushing unnecessary tires. Then, the mixed solid component is transferred into a heat-resistant secondary furnace, a flame is emitted from a burner to burn and remove the combustible solid component, and the non-combustible remaining in the secondary furnace is removed. After removing the ash component and the metal component from the solid component, the remaining carbon component is filled in a mold, accommodated in an electric furnace, and sintered and taken out as graphite.

  In the above invention method, the separated mixed solid component is cooled to a liquidus temperature below the ignition point of the tire rubber component by bringing it into contact with the outside air, and the mixed solid component is settled and separated by specific gravity. A process is employed in which a flame is emitted from the burner to the mixed solid component having been cooled to burn and remove the combustible solid component.

  On the other hand, according to the present invention, the mixed gas component generated as a by-product by pyrolyzing the unnecessary tire can be subjected to a desulfurization process and sent to the fuel gas passage for reuse.

  As described above, in the method of the present invention, the components constituting the tire are pyrolyzed by heating at high temperature in an oxygen-free airtight state in a heat-resistant furnace in the shape of a tire without crushing unnecessary tires. Since the dry distillation means is used to separate the mixed gas component that vaporizes and the mixed solid component that remains in the furnace without vaporization, the preparation stage is simpler than the known method, and it is efficient and running Cost can also be greatly reduced.

  Further, in the present invention, it can be produced by sintering graphite from unnecessary tires in a heat-resistant furnace, and it is not necessary to use a cold trap or a filter as in the above-mentioned known method. Manufacturing time can be shortened, and fixed costs such as equipment costs can be greatly reduced.

  Hereinafter, the present invention will be described in more detail with reference to the most preferred embodiment of the present invention.

  FIG. 1 shows an example of an apparatus used when carrying out the method of the present invention (example method). Indicated by reference numeral 1 is a primary furnace made of refractory bricks, and indicated by reference numeral 2 A secondary furnace made of refractory bricks, indicated by reference numeral 3, is a sintered electric furnace.

The upper hatch 11 in the primary furnace 1 of FIG. 1 is opened, and then 30 280/85 R 24 radial tires T for passenger cars are put into the chamber 12 of the furnace to close the hatch 11 After sealing, the attached kerosene burner 13 is ignited and the inside of the furnace 12 is heated to about 1500 ° C. Due to this heating, the tire T in the chamber 12 partially burns at the limit of the amount of oxygen existing in the furnace, but then becomes oxygen-free, so that most of the input tire undergoes thermal decomposition and tire composition. It is dry-distilled into a mixed gas and a mixed solid component derived from min and separated. After about 30 minutes, since the dry distillation is completed, the combustion of the burner 13 is stopped. The mixed gas generated in this process passes through the gas flow path 14, rises in the chimney cylinder 22 disposed at the upper part of the secondary furnace 2, and comes into contact with the thioarsenate solution in a desulfurization apparatus (not shown), Hydrogen sulfide (H ₂ S) therein is separated and removed as hexathioarsenate (Tyrox = Thylox method). In the secondary furnace of FIG. 1, the desulfurized gas is discharged and discarded to the outside as it is, but the chimney cylinder 22 is connected to the fuel gas flow path and sent to the gas tank for storage or nearby. It can be supplied to ordinary households and reused as fuel gas.

  On the other hand, the mixed solid component generated by dry distillation separation from the unnecessary tire in the primary furnace 1 is transferred to the chamber 21 of the secondary furnace 2 while being heated to a high temperature. In addition to the carbon component, the transferred mixed solid component includes a metal component used as a reinforcing steel wire and zinc white. Therefore, the mixed solid component that is heated to a high temperature by introducing outside air (average 20 ° C.) into the chamber 21 of the secondary furnace 2 is liquid phase temperature below the ignition point of the rubber (in this embodiment, 200 ° C. The mixed solid component in the liquid phase is roughly settled and separated for each component by specific gravity. Thereafter, combustible solid components having a low ignition point are removed by flame radiation from the burner 23.

  Subsequently, the mixed solid component from which the combustible solid content is burned and removed is taken out, and the ash component and the metal component (the metal component derived from the wire as the reinforcing material) are separated and removed. Then, the remaining solid component is accommodated in the sintering mold 4 shown in FIG. 2, and the solid component accommodated in the mold 4 is accommodated in the chamber 31 of the sintering electric furnace 3 at a temperature of about 200 ° C. Sinter for 30 minutes by heating. Then, hydrogen, oxygen, nitrogen and the like contained in the solid component were removed, and graphite having a crystal structure as shown in the electron micrographs of FIGS. 3 and 4 was obtained.

  The graphite obtained in this way is a square plate body, which is formed into a size of 300 mm on a side and 30 mm in thickness, and is made of three JIS A 1108 “Method for testing compressive strength of concrete” and JIS When subjected to a strength test in accordance with A 5371 “Bending test method of flat plate for precast unreinforced concrete products”, the test results as shown in Table 1 and Table 2 below were obtained.

Further, regarding the far-infrared radiation performance of the graphite, when 600 g of “breaking ice” was placed on a transparent acrylic plate of the same size as the graphite plate in a room at a temperature of 12 ° C., the melting rate was compared. The ice placed on the graphite plate produced by the process was completely melted in 26 minutes, whereas the “split ice” placed on the transparent acrylic plate still had a 2/3 weight remaining unmelted ( Applicant's experiment). According to this experimental result, it can be said that the far-infrared radiation performance of the graphite produced by the method of the present invention is very large.

  As is clear from the above description, according to the present invention, it becomes possible to produce high-quality graphite with high quality and high yield at low cost with simple equipment from waste tires that have been difficult to dispose of conventionally. In industrial waste processing and in the development of recycled resources, the industrial utility value is very large.

FIG. 1 is a schematic diagram representing an apparatus used in carrying out the embodiment method of the present invention. FIG. 2 is a perspective view showing a mold for sintering used in carrying out the embodiment method of the present invention. FIG. 3 is an electron micrograph of magnification 1000 times showing the crystal structure of a graphite molded product produced by the method of the present invention. FIG. 4 is an electron micrograph at a magnification of 5000 showing the crystal structure of a graphite molded product produced by the method of the present invention.

Explanation of symbols

1 Primary furnace made of refractory bricks
11 Hatch
12 chambers
13 Burner
14 Gas flow path 2 Secondary furnace made of refractory brick
21 chamber
22 Chimney stack
23 Burner 3 Sintered electric furnace T Unnecessary tire

Claims (4)

  A furnace that does not vaporize with a mixed gas component that thermally decomposes and vaporizes components constituting the tire by heating at high temperature in an oxygen-free state in a tire-shaped heat-resistant furnace without crushing unnecessary tires After separating into the mixed solid component remaining in the interior, the mixed solid component remaining without being vaporized was radiated with a flame from the burner to burn and remove the combustible solid component, and then remained in the furnace without burning. A dry distillation type graphite manufacturing method using a waste tire as a raw material, wherein a lightweight ash component and a metal component are separated and removed from an incombustible component, and the remaining carbon component is sintered to obtain graphite.   The mixed gas component and the mixed solid component are separated by heating in an oxygen-free state at a temperature of about 1300 to 1500 ° C. in a primary heat-resistant primary furnace without crushing the unnecessary tire, The mixed solid component is transferred into a heat-resistant secondary furnace, a flame is emitted from a burner to burn and remove the combustible solid component, and the ash component and metal from the non-combustible solid component remaining in the secondary furnace. After removing the components, the remaining carbon component is filled in a mold, accommodated in an electric sintering furnace, sintered as graphite, and taken out. .   While the mixed gas component is desulfurized, the separated mixed solid component is brought to a liquid phase temperature below the ignition point of the tire rubber component by bringing outside air into contact therewith, and the mixed solid component is precipitated and separated by specific gravity. The method of producing dry distillation graphite using a waste tire as a raw material according to claim 1 or 2, wherein a flame is emitted from the burner to the mixed solid component having been cooled to burn and remove the combustible solid component.   The dry-distilled graphite production using a waste tire as a raw material according to any one of claims 1 to 3, wherein the desulfurized mixed gas component can be sent to the fuel gas flow path as a by-product and reused. Method.