Method and equipment for treating waste carbon fiber reinforced resin

Abstract

To provide a technique for performing heat treatment of a waste disposal of a carbon fiber reinforced resin at low cost, and effectively using a combustible gas generated in the heat treatment.SOLUTION: A processor 1 of a waste disposal of a carbon fiber reinforced resin comprises: a heat treatment device 2 for performing heat treatment to a waste disposal W of a carbon fiber reinforced resin; and a cement firing device 6 for using as heat sources, combustible gases C1-C3 generated from the waste disposal W in the heat treatment device 2 for firing a cement raw material. The heat treatment device 2 performs heat treatment of the waste disposal W by a tail gas G of the cement firing device 6 and / or a gas different from the tail gas G (overheated steam S) which is generated using the tail gas G as a heat source.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method and apparatus for treating waste carbon fiber reinforced plastics. [Background technology]

[0002] Carbon fiber reinforced resin is widely used in aircraft and automobile parts because it is lightweight yet has high mechanical strength. However, it is difficult to process the large amount of carbon fiber reinforced resin contained in used aircraft and automobiles. Furthermore, it is also problematic that a large amount of carbon fiber reinforced resin waste (unused scraps) is generated during the manufacturing process of aircraft and automobiles.

[0003] For example, Patent Document 1 below describes a method of thermally decomposing the resin contained in CFRP (a type of carbon fiber reinforced resin) waste by heat-treating the waste with superheated steam at 550° C. Furthermore, it describes the use of the carbon fibers (that were contained in the CFRP) remaining after the heat treatment as recycled carbon fibers.

[0004] However, the technology described in Patent Document 1 requires a lot of cost to obtain a heat source (e.g., fossil fuel) for heat-treating the carbon fiber reinforced resin waste, and the flammable gas generated by heat-treating the waste cannot be effectively utilized. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2017-82036 A Summary of the Invention [Problem to be solved by the invention]

[0006] Therefore, an object of the present invention is to heat-treat waste carbon fiber reinforced resin at low cost and to effectively utilize the combustible gas generated by this heat-treating. [Means for solving the problem]

[0007] The method for treating carbon fiber reinforced resin waste according to the first aspect of the present invention includes a heat treatment step of heat treating carbon fiber reinforced resin waste, and a gas utilization step of utilizing combustible gas generated from the waste in the heat treatment step as a heat source in a cement firing apparatus. In the heat treatment step, the waste is heat treated by exhaust gas from the cement firing apparatus and / or another gas generated by utilizing the exhaust gas as a heat source.

[0008] According to the first item, the heat (calories) contained in the exhaust gas from the cement calciner is used to heat-treat the carbon fiber reinforced resin waste, so that the waste can be heat-treated at low cost in the heat treatment process. Also, the combustible gas generated in the heat treatment process can be effectively used as a heat source in the cement calciner.

[0009] The method for treating waste carbon fiber reinforced resin according to a second aspect of the present invention further includes a superheated steam generation step, in which the exhaust gas is used as a heat source to generate superheated steam, which is the other gas.

[0010] According to the second item, superheated steam can be generated at low cost by utilizing the heat (calories) contained in the exhaust gas from the cement calciner. In addition, the resin contained in the carbon fiber reinforced resin waste can be efficiently pyrolyzed by this superheated steam, so that the carbon fibers contained in the waste can be efficiently recovered as recycled carbon fibers.

[0011] In the gas utilization step in the method for treating waste carbon fiber reinforced resin according to the third aspect of the present invention, the combustible gas is utilized as a heat source in the cement firing apparatus by injecting the combustible gas into the inside of a cement kiln in the cement firing apparatus.

[0012] According to this third item, the combustible gas generated by the heat treatment of carbon fiber reinforced resin waste is blown into the inside of a cement kiln (a high-temperature environment of about 1450°C). Therefore, even if this combustible gas contains dioxins, the dioxins contained in this combustible gas can be decomposed while this combustible gas is used to burn the cement raw materials inside the cement kiln.

[0013] The fourth aspect of the present invention provides a carbon fiber reinforced resin waste treatment device, which includes a heat treatment device for heat treating the carbon fiber reinforced resin waste, and a cement calcination device for calcining a cement raw material by utilizing, as a heat source, a combustible gas generated from the waste in the heat treatment device. The heat treatment device heats the waste by using exhaust gas from the cement calcination device and / or another gas generated by utilizing the exhaust gas as a heat source.

[0014] According to the fourth aspect, the heat (calories) contained in the exhaust gas from the cement calciner is used to heat-treat the carbon fiber reinforced resin waste, so that the waste can be heat-treated in the heat treatment device at low cost. Also, the combustible gas generated in the heat treatment device can be effectively used as a heat source in the cement calciner. Effect of the Invention

[0015] As described above, according to the present invention, waste carbon fiber reinforced resin can be heat-treated at low cost, and the flammable gas generated by this heat treatment can be effectively utilized. [Brief description of the drawings]

[0016] [Figure 1]1 is a schematic diagram showing a carbon fiber reinforced resin waste treatment device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Fig. 1 is a schematic diagram showing a carbon fiber reinforced resin waste treatment device according to one embodiment of the present invention. As shown in Fig. 1, this treatment device 1 includes a heat treatment device 2, a gas reforming device 3, a dust collection device 4, a carbon fiber recovery device 5, a cement calcination device 6, and a boiler 7. This treatment device 1 is installed within the site of a cement manufacturing plant.

[0018] The processing device 1 processes waste material W made of carbon fiber reinforced resin. Here, examples of carbon fiber reinforced resin include composite materials of thermosetting resin and carbon fiber (CFRP) and composite materials of thermoplastic resin and carbon fiber (CFRTP). Examples of thermosetting resins include epoxy resin, unsaturated polyester resin, and phenol resin. Examples of thermoplastic resins include nylon resin and polyester resin. Examples of carbon fibers include those used in the form of short fibers or continuous fibers or in the form of fabric (woven fabric, mat, etc.). Preferably, the waste material W is crushed in advance so that its maximum length is 5 cm or more and 30 cm or less.

[0019] The heat treatment device 2 performs a heat treatment process in which the waste material W made of carbon fiber reinforced resin is heat-treated under a non-oxidizing atmosphere at 300°C to 800°C. Specifically, the heat treatment device 2 heat-treats the waste material W using air A taken in from the outside and superheated steam S supplied from a boiler 7. The non-oxidizing atmosphere means a space in which the oxygen concentration is 10% or less (preferably 5% or less). For example, a fixed furnace, a rotary kiln, a stoker furnace, a vertical furnace, or a fluidized bed furnace can be used as the heat treatment device 2.

[0020] As a result, most of the resin contained in the waste W is thermally decomposed, and the fixed carbon attached to the carbon fiber contained in the waste W is burned. Then, combustible gas C1 is generated from the waste W due to the thermal decomposition of the resin and the combustion of the fixed carbon, and the carbon fiber F contained in the waste W remains inside the heat treatment device 2. It is not preferable to heat the waste W at a temperature below 300°C because the thermal decomposition rate of the resin contained in the waste W becomes slow. In addition, it is not preferable to heat the waste W to a temperature higher than 800°C because the carbon fiber contained in the waste W is oxidized and the quality as recycled carbon fiber is reduced.

[0021] The gas reformer 3 performs a gas reforming process to reform the combustible gas C1 discharged from the heat treatment device 2. Specifically, the combustible gas C1 is heated with an amount of oxygen less than the theoretical oxygen requirement in an environment of 1000°C or higher and 1200°C or lower (preferably 1100°C or lower). This causes partial combustion of the carbon content (organic content) contained in the combustible gas C1 to generate the combustible gas C2. The combustible gas C2 contains light components (carbon monoxide gas, methane gas, hydrogen gas, etc.) generated by decomposition of heavy hydrocarbons such as tar contained in the combustible gas C1.

[0022] Here, if the combustible gas C1 is heated to a temperature below 1000°C in the gas reforming device 3, the heavy hydrocarbons contained in the combustible gas C1 cannot be sufficiently decomposed. Also, if the combustible gas C1 is heated to a temperature above 1200°C in the gas reforming device 3, excessive heat is added to the combustible gas C1 compared to the amount of heat required to decompose the heavy hydrocarbons contained in the combustible gas C1, which is undesirable because it requires more costs than necessary.

[0023] The dust collector 4 performs a dust collection process for collecting the combustible gas C2 discharged from the gas reformer 3. The dust collector 4 collects carbon particles and the like contained in the combustible gas C2 discharged from the gas reformer 3 as dust D. For example, a bag filter or a cyclone can be used as the dust collector 4.

[0024] The carbon fiber recovery device 5 performs a carbon fiber recovery step of recovering the carbon fibers F discharged from the inside of the heat treatment device 2.

[0025] The cement calcination apparatus 6 performs a gas utilization step in which the combustible gas C3 discharged from the dust collector 4 is utilized as a heat source for calcining the cement raw material (not shown). Specifically, the combustible gas C3 is utilized as a heat source in the cement kiln (cement calcination apparatus 6) by blowing the combustible gas C3 into the cement kiln from a burner (not shown) of the cement kiln (not shown).

[0026] The boiler 7 performs a superheated steam generating process in which superheated steam S is generated by utilizing the exhaust gas G from the cement burning apparatus 6 as a heat source.

[0027] Next, the operation of the processing device 1 shown in Fig. 1 (corresponding to a method for processing waste carbon fiber reinforced resin according to one embodiment of the present invention) will be described. The operation of this processing device 1 is performed simultaneously and continuously in each of the components 2 to 7, but for the sake of convenience, the operation of each of the components 2 to 7 will be described in order here.

[0028] First, cement raw materials (not shown) are burned in a cement burning apparatus 6. Next, exhaust gas G from the cement burning apparatus 6 is introduced into a boiler 7 to generate superheated steam S. Thereafter, the superheated steam S, air A, and waste material W of carbon fiber reinforced resin are supplied to a heat treatment apparatus 2 to heat-treat the waste material W.

[0029] As a result, in a non-oxidizing atmosphere of 300°C to 800°C, which is the internal environment of the heat treatment device 2, the resin contained in the waste material W is thermally decomposed and the fixed carbon attached to the carbon fibers contained in the waste material W is burned. Then, inside the heat treatment device 2, combustible gas C1 is generated from the waste material W due to the thermal decomposition of the resin and the combustion of the fixed carbon, and the carbon fibers F contained in the waste material W slide down the inclined bottom surface of the heat treatment device 2 and are discharged to the outside of the heat treatment device 2.

[0030] Here, the combustible gas C1 is drawn from inside the heat treatment device 2 to the gas reformer 3 by an induction fan (not shown). Meanwhile, the carbon fibers F discharged from inside the heat treatment device 2 are recovered in a carbon fiber recovery device 5. The recovered carbon fibers F can be used as recycled carbon fibers or fuel for a cement burning device 6.

[0031] The gas reformer 3 reforms the combustible gas C1 to generate a combustible gas C2. The combustible gas C2 is collected in the dust collector 4, whereby the combustible gas C2 is separated into a combustible gas C3 and dust D. Furthermore, the combustible gas C3 is blown into the cement kiln of the cement firing device 6, whereby the combustible gas C3 is used as a heat source (combustion gas) in the cement kiln (cement firing device 6). Furthermore, the collected dust D is used as solid fuel in the cement firing device 6.

[0032] As described above, according to the above embodiment, the waste material W made of carbon fiber reinforced resin is heat-treated by utilizing the heat (calories) contained in the exhaust gas G from the cement burning apparatus 6, so that the waste material W can be heat-treated at low cost in the heat treatment apparatus 2. In addition, the combustible gases C1 to C3 generated in the heat treatment apparatus 2 can be effectively used as a heat source in the cement burning apparatus 6.

[0033] Moreover, according to the above embodiment, it is possible to generate superheated steam S at low cost by utilizing the heat (calories) contained in the exhaust gas G from the cement burning apparatus 6. Moreover, by heat treating the carbon fiber reinforced resin waste W with this superheated steam S, it is possible to efficiently pyrolyze the resin contained in the waste W, and therefore it is possible to efficiently recover the carbon fibers F contained in the waste W as recycled carbon fibers.

[0034] Furthermore, according to the above embodiment, the combustible gases C1 to C3 generated by heat treating the carbon fiber reinforced resin waste W are blown into the inside of the cement kiln (high temperature environment of about 1450°C). Therefore, even if the combustible gases C1 to C3 contain dioxins, the combustible gases C1 to C3 can be used to burn the cement raw materials inside the cement kiln, while the dioxins contained in the combustible gases C1 to C3 can be decomposed inside the cement kiln.

[0035] In the above embodiment, the combustible gas C3 is used as the heat source in the cement burning apparatus 6. However, the combustible gases C1 and C2 may be used as the heat source in the cement burning apparatus 6.

[0036] Furthermore, in the above embodiment, the waste W inside the heat treatment device 2 is heat-treated by the superheated steam S, but the waste W inside the heat treatment device 2 may be heat-treated by the exhaust gas G from the cement burning device 6. Also, nitrogen gas, argon gas, etc. may be heated by the exhaust gas G from the cement burning device 6, and the waste W inside the heat treatment device 2 may be heat-treated by the heated nitrogen gas, argon gas, etc.

[0037] In addition, in the above embodiment, the combustible gas C3 is injected into the cement kiln of the cement burning apparatus 6, but it may also be injected into a calciner (not shown) or a preheater (not shown) in the cement burning apparatus 6. In addition, the recycled carbon fibers recovered by the carbon fiber recovery apparatus 5 may be classified according to the intended use by performing screening, specific gravity sorting, optical sorting, or the like.

[0038] Thus, according to the above embodiment, the waste material W can be heat-treated by the superheated steam S without using fossil fuels in the heat treatment device 2, and the cement raw materials can be burned by the combustible gas C3 without using fossil fuels in the cement burning device 6, so that the amount of carbon dioxide discharged into the atmosphere from these devices 2 and 6 can be kept low. Furthermore, even if the combustible gases C1 to C3 discharged from the heat treatment device 2 contain dioxins, these combustible gases C1 to C3 can be used to burn the cement raw materials inside the cement kiln (cement burning device 6), and the dioxins contained in these combustible gases C1 to C3 can be decomposed inside the cement kiln without being discharged into the atmosphere.

[0039] According to the above embodiment, the carbon fiber reinforced plastic waste W can be recovered in the carbon fiber recovery device 5 and used as recycled carbon fiber (expensive and versatile material), and the combustible gas C1 discharged from the heat treatment device 2 can be used as a heat source in the cement burning device 6. In particular, since the carbon fiber reinforced resin waste W can be treated with various resins such as epoxy resin, unsaturated polyester resin, phenol resin, nylon resin, and polyester resin as described above, various types of carbon fiber reinforced resin waste W can be recycled. Furthermore, even if the carbon fiber reinforced resin waste W contains other resin members different from the carbon fiber reinforced resin, it can be treated in the same way as the resin contained in the carbon fiber reinforced resin. This makes it possible to realize zero emissions in the treatment of the carbon fiber reinforced resin waste W. [Explanation of symbols]

[0040] 1. Carbon fiber reinforced plastic waste treatment equipment 2. Heat treatment equipment 3 Gas Reformer 4 Dust collector 5 Carbon fiber recovery equipment 6. Cement baking equipment 7. Boiler A. Air C1~C3 Combustible gases D. Dust F Carbon fiber G. Exhaust gas S Superheated steam W Carbon fiber reinforced plastic waste

Claims

1. a heat treatment process in which carbon fiber reinforced resin waste is heat treated in a non-oxidizing atmosphere having an oxygen concentration of 10% or less and a temperature of 800° C. or less, thereby thermally decomposing the resin contained in the waste to generate a combustible gas, and further combusting fixed carbon attached to the carbon fibers contained in the waste; a gas utilization step of utilizing the combustible gas generated from the waste in the heat treatment step as a heat source in a cement burning apparatus; A carbon fiber recovery process for recovering the carbon fibers obtained by the heat treatment in the heat treatment process, A method for treating carbon fiber reinforced resin waste, characterized in that in the heat treatment step, the waste is heat-treated using exhaust gas from the cement burning apparatus and / or another gas generated by utilizing the exhaust gas as a heat source.

2. Further comprising a superheated steam generating step, 2. The method for treating waste carbon fiber reinforced resin according to claim 1, wherein in the superheated steam generating step, the exhaust gas is utilized as a heat source to generate the separate gas, that is, the superheated steam.

3. 3. The method for treating waste carbon fiber reinforced resin according to claim 1, wherein in the gas utilization step, the combustible gas is utilized as a heat source in the cement burning apparatus by injecting the combustible gas into the inside of a cement kiln in the cement burning apparatus.

4. a heat treatment device for heat-treating carbon fiber reinforced resin waste in a non-oxidizing atmosphere having an oxygen concentration of 10% or less and 800° C. or less, thereby thermally decomposing the resin contained in the waste to generate a combustible gas, and further combusting fixed carbon attached to the carbon fibers contained in the waste; a cement calcination device that uses the combustible gas generated from the waste in the heat treatment device as a heat source to calcinate a cement raw material; a carbon fiber recovery device that recovers the carbon fibers obtained by the heat treatment in the heat treatment step, The heat treatment device heats the waste using exhaust gas from the cement burning device and / or another gas generated by utilizing the exhaust gas as a heat source.

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