JP2001316517A - Processing method and equipment for waste plastics - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a processing method for waste plastics capable of enhancing efficiency of a catalyst reaction in a decomposition treatment of the waste plastics using a catalyst. SOLUTION: This processing method for waste plastics reclaims a catalytic reaction product by vaporizing waste plastics in a pyrolizing tank 2 by a pyrolysis reaction and then contacting the pyrolysis product gas with a silicate catalyst containing gallium in a catalytic reactor 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention treats waste plastics such as polyethylene and polypropylene contained in waste such as municipal waste and recovers chemical raw materials such as BTX (benzene, toluene and xylene) and hydrogen. Method and apparatus.

[0002]

2. Description of the Related Art Conventionally, as an attempt to reuse waste plastic such as polyolefin plastic such as polyethylene and polypropylene contained in waste such as municipal waste, an attempt has been made to use waste plastic such as an activated carbon catalyst carrying iron or platinum. There is a method of thermally decomposing by heat treatment in the presence of a catalyst to obtain a processed product useful as a fuel or a chemical raw material. FIG. 6 shows a processing apparatus capable of implementing one example of a conventional waste plastic processing method. The processing apparatus includes a reaction tank 51 for melting waste plastic and contacting it with a catalyst 51a, and a high boiling point in a catalyst reaction product. A capacitor 52 for separating components is provided. The catalyst 51 a is contained in the reaction tank 51. In order to perform processing of waste plastic using this processing apparatus, waste plastic P is heated in a reaction tank 51 using a heater 51b in the presence of the catalyst 51a,
The catalyst reaction product is led to the condenser 52 through the path 53 and recovered as a decomposition product.

[0003]

However, according to the above-mentioned prior art, the waste plastic melted by the heat treatment adheres to the surface of the catalyst 51a, and the adhered plastic is formed between the waste plastic P and the catalyst 51a. This has hindered efficient contact of the catalyst and reduced the efficiency of the catalytic reaction. The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a waste plastic treatment method capable of increasing the catalytic reaction efficiency in decomposing waste plastic using a catalyst.

[0004]

SUMMARY OF THE INVENTION According to the present invention, there is provided a method for treating waste plastic, comprising: vaporizing waste plastic by pyrolysis;
The obtained pyrolysis gas is brought into contact with a gallium-containing silicate catalyst, and a catalytic reaction product is recovered. In this treatment method, the waste plastic is made into a pyrolysis gas having better fluidity than liquid, so that the pyrolysis gas can be efficiently contacted with the catalyst. Therefore, the efficiency of the catalytic reaction (decomposition of thermal decomposition gas, cyclization reaction) can be enhanced, and a processed product containing aromatic hydrocarbons such as BTX at a high concentration useful as a chemical raw material can be recovered. In addition, a processed material containing high-concentration hydrogen can be recovered. As the gallium-containing silicate, it is preferable to use an H-type gallium silicate. Further, the waste plastic processing apparatus of the present invention includes a pyrolysis tank for thermally decomposing and vaporizing waste plastic, and a catalytic reaction tank for bringing the pyrolysis gas vaporized in the pyrolysis tank into contact with the gallium-containing silicate catalyst. It is characterized by the following. In this apparatus, since the pyrolysis gas is introduced into the catalyst decomposition tank, the pyrolysis gas can be easily and efficiently brought into contact with the gallium-containing silicate catalyst. Therefore, BTX useful as a chemical raw material is enhanced by increasing the catalytic reaction efficiency.
A treated product containing aromatic hydrocarbons at a high concentration can be easily recovered. Further, a processed material containing high-concentration hydrogen can be easily recovered. By providing the catalyst reaction tank in the pyrolysis tank, the inside of the catalyst reaction tank can be heated by residual heat when the waste plastic is thermally decomposed in the pyrolysis tank. For this reason, it is not necessary to heat the catalyst reaction tank independently, so that equipment costs and heating costs can be kept low. Further, the catalyst reaction tank may be provided outside the thermal decomposition tank and may be configured such that the internal temperature can be arbitrarily set. In this case, the temperature condition during the catalyst reaction in the catalyst reaction tank is used. Can be set arbitrarily. For this reason, it becomes easy to optimize the temperature conditions during the catalytic reaction, and the catalytic reaction efficiency can be increased. Further, the catalyst reaction tank may be configured such that the gallium-containing silicate catalyst flows by the pyrolysis gas. In this case, the catalyst can be brought into contact with the pyrolysis gas while flowing the catalyst, and Nearly all surfaces can be contacted with the pyrolysis gas. Therefore, the contact efficiency between the pyrolysis gas and the catalyst can be increased, and the catalytic reaction efficiency can be improved.

[0005]

FIG. 1 shows a first embodiment of a waste plastic processing apparatus according to the present invention. The processing apparatus shown in FIG. 1 is a thermal plasticizer for thermally decomposing waste plastic supplied from a raw material supply section 1. A cracking tank 2, a catalytic reaction tank 3 for bringing the pyrolysis gas thermally decomposed and vaporized in the pyrolysis tank 2 into contact with the gallium-containing silicate catalyst 8 a, and a catalyst reaction product obtained in the catalyst reaction tank 3. A reflux condenser 4 for separating a molecular component, a first condenser 5 for condensing and separating a high boiling point component in a reaction product from which a polymer component has been separated in the reflux condenser 4,
And a second condenser 6 for further condensing and separating low-boiling components in the reaction product passed through the condenser 5.

[0006] The pyrolysis tank 2 is provided with a heater 2a.
The waste plastic in the tank can be heated and thermally decomposed by the heater 2a. The thermal decomposition tank 2 is provided with a stirrer 2b so that the waste plastic in the tank can be heated while stirring.
An inert gas introduction pipe 14 is connected to the pyrolysis tank 2 so that an inert gas such as nitrogen or helium can be introduced into the pyrolysis tank 2.

The catalyst reactor 3 has a catalyst layer 8 in an outer cylinder 7 filled with a gallium-containing silicate catalyst 8a. As the gallium-containing silicate, gallium silicate can be used, and in particular, xM ^I ₂
O.yGa ₂ O ₃ .zSiO ₂ .nH ₂ O (M: Na, K
And the like) are preferably used. As the catalyst 8a, it is preferable to use a gallium-containing silicate formed into a particle having an average particle size of, for example, 0.2 to 5 mm. Further, a material in which gallium is supported on a carrier such as zeolite or activated carbon (for example, Ga-HZSM-5) can be used.

The catalytic reaction tank 3 is disposed inside the pyrolysis tank 2, and the pyrolysis gas which has been pyrolyzed and vaporized is brought into contact with the gallium-containing silicate catalyst 8 a of the catalyst layer 8 in the pyrolysis tank 2. You can do it.

The high-boiling point component is condensed as a polymer component from the catalyst reaction product in the reflux unit 4, the condensed polymer component is separated from other components, and returned to the pyrolysis tank 2 through the path 10. A configuration can be employed.

The first condenser 5 cools the catalyst reaction product having passed through the reflux condenser 4 with cooling water flowing through the cooling water flow path 12 so that high boiling components in the reaction product can be condensed. Has become. The second condenser 6 cools the catalyst reaction product that has passed through the first condenser 5 with cooling water flowing through the cooling water flow path 13 so that low boiling components in the reaction product can be condensed. I have.

Hereinafter, an embodiment of the method for treating waste plastic of the present invention will be described with reference to an example in which the above-described processing apparatus is used. Examples of the waste to be treated by the waste plastic treatment method of the present invention include waste plastics derived from municipal solid waste and industrial waste, such as those containing polyolefin plastics such as polyethylene and polypropylene.

In the processing method of this embodiment, first, waste plastic, preferably ground to an appropriate particle size, is charged into the pyrolysis tank 2 through the raw material supply unit 1, and the waste plastic is preferably heated using the heater 2a. Is 375-550 ° C
(More preferably 425 to 500 ° C.) to cause thermal decomposition. If this temperature is lower than the above range, the thermal decomposition of the waste plastic becomes insufficient, and if it exceeds the above range, the thermal decomposition (low molecular weight reduction) of the waste plastic becomes excessive, and aromatic carbon in the reaction product described later becomes excessive. It is not preferable because the hydrogen content decreases.

By this heat treatment, the waste plastic is
For example, hydrocarbons having about 4 to 10 carbon atoms are decomposed and vaporized to become pyrolysis gases. When the waste plastic is introduced into the pyrolysis tank 2, an inert gas such as nitrogen gas is introduced into the pyrolysis tank 2 through the introduction pipe 14 in advance, and the waste plastic is introduced under an inert gas atmosphere. Heating is preferred.

The pyrolysis gas generated in the pyrolysis tank 2 is introduced into the catalyst reaction tank 3 and flows through the catalyst reaction tank 3,
It comes into contact with the gallium-containing silicate catalyst 8a constituting the catalyst layer 8. The temperature condition when bringing the pyrolysis gas into contact with the catalyst 8a is 375 to 550 ° C. (preferably 500 to 550 ° C.).
° C). If this temperature is less than the above range, the catalytic reaction becomes difficult to proceed, the aromatic hydrocarbon content in the reaction product decreases, and if it exceeds the above range, the decomposition of the pyrolysis gas becomes excessive and the reaction product contains It is not preferable because the aromatic hydrocarbon content is reduced.

The rate at which the pyrolysis gas is supplied to the catalyst reaction tank 3 is 3 to 15 g of the pyrolysis gas / g catalyst · hr (Time
Factor (= W / F, W: amount of catalyst, F: supply rate of pyrolysis gas) = 4 to 20 g catalyst · min / g pyrolysis gas)
It is preferable to set so that

In the catalytic reactor 3, a part of the pyrolysis gas is further decomposed by the action of the gallium-containing silicate catalyst 8a. A part of the decomposition product and the pyrolysis gas is
A is cyclized by the action of a to become an aromatic hydrocarbon. Thus, in the catalyst reaction tank 3, the pyrolysis gas is decomposed and cyclized by the action of the catalyst 8a, and as a result, hydrogen (H ₂ ), a hydrocarbon having 1 to 4 carbon atoms (hereinafter referred to as C1 to C4 hydrocarbon). ), Aromatic hydrocarbons (benzene, toluene, xylene, etc.). Hereinafter, benzene, toluene, and xylene are abbreviated as BTX.

Next, the catalyst reaction product that has passed through the catalyst reaction tank 3 is introduced into the reflux unit 4 through the path 9, where the catalyst reaction product is cooled to condense a part of the catalyst reaction product and condense it. The material is separated from the other parts and returned to the pyrolysis tank 2 through the path 10. The condensate contains a large amount of a polymer component that is an undecomposed component remaining in the catalyst reaction product. This polymer component is again subjected to heat treatment in the thermal decomposition tank 2 to be thermally decomposed.

Next, the catalytic reaction product from which the polymer component has been separated in the reflux unit 4 is introduced into the first condenser 5 through a path 11, where it is cooled by cooling water flowing through a cooling water flow path 12, High boiling components in the product are condensed. If the cooling temperature at the time of cooling the catalytic reaction product is too high, aromatic hydrocarbons such as BTX in the high-boiling components are difficult to condense, and the content of the aromatic hydrocarbons in the condensate becomes low. If the amount is too high, low molecular hydrocarbons and the like are easily condensed, so that the content of the aromatic hydrocarbons in the condensate becomes low. Therefore, this cooling temperature
The temperature is preferably 30 to 50 ° C.

The condensed high-boiling components are introduced into an oil / water separator 16 via a path 15, where they are recovered through a recovery path 17 after water is separated. The recovered high-boiling components contain a high concentration of aromatic hydrocarbons such as BTX.

Next, the reaction product that has passed through the first condenser 5 is introduced into the second condenser 6 through a passage 18, where it is cooled by cooling water flowing through a cooling water passage 13. In the second condenser 6, low-boiling components including aromatic hydrocarbons such as BTX, which have passed through the first condenser 5 without being condensed, are condensed, introduced into the recovery unit 20 through the path 19, and then recovered through the recovery path 21. Is done.

Next, the low-boiling components that have passed through the second condenser 6 are introduced into the drain 32 through the path 22, where water and the like are separated, and then recovered through the recovery path 24.
Low-boiling component collected is that containing a high concentration of hydrogen (H ₂₎ and C1~C4 hydrocarbons.

The components recovered through the recovery paths 17 and 21 contain a high concentration of aromatic hydrocarbons such as BTX and can be used as chemical raw materials. The low-boiling components recovered through the recovery path 24 contain high-concentration hydrogen (H ₂ ) and can be used as a hydrogen-containing gas for a fuel cell system. Further, it can be used for reforming petroleum hydrocarbons and petroleum desulfurization. The low boiling point component is C
Since it contains 1 to C4 hydrocarbons, it can be used as a fuel gas.

In the above waste plastic treatment method,
The waste plastic is vaporized by pyrolysis in the pyrolysis tank 2, and the obtained pyrolysis gas is led to the catalyst reaction tank 3 and circulated in the catalyst reaction tank 3 to the gallium-containing silicate catalyst 8 a constituting the catalyst layer 8. Make contact. At this time, since the pyrolysis gas is a gas having better fluidity than the liquid, the pyrolysis gas flows without staying in the catalyst reaction tank 3. Therefore, the pyrolysis gas can be efficiently brought into contact with the gallium-containing silicate catalyst 8a. Therefore, the efficiency of the catalytic reaction (decomposition of thermal decomposition gas, cyclization reaction) can be enhanced, and a processed product containing aromatic hydrocarbons such as BTX at a high concentration useful as a chemical raw material can be recovered. In contrast, in the conventional method of contacting the waste plastic with the catalyst in a molten state, the molten plastic adheres to the catalyst surface, and the adhered plastic prevents efficient contact between the waste plastic and the catalyst. The efficiency of the catalytic reaction may be reduced.

The use of a gallium-containing silicate catalyst to recover aromatic hydrocarbons such as BTX in high yield is attributable to the ability of the gallium-containing silicate catalyst to degrade plastic and cyclize decomposition products. It is believed that the ratio is suitable for converting the waste plastic into an aromatic hydrocarbon. Further, the reason why the low-boiling component recovered through the recovery path 24 contains high-concentration hydrogen is that when the chain hydrocarbon in the reaction product forms a benzene ring during the generation of the aromatic hydrocarbon, This is probably because surplus hydrogen is easily generated as a simple substance.

Further, in the waste plastic processing apparatus, the pyrolysis tank 2 for pyrolyzing the waste plastic and the pyrolysis gas pyrolyzed and vaporized in the pyrolysis tank 2 are brought into contact with the gallium-containing silicate catalyst 8a. A catalytic reaction tank 3 for causing the reaction and a reflux unit 4 for condensing and separating the polymer component in the catalytic reaction product
Therefore, the pyrolysis gas obtained by pyrolyzing the waste plastic in the pyrolysis tank 2 can be easily and efficiently brought into contact with the gallium-containing silicate catalyst 8a in the catalytic reaction tank 3. Therefore, the efficiency of the catalytic reaction (decomposition of thermal decomposition gas, cyclization reaction) can be enhanced, and a treated product containing aromatic hydrocarbons such as BTX at a high concentration can be easily recovered. Further, a processed material containing high-concentration hydrogen can be easily recovered.

Further, since the catalytic reaction tank 3 is disposed in the thermal decomposition tank 2, the inside of the catalytic reaction tank 3 can be heated by residual heat when the waste plastic is thermally decomposed in the thermal decomposition tank 2. For this reason, it is not necessary to heat the catalyst reaction tank 3 independently, and a heater dedicated to the catalyst reaction tank 3 is not required, and equipment costs and heating costs can be reduced.

FIG. 2 shows a waste plastic processing apparatus according to a second embodiment of the present invention.
A pyrolysis tank 2 for thermally decomposing waste plastic supplied from the raw material supply unit 1, a catalytic reaction tank 23 for bringing pyrolysis gas thermally decomposed and vaporized in the pyrolysis tank 2 into contact with the gallium-containing silicate catalyst 28a, A condenser 4 for separating the polymer component in the catalyst reaction product obtained in the catalyst reaction tank 23, and a condenser for condensing and separating the high boiling point component in the reaction product from which the polymer component has been separated in the condenser 4 25. The catalyst reaction tank 23 includes a catalyst layer 28 in which an outer cylinder 27 is filled with a catalyst 28a. The catalyst layer 28 is provided outside the pyrolysis tank 2 and the internal temperature can be arbitrarily set by a heater 23a. I have. Further, in the catalyst reaction tank 23, a fixed bed system in which the gallium-containing silicate catalyst 28a filled in the outer cylinder 27 is not displaced with respect to the outer cylinder 27 when flowing the pyrolysis gas can be adopted.

In order to treat the waste plastic using the above-mentioned apparatus, the waste plastic is vaporized by pyrolysis in the pyrolysis tank 2 and the obtained pyrolysis gas is led to the catalyst reaction tank 23 through the passage 26. The gallium-containing silicate catalyst 28a is brought into contact with the catalyst 28a, and the obtained catalyst reaction product is led to the condenser 25 via the reflux condenser 4, where the high-boiling components are condensed and recovered through the recovery path 29, and the low-boiling components are recovered through the recovery path 30. Collect through.

In the above processing apparatus, similarly to the processing apparatus of the first embodiment shown in FIG. 1, the catalytic reaction efficiency is increased, and a high boiling point component containing a high concentration of aromatic hydrocarbons such as BTX useful as a chemical raw material is contained. It can be easily collected. further,
In the processing apparatus of the present embodiment, the catalyst reaction tank 23 is provided outside the pyrolysis tank 2 and the internal temperature can be set arbitrarily. It can be set arbitrarily. For this reason, the catalytic reaction efficiency can be increased by optimizing the temperature conditions during the catalytic reaction.

FIG. 3 shows a waste plastic processing apparatus according to a third embodiment of the present invention. In the processing apparatus shown in FIG. 3, a particulate gallium-containing silicate catalyst is supplied to a catalyst reaction tank 33 by flowing a pyrolysis gas. A fluidized bed system in which 38a flows in the outer cylinder 37 is adopted. At the subsequent stage of the catalyst reaction tank 33, there is provided a separation unit 34 for separating and collecting the catalyst that has flowed out of the tank together with the catalyst reaction product that has passed through the catalyst reaction tank 33, and returns the collected catalyst to the catalyst reaction tank 33 through a path 35. You can do it.

In order to treat waste plastics using the above treatment apparatus, waste plastics are vaporized by pyrolysis in the pyrolysis tank 2 and the obtained pyrolysis gas is led to the catalyst reaction tank 33 through the path 31. To contact the gallium-containing silicate catalyst 38a. At this time, the gallium-containing silicate catalyst 38a flows in the outer cylinder 37 due to the pyrolysis gas introduced into the catalyst reaction tank 33 and flowing in the outer cylinder 37, and comes into contact with the pyrolysis gas while flowing. Next, the catalyst reaction tank 3
The catalyst reaction product passed through 3 is led to the condenser 25 through the reflux unit 4, where the high-boiling components are condensed and collected in the recovery path 29.
And the low-boiling components are recovered through the recovery path 30. At this time, the catalyst reaction vessel 3
The catalyst that has flowed out of the tank 3 is recovered by the separation unit 34 and returned to the catalyst reaction tank 33 through the path 35.

In the above processing apparatus, similarly to the processing apparatus of the first embodiment shown in FIG. 1, the catalytic reaction efficiency is increased, and a high boiling point component containing a high concentration of aromatic hydrocarbons such as BTX useful as a chemical raw material is contained. It can be easily collected. further,
In the processing apparatus of the present embodiment, since the fluidized bed system is adopted for the catalyst reaction tank 33, the granular catalyst 38a is
It can be brought into contact with the pyrolysis gas while flowing inside. Therefore, almost the entire surface of the catalyst 38a can be brought into contact with the pyrolysis gas. Therefore, the contact efficiency between the pyrolysis gas and the catalyst can be increased, and the catalytic reaction efficiency can be improved.

FIG. 4 shows a waste plastic processing apparatus according to a fourth embodiment of the present invention.
It is obtained in a melting tank 42 for melting waste plastic introduced from the raw material supply unit 41, a catalyst reaction tank 43 for thermally decomposing and vaporizing a molten material melted in the melting tank 42 and contacting with a catalyst, and a catalyst reaction tank 43. And a condenser 44 for condensing and separating high-boiling components in the catalyst reaction product. The catalyst reaction tank 43 has a catalyst layer 45 filled with a gallium-containing silicate catalyst. For the catalyst reaction tank 43, a fixed bed method in which the catalyst is not displaced when the pyrolysis gas flows can be adopted. The condenser 44 has a storage tank 44 for storing a refrigerant 44b for cooling the inside of a conduit 46 for leading a catalyst reaction product.
a.

In order to treat the waste plastic using the above-mentioned treatment apparatus, the waste plastic is melted in a melting tank 42, and the obtained melt is guided to a catalyst reaction tank 43, where it is thermally decomposed and vaporized, and gallium is added. The resulting catalyst reaction product is brought into contact with the silicate catalyst, and the resulting catalyst reaction product is led to a condenser 44 through a pipe 46, where the high-boiling components are condensed and recovered. The low-boiling components are recovered through a recovery path 47. At this time, it is preferable that an inert gas is introduced into the melting tank 42 and the catalyst reaction tank 43 through the paths 48 and 49, and the above-described thermal decomposition and catalytic reaction are performed in an inert gas atmosphere.

In the above-described processing apparatus, similarly to the processing apparatus of the first embodiment shown in FIG. 1, the catalytic reaction efficiency is increased and aromatic hydrocarbons such as BTX useful as chemical raw materials such as plastic raw materials are contained at a high concentration. High boiling components can be easily recovered. Further, in the processing apparatus according to the present embodiment, the apparatus configuration is simple, so that equipment costs can be reduced.

[0036]

EXAMPLES The effects of the present invention will be clarified by showing specific examples. (Example) The following processing test was performed using the processing apparatus shown in FIG. As the gallium-containing silicate catalyst, H-type gallium silicate (Si / Ga = 25) has an average particle diameter of 0.8 m.
m was used. The polyethylene is heated and melted at 270 ° C. under a nitrogen gas atmosphere in the melting tank 42, and the obtained melt is 425 to 425 in the catalyst reaction tank 43.
It was thermally decomposed and vaporized at 525 ° C., and was brought into contact with the catalyst. At this time, the rate at which the melt is supplied to the catalyst reaction tank 43 is 3 to 30 g plastic / g catalyst · hr.
(Time Factor (= W / F, W: catalyst amount,
F: plastic feed rate) 2 to 20 g catalyst · min /
g plastic). Catalyst reaction tank 4
The catalyst reaction product passed through No. 3 was led to a condenser 44, high boiling components were recovered, and the content of BTX was measured.

(Comparative Example) The following processing tests were performed using the processing apparatus shown in FIG. 2 g of polyethylene and 1.
The mixture with 2 g of the catalyst is heated and melted in a reaction vessel 51 at 425 to 500 ° C. in the presence of the catalyst, and the catalyst reaction product is led to a condenser 52 through a path 53,
The high boiling components were collected and subjected to component analysis. Reaction tank 5
The inside of 1 was made a nitrogen atmosphere by a nitrogen gas introduced through a passage 54.

FIG. 5 shows the results of component analysis of the products recovered in the above Examples and Comparative Examples. From FIG. 5, in the comparative example in which the plastic was brought into contact with the catalyst in a molten state, the BTX content in the recovered material was low, whereas in the example in which the plastic was thermally decomposed and vaporized to contact the catalyst as a pyrolysis gas, It can be seen that a high BTX yield was obtained.

[0039]

According to the waste plastic treatment method of the present invention,
Since the waste plastic is vaporized by pyrolysis and the obtained pyrolysis gas is brought into contact with the gallium-containing silicate catalyst, the pyrolysis gas can be efficiently brought into contact with the gallium-containing silicate catalyst. Therefore, it is possible to enhance the efficiency of the catalytic reaction and to recover a treated product containing a high concentration of aromatic hydrocarbons such as BTX useful as a chemical raw material. In addition, a processed material containing high-concentration hydrogen can be recovered.

Further, the waste plastic processing apparatus of the present invention
Equipped with a pyrolysis tank for pyrolyzing and vaporizing waste plastics and a catalytic reaction tank for bringing the pyrolysis gas vaporized in the pyrolysis tank into contact with the gallium-containing silicate catalyst. Good contact with gallium-containing silicate catalysts. Therefore, it is possible to enhance the catalytic reaction efficiency and easily recover a treated product containing a high concentration of an aromatic hydrocarbon such as BTX which is useful as a chemical raw material. Further, a processed material containing high-concentration hydrogen can be easily recovered. Further, by providing the catalyst reaction tank in the thermal decomposition tank, the inside of the catalytic reaction tank can be heated by residual heat when the waste plastic is thermally decomposed in the thermal decomposition tank. For this reason, it is not necessary to heat the catalyst reaction tank independently, so that equipment costs and heating costs can be kept low. In addition, by configuring the catalyst reaction tank outside the pyrolysis tank and arbitrarily setting the internal temperature, it is possible to arbitrarily set the temperature conditions during the catalyst reaction in the catalyst reaction tank. it can. Therefore, by optimizing the temperature conditions during the catalytic reaction, the catalytic reaction efficiency can be increased. Also, by configuring the catalyst reaction tank so that the gallium-containing silicate catalyst flows by the pyrolysis gas, the catalyst can be brought into contact with the pyrolysis gas while flowing, and almost the entire surface of the catalyst is pyrolyzed. Can be contacted with gas. Therefore, the contact efficiency between the pyrolysis gas and the catalyst can be increased, and the catalytic reaction efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a processing apparatus used for carrying out an embodiment of a waste plastic processing method of the present invention.

FIG. 2 is a schematic configuration diagram showing a processing apparatus suitably used for carrying out another embodiment of the waste plastic processing method of the present invention.

FIG. 3 is a schematic configuration diagram showing a processing apparatus suitably used for carrying out another embodiment of the waste plastic processing method of the present invention.

FIG. 4 is a schematic configuration diagram showing a processing apparatus suitably used for carrying out another embodiment of the waste plastic processing method of the present invention.

FIG. 5 is a graph showing test results.

FIG. 6 is a schematic configuration diagram showing a processing apparatus suitably used for carrying out an example of a conventional waste plastic processing method.

[Explanation of symbols]

2 ... thermal decomposition tank, 3, 23, 33, 43 ... catalyst reaction tank,
8a, 28a, 38a ... gallium-containing silicate catalyst

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C07C 15/06 C07C 15/06 15/08 15/08 C10G 1/10 C10G 1/10 (72) Inventor Masahiro Ito 1 Shin-Nakahara-cho, Isogo-ku, Yokohama-shi, Kanagawa Ishikawashima-Harima Heavy Industries Co., Ltd. 4F301 AA12 CA09 CA25 CA27 CA51 CA53 CA61 CA72 CA74 4G069 AA02 AA15 BA15A BA15B BC17A BC17B CB35 CB38 DA06 EA02Y EB18Y EC22X FB66 4H006 AA05 AC26 CA09 CA33 CA01 CA14

Claims (6)

[Claims] 1. A method for treating waste plastic, comprising: evaporating waste plastic by pyrolysis; bringing the obtained pyrolysis gas into contact with a gallium-containing silicate catalyst; and collecting a catalyst reaction product. 2. The method according to claim 1, wherein an H-type gallium silicate is used as the gallium-containing silicate. 3. A pyrolysis tank (2) for thermally decomposing and vaporizing waste plastics, and a catalytic reaction tank (3) for bringing the pyrolysis gas vaporized in the pyrolysis tank into contact with the gallium-containing silicate catalyst (8a). Waste plastic processing equipment characterized by comprising: 4. The waste plastic processing apparatus according to claim 3, wherein the catalytic reaction tank (3) is provided in a pyrolysis tank. 5. The waste plastics treatment according to claim 3, wherein the catalytic reaction tank (23) is provided outside the pyrolysis tank and the internal temperature can be set arbitrarily. apparatus. 6. The catalyst reactor (33) wherein the gallium-containing silicate catalyst (38a) is caused to flow by a pyrolysis gas. A waste plastic processing apparatus as described in the above.