JP3490671B2 - Method and apparatus for treating plastic waste containing halogen-containing plastic - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for treating plastic waste containing halogen-containing plastics, and its object is to obtain valuable waste such as styrene monomer that can be reused from plastic waste containing halogen-containing plastics. It is to promote the recycling of plastics for home appliances by making it possible to collect them at a rate.

[0002]

2. Description of the Related Art Conventionally, the disposal of used home electric appliances is collected and processed by municipalities as general waste, or it is taken to a store and crushed with shredders in whole,
Only some metals were sorted and collected as valuable resources. However, with the impending enforcement of the Specified Household Appliance Recycling Law (Home Appliance Recycling Law) for the purpose of promoting the recycling of used home appliances, we will make a full-scale effort to establish recycling technology for used home appliances. Is being promoted at a rapid pace, mainly in the home appliance industry. A major problem in recycling used home appliances is that plastic recycling technology is not yet well established. In particular, plastics for home electric appliances include polybrominated diphenyl ether (PBD) to prevent ignition.
E) and other brominated flame retardants are mixed, and this brominated flame retardant is generated as brominated dioxins with the same level of toxicity as dioxins when treating used home appliances, and it is harmful to the health of workers. There is concern about the danger of polluting the surrounding environment.

On the other hand, an apparatus for recovering styrene monomer from a commonly used polystyrene resin is
As shown in FIG. 6, a tank type reactor a for heating and decomposing polystyrene resin is provided, and the reactor a has a heating jacket b arranged around the reactor a and stirring for uniformly stirring the internal temperature. Means d, and if necessary, a catalyst for promoting decomposition is added. However, in such a conventional apparatus, the temperature of the inner wall of the reactor is always higher than the liquid temperature in the reactor because of the external heat type of heating by the heating jacket, and as a result, the temperature in the reactor becomes uneven. It became easy for carbon to adhere to the inner wall. If carbon adheres to the inner wall, the temperature of the inner wall will rise further, which will eventually lead to a decrease in heat transfer and the inability to operate due to coking, making continuous operation difficult. It was difficult to maintain a reaction temperature of at least 400 ° C. or higher, which is suitable for recovering the above. On the other hand, it is possible to use a catalyst to suppress the rise in the required reaction temperature, but since the activity of this type of catalyst deteriorates over time, in order to continue continuous operation, a continuous catalyst It is necessary to take out and supply equipment, which is also a technically difficult problem to solve.

In addition, in this type of external heating type reactor, the heat of decomposition required for the decomposition of the polystyrene resin is exchanged.
Although it is carried out through the decomposition residue accumulated in the tank, the styrene monomer as a solvent or the styrene monomer generated by the decomposition of polystyrene resin easily reacts with this decomposition residue and is converted into ethylbenzene, and the selectivity of the styrene monomer is increased. The inventors of the present application have confirmed a fatal drawback that the value is significantly reduced by continuous test equipment.
In other words, raising the reaction temperature required to recover styrene monomer in high yields causes problems in equipment and operation, increases the yield of decomposition residues, and further increases the yield of styrene monomer to ethylbenzene. This leads to a significant decrease in the recovery rate of the styrene monomer as a whole, and how to overcome these is a major problem of the conventional method.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and it is a plastic waste typified by used electric home appliances, especially containing halogen containing polystyrene as a main component. It is intended to provide a method and an apparatus for treating a plastic waste capable of continuously recovering valuable materials such as reusable styrene monomer from a plastic waste containing plastic at a high yield.

[0006]

The invention according to claim 1 is
After mixing a melt of a halogen-containing plastic containing polystyrene as a main component or a halogen-containing plastic containing polystyrene as a main component with a solvent containing a styrene monomer as a mixture with heating steam as a heat source such as reaction heat, This mixed fluid is supplied to a fixed bed reactor having an inner wall filled with a ceramic material, the resin is decomposed in the reactor, and the fluid taken out from the reactor is brought into contact with a metal catalyst to remove it. The present invention relates to a method for treating plastic waste, which comprises halogenating and then supplying it to a heating tank for further decomposition. The invention according to claim 2 is characterized in that the vapor generated in the heating tank is brought into contact with a catalyst to further decompose the polymer component contained in the vapor, thereby treating the plastic waste according to claim 1. Regarding the method. In the invention according to claim 3, after the steam generated in the heating tank is mixed with the heated steam, the mixed fluid is supplied to a fixed bed reactor having a packing inside to be contained in the steam. The method for treating plastic waste according to claim 1, wherein the polymer component is further decomposed in the reactor.

The invention according to claim 4 is mainly polystyrene.
A plastic waste containing a halogen-containing plastic to be a body is dissolved in N-methyl-2-pyrrolidone, undissolved material is removed from the obtained solution, and then N-methyl-2-pyrrolidone is separated and recovered from the solution. After mixing the remaining solution with heated steam as a heat source for heat of reaction, etc., the mixed fluid is supplied to a fixed bed reactor whose inner wall is filled with a ceramic material and the inside of the reactor is made of ceramic. The present invention relates to a method for treating plastic waste, which comprises decomposing halogenated by contacting a fluid that is decomposed and taken out from the reactor with a metal catalyst, and then supplies the heated fluid to a heating tank for decomposition. The invention according to claim 5 relates to the method for treating plastic waste according to any one of claims 1 to 4, wherein the filling material is an inert material having a high specific surface area. The invention according to claim 6 relates to the method for treating plastic waste according to any one of claims 1 to 4, wherein the packing is a catalyst. The invention according to claim 7 relates to the method for treating plastic waste according to any one of claims 1 to 6, characterized in that heated styrene monomer vapor is used in place of the heated steam.

The invention according to claim 8 is mainly polystyrene.
The melt or porosity of the halogen-containing plastic
A halogen-containing plastic containing styrene as a main component is dissolved in a solvent containing styrene monomer as a main component and mixed with heating steam or heated styrene monomer vapor as a heat source such as reaction heat, and a mixing means. The fixed-bed reactor that takes in the mixed fluid and decomposes it inside, the catalyst tank that brings the fluid taken out from the reactor into contact with the metal catalyst to dehalogenate, and heat the fluid that has passed through the catalyst tank. And a heating tank for further decomposing undecomposed material in the reactor, to a plastic waste processing apparatus. According to a ninth aspect of the present invention, a plastic waste containing a halogen-containing plastic whose main component is polystyrene is N-.
A dissolution tank for dissolving in methyl-2-pyrrolidone,
A removing means for removing the undissolved matter from the solution taken out from the dissolution tank; a separation and recovery means for separating and recovering N-methyl-2-pyrrolidone from the solution from which the undissolved matter has been removed by the removing means; -Mixing means for mixing the remaining solution from which methyl-2-pyrrolidone has been separated with heated steam or heated styrene monomer vapor as a heat source for heat of reaction and the like, and introducing the mixed fluid obtained by the mixing means into the inside. A fixed bed reactor that decomposes, a catalyst tank that dehalogenates a fluid taken out from the reactor by contacting it with a metal catalyst, and a fluid that has passed through the catalyst tank is heated to remove undecomposed substances in the reactor. The present invention relates to an apparatus for treating plastic waste, which further comprises a heating tank for decomposing. The invention according to claim 10 relates to the apparatus for treating plastic waste according to claim 8 or 9, characterized in that the inner surfaces of the mixing means, the fixed bed reactor and the catalyst tank are made of ceramics.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of a method and apparatus for treating plastic waste containing halogen-containing plastic according to the present invention will be described below with reference to the drawings. FIG. 1 is a schematic flow chart showing the first embodiment of the present invention. In the present invention, a plastic waste represented by used home appliances, specifically, a halogen-containing plastic mainly composed of polystyrene is used as a raw material, and the raw material (A) is a screw feeder (extruder).
Is supplied in the form of a melt that is heated and melted by, or in the form of a solution dissolved in a solvent containing a styrene monomer as a main component.

The raw material (A) supplied in the above form is
400 to 700 ° C., for example 500 by the mixing means (1)
It is mixed with heated steam (SHS) at 0 ° C. and fed to the fixed bed reactor (2) at 250 ° C. or higher, which is sufficient to obtain the fluidity of the polystyrene resin. At this time, when the raw material is supplied in the form of a solution, most of the styrene monomer used as a solvent is vaporized. The structure of the mixing means (1) is not particularly limited, and for example, a heating steam supply pipe and a mixing pipe connected to the supply pipe for mixing the raw materials can be used. The inner wall of the mixing means (1) is made of ceramic, which prevents corrosion by halogen and enables continuous operation for a long period of time.
In the present invention, it is also possible to adopt a configuration in which heated styrene monomer vapor is mixed by the mixing means (1) instead of the heated steam. In this case, the temperature of the heated styrene monomer vapor is 400 to 700 ° C, for example 500 ° C.

As the fixed bed reactor (2), a fixed bed system having a packed bed of a catalyst or an inert packing having a large specific surface area (for example, ceramic Raschig rings or ball rings) is adopted, and a molten resin is used. Is formed into a thin film on the catalyst or the packing, and is decomposed by a high temperature of at least 250 ° C. or higher, preferably 400 to 450 ° C., which is given by the heated steam or heated styrene monomer vapor, to produce a styrene monomer. To be done. The inner wall of the fixed bed reactor (2) is also made of ceramic so that the inside of the reactor is prevented from being corroded by halogen.

As described above, when an internal heat type is used in which heated steam is used to supply heat of reaction and the like, a mixed gas in the fixed bed reactor (2) (heated steam, styrene monomer, and polystyrene resin decomposition product) is mixed. The flow rate of the mixed gas) is high, so that the contact time between the styrene monomer and the decomposition residue is shortened, and the conversion of the styrene monomer into ethylbenzene can be suppressed sufficiently low. The operating pressure of this reaction system is preferably in the range of absolute pressure 0.04 to 0.3 MPa. Further, in order to bring the outlet temperature of the fixed bed reactor (2) to a desired temperature,
The required amount of heated steam or heated styrene monomer vapor may be separately supplied to the inlet of the reactor (2).

In the present invention, the catalyst used as the packed bed of the fixed bed reactor (2) is not particularly limited, but sodium sulfate, iron sulfate, manganese sulfate, zinc sulfate, aluminum sulfate, calcium sulfate, potassium sulfate, Sulfates such as antimony sulfate and manganese dioxide are preferably used. These catalysts have relatively low temperatures (below 350 ° C)
This is because the polystyrene resin can be catalytically decomposed by the method, and the amount of low molecular weight components contained in the catalytic decomposition product can be reduced. Further, since these catalysts are relatively inexpensive and easily available, there is an advantage that the catalyst cost can be reduced.

In the present invention, the polystyrene resin may be pyrolyzed in the fixed bed reactor (2) without using a catalyst. At this time, the temperature of the heated steam or heated styrene monomer vapor mixed in the mixing means (1) is higher than that when a catalyst is used, and is appropriately set in order to maintain a predetermined reaction temperature in the range of 400 to 600 ° C. . In this case, a layer of inert packing having a large specific surface area, such as ceramic Raschig rings or ball rings, is provided in the reactor (2) for thermal decomposition. The operating pressure is preferably in the range of 0.04 to 0.3 MPa absolute pressure.

Further, as shown in FIG. 2, two or more fixed bed reactors (2) are connected in parallel, and one fixed bed reactor (2) is selectively operated by the operation of the valve (3). This may be done so that another fixed bed reactor (2) can be used at the time of opening, inspection and repair of the reactor (2), and long-term continuous operation becomes possible.

The fluid that has passed through the fixed bed reactor (2) is then fed to the catalyst tank (4). In the catalyst tank (4),
Metal catalysts such as iron, iron catalysts, zinc, aluminum, copper, and nickel are filled, and the fluid supplied from the fixed bed reactor (2) is dehalogenated by contacting these metal catalysts. The bromine component contained in the raw material polystyrene resin is FeBr ₂ or FeBr
It becomes ₃ and is taken out from the bottom of the catalyst tank (4). At this time, the chlorine component contained in the raw material is also removed at the same time as, for example, FeCl ₃ .

The fluid dehalogenated by passing through the catalyst tank (4) is dropped and supplied to the heating tank (5), and in this heating tank (5), a heating jacket (5a) and a stirring blade (5b). Is heated and decomposed with the operation of. The decomposition residue is finally discharged from the bottom of the heating tank (5). It is preferable that the inner surface of the catalyst tank (4) is also made of ceramic in order to prevent corrosion due to halogen. On the other hand, the mixed gas that has passed through the catalyst tank (4) and the vapor generated by thermal decomposition in the heating tank (5) are then condensed in the condenser (6).
And is condensed and liquefied. When heated steam is used, the condensed and liquefied liquid contains a large amount of water obtained by liquefaction in the heated steam in addition to the crude styrene monomer which is a decomposition product. And the crude styrene monomer and water are separated. Although the structure of the separator (7) is not particularly limited, for example, a liquid capable of recovering the crude styrene monomer can be adopted as the supernatant liquid passing over the separation wall (7a) as shown in the figure.

FIG. 3 is a schematic flow chart showing the second embodiment of the present invention. The difference between the second embodiment and the first embodiment is that a catalyst tank (8) is provided between the heating tank (5) and the condenser (6), and thermal decomposition is performed in the heating tank (5). The point is that the steam generated by the above is introduced to the condenser (6) after passing through the catalyst tank (8).
Since the configuration other than this is the same as that of the first embodiment,
The same components are designated by the same reference numerals and description thereof will be omitted.

The catalyst tank (8) is filled with a catalyst for catalytically decomposing the polymer component contained in the steam generated in the heating tank (5). The type of the catalyst is not particularly limited, but sulfates such as sodium sulfate, iron sulfate, manganese sulfate, zinc sulfate, aluminum sulfate, calcium sulfate, potassium sulfate, antimony sulfate, and manganese dioxide are preferably used.

According to this second embodiment, the heating tank (5)
By passing the steam generated in step 2 through the catalyst tank (8), the polymer component contained in the steam is further decomposed and converted into styrene monomer, and the crude styrene monomer recovered in the separator (7) is added. It is possible to further increase the ratio of the included styrene monomer.

FIG. 4 is a schematic flow chart showing the third embodiment of the present invention. The third embodiment is different from the first embodiment in that a heating steam mixing means (9) and a fixed bed reactor (10) are provided between the heating tank (5) and the condenser (6). That is the point. That is, according to this embodiment,
At least 250 ° C., in which heating steam is mixed with the steam generated by thermal decomposition in the heating tank (5) and introduced into the fixed bed reactor (10) and given by the heating steam in the reactor (10). Or more, preferably 400 to 4
A styrene monomer is produced by decomposition at a high temperature of 50 ° C. It is also possible to employ a configuration in which heated styrene monomer vapor is mixed by the mixing means (9) instead of the heated steam. In this case, the temperature of the heated styrene monomer vapor is 400 to 700 ° C, for example 500 ° C.
It is said that

As the fixed bed reactor (10), as in the fixed bed reactor (2) described in the first embodiment, a packed bed of catalyst or packing having a high specific surface area (for example, ceramic Raschig rings). The fixed-bed method with is adopted. Since the other configurations are the same as those in the first embodiment, the same configurations are denoted by the same reference numerals and the description thereof will be omitted.

According to this third embodiment, the heating tank (5)
When high-temperature heated steam or heated styrene monomer vapor is mixed with the vapor generated in step 1, the polymer component contained in the vapor taken out from the heating tank (5) is further decomposed and converted into styrene monomer. Then, the ratio of the styrene monomer contained in the crude styrene monomer recovered by the separator (7) can be further increased.

The embodiment described above is very effective when the supplied raw material is only polystyrene resin, but in reality, only polystyrene resin is selected from the discharged plastic waste and used as the raw material. It is difficult to supply, and in many cases, different kinds of synthetic resins such as polyethylene, polypropylene and ABS resin are mixed in the raw materials. Therefore, the inventors of the present application newly created a raw material selection step for selecting different synthetic resins such as polystyrene and polyethylene, polypropylene, and ABS resin in the preceding step supplied to the above embodiment.

FIG. 5 is a schematic flow chart of the raw material selecting step used in the present invention. As described above, this raw material selecting step is supplied to the processing steps shown in the first to third embodiments. It is a pre-process for obtaining raw materials. In this raw material selection step, halogen-containing plastics containing polystyrene as the main component are added to polyethylene, polypropylene, A
Plastic waste mixed with different synthetic resins such as BS resin is used as the raw material, and these raw materials are first crusher (11).
After being crushed to a certain size or smaller, it is once stored in the storage tank (12). And with respect to the raw material stored in this storage tank (12), N-methyl-2-
Pyrrolidone (hereinafter abbreviated as NMP) is supplied, and the raw material is sent to the dissolution tank (14) by the transport conveyor (13) together with the supplied NMP, and heated and stirred in the dissolution tank (14). While being selectively dissolved.

The main reason why NMP is used as a solvent for the raw material resin in the present invention is that NMP dissolves polystyrene very well, but polyethylene, polypropylene,
ABS resin has a dissolution characteristic of being almost insoluble. Furthermore, NMP has a heat of vaporization of 105 kcal / kg: 20
Since it is as low as 4 ° C, distillation can be performed with low energy, which is economical. Since the evaporation temperature is as high as 204 ° C, it is possible to clear the regulation value concerning VOC (volatile hydrocarbons) of the local government environmental regulations. Yes (for example, the Osaka Prefectural Ordinance regulates that hydrocarbons have a regulated value of "boiling point is 150 ° C alone
The following substances and mixtures have a 5% distillation point of 150 ° C. or less ”) and have extremely low toxicity. These properties also use NMP as a solvent in the present invention. That's why.

The solution obtained in the dissolution tank (14) is sent to the separator (16) by the pump (15).
The separation device (16) plays a role as a removal means for removing undissolved substances in the solution, and a centrifugal separator, a filtration device or the like can be preferably used. In the separator (16), different synthetic resins such as polyethylene, polypropylene and ABS resin which are not dissolved in NMP are separated and removed from the solution, and the removed product is stored in a storage tank (17) and used as a raw material for solid fuel or liquid fuel. Used for reuse.

The solution from which the different synthetic resin has been removed is sent to the distillation apparatus (19) by the pump (18). The distillation device (19) plays a role as a separation and recovery means for separating and recovering NMP from the solution, and may be either a vacuum distillation device or an atmospheric distillation device. The NMP separated by the distillation apparatus (19) is condensed and liquefied by the condenser (20) and then stored in the NMP storage tank (21) for reuse. Then, the raw material after NMP is separated is once stored in the storage tank (22), and then sent to the extruder (24) by the pump (23), and the temperature of 200 ° C. or higher is supplied by the extruder (24). It is supplied as a raw material (A) in the steps of the first to third embodiments in the softened state.

By providing the above-mentioned raw material selection step, a polystyrene-rich raw material can be obtained from a raw material in which different kinds of synthetic resins are mixed. Therefore, by using this raw material, the first to third embodiments are shown. It is possible to increase the yield of the styrene monomer that is finally recovered in the subsequent step.

When polyvinyl chloride (PVC) or polyvinylidene fluoride (PVdF) is contained in the raw material, these resins are also dissolved in NMP together with polystyrene and supplied as a raw material to the subsequent step. However, in the present invention, since dehalogenation can be performed in the subsequent step, there is no problem in processing.

[0031]

EXAMPLES The effects of the present invention will be made clearer by showing Examples and Comparative Examples of the present invention. However, the present invention is not limited to the following examples. Example 1 Using the apparatus shown in FIG. 1, a raw material made of a polystyrene resin (bromine content of 4.5 wt%) containing a brominated flame retardant was treated by the method described below. 2.0 kg / h (60 to 70 ° C.) of a solution prepared by dissolving the raw material in 3 times the weight of the styrene monomer, and heated steam 2
5 kg / h (480 to 490 ° C.) was mixed and sent to a fixed bed reactor (packing: Raschig ring) to decompose polystyrene (PS). The temperature in the fixed bed reactor is 420 ~
The pressure was 430 ° C., the pressure was 0.01 MPaG, and Fe ₂ O ₃ was used as the metal catalyst filled in the catalyst tank (4). The amount of crude styrene monomer recovered in the separator was 1980 g / h, and when the styrene monomer used as the solvent was subtracted, it was 480 g / h (recovery rate: 96
wt%). The yield of decomposition residue (relative to PS) was 1.0 wt%. As a result of analyzing the obtained crude styrene monomer by gas chromatography (solvent styrene monomer correction), the content ratio of styrene monomer was 7
6.5 wt%, dimer, trimer content is 20.24
%, And the bromine content was 0.001 wt%.

Example 2 Using the apparatus shown in FIG. 3,
A raw material made of a polystyrene resin containing bromine flame retardant (bromine content: 4.5 wt%) was treated under the same conditions as in Example 1 except that the catalyst tank (8) was filled with a catalyst made of magnesium sulfate. . The amount of crude styrene monomer recovered in the separator was 1960 g / h, and when the styrene monomer used as the solvent was subtracted, it was 460 g / h.
It was h (recovery rate: 92 wt%). The yield of decomposition residue (relative to PS) was 1.0 wt%. As a result of analyzing the obtained crude styrene monomer by gas chromatography (solvent styrene monomer correction), the content of styrene monomer was 98.5 wt% and the content of bromine was 0.001.
It was wt%.

(Example 3) Using the apparatus shown in FIG.
A raw material made of a polystyrene resin containing a brominated flame retardant (bromine content: 4.5 wt%) was treated. The heated steam mixed by the mixing means (9) is 25 kg / h (4
80 to 490 ° C.), the packing of the fixed bed reactor (10) was Raschig ring, and the temperature in the reactor was 420 to 43.
Example 1 except that the temperature was 0 ° C. and the pressure was 0.01 MPaG.
The same conditions were used. The amount of crude styrene monomer recovered in the separator was 1980 g / h, and when the styrene monomer used as the solvent was subtracted, it was 480 g / h.
(Recovery rate: 96 wt%). The yield of decomposition residue (relative to PS) was 1.0 wt%. As a result of analyzing the obtained crude styrene monomer by gas chromatography (solvent styrene monomer correction), the content of styrene monomer was 96.0 wt% and the content of bromine was 0.001 w.
It was t%.

Comparative Example Using a conventional tank reactor as shown in FIG. 6, a raw material made of polystyrene resin (bromine content 4.5% by weight) containing a brominated flame retardant was treated. It was 2.5 kg / h (60 to 70) of a solution prepared by dissolving polystyrene resin in four times the amount of styrene monomer
(° C) to the reactor for thermal decomposition. The temperature inside the reactor was 380 ° C. and the pressure was 0.001 MPaG. As a result of analyzing the obtained crude styrene monomer by gas chromatography (without solvent styrene monomer correction), the content of styrene monomer was 78.0 wt%, and the amount of recovered styrene monomer was higher than that of the styrene monomer used as the solvent. It was decreasing. The ethylbenzene content is 18.6 wt% and the bromine content is 4.5.
It was wt%.

[0035]

As described above, according to the method and apparatus of the present invention, it is possible to recover the styrene monomer by dehalogenating the plastic waste containing the halogen-containing plastic mainly composed of polystyrene. It is possible to promote recycling of plastics for home appliances that contain brominated flame retardants, and to decompose resin such as polystyrene by internal heat by using heated steam or heated styrene monomer vapor as a reaction heat source. Can be set to a high temperature, and as a result, it has become possible to select a condition in which almost no decomposition residue is produced. In addition, the decomposition products of polystyrene instantly move to the heating vapor phase, and the contact time between the decomposition residue of polystyrene resin and styrene monomer can be shortened and the conversion to ethylbenzene is suppressed. It is possible to recover various styrene monomers with high yield, high selectivity and high purity. Furthermore, by making the mixing means, the fixed bed reactor and the inner wall of the catalyst tank made of ceramic,
Corrosion inside the reactor due to halogen separated from the plastic waste raw material was prevented, and continuous operation for a long time became possible. Further, by dissolving a plastic waste containing a halogen-containing plastic mainly composed of polystyrene in N-methyl-2-pyrrolidone, a polystyrene-rich raw material can be obtained from a raw material mixed with a different synthetic resin such as polyethylene or polypropylene. Therefore, the yield of the finally recovered styrene monomer can be further increased.

[Brief description of drawings]

FIG. 1 is a schematic flowchart showing a first embodiment of the present invention.

FIG. 2 is a schematic view showing a form in which two fixed bed reactors are installed in parallel.

FIG. 3 is a schematic flow chart showing a second embodiment of the present invention.

FIG. 4 is a schematic flow chart showing a third embodiment of the present invention.

FIG. 5 is a schematic flow diagram of a raw material selection process used in the present invention.

FIG. 6 is a schematic diagram showing a conventional technique.

[Explanation of symbols]

1 mixing means 2 fixed bed reactor 4 catalyst tank 5 heating tanks 8 catalyst tanks 9 Mixing means 10 fixed bed reactor

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Claims (10)

(57) [Claims] 1. A melt of a halogen-containing plastic containing polystyrene as a main component or a polystyrene containing as a main component
That after the halogen-containing plastic is dissolved in a solvent mainly composed of styrene monomer solution was mixed with heating steam as a heat source, such as the reaction heat, the inner wall made of ceramic containing the packing the mixed fluid inside It is characterized in that it is supplied to a fixed bed reactor to decompose the resin in the reactor, the fluid taken out from the reactor is brought into contact with a metal catalyst to dehalogenate, and then supplied to a heating tank for further decomposition. And the method of treating plastic waste. 2. The method for treating plastic waste according to claim 1, wherein the steam generated in the heating tank is brought into contact with a catalyst to further decompose the polymer component contained in the steam. 3. The steam generated in the heating tank is mixed with heated steam, and then the mixed fluid is supplied to a fixed bed reactor having a packing inside, and the polymer component contained in the steam is supplied. The method for treating plastic waste according to claim 1, further comprising decomposing the above in the reactor. 4. A plastic waste containing halogen-containing plastic mainly composed of polystyrene is treated with N-methyl-.
After dissolving in 2-pyrrolidone and removing undissolved matter from the obtained solution, N-methyl-2-pyrrolidone is separated and recovered from the solution, and the remaining solution is mixed with heated steam as a heat source such as heat of reaction. After that, this mixed fluid is supplied to a fixed bed reactor having an inner wall filled with a filler and made of ceramic to decompose in the reactor, and the fluid taken out from the reactor is contacted with a metal catalyst. A method for treating plastic waste, which comprises dehalogenating and dehalogenating it and then supplying it to a heating tank for decomposition. 5. The method for treating plastic waste according to claim 1, wherein the filling material is an inert material having a high specific surface area. 6. The method for treating plastic waste according to any one of claims 1 to 4, wherein the packing is a catalyst. 7. The method for treating plastic waste according to claim 1, wherein heated styrene monomer vapor is used in place of the heated steam. 8. A polystyrene-based halogen-containing plastic melt or polystyrene
That halogen and mixing means containing plastic is mixed to the heating steam or heating styrene monomer vapor of a solution dissolved in a solvent mainly composed of a styrene monomer as a heat source, such as the reaction heat, the mixed fluid obtained in the mixing means In a fixed bed reactor for decomposing by taking in, a catalyst tank for dehalogenating a fluid taken out from the reactor by contacting the metal catalyst, and a fluid passing through the catalyst tank for heating in the reactor. And a heating tank for further decomposing the undecomposed material of (1) above. 9. A plastic waste containing a halogen-containing plastic mainly composed of polystyrene is treated with N-methyl-.
A dissolution tank for dissolving in 2-pyrrolidone, a removal means for removing undissolved substances from the solution taken out from the dissolution tank, and a solution N-
Separation and collection means for separating and collecting methyl-2-pyrrolidone, and mixing means for mixing the remaining solution from which N-methyl-2-pyrrolidone has been separated with heated steam or heated styrene monomer vapor as a heat source such as reaction heat, A fixed bed reactor that takes in the mixed fluid obtained by the mixing means inside and decomposes it, a catalyst tank that brings the fluid taken out from the reactor into contact with a metal catalyst to dehalogenate it, and pass through the catalyst tank And a heating tank for further decomposing undecomposed substances in the reactor by heating the fluid. 10. The apparatus for treating plastic waste according to claim 8 or 9, wherein the mixing means, the fixed bed reactor, and the inner surface of the catalyst tank are made of ceramics.