KR102601709B1 - Waste plastic pyrolysis apparatus - Google Patents

Abstract

A thermal decomposition device for waste plastic according to exemplary embodiments of the present invention includes a preprocessing unit for preprocessing cut and pulverized waste plastic; and a pyrolysis reactor for pyrolyzing the pretreated waste plastic, wherein the pretreatment unit includes a storage tank for storing the cut and pulverized waste plastic in a molten slurry state. and a hopper unit for supplying the waste plastic in the molten slurry state to the pyrolysis reactor, wherein the pretreatment unit is composed of a plurality of storage tanks and a plurality of hopper units that are driven alternately, and preprocesses the waste plastic. The process is controlled to be performed continuously.

Description

Waste plastic pyrolysis apparatus}

The present invention relates to a pyrolysis device for waste plastic, and more specifically, to a pyrolysis device for waste plastic that can increase the pyrolysis yield of waste plastic and prevent leakage of flammable and malodorous substances.

With the industrial revolution and the development of the petrochemical industry, mankind has sought convenience by manufacturing and producing various polymer compounds and applying them to daily life. However, the disposal of waste due to industrial development for the convenience of life is a problem that each country is currently struggling with, and only a small portion of products made from synthetic resins such as tires, vinyl, and plastic, which are widely used in various industrial fields and daily life, are used. It is recycled, but most of it is classified as waste and is landfilled or incinerated.

Plastic waste such as synthetic resin is considerably larger in volume compared to its weight, so landfill costs are higher than general waste, and it does not rot even when landfilled, so it is dismissed as a social nuisance. In particular, the recycling rate of waste plastic is low compared to other waste. Specifically, in Korea in 2005 alone, the recycling rate for waste paper was 55%, used tires were 67%, glass bottles were 58%, and scrap metal was 43%, while plastics were only at 15%. Moreover, 4 to 5 million tons of waste plastic are generated every year, and the amount of waste plastic is also increasing significantly every year.

Methods for disposing of these combustible wastes include recycling and use, or incineration and landfill. However, due to limitations in the materials to be recycled, in the case of incineration, dust, hydrogen chloride (HCl), sulfur oxides (SOx), and nitrogen oxides ( The problem of secondary air pollution due to the emission of air pollutants such as NOx) and dioxin is serious, and even in the case of landfill, pollution problems due to soil pollution and leachate due to the non-decomposability characteristic of combustible waste are serious.

Accordingly, research and development of emulsification methods and devices that can obtain useful oil by pyrolyzing combustible waste is being actively conducted as a way to recycle combustible waste without incinerating or landfilling.

Registered Patent Publication No. 10-1890415 (announcement date: August 21, 2018) discloses a waste plastic pyrolysis emulsification device that reduces and recovers recycled oil from waste plastic through pyrolysis. At this time, useful oil can be obtained by heating the waste plastic in a sealed reactor and condensing the gas generated through an endothermic reaction.

However, due to the nature of the pyrolysis furnace for gas extraction, it is sealed to the outside, so once the extraction process is completed with the input waste plastic, it has to be cooled, the residue is discharged, and the waste plastic must be input and reheated, so the efficiency is bound to be quite low, and condensation from the obtained gas is necessary. Gas that remains until the end must be removed by incineration unless there is a separate storage facility, making it difficult to obtain a high yield due to the waste of useful substances.

In particular, in order to prevent an explosive reaction from occurring when the hydrogen generated inside the pyrolysis furnace meets the surrounding air during the process of inputting waste plastic, a process in which the hydrogen inside the pyrolysis furnace is removed and the temperature is cooled is necessary, so in a conventional pyrolysis furnace, There is also the problem that continuous supply of waste plastic cannot be achieved, so the yield is inevitably extremely low.

Additionally, if the waste plastic is in the form of a pouch or flexible container, it must be slowly cooled after the pyrolysis process. Failure to go through this cooling process may lead to explosion. Waste plastics may contain various types of items, and among them, there may be pouch-shaped items, so to prevent safety accidents such as explosions, a long period of cooling is required after a single pyrolysis process, so conventional pyrolysis furnaces have low yield. There is a problem that this cannot help but be low.

Registered Patent Publication No. 10-1890415 (Publication date: 2018.08.21)

One of the various tasks of the present invention is to provide a pyrolysis device for waste plastic that can increase the pyrolysis yield of waste plastic by controlling the pre-treatment unit to be continuously performed in a pre-treatment unit consisting of a plurality of storage tanks and a plurality of hopper units. It is done.

One of the various tasks of the present invention is to provide a pyrolysis device for waste plastic that can prevent safety accidents such as explosions by blocking the leakage of flammable pyrolysis gas by supplying inert gas to the inside of the storage tank through an inert gas supply unit connected to the storage tank. It is provided.

One of the various tasks of the present invention is to install a mechanical seal in the hopper unit, the pyrolysis tank, and the first and second rotary valves to prevent leakage of pyrolysis gas, and to inject an inert fluid into at least a part of the sealing member. The aim is to provide a pyrolysis device for waste plastic that can prevent safety accidents such as explosions by blocking leakage of flammable pyrolysis gas by installing an inert fluid supply unit for supply.

A thermal decomposition device for waste plastic according to exemplary embodiments of the present invention includes a preprocessing unit for preprocessing cut and pulverized waste plastic; and a pyrolysis reactor for pyrolyzing the pretreated waste plastic, wherein the pretreatment unit includes a storage tank storing the cut and pulverized waste plastic in a molten slurry state. and a hopper unit for supplying the waste plastic in the molten slurry state to the pyrolysis reactor, wherein the pretreatment unit is composed of a plurality of storage tanks and a plurality of hopper units that are driven alternately, and preprocesses the waste plastic. The process can be controlled to be performed continuously.

The preprocessing unit may include a first preprocessing unit consisting of a first storage tank and a first hopper unit connected thereto, and a second preprocessing unit consisting of a second storage tank and a second hopper unit connected thereto, and the supply of the cut and pulverized waste plastic may be performed. It may be controlled to be performed alternatively for the first storage tank or the second storage tank.

The pretreatment unit may further include a pyrolysis oil supply unit connected to the storage tank to supply pyrolysis oil of high temperature and high boiling point.

The pretreatment unit may further include an inert gas supply unit connected to the storage tank to supply an inert gas.

The hopper unit may include a first flow tube providing a space through which the waste plastic in the molten slurry state flows, and a second flow tube covering the first flow tube from the outside and providing a space through which the heating source flows. You can.

The hopper unit includes a first rotating shaft extending through the first flow pipe, a transfer screw coupled to the first rotating shaft and installed inside the first flow pipe and flowing the waste plastic in the molten slurry state, and the It may further include a first rotation shaft drive motor that is coupled to the first rotation shaft and installed outside the first flow pipe and supplies rotational force to the first rotation shaft.

A mechanical seal is installed on the outer surface of the first flow pipe penetrated by the first rotation shaft to prevent leakage of internal gas, and an inert fluid is supplied to at least a portion of the sealing member. A supply unit may be installed.

The pyrolysis reactor may be comprised of a continuous stirred-tank reactor (CSTR).

The pyrolysis reactor includes a pyrolysis tank that stores the pretreated waste plastic and provides a space where pyrolysis is performed; a heating source supply unit that covers the pyrolysis tank from the outside and supplies a heating source; and a stirring unit installed inside the pyrolysis tank to stir the waste plastic.

The stirring unit includes a second rotation shaft extending through the upper surface of the pyrolysis tank, a stirring member coupled to the second rotation shaft and installed inside the pyrolysis tank and stirring the waste plastic, and a second rotation shaft. It may be installed outside the pyrolysis tank and include a second rotation shaft drive motor that supplies rotational force to the second rotation shaft, and the outer surface of the pyrolysis tank penetrated by the second rotation shaft is to prevent leakage of internal gas. A mechanical seal may be installed, and an inert fluid supply unit for supplying an inert fluid may be installed on at least a portion of the sealing member.

a residue storage tank connected to the pyrolysis tank to provide a space for storing residue; and

It may further include a first rotary valve installed in the flow path between the pyrolysis tank and the residue storage tank to control the flow of residue, wherein the first rotary valve has a sealing member to prevent leakage of internal gas. (Mechanical Seal) may be installed, and an inert fluid supply unit for supplying an inert fluid may be installed on at least a portion of the sealing member.

a residue discharge unit connected to the residue storage tank to discharge residue; and a second rotary valve installed in the passage between the residue storage tank and the residue discharge unit to control discharge of the residue, wherein the second rotary valve is configured to prevent leakage of internal gas. A mechanical seal may be installed, and an inert fluid supply unit for supplying an inert fluid may be installed on at least a portion of the sealing member.

Each feature of the above-described embodiments can be implemented in combination in other embodiments as long as it is not contradictory or exclusive to other embodiments.

According to various embodiments of the present invention, the pyrolysis device for waste plastic can continuously perform the pretreatment process through the pretreatment part of the dual system, thereby increasing the pyrolysis yield of waste plastic and preventing leakage of combustible pyrolysis gas generated during the pyrolysis process. It has the effect of preventing safety accidents such as explosions by blocking it through a sealing member (mechanical seal) and the supply of inert gas or fluid.

The effects of the present invention are not limited to those described above, and other effects not mentioned will be clearly recognized by those skilled in the art from the description below.

Figure 1 is a flow chart of a pyrolysis process using a pyrolysis device for waste plastic according to the present invention.
Figure 2 is a diagram showing the pretreatment section of the thermal decomposition device for waste plastic according to the present invention.
Figure 3 is a diagram showing the thermal decomposition reactor and residue treatment unit of the thermal decomposition device for waste plastic according to the present invention.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. The detailed description below is provided to provide a comprehensive understanding of the methods, devices and/or systems described herein. However, this is only an example and the present invention is not limited thereto.

In describing the embodiments of the present invention, if it is determined that a detailed description of the known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. In addition, the terms described below are terms defined in consideration of functions in the present invention, and may vary depending on the intention or custom of the user or operator. Therefore, the definition should be made based on the contents throughout this specification. The terminology used in the detailed description is merely for describing embodiments of the present invention and should in no way be limiting. Unless explicitly stated otherwise, singular forms include plural meanings. In this description, expressions such as “comprising” or “comprising” are intended to indicate certain features, numbers, steps, operations, elements, parts or combinations thereof, and one or more than those described. It should not be construed to exclude the existence or possibility of any other characteristic, number, step, operation, element, or part or combination thereof.

Additionally, in describing the components of the embodiment of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are only used to distinguish the component from other components, and the nature, sequence, or order of the component is not limited by the term.

Below, the pyrolysis process using the pyrolysis device for waste plastic according to the present invention will be briefly described with reference to the drawings.

Figure 1 is a flow chart of a pyrolysis process using a pyrolysis device for waste plastic according to the present invention.

Referring to Figure 1, the pyrolysis process using the pyrolysis device for waste plastic according to the present invention may include a pretreatment process (S10), a pyrolysis process (S20), and a residue treatment process (S30).

First, the waste plastic cut and pulverized in the pretreatment process (S10) is input into the storage tank 11, melted by pyrolyzed heavy oil, and slurryed by the screw device of the hopper unit 13. can be transported.

Waste plastic in a slurry state melted through the pretreatment process (S10) is supplied to the thermal decomposition reactor (20) to perform the thermal decomposition process (S20).

In the pyrolysis process (S20), the waste plastic in the slurry state pretreated is pyrolyzed to generate waste plastic oil vapor. The waste plastic oil vapor is discharged to the outside of the pyrolysis reactor 20 by the waste plastic oil vapor discharge unit 80 and undergoes dechlorination process and then undergoes pyrolyzed oil vapor condensation. It may be condensed through the process to form liquid pyrolysis oil.

Flue gas can be used as a heat source for the pretreatment process (S10) and the pyrolysis process (S20). The combustion flue gas can be used as a heat source and then reused, or it can be supplied to a flue gas cooler, cooled, and then purified to separate carbon dioxide (CO ₂ ) and then discharged into the atmosphere. Additionally, carbon dioxide (CO ₂ ) can be used to prevent leakage of combustible gas within a pyrolysis device.

Residue remaining unreacted in the thermal decomposition process (S20) may be discharged to the outside of the thermal decomposition device through the residue treatment process (S30).

Meanwhile, combustible gas may be generated inside the pyrolysis device through the pretreatment process (S10), the pyrolysis process (S20), and the residue treatment process (S30). If the combustible gas leaks, it may cause an explosive reaction when it meets oxygen in the air, which may result in a safety accident. Therefore, in each process, carbon dioxide (CO ₂ ) is supplied to the inside of the pyrolysis device at a predetermined pressure to prevent combustible gas from leaking.

Hereinafter, the thermal decomposition device for waste plastic according to the present invention will be described in detail with reference to the drawings.

Figure 2 is a diagram showing the pretreatment unit of the pyrolysis device for waste plastic according to the present invention, and Figure 3 is a diagram showing the pyrolysis reactor and residue treatment section of the pyrolysis device for waste plastic according to the present invention.

Referring to Figures 2 and 3, the pyrolysis device for waste plastic according to the present invention includes a pretreatment unit 10 for preprocessing waste plastic and a pyrolysis reactor 20 for pyrolyzing the pretreated waste plastic. may include.

The waste plastic is preferably supplied to the pretreatment unit 10 in a cut and shredded state, and may be a mixture of thermoplastic resin, thermosetting resin, and polyvinyl chloride (PVC). However, the concept of the present invention is not necessarily limited to this, and the waste plastic may be supplied to the preprocessing unit 10 in a state that is not cut or shredded.

As an example, the waste plastic is preferably mixed in a ratio of 70 wt% or less of thermoplastic resin, 20 wt% or more of thermosetting resin, and 10 wt% or more of polyvinyl chloride (PVC), but according to the present invention, The concept is not necessarily limited to this.

Referring to FIG. 2, the pretreatment unit 10 according to the present invention includes a storage tank 11 and a hopper unit 13, and the cut and pulverized waste plastic is stored at high temperature and high boiling point in the storage tank 11. It is mixed with pyrolyzed heavy oil and stored in a molten slurry state, and the waste plastic in the molten slurry state can be supplied to the pyrolysis reactor 20 through the hopper unit 13.

More specifically, the storage tank 11 may have a shape whose width becomes smaller from the top to the bottom. The upper part forms an inlet into which cut and pulverized waste plastic can be input, and the lower part forms a slurry-state waste plastic. An outlet can be formed through which waste plastic can be discharged. In addition, mechanical devices for sealing may be included at the top and bottom of the storage tank 11 to maintain the sealed state when the melted waste plastic is stored inside the storage tank 11.

The pyrolyzed heavy oil can be supplied to the storage tank 11 through the pyrolysis oil supply unit 50 connected to the storage tank 11, and the cut and pulverized waste plastic inside the storage tank 11. ) is melted into a slurry state and serves to maintain the melted waste plastic in a slurry state.

When the cut and pulverized waste plastic is melted by the pyrolyzed heavy oil, flammable pyrolysis gas may be generated inside the storage tank 11.

It is desirable that the storage tank 11 is maintained in a basically sealed state to prevent the pyrolysis gas from leaking into the air. However, when the melted waste plastic is discharged to the hopper part 13 connected to the lower part of the storage tank 11 and new cut and pulverized waste plastic is supplied through the upper part of the storage tank 11, the storage tank 11 is sealed. There is a risk that flammable pyrolysis gas may leak into the atmosphere if the condition is lifted.

If the flammable pyrolysis gas leaks into the atmosphere, an explosive reaction may occur and a safety accident may occur. Therefore, the pretreatment unit 10 of the waste plastic pyrolysis device according to the present invention may further include an inert gas supply unit 60 connected to the storage tank 11 to supply an inert gas.

The inert gas supplied through the inert gas supply unit 60 may be carbon dioxide (CO ₂ ), but the present invention is not necessarily limited, and other known inert gases may be adopted.

When the inert gas is supplied, a predetermined pressure is applied to the pyrolysis gas present inside the storage tank 11, thereby preventing the pyrolysis gas from leaking out of the storage tank 11.

Waste plastic stored inside the storage tank 11 in a slurry state can be discharged into the hopper unit 13 connected to the lower part of the storage tank 11.

The hopper unit 13 is a component for supplying the waste plastic in the molten slurry state to the thermal decomposition reactor 20, and is a first flow pipe 1301 that provides a space through which the waste plastic in the molten slurry state flows. And it may include a second flow pipe 1309 that covers the first flow pipe 1301 from the outside and provides a space through which the heating source flows.

The first flow pipe 1301 has a first rotary shaft 1303 that extends through the first flow pipe 1301, and a transfer screw coupled to the first rotary shaft 1303 and installed inside the first flow pipe 1301. It may include 1305 and a first rotation shaft drive motor 1307 that supplies rotational force to the first rotation shaft 1303.

Waste plastic in a molten slurry state flowing into the first flow pipe 1301 may be transported by the transfer screw 1305 rotated by the first rotation shaft drive motor 1307 and supplied to the pyrolysis reactor 20. . At this time, a heating source may flow inside the second flow pipe 1309 formed surrounding the outside of the first flow pipe 1301, and the heating source flows to raise the temperature inside the first flow pipe 1301 to a high temperature. By maintaining the waste plastic in a molten state, the primary decomposition reaction of vinyl chloride can occur.

Chlorine (Cl) gas can be generated through the primary decomposition reaction of vinyl chloride, and the chlorine (Cl) gas is hydrochloric acid along with moisture (H ₂ O) and light gas contained in waste plastic. It can be discharged outside the pyrolysis device in the form of (HCl).

High-temperature combustion flue gas may be used as the heating source, and although not shown in the drawing, the combustion flue gas may be used as a heating source and then reused through a cooling process, and the reused combustion flue gas (Flue Gas) can be discharged into the atmosphere after separating carbon dioxide (CO ₂ ) through a purification process.

In the hopper unit 13, leakage of pyrolysis gas may occur in the gap between the two outer surfaces of the first flow pipe 1301 in contact with the first rotation shaft 1303. To prevent this, a mechanical seal 40 may be installed on both outer surfaces of the first flow pipe 1301 penetrated by the first rotation shaft 1303, and at least a portion of the sealing member 40 is inert. An inert fluid supply unit 70 for supplying fluid is installed to double prevent leakage of the pyrolysis gas.

The inert fluid supplied through the inert fluid supply unit 70 may be carbon dioxide (CO ₂ ), but the present invention is not necessarily limited, and other known inert fluids may be adopted.

In one embodiment, the inert fluid supply unit 70 is an inert fluid supply unit 70 in the form of a tube in which one or more holes of a predetermined size are formed in the sealing member 40 and a space is formed in the holes through which the inert fluid can flow. The inert fluid can be supplied to the sealing member 40 by being connected, but the concept of the present invention is not necessarily limited thereto.

The pretreatment unit 10 according to the present invention is composed of a plurality of storage tanks 11 and a plurality of hopper units 13 that are driven alternately, and can be controlled so that the pretreatment process for waste plastic is continuously performed.

More specifically, the preprocessing unit 10 according to an embodiment of the present invention includes a first preprocessing unit 111, 131 consisting of a first storage tank 111 and a first hopper unit 131 connected thereto, and a second storage tank ( It may be a dual system including a second pretreatment unit (113, 133) consisting of a second hopper unit (113) and a second hopper unit (133) connected thereto, and the supply of cut and pulverized waste plastic is provided by the first storage tank (111). ) or can be controlled to be performed alternatively for the second storage tank 113.

As an example, while supplying molten waste plastic (Molten Plastic) pretreated in the first pretreatment units 111 and 131 to the pyrolysis reactor 20 to be described later, the second pretreatment units 113 and 133 perform pyrolysis. By discharging gas (Pyrolysis Gas) and/or supplying cut and pulverized waste plastic to the second storage tank 113, the pretreatment process can be performed continuously, thereby increasing the pyrolysis yield of waste plastic.

Referring to FIG. 3, the pyrolysis reactor 20 according to the present invention is a device for pyrolyzing pretreated waste plastic (Molten Plastic), and may be composed of a continuous stirred-tank reactor (CSTR). The concept of the present invention is not necessarily limited to this, and any other device for thermally decomposing waste plastic may be adopted.

The pyrolysis reactor 20 may include a pyrolysis tank 22, a heating source supply unit 24, and a stirring unit 26.

The pyrolysis tank 22 provides a space where pretreated waste plastic (Molten Plastic) is stored and pyrolysis is performed, and the heating source supply unit 24 covers the pyrolysis tank 22 from the outside, supplies a heating source, and stirs. The unit 26 is installed inside the pyrolysis tank 22 to stir the waste plastic.

More specifically, the pretreated waste plastic (Molten Plastic) supplied inside the pyrolysis tank 22 is pyrolyzed by the heating source supplied by the heating source supply unit 24 into waste plastic oil vapor (Waste Plastic Oil Vapor). may evaporate.

The waste plastic oil vapor can be discharged to the outside of the pyrolysis tank 22 through the waste plastic oil vapor discharge unit 80, and the waste plastic remaining without evaporation is pyrolyzed by the agitator 26. It circulates from the bottom of the tank 22 to the top and can be evaporated continuously.

The stirring unit 26 is coupled to the second rotating shaft 262, which extends through the upper surface of the pyrolysis tank 22, and is installed inside the pyrolysis tank 22 and agitates the waste plastic. It may include a second rotation shaft drive motor 266 that is coupled to the stirring member 264 and the second rotation shaft 262, is installed outside the pyrolysis tank 22, and supplies rotational force to the second rotation shaft 262, The waste plastic can be circulated inside the pyrolysis tank 22 by the agitator 26 to maximize the pyrolysis reaction.

The waste plastic oil vapor formed by thermal decomposition of waste plastic is subjected to a desalination process to remove chlorine (Cl) contained in the waste plastic oil vapor, and then undergo a condensation and purification process. It can be obtained in oil form.

The heating source supply unit 24 can control the temperature inside the pyrolysis tank 22 by flowing a high-temperature heating source along the outer surface of the pyrolysis tank 22.

High-temperature combustion flue gas may be used as the heating source, and although not shown in the drawing, the combustion flue gas may be used as a heating source and then reused through a cooling process, and the reused combustion flue gas (Flue Gas) can be discharged into the atmosphere after separating carbon dioxide (CO ₂ ) through a purification process.

A sealing member (mechanical seal, 40) may be installed on the outer surface of the pyrolysis tank 22 penetrated by the second rotation shaft 262 to prevent leakage of combustible gas present inside the pyrolysis tank 22, An inert fluid supply unit 70 for supplying an inert fluid may be installed on at least a portion of the sealing member 40.

The inert fluid supplied through the inert fluid supply unit 70 may be carbon dioxide (CO ₂ ), but the present invention is not necessarily limited, and other known inert fluids may be adopted.

In one embodiment, the inert fluid supply unit 70 is an inert fluid supply unit 70 in the form of a tube in which one or more holes of a predetermined size are formed in the sealing member 40 and a space is formed in the holes through which the inert fluid can flow. The inert fluid can be supplied to the sealing member 40 by being connected, but the concept of the present invention is not necessarily limited thereto.

Typically, waste plastic may contain metals, thermosetting resins, etc., and unevaporated residues such as metals, thermosetting resins, etc. are stored in the residue treatment unit 30 connected to the lower part of the thermal decomposition reactor 20. supplied.

The residue processing unit 30 may include a residue storage tank 31, a first rotary valve 33, a second rotary valve 35, and a residue discharge unit 37.

The residue storage tank 31 is connected to the pyrolysis tank 22 to provide a space for storing residue, and the first rotary valve 33 is connected to the pyrolysis tank 22 and the residue storage tank 31. It can be installed in the flow path between the channels to control the flow of residue.

In addition, the residue discharge unit 37 is connected to the residue storage tank 31 to discharge residue, and the second rotary valve 35 is connected to the residue storage tank 31 and discharges the residue. It is installed in the flow path between parts 37 to control the discharge of residue.

More specifically, the first rotary valve 33 may have a sealing member 40 installed on one side to prevent leakage of internal gas, and at least a portion of the sealing member 40 may be filled with an inert fluid for supplying the inert fluid. A supply unit 70 may be installed.

In addition, in one embodiment, the first rotary valve 33 is perpendicular to the flow path through which residue flows, and has a third rotation axis formed to extend through the first rotary valve 33 and the sealing member 40. 331) and a third rotation shaft driving motor 332 that is coupled to the third rotation shaft 331 and supplies rotational force to the third rotation shaft 331 from the outside of the first rotary valve 33.

The second rotary valve 35 may also be equipped with a sealing member 40 to prevent internal gas leakage, and an inert fluid supply unit 70 for supplying an inert fluid is installed on at least a portion of the sealing member 40. It can be.

The inert fluid supplied through the inert fluid supply unit 70 may be carbon dioxide (CO ₂ ), but the present invention is not necessarily limited and any known inert fluid may be adopted.

In one embodiment, the inert fluid supply unit 70 is an inert fluid supply unit 70 in the form of a tube in which one or more holes of a predetermined size are formed in the sealing member 40 and a space is formed in the holes through which the inert fluid can flow. By being connected, the inert fluid can be supplied to the sealing member 40.

In addition, in one embodiment, the second rotary valve 35 is perpendicular to the passage through which residue flows, and has a fourth rotation axis formed to extend through the second rotary valve 35 and the sealing member 40. 351) and a fourth rotation shaft 351 coupled to the fourth rotation shaft 351 may include a fourth rotation shaft drive motor 352 that supplies rotation force to the fourth rotation shaft 351 from outside the second rotary valve 35.

As described above, the first rotary valve 33 and the second rotary valve 35 can be controlled through the drive motors 332 and 352, but the concept of the present invention is not necessarily limited thereto, and the operator can manually control them. Any configuration for controlling the first rotary valve 33 and the second rotary valve 35 can be adopted.

In addition, carbon dioxide (CO ₂ ) supplied as an inert gas and inert fluid in the pyrolysis device for waste plastic according to the present invention is separated and recovered in the flue gas purification process, thereby reducing greenhouse gas atmospheric emissions. can do.

Although various embodiments of the present invention have been described in detail above, those skilled in the art will understand that various modifications can be made to the above-described embodiments without departing from the scope of the present invention. . Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined by the claims and equivalents of the claims as well as the claims described later.

10: preprocessing unit
11: storage tank
13: Hopper part
20: Pyrolysis reactor
22: Pyrolysis tank
24: Heating source supply unit
26: stirring unit
30: residue processing unit
31: residue storage tank
33: first rotary valve
35: second rotary valve
37: residue discharge unit
40: sealing member
50: Pyrolysis oil supply unit
60: Inert gas supply unit
70: Inert fluid supply part
80: Waste plastic vapor oil discharge unit

Claims (12)

A preprocessing unit for preprocessing cut and pulverized waste plastic; and
It includes a pyrolysis reactor for pyrolyzing the pretreated waste plastic,
The preprocessor,
a storage tank storing the cut and pulverized waste plastic in a molten slurry state;
a hopper unit for supplying the molten slurry waste plastic to the thermal decomposition reactor; and
It includes an inert gas supply unit connected to the storage tank to supply an inert gas,
The hopper part,
a first flow pipe providing a space through which the molten slurry waste plastic flows; and
It includes; a first rotation axis extending through the first flow pipe;
A mechanical seal is installed on the outer surface of the first flow pipe penetrated by the first rotation shaft to prevent leakage of internal gas, and an inert fluid is supplied to at least a portion of the sealing member. A supply department is established,
The pretreatment unit is composed of a plurality of storage tanks and a plurality of hopper units that are driven alternately, and is controlled so that the pretreatment process of the waste plastic is continuously performed. According to paragraph 1,
The preprocessing unit includes a first preprocessing unit consisting of a first storage tank and a first hopper unit connected thereto, and a second preprocessing unit consisting of a second storage tank and a second hopper unit connected thereto,
The pyrolysis device for waste plastic, characterized in that the supply of the cut and pulverized waste plastic is controlled to be performed alternatively to the first storage tank or the second storage tank. According to paragraph 1,
The preprocessor,
A pyrolysis oil supply unit connected to the storage tank to supply pyrolysis oil of high temperature and high boiling point. delete According to paragraph 1,
The hopper part,
A pyrolysis device for waste plastic, further comprising a second flow tube that covers the first flow tube on the outside and provides a space for the heating source to flow. According to clause 5,
The hopper unit includes a transfer screw that is coupled to the first rotation shaft and installed inside the first flow pipe and flows the waste plastic in the molten slurry state, and is coupled to the first rotation shaft to the outside of the first flow pipe. The thermal decomposition device for waste plastic further comprises a first rotation shaft drive motor installed in and supplying rotational force to the first rotation shaft. delete According to paragraph 1,
A pyrolysis device for waste plastic, characterized in that the pyrolysis reactor consists of a continuous stirred-tank reactor (CSTR). According to clause 8,
In the thermal decomposition reactor,
A pyrolysis tank that stores the pretreated waste plastic and provides a space where pyrolysis is performed;
a heating source supply unit that covers the pyrolysis tank from the outside and supplies a heating source; and
A pyrolysis device for waste plastic, comprising: a stirring unit installed inside the pyrolysis tank to agitate the waste plastic. According to clause 9,
The stirring unit includes a second rotation shaft extending through the upper surface of the pyrolysis tank, a stirring member coupled to the second rotation shaft and installed inside the pyrolysis tank and stirring the waste plastic, and a second rotation shaft. It is installed outside the pyrolysis tank and includes a second rotation shaft drive motor that supplies rotational force to the second rotation shaft,
A mechanical seal is installed on the outer surface of the pyrolysis tank penetrated by the second rotating shaft to prevent leakage of internal gas, and at least a portion of the sealing member has an inert fluid supply unit for supplying an inert fluid. A thermal decomposition device for waste plastic, characterized in that it is installed. According to clause 9,
a residue storage tank connected to the pyrolysis tank to provide a space for storing residue; and
It further includes a first rotary valve installed in the flow path between the pyrolysis tank and the residue storage tank to control the flow of the residue,
The first rotary valve is installed with a mechanical seal to prevent leakage of internal gas, and an inert fluid supply part for supplying an inert fluid is installed on at least a portion of the sealing member. Device. According to clause 11,
a residue discharge unit connected to the residue storage tank to discharge residue; and
It further includes a second rotary valve installed in the passage between the residue storage tank and the residue discharge unit to control discharge of the residue,
The second rotary valve is installed with a mechanical seal to prevent internal gas leakage, and an inert fluid supply part for supplying an inert fluid is installed on at least a portion of the sealing member. Device.