KR102563035B1 - System for recycling waste plastic - Google Patents

Abstract

The present invention relates to a waste plastic recycling system. A waste plastic recycling system according to an embodiment of the present invention includes a pyrolysis reaction unit in which pyrolysis gas is generated by pyrolyzing waste plastic; It is connected to the pyrolysis reaction unit, and is preheated by receiving at least one of waste heat of the pyrolysis reaction unit and excess pyrolysis gas of the pyrolysis reaction unit, and when the preheating is completed, pyrolysis gas is supplied from the pyrolysis reaction unit to remove wax components included in the pyrolysis gas a catalyst unit for generating refined pyrolysis gas; A condensing unit connected to the catalyst unit and condensing the purified pyrolysis gas supplied from the catalyst unit to generate condensed pyrolysis gas; a cooling unit connected to the condensing unit and receiving and cooling the condensed pyrolysis gas from the condensing unit to separate the pyrolysis oil from the condensed pyrolysis gas; and a purification unit connected to the cooling unit and receiving and purifying the pyrolysis oil from the cooling unit to separate the refined pyrolysis oil from the pyrolysis oil.

Description

Waste plastic recycling system {SYSTEM FOR RECYCLING WASTE PLASTIC}

The present invention relates to a waste plastic recycling system.

Plastic is a type of petroleum compound that uses petroleum as its main raw material. As it is made in the form of a polymer, it is difficult to decompose and can be used for a long time. It is widely used throughout.

On the other hand, as the amount of plastic is rapidly increasing, the amount of waste plastic discarded after use is also rapidly increasing. Existing waste plastic treatment relied on incineration or landfill, but it has become a problem due to secondary environmental pollution such as a lack of landfill and generation of harmful gases due to incineration. Due to such environmental problems, increased waste disposal costs, limitations of landfills, and the like, interest in a waste plastic pyrolysis process technology that pyrolyzes and treats waste plastic is increasing.

In the pyrolysis process technology of waste plastics, pyrolysis oil is produced by cooling gas among pyrolysis products of waste plastics. The pyrolysis oil produced in this way can be used as an alternative fuel to diesel, and can be stored and moved, so it has high utilization value and is useful in solving environmental pollution problems. At this time, the pyrolysis process of waste plastics can be divided into a batch process mainly used for small-scale plants of 2,000 tons/year or less and a continuous process mainly used for large-scale plants of 5,000 tons/year or more.

First, in the batch process, waste plastic is put into a batch reactor, and when the batch reactor is heated, the waste plastic in the batch reactor is thermally decomposed. However, when the thermal decomposition of the waste plastic is completed, since the thermal decomposition reaction residue remains inside the batch reactor, the waste plastic cannot be introduced into the batch reactor any longer. Therefore, in the batch process, after the pyrolysis reaction of waste plastic is completed, the batch reactor is cooled to remove the pyrolysis reaction residue remaining in the batch reactor, and then the waste plastic is introduced into the batch reactor again. Therefore, the batch process has disadvantages of high operating cost, low thermal efficiency, and low productivity. In addition, since the pyrolysis oil produced through the batch process includes a wax component, the pyrolysis oil is easily coagulated, and as a result, the quality of the finally produced refined pyrolysis oil is degraded.

On the other hand, in order to compensate for the disadvantages of the batch process, a continuous process has been proposed in which waste plastic is input, pyrolysis reaction of waste plastic, discharge and treatment of pyrolysis reaction residues, purification of pyrolysis oil, etc. are continuously performed. Since most of the processes are automated, such a continuous process has the advantages of low operating cost, high thermal efficiency, and improved productivity, but has the disadvantage of requiring a large initial investment.

Therefore, there is a need for a waste plastic recycling system capable of compensating for the disadvantages of the batch process, achieving performance similar to that of the continuous process, and obtaining refined pyrolysis oil of excellent quality from the waste plastic.

Embodiments of the present invention have been made to solve the above-mentioned problems in the prior art, and can implement performance of similar efficiency to that of the continuous process while compensating for the disadvantages of the batch process, and can obtain refined pyrolysis oil of excellent quality from waste plastics. We want to provide a waste plastic recycling system that can

According to one aspect of the present invention, a thermal decomposition reaction unit in which thermal decomposition gas is generated by thermal decomposition of waste plastic; It is connected to the pyrolysis reaction unit, is preheated by receiving at least one of waste heat of the pyrolysis reaction unit and surplus pyrolysis gas of the pyrolysis reaction unit, and when the preheating is completed, receives the pyrolysis gas from the pyrolysis reaction unit to supply the pyrolysis gas A catalyst unit for generating refined pyrolysis gas by removing the included wax component; a condensing unit connected to the catalyst unit and condensing the purified pyrolysis gas supplied from the catalyst unit to generate condensed pyrolysis gas; a cooling unit connected to the condensing unit and configured to receive and cool the condensed pyrolysis gas from the condensing unit to separate pyrolysis oil from the condensed pyrolysis gas; and a purification unit connected to the cooling unit and receiving and purifying the pyrolysis oil from the cooling unit to separate purified pyrolysis oil from the pyrolysis oil.

In addition, a plurality of thermal decomposition reaction units are provided, the plurality of thermal decomposition reaction units are connected in parallel to each other, and excess pyrolysis gas generated from at least a part of the plurality of thermal decomposition reaction units connected in parallel with each other is used to treat the rest of the plurality of thermal decomposition reaction units and the catalyst. It may be supplied to at least one of the parts.

In addition, the pyrolysis reaction unit includes a pyrolysis reactor having an inlet on one side, an outlet on the other side, and a space in which the pyrolysis of the waste plastic can be performed; at least one heating device connected to the pyrolysis reactor and heating the pyrolysis reactor; a connecting pipe coupled to the outlet of the pyrolysis reactor so that at least a portion of an end thereof is disposed inside the pyrolysis reactor; and a sealing member coupled to the outside of the connection pipe and provided inside a fluid filling part filled with a fluid to prevent leakage of the pyrolysis gas inside the pyrolysis reactor to the outside.

In addition, a first processing unit connected to the condensing unit and the cooling unit, receiving and processing at least one of wastewater from the condensing unit and wastewater from the cooling unit; and a second processing unit that is connected to the cooling unit and receives and processes the cooling pyrolysis gas remaining after the pyrolysis oil is separated from the condensed pyrolysis gas.

In addition, a control unit for controlling at least one of the plurality of thermal decomposition reaction units, the catalyst unit, the condensation unit, the cooling unit, the purification unit, the first processing unit, and the second processing unit may be further included.

In addition, the control unit may control the catalyst unit to discharge catalytic reaction residues of the catalyst unit when the separation of the refined pyrolysis oil from the pyrolysis oil in the purifier unit is completed.

In addition, the control unit controls the thermal decomposition reaction unit to discharge thermal decomposition reaction residues from the thermal decomposition reaction unit when thermal decomposition of the waste plastic is completed in the thermal decomposition reaction unit, and the thermal decomposition reaction residues discharged from the thermal decomposition reaction unit are At least one of the waste heat of the catalyst unit and the waste heat of the purification unit may be treated.

In addition, the control unit controls the purification unit so that the purification reaction residue is discharged from the purification unit when the separation of the refined pyrolysis oil is completed in the purification unit, and the purification reaction residue discharged from the purification unit is mixed with the pyrolysis reaction residue. Mixing can be done.

In addition, the control unit may control the catalyst unit to discharge catalytic reaction residues of the catalyst unit when the separation of the refined pyrolysis oil from the pyrolysis oil in the purifier unit is completed.

The thermal decomposition reaction unit may further include a temperature sensor installed in the thermal decomposition reactor and measuring a temperature of the thermal decomposition reactor, and the controller may control the heating device and the heating device based on the measured value of the temperature sensor. At least one of the second processing units may be controlled.

The control unit may control the second processing unit to supply at least a portion of the pyrolysis gas processed by the second processing unit to at least one of the first processing unit and the heating device.

In addition, a hydrogen generating unit connected to the refining unit to receive the purified pyrolysis oil separated from the refining unit and generating hydrogen using the refined pyrolysis oil may be further included.

In addition, the controller may control at least a portion of unreacted gas generated in the process of generating hydrogen from the refined pyrolysis oil in the hydrogen generating unit to be supplied to the pyrolysis reaction unit.

According to the embodiments of the present invention, it is possible to achieve performance similar to that of the continuous process while compensating for the disadvantages of the batch process, and to obtain refined pyrolysis oil of excellent quality from waste plastics.

1 is a block diagram showing a waste plastic recycling system according to an embodiment of the present invention.
FIG. 2 is a process flow diagram of the waste plastic recycling system of FIG. 1 .
FIG. 3 is a block diagram of the waste plastic recycling system of FIG. 1 .
FIG. 4 is a view showing a thermal decomposition reaction unit of the waste plastic recycling system of FIG. 1 .
5 is a block diagram showing a waste plastic recycling system according to another embodiment of the present invention.
6 is a process flow diagram of the waste plastic recycling system of FIG. 5 .

Hereinafter, specific embodiments for implementing the spirit of the present invention will be described in detail with reference to the drawings.

In addition, in the description of the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description will be omitted.

In addition, it should be understood that when a component is referred to as being 'coupled' or 'connected' to another component, it may be directly coupled or connected to the other component, but other components may exist in the middle.

Terms used in this specification are only used to describe specific embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise.

In addition, in this specification, expressions such as one side, the other side, the upper side, the lower side, etc. are described based on the drawings, and it is made clear in advance that they may be differently expressed when the direction of the object is changed. For the same reason, some components in the accompanying drawings are exaggerated, omitted, or schematically illustrated, and the size of each component does not entirely reflect the actual size.

In addition, terms including ordinal numbers, such as first and second, may be used to describe various components, but the components are not limited by these terms. These terms are only used to distinguish one component from another.

As used herein, the meaning of 'comprising' specifies specific characteristics, regions, integers, steps, operations, elements and/or components, and other specific characteristics, regions, integers, steps, operations, elements, components and/or groups. does not exclude the presence or addition of

Hereinafter, a detailed configuration of a waste plastic recycling system according to an embodiment of the present invention will be described with reference to the drawings.

1 to 4, the waste plastic recycling system 1 according to an embodiment of the present invention includes a thermal decomposition reaction unit 10, a catalyst unit 20, a condensation unit 30, a cooling unit 40, It may include a purification unit 50, a first processing unit 60, a second processing unit 70 and a control unit 80.

The thermal decomposition reaction unit 10 may receive and thermally decompose waste plastic. To this end, the pyrolysis reactor 10 may include a pyrolysis reactor 11, a heating device 12, a connection pipe 13, a sealing member 14, and a temperature sensor 15.

The pyrolysis reactor 11 is a part in which the pyrolysis reaction of waste plastic is performed, and may have a space in which the pyrolysis reaction of waste plastic can be performed. The pyrolysis reactor 11 may be indirectly heated through the heating device 12, and the temperature of the pyrolysis reactor 11 raised by the heating device 12 is the waste plastic inside the pyrolysis reactor 11. It can be maintained by pyrolysis gas generated during pyrolysis. An inlet (not shown) may be provided on one side of the pyrolysis reactor 11, and an outlet 111 may be provided on the other side of the pyrolysis reactor 11.

At this time, the pyrolysis reactor 11 may be equipped with, for example, a rotary kiln-type reactor. Accordingly, the pyrolysis reactor 11 may be rotatably provided, and a spiral blade (not shown) may be installed on an inner circumferential surface of the pyrolysis reactor 11 . As a result, the waste plastic introduced through the inlet may be pyrolyzed while moving toward the outlet 111 by the spiral blade.

Meanwhile, in the process of pyrolyzing waste plastic in the pyrolysis reactor 11, pyrolysis gas, for example, oil vapor may be generated. The pyrolysis gas may be supplied to the catalyst unit 20 , and wax components included in the pyrolysis gas may be removed through the catalyst unit 20 . I will tell you more about this later.

The heating device 12 may indirectly heat the pyrolysis reactor 11 so that the pyrolysis reaction of waste plastic can be performed in the pyrolysis reactor 11 . To this end, the heating device 12 may be connected to the pyrolysis reactor 11 and may be provided with at least one. At this time, the heating device 12 may be provided as a burner for heating the pyrolysis reactor 11, for example.

The heating device 12 may be provided to generate combustion gas by receiving LPG as fuel. In addition, the heating device 12 may be provided to generate combustion gas by receiving the pyrolysis gas processed in the second processing unit 70 as fuel. I will tell you more about this later.

The connection pipe 13 is a pipe through which a pyrolysis product generated through a pyrolysis reaction of waste plastic passes inside the pyrolysis reactor 11, and may be coupled to the outlet 111 of the pyrolysis reactor 11. At this time, the pyrolysis reactor 11 may be relatively rotated with the connecting pipe 13 as an axis.

The sealing member 14 may prevent leakage of pyrolysis gas among pyrolysis products inside the pyrolysis reactor 11 or external air from flowing into the pyrolysis reactor 11 . To this end, the sealing member 14 may be coupled to the outside of the connecting pipe 13 . At this time, a fluid filling part 141 filled with fluid may be provided inside the sealing member 14 . For example, the fluid filled in the fluid filling unit 141 may be an inert gas such as nitrogen or hydraulic oil.

The temperature sensor 15 may measure the temperature of the thermal decomposition reactor 11 and transmit the measured temperature value of the thermal decomposition reactor 11 to the control unit 80 . To this end, the temperature sensor 15 may be connected to the pyrolysis reactor 11 . The measured value of the temperature sensor 15 transmitted to the controller 80 may be used by the controller 80 to control at least one of the heating device 12 and the second processing unit 70 . For example, the controller 80 compares the measured value of the temperature sensor 15 with a preset value to control the heating device 12 so that fuel such as LPG is supplied to the heating device 12, or the second processing unit ( The second processing unit 70 may be controlled so that the processing pyrolysis gas of 70 is supplied to the heating device 12 .

Meanwhile, a plurality of thermal decomposition reaction units 10 may be provided. As shown in Figure 3, a plurality of thermal decomposition reaction units (10a, 10b, 10c) may be connected in parallel with each other. As such, when the plurality of thermal decomposition reaction units 10a, 10b, and 10c are connected in parallel, waste heat or excess pyrolysis gas generated in at least one of the plurality of thermal decomposition reaction units 10a, 10b, and 10c is converted into a plurality of thermal decomposition reaction units 10a , 10b, 10c) can be used to heat the rest. Alternatively, waste heat or surplus pyrolysis gas generated in at least one of the plurality of thermal decomposition reaction units 10a, 10b, and 10c may be supplied to the catalyst unit 20 and used to preheat the catalyst unit 20. In addition, waste heat or excess pyrolysis gas generated in at least one of the plurality of thermal decomposition reaction units 10a, 10b, and 10c is supplied to the purification unit 50 and used to heat or preheat the purification unit 50. I will tell you more about this later.

The catalyst unit 20 receives a thermal decomposition gas, for example, oil vapor, from the thermal decomposition reaction unit 10, and may remove a wax component included in the thermal decomposition gas supplied from the thermal decomposition reaction unit 10 using the catalyst. In this case, since the removal of the wax component from the pyrolysis gas means that the pyrolysis gas is purified, 'pyrolysis gas from which the wax component is removed' may be referred to as 'purified pyrolysis gas'. For example, the catalyst is a honeycomb or cylindrical shape with zeolite as a support, and the components that act as catalysts include about 1% to about 10% of copper (Cu), 1 to 20% of iron (Fe), and about 1% to about 10% of iron (Fe). Contains 10% of zinc (Zn) and may include activated clay as a porous material to increase the specific surface area

On the other hand, as shown by the one-dot chain arrow in FIG. 2, the catalyst unit 20 is connected to the thermal decomposition reaction unit 10 to generate at least one of waste heat of the thermal decomposition reaction unit 10 and excess pyrolysis gas of the thermal decomposition reaction unit 10. One can be supplied. Here, the waste heat of the pyrolysis reactor 10 means the heat of the combustion gas of the heating device 12 conducted to the pyrolysis reactor 11, and the surplus pyrolysis gas of the pyrolysis reactor 10 is the pyrolysis reactor 11 ) means the remaining pyrolysis gas except for the pyrolysis gas used to maintain the temperature.

At this time, when at least one of the waste heat of the thermal decomposition reaction unit 10 and the surplus thermal decomposition gas of the thermal decomposition reaction unit 10 is supplied to the catalyst unit 20, the catalyst unit 20 generates waste heat and thermal decomposition of the thermal decomposition reaction unit 10 It may be preheated by at least one of the excess pyrolysis gas of the reaction unit 10 . For example, the catalyst unit 20 may be preheated to about 250° C. to about 350° C. through at least one of waste heat of the thermal decomposition reaction unit 10 and excess pyrolysis gas of the thermal decomposition reaction unit 10 .

Meanwhile, the catalyst unit 20 generates at least one of the waste heat of the thermal decomposition reaction unit 10 and the excess pyrolysis gas of the thermal decomposition reaction unit 10 before the waste plastic is thermally decomposed in the thermal decomposition reaction unit 10 and the pyrolysis gas is generated. can be warmed up by In other words, before the thermal decomposition gas of the thermal decomposition reaction unit 10 is supplied to the catalyst unit 20, the catalyst unit 20 may be preheated. Accordingly, since the preheating of the catalyst unit 20 is completed first before the thermal decomposition reaction of the thermal decomposition reaction unit 10 is completed, the catalyst unit 20 is included in the pyrolysis gas even during the initial operation of the waste plastic recycling system 1. As the wax component can be removed, the quality of the finally produced refined pyrolysis oil can be improved.

In this way, when the wax component included in the pyrolysis gas is removed from the catalyst unit 20 preheated to a predetermined temperature, catalyst reaction residues remain in the catalyst unit 20 . These catalytic reaction residues may be discharged when the separation of refined pyrolysis oil from pyrolysis oil in the refinery unit 50 is completed. In addition, as described above, since the preheating of the catalyst unit 20 is completed first before the thermal decomposition reaction of the thermal decomposition reaction unit 10 is completed, even during the initial operation of the waste plastic recycling system 1, the catalyst unit 20 The catalytic reaction residue of may not be solidified in the catalyst part 20 . Accordingly, the problem of deterioration in stability due to the increase in pressure of the catalytic unit 20 due to the solidification of the catalytic reaction residues can be prevented in advance.

The condensing unit 30 may receive the purified pyrolysis gas from the catalyst unit 20 and condense the supplied purified pyrolysis gas to remove moisture contained in the purified pyrolysis gas. Since the refined pyrolysis gas from which moisture is removed in the condenser 30 is generated by condensing the purified pyrolysis gas, 'refined pyrolysis gas from which moisture is removed' may be referred to as 'condensed pyrolysis gas'.

At this time, the condenser 30 may condense moisture contained in the refined pyrolysis gas using cooling water. The condensed pyrolysis gas from which moisture is removed from the refined pyrolysis gas may be supplied to the cooling unit 40, and the moisture removed from the refined pyrolysis gas, that is, condensate water, may be regarded as wastewater and supplied to the first treatment unit 60. .

On the other hand, since the condensing unit 30 removes moisture from the refined pyrolysis gas to generate the condensed pyrolysis gas, when the cooling unit 40 separates the pyrolysis oil from the condensed pyrolysis gas, the separated pyrolysis oil contains a large amount of moisture. can be prevented

The cooling unit 40 may separate the pyrolysis oil from the condensed pyrolysis gas by receiving and cooling the condensed pyrolysis gas from the condensing unit 30 . At this time, the cooling unit 40 may separate the pyrolysis oil from the condensed pyrolysis gas by gas-liquid separation of the condensed pyrolysis gas using cooling water. Here, the condensed pyrolysis gas remaining after the pyrolysis oil is separated from the condensed pyrolysis gas is obtained by cooling the condensed pyrolysis gas, so it may be referred to as 'cooled pyrolysis gas'.

On the other hand, the cooling water obtained by gas-liquid separation of the condensed pyrolysis gas may be regarded as wastewater and supplied to the first treatment unit 60, and the pyrolysis oil separated from the condensed pyrolysis gas may be supplied to the purifier 50, and the cooling pyrolysis gas may be supplied to the second processing unit 70.

The refiner 50 receives the pyrolysis oil from the cooling unit 40 and separates the purified pyrolysis oil from the pyrolysis oil by purifying the pyrolysis oil under reduced pressure. To this end, the purification unit 50 may be connected to the cooling unit 40 . The refiner 50 may separate refined pyrolysis oil from pyrolysis oil by exchanging heat between pyrolysis oil supplied from the cooling unit 40 and heat supplied from a boiler (not shown) to increase the temperature of the pyrolysis oil. In this case, pyrolysis oils having different boiling points, such as naphtha, can be obtained from pyrolysis oil by controlling the temperature of the boiler.

The purification unit 50 may be connected to the thermal decomposition reaction unit 10 to receive at least one of waste heat from the thermal decomposition reaction unit 10 and excess pyrolysis gas from the thermal decomposition reaction unit 10 . When at least one of waste heat from the thermal decomposition reaction unit 10 and excess pyrolysis gas from the thermal decomposition reaction unit 10 is supplied to the purification unit 50 , the purification unit 50 may be preheated or heated.

At this time, when the separation of the refined pyrolysis oil is completed in the purification unit 50, refining reaction residues may remain in the purification unit 50. These refining reaction residues contain a high concentration of wax components. For example, the purification reaction residue may have a calorific value of about 10,000 kcal/kg to about 12,000 kcal/kg.

Meanwhile, the purification reaction residue of the purification unit 50 may be mixed with the thermal decomposition reaction residue of the thermal decomposition reaction unit 10 . When the refining reaction residue of the refining unit 50 and the thermal decomposition reaction residue of the thermal decomposition reaction unit 10 are mixed in this way, the wax component of the refining reaction residue of the refining unit 50 can serve as a binder for solid fuel, It can serve to increase the calorific value of the fuel, and the thermal decomposition reaction residue of the thermal decomposition reaction unit 10 can be used as a support for maintaining the shape of the solid fuel.

The first processing unit 60 may receive and treat at least one of wastewater from the condensing unit 30 and wastewater from the cooling unit 40 . To this end, the first processing unit 60 may be connected to the condensing unit 30 and the cooling unit 40 . Here, the wastewater of the condensing unit 30 refers to condensed water removed from the refined pyrolysis gas supplied to the condensing unit 30, and the wastewater of the cooling unit 40 cools the condensed pyrolysis gas supplied to the cooling unit 40. means coolant.

At this time, the wastewater of the condensing unit 30 and the wastewater of the cooling unit 40 supplied to the first processing unit 60 are incinerated through the process pyrolysis gas treated in the second processing unit 70 and evaporated. The evaporated gas generated in this way is purified by passing through a separate scrubber (not shown) and then discharged into the atmosphere.

The second processing unit 70 may receive and process the cooled pyrolysis gas separated from the cooling unit 40 . To this end, the second processing unit 70 may be connected to the cooling unit 40 and the first processing unit 60 .

In this case, the second processing unit 70 may purify and process the cooled pyrolysis gas supplied from the cooling unit 40 to generate a processed pyrolysis gas. The generated pyrolysis gas is supplied to the first treatment unit 60 and used for incineration of wastewater from the condensing unit 30 and wastewater from the cooling unit 40 . In addition, the processed pyrolysis gas generated in the second processing unit 70 may be supplied as fuel of the heating device 12 and used to heat the pyrolysis reactor 11 . In addition, the treated pyrolysis gas generated in the second processing unit 70 may be incinerated and then discharged into the atmosphere, or may be used to incinerate pyrolysis reaction residues discharged from the pyrolysis reaction unit 10 .

The control unit 80 is among the thermal decomposition reaction unit 10, the catalyst unit 20, the condensation unit 30, the cooling unit 40, the purification unit 50, the first processing unit 60 and the second processing unit 70. You can control at least one. To this end, the control unit 80 may be formed of, for example, a small built-in computer, and may include a program, a memory, and a data processing unit including a CPU. These programs are installed in the pyrolysis reaction unit 10, the catalyst unit 20, the condensation unit 30, the cooling unit 40, the purification unit 50, the first processing unit 60 and the second processing unit 70. The thermal decomposition reaction unit 10, the catalyst unit 20, the condensation unit 30, the cooling unit 40, the purification unit 50, the first processing unit 60 and An algorithm for controlling at least one of the second processing units 70 may be included. In addition, these programs may be stored in a memory such as a computer storage medium such as a flexible disk, a compact disk, a hard disk, or a magneto-optical disk (MO) and installed in the control unit 80.

In the waste plastic recycling system 1 having the configuration described above, a plurality of thermal decomposition reaction units 10 are connected in parallel, and waste heat from the plurality of thermal decomposition reaction units 10 can be utilized for preheating of the catalyst unit 20. there is. In addition, the excess thermal decomposition gas of any one of the thermal decomposition reaction units 10 of the plurality of thermal decomposition reaction units 10 connected in parallel heats the remaining thermal decomposition reaction units 10 among the plurality of thermal decomposition reaction units 10, or the catalyst unit ( 20) can be used for preheating. Therefore, compared to the continuous process, the waste plastic recycling system 1 requires less operating cost, higher thermal efficiency, and improved productivity, so it can compensate for the disadvantages of the batch process and realize performance with efficiency similar to that of the continuous process. there is

In addition, since the catalyst unit 20 is preheated by at least one of waste heat from the plurality of thermal decomposition reaction units 10 and excess pyrolysis gas of the plurality of thermal decomposition reaction units 10, the wax component removal efficiency of the catalyst unit 20 is improved. There is an effect that it is possible to obtain refined pyrolysis oil of excellent quality from waste plastic.

In addition, as the plurality of thermal decomposition reaction units 10 connected in parallel share the latter process, the initial investment cost is low, and the operation and maintenance are easy because the latter process is integrated.

In addition, as the thermal decomposition reaction residues of the pyrolysis reaction unit 10 and the purification reaction residues of the purification unit 50 are mixed and used as solid fuel, the cost of treating the residues is reduced, thereby ensuring economic feasibility.

Hereinafter, a waste plastic recycling system 1' according to another embodiment of the present invention will be described with reference to FIGS. 5 and 6 .

5 and 6, the waste plastic recycling system 1' according to another embodiment of the present invention includes a thermal decomposition reaction unit 10, a catalyst unit 20, a condensation unit 30, and a cooling unit 40. , It may include a purification unit 50, a first processing unit 60, a second processing unit 70, a control unit 80 and a hydrogen generating unit 90. However, since the waste plastic recycling system 1′ shown in FIGS. 5 and 6 is substantially the same as the waste plastic recycling system 1 shown in FIGS. 1 to 4 except for the hydrogen generator 90, Hereinafter, the hydrogen generator 90 corresponding to the difference will be mainly described, and the description and reference numerals of the above-described embodiment will be used for the same parts.

The hydrogen generator 90 may receive a supply of refined pyrolysis oil, for example, naphtha, from the refiner 50, and generate hydrogen using the supplied naphtha. To this end, the hydrogen generating unit 90 may be connected to the purifying unit 50 .

At this time, the hydrogen generator 90 may separate high-purity hydrogen from naphtha through a naphtha refining process, a dry carbon dioxide capture process, a water gas transfer process, and a PSA process. At this time, the unreacted gas of the PSA process may be supplied to the heating device 12 and used to heat the pyrolysis reaction unit 10 or may be used to incinerate pyrolysis reaction residues discharged from the pyrolysis reaction unit 10.

Since the waste plastic recycling system 1' having the configuration described above can separate naphtha from waste plastic and obtain high-purity hydrogen from the separated naphtha, a virtuous cycle economic structure can be established, and the hydrogen economy can be revitalized. There is an effect that you can contribute.

Although the embodiments of the present invention have been described as specific embodiments, this is merely an example, and the present invention is not limited thereto, and should be construed as having the widest scope according to the basic ideas disclosed herein. A person skilled in the art may implement a pattern of a shape not indicated by combining/substituting the disclosed embodiments, but this also does not deviate from the scope of the present invention. In addition, those skilled in the art can easily change or modify the disclosed embodiments based on this specification, and it is clear that such changes or modifications also fall within the scope of the present invention.

1, 1': waste plastic recycling system 10: pyrolysis reaction unit
11: pyrolysis reactor 12: heating device
13: connector 14: sealing member
15: temperature sensor 20: catalyst unit
30: condensation unit 40: cooling unit
50: purification unit 60: first processing unit
70: second processing unit 80: control unit
90: hydrogen generating unit 111: outlet
141: fluid filling part

Claims (12)

A thermal decomposition reaction unit for generating thermal decomposition gas by thermal decomposition of waste plastic;
It is connected to the pyrolysis reaction unit, is preheated by receiving at least one of waste heat of the pyrolysis reaction unit and surplus pyrolysis gas of the pyrolysis reaction unit, and when the preheating is completed, receives the pyrolysis gas from the pyrolysis reaction unit to supply the pyrolysis gas A catalyst unit for generating refined pyrolysis gas by removing the included wax component;
a condensing unit connected to the catalyst unit and condensing the purified pyrolysis gas supplied from the catalyst unit to generate condensed pyrolysis gas;
a cooling unit connected to the condensing unit and configured to receive and cool the condensed pyrolysis gas from the condensing unit to separate pyrolysis oil from the condensed pyrolysis gas;
Is connected to the pyrolysis reaction unit to receive at least one of waste heat of the pyrolysis reaction unit and surplus pyrolysis gas of the pyrolysis reaction unit to be preheated or heated, connected to the cooling unit to receive the pyrolysis oil from the cooling unit, and the pyrolysis A refinery unit for purifying oil and separating refined pyrolysis oil from the pyrolysis oil; and
A hydrogen generating unit connected to the refining unit to receive the refined pyrolysis oil from the refining unit and generating hydrogen using the refined pyrolysis oil;
A plurality of the thermal decomposition reaction units are provided, and a plurality of the thermal decomposition reaction units are connected in parallel to each other,
At least one of waste heat and excess pyrolysis gas generated from at least some of the plurality of pyrolysis reaction units connected in parallel to each other is supplied to the catalyst unit before the pyrolysis gas to preheat the catalyst unit;
The thermal decomposition reaction residue discharged from the thermal decomposition reaction unit is treated by at least one of waste heat from the catalyst unit and waste heat from the purification unit,
The pyrolysis reaction residue treated by at least one of the waste heat of the catalyst part and the waste heat of the purification part is mixed with the purification reaction residue discharged from the purification part and used as a solid fuel.
Waste plastic recycling system. According to claim 1,
At least one of the waste heat and excess pyrolysis gas generated from at least some of the plurality of pyrolysis reaction units connected in parallel to each other is supplied to at least one of the remaining pyrolysis reaction units and the purification unit,
Waste plastic recycling system. According to claim 2,
The thermal decomposition reaction unit,
a pyrolysis reactor having an inlet on one side, an outlet on the other side, and a space in which the waste plastic can be pyrolyzed;
at least one heating device connected to the pyrolysis reactor and heating the pyrolysis reactor;
a connection pipe coupled to the outlet of the pyrolysis reactor; and
A sealing member coupled to the outside of the connection pipe and provided inside a fluid filling portion filled with fluid to prevent leakage of the pyrolysis gas inside the pyrolysis reactor to the outside,
Waste plastic recycling system. According to claim 3,
a first processing unit connected to the condensing unit and the cooling unit, receiving and processing at least one of wastewater from the condensing unit and wastewater from the cooling unit; and
A second processing unit connected to the cooling unit and receiving and processing the cooling pyrolysis gas remaining after the pyrolysis oil is separated from the condensed pyrolysis gas,
Waste plastic recycling system. According to claim 4,
Further comprising a control unit for controlling at least one of the plurality of thermal decomposition reaction units, the catalyst unit, the condensation unit, the cooling unit, the purification unit, the first processing unit and the second processing unit,
Waste plastic recycling system. According to claim 5,
The control unit,
When the thermal decomposition of the waste plastic is completed in the thermal decomposition reaction unit, controlling the thermal decomposition reaction unit to discharge the thermal decomposition reaction residue from the thermal decomposition reaction unit.
Waste plastic recycling system. According to claim 6,
The control unit,
When the separation of the refined pyrolysis oil in the refining unit is completed, controlling the refining unit so that the refining reaction residue is discharged from the refining unit,
Waste plastic recycling system. According to claim 5,
The control unit,
When the separation of the refined pyrolysis oil from the pyrolysis oil in the purifier is completed, controlling the catalytic unit so that the catalytic reaction residue of the catalytic unit is discharged,
Waste plastic recycling system. According to claim 5,
The thermal decomposition reaction unit,
Further comprising a temperature sensor installed in the pyrolysis reactor and measuring a temperature of the pyrolysis reactor,
The control unit,
Controlling at least one of the heating device and the second processing unit based on the measured value of the temperature sensor,
Waste plastic recycling system. According to claim 5,
The control unit,
Controlling the second processing unit so that at least a portion of the processed pyrolysis gas processed in the second processing unit is supplied to at least one of the first processing unit and the heating device.
Waste plastic recycling system. delete According to claim 5,
The control unit,
Controlling at least a portion of the unreacted gas generated in the process of generating hydrogen from the refined pyrolysis oil in the hydrogen generating unit to be supplied to the pyrolysis reaction unit,
Waste plastic recycling system.

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