KR20240012185A - Apparatus for collecting Pyrolysis wax using gas jet and waste plastic pyrolysis system including the pparatus - Google Patents

Abstract

The present invention relates to a gas jet spray pyrolysis wax collection device, a waste plastic pyrolysis system and method having the collection device, and more specifically, to a device for collecting wax in a process for pyrolyzing waste streams, which is configured in the form of a tube. body; A pyrolysis gas inlet provided on one side of the body into which pyrolysis gas generated through a pyrolysis furnace flows; A high-speed jet gas injection tube located inside the body in the longitudinal direction to spray high-speed jet gas toward the inner wall of the body to condense wax; a wax discharge unit connected to the other side of the body and discharging condensed wax; and a pyrolysis gas discharge path through which the pyrolysis gas from which the wax has been removed is discharged. It relates to a gas jet spray pyrolysis wax collection device, including a.

Description

Gas jet spray pyrolysis wax collection device, waste plastic pyrolysis system and method having the collection device {Apparatus for collecting Pyrolysis wax using gas jet and waste plastic pyrolysis system including the pparatus}

The present invention relates to a gas jet spray pyrolysis wax collection device, and a waste plastic pyrolysis system and method having the same collection device.

In Korea, approximately 4 million tons of waste plastic is generated every year, but the recycling rate is low at 20-30%, and a large amount is disposed of through landfill or incineration. However, landfilling of waste plastic may result in leaching of harmful components, and the volume is large compared to unit weight, causing problems with storage, transportation, and landfill. In addition, treatment by incineration can use some of the heat energy generated during incineration, but it causes a lot of economic loss and causes environmental destruction by emitting toxic gases, so social interest in methods of recycling waste plastic is growing. It's getting higher.

Waste plastics are mainly processed using energy recovery methods to recover combustion heat, and for this purpose, they are molded into solid fuel, Refuse Plastic Fuel (RPF), and then injected. Another waste plastic disposal method is recycling. The recycling methods for waste plastic are largely mechanical recycling, which involves melting waste plastic at around 300°C to create recycled particles in the form of pellets or granules; It is divided into feedstock recycling, which converts waste plastic into material components needed to manufacture other compounds. Among these, the mechanical recycling method deteriorates the physical properties of products manufactured through the process each time mechanical recycling is repeated, so the feedstock recycling method is preferred as the final recycling method. Feedstock recycling methods are largely divided into pyrolysis, gasification, hydrogenation, and solvolysis, of which pyrolysis is the most actively researched. Pyrolysis oil manufactured from waste plastic through pyrolysis is input into the petroleum refining process and used as a raw material for new chemicals or fuel.

Pyrolysis is one of the feedstock recycling methods and is an eco-friendly waste plastic recycling method that thermally decomposes waste plastic under oxygen-free conditions to produce oil, gas, and char, a solid product. The success or failure of thermal decomposition of waste plastic is directly related to the removal of chlorine or chlorine compounds. Waste plastic generated in cities is mixed with PVC (polyvinyl chloride). Chlorine compounds (HCl, etc.) generated during thermal decomposition of PVC cause corrosion of the process during thermal decomposition, and when pyrolysis oil containing it is burned, incineration facilities are required. It shortens the lifespan and causes dioxin.

In other words, the amount of waste plastic generated is continuously increasing around the world, and pyrolysis technology has the advantage of being able to produce diesel fuel and naphtha raw materials from waste plastic and having a significant CO2 reduction effect. The Ministry of Environment reported that it will increase the proportion of waste plastic generated through pyrolysis treatment by 100 times from the existing 0.1% to 10% by 2030.

Figure 1 shows the configuration of a typical waste plastic pyrolysis process (1). As shown in Figure 1, waste plastic is injected into the pyrolysis furnace 10, and the pyrolyzed gaseous oil vapor is condensed in the heat exchanger 50 at the rear of the process and collected as pyrolysis oil.

Because the condensation temperature is lower than the temperature of the heat exchanger, the oil vapor of the component that cannot be condensed is discharged to the rear of the reactor as a pyrolysis gas. Meanwhile, the oil vapor generated from the thermal decomposition of waste plastic contains various types of hydrocarbon components, and these hydrocarbons have a wide range of carbon atoms, so the temperature range of the boiling and melting points of each component in the oil vapor from the thermal decomposition of waste plastic is wide. Among waste plastic pyrolysis components, those that are in solid form at room temperature are usually referred to as wax.

During the waste plastic pyrolysis process, coolant at room temperature is usually injected into the heat exchanger. Wax, which is solid at room temperature, condenses and solidifies on the outer wall of the heat exchanger, reducing the heat transfer efficiency of the heat exchanger, and in the worst case, the heat exchanger is clogged, making it impossible to operate. It is stopped. This is a problem that frequently occurs in commercial-grade waste plastic pyrolysis facilities.

Republic of Korea registered patent 10-2123842 Republic of Korea registered patent 10-1890415 Republic of Korea registered patent 10-2029047 Republic of Korea registered patent 10-1130337

Therefore, the present invention was developed to solve the above-described conventional problems. According to an embodiment of the present invention, the wax condenses and solidifies on the outer wall of the heat exchanger during the condensation process of the pyrolysis gas of the heat exchanger, reducing the heat exchange efficiency. The purpose is to solve the problem.

According to an embodiment of the present invention, wax can be condensed by increasing the convective heat transfer coefficient through high-speed jet injection, and a wax collection device is installed in front of the heat exchanger, so that the wax is collected and the removed pyrolysis gas is sent to the heat exchanger. The purpose is to provide a gas jet spray pyrolysis wax collection device that can solve problems such as condensation efficiency, pyrolysis oil collection efficiency, and heat exchanger operation interruption, and a waste plastic pyrolysis system and method having the collection device.

Meanwhile, the technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly apparent to those skilled in the art from the description below. It will be understandable.

The first object of the present invention is a device for collecting wax in a process for thermally decomposing waste, comprising: a body configured in the form of a tube; A pyrolysis gas inlet provided on one side of the body into which pyrolysis gas generated through a pyrolysis furnace flows; A high-speed jet gas injection tube located inside the body in the longitudinal direction to spray high-speed jet gas toward the inner wall of the body to condense wax; a wax discharge unit connected to the other side of the body and discharging condensed wax; and a pyrolysis gas discharge path through which the pyrolysis gas from which the wax has been removed is discharged. It can be achieved as a gas jet spray pyrolysis wax collection device.

and a heat supply device that heats the body to prevent the condensed wax from solidifying on the inner wall.

In addition, it may further include a control unit that controls the heat supply device to maintain the inner wall temperature higher than the solidification point of the wax.

And the high-speed jet gas injection pipe is located on the central axis of the body and has a plurality of injection holes formed at specific intervals from each other along the longitudinal direction. It may be characterized in that a high-speed jet gas is sprayed.

In addition, forced convection may be induced using the high-speed gas jet to increase the heat transfer coefficient to condense the wax in the pyrolysis gas.

In addition, the control unit may control a gas supply means for supplying gas to the high-speed jet gas injection pipe to allow the gas jet to reach the inner wall.

Additionally, the waste stream may be characterized as waste plastic.

The second object of the present invention is a waste plastic pyrolysis system, which includes a pyrolysis furnace for pyrolyzing waste plastic; A heat exchanger that condenses the pyrolysis gas generated in the pyrolysis furnace and collects pyrolysis oil; and a wax collecting device for the first purpose mentioned above, which is provided at the front of the heat exchanger and collects wax in the pyrolysis gas. It can be achieved as a waste plastic pyrolysis system using a wax collecting device including a.

It may further include a compressor that compresses the pyrolysis gas uncondensed in the heat exchanger and supplies it to the high-speed jet gas injection pipe of the wax collection device.

A third object of the present invention is a method of pyrolyzing waste plastic, comprising the steps of pyrolyzing waste plastic in a pyrolysis furnace to generate pyrolysis gas; Introducing the pyrolysis gas into the body of the wax collection device; Condensing the wax by spraying high-speed jet gas toward the inner wall of the body through the injection hole of the high-speed jet gas injection tube located inside the body; Condensed wax is discharged to the wax discharge path and collected, and pyrolysis gas from which the wax has been removed flows into the heat exchanger; and condensing the pyrolysis gas in a heat exchanger to collect pyrolysis oil. It can be achieved as a waste plastic pyrolysis method capable of collecting wax, including a step.

In addition, the compressor may further include compressing the uncondensed pyrolysis gas in the heat exchanger and supplying it to the high-speed jet gas injection pipe of the wax collection device.

Additionally, in the step of condensing the wax, forced convection may be induced with the high-speed gas jet to increase the heat transfer coefficient to condense the wax in the pyrolysis gas.

The controller may control a heat supply device that heats the body to maintain the temperature of the inner wall of the body higher than the solidification point of wax, and control the compressor to allow a gas jet to reach the inner wall.

According to the gas jet spray pyrolysis wax collection device according to an embodiment of the present invention, the waste plastic pyrolysis system and method having the collection device, wax condenses and solidifies on the outer wall of the heat exchanger during the pyrolysis gas condensation process of the heat exchanger, thereby improving heat exchange efficiency. The problem of reduction can be solved.

According to the gas jet injection pyrolysis wax collection device according to an embodiment of the present invention, the waste plastic pyrolysis system and method having the collection device, wax can be condensed by increasing the convection heat transfer coefficient through high-speed jet injection, and heat exchange. By installing a wax collection device at the front of the machine, the pyrolysis gas from which the wax is collected and removed is supplied to the heat exchanger, which has the effect of solving problems such as condensation efficiency, pyrolysis oil collection efficiency, and heat exchanger operation interruption.

Meanwhile, the effects that can be obtained from the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description below. You will be able to.

The following drawings attached to this specification illustrate preferred embodiments of the present invention, and serve to further understand the technical idea of the present invention along with the detailed description of the invention, so the present invention is limited only to the matters described in such drawings. It should not be interpreted as such.
1 is a block diagram of a typical waste plastic pyrolysis process;
Figure 2 is a cross-sectional view of a gas jet spray pyrolysis wax collection device according to an embodiment of the present invention;
Figure 3 is a flow chart of a waste plastic pyrolysis method using a gas jet pyrolysis wax collection device according to an embodiment of the present invention;
Figure 4 is a configuration diagram of a waste plastic pyrolysis system using a gas jet pyrolysis wax collection device according to an embodiment of the present invention;
Figure 5 shows a block diagram showing the signal flow of the control unit according to an embodiment of the present invention.

The above objects, other objects, features and advantages of the present invention will be easily understood through the following preferred embodiments related to the attached drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed content will be thorough and complete and so that the spirit of the present invention can be sufficiently conveyed to those skilled in the art.

In this specification, when an element is referred to as being on another element, it means that it may be formed directly on the other element or that a third element may be interposed between them. Also, in the drawings, the thickness of components is exaggerated for effective explanation of technical content.

Embodiments described herein will be explained with reference to cross-sectional views and/or plan views, which are ideal illustrations of the present invention. In the drawings, the thicknesses of films and regions are exaggerated for effective explanation of technical content. Therefore, the shape of the illustration may be changed depending on manufacturing technology and/or tolerance. Accordingly, embodiments of the present invention are not limited to the specific form shown, but also include changes in form produced according to the manufacturing process. For example, an area shown as a right angle may be rounded or have a shape with a predetermined curvature. Accordingly, the regions illustrated in the drawings have properties, and the shapes of the regions illustrated in the drawings are intended to illustrate a specific shape of the region of the device and are not intended to limit the scope of the invention. In various embodiments of the present specification, terms such as first and second are used to describe various components, but these components should not be limited by these terms. These terms are merely used to distinguish one component from another. Embodiments described and illustrated herein also include complementary embodiments thereof.

The terminology used herein is for describing embodiments and is not intended to limit the invention. As used herein, singular forms also include plural forms, unless specifically stated otherwise in the context. As used in the specification, 'comprises' and/or 'comprising' does not exclude the presence or addition of one or more other elements.

In describing specific embodiments below, various specific details have been written to explain the invention in more detail and to aid understanding. However, a reader with sufficient knowledge in the field to understand the present invention can recognize that it can be used without these various specific details. In some cases, it is mentioned in advance that when describing the invention, parts that are commonly known but are not significantly related to the invention are not described in order to prevent confusion without any reason in explaining the invention.

Hereinafter, the configuration and function of the gas jet pyrolysis wax collection device according to an embodiment of the present invention and the waste plastic pyrolysis system having this wax collection device will be described.

First, Figure 2 shows a cross-sectional view of a gas jet spray pyrolytic wax collection device according to an embodiment of the present invention.

The technology according to an embodiment of the present invention is a facility for collecting wax generated in a thermal decomposition reaction. The body 31 of the wax collection device 30 is made in a cylindrical or square shape, a heat supply device 32 is installed on the outside, and a thin high-speed jet gas injection tube 40 has a very small injection hole 42. (Sparger) is installed inside. Recirculating pyrolysis gas or nitrogen compressed by a compressor 60 is injected into the gas supply end 41 of the injection pipe 40, and the injected gas is injected at high speed in the horizontal direction through the small injection hole 42. do. The wax collection device 30 is installed in front of the heat exchanger 50 to prevent wax generated from thermal decomposition from reaching the heat exchanger 50.

The body 31 of the wax collecting device 30 according to an embodiment of the present invention basically has a tubular shape and its cross section may be circular or square. The pyrolysis gas generated through the pyrolysis furnace 10 is introduced through the pyrolysis gas inlet provided on the upper side of the body 31.

And the high-speed jet gas injection pipe 40 is located inside the body 31 in the longitudinal direction and sprays the high-speed jet gas toward the inner wall of the body 31 to condense the wax. That is, the injection pipe 40 is located on the central axis of the body 31, and gas flows in the horizontal direction through a plurality of injection holes 42 formed at specific intervals along the longitudinal direction of the injection pipe 40. It is configured to allow the jet gas to reach the inner wall of the body 31.

In addition, the wax discharge passage 33 is connected to the bottom of the body 31 and is configured to discharge condensed wax, and the pyrolysis gas from which the wax has been removed is discharged through the pyrolysis gas discharge passage 34 and flows into the heat exchanger 50. It is structured as possible.

Additionally, the heat supply device 32 is configured to heat the body 31 to prevent the condensed wax from solidifying on the inner wall.

That is, the temperature sensor 71 may be installed to measure the temperature of the inner wall of the body 31, and the control unit 70 controls the heat supply device 32 based on the temperature value measured by the temperature sensor 71 to measure the temperature of the inner wall of the body 31. The temperature is maintained above the freezing point of the wax.

In addition, the control unit 70 controls the gas supply means for supplying gas to the high-speed jet gas injection pipe 40 so that the gas jet can reach the inner wall.

In an embodiment of the present invention, forced convection is induced with a high-speed gas jet to increase the heat transfer coefficient to condense the wax in the pyrolysis gas.

More specifically, the operating principle of the wax collection equipment is as follows. The energy that must be extracted for condensation of oil vapor generated from thermal decomposition can be expressed as equation 1 below.

[Equation 1]

E : Energy to be extracted for condensation of pyrolysis oil vapor [J]

Q : Heat transfer rate [J/s]

t : Residence time [s]

The heat transfer rate inside the body 31 can be expressed by the following equation, and as a result, the energy that must be extracted for condensing the pyrolysis gas (oil vapor) is expressed as the following equation 2.

[Equation 2]

h: convective heat transfer coefficient [W/m ² K]

A: Pipe inner wall surface area [m ² ]

△T : Temperature difference between the fluid and the inner wall of the body

The larger the value of the convective heat transfer coefficient (h), the greater the energy extracted from oil vapor. The heat transfer coefficient shows a value of about 2 to 25 W/m2K in natural convection, while the heat transfer coefficient shows a value of 25 to 250 W/m2K in forced convection, which is about 10 times higher than that of natural convection. In an embodiment of the present invention, forced convection is induced by a high-speed gas jet injected laterally from the spray pipe 40 to increase the heat transfer coefficient and condense the wax in the pyrolysis gas. Meanwhile, since the wax components condensed in the wax collection device 30 must not solidify on the wall, the heat supply device 32 is used to maintain the inner wall temperature above the solidification point so that the wax can descend to a liquid state.

As a result, the design and operation method of the wax collection facility is as follows, as mentioned above.

(1) The temperature of the inner wall of the body 31 where the heat supply device 32 is installed is maintained at a temperature that allows the wax to flow under the body 31 without solidifying.

(2) The gas flow rate injected into the injection pipe 40 installed inside and the diameter of the injection hole 42 are designed and operated so that the gas jet sprayed at high speed from the injection pipe 40 can reach the inner wall of the device. .

Hereinafter, the waste plastic pyrolysis method and pyrolysis system using the above-mentioned gas jet pyrolysis wax collection device 30 will be described.

First, Figure 3 shows a flowchart of a method for pyrolyzing waste plastic using the gas jet pyrolysis wax collection device 30 according to an embodiment of the present invention. And Figure 4 shows the configuration of a waste plastic pyrolysis system using a gas jet pyrolysis wax collection device according to an embodiment of the present invention. Additionally, Figure 5 shows a block diagram showing the signal flow of the control unit according to an embodiment of the present invention.

The wax collection device 30 mentioned above is installed at the front of the heat exchanger 50 and is configured to allow pyrolysis gas from which wax has been removed to flow into the heat exchanger 50.

The waste plastic system 100 has a pyrolysis furnace 10 that pyrolyzes waste plastic. The pyrolysis gas vapor generated in the pyrolysis furnace 10 is discharged through the discharge part 11, and like a normal pyrolysis system, the heat exchanger 50 condenses the pyrolysis gas generated in the pyrolysis furnace 10 to produce pyrolysis oil. It is configured to capture.

In an embodiment of the present invention, the wax collection device 30 mentioned above is provided in front of the heat exchanger 50 to collect and remove wax in the pyrolysis gas, and then allow the pyrolysis gas from which the wax has been removed to flow into the heat exchanger 50. It is composed.

In addition, the compressor 60 is configured to compress the uncondensed pyrolysis gas discharged from the heat exchanger 50 and supply it to the high-speed jet gas injection pipe 40 of the wax collection device 30.

In the waste plastic pyrolysis method according to an embodiment of the present invention, waste plastic is first pyrolyzed in a pyrolysis furnace 10 to generate pyrolysis gas (S1). Then, this pyrolysis gas is discharged through the discharge part 11, and the carbide is removed by the carbide filter 20 (S2).

Then, the pyrolysis gas flows into the body 31 of the wax collection device 30 (S3).

Then, the gas sprays the high-speed jet gas toward the inner wall of the body 31 through the injection hole 42 of the high-speed jet gas injection pipe 40 located inside the body 31 to condense the wax (S4). That is, forced convection is induced with a high-speed gas jet to increase the heat transfer coefficient and condense the wax in the pyrolysis gas (S5, S6).

As mentioned above, the gas supplied to generate the high-speed gas jet may be configured to be supplied by compressing the pyrolysis gas uncondensed in the heat exchanger 50 by the compressor 60.

Then, the condensed wax is discharged to the wax discharge passage 33 and collected (S7), and the pyrolysis gas from which the wax has been removed flows into the heat exchanger 50 (S8).

Then, the pyrolysis gas is cooled and condensed in the heat exchanger 50, and pyrolysis oil is collected (S9).

In this process, the control unit 70 controls the heat supply device 32 that heats the body 31 to maintain the temperature of the inner wall of the body 31 higher than the solidification point of the wax, and controls the compressor 60 to generate the gas jet above. Allows you to reach the inner wall.

In addition, the apparatus and method described above are not limited to the configuration and method of the above-described embodiments, but all or part of each embodiment can be selectively combined so that various modifications can be made. It may be composed.

1: Configuration of the conventional waste plastic pyrolysis process
10: Pyrolysis furnace
11: Pyrolysis gas discharge unit
20:Carbide filter
30: Wax collection device
31:Body
32: Heat supply device
33: Wax discharge path
34: Pyrolysis gas discharge path
40: Pipe for high-speed jet gas injection (sparger)
41: Gas supply stage
42: Spray hole
50: heat exchanger
60: Compressor
70: Control unit
71: Temperature sensor
100: Waste plastic pyrolysis system using gas jet pyrolysis wax collection device

Claims (13)

A device for collecting wax in the process for thermal decomposition of waste streams,
A body composed of a tubular shape;
A pyrolysis gas inlet provided on one side of the body into which pyrolysis gas generated through a pyrolysis furnace flows;
A high-speed jet gas injection tube located inside the body in the longitudinal direction to spray high-speed jet gas toward the inner wall of the body to condense wax;
a wax discharge unit connected to the other side of the body and discharging condensed wax; and
A gas jet spray pyrolysis wax collection device comprising a pyrolysis gas discharge path through which the pyrolysis gas from which the wax has been removed is discharged.
According to clause 1,
A heat supply device that heats the body to prevent the condensed wax from solidifying on the inner wall. Gas jet spray pyrolysis wax collection device further comprising a.
According to clause 2,
A control unit that controls the heat supply device to maintain the inner wall temperature higher than the solidification point of the wax. Gas jet spray pyrolysis wax collection device.
According to clause 1,
The tube for high-speed jet gas injection is located on the central axis of the body and has a plurality of injection holes formed at specific intervals from each other along the longitudinal direction, and provides high-speed jet gas injection in a direction perpendicular to the longitudinal direction of the body through the injection holes. A gas jet spray pyrolysis wax collection device where jet gas is sprayed.
According to clause 4,
A gas jet spray pyrolysis wax collection device that induces forced convection with the high-speed gas jet to increase the heat transfer coefficient and condense the wax in the pyrolysis gas.
According to clause 5,
The control unit controls a gas supply means for supplying gas to the high-speed jet gas injection pipe to allow the gas jet to reach the inner wall.
According to clause 1,
The waste stream is a waste plastic, a gas jet spray pyrolysis wax collection device.
As a waste plastic pyrolysis system,
A pyrolysis furnace that thermally decomposes waste plastic;
A heat exchanger that condenses the pyrolysis gas generated in the pyrolysis furnace and collects pyrolysis oil; and
A waste plastic pyrolysis system using a wax collection device, comprising: a wax collection device according to any one of claims 1 to 7, which is provided at the front of the heat exchanger and collects wax in the pyrolysis gas.
According to clause 8,
A waste plastic pyrolysis system using a wax collection device, further comprising a compressor that compresses the pyrolysis gas uncondensed in the heat exchanger and supplies it to a high-speed jet gas injection pipe of the wax collection device.
As a method of thermal decomposition of waste plastic,
A step of generating pyrolysis gas by pyrolyzing waste plastic in a pyrolysis furnace;
Introducing the pyrolysis gas into the body of the wax collection device;
Condensing the wax by spraying high-speed jet gas toward the inner wall of the body through the injection hole of the high-speed jet gas injection tube located inside the body;
Condensed wax is discharged to the wax discharge path and collected, and pyrolysis gas from which the wax has been removed flows into the heat exchanger; and
A waste plastic pyrolysis method capable of collecting wax, comprising: condensing pyrolysis gas in a heat exchanger and collecting pyrolysis oil.
According to clause 10,
A method for pyrolyzing waste plastic capable of collecting wax, further comprising the step of having a compressor compress the pyrolysis gas uncondensed in the heat exchanger and supplying it to a high-speed jet gas injection pipe of the wax collection device.
According to clause 11,
In the step of condensing the wax,
A waste plastic pyrolysis method capable of collecting wax, which condenses wax in pyrolysis gas by inducing forced convection with the high-speed gas jet to increase the heat transfer coefficient.
According to clause 12,
A waste plastic pyrolysis method capable of collecting wax, in which the control unit controls a heat supply device that heats the body to maintain the temperature of the inner wall of the body higher than the solidification point of the wax, and controls the compressor to allow a gas jet to reach the inner wall. .

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