Catalytic pyrolysis device for chemical recycling of waste plastics

Abstract

A catalytic pyrolysis device for chemical recycling of waste plastics, the catalytic pyrolysis device comprising a plastic pulverizer (1), wherein a preheating mechanism (2) is fixedly connected to the bottom end of the plastic pulverizer, a feeding mechanism (3) is fixedly connected to the bottom end of the preheating mechanism, a reaction kettle (4) is fixedly connected to a side surface of the feeding mechanism, a catalytic tower (5) is fixedly connected to the side surface of the reaction kettle away from the feeding mechanism, a catalyzed oil-gas pipe (6) is fixedly connected to the top end of the catalytic tower, a waste gas pipe (7) is fixedly connected to the side surface of the reaction kettle, and a shunting mechanism (9) is fixedly connected to the side surface of the waste gas pipe away from the reaction kettle. Waste gas heated in the reaction kettle is directly introduced into a heating jacket (12), and the temperature in the heating jacket rises to heat the catalytic tower, thereby recycling the heat from the waste gas; and the gas introduced into a gas heat exchanger (8) is subjected to heat exchange, and hot gas which has been subjected to heat exchange with clean gas preheats waste plastics.

Description

A catalytic cracking device for chemical recycling of waste plastics Technical Field

[0001] This invention relates to the field of catalytic cracking technology, and more specifically to a catalytic cracking device for the chemical recycling of waste plastics. Background Technology

[0002] Catalytic cracking is a process in which petroleum hydrocarbons are cracked at high temperatures in the presence of a catalyst to produce low-carbon olefins such as ethylene, propylene, and butene, while simultaneously producing light aromatics. Due to the presence of a catalyst, catalytic cracking can lower the reaction temperature, increase the yield of low-carbon olefins and light aromatics, and improve the flexibility of product distribution. Catalytic cracking is the result of the combined effects of carbocation and free radical reaction mechanisms.

[0003] Catalysts are a crucial factor affecting product distribution in catalytic cracking processes. Cracking catalysts should possess high activity and selectivity, ensuring the generation of a large amount of low-carbon olefins during cracking while minimizing the yields of hydrogen, methane, and liquid products. Furthermore, they should exhibit high stability and mechanical strength. Therefore, selecting suitable catalysts is essential. Technical issues

[0004] Currently, in the chemical recycling of waste plastics, the waste plastics are heated and cracked into gas. The cracked gas then undergoes a catalytic reaction with a gaseous catalyst in a catalytic tower. Since the catalytic process is endothermic, the catalytic tower needs to be heated. Both conventional and catalytic cracking of waste plastics require heating, thus current catalytic cracking processes waste significant thermal resources to ensure their smooth operation.

[0005] After the waste plastic is crushed, it is fed into a reactor for heating and gasification. The gasification process requires continuous heating, and since the waste plastic is at a low temperature, it takes a certain amount of time to complete the gasification. Therefore, the overall heating process of the waste plastic is slow, which reduces the overall pyrolysis efficiency. Technical solutions

[0006] In order to overcome the above-mentioned defects of the prior art, embodiments of the present invention provide a catalytic cracking device for chemical recycling of waste plastics to solve the technical problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a catalytic cracking device for chemical recycling of waste plastics, comprising a plastic crusher, a preheating mechanism fixedly connected to the bottom end of the plastic crusher, a feeding mechanism fixedly connected to the bottom end of the preheating mechanism, a reaction vessel fixedly connected to the side of the feeding mechanism, a catalytic tower fixedly connected to the side of the reaction vessel away from the feeding mechanism, a catalytic oil and gas pipe fixedly connected to the top end of the catalytic tower, an exhaust gas pipe fixedly connected to the side of the reaction vessel, and a diversion mechanism fixedly connected to the side of the exhaust gas pipe away from the reaction vessel;

[0008] A preheating pipe is fixedly connected to one side of the diversion mechanism, and a recovery pipe is fixedly connected to the other side of the diversion mechanism. A gas heat exchanger is fixedly connected to the side of the preheating pipe. The side of the preheating pipe away from the diversion mechanism is fixedly connected to the side of the preheating mechanism. A heating jacket is fixedly connected to the side of the recovery pipe away from the diversion mechanism. The heating jacket is fixedly fitted onto the side of the catalytic tower.

[0009] In a preferred embodiment, the diversion mechanism includes an inlet sealing block that can receive exhaust gas, a gas box is fixedly connected to the side of the inlet sealing block, a first sealing plate is fixedly connected to one side of the gas box, a second sealing plate is fixedly connected to the other side of the gas box, the first sealing plate is fixedly connected to a preheating pipe, and the second sealing plate is fixedly connected to a recovery pipe.

[0010] In a preferred embodiment, the gas box has a through groove on the side near the air inlet sealing block. The air inlet sealing block is connected to the inside of the gas box through the groove. A movable block is movably connected to the inside of the gas box. The movable block seals the inside of the gas box and moves along the side of the through groove.

[0011] In a preferred embodiment, the movable block is internally threaded with a threaded rod, a second bevel gear is fixedly connected to the side of the threaded rod, a first bevel gear is fixedly connected to the second bevel gear, a rotating shaft is fixedly connected to the top of the first bevel gear, a rotating wheel is fixedly connected to the top of the rotating shaft, connecting plates are movably connected to both sides of the threaded rod, the bottom end of the connecting plate is fixedly connected to the interior of the gas box, and sliders are fixedly connected to both the top and bottom ends of the movable block, with a sliding groove adapted to the slider inside the slider.

[0012] In a preferred embodiment, the preheating mechanism includes a gas channel for receiving gas from the preheating tube. A plastic pass-through cylinder is fixedly connected inside the gas channel, and a hopper is fixedly connected to the bottom end of the plastic pass-through cylinder. An upper exhaust pipe and a lower exhaust pipe are fixedly connected from top to bottom on the side of the gas channel near the preheating tube. A rotating gear is provided on the inner side of the gas channel opposite to the preheating tube. An upper exhaust pipe, an output inclined pipe, and a lower exhaust pipe are fixedly connected sequentially from top to bottom on the other two sides of the inner side of the gas channel.

[0013] In a preferred embodiment, the plastic tube is movably connected to a connecting shaft inside, a connecting shaft is fixedly connected to the side of the connecting shaft, and a rotating gear is fixedly connected to the side of the connecting shaft away from the rotating plate.

[0014] In a preferred embodiment, the number of the rotating plate, the connecting shaft, and the rotating gear are all four, and the outlet of the output inclined pipe is located on the side of the rotating plate, the outlet of the upper exhaust pipe is located above the rotating plate, and the outlet of the lower exhaust pipe is located below the rotating plate. Beneficial effects

[0015] The technical effects and advantages of this invention are as follows:

[0016] 1. This invention comprises a reaction vessel, a gas heat exchanger, and a heating jacket. Part of the waste gas from the heated reaction vessel is directly introduced into the heating jacket, where the temperature rises to heat the catalytic tower. Catalysis in the catalytic tower is an endothermic process, and the heat from the catalytic process is provided to the waste gas, thus recovering and utilizing the heat in the waste gas to achieve energy saving. The other part is introduced into the gas heat exchanger for heat exchange. After the hot gas exchanges heat with clean gas, the waste plastic is preheated.

[0017] 2. When the rotating wheel of the present invention rotates, the rotation of the rotating wheel drives the threaded rod to rotate through the first bevel gear and the second bevel gear. When the threaded rod rotates, the moving block moves. The moving block moves to the side of the gas box, thereby adjusting the flow rate of gas in the gas box into the preheating pipe and the recovery pipe, giving different amounts of heat to the preheating mechanism and the heating jacket, intelligently adjusting the catalytic cracking process, and improving the processing quality of catalytic cracking.

[0018] 3. In this invention, high-temperature clean gas enters the gas channel and flows through it before being discharged from the inclined output pipe, the upper exhaust pipe, and the lower exhaust pipe. The gas discharged from the inclined output pipe blows onto the rotating plate, causing the rotating plate to rotate. As the rotating plate rotates, it breaks up the pulverized plastic. The upper and lower exhaust pipes preheat the broken plastic from both above and below, allowing it to enter the reaction vessel after preheating, thus improving the four aspects of plastic gasification. Attached Figure Description

[0019] Figure 1 is a schematic diagram of the overall front structure of the present invention.

[0020] Figure 2 is a schematic diagram of the overall back structure of the present invention.

[0021] Figure 3 is a schematic diagram of the gas flow structure after heat exchange inside the reactor of the present invention.

[0022] Figure 4 is a schematic diagram of the overall structure of the diversion mechanism of the present invention.

[0023] Figure 5 is an exploded view of the diversion mechanism of the present invention.

[0024] Figure 6 is a schematic diagram of the preheating mechanism of the present invention.

[0025] Figure 7 is a schematic diagram of the outer cross-sectional structure of the gas channel of the present invention.

[0026] Figure 8 is a schematic cross-sectional view of the gas channel in the present invention.

[0027] Figure 9 is a schematic diagram of the internal structure of the plastic through-tube of the present invention.

[0028] The attached figures are labeled as follows: 1. Plastic crusher; 2. Preheating mechanism; 201. Gas channel; 202. Plastic through cylinder; 203. Feeding hopper; 204. Output inclined pipe; 205. Upper exhaust pipe; 206. Lower exhaust pipe; 207. Rotating plate; 208. Connecting shaft; 209. Rotating gear; 3. Feeding mechanism; 4. Reactor; 5. Catalytic tower; 6. Oil and gas pipe; 7. Waste gas pipe; 8. Gas heat exchanger; 9. Diverting mechanism; 901. Inlet sealing block; 902. Gas box; 903. First sealing plate; 904. Second sealing plate; 905. Through groove; 906. Rotating wheel; 907. Rotating shaft; 908. First bevel gear; 909. Second bevel gear; 910. Threaded rod; 911. Moving block; 912. Sliding block; 913. Connecting plate; 10. Preheating pipe; 11. Recovery pipe; 12. Heating jacket. Embodiments of the present invention

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. In addition, the forms of the various structures described in the following embodiments are merely illustrative. The catalytic cracking device for chemical recycling of waste plastics involved in the present invention is not limited to the structures described in the following embodiments. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Referring to Figures 1, 2, and 3, the present invention provides a catalytic cracking device for chemical recycling of waste plastics, comprising a plastic crusher 1, characterized in that: a preheating mechanism 2 is fixedly connected to the bottom end of the plastic crusher 1, a feeding mechanism 3 is fixedly connected to the bottom end of the preheating mechanism 2, a reaction vessel 4 is fixedly connected to the side of the feeding mechanism 3, a catalytic tower 5 is fixedly connected to the side of the reaction vessel 4 away from the feeding mechanism 3, a catalytic tower 5 is fixedly connected to the top of the catalytic tower 5, a catalytically processed oil and gas pipe 6 is fixedly connected to the top of the catalytic tower 5, an exhaust gas pipe 7 is fixedly connected to the side of the reaction vessel 4, a diversion mechanism 9 is fixedly connected to the side of the exhaust gas pipe 7 away from the reaction vessel 4; a preheating pipe 10 is fixedly connected to one side of the diversion mechanism 9, a recovery pipe 11 is fixedly connected to the other side of the diversion mechanism 9, a gas heat exchanger 8 is fixedly connected to the side of the preheating pipe 10 away from the diversion mechanism 9, the side of the preheating pipe 10 away from the diversion mechanism 9 is fixedly connected to the side of the preheating mechanism 2, and a heating jacket 12 is fixedly connected to the side of the recovery pipe 11 away from the diversion mechanism 9, the heating jacket 12 is fixedly sleeved on the side of the catalytic tower 5.

[0031] In this embodiment, during the catalytic cracking of waste plastics, the reactor 4 performs a plastic gasification process. The high-temperature waste gas generated after gasification flows into the diversion mechanism 9 through the waste gas pipe 7. Part of the gas in the diversion mechanism 9 is introduced into the heating jacket 12. The catalytic reaction in the catalytic tower 5 is an endothermic process. Hot gas is introduced into the heating jacket 12 to provide the heat required for the catalytic reaction, facilitating the catalytic reaction. When the moving block 911 moves, it adjusts the gas flow rate, which can control the temperature in the heating jacket 12, thereby improving the quality of the catalytic reaction. The remaining gas in the diversion mechanism 9 enters the preheating pipe 10 and exchanges heat through the side gas heat exchanger 8. The waste gas exchanges heat with the low-temperature clean gas in the gas heat exchanger 8, at which time the low-temperature clean gas is heated. The heated gas enters the preheating mechanism for preheating. The reactor 4 vaporizes the pulverized plastic and then enters the catalytic tower 5, where it reacts with the vaporized catalyst. After catalysis, the gas is discharged through the oil and gas pipe, thus completing the chemical recovery of the plastic. In addition, it should be noted that the gas heat exchanger 8 is used to introduce clean gas from the side near the diversion mechanism 9. The high-temperature waste gas and the low-temperature clean gas exchange heat in the gas heat exchanger 8. The waste gas after heat exchange is discharged from the gas heat exchanger 8 away from the diversion mechanism 9. The vaporized catalyst is added to the catalytic tower 5 from the bottom. The heating jacket 12 is discharged after the waste gas is introduced. In addition, this is a prior art method in this application, and the discharge pipeline will not be described in detail.

[0032] Referring to Figures 3, 4, and 5, the diversion mechanism 9 includes an inlet sealing block 901 that can receive exhaust gas. A gas box 902 is fixedly connected to the side of the inlet sealing block 901. A first sealing plate 903 is fixedly connected to one side of the gas box 902, and a second sealing plate 904 is fixedly connected to the other side of the gas box 902. The first sealing plate 903 is fixedly connected to the preheating pipe 10, and the second sealing plate 904 is fixedly connected to the recovery pipe 11. A through groove 905 is opened on the side of the gas box 902 near the inlet sealing block 901. The inlet sealing block 901 is connected to the interior of the gas box 902 through the groove 905. A movable block 911 is movably connected to the interior of the gas box 902. The movable block 911 moves the gas box 902... The internal seal of 02 is provided, and the moving block 911 moves along the side of the passage groove 905. The moving block 911 is internally threaded with a threaded rod 910. The side of the threaded rod 910 is fixedly connected with a second bevel gear 909. The second bevel gear 909 is fixedly connected with a first bevel gear 908. The top of the first bevel gear 908 is fixedly connected with a rotating shaft 907. The top of the rotating shaft 907 is fixedly connected with a rotating wheel 906. The two sides of the threaded rod 910 are movably connected with connecting plates 913. The bottom of the connecting plate 913 is fixedly connected to the inside of the gas box 902. The top and bottom of the moving block 911 are both fixedly connected with sliders 912. The inside of the slider 912 is provided with a sliding groove that matches the slider 912.

[0033] In this embodiment, clean, high-temperature gas enters the gas chamber 902 through the inlet sealing block 901 and the through groove 905. When the gas passes through the through groove 905, the moving block 911 divides the through groove 905 into two parts, so the gas enters both sides of the gas chamber 902 and is then discharged from the first sealing plate 903 and the second sealing plate 904, respectively, and supplied to the preheating mechanism 2 and the heating jacket 12. After rotating the rotating wheel 906, the threaded rod 910 rotates. When the threaded rod 910 rotates, 914 moves. After 914 moves, it adjusts the amount of gas discharged from the first sealing plate 903 and the second sealing plate 904, thereby adjusting the preheating effect in the preheating mechanism 2 and the heating temperature of the heating jacket 12, making the preheating mechanism 2 and the heating jacket 12 work more precisely, thereby improving the quality of catalytic cracking. When the moving block 911 moves, it drives the slider 912 to move. The slider 912 moves in the groove of the gas chamber 902, making the movement of the moving block 911 more stable.

[0034] Referring to Figures 6, 7, 8, and 9, the preheating mechanism 2 includes a gas channel 201 for receiving gas from the preheating tube 10. A plastic pass-through cylinder 202 is fixedly connected inside the gas channel 201, and a hopper 203 is fixedly connected to the bottom end of the plastic pass-through cylinder 202. An upper exhaust pipe 205 and a lower exhaust pipe 206 are fixedly connected from top to bottom on the side of the gas channel 201 near the preheating tube 10. A rotating gear 209 is provided on the inner side of the gas channel 201 opposite to the preheating tube 10. The remaining two sides of the inner side of the gas channel 201 are fixedly connected from top to bottom to the upper exhaust pipe 206. 5. The output inclined pipe 204 and the lower exhaust pipe 206 are connected to the plastic tube 202 via a connecting shaft 208. The connecting shaft 208 is fixedly connected to the side of the connecting shaft 208. A rotating gear 209 is fixedly connected to the side of the connecting shaft 208 away from the rotating plate 207. There are four rotating plates 207, four connecting shafts 208, and four rotating gears 209. The outlet of the output inclined pipe 204 is located on the side of the rotating plate 207, the outlet of the upper exhaust pipe 205 is located above the rotating plate 207, and the outlet of the lower exhaust pipe 206 is located below the rotating plate 207.

[0035] In this embodiment, gas enters the gas channel 201 through the preheating pipe 10, flows within the gas channel 201, and is discharged from the upper exhaust pipe 205, the output inclined pipe 204, and the lower exhaust pipe 206. Four rotating plates 207 are located inside the plastic through-tube 202. Since the rotation direction of the rotating plates 207 is limited, the output inclined pipe 204 is not provided on the side where the rotating plates 207 cannot rotate (i.e., the side where the preheating pipe 10 is located and the side opposite the preheating pipe 10). On the other two sides, output inclined pipes 204 are provided to allow the rotating plates 207 to rotate. When the rotating plate 207 rotates, the rotating gears 209 on both sides will rotate synchronously, driving the inner rotating gear 209 to rotate. All four rotating plates 207 will rotate. After rotating a certain angle, the rotating plate 207 will reset and be blown by the output inclined pipe 204 again. Therefore, the rotating plate 207 will rotate back and forth, thereby shaking the plastic that falls on the rotating plate 207 up and down, breaking up the crushed plastic. After breaking up, the upper exhaust pipe 205 and the lower exhaust pipe 206 preheat the plastic located above and below the rotating plate 207, respectively, so that the plastic has a high temperature before entering the reaction vessel 4, which facilitates the gasification process.

[0036] The working principle of this invention is as follows: Waste plastic is added into a plastic crusher 1 and crushed. After being preheated by a preheating mechanism 2, the crushed plastic is added into a feeding mechanism 3 and fed into a reaction vessel 4. The reaction vessel 4 vaporizes the crushed plastic and the vaporized plastic enters a catalytic tower 5. The catalyst from the vaporization is added into the catalytic tower 5 through an oil and gas pipe 6 to carry out a catalytic reaction, thereby completing the chemical recycling of the plastic.

[0037] During the plastic gasification process in reactor 4, the generated high-temperature waste gas flows into the diversion mechanism 9 through the waste gas pipe 7. The waste gas entering the diversion mechanism 9 passes through the inlet sealing block 901 and the groove 905 into the gas box 902. As the gas enters the gas box 902, it rotates the rotating wheel 906, which in turn drives the rotating shaft 907. The rotation of the rotating shaft 907, in turn, drives the threaded rod 910 to rotate via the first bevel gear 908 and the second bevel gear 909. The rotation of the threaded rod 910 causes the moving block 911 to move. The moving block 911 moves to the side of the gas box 902, changing the opening area of ​​the two parts of the gas box 902, thereby adjusting the amount of gas entering the preheating pipe 10 and the recovery pipe 11. The gas entering the recovery pipe 11 will be introduced into the heating jacket 12. The catalytic reaction in the catalytic tower 5 is an endothermic process. Hot gas is introduced into the heating jacket 12 to provide the heat required for the catalytic reaction, which facilitates the catalytic reaction. When the moving block 911 moves, it adjusts the gas flow rate, which can control the temperature in the heating jacket 12, thereby improving the quality of the catalytic reaction.

[0038] The high-temperature gas entering the preheating tube 10 exchanges heat with the low-temperature clean gas in the gas heat exchanger, transforming the low-temperature clean gas into high-temperature clean gas, which then enters the gas channel 201. After flowing within the gas channel 201, the gas is discharged into the plastic passage cylinder 202 through the output inclined pipe 204, the upper exhaust pipe 205, and the lower exhaust pipe 206. The output inclined pipe 204 is in an inclined state, so the gas flowing out from the output inclined pipe 204 blows onto the surface of the rotating plate 207. The surface of the rotating plate 207 rotates under the action of the gas. When the rotating plate 207 rotates, it drives the rotating gear 209 to rotate through the connecting shaft 208. When the rotating gears 209 on both sides rotate, they synchronously drive the inner rotating gear 209 to rotate. At this time, all four rotating plates 207 will rotate. When the rotating plate 207 rotates to a certain angle, it will reset and be blown by the output inclined pipe 204 again, so the rotating plate 207 will rotate back and forth, thereby shaking the plastic that falls on the rotating plate 207 up and down. Some of the plastic will fall directly through the rotating plate 207. The upper exhaust pipe 205 and the lower exhaust pipe 206 are respectively located above and below the rotating plate 207. Therefore, the upper exhaust pipe 205 heats the plastic that is shaken to the top, and the lower exhaust pipe 206 heats the plastic that falls to the bottom. The rotating plate 207 can also shake the plastic to improve the preheating effect. After the preheated plastic enters the reactor 4, the heating time of the reactor 4 is reduced, and the problem of large temperature difference between the newly added plastic and the heated plastic, which would affect the heating, can be avoided.

[0039] In conclusion, the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A catalytic cracking device for chemical recycling of waste plastics, comprising a plastic crusher (1), characterized in that: The bottom end of the plastic crusher (1) is fixedly connected to a preheating mechanism (2), the bottom end of the preheating mechanism (2) is fixedly connected to a feeding mechanism (3), the side of the feeding mechanism (3) is fixedly connected to a reaction vessel (4), the side of the reaction vessel (4) away from the feeding mechanism (3) is fixedly connected to a catalytic tower (5), the top of the catalytic tower (5) is fixedly connected to a catalytically catalyzed oil and gas pipe (6), the side of the reaction vessel (4) is fixedly connected to a waste gas pipe (7), and the side of the waste gas pipe (7) away from the reaction vessel (4) is fixedly connected to a diversion mechanism (9). A preheating pipe (10) is fixedly connected to one side of the diversion mechanism (9), and a recovery pipe (11) is fixedly connected to the other side of the diversion mechanism (9). A gas heat exchanger (8) is fixedly connected to the side of the preheating pipe (10). The side of the preheating pipe (10) away from the diversion mechanism (9) is fixedly connected to the side of the preheating mechanism (2). A heating jacket (12) is fixedly connected to the side of the recovery pipe (11) away from the diversion mechanism (9). The heating jacket (12) is fixedly sleeved on the side of the catalytic tower (5).

2. The catalytic cracking device for chemical recycling of waste plastics according to claim 1, characterized in that: The diversion mechanism (9) includes an air intake sealing block (901) that can receive exhaust gas. A gas box (902) is fixedly connected to the side of the air intake sealing block (901). A first sealing plate (903) is fixedly connected to one side of the gas box (902). A second sealing plate (904) is fixedly connected to the other side of the gas box (902). The first sealing plate (903) is fixedly connected to the preheating pipe (10), and the second sealing plate (904) is fixedly connected to the recovery pipe (11).

3. The catalytic cracking device for chemical recycling of waste plastics according to claim 2, characterized in that: The gas box (902) has a through groove (905) on the side near the air inlet sealing block (901). The air inlet sealing block (901) is connected to the inside of the gas box (902) through the groove (905). A movable block (911) is movably connected to the inside of the gas box (902). The movable block (911) seals the inside of the gas box (902) and moves on the side of the through groove (905).

4. The catalytic cracking device for chemical recycling of waste plastics according to claim 3, characterized in that: The movable block (911) is internally threaded with a threaded rod (910). A second bevel gear (909) is fixedly connected to the side of the threaded rod (910). A first bevel gear (908) is fixedly connected to the second bevel gear (909). A rotating shaft (907) is fixedly connected to the top of the first bevel gear (908). A rotating wheel (906) is fixedly connected to the top of the rotating shaft (907). A connecting plate (913) is movably connected to both sides of the threaded rod (910). The bottom end of the connecting plate (913) is fixedly connected to the inside of the gas box (902). A slider (912) is fixedly connected to both the top and bottom of the movable block (911). A sliding groove adapted to the slider (912) is opened inside the slider (912).

5. The catalytic cracking device for chemical recycling of waste plastics according to claim 1, characterized in that: The preheating mechanism (2) includes a gas channel (201) for receiving gas from the preheating tube (10). A plastic pass-through cylinder (202) is fixedly connected inside the gas channel (201). A hopper (203) is fixedly connected to the bottom end of the plastic pass-through cylinder (202). An upper exhaust pipe (205) and a lower exhaust pipe (206) are fixedly connected from top to bottom on the side of the gas channel (201) near the preheating tube (10). A rotating gear (209) is provided on the inner side of the gas channel (201) opposite to the preheating tube (10). The other two sides of the inner side of the gas channel (201) are fixedly connected from top to bottom to the upper exhaust pipe (205), the output inclined pipe (204), and the lower exhaust pipe (206).

6. The catalytic cracking device for chemical recycling of waste plastics according to claim 5, characterized in that: The plastic tube (202) is movably connected to the inside of the tube (202), and the side of the connecting shaft (208) is fixedly connected to the connecting shaft (208). The side of the connecting shaft (208) away from the rotating plate (207) is fixedly connected to the rotating gear (209).

7. The catalytic cracking device for chemical recycling of waste plastics according to claim 6, characterized in that: The number of rotating plates (207), connecting shafts (208) and rotating gears (209) are all four. The outlet of the output inclined pipe (204) is located on the side of the rotating plate (207), the outlet of the upper exhaust pipe (205) is located above the rotating plate (207), and the outlet of the lower exhaust pipe (206) is located below the rotating plate (207).

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