A high-efficiency pyrolysis device for waste rubber and plastic with heat transfer enhancement and grinding function

Abstract

The present invention relates to a waste rubber and plastic efficient pyrolysis device with heat transfer enhancement coupled grinding function, belonging to the technical field of harmless treatment and resource utilization of solid waste. It comprises a support and a pyrolysis cylinder arranged on the support, wherein the pyrolysis cylinder is provided with: a pyrolysis chamber, which is arranged along the axial direction of the pyrolysis cylinder, wherein a screw is installed in the pyrolysis chamber, wherein the central axis of the screw is a hollow axis, wherein the central axis is sequentially divided into a same diameter section and a variable diameter section from the feed port, wherein the central axis diameter of the variable diameter section gradually increases; wherein a reverse spiral is provided at the end of the screw of the variable diameter section; a feed unit, which is used for feeding waste rubber and plastic; an internal heating unit, which is used for heating from the cavity of the central axis of the screw; an external heating unit, which is used for heating from the outside of the screw; a pyrolysis gas outlet, which is used for discharging pyrolysis gas of waste rubber and plastic; and a pyrolysis carbon black outlet, which is used for discharging pyrolysis carbon black. By simultaneously heating the inside and outside, the heat transfer and pyrolysis of waste rubber and plastic are enhanced, thereby improving the pyrolysis efficiency of waste rubber and plastic.

Description

Technical Field

[0001] The invention relates to the technical field of harmless treatment and resource utilization of solid waste, and in particular to a waste rubber and plastic high-efficiency pyrolysis device with heat transfer enhancement coupled grinding function. Background Art

[0002] At present, the comprehensive utilization of waste tires mainly includes direct utilization of waste tire prototypes, thermal decomposition, retreading of old tires, production of recycled rubber, and production of vulcanized rubber powder. The products of thermal cracking of waste tires include pyrolysis oil, pyrolysis gas, and pyrolysis carbon black. Among them, the pyrolysis gas is used as pyrolysis fuel, and the excess pyrolysis gas is led to the exhaust gas combustion chamber for combustion and then discharged. Compared with other forms of recycling, waste tire pyrolysis has the advantages of energy saving and high resource recovery rate. More importantly, waste tire pyrolysis has no requirements for the original tires, has a wide adaptability, has the advantages of large processing capacity, high efficiency and low environmental pollution, and is more in line with the concept of energy saving and environmental protection. It is considered to be one of the best ways to deal with waste tires today.

[0003] The existing waste tire pyrolysis technologies include moving bed pyrolysis process, fluidized bed pyrolysis process and rotary continuous pyrolysis process. The moving bed pyrolysis process is a slow pyrolysis process. This pyrolysis technology can reduce the secondary reaction of pyrolysis intermediates, thereby increasing the yield of pyrolysis oil; low pressure is conducive to reducing carbon-containing residues attached to pyrolysis carbon, thereby increasing the possibility of its reuse as carbon black; the pyrolysis oil has a high content of light naphtha and aromatic compounds, which not only improves the economy, but also helps to increase the octane number of fuel oil; it can process large pieces of waste tires without removing steel wire and fiber cords. The disadvantage is that the heating method of the pyrolysis furnace is external heating, the heat transfer efficiency is low, and the entire system cannot work at full load. The fluidized bed pyrolysis process is a fast pyrolysis process, which is characterized by fast heating rate, rapid reaction, and short gas phase residence time, so it has high heat utilization efficiency, and can reduce the occurrence of secondary reactions at the same time, and the yield of pyrolysis oil is high. However, this technology has extremely high requirements for raw materials. The pyrolysis raw materials are waste tire particles with a particle size of less than 5 cm and without steel wires. The products are fuel oil and pyrolysis carbon black. The rotary kiln pyrolysis process is divided into external heating (indirect heating) and internal heating (direct contact heating). The external heating pyrolysis process has a high yield of pyrolysis oil, high calorific value, good carbon black quality, high calorific value of fuel gas, and less pollution emissions than the internal heating pyrolysis process. The rotary kiln pyrolysis process has the characteristics of wide adaptability to the form, shape and size of waste materials. It is suitable for almost any solid waste material and has almost no requirements for the size of waste tire feed. It is a slow pyrolysis process. The disadvantages are low pyrolysis efficiency, secondary reaction of pyrolysis gas at high temperature, easy coking, and large equipment. Summary of the invention

[0004] The purpose of the present invention is to provide a high-efficiency pyrolysis device for waste rubber and plastic with heat transfer enhancement coupled with grinding function. The device adopts a spiral pyrolysis structure with grinding function. The waste rubber and plastic are squeezed during the transportation and pyrolysis process, and the grinding and heating wall friction accelerates the pyrolysis. The device also has a self-cleaning effect to avoid coking and deterioration of heat transfer.

[0005] In order to achieve the above-mentioned purpose, the waste rubber and plastic efficient pyrolysis device with heat transfer enhancement coupled grinding function provided by the present invention comprises a support and a pyrolysis cylinder arranged on the support, wherein the pyrolysis cylinder is provided with:

[0006] A pyrolysis chamber is arranged along the axial direction of the pyrolysis cylinder, and a screw is installed in the pyrolysis chamber. The central axis of the screw is a hollow shaft. The central axis is divided into a same diameter section and a reduced diameter section from the feed inlet. The central axis diameter of the reduced diameter section gradually increases. The end of the screw of the reduced diameter section is provided with a reverse spiral.

[0007] Feeding unit, used for feeding waste rubber and plastic;

[0008] An internal heating unit, which heats from the cavity of the central axis of the screw;

[0009] An external heating unit is used to heat the outer side of the screw;

[0010] Pyrolysis gas outlet, used to discharge pyrolysis gas of waste rubber and plastic;

[0011] The pyrolytic carbon black outlet is used to discharge the pyrolytic carbon black.

[0012] In the above technical scheme, the heat transfer and pyrolysis of waste rubber and plastic are enhanced by heating both inside and outside at the same time, thereby improving the pyrolysis efficiency of waste rubber and plastic. According to the pyrolysis characteristics of waste rubber and plastic, an internal and external countercurrent arrangement can be set up to improve the quality of the pyrolysis products. The carbon black in the pyrolysis gas is effectively separated by the reverse spiral structure at the end to avoid carbon deposition and blockage problems. Through the spiral pyrolysis structure with grinding function, the waste rubber and plastic are squeezed during the transportation and pyrolysis process, and the grinding and heating wall friction accelerates the pyrolysis, and has a self-cleaning effect to avoid coking and deterioration of heat transfer.

[0013] Optionally, in one embodiment, the central axis is provided with a double-layer cavity, and the internal heating unit includes a smoke inlet and a smoke outlet arranged at the same end of the central axis, the smoke inlet is connected to the outer cavity of the central axis, and the smoke outlet is connected to the inner cavity of the central axis; the inner cavity is connected to the outer cavity at the other end.

[0014] Optionally, in one embodiment, the outer cavity is provided with heat transfer fins; the high-temperature flue gas first enters the inner heating unit, is discharged after heat exchange, and then enters the outer heating unit; the flow direction of the high-temperature flue gas is opposite to the movement direction of the waste rubber and plastic.

[0015] Optionally, in one embodiment, the external heating unit includes a heating cylinder arranged outside the pyrolysis cylinder, a smoke channel is formed between the heating cylinder and the pyrolysis cylinder, and a smoke inlet is provided at one end of the heating cylinder and a smoke outlet is provided at the other end.

[0016] High-temperature flue gas heating is adopted. The high-temperature flue gas first enters the inner heating module, is discharged after heat exchange, and then enters the outer heating module. In the inner heating unit, heat transfer strengthening fins are set to increase the flue gas flow rate, increase the heat transfer area, and strengthen the heat transfer on the one hand, and make the flue gas velocity field uniform on the other hand to avoid local hot spots. The inner heating unit and the outer heating unit are set to heat the waste rubber and plastic at the same time, which greatly strengthens the heat transfer. In particular, there is a conveying spiral on the waste rubber and plastic side of the inner heating unit, which is equivalent to a fin. This has an obvious heat transfer strengthening effect on the waste rubber and plastic side with a low heat transfer coefficient. The high-temperature flue gas first enters the inner heating module and then enters the outer heating unit. This is because there is a conveying spiral on the waste rubber and plastic side of the inner heating unit, the heat exchange area is large, and the higher temperature is conducive to strengthening the heat transfer. At the same time, the flue gas after heat exchange enters the outer heating unit, so that the outer wall temperature of the outer heating module is low, and the heat dissipation loss is small.

[0017] In addition, the flow direction of the flue gas is opposite to the movement direction of the waste rubber and plastic, which can improve the quality of the hot gas product. The temperature at the inlet of the waste rubber and plastic is low, and the temperature at the outlet of the pyrolysis carbon black is high. In the initial stage of pyrolysis of waste rubber and plastic, more pyrolysis gas is precipitated. The lower temperature can avoid the degree of pyrolysis gas cracking and improve the oil yield. When the pyrolysis is basically completed, the higher temperature can ensure the complete pyrolysis of the waste rubber and plastic. On the other hand, the higher the temperature, the lower the ability of the pyrolysis carbon black to adsorb pyrolysis gas, which can reduce the oil content of the pyrolysis carbon black.

[0018] In order to prevent the leakage of pyrolysis gas and high-temperature flue gas, optionally, in one embodiment, the pyrolysis cylinder is further provided with a sealing unit, the sealing unit comprising a front pyrolysis gas sealing component arranged at the feed end of the pyrolysis cylinder, a rear pyrolysis gas sealing component arranged at the outlet end of the pyrolysis cylinder, and a flue gas sealing component;

[0019] The front pyrolysis gas sealing assembly adopts a graphite packing sealing structure; the rear pyrolysis gas sealing assembly and the flue gas sealing assembly adopt a double sealing structure of graphite packing combined with nitrogen sealing, including graphite packing, nitrogen inlet pipe and nitrogen chamber, and the nitrogen flow is monitored to determine whether the sealing structure is intact. During the operation of the pyrolysis device, the nitrogen pressure is kept constant. If the nitrogen flow rate rises suddenly or increases significantly compared to the initial flow rate, it means that the seal is damaged, otherwise the seal is intact.

[0020] In order to accurately control the temperature of the pyrolysis system and monitor the operating status of the pyrolysis device, optionally, in one embodiment, a plurality of temperature measuring points, pressure measuring points and flow measuring points are arranged on the pyrolysis cylinder to monitor and control the pyrolysis temperature, pyrolysis chamber pressure and nitrogen flow.

[0021] Optionally, in one embodiment, the feeding unit includes a hopper and a feeding screw vertically arranged in the hopper, a gate valve is provided at the bottom of the hopper, and the feeding screw is driven by a variable frequency motor for feeding. The feeding screw can reduce the amount of air brought into the pyrolysis device by the waste rubber and plastic feeding, reduce the gap between the waste rubber and plastic, and exhaust the air. A gate valve is provided below the feeding screw for easy maintenance.

[0022] Optionally, in one embodiment, a power unit for driving the screw to rotate is provided on the support, and the power unit includes a variable frequency motor, a reducer, a coupling and a thrust bearing, and also includes a supporting wheel arranged at the other end of the pyrolysis cylinder.

[0023] Optionally, in one embodiment, the length ratio of the same diameter section to the variable diameter section of the screw is 1:1; the spiral tooth height at the end of the variable diameter section is half of the spiral tooth height of the same diameter section. The same diameter section refers to the section in which the diameter of the central axis of the screw remains unchanged, while the variable diameter section refers to the section in which the diameter of the central axis of the screw gradually increases and the corresponding tooth height decreases. During the pyrolysis process, the waste rubber and plastic particles are first pyrolyzed by heat on the outside, and then expand after being heated. Under the rotation and extrusion of the spiral, they are more dense, which is conducive to the conduction of heat; At the same time, the spiral rotates, and the waste rubber and plastic particles are subjected to the circumferential shear force, and the particles rub and mix with each other, and the pyrolyzed part of the outer layer is easy to peel off, which is conducive to the pyrolysis of the waste rubber and plastic particles. Generally, the mass of pyrolytic carbon black in the pyrolysis products of waste rubber and plastic particles accounts for 35% to 40%. As the waste rubber and plastic particles are pyrolyzed, their volume decreases, so the diameter of the second half of the spiral gradually increases, the tooth height and tooth spacing decrease, which promotes the grinding of pyrolytic carbon black and reduces the particle size of pyrolytic carbon black, so that the waste rubber and plastic particles can be fully heated and pyrolyzed.

[0024] In order to complete the transportation of waste rubber and plastic in the pyrolysis device and increase the heat exchange area, it is preferred that the pitch of the spur helical teeth is about 1.5 times the tooth height and can be gradually reduced.

[0025] Optionally, in one embodiment, the reverse spiral is located at the rear of the pyrolytic carbon black outlet and is composed of 3 to 4 teeth. The spiral pyrolysis structure is adopted to complete the transportation of waste rubber and plastic in the pyrolysis device on the one hand, and on the other hand, the waste rubber and plastic expand and extrude during the transportation and pyrolysis process, and advance in a spiral manner, rubbing against the heated wall surface, which has a self-cleaning effect and can avoid coking of the heated wall surface. The pyrolysis gas discharges from the pyrolysis device at a certain speed. Arranging a reverse spiral at the end can reduce the amount of carbon black carried by the pyrolysis gas. The pyrolysis gas flows around in the reverse spiral structure to effectively separate the pyrolytic carbon black. At the same time, the reverse spiral rotates to transport the separated pyrolytic carbon black to the pyrolytic carbon black discharge port.

[0026] Optionally, in one embodiment, the support includes a platform base, a front base, a front support plate, a rear base and a rear support plate. In order to facilitate the installation and transportation of the device, an integrated design is adopted, and the pyrolysis device and auxiliary machines are arranged on the support, and the platform base is used to realize the overall transportation. The front support plate and the rear support plate support the pyrolysis device, and the front base and the rear base are used to install the power unit and the pipeline.

[0027] Under higher pyrolysis efficiency, waste rubber and plastic can be pyrolyzed quickly, and its residence time in the pyrolysis device can be shortened. The power unit can adjust the speed of the variable frequency motor to control the rotation speed of the pyrolysis spiral at 3 to 5 revolutions per minute. The residence time of waste rubber and plastic in the pyrolysis chamber is 10 to 15 minutes. The short residence time can avoid the pyrolysis oil and gas from staying in the pyrolysis chamber for a long time to cause secondary reactions to generate lower-quality heavy oil and small-molecule pyrolysis gas, thereby increasing the yield of pyrolysis oil.

[0028] Compared with the prior art, the present invention is beneficial in that:

[0029] The pyrolysis device of the present invention has the advantages of high pyrolysis efficiency, short residence time, excellent pyrolysis product quality, compact equipment, low investment cost, self-cleaning function, long operation cycle, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic structural diagram of a waste rubber and plastic efficient pyrolysis device with heat transfer enhancement coupled with grinding function in an embodiment of the present invention. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described below in conjunction with the embodiments and the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the described embodiments, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] Unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "including" or "comprising" and the like used in the present invention mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. The words "connect" or "connected" and the like are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right", etc. are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0033] Example

[0034] See also Figure 1 In this embodiment, the high-efficiency pyrolysis device for waste rubber and plastic with heat transfer enhancement coupled grinding function includes: a support, a pyrolysis cylinder, a power unit, a feeding unit, an internal heating unit, an external heating unit, a sealing unit, a pyrolysis gas outlet 7 and a pyrolysis carbon black outlet 8.

[0035] Among them, the support is used to support the pyrolysis device and install auxiliary equipment, including a platform base 101, a front base 102, a front support plate 103, a rear base 104 and a rear support plate 105. The power unit is used to drive the screw to rotate, including a variable frequency motor 201, a reducer 202, a coupling 203, a thrust bearing 204 and a support wheel 205. The feeding unit is used to feed waste rubber and plastic, including a hopper 301, a variable frequency motor 302, a feeding screw 303, a gate valve 304 and a feeding port 305. The pyrolysis cylinder is provided with an axial pyrolysis chamber 401, and a screw is installed in the pyrolysis chamber 401. The screw is provided with a conveying positive screw 402 and an end reverse screw 403, and the screw includes a same diameter section 404 and a reduced diameter section 405. The internal heating unit is used to heat the waste rubber and plastic from the inside to promote pyrolysis, including a smoke inlet 501, a heat transfer strengthening fin 503, a smoke outlet pipe 505 and a smoke outlet 506, and the smoke flow direction is shown as 502 and 504. The external heating unit is used to heat the waste rubber and plastic from the outside to promote pyrolysis, including a smoke inlet 601, a smoke flow channel 602 and a smoke outlet 604, and the smoke flow direction is shown as 603. The sealing unit is used to seal the pyrolysis gas and smoke chamber of the pyrolysis device, including a front pyrolysis gas sealing component 901, a rear pyrolysis gas sealing component and a smoke seal, wherein the rear pyrolysis gas seal includes a graphite packing 9021, a nitrogen pipeline 9022 and a nitrogen chamber 9023, and the smoke seal includes a graphite packing 9031, a nitrogen pipeline 9032 and a nitrogen chamber 9033. The pyrolysis gas outlet 7 is used to discharge the pyrolysis gas of the waste rubber and plastic; the pyrolysis carbon black outlet 8 is used to discharge the pyrolysis carbon black.

[0036] The pyrolysis device of this embodiment adopts an integrated design to facilitate the installation and transportation of the equipment. The pyrolysis device and auxiliary equipment are arranged on the support and transported as a whole through the platform base 101. The front support plate 103 and the rear support plate 105 support the pyrolysis device, and the front base 102 and the rear base 104 are used to install the power unit and pipelines.

[0037] At a higher pyrolysis efficiency, waste rubber and plastic can be pyrolyzed quickly, and its residence time in the pyrolysis device can be shortened. The power unit can adjust the speed of the variable frequency motor to control the pyrolysis spiral rotation speed at 3 to 5 rpm, and the waste rubber and plastic stay in the pyrolysis chamber 401 for 10 to 15 minutes.

[0038] This embodiment uses a feeding screw 303 to squeeze the feed, reduce the gap between the waste rubber and plastic, exhaust the air, and reduce the amount of air brought into the pyrolysis device by the waste rubber and plastic feed. A gate valve 304 is provided below the feeding screw 303 for easy maintenance.

[0039] In this embodiment, a conveying positive spiral 402 and an end reverse spiral 403, a same diameter section 404 and a reduced diameter section 405 are arranged on the screw, so that the waste rubber and plastic can be pyrolyzed while advancing in the pyrolysis device, and at the same time reduce the content of pyrolytic carbon black in the pyrolysis gas. The conveying positive spiral 402 and the end reverse spiral 403 have opposite rotation directions. The end reverse spiral 403 is located at the rear of the pyrolytic carbon black outlet 8 and consists of 3 to 4 teeth. The spiral pyrolysis structure is adopted to complete the conveying of the waste rubber and plastic in the pyrolysis device on the one hand, and on the other hand, the waste rubber and plastic expand and squeeze during the conveying pyrolysis process, advance in a spiral manner, and rub against the heated wall surface, which has a self-cleaning effect and can avoid coking of the heated wall surface. The pyrolysis gas discharges from the pyrolysis device at a certain speed. In order to reduce the amount of carbon black carried by the pyrolysis gas, a reverse spiral is arranged at the end, and the pyrolysis gas flows around in the reverse spiral structure to effectively separate the pyrolytic carbon black. At the same time, the reverse spiral rotates and conveys the separated pyrolytic carbon black to the pyrolytic carbon black discharge port 8. The tooth spacing of the conveying positive spiral 402 is set to be approximately 1.5 times the tooth height and gradually decreases to complete the conveyance of the waste rubber and plastic in the pyrolysis device and increase the heat exchange area.

[0040] This embodiment uses a variable diameter screw for conveying, heating, extruding, and grinding waste rubber and plastic particles. The length ratio of the same diameter section 404 and the variable diameter section 405 of the screw is 1:1, which can achieve rapid pyrolysis of waste rubber and plastic particles. The same diameter section here means that the diameter of the central axis of the screw in this section remains unchanged, while the variable diameter section means that the diameter of the central axis of the screw gradually increases and the corresponding tooth height decreases. During the pyrolysis process, the waste rubber and plastic particles are first pyrolyzed by heat on the outside, and then expand after being heated. They are more dense under the rotation and extrusion of the screw, which is conducive to the conduction of heat. At the same time, the screw rotates, and the waste rubber and plastic particles are subjected to the circumferential shear force. The particles rub against each other and mix, and the pyrolyzed part of the outer layer is easy to peel off, which is conducive to the pyrolysis of the waste rubber and plastic particles. Generally, the mass of pyrolytic carbon black in the pyrolysis products of waste rubber and plastic particles accounts for 35% to 40%. As the waste rubber and plastic particles are pyrolyzed, their volume decreases, so the diameter of the second half of the screw shaft gradually increases, and the tooth height and tooth spacing decrease, which promotes the grinding of pyrolytic carbon black and reduces the particle size of pyrolytic carbon black, so that the inside of the waste rubber and plastic particles can be fully heated and pyrolyzed.

[0041] In this embodiment, both the internal heating unit and the external heating unit adopt the high-temperature flue gas heating method. The high-temperature flue gas first enters the internal heating unit, is discharged after heat exchange, and then enters the external heating unit. In the internal heating unit, a heat transfer strengthening fin 503 is set to increase the flue gas flow rate, increase the heat transfer area, and strengthen the heat transfer on the one hand, and make the flue gas velocity field uniform to avoid the occurrence of local hot spots on the other hand. The internal heating unit and the external heating unit are set to heat the waste rubber and plastic at the same time, which greatly strengthens the heat transfer. In particular, the waste rubber and plastic side of the internal heating unit has a conveying spiral, which is equivalent to a fin. This has an obvious heat transfer strengthening effect on the waste rubber and plastic side with a low heat transfer coefficient. The high-temperature flue gas first enters the internal heating unit and then enters the external heating unit. This is because the waste rubber and plastic side of the internal heating unit has a conveying spiral, the heat exchange area is large, and the higher temperature is conducive to strengthening heat transfer. At the same time, the flue gas after heat exchange enters the external heating unit, so that the outer wall temperature of the external heating unit is low, and the heat dissipation loss is small.

[0042] In this embodiment, the flow direction of the high-temperature flue gas is opposite to the movement direction of the waste rubber and plastic. The temperature at the inlet of the waste rubber and plastic is low, and the temperature at the outlet 8 of the pyrolysis carbon black is high. In the initial stage of pyrolysis of the waste rubber and plastic, more pyrolysis gas is precipitated. The lower temperature can avoid the degree of pyrolysis gas cracking and improve the oil yield. When the pyrolysis is basically completed, the higher temperature can ensure the complete pyrolysis of the waste rubber and plastic. On the other hand, the higher the temperature, the lower the ability of the pyrolysis carbon black to adsorb the pyrolysis gas, which can reduce the oil content of the pyrolysis carbon black. The quality of the hot gas product is greatly improved.

[0043] In the sealing unit of this embodiment, the front pyrolysis gas sealing component 901 adopts a graphite packing sealing structure, and the rear pyrolysis gas sealing component and the flue gas sealing component adopt a double sealing structure of graphite packing combined with nitrogen sealing.

[0044] The temperature of the post-pyrolysis gas sealing component and the flue gas sealing component is high, and the sealing requirements are high. The double sealing structure of graphite packing combined with nitrogen sealing consists of graphite packing, nitrogen inlet pipe and nitrogen chamber. The nitrogen flow is monitored to determine whether the sealing structure is intact. During the operation of the pyrolysis device, the nitrogen pressure is kept constant. If the nitrogen flow rate rises suddenly or increases significantly compared to the initial flow rate, it means that the seal is damaged, otherwise the seal is intact.

[0045] In this embodiment, a plurality of temperature measuring points, pressure measuring points and flow measuring points are arranged on the pyrolysis cylinder to monitor and control the pyrolysis temperature, the pyrolysis chamber pressure and the nitrogen flow rate, so as to accurately control the temperature of the pyrolysis system and monitor the operating status of the pyrolysis device.

Claims

1. A high-efficiency pyrolysis device for waste rubber and plastic with heat transfer enhancement coupled with grinding function, comprising a support and a pyrolysis cylinder arranged on the support, characterized in that: The pyrolysis cylinder is provided with: A pyrolysis chamber is arranged along the axial direction of the pyrolysis cylinder, and a screw is installed in the pyrolysis chamber. The central axis of the screw is a hollow shaft. The central axis is divided into a same diameter section and a reduced diameter section from the feed inlet, and the central axis diameter of the reduced diameter section gradually increases; a reverse spiral is arranged at the end of the screw of the reduced diameter section, and the reverse spiral is located at the rear of the pyrolysis carbon black outlet and consists of 3 to 4 teeth; Feeding unit, used for feeding waste rubber and plastic; An internal heating unit, which heats from the cavity of the central axis of the screw; An external heating unit is used to heat the outer side of the screw; Pyrolysis gas outlet, used to discharge pyrolysis gas of waste rubber and plastic; A pyrolytic carbon black outlet is used to discharge the pyrolytic carbon black; The central axis is provided with a double-layer cavity, and the internal heating unit includes a smoke inlet and a smoke outlet arranged at the same end of the central axis, the smoke inlet is connected to the outer cavity of the central axis, and the smoke outlet is connected to the inner cavity of the central axis; the inner cavity is connected to the outer cavity at the other end; the outer cavity is provided with heat transfer fins; the high-temperature smoke first enters the internal heating unit, is discharged after heat exchange, and then enters the external heating unit; the flow direction of the high-temperature smoke is opposite to the movement direction of the waste rubber and plastic; The length ratio of the same diameter section and the reduced diameter section of the screw is 1:1; the height of the spiral teeth at the end of the reduced diameter section is half of the height of the spiral teeth in the same diameter section; the same diameter section means that the diameter of the central axis of the screw in this section remains unchanged, while the reduced diameter section means that the diameter of the central axis of the screw gradually increases and the corresponding tooth height decreases; during the pyrolysis process, the waste rubber and plastic particles are first pyrolyzed by heat on the outside, expand after being heated, and become denser under the rotation and extrusion of the spiral, which is conducive to the conduction of heat; while the spiral rotates, the waste rubber and plastic particles are subjected to the circumferential shear force, the particles rub against each other and mix, and the pyrolyzed part of the outer layer is easy to peel off, which is conducive to the pyrolysis of the inside of the waste rubber and plastic particles; The pyrolysis cylinder is also provided with a sealing unit, which includes a front pyrolysis gas sealing assembly arranged at the feed end of the pyrolysis cylinder, a rear pyrolysis gas sealing assembly arranged at the outlet end of the pyrolysis cylinder, and a flue gas sealing assembly; the front pyrolysis gas sealing assembly adopts a graphite packing sealing structure; the rear pyrolysis gas sealing assembly and the flue gas sealing assembly adopt a double sealing structure of graphite packing combined with nitrogen sealing, including graphite packing, a nitrogen inlet pipe and a nitrogen chamber, and the nitrogen flow is monitored to determine whether the sealing structure is intact; during the operation of the pyrolysis device, the nitrogen pressure is kept unchanged. If the nitrogen flow rate suddenly rises or increases significantly compared to the initial flow rate, it means that the seal is damaged, otherwise the seal is intact.

2. The high-efficiency pyrolysis device for waste rubber and plastic with heat transfer enhancement coupled with grinding function according to claim 1 is characterized in that: The external heating unit comprises a heating cylinder arranged outside the pyrolysis cylinder, a smoke passage is formed between the heating cylinder and the pyrolysis cylinder, a smoke inlet is provided at one end of the heating cylinder, and a smoke outlet is provided at the other end.

3. The high-efficiency pyrolysis device for waste rubber and plastic with heat transfer enhancement coupled with grinding function according to claim 1 is characterized in that: The pyrolysis cylinder is provided with a plurality of temperature measuring points, pressure measuring points and flow measuring points for monitoring and controlling the pyrolysis temperature, the pyrolysis chamber pressure and the nitrogen flow.

4. The high-efficiency pyrolysis device for waste rubber and plastic with heat transfer enhancement coupled with grinding function according to claim 1 is characterized in that: The feeding unit comprises a hopper and a feeding screw vertically arranged in the hopper, a plug valve is arranged at the bottom of the hopper, and the feeding screw is driven by a variable frequency motor to feed.

5. The high-efficiency pyrolysis device for waste rubber and plastic with heat transfer enhancement coupled with grinding function according to claim 1 is characterized in that: The support is provided with a power unit for driving the screw to rotate, and the power unit includes a variable frequency motor, a reducer, a coupling and a thrust bearing, and also includes a supporting wheel arranged at the other end of the pyrolysis cylinder.

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