Flue gas circulation double-heating waste tire plastic cracking furnace device and heating method thereof

Abstract

The invention discloses a flue gas circulation double-heating waste tire plastic cracking furnace device. Comprising a furnace body provided with a rotary inner barrel, a smoke collecting barrel arranged on the upper portion of the furnace body and communicated with a rotary barrel heating chamber between the rotary inner barrel and the furnace body, a circulating smoke heating chamber arranged on the lower portion of the furnace body and communicated with the rotary barrel heating chamber, and feeding devices arranged on the furnace body on the two sides of the furnace body and communicated with an inner cavity of the rotary barrel. A radiant tube capable of heating and cracking waste materials in the rotary inner cylinder is arranged in the rotary inner cylinder in the inner cavity of the furnace body, and a main burner communicated with an external fuel gas source is arranged in the inner cavity of the circulating flue gas heating chamber; and a flue gas circulating pipeline communicated with a circulating flue gas inlet in the chamber wall of the other side of the circulating flue gas heating chamber is connected with a circulating flue gas outlet of a flue gas collecting cylinder arranged at the upper part of the furnace body, so that a high-temperature heating system for internal and external circulation of high-temperature flue gas is formed.

Description

Technical Field

[0001] This invention relates to a flue gas recirculation dual-heating waste tire plastic pyrolysis furnace device and its heating method, belonging to the field of heating technology for environmental solid waste treatment and reuse. Background Technology

[0002] Rotary pyrolysis furnaces are important equipment for the treatment of solid waste materials such as waste tires and waste plastics. Their main function is to pyrolyze organic waste materials such as waste tires and waste plastics by heating them, and convert them into usable oil products and carbon black.

[0003] The commonly used rotary pyrolysis furnace, as shown in the attached image... Figure 7 and attached Figure 8 The two types shown: (The rest is missing from the original text.) Figure 7 A pyrolysis furnace for intermittent production; attached Figure 8 It is a pyrolysis furnace for continuous production.

[0004] like Figure 7 , 8 Both of the pyrolysis furnaces shown include a feeding device 16, a slag discharge auger 1, a furnace body 4 fixed on a base, a rotating inner cylinder 7 located inside the furnace body 4, and a heating chamber 46 located at the lower part of the furnace body 4 and inserted into the lower opening of the furnace body to form a heating chamber 46 for external heating of the rotating inner cylinder 7.

[0005] The principles of these two rotary pyrolysis furnaces for pyrolyzing waste tires and plastics are as follows: one, Figure 7 The intermittent pyrolysis furnace shown uses an auger to feed waste tires and waste plastics to be pyrolyzed from one end of the furnace into the rotating inner cylinder 7 inside the outer furnace body 4. After the rotating inner cylinder 7 is filled with the materials to be pyrolyzed, the furnace door is closed, and the rotating inner cylinder 7 is heated by the heating chamber 46 located at the bottom of the furnace body. As the rotating inner cylinder 7 inside the furnace body 4 rotates, the materials entering the rotating inner cylinder 7 are heated and pyrolyzed. Solid waste materials such as waste tires and waste plastics are tumbled inside the rotating inner cylinder 7 furnace chamber while undergoing pyrolysis under the heat provided by the heating chamber 46 located below the rotating inner cylinder 7. The rotation of the rotating inner cylinder 7 within the furnace body 4 ensures the temperature uniformity of the materials inside the furnace. The oil and gas and carbon black produced by heating and decomposition are discharged as gasified products from the flue gas rising channel 13 and flue gas collecting cylinder 11 located at the top of the furnace body 4, and the residue is discharged from the slag discharge auger 1 located on the other side of the furnace body. The drawback of this intermittent pyrolysis furnace is that it can only process waste tires and waste plastic solid waste materials one furnace at a time; obviously, the utilization rate of the above device is very limited.

[0006] two, Figure 8 What is shown is the Figure 7Further improvements to the intermittent pyrolysis furnace shown enable it to continuously feed and heat solid waste materials such as waste tires and waste plastics into the rotating inner cylinder 7, and continuously discharge the processed waste residue, thus achieving continuous waste residue treatment. The improvement measures are as follows: material guide plates 25 are arranged in a ring on the inner wall of the rotating inner cylinder 7, so that the waste materials to be pyrolyzed entering the inner cavity of the rotating inner cylinder 7 can not only tumble in the rotating inner cylinder 7 as the rotating inner cylinder 7 rotates, but also automatically move the materials in the cylinder from the feed port end of the cylinder to the slag discharge auger 1 located on the other side of the cylinder, thereby achieving continuous treatment of waste tires and waste plastic solid waste materials.

[0007] Because the waste material inside the rotating inner cylinder 7 undergoes pyrolysis and produces oil and gas under low-temperature, oxygen-deficient conditions (400-550℃), the heat transfer process is primarily convective, with minimal radiative heat transfer. Therefore, increasing the convective heat transfer within this rotating system is crucial for improving system temperature uniformity and heating rate. Two main measures to increase convective heat transfer are: firstly, increasing the flue gas velocity; and secondly, increasing the flue gas flow rate.

[0008] However, existing ones such as Figure 7 , Figure 8 The two types of pyrolysis furnaces described above produce relatively little flue gas, resulting in poor uniformity of flue gas distribution within the effective heating zone of the rotating inner cylinder 7. This leads to uneven temperature distribution of the material inside the furnace, affecting the pyrolysis oil yield. Increasing the amount of combustion air to increase the amount of flue gas inside the rotating inner cylinder would increase the amount of emitted flue gas, reducing the furnace's thermal efficiency. Furthermore, organic waste has poor thermal conductivity and is loosely packed, causing the temperature in the central region of the rotating inner cylinder 7 to be significantly lower than the temperature at the edges of the furnace. This directly impacts the pyrolysis process, resulting in lower furnace capacity and heating times exceeding 2.5 hours.

[0009] Therefore, improving the oil production rate of the pyrolysis furnace, shortening the waste pyrolysis cycle, and increasing the furnace's capacity are important tasks in waste pyrolysis.

[0010] Currently, there is no low-cost heating and separation method or equipment that can significantly improve the temperature uniformity inside the cracking furnace, increase oil production and furnace capacity, while also reducing fuel consumption and improving the thermal properties inside the furnace. Summary of the Invention

[0011] The purpose of this invention is to propose a waste tire plastic pyrolysis furnace device and its heating method with flue gas circulation and dual heating. By adopting a combined heating method of high-temperature flue gas circulation and central dual heating, the device can improve the temperature uniformity of materials in the pyrolysis furnace, increase the production efficiency of the pyrolysis furnace, reduce NOx emissions, solve the current problems encountered by organic waste pyrolysis furnaces, and achieve the positive effect of effectively reducing fuel consumption and increasing the oil yield of pyrolysis products.

[0012] The above-mentioned objective is achieved through the following technical solution: This flue gas circulating dual-heating waste tire plastic pyrolysis furnace device includes a furnace body 4 with a rotating inner cylinder 7 in its inner cavity; a flue gas collecting cylinder 11 located on the upper part of the furnace body and communicating with the rotating inner cylinder 7 and the furnace body 4 through a rotating cylinder heating chamber 44; a circulating flue gas heating chamber 33 located on the lower part of the furnace body and communicating with the rotating inner cylinder 7 and the furnace body 4 through a rotating inner cylinder heating chamber 44; a feeding device, a slag discharge device, and an oil and gas emission outlet 2 respectively located on the left and right sides of the furnace body 4 and communicating with the inner cavity of the rotating inner cylinder 7. Its characteristic is that: The inner cylinder 7 of the furnace body 4 is equipped with a radiant tube 24 that can directly heat and crack the waste entering the inner cylinder 7. The inner cavity of the circulating flue gas heating chamber 33 is equipped with a main burner 31 that is connected to an external gas source. The circulating flue gas heating chamber 33 is connected to the circulating flue gas outlet 8 of the flue gas collecting cylinder 11 at the top of the furnace body through the circulating flue gas inlet 36 on the other side wall of the circulating flue gas heating chamber 33 and the flue gas circulation pipe 3 connected to the circulating flue gas inlet 36. This constitutes a high-temperature heating system with internal and external circulation of high-temperature flue gas.

[0013] Furthermore, the main burner 31 is installed on the side wall of the circulating flue gas heating chamber 33. The main burner 31 is connected to the combustion fan 28 via an external pipe equipped with an air regulating valve 30 to obtain combustion air. At the same time, the main burner 31 is connected to two gas pipelines, an external natural gas pipeline 26 and a cracked non-condensable gas pipeline 27, to obtain the gas used by the main burner.

[0014] Furthermore, the radiant tube 24 is horizontally arranged in an "I" shape in the central area of ​​the rotating inner cylinder 7. Its tube body has a double-layer structure. One end of the radiant tube 24 is supported by the inner wall of one side of the furnace body 4, and the other end is fixed to the inner wall of the other end of the furnace body 4 through the front radiant support arm 24.2. The radiant tube guide tube 24.1 located in the inner layer of the radiant tube 24 is connected to the rear self-preheating radiant tube burner 22. A radiant tube guard plate 21 embedded in the inner cavity of the radiant guide tube is provided above the radiant tube 24 on the side of the self-preheating radiant tube burner 22. A radiant tube temperature control thermocouple 23 that can control the surface temperature of the radiant tube according to the pyrolysis process requirements is provided below the radiant tube 24. A flue gas emission interface, a combustion air inlet, and a gas inlet are provided on the outer nozzle of the self-preheating radiant tube burner 22.

[0015] Furthermore, the furnace body 4 has a flue gas equalization plate 34 at the opening of its contact surface with the circulating flue gas heating chamber 33 located at the bottom. This plate covers the upper part of the circulating flue gas heating chamber 33 and has several flue gas equalization holes 34.1 on its surface. At the same time, there are two side-by-side isolation plates 35 in the inner cavity of the circulating flue gas heating chamber 33. These plates are perpendicular to the bottom of the circulating flue gas heating chamber 33, abut against the flue gas equalization plate 34 at the top, and have several high-temperature flue gas inlets 35.1 on their surfaces. This forms a circulation space for the hot flue gas, and the flue gas equalization holes 34.1 on the flue gas equalization plate 34 located at the top of the isolation plate 35 form a conveying channel for the hot gas in the entire circulating flue gas chamber 33 to the rotary cylinder heating chamber 44.

[0016] Furthermore, the inner wall of the rotating inner cylinder 7 is provided with a material guide plate 25 that can rotate with the rotating inner cylinder 7 and move the material inside the cylinder from the feed end to the slag discharge auger 1. A rotating cylinder roller ring 43 is provided at each end of the outer cylinder surface of the rotating inner cylinder 7, and a rotating cylinder gear 14 is provided on the outer cylinder surface at the feed end of the rotating inner cylinder 7. The rotating cylinder gear 14 meshes with the rotating cylinder rotating device 29 located at the lower part of the feed end of the rotating inner cylinder 7 to form the driving structure of the rotating cylinder gear 14. The rotating cylinder roller ring 43 is supported on the rotating cylinder support wheel 39.

[0017] Furthermore, a flue gas collecting cylinder 11 is provided above the furnace body 4, and the flue gas circulation pipe 3 is connected to the flue gas collecting cylinder 11 through the circulating flue gas outlet 8. A circulating fan 40 is provided on the flue gas circulation pipe 3, and a circulating flue gas regulating valve 37 is provided on the outlet pipe of the circulating fan 40 and is connected to the circulating flue gas inlet 36 provided on the circulating flue gas heating chamber 33.

[0018] Furthermore, the feeding device consists of a waste conveying device 16 and a feeding basket 15, a feeding sealing chamber 17, and a guide trough 19 connected in sequence. An upper sealing slide plate 18 and a lower sealing slide plate 20 are respectively provided at the joints between the feeding basket 15 and the feeding sealing chamber 17, and between the feeding sealing chamber 17 and the guide trough 19. The outlet of the guide trough 19 is directly connected to the inner cavity of the rotating inner cylinder 7.

[0019] Furthermore, the lower left and right sides of the rotating inner cylinder 7 are provided with rotating support wheels 39 and rotating cylinder rotating device 29, and the rotating cylinder rotating device 29 and the rotating cylinder rotating gear 32 provided on the rotating inner cylinder 7 constitute the driving mechanism of the rotating inner cylinder 7.

[0020] Furthermore, a rotary cylinder sealing device 5 is provided in the cavity between the two ends of the rotary inner cylinder 7 and the furnace body 4. In the cavities between the rotary inner cylinder 7 and the furnace body 4 located between the left and right rotary cylinder sealing devices 5 and near the rotary inner cylinder 7 and the circulating flue gas heating chamber 33, a high-temperature flue gas sealing device 6 is provided on the left and right, thereby forming the rotary outer heating chamber 44 of the rotary inner cylinder 7.

[0021] Furthermore, the slag discharge device is located on the lower side of the furnace body 4 on the other side corresponding to the feeding device. The slag discharge device consists of a waste slag sealing chamber 42 and a waste slag outlet 41 that are connected to the inner cavity of the rotating inner cylinder 7. A slag discharge sealing device 38 is provided at the junction of the waste slag sealing chamber 42 and the waste slag outlet 41. At the same time, a slag discharge auger 1 and an oil and gas discharge outlet 2 are provided on the furnace body side above the waste slag sealing chamber 42 and the waste slag outlet 41.

[0022] This flue gas recirculation dual-heating waste tire plastic pyrolysis furnace device uses the following method for pyrolyzing waste tire plastics: 1) Loading Organic waste is conveyed from the waste conveying device 16 to the feed basket 15. After the waste reaches the set weight, the upper sealing slide plate 18 in the waste conveying device 16 opens, and the waste enters the feed sealing chamber 17. As the upper sealing slide plate 18 closes, the lower sealing slide plate 20 opens, and the waste enters the rotating inner cylinder 7 through the guide chute 19, completing one loading cycle before being heated and cracked. At the same time, the system enters preparation for another feeding process, forming continuous production. 2) Pyrolysis As the rotating inner cylinder 7 rotates, the material guide plate 25 installed on the inner wall of the rotating inner cylinder 7 transports the material entering the inner cavity of the rotating inner cylinder 7 towards the outlet end of the rotating inner cylinder 7. During the process of transporting the material in the inner cavity of the rotating inner cylinder 7, the material inside the cylinder is heated and cracked by the hot flue gas ejected from the radiant tube 24 installed in the inner cavity of the rotating inner cylinder 7. At the same time, it is also heated and cracked by the hot flue gas generated from the circulating flue gas heating chamber 33 and enters the rotating cavity between the furnace body 4 and the rotating inner cylinder 7 through the flue gas equalization holes 34.1 on the flue gas equalization plate 34. The inner cylinder heating chamber 44 heats and pyrolyzes the waste material passing through the inner cavity of the rotating inner cylinder 7 from outside the rotating inner cylinder heating chamber 44; the flue gas after heating is entered into the flue gas collecting cylinder 11 through the flue gas rising channel 13 set at the upper part of the furnace body 4, and is sent back to the self-circulating flue gas heating chamber 3 through the circulating flue gas outlet 8 to enter the next external circulation heating and pyrolysis process; at the same time, the oil and gas mixture generated by pyrolysis in the inner cavity of the rotating inner cylinder 7 is sent to the oil and gas recovery condenser from the oil and gas discharge outlet 2 set on the other side of the furnace body 4. 3) Treatment of residues after pyrolysis After the pyrolysis is completed, the waste residue enters the waste residue sealing chamber 42. After the waste residue accumulates to a certain amount, the slag discharge sealing device 38 is opened, allowing the waste residue to be discharged from the waste residue outlet through the waste residue sealing chamber 42. If the waste residue is difficult to discharge, the slag discharge auger 1 is started to send the waste residue out of the rotating inner cylinder 7. The waste residue is then transported to the outlet end of the rotating inner cylinder 1 by the material guide plate 25 set in the inner cavity of the rotating inner cylinder 7 and enters the waste residue sealing chamber 42. After the waste residue accumulates to a certain amount, the slag discharge sealing device 38 is opened to discharge the waste residue.

[0023] The flue gas recirculation dual-heating waste tire plastic pyrolysis furnace device and its heating method proposed in the above technical solution have the following advantages: 1) The circulating high-temperature flue gas, after being heated by the burners, is evenly distributed to both sides of the rotary kiln body. Due to the significant increase in flue gas volume and rapid circulation, the flue gas velocity is increased by 3 to 4 times compared to existing equipment. Consequently, the heat transfer coefficient between the flue gas and the rotary kiln body increases by 3 to 4 times, significantly improving heating efficiency. A large volume of flue gas fills the heating chamber, and the flue gas temperature is precisely controllable, ensuring uniform heating of the rotary kiln body, avoiding localized high-temperature zones, and improving the oil yield during the pyrolysis process.

[0024] 2) The radiant tube heating set in the center of the furnace makes the material temperature more uniform, increases the heating speed, and improves the thermal efficiency, which increases the oil production rate of the cracking process and also improves the capacity of the cracking furnace.

[0025] 3) The material inlet and outlet processes are completely sealed, ensuring a good pyrolysis environment and realizing a green pyrolysis process.

[0026] 4) The use of dual heating for pyrolysis shortens the pyrolysis cycle and improves the efficiency of the pyrolysis furnace. With the same production capacity, it has played a role in reducing the initial investment in equipment. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the structure and working principle of a radiant tube; Figure 3 for Figure 1 Sectional view along axis AA; Figure 4 for Figure 1 BB view; Figure 5 A top view of a waste tire plastic pyrolysis furnace device with flue gas circulation and dual heating; Figure 6 For the flue gas recirculation dual-heating waste tire plastic pyrolysis furnace device, the flue gas recirculation single... Side-heated BB side view.

[0028] Figure 7 This is the currently used intermittent production cracking furnace; Figure 8 This is the pyrolysis furnace currently in use for continuous production.

[0029] In the picture: 1-Slag discharge auger; 2-Oil and gas emission outlet; 3-Flue gas circulation pipe; 4-Furnace body; 5-Rotating inner cylinder sealing device; 6-High temperature flue gas sealing device; 7-Rotating inner cylinder; 8-Circulating flue gas outlet; 9-Flue gas emission regulating valve; 10-Flue gas emission port; 11-Flue gas collecting cylinder; 12-Flue gas pressure sensor; 13-Flue gas rising channel; 15-Feed basket; 16-Waste conveying device; 17-Feed sealing chamber; 18-Upper sealing slide plate; 19-Guide chute; 20 - Lower sealing slide plate; 21 - Radiation pipe protective plate; 21.1 - Radiation tube protective plate support plate; 22 - Radiation tube burner; 23-Radiation control thermocouple; 24-Radiation tube; 24.1-Radiation tube guide tube; 24.2-Radiation tube support arm; 25-Material guide plate; 26-Natural gas pipeline; 27-Cracked non-condensable gas pipeline; 28-Combustion fan; 29-Rotating inner cylinder rotating device; 30-Air regulating valve; 31-Main burner; 32-Rotating inner cylinder rotating gear; 33- Circulating flue gas heating chamber; 34- Flue gas flow equalization plate; 34.1- Flue gas flow equalization hole; 35- High-temperature flue gas inlet; 36- Circulating flue gas inlet; 37-Circulating flue gas regulating valve; 38-Slag discharge sealing device; 39 - Rotary inner cylinder support wheel; 40 - Circulating fan; 41 - Waste outlet; 42-Waste residue sealing chamber; 43-Rotating inner cylinder roller ring; 44 - Rotary inner cylinder heating chamber; 45 - Flue gas thermocouple; 46 - Heating chamber. Detailed Implementation

[0030] The core innovation of this invention, which proposes a flue gas recirculation dual-heating waste tire plastic pyrolysis furnace, lies in the following four points: 1. The flue gas generated during the operation of the heating pyrolysis furnace is recirculated and reheated before being fed back into the furnace. Without changing the air-fuel ratio in the combustion process, the amount of flue gas in the furnace is greatly increased. Under the action of the circulating fan, the flue gas running speed is increased, the heat transfer coefficient between the flue gas and the rotary kiln is greatly increased, the pyrolysis conditions of the materials in the furnace are improved, and the oil production rate during the pyrolysis process is increased.

[0031] 2. The temperature of the reheated circulating flue gas can be precisely controlled, avoiding premature carbonization of materials due to local overheating of the pyrolysis furnace, which would affect the oil production rate.

[0032] 3. The furnace center uses radiant tube heating, which greatly improves the uniformity of material pyrolysis temperature, increases the pyrolysis rate, maximizes heating efficiency, reduces pyrolysis energy consumption, increases furnace capacity, and reduces equipment investment.

[0033] 4. The feeding and discharging device adopts a sealed chamber structure, which ensures a good working environment during the continuous pyrolysis process and realizes truly green pyrolysis production.

[0034] The present invention will be further described below with reference to the accompanying drawings, and embodiments of the present invention will be given.

[0035] Appendix Figure 1 The diagram provided is a schematic representation of the overall structure of the waste tire plastic pyrolysis furnace device with flue gas circulation and dual heating proposed in this invention.

[0036] This flue gas circulating dual-heating waste tire plastic pyrolysis furnace device includes a furnace body 4 with a rotating inner cylinder 7 in its inner cavity; a flue gas collecting cylinder 11 located on the upper part of the furnace body and communicating with the rotating inner cylinder 7 and the furnace body 4 through a rotating cylinder heating chamber 44; a circulating flue gas heating chamber 33 located on the lower part of the furnace body and communicating with the rotating inner cylinder 7 and the furnace body 4 through a rotating inner cylinder heating chamber 44; a feeding device, a slag discharge device, and an oil and gas discharge outlet 2 respectively located on the left and right sides of the furnace body 4 and communicating with the inner cavity of the rotating inner cylinder 7. The inner cylinder 7 of the 4th cavity is equipped with a radiant tube 24 that can directly heat and crack the waste entering the inner cylinder 7. The inner cavity of the circulating flue gas heating chamber 33 is equipped with a main burner 31 that is connected to the external gas source. The circulating flue gas heating chamber 33 is connected to the circulating flue gas outlet 8 of the flue gas collection cylinder 11 located at the top of the furnace body through the circulating flue gas inlet 36 set on the other side wall of the circulating flue gas heating chamber 33 and the flue gas circulation pipe 3 connected to the circulating flue gas inlet 36. Thus, a high-temperature heating system with internal and external circulation of high-temperature flue gas is formed.

[0037] The main burner 31 is installed on the side wall of the circulating flue gas heating chamber 33. The main burner 31 is connected to the combustion fan 28 via an external pipe equipped with an air regulating valve 30 to obtain combustion air. At the same time, the main burner 31 is connected to two gas pipelines, namely the external natural gas pipeline 26 and the cracked non-condensable gas pipeline 27, to obtain the gas used by the main burner.

[0038] Because a circulating fan 40 circulates most of the flue gas discharged outside the furnace to the lower heating zone of the furnace, it is reheated before entering the furnace. The "I-type" radiant tube 24 located in the center of the furnace uses a self-preheating burner to heat and control the temperature of the radiant tube. This ensures that the material to be cracked in the rotating inner cylinder 7 receives dual heating from both inside and outside, resulting in more uniform temperature and faster cracking speed.

[0039] Appendix Figure 2 This is a schematic diagram of the structure of the radiant tube 24.

[0040] The radiant tube 24 shown in the figure is horizontally arranged in an "I" shape in the central area of ​​the rotating inner cylinder 7. Its tube body has a double-layer structure. One end of the radiant tube 24 is supported by one side wall of the furnace body 4, and the other end is fixed to the inner side wall of the other end of the furnace body 4 through the front radiant support arm 24.2. The radiant tube guide tube 24.1 located in the inner layer of the radiant tube 24 is connected to the rear self-preheating radiant tube burner 22. A radiant tube guard plate 21 embedded in the inner cavity of the radiant guide tube is provided above the radiant tube 24 on the side of the self-preheating radiant tube burner 22. A radiant temperature control thermocouple 23 is provided below the radiant tube 24 to control the surface temperature of the radiant tube 24 according to the pyrolysis process requirements. A flue gas emission interface, a combustion air inlet, and a gas inlet are provided on the outer nozzle of the self-preheating radiant tube burner 22.

[0041] In actual use, the high-temperature flue gas generated by the self-preheating radiant tube burner 22 located at the rear is transported forward through the radiant tube guide tube 24.1 located in the inner layer of the radiant tube 24, and at the same time, the heat energy is conducted to the entire radiant tube 24 body through the channel between the inner radiant tube guide tube and the outer shell of the radiant tube 24, directly heating and cracking the waste material in the rotating inner cylinder 7.

[0042] Appendix Figure 3 This is a front view (AA) of the waste tire plastic pyrolysis furnace device with dual heating and flue gas circulation. The lower part consists of two heating zones on both sides. The high-temperature flue gas after heating is evenly distributed from the middle area to the inner cylinder heating chambers 44 on both sides of the rotating inner cylinder 7, heating the cylinder from the outside and thus heating the waste material entering the rotating inner cylinder 7.

[0043] Appendix Figure 4 This is a BB view of the flue gas recirculation dual-heating waste tire plastic pyrolysis furnace unit. It shows the external shape of the pyrolysis furnace at the discharge end.

[0044] Figure 5 This is a BB view of a waste tire plastic pyrolysis furnace device with flue gas circulation and dual heating, showing a single-sided heating flue gas circulation. It is an example of a single-sided heating flue gas circulation system.

[0045] This waste tire plastic pyrolysis furnace device with dual heating and flue gas circulation consists of: 1. Slag discharge auger; 2. Oil and gas emission outlet; 3. Flue gas circulation pipe; 4. Furnace body; 5. Rotary inner cylinder sealing device; 6. High-temperature flue gas sealing device; 7. Rotary inner cylinder; 8. Circulating flue gas outlet; 9. Flue gas emission regulating valve; 10. Flue gas emission port; 11. Flue gas collecting cylinder; 12. Flue gas pressure sensor; 13. Flue gas rising channel; 14. Rotary inner cylinder gear; 15. Feed basket; 16. Waste material conveying device; 17. Upper sealing slide plate; 18. Feed sealing chamber; 19. Lower sealing slide plate; 20. Guide chute; 21. Radiant tube protective plate; 22. Radiant tube burner; and radiant control system. The system consists of a thermocouple 23, a radiant tube 24, a material guide plate 25, a rotating gear for the inner cylinder 26, a rotating device for the inner cylinder 27, a natural gas pipeline 28, a cracked non-condensable gas pipeline 29, a combustion fan 30, an air regulating valve 31, a main burner 32, a circulating flue gas heating chamber 33, a flue gas equalization plate 34, a high-temperature flue gas inlet 35, a circulating flue gas inlet 36, a circulating flue gas regulating valve 37, a slag discharge sealing device 38, a rotating inner cylinder support wheel 39, a circulating fan 40, a waste slag outlet 41, a waste slag sealing chamber 42, a rotating inner cylinder roller ring 43, a rotating inner cylinder heating chamber 44, and a flue gas thermocouple 45.

[0046] Its specific structure is as follows: A flue gas collecting cylinder 11 is installed above the furnace body 4. The flue gas circulation pipe 3 is connected to the flue gas collecting cylinder 11 through the circulating flue gas outlet 8. A circulating fan 40 is installed on the flue gas circulation pipe 3. A circulating flue gas regulating valve 37 is installed on the outlet pipe of the circulating fan 40 and is connected to the circulating flue gas inlet 36. Part of the flue gas in the flue gas collecting cylinder 11 is transported by the circulating fan 40 to the circulating flue gas heating chamber 33 through the flue gas circulation pipe 3. In the circulating flue gas heating chamber 33, it is heated to the set temperature by the main burner 32. The high-temperature flue gas enters the rotating inner cylinder heating chamber 44 through the high-temperature flue gas inlet 35 and the flue gas equalization plate 34. Because the flue gas circulation greatly increases the amount of high-temperature flue gas heating the rotating inner cylinder 7, it increases the flow rate of the flue gas heating process, that is, it increases the convective heat transfer between the flue gas and the rotary furnace, and enables the system to accurately control the flue gas temperature, completely eliminating the local high-temperature zone in the heating process, and realizing uniform and rapid heating of the rotating inner cylinder 7. Simultaneously, an "I-type" radiant tube 24 equipped with a radiant tube burner 22, located at the center of the rotating inner cylinder 7, heats the material in the central region of the furnace. This achieves waste pyrolysis through high-temperature flue gas circulation and dual heating in the central region, resulting in a more uniform pyrolysis process at a more uniform temperature. This improves the oil yield, shortens the pyrolysis time, increases the furnace's capacity, reduces energy consumption, and decreases NOx generation.

[0047] The flue gas circulation duct 3 is connected to the flue gas collecting cylinder 11 located above the furnace body 4 via the circulating flue gas outlet 8. A portion of the flue gas in the collecting cylinder 11 (approximately two-thirds or more) is transported to the circulating flue gas heating chamber 33 via the circulating fan 40. The outlet duct of the circulating fan 40 is equipped with a circulating flue gas regulating valve 37 and a main burner 31 to regulate the flue gas circulation volume. After the high-temperature circulating flue gas is heated by the main burner 31, the temperature of the mixed flue gas is monitored by the flue gas thermocouple 45. By adjusting the flue gas circulation volume and the power of the main burner 31, the flue gas temperature is controlled at a set value before entering the rotating inner cylinder heating chamber 44.

[0048] The main burner 31 is mounted on the side wall of the circulating flue gas heating chamber 33. Combustion air for the main burner 31 is supplied by a combustion fan 28. A circulating flue gas regulating valve 37 is installed on the air duct to regulate the amount of air entering the main burner 31, ensuring an accurate air-fuel ratio. The main burner 31 has two gas pipelines: a natural gas pipeline 26 and a cracked non-condensable gas pipeline 27. Initially, the system uses natural gas as the heat source. Once cracking begins, the system switches to burning cracked non-condensable gas, or both fuels can burn simultaneously.

[0049] The "Type I" radiant tube 24 is located in the central area of ​​the furnace, with one end supported by the side wall of the furnace body 4 and the other end fixed to the other side wall of the furnace body 4, and equipped with a radiant tube burner 22, which is a self-preheating burner. It can use natural gas and cracked uncondensed gas as fuel. A radiant tube guard plate 21 is installed above the radiant tube 24 on the side of the burner 22 to protect the radiant tube 24 from damage by waste entering the furnace. A radiant tube temperature control thermocouple 23 is installed below the radiant tube 24 to control the surface temperature of the radiant tube according to the requirements of the cracking process.

[0050] The feeding device consists of a waste conveying device 16, a feeding basket 15, an upper sealing slide plate 18, a feeding sealing chamber 17, a lower sealing slide plate 20, and a guide chute 19. Organic waste is conveyed to the feeding basket 15 by the waste conveying device 16. After the waste reaches the set weight, the upper sealing slide plate 18 opens, and the waste enters the feeding sealing chamber 17. The upper sealing slide plate 18 closes, the lower sealing slide plate 20 opens, and the waste enters the rotating inner cylinder 7 through the guide chute 19, where it is heated and cracked.

[0051] The inner wall of the rotating inner cylinder 7 is equipped with a material guide plate 25, which moves the material from the feed end to the slag discharge auger 1 as the rotating inner cylinder 7 rotates. Rotating inner cylinder roller rings 42 are installed at both ends of the outer wall of the rotating inner cylinder 7, and a rotating inner cylinder gear 14 is installed at the feed end of the rotating inner cylinder 7. The rotating inner cylinder roller rings 43 are supported on rotating inner cylinder support wheels 39. The rotating inner cylinder 7 is driven by the rotating inner cylinder rotation device 29 through the rotating inner cylinder rotation gear 32 to rotate the rotating inner cylinder gear 14. Rotating inner cylinder sealing devices 5 are installed at both ends of the rotating inner cylinder 7 and the furnace body 4 to ensure that the rotating inner cylinder 7 is sealed to the furnace body 4 during rotation. High-temperature flue gas sealing devices 6 are also installed at both ends of the rotating inner cylinder heating chamber 44 to reduce the damage of high-temperature flue gas to the rotating inner cylinder sealing devices 5.

[0052] The circulating flue gas heating chamber 33 has a circulating flue gas inlet 36 at one end and a main burner 31 for heating at the other end. The chamber is divided into three areas: the two outer areas are flue gas heating zones, and the middle area is a flue gas mixing zone. Alternatively, the circulating flue gas heating chamber 33 can be divided into two areas: one side is the flue gas heating zone, and the other side is the flue gas mixing zone. A high-temperature flue gas inlet 35 is provided inside the circulating flue gas heating chamber 33, allowing the heated high-temperature flue gas to enter the circulating flue gas heating chamber 33 evenly. The flue gas then passes through a flue gas equalization plate 34 located at the top of the circulating flue gas heating chamber 33. This flue gas equalization plate 34 has flue gas equalization holes 34.1 on its surface, thus forming a conveying channel from the circulating flue gas heating chamber 34 to the rotating inner cylinder heating chamber 44 between the rotating inner cylinder 7 and the furnace body 4. Simultaneously, the rotating inner cylinder heating chamber 44 allows the high-temperature flue gas to enter the rotating inner cylinder 7 evenly from both sides, uniformly and rapidly heating the rotating inner cylinder 7. This makes the rotating inner cylinder heating chamber 44 a carrier capable of heating and pyrolyzing materials passing through the inner cavity of the rotating inner cylinder 7 from the outside.

[0053] The flue gas collecting cylinder 11 is positioned above the furnace body 4 and is connected to the rotating inner cylinder heating chamber 44 via the flue gas rising channel 13. High-temperature flue gas from the rotating inner cylinder heating chamber 44 enters the flue gas collecting cylinder 11 through the flue gas rising channel 13. The flue gas collecting cylinder 11 has two flue gas outlets: a circulating flue gas outlet 8 and a flue gas discharge port 10. A small portion of the flue gas is discharged through the flue gas discharge port 10, while most of the flue gas is circulated back to the circulating flue gas heating chamber 33 via the circulating flue gas outlet 8. A flue gas discharge regulating valve 9 is installed in the flue gas discharge pipe, and a flue gas pressure sensor 12 is installed on the flue gas collecting cylinder 11. The flue gas discharge regulating valve 9 is adjusted by the flue gas pressure sensor 12 to ensure a slightly positive pressure state inside the furnace.

[0054] The waste residue outlet 41 consists of a waste residue sealing chamber 42 and a waste residue discharge sealing device 38. The pyrolysis waste residue is conveyed by the material guide plate 25 to the outlet end of the rotating inner cylinder 7, enters the waste residue sealing chamber 42, and after a certain amount of waste residue accumulates, the waste residue discharge sealing device 38 is opened to discharge the waste residue. If waste residue discharge is difficult, the waste residue discharge auger 1 is activated to send the waste residue out of the inner cavity of the rotating inner cylinder 7.

[0055] The furnace body 4 is equipped with a heat insulation layer. The feed end is equipped with a feed chute 19, a radiant tube burner 22, a radiant tube 24, and a radiant temperature control thermocouple 23. The discharge end is equipped with a waste residue outlet 41 and an oil and gas emission outlet 2. The cracked oil and gas are transported from the oil and gas emission outlet 2 to subsequent condensation treatment equipment for oil and gas recovery.

[0056] The heating method of the pyrolysis furnace device with high-temperature flue gas circulation and central dual heating is as follows: Most of the flue gas discharged into the flue gas collection cylinder 11 is transported to the circulating flue gas heating chamber 33 by the circulating fan 40 through the flue gas circulation pipe 3. After being reheated by the main burner 31, it is evenly fed back into the rotating inner cylinder 7, which is close to the rotating cylinder heating chamber 44, through the flue gas equalization plate 34. The temperature of the reheated circulating flue gas is monitored by the flue gas thermocouple 45 and is interlocked with the circulating flue gas regulating valve 37 on the flue gas circulation pipe 3, so that the temperature of the reheated circulating flue gas is maintained at the set value.

[0057] The "I-type" radiant tube 24, located at the center of the rotating inner cylinder 7, is equipped with a radiant tube burner 22. This burner is a self-preheating burner. The radiant tube 24 is equipped with a radiant temperature control thermocouple 23, which is interlocked with the radiant tube burner 22 to control the surface temperature of the radiant tube 24 to be maintained at the set value.

[0058] The material operation method of the aforementioned flue gas circulating dual-heating waste tire plastic pyrolysis furnace is as follows: Organic waste is conveyed to the feed basket 15 by the waste conveying device 16. After the waste reaches the set weight, the upper sealing slide plate 17 opens, and the waste enters the feed sealing chamber 18. The upper sealing slide plate 17 closes, and the lower sealing slide plate 19 opens, allowing the waste to enter the rotating inner cylinder 7 via the guide chute 20, where it is heated and pyrolyzed. One feeding cycle is completed, and the system enters another feeding process, forming continuous production. As the rotating inner cylinder 7 rotates, the material guide plate 25 inside it conveys the material to the outlet end of the rotating inner cylinder 7. The pyrolyzed waste residue enters the waste residue sealing chamber 42. After a certain amount of waste residue accumulates, the slag discharge sealing device 38 is opened to discharge the waste residue. If there is difficulty in discharging the waste residue, the slag discharge auger 1 is activated to send the waste residue out of the rotating inner cylinder 7. The pyrolyzed waste residue is conveyed to the outlet end of the rotating inner cylinder 7 by the material guide plate 25, enters the waste residue sealing chamber 42, and after a certain amount of waste residue accumulates, the slag discharge sealing device 38 is opened to discharge the waste residue. If there is difficulty in discharging the waste residue, the slag discharge screw conveyor 1 is activated to send the waste residue out of the rotating inner cylinder 7. The pyrolysis furnace is a continuous production equipment.

[0059] During the pyrolysis process, most of the flue gas discharged from the furnace is transported to the lower part of the furnace by a circulating fan, where it is reheated by burners before entering the furnace. This eliminates the process of coking and carbon black formation caused by localized high temperatures in the material during pyrolysis. Radiant tubes located in the center of the furnace heat the core of the material inside, ensuring that the material pyrolyzes under uniform temperature conditions. This improves the oil yield from pyrolysis, increases the equipment's capacity, and reduces pyrolysis costs. During continuous production, material feeding and discharging occur under sealed conditions, achieving environmentally friendly green production.

[0060] The above is merely the basic implementation of the present invention provided by the applicant based on the technical solution. Any improvements made by those skilled in the art without substantial creativity based on the technical solution should be considered to fall within the protection scope of the present invention.

Claims

1. A flue gas circulating dual-heating waste tire plastic pyrolysis furnace device, comprising a furnace body (4) with a rotating inner cylinder (7) in its inner cavity, a flue gas collecting cylinder (11) located on the upper part of the furnace body and communicating with the rotating inner cylinder (7) and the furnace body (4) through a rotating cylinder heating chamber (44), a circulating flue gas heating chamber (33) located on the lower part of the furnace body and communicating with the rotating inner cylinder (7) and the furnace body (4) through a rotating cylinder heating chamber (44), a feeding device, a slag discharge device, and an oil and gas discharge outlet (2) respectively located on the left and right sides of the furnace body (4) and communicating with the inner cavity of the rotating inner cylinder (7), characterized in that: The inner cavity of the furnace body (4) is provided with a radiant tube (24) that can directly heat and crack the waste entering the inner cavity of the rotating inner cylinder (7). The inner cavity of the circulating flue gas heating chamber (33) is provided with a main burner (31) that is connected to the external gas source. The circulating flue gas heating chamber (33) is connected to the circulating flue gas outlet (8) of the flue gas collection cylinder (11) located at the top of the furnace body through the circulating flue gas inlet (36) provided on the other side wall of the circulating flue gas heating chamber (33) and the flue gas circulation pipe (3) connected to the circulating flue gas inlet (36). Thus, a high-temperature heating system with internal and external circulation of high-temperature flue gas is formed.

2. The flue gas circulating dual-heating waste tire plastic pyrolysis furnace device as described in claim 1, characterized in that: The main burner (31) is installed on the side wall of the circulating flue gas heating chamber (33). The main burner (31) is connected to the combustion fan (28) via an external pipe equipped with an air regulating valve (30) to obtain combustion air. At the same time, the main burner (31) is connected to the gas used by the main burner via two gas pipelines: an external natural gas pipeline (26) and a cracked non-condensable gas pipeline (27).

3. The flue gas circulating dual-heating waste tire plastic pyrolysis furnace device as described in claim 1, characterized in that: The radiation tube (24) is horizontally arranged in an "I" shape in the center area of ​​the rotating inner cylinder (7). Its tube body has a double-layer structure. One end of the radiation tube (24) is supported by the inner wall of the furnace body (4), and the other end is fixed to the inner wall of the other end of the furnace body (4) through the front radiation support arm (24.2). The radiation tube guide tube (24.1) located in the inner layer of the radiation tube (24) is connected to the self-preheating radiation tube burner (22) at the rear. A radiation tube guard plate (21) embedded in the inner cavity of the radiation guide tube is provided above the radiation tube (24) on the side of the self-preheating radiation tube burner (22). A radiation control temperature thermocouple (23) that can control the surface temperature of the radiation tube according to the requirements of the pyrolysis process is provided below the radiation tube (24). A flue gas emission interface, a combustion air inlet and a gas inlet are provided on the outer nozzle of the self-preheating radiation tube burner (22).

4. The waste tire plastic pyrolysis furnace device with flue gas circulation and dual heating as described in claim 1, characterized in that: The furnace body (4) has a flue gas equalization plate (34) covering the upper part of the circulating flue gas heating chamber (33) and having several flue gas equalization holes (34.1) on its surface. At the same time, two isolation plates (35) are arranged side by side perpendicular to the bottom of the circulating flue gas heating chamber (33), with their upper parts abutting against the flue gas equalization plate (34) and having several high-temperature flue gas inlets (35.1) on their surfaces. This forms a limited space for the hot flue gas. The flue gas equalization holes (34.1) on the upper part of the isolation plate (35) form a conveying channel for the hot airflow in the entire circulating flue gas chamber (33) to the rotary cylinder heating chamber (44).

5. The flue gas circulating dual-heating waste tire plastic pyrolysis furnace device as described in claim 1, characterized in that: The inner wall of the rotating inner cylinder (7) is provided with a material guide plate (25) that can rotate with the rotating cylinder (7) and move the material in the cylinder from the feed end to the slag discharge auger (1). A rotating cylinder roller ring (43) is provided at each end of the outer cylinder surface of the rotating inner cylinder (7), and a rotating cylinder gear (14) is provided on the outer cylinder surface at the feed end of the rotating inner cylinder (7). The rotating cylinder gear (14) meshes with the rotating cylinder rotating device (29) located at the lower part of the feed end of the rotating inner cylinder (7) to form the driving structure of the rotating cylinder gear (14). The rotating cylinder roller ring (43) is supported on the rotating cylinder support wheel (39).

6. The waste tire plastic pyrolysis furnace device with flue gas circulation and dual heating as described in claim 1, characterized in that: A flue gas collection cylinder (11) is provided above the furnace body (4). The flue gas circulation pipe (3) is connected to the flue gas collection cylinder (11) through the circulating flue gas outlet (8). A circulating fan (40) is provided on the flue gas circulation pipe (3). A circulating flue gas regulating valve (37) is provided on the outlet pipe of the circulating fan (40) and is connected to the circulating flue gas inlet (36) provided on the circulating flue gas heating chamber (33).

7. The flue gas circulating dual-heating waste tire plastic pyrolysis furnace device as described in claim 1, characterized in that: The feeding device consists of a waste conveying device (16) and a feeding basket (15), a feeding sealing chamber (17), and a guide trough (19) connected in sequence. An upper sealing slide plate (18) and a lower sealing slide plate (20) are respectively provided at the joints of the feeding basket (15) and the feeding sealing chamber (17), and the feeding sealing chamber (17) and the guide trough (19). The outlet of the guide trough (19) is directly connected to the inner cavity of the rotating inner cylinder (7).

8. The flue gas circulating dual-heating waste tire plastic pyrolysis furnace device as described in claim 1, characterized in that: The lower left and right sides of the rotating inner cylinder (7) are provided with rotating support wheels (39) and rotating cylinder rotating device (29). The rotating cylinder rotating device (29) and the rotating cylinder rotating gear (32) provided on the rotating inner cylinder (7) constitute the driving mechanism of the rotating inner cylinder (7).

9. The flue gas circulating dual-heating waste tire plastic pyrolysis furnace device as described in claim 1, characterized in that: A rotary cylinder sealing device (5) is provided in the cavity between the two ends of the rotary inner cylinder (7) and the furnace body (4). A high-temperature flue gas sealing device (6) is provided in the two cavities between the rotary inner cylinder (7) and the furnace body (4) located between the left and right rotary cylinder sealing devices (5) and the two cavities close to the rotary inner cylinder (7) and the circulating flue gas heating chamber (33). This constitutes the external heating chamber (44) of the rotary inner cylinder (7).

10. The flue gas circulating dual-heating waste tire plastic pyrolysis furnace device as described in claim 1, characterized in that: The slag discharge device is located on the lower side of the furnace body (4) on the other side corresponding to the feeding device. The slag discharge device consists of a slag sealing chamber (42) and a slag outlet (41) that are connected to the inner cavity of the rotating inner cylinder (7). A slag discharge sealing device (38) is provided at the junction of the slag sealing chamber (42) and the slag outlet (41). At the same time, a slag discharge auger (1) and an oil and gas discharge outlet (2) are provided on the side of the furnace body above the slag sealing chamber (42) and the slag outlet (41).

11. The waste tire plastic pyrolysis furnace device with flue gas circulation and dual heating as described in claim 1, wherein the pyrolysis method for waste tire plastic is as follows: 1) Loading Organic waste is transported to the feed basket (15) by the waste conveying device (16). After the waste reaches the set weight, the upper sealing slide plate (18) in the waste conveying device (16) opens, and the waste enters the feed sealing chamber (17). As the upper sealing slide plate (18) closes, the lower sealing slide plate (20) opens, and the waste enters the rotating inner cylinder (7) through the guide chute (19), completing one loading cycle before being heated and cracked. At the same time, the system enters the preparation for another feeding process, forming continuous production. 2) Pyrolysis As the rotating inner cylinder (7) rotates, the waste material entering the inner cavity of the rotating inner cylinder (7) is transported to the outlet end of the rotating inner cylinder (7) by the material guide plate (25) set on the inner wall of the rotating inner cylinder (7). During the transportation process in the inner cavity of the rotating inner cylinder (7), the waste material is heated and cracked by the radiation tube (24) set in the inner cavity of the rotating inner cylinder (7) while being heated and cracked by the radiation tube (24) set in the inner cavity of the rotating inner cylinder (7). At the same time, the heated flue gas generated in the self-circulating flue gas heating chamber (33) enters the rotating cylinder heating chamber (44) between the furnace body (4) and the rotating inner cylinder (7) through the high temperature flue gas inlet (35.1) on the isolation plate (35) set in the circulating flue gas heating chamber (33) and the flue gas equalization hole (34.1) on the flue gas equalization plate (34) set at the junction with the furnace body (4). The waste material entering the inner cavity of the rotating inner cylinder (7) is transported from the outside of the rotating inner cylinder (7) to the rotating inner cylinder (7) by the material guide plate (25) set in the inner cavity of the rotating inner cylinder (7). The hot flue gas ejected from the radiant tube (24) is heated and cracked. At the same time, the heated flue gas generated from the circulating flue gas heating chamber (33) enters the rotating cylinder heating chamber (44) between the furnace body (4) and the rotating inner cylinder (7) through the flue gas equalization hole (34.1). The waste passing through the inner cavity of the rotating inner cylinder (7) is heated and cracked from the outside of the rotating inner cylinder (7). The heated flue gas enters the flue gas collecting cylinder (11) through the flue gas rising channel (13) set at the top of the furnace body (4), and is sent back to the flue gas circulation pipe (3) through the circulating flue gas outlet (8) to enter the self-circulating flue gas heating chamber (33) to enter the next external circulation heating and cracking process. At the same time, the oil and gas mixture generated by cracking in the inner cavity of the rotating inner cylinder (7) is sent to the oil and gas recovery condenser from the oil and gas discharge outlet 2 on the other side of the furnace body (4). 3) Treatment of residues after pyrolysis After the pyrolysis is completed, the waste residue enters the waste residue sealing chamber (42). After the waste residue accumulates to a certain amount, the slag discharge sealing device (38) is opened, allowing the waste residue to be discharged from the waste residue outlet through the waste residue sealing chamber (42). If the waste residue is difficult to discharge, the slag discharge auger (1) is started to send the waste residue out of the rotating inner cylinder (7). The waste residue is then transported to the outlet end of the rotating inner cylinder (1) through the material guide plate (25) set in the inner cavity of the rotating inner cylinder (7) and enters the waste residue sealing chamber (42). After the waste residue accumulates to a certain amount, the slag discharge sealing device (38) is opened to discharge the waste residue.

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