Anti-coking waste plastic rotary kiln pyrolysis device
By employing a grinding mechanism with metal steel balls and a spiral guide plate, along with a waste heat recovery system in the rotary kiln pyrolysis unit, the coking problem in the plastic pyrolysis process was solved, improving pyrolysis efficiency and energy utilization efficiency, and achieving product quality stability and energy consumption reduction.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- CHONGQING UNIVERSITY OF SCIENCE AND TECHNOLOGY
- Filing Date
- 2025-07-29
- Publication Date
- 2026-07-21
AI Technical Summary
Existing rotary kiln pyrolysis devices are prone to coking during plastic pyrolysis, resulting in low heat transfer efficiency, equipment blockage, low pyrolysis efficiency, unstable product quality, and insufficient utilization of the thermal energy of high-temperature flue gas and solid residue, leading to high system energy consumption.
The grinding mechanism, which combines metal steel balls and spiral guide plates, with an annular heating chamber and waste heat recovery system, prevents coking through mechanical grinding in the rotating drum and utilizes high-temperature flue gas and ash for energy cascade utilization, integrating separation and combustion systems.
It has achieved the prevention of coking, improved pyrolysis efficiency and product quality stability, reduced system energy consumption, and realized the efficient utilization of thermal energy from flue gas and solid residue.
Smart Images
Figure CN224530862U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of waste recycling and treatment technology, specifically, it relates to a waste plastic rotary kiln pyrolysis device that prevents coking. Background Technology
[0002] With the large-scale use of plastic products, the recycling and disposal of waste plastics has become a global environmental issue. Traditional waste plastic treatment methods mainly include landfill, incineration, and physical recycling, but these methods have drawbacks such as secondary pollution, resource waste, or low processing efficiency. Pyrolysis technology, as an emerging method for the resource utilization of waste plastics, can convert waste plastics into valuable products such as fuel oil, gas, and solid charcoal, exhibiting good environmental protection and economic benefits.
[0003] Rotary kiln pyrolysis equipment is one of the most widely used waste plastic pyrolysis devices, which decomposes plastics through a high-temperature oxygen-free or low-oxygen environment.
[0004] In the existing technology, plastics are prone to coking on the inner wall of the rotary kiln during the pyrolysis process, which affects the heat transfer efficiency and may cause equipment blockage, requiring frequent shutdowns for cleaning. Traditional rotary kilns rely on external heating, resulting in uneven heating of plastics, low pyrolysis efficiency, unstable product quality, and the thermal energy of the high-temperature flue gas and solid residue generated during the pyrolysis process is not fully utilized, resulting in high system energy consumption.
[0005] To address the aforementioned problems, this application proposes a waste plastic rotary kiln pyrolysis device that prevents coking. Utility Model Content
[0006] In response to the problems in related technologies, this utility model proposes a waste plastic rotary kiln pyrolysis device to prevent coking, thereby overcoming the aforementioned technical problems existing in the existing related technologies.
[0007] To achieve the above objectives, the present invention adopts the following technical solution:
[0008] A waste plastic rotary kiln pyrolysis device for preventing coking includes an outer shell, a rotating cylinder rotatably connected to the inner side of the outer shell, an annular heating chamber formed on the inner side of the outer shell, the annular heating chamber cooperating with the rotating cylinder, a first cyclone separator installed on the left side of the outer shell, a feeding hopper fixedly installed on the right side of the outer shell, a distillation device installed on the top of the first cyclone separator, a coke tank installed at the bottom of the first cyclone separator, a combustion chamber connected to one side of the coke tank, a riser pipe installed at the top of the combustion chamber, a second cyclone separator installed at the top of the riser pipe, an exhaust pipe installed at the top of the second cyclone separator, a discharge pipe installed at the bottom of the second cyclone separator, and the discharge pipe cooperating with the feeding hopper.
[0009] The grinding mechanism includes multiple metal steel balls, which are arranged inside a rotating cylinder. A screen is provided at the connection between the left side of the outer shell and the first cyclone separator. The screen and the metal steel balls cooperate with each other.
[0010] The waste heat recovery mechanism includes a heat exchanger installed on one side of the combustion chamber and connected to the combustion chamber, with a blower installed on top of the heat exchanger.
[0011] Preferably, the grinding mechanism further includes a spiral guide plate, which cooperates with multiple metal steel balls.
[0012] The rotating spiral guide plate facilitates the flow of metal steel balls, allowing them to rotate and roll on the inner wall of the rotating cylinder, grinding the internal plastic and removing slag from the inner wall of the rotating cylinder.
[0013] Preferably, guide pipes are installed on both sides of the outer shell. The guide pipe on the right side is fixedly connected to the feeding hopper, and the two guide pipes are separated at their closest ends. A rotating shaft is rotatably connected inside the guide pipe, and an auger is fixedly installed on the rotating shaft. A second motor is fixedly installed on both sides of the outer shell, and the output shaft of the second motor is fixedly connected to the corresponding rotating shaft. An opening is opened at the top of the guide pipe on the left side, and a scraper is fixedly installed on the inner wall of one side of the rotating cylinder. The scraper and the opening cooperate with each other.
[0014] The rotating drum pushes the metal steel balls upwards through the scraper, and they fall into the inside of the guide pipe through the opening. The output shafts of the two second motors drive the two rotating shafts to rotate, and the rotating shafts drive the auger to rotate. The auger on the right side guides the material on the hopper, while the auger on the left side can convey the metal steel balls, so that the metal steel balls move back to the right side and are reintroduced into the rotating drum through the partition space between the two guide pipes, thus facilitating the re-grinding operation.
[0015] Preferably, one side of the rotating cylinder extends through the right side of the outer casing, and a first motor is fixedly installed on the right side of the outer casing. A drive gear is fixedly installed on the output shaft of the first motor, and a driven gear is fixedly installed at one end of the rotating cylinder. The drive gear and the driven gear mesh with each other.
[0016] The output shaft of the first motor drives the rotating drum to rotate through the meshing of the drive gear and the driven gear, thereby uniformly heating the plastic inside the rotating drum.
[0017] Preferably, the waste heat recovery mechanism further includes a return gas pipe, which is installed at the bottom of the outer shell and one end of the return gas pipe is connected to the heat exchanger. An outlet pipe is installed on one side of the heat exchanger, and a spiral heat exchange tube is installed on the inner wall of the heat exchanger. The two ends of the spiral heat exchange tube are connected to the blower and the combustion chamber, respectively.
[0018] By setting up a return gas pipe, the flue gas flowing back into the outer shell can be discharged. Through the setting of the heat exchanger, the heat inside the flue gas can be exchanged under the action of the spiral heat exchange tube, and the incoming air can be preheated.
[0019] Preferably, an induced draft fan is installed at the top of the distillation unit, and a connecting pipe is connected to the top of the induced draft fan, which is connected to a coke tank.
[0020] By installing an induced draft fan, the flue gas generated during the pyrolysis of plastics in the rotating drum can be drawn in, and the oil and gas in the flue gas can be condensed by a distillation device, thereby achieving separation and purification.
[0021] In summary, the technical effects and advantages of this utility model are as follows:
[0022] 1. Dynamic grinding and self-cleaning system
[0023] Metal steel balls working in conjunction with a spiral guide plate: Multiple metal steel balls installed inside the rotating cylinder work together with a spiral guide plate to mechanically grind the plastic during rotation, accelerating the pyrolysis reaction. At the same time, the metal steel balls can effectively scrape the inner wall of the rotating cylinder, preventing coking and deposition.
[0024] By setting up two augers and a guide pipe, the feeding effect of the hopper can be increased, and the metal steel balls can be automatically circulated and guided, so that the metal steel balls can always move and grind within the rotating drum.
[0025] Screen isolation design: A screen is installed at the outlet of the rotating drum to prevent steel balls from entering the subsequent separation system and ensure the safe operation of the equipment.
[0026] 2. High-efficiency pyrolysis and energy cascade utilization
[0027] Indirect heating via annular heating chamber: The high-temperature flue gas after combustion is uniformly heated by the rotating cylinder through the annular heating chamber, avoiding local overheating or coking caused by direct contact.
[0028] Multi-stage waste heat recovery:
[0029] High-temperature flue gas is preheated by a heat exchanger to improve combustion efficiency;
[0030] After the flue gas releases heat, it is reheated in the rotating cylinder and then returned to the heat exchanger through the return gas pipe, thus realizing the cascade utilization of energy.
[0031] 3. Integrated separation and combustion system
[0032] Cyclone separation-distillation-combustion coupling:
[0033] The first cyclone separator quickly separates pyrolysis gas from carbon slag, the distillation unit condenses and recovers the oil and gas, and the non-condensable gas and carbon slag enter the combustion chamber for complete combustion, reducing pollution emissions.
[0034] The combustion chamber is combined with the riser to ensure complete combustion of carbon slag, and the high-temperature ash slag re-enters the rotary kiln to participate in pyrolysis, forming a material cycle.
[0035] The second cyclone separator separates ash and slag: the high-temperature ash and slag after combustion are separated from the flue gas, and the ash and slag are recycled to the rotating drum, and the waste heat of the flue gas is further utilized.
[0036] This invention employs a method of simultaneous internal and external heating (external flue gas, internal high-temperature ash). Since high-temperature ash particles are easily reduced in heat exchange area when encased in plastic, steel balls are used to enhance heat exchange. In addition, the steel balls can also break up char during operation. Furthermore, this patent uses a steel ball recycling and return device to realize the reciprocating motion of the steel balls inside. Attached Figure Description
[0037] Figure 1 This is a schematic diagram of the overall structure of this utility model;
[0038] Figure 2 This is a schematic diagram of the rear view structure of this utility model;
[0039] Figure 3 This is a schematic diagram of the internal structure of the outer shell of this utility model;
[0040] Figure 4 This is a cross-sectional view of the outer shell and rotating cylinder of this utility model.
[0041] In the picture:
[0042] 1. Outer shell; 2. First cyclone separator; 3. Coke tank; 4. Distillation unit; 5. Exhaust fan; 6. Feed hopper; 7. Rotary cylinder; 8. Annular heating chamber; 9. First motor; 10. Drive gear; 11. Driven gear; 12. Second motor; 13. Rotating shaft; 14. Spiral guide plate; 15. Metal steel ball; 16. Screen; 17. Feed pipe; 18. Scraper; 19. Opening; 21. Combustion chamber; 22. Riser pipe; 23. Second cyclone separator; 24. Heat exchanger; 25. Blower; 26. Screwdriver. Detailed Implementation
[0043] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.
[0044] Reference Figure 1-4A waste plastic rotary kiln pyrolysis device for preventing coking includes an outer shell 1, a rotating cylinder 7 rotatably connected to the inner side of the outer shell 1, an annular heating chamber 8 opened on the inner side of the outer shell 1, the annular heating chamber 8 and the rotating cylinder 7 cooperating with each other, a first cyclone separator 2 installed on the left side of the outer shell 1, a feeding hopper 6 fixedly installed on the right side of the outer shell 1, a distillation device 4 installed on the top of the first cyclone separator 2, a coke tank 3 installed at the bottom of the first cyclone separator 2, a combustion chamber 21 connected to one side of the coke tank 3, a riser pipe 22 installed at the top of the combustion chamber 21, a second cyclone separator 23 installed at the top of the riser pipe 22, an exhaust pipe installed at the top of the second cyclone separator 23, a discharge pipe installed at the bottom of the second cyclone separator 23, and the discharge pipe cooperating with the feeding hopper 6.
[0045] The grinding mechanism includes multiple metal steel balls 15, which are arranged inside the rotating cylinder 7. A screen 16 is provided at the connection between the left side of the outer shell 1 and the first cyclone separator 2. The screen 16 and the metal steel balls 15 cooperate with each other.
[0046] The waste heat recovery mechanism includes a heat exchanger 24, which is installed on one side of the combustion chamber 21 and is connected to the combustion chamber 21. A blower 25 is installed on the top of the heat exchanger 24.
[0047] Reference Figure 1 and Figure 4 The grinding mechanism also includes a spiral guide plate 14, which cooperates with multiple metal steel balls 15. Guide pipes 17 are installed on both sides of the outer casing 1. The right guide pipe 17 is fixedly connected to the feeding hopper 6, and the two guide pipes 17 are separated at their closest ends. A rotating shaft 13 is rotatably connected inside the guide pipe 17, and an auger 26 is fixedly installed on the rotating shaft 13. A second motor 12 is fixedly installed on both sides of the outer casing 1, and the output shaft of the second motor 12 is fixedly connected to the corresponding rotating shaft 13. An opening 19 is provided at the top of the left guide pipe 17. A scraper 18 is fixedly installed on the inner wall of one side of the rotating cylinder 7, and the scraper 18 cooperates with the opening 19. The rotating spiral guide plate 14 facilitates the grinding of the metal steel balls 15. The flow guide allows the metal steel balls 15 to rotate and roll on the inner wall of the rotating cylinder 7, grinding the internal plastic and removing slag from the inner wall of the rotating cylinder 7. The rotating cylinder 7 pushes the metal steel balls 15 upward through the scraper 18 and drops them into the inner side of the guide pipe 17 through the opening 19. The output shafts of the two second motors 12 drive the two rotating shafts 13 to rotate, and the rotating shafts 13 drive the auger 26 to rotate. The right rotating auger 26 guides the material on the feed hopper 6, while the left auger 26 can convey the metal steel balls 15, causing them to move back to the right end and be reintroduced into the rotating cylinder 7 through the partition space between the two guide pipes 17, thus facilitating the re-grinding operation.
[0048] Reference Figure 4 One side of the rotating cylinder 7 extends through the right side of the outer shell 1, and the right side of the outer shell 1 is fixedly installed with a first motor 9. A drive gear 10 is fixedly installed on the output shaft of the first motor 9, and a driven gear 11 is fixedly installed at one end of the rotating cylinder 7. The drive gear 10 and the driven gear 11 mesh with each other. The output shaft of the first motor 9 can drive the rotating cylinder 7 to rotate through the meshing of the drive gear 10 and the driven gear 11, thereby uniformly heating the plastic inside the rotating cylinder 7.
[0049] Reference Figure 2 The waste heat recovery mechanism also includes a return gas pipe, which is installed at the bottom of the outer shell 1 and one end of the return gas pipe is connected to the heat exchanger 24. An outlet pipe is installed on one side of the heat exchanger 24, and a spiral heat exchange tube is installed on the inner wall of the heat exchanger 24. The two ends of the spiral heat exchange tube are connected to the blower and the combustion chamber 21, respectively. Through the setting of the return gas pipe, the flue gas flowing back into the outer shell 1 can be discharged. Through the setting of the heat exchanger 24, under the action of the spiral heat exchange tube, the heat in the flue gas can be exchanged and the incoming air can be preheated.
[0050] Reference Figure 2 The top of the distillation unit 4 is equipped with an induced draft fan 5, and the top of the induced draft fan 5 is connected to a connecting pipe, which is connected to the coke tank 3. By setting the induced draft fan 5, the flue gas generated during the pyrolysis of plastic in the rotating cylinder 7 can be drawn in, and the oil and gas in the flue gas can be condensed by the distillation unit 4, thereby achieving separation and purification.
[0051] Working principle: Plastic enters the rotating drum 7 through the feeding hopper 6 and guide pipe 17 on one side of the outer shell 1. Metal steel balls 15 are laid inside the rotating drum 7. As the rotating drum 7 rotates, the metal steel balls 15 move from the right side to the left side under the action of the spiral guide plate 14. When the metal steel balls 15 reach the left side of the rotating drum 7, the rotating drum 7 pushes the metal steel balls 15 upwards through the scraper 18, and they fall into the inside of the guide pipe 17 through the opening 19. The output shafts of the two second motors 12 drive two rotating... Shaft 13 rotates, driving auger 26 to rotate. The right-side rotating auger 26 guides the material from the hopper 6, while the left-side auger 26 conveys the steel balls 15, causing them to move back to the right end and be reintroduced into the rotating drum 7 through the partition space between the two guide pipes 17. This facilitates re-grinding. The screen 16 prevents the steel balls 15 from entering the rear end. The oil-gas mixture and carbon residue generated by the plastic pyrolysis reaction enter the first cyclone separator under the action of the subsequent induced draft fan 5. Separator 2: Carbon slag enters coke tank 3, oil-gas mixture enters distillation unit 4, non-condensable gas enters coke tank 3 after passing through distillation unit 4, and is sent into subsequent riser 22 along with carbon slag. Gas in riser 22 enters combustion chamber 21, while blower 25 sends air into combustion chamber 21 through heat exchanger 24, where it reacts with non-condensable gas. The high-temperature flue gas and ash produced by combustion are separated by second cyclone separator 23. High-temperature ash and plastic enter rotating cylinder 7 through outer shell 1, while high-temperature flue gas enters cyclone separator 7. Inside the annular heating chamber 8 outside the rotating drum 7, the rotating drum 7 is heated. The flue gas after releasing heat is introduced into the heat exchanger 24 through the return gas pipe. The incoming air is heated by the spiral heat exchange tube. The flue gas after releasing heat enters the subsequent flue gas treatment system. The air after absorbing heat enters the riser pipe 22 through the combustion chamber 21 to provide the air required for the combustion of carbon slag and non-condensable gases. At the same time, the output shaft of the first motor 9 drives the rotating drum 7 to rotate through the meshing of the drive gear 10 and the driven gear 11, thereby uniformly heating the plastic inside the rotating drum 7.
[0052] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.
Claims
1. A waste plastic rotary kiln pyrolysis device for preventing coking, comprising an outer shell (1), characterized in that, A rotating cylinder (7) is rotatably connected to the inner side of the outer shell (1). An annular heating chamber (8) is opened on the inner side of the outer shell (1). The annular heating chamber (8) and the rotating cylinder (7) cooperate with each other. A first cyclone separator (2) is installed on the left side of the outer shell (1). A feeding hopper (6) is fixedly installed on the right side of the outer shell (1). A distillation device (4) is installed on the top of the first cyclone separator (2). A coke tank (3) is installed at the bottom of the first cyclone separator (2). A combustion chamber (21) is connected to one side of the coke tank (3). A riser pipe (22) is installed at the top of the combustion chamber (21). A second cyclone separator (23) is installed at the top of the riser pipe (22). An exhaust pipe is installed at the top of the second cyclone separator (23). A discharge pipe is installed at the bottom of the second cyclone separator (23). The discharge pipe cooperates with the feeding hopper (6). The grinding mechanism includes multiple metal steel balls (15), which are arranged inside the rotating cylinder (7). A screen (16) is provided at the connection between the left side of the outer shell (1) and the first cyclone separator (2). The screen (16) and the metal steel balls (15) cooperate with each other. The waste heat recovery mechanism includes a heat exchanger (24), which is installed on one side of the combustion chamber (21) and is connected to the combustion chamber (21). A blower (25) is installed on the top of the heat exchanger (24).
2. The anti-coking waste plastic rotary kiln pyrolysis device according to claim 1, characterized in that, The grinding mechanism also includes a spiral guide plate (14), which cooperates with a plurality of metal steel balls (15).
3. The anti-coking waste plastic rotary kiln pyrolysis device according to claim 1, characterized in that, The outer shell (1) is equipped with guide pipes (17) on both sides. The guide pipe (17) on the right side is fixedly connected to the feeding hopper (6), and the two guide pipes (17) are separated at their close ends. A rotating shaft (13) is rotatably connected inside the guide pipe (17). An auger (26) is fixedly installed on the rotating shaft (13). A second motor (12) is fixedly installed on both sides of the outer shell (1). The output shaft of the second motor (12) is fixedly connected to the corresponding rotating shaft (13). An opening (19) is opened at the top of the guide pipe (17) on the left side. A scraper (18) is fixedly installed on the inner wall of one side of the rotating cylinder (7). The scraper (18) and the opening (19) cooperate with each other.
4. The anti-coking waste plastic rotary kiln pyrolysis device according to claim 1, characterized in that, One side of the rotating cylinder (7) extends through the right side of the outer shell (1), and a first motor (9) is fixedly installed on the right side of the outer shell (1). A drive gear (10) is fixedly installed on the output shaft of the first motor (9), and a driven gear (11) is fixedly installed at one end of the rotating cylinder (7). The drive gear (10) and the driven gear (11) mesh with each other.
5. The anti-coking waste plastic rotary kiln pyrolysis device according to claim 1, characterized in that, The waste heat recovery mechanism also includes a return gas pipe, which is installed at the bottom of the outer shell (1) and one end of the return gas pipe is connected to the heat exchanger (24). An outlet pipe is installed on one side of the heat exchanger (24), and a spiral heat exchange tube is installed on the inner wall of the heat exchanger (24). The two ends of the spiral heat exchange tube are connected to the blower (25) and the combustion chamber (21) respectively.
6. The anti-coking waste plastic rotary kiln pyrolysis device according to claim 1, characterized in that, The distillation unit (4) is equipped with an induced draft fan (5) at the top, and the top of the induced draft fan (5) is connected to a connecting pipe, which is connected to the coke tank (3).