Low-rank coal powder low-temperature pyrolysis system

Abstract

The present application relates to the technical fields of coal clean utilization, more particularly, to a low-rank coal powder low-temperature pyrolysis system, comprising a pyrolysis furnace, a coal powder drying device connected to the feeding end of the pyrolysis furnace, a gas treatment device and a solid collection vehicle connected to the discharging end of the pyrolysis furnace; the coal powder drying device comprises a drying base and a drying cylinder rotatably arranged on the drying base; the pyrolysis furnace comprises a furnace body and a heating device, the heating device comprises a heating jacket fixedly arranged on the outside of the furnace body, two partition plates are arranged between the heating jacket and the furnace body, and the two partition plates divide the heating jacket into three buffer spaces; the side wall of the furnace body is uniformly provided with a plurality of hot air inlets in the axial direction and in communication with the buffer spaces, and each buffer space is connected with a hot carrier gas pipeline. The oil gas waste heat generated in the gas treatment device is recovered through a heat exchanger and an insulation pipeline as a heat source for drying the coal powder, thereby effectively reducing the overall external energy consumption of the system and realizing internal step-by-step utilization of energy.

Description

Technical Field

[0001] This invention relates to the field of clean coal utilization technology, and more specifically, to a low-temperature pyrolysis system for low-rank coal powder. Background Technology

[0002] Low-rank coal (such as lignite and long-flame coal) is abundant, but its inherent high moisture content, high volatile matter content, and low calorific value limit its direct utilization efficiency. Low-temperature pyrolysis technology is one of the effective ways to improve the quality of low-rank coal. By pyrolyzing pulverized coal under medium-low temperature conditions (approximately 500-650℃), upgraded coal (semi-coke), coal tar, and pyrolysis gas can be obtained simultaneously. Upgraded coal has advantages such as low moisture and volatile matter content, high calorific value, and good hydrophobicity; coal tar and pyrolysis gas can be used as high-value chemical raw materials or fuels.

[0003] However, existing low-temperature pyrolysis systems for low-rank coal powder still face numerous technical bottlenecks. First, the high moisture content of coal powder significantly increases energy consumption during pyrolysis and affects the quality and yield of the pyrolysis products. Traditional pre-drying devices often suffer from low thermal efficiency and uneven drying, leading to energy losses. Second, the pyrolysis of coal powder within the pyrolysis furnace is a complex dynamic process, sequentially undergoing preheating and drying, primary distillation, and upgrading and solidification stages, each with different temperature and time requirements. Existing pyrolysis furnaces often employ single-temperature zone or simple temperature gradient control, making it difficult to precisely and independently regulate each of these stages, resulting in incomplete pyrolysis of coal powder, low tar yield, or unstable solid product quality.

[0004] Therefore, it is necessary to improve existing technologies. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, a low-temperature pyrolysis system for low-rank coal powder is provided, which features efficient drying, precise segmented pyrolysis, and stable transportation.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A low-temperature pyrolysis system for low-rank coal powder includes a pyrolysis furnace, with a coal powder drying device connected to the feed end of the pyrolysis furnace and a gas processing device and a solid collection vehicle connected to the discharge end of the pyrolysis furnace. The pulverized coal drying device includes a drying base and a drying cylinder rotatably mounted on the drying base. A rotary drive is connected to the outside of the drying cylinder. An annular groove is provided in the circumferential direction of the drying cylinder. An air guide ring is rotatably mounted on the outside of the annular groove and is sealed to the air guide ring. The air guide ring is connected to an air inlet pipe that communicates with the annular groove. Several spiral air pipes are evenly distributed in the circumferential direction on the inner wall of the drying cylinder. The air inlet end of the spiral air pipe communicates with the annular groove, and a filter screen is provided at the air outlet end of the spiral air pipe. The pyrolysis furnace includes a furnace body and a heating device. The heating device includes a heating jacket fixedly installed on the outside of the furnace body. Two partition plates are provided between the heating jacket and the furnace body. The two partition plates divide the heating jacket into three buffer spaces. The partition plates can move along the axis of the furnace body. Multiple hot air inlets communicating with the buffer spaces are uniformly arranged along the axial direction of the side wall of the furnace body. Each buffer space is connected to a hot air carrier pipe. The furnace body is equipped with a first plate conveyor, a second plate conveyor, and a third plate conveyor connected in sequence. The first plate conveyor is located at the feed end of the pyrolysis furnace, and the third plate conveyor is located at the discharge end of the pyrolysis furnace.

[0007] Preferably, the left and right ends of the drying cylinder are rotatably connected to a cover, the cover is connected to the drying base, one cover is provided with a feed hopper, and the other cover is provided with a discharge hopper and an exhaust pipe.

[0008] Preferably, the spiral vent pipe protrudes from the inner wall of the drying cylinder, and the spiral vent pipe is provided in at least two specifications, with at least one specification of the spiral vent pipe extending to the cover where the discharge hopper is provided.

[0009] Preferably, the feeding end of the furnace body is provided with a feeding device, which includes a feeding plate and feeding blocks fixedly disposed on the feeding plate. The feeding blocks are provided in multiple layers, with the number of feeding blocks in each layer increasing sequentially from top to bottom. The fabric feeding device is located above the first plate conveyor.

[0010] Preferably, the heating sleeve is rotatably provided with two screws, which are threadedly connected to the corresponding partition plates, and one end of the screws extends out of the heating sleeve.

[0011] Preferably, the steel plates of the first plate conveyor, the second plate conveyor and the third plate conveyor are provided with through holes, and the middle of the first plate conveyor, the second plate conveyor and the third plate conveyor are provided with coal guide plates. The height of the two sides of the coal guide plates is lower than the height of the middle, and the two sides of the coal guide plates extend out of the corresponding plate conveyor. A coal collection device is installed at the lower end of the furnace body.

[0012] Preferably, the coal collection device includes an arc-shaped groove located at the lower end of the furnace body. The two ends of the arc-shaped groove are connected to the inner wall of the furnace body through arc-shaped plates. A propeller is rotatably installed inside the arc-shaped groove, and one end of the propeller extends out of the furnace body and is connected to a drive motor.

[0013] Preferably, a heating device and a temperature controller are provided in the buffer space.

[0014] Preferably, the gas treatment device includes a heat exchanger and a dust collector, and the heat exchanger is connected to the gas inlet pipe through an insulated pipe.

[0015] The beneficial effects of this invention compared to the prior art are as follows: 1. This invention recovers the waste heat from the oil and gas generated in the gas processing device through a heat exchanger and insulated pipes, and introduces it into the spiral ventilation pipe of the drying device as a heat source for drying pulverized coal, effectively reducing the overall external energy consumption of the system and realizing the internal cascade utilization of energy.

[0016] 2. This invention features spiral venting pipes evenly distributed circumferentially within the drying cylinder. These pipes not only stir and agitate the pulverized coal during rotation to prevent clumping, but also directly supply hot air into the coal powder, achieving dynamic, penetrating drying and significantly improving drying speed and uniformity. The spiral venting pipes protrude from the inner wall, combining lifting and propulsion functions to ensure the pulverized coal moves smoothly and continuously forward within the drying cylinder and is ultimately discharged smoothly from the outlet hopper.

[0017] 3. This invention divides the pyrolysis furnace into a preheating section, a main distillation section, and an upgrading section, and utilizes movable partitions to independently control three buffer spaces, achieving precise and independent regulation of the length and temperature of each section. This allows for flexible optimization of the process based on the characteristics of different coal types and target product requirements, significantly improving the quality and yield of pyrolysis products. The use of a three-stage independently controllable plate conveyor allows for precise control of the residence time of pulverized coal in each pyrolysis stage, ensuring that the pulverized coal reaches its optimal reaction state at each stage, thereby guaranteeing the quality of the final solid product and the efficient generation of oil and gas products. The material distribution device, through a multi-layered material distribution block design, ensures that the pulverized coal is evenly distributed on the first plate conveyor, avoiding the problem of incomplete local pyrolysis caused by uneven material distribution. Attached Figure Description

[0018] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0019] Figure 1 This is a schematic diagram of the overall invention; Figure 2 This is a schematic diagram of a pulverized coal drying device. Figure 3 This is a cross-sectional view of a pulverized coal drying device. Figure 4 for Figure 3 A magnified view of part A in the image; Figure 5 This is a schematic diagram of the pyrolysis furnace structure; Figure 6 This is a cross-sectional view of a pyrolysis furnace; Figure 7 for Figure 5 Sectional view along line AA; Figure 8 This is a schematic diagram of the fabric distribution device.

[0020] In the diagram: 1-Pyrolysis furnace; 11-Furnace body; 12-Heating jacket; 13-Divider plate; 14-Hot air inlet; 15-First plate conveyor; 16-Second plate conveyor; 17-Third plate conveyor; 18-Screw; 19-Coal guide plate; 2-Powdered coal drying device; 21-Drying base; 22-Drying cylinder; 23-Rotary drive; 24-Annular trough; 25-Guide ring; 26-Inlet pipe; 27-Spiral ventilation pipe; 28-Cap; 29-Feed hopper; 210-Discharge hopper; 211-Exhaust pipe; 3-Gas processing device; 31-Heat exchanger; 32-Dust collector; 4-Solid collection cart; 5-Buffer space; 51-Hot carrier gas pipeline; 6-Coal collection device; 61-Arc trough; 62-Arc plate; 63-Propeller; 7-Bulking device; 71-Bulking plate; 72-Bulking block. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] like Figures 1 to 8 As shown, a low-temperature pyrolysis system for low-rank coal powder includes a pyrolysis furnace 1. A coal powder drying device 2 is connected to the feed end of the pyrolysis furnace 1 to remove moisture from the coal powder. A gas treatment device 3 and a solid collection vehicle 4 are connected to the discharge end of the pyrolysis furnace 1. The gas treatment device 3 is used to remove dust and cool the generated oil and gas, and the solid collection vehicle 4 is used to collect the generated solid products.

[0023] The pulverized coal drying device 2 includes a drying base 21 and a drying cylinder 22 rotatably mounted on the drying base 21. A rotary drive 23 is externally connected to the drying cylinder 22, driving the drying cylinder 22 to rotate. Covers 28 are rotatably connected to the left and right ends of the drying cylinder 22, respectively. The covers 28 are connected to the drying base 21. One cover 28 is equipped with a feed hopper 29, and the other cover is equipped with a discharge hopper 210 and an exhaust pipe 211. The feed hopper 29 is used for feeding pulverized coal, the discharge hopper 210 is used for discharging dried pulverized coal, and the exhaust pipe 211 is used for discharging gas.

[0024] Preferably, the rotary drive 23 is a rotary motor. Specifically, the rotary motor 23 is fixedly mounted on the drying base 21. A drive gear is provided on the motor shaft of the rotary motor 23. A gear ring that meshes with the drive gear is fixedly connected to the outside of the drying cylinder 22. The rotary motor 23 drives the drive gear to rotate, thereby driving the gear ring and the drying cylinder 22 to rotate.

[0025] The drying cylinder 22 has an annular groove 24 in the circumferential direction. A guide ring 25 is rotatably arranged on the outside of the annular groove 24 and is sealed to the guide ring 25. The guide ring 25 is connected to an air inlet pipe 26 that communicates with the annular groove 24. When the drying cylinder 22 rotates, the guide ring 25 can remain stationary, so air can be continuously supplied through the air inlet pipe 26.

[0026] The inner wall of the drying cylinder 22 is evenly distributed with several spiral vent pipes 27. The air inlet end of the spiral vent pipe 27 is connected to the annular groove 24, and the air outlet end of the spiral vent pipe 27 is equipped with a filter screen to prevent coal powder from entering the spiral vent pipe 27 during the drying process. By introducing hot air into the drying cylinder 22 through the spiral vent pipes 27, the drying process of the coal powder can be accelerated.

[0027] Preferably, the spiral vent pipe 27 protrudes from the inner wall of the drying cylinder 22. During the rotation of the drying cylinder 22, the protruding spiral vent pipe 27 can drive the coal powder to move slowly forward. The spiral vent pipe 27 is provided with at least two specifications to increase the disturbance to the coal powder; at least one specification of the spiral vent pipe 27 extends to the cover 28 where the discharge hopper 210 is provided, ensuring that the coal powder can finally be discharged from the discharge hopper 2.

[0028] The pyrolysis furnace 1 includes a furnace body 11 and a heating device. The furnace body 11 can be divided into a preheating section, a main distillation section, and a upgrading section along its length. In order to control the temperature of the preheating section, the main distillation section, and the upgrading section separately, the heating device includes a heating jacket 12 fixedly installed on the outside of the furnace body 11. Two partition plates 13 are provided between the heating jacket 12 and the furnace body 11. The two partition plates 13 divide the heating jacket 12 into three buffer spaces 5, which correspond to the preheating section, the main distillation section, and the upgrading section, respectively.

[0029] The partition plate 13 can move along the axis of the furnace body 11; multiple hot air inlets 14, communicating with buffer spaces 5, are evenly arranged axially on the side wall of the furnace body 11, and each buffer space 5 is connected to a hot carrier gas pipe 51. By controlling the position of the partition plate 13, the lengths of the preheating section, the main distillation section, and the upgrading section can be adjusted; the hot carrier gas in the buffer space 5 enters the corresponding working section through the hot air inlet 14. The buffer space 5 is equipped with a heating device and a temperature controller, which can heat and control the temperature of the hot carrier gas in the buffer space 5 separately.

[0030] Preferably, two screws 18 are rotatably mounted on the heating sleeve 12. The screws 18 are threadedly connected to the corresponding partition plates 13. One end of the screw 18 extends out of the heating sleeve 12. By rotating the screw 18, the corresponding partition plates 13 are moved.

[0031] In order to move the pulverized coal, the furnace body 11 is equipped with a first plate conveyor 15, a second plate conveyor 16 and a third plate conveyor 17 connected in sequence. The first plate conveyor 15 is located at the feed end of the pyrolysis furnace 1 and the third plate conveyor 17 is located at the discharge end of the pyrolysis furnace 1.

[0032] Preferably, the operating speeds of the first plate conveyor 15, the second plate conveyor 16, and the third plate conveyor 17 can be controlled separately, thereby controlling the residence time of pulverized coal in the preheating section, the main distillation section, and the upgrading section to ensure the reaction effect. The specific installation, driving, and control methods of the first plate conveyor 15, the second plate conveyor 16, and the third plate conveyor 17 can be set by those skilled in the art according to actual conditions.

[0033] A material distribution device 7 is provided at the feed end of the furnace body 11. The material distribution device 7 is located above the first plate conveyor 15. The material distribution device 7 homogenizes the pulverized coal entering from the feed end of the furnace body 11, so that it is evenly distributed on the steel plate of the first plate conveyor 15. Specifically, the material distribution device 7 includes a material distribution plate 71 and material distribution blocks 72 fixedly disposed on the material distribution plate 71. The material distribution blocks 72 are arranged in multiple layers, and the number of material distribution blocks 72 in each layer increases sequentially from top to bottom.

[0034] To improve reaction efficiency, through holes are provided on the steel plates of the first plate conveyor 15, the second plate conveyor 16, and the third plate conveyor 17. To prevent coal dust from falling through the through holes, a coal guide plate 19 is provided in the middle of each of the three plate conveyors. The height of the sides of the coal guide plate 19 is lower than the height of the middle section, and the sides of the coal guide plate 19 extend beyond the corresponding plate conveyor, so that the falling coal dust can fall from the sides of the coal guide plate 19 to the bottom of the furnace body 11 without affecting the normal operation of the plate conveyor.

[0035] A coal collection device 6 is installed at the lower end of the furnace body 11 to remove fallen coal from the furnace body 11. Specifically, the coal collection device 6 includes an arc-shaped groove 61 located at the lower end of the furnace body 11. The two ends of the arc-shaped groove 61 are connected to the inner wall of the furnace body 11 through arc-shaped plates 62. A propeller 63 is rotatably installed inside the arc-shaped groove 61. One end of the propeller 63 extends out of the furnace body 11 and is connected to a drive motor. The drive motor drives the propeller 63 to rotate, thereby moving the coal powder in the arc-shaped groove 61 forward.

[0036] Preferably, the gas processing device 3 includes a heat exchanger 31 and a dust collector 32, with the heat exchanger 31 connected to the inlet pipe 26 via an insulated pipe. The pulverized coal is dried using the waste heat from the oil and gas.

[0037] The above description only illustrates the preferred embodiments of the present invention. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention, and all such changes should be included within the protection scope of the present invention.

Claims

1. A low-temperature pyrolysis system for low-rank pulverized coal, characterized in that: It includes a pyrolysis furnace (1), a coal powder drying device (2) connected to the feed end of the pyrolysis furnace (1), and a gas processing device (3) and a solid collection vehicle (4) connected to the discharge end of the pyrolysis furnace (1). The pulverized coal drying device (2) includes a drying base (21) and a drying cylinder (22) rotatably mounted on the drying base (21). A rotary drive (23) is connected to the outside of the drying cylinder (22). An annular groove (24) is provided in the circumferential direction of the drying cylinder (22). A guide ring (25) is rotatably mounted on the outside of the annular groove (24) and sealed to the guide ring (25). The guide ring (25) is connected to an air inlet pipe (26) that communicates with the annular groove (24). Several spiral air pipes (27) are evenly distributed in the circumferential direction on the inner wall of the drying cylinder (22). The air inlet end of the spiral air pipe (27) communicates with the annular groove (24). A filter screen is provided at the air outlet end of the spiral air pipe (27). The pyrolysis furnace (1) includes a furnace body (11) and a heating device. The heating device includes a heating sleeve (12) fixedly installed on the outside of the furnace body (11). Two partition plates (13) are provided between the heating sleeve (12) and the furnace body (11). The two partition plates (13) divide the heating sleeve (12) into three buffer spaces (5). The partition plates (13) can move along the axial direction of the furnace body (11). The side wall of the furnace body (11) is uniformly provided with multiple hot air inlets (14) that communicate with the buffer spaces (5). Each buffer space (5) is connected to a hot air pipeline (51). The furnace body (11) is provided with a first plate conveyor (15), a second plate conveyor (16) and a third plate conveyor (17) connected in sequence. The first plate conveyor (15) is located at the feed end of the pyrolysis furnace (1) and the third plate conveyor (17) is located at the discharge end of the pyrolysis furnace (1).

2. The low-temperature pyrolysis system for low-rank pulverized coal according to claim 1, characterized in that: The left and right ends of the drying cylinder (22) are respectively rotatably connected to the cover (28), the cover (28) is connected to the drying base (21), one of the covers (28) is provided with a feed hopper (29), and the other cover is provided with a discharge hopper (210) and an exhaust pipe (211).

3. The low-temperature pyrolysis system for low-rank pulverized coal according to claim 2, characterized in that: The spiral vent pipe (27) protrudes from the inner wall of the drying cylinder (22). The spiral vent pipe (27) is provided with at least two specifications, and at least one specification of the spiral vent pipe (27) extends to the cover (28) provided with the discharge hopper (210).

4. The low-temperature pyrolysis system for low-rank pulverized coal according to claim 3, characterized in that: The furnace body (11) is provided with a feeding device (7) at the feeding end. The feeding device (7) includes a feeding plate (71) and feeding blocks (72) fixedly arranged on the feeding plate (71). The feeding blocks (72) are arranged in multiple layers, and the number of feeding blocks (72) in each layer increases sequentially from top to bottom. The fabric feeding device (7) is located above the first plate conveyor (15).

5. The low-temperature pyrolysis system for low-rank pulverized coal according to claim 1, characterized in that: Two screws (18) are rotatably mounted on the heating sleeve (12). The screws (18) are threadedly connected to the corresponding partition plate (13), and one end of the screws (18) extends out of the heating sleeve (12).

6. The low-temperature pyrolysis system for low-rank pulverized coal according to claim 1, characterized in that: The first plate conveyor (15), the second plate conveyor (16) and the third plate conveyor (17) are all provided with through holes on their steel plates. The first plate conveyor (15), the second plate conveyor (16) and the third plate conveyor (17) are all provided with coal guide plates (19) in the middle. The height of the two sides of the coal guide plates (19) is lower than the height of the middle. The two sides of the coal guide plates (19) extend out of the corresponding plate conveyors. A coal collection device (6) is provided at the lower end of the furnace body (11).

7. A low-temperature pyrolysis system for low-rank pulverized coal according to claim 6, characterized in that: The coal collection device (6) includes an arc-shaped groove (61) located at the lower end of the furnace body (11). The two ends of the arc-shaped groove (61) are connected to the inner wall of the furnace body (11) through an arc-shaped plate (62). A propeller (63) is rotatably installed inside the arc-shaped groove (61). One end of the propeller (63) extends out of the furnace body (11) and is connected to a drive motor.

8. The low-temperature pyrolysis system for low-rank pulverized coal according to claim 1, characterized in that: The buffer space (5) is equipped with a heating device and a temperature controller.

9. A low-temperature pyrolysis system for low-rank pulverized coal according to claim 1, characterized in that: The gas processing device (3) includes a heat exchanger (31) and a dust collector (32), wherein the heat exchanger (31) is connected to the inlet pipe (26) through an insulated pipe.

Images