A solid-liquid separation device and method for a coal gasification system

Abstract

The present invention discloses a solid-liquid separation device and method for a coal gasification system. The cavity between the hollow shaft and the inner wall of the rotating cylinder body is partitioned into a backwashing area and a negative pressure area by a first baffle and a second baffle. The rotating cylinder body is arranged in a water tank. The coal gasification liquid to be filtered passes through the filter screen on the outer ring of the rotating cylinder body and enters the negative pressure area. The filtered liquid is discharged through a drain pipe. During the rotation process, due to the negative pressure state in the negative pressure area, a fly ash membrane filter cake is formed on the outer surface of the filter screen of the rotating cylinder body. When the rotating cylinder body rotates to the backwashing area, a positive pressure is formed from the inside in the backwashing area, and the fly ash membrane filter cake on the outer surface of the filter screen loosens or falls off. Then, the fly ash membrane filter cake on the surface of the rotating cylinder body is scraped off by a scraper. The present application uses a rotating filter screen to play the role of filtering and carrying solid fly ash, which can carry the fly ash in the liquid away to achieve the preliminary purification of the water body, and can rotate cyclically to remove the fly ash membrane filter cake on the filter screen. The structure is simple, the working efficiency is high, and the floor area is small.

Description

Technical Field

[0001] The present invention belongs to a slag discharging and filtering system, and particularly relates to a solid-liquid separation device and method for a coal gasification system. Background Art

[0002] Coal gasification refers to the process in which solid fuels such as coal, coke, semi-coke, etc. react with gasifying agents under high temperature and normal pressure or pressurized conditions to be converted into gas products and a small amount of residues. The gasifying agents are mainly steam, air (or oxygen) or their mixtures, and the gasification reaction includes a series of homogeneous and heterogeneous chemical reactions. The gas products obtained have different compositions depending on the type of raw coal used, the type of gasifying agent, and the gasification process, and can be divided into air gas, semi-water gas, water gas, etc. The coal gasification process can be used to produce fuel gas for industrial kiln furnaces and city gas, and also for manufacturing synthesis gas as a raw material for synthesizing ammonia, methanol, and synthetic liquid fuels. Although the fluidized bed gasification technology has developed greatly in recent years, new pressurized fluidized bed gasification processes such as high-temperature Winkler (HTW), U-Gas, etc. and the circulating fluidized bed process (CFB) have been successively developed, which have solved to a certain extent problems such as excessive entrainment in atmospheric fluidized bed gasification, but there are still problems such as a high content of entrained matter in the gas, a high carbon content in the entrained matter and difficulty in separation, a low carbon conversion rate, a low effective component in the gas, and the requirement for high reactivity and high ash melting point of coal.

[0003] Most importantly, the black water after the slag discharging and washing unit operations in the coal gasification process has a high solid content, so it is necessary to carry out solid-liquid separation operations to reduce the energy consumption of the downstream water treatment unit. However, the traditional vacuum belt filter has a large floor area, an unsatisfactory throughput, and a high water content in the obtained filter cake. Summary of the Invention

[0004] The purpose of the present invention is to provide a solid-liquid separation device and method for a coal gasification system to overcome the deficiencies of the prior art.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A solid-liquid separation device for a coal gasification system, comprising a water tank, a rotating drum and a scraper. The rotating drum includes a hollow shaft and a rotating cylinder body. A filter screen is provided on the outer circumference of the rotating cylinder body. The rotating cylinder body is sleeved on the hollow shaft and can rotate relative to the hollow shaft. Two first baffles and second baffles are fixed on the hollow shaft at an included angle. One end of each of the first baffle and the second baffle is fixed on the hollow shaft, and the other three sides of the first baffle and the second baffle are in contact with the inner wall of the rotating cylinder body. The first baffle and the second baffle divide the cavity between the hollow shaft and the inner wall of the rotating cylinder body into two independent spaces. One space is the backwashing area, and the other space is the negative pressure area; through holes are provided on the shaft wall of the hollow shaft in both independent spaces. An air blowing pipe, a negative pressure pipe and a drain pipe are provided in the hollow shaft. One end of the air blowing pipe is communicated with the through hole on the hollow shaft in the backwashing area, and one end of the negative pressure pipe is communicated with the through hole on the hollow shaft in the negative pressure area; the rotating cylinder body is arranged in the water tank, and the scraper is fixed on the outer side of the rotating cylinder body, and one end of the scraper is in contact with the outer side of the rotating cylinder body.

[0007] Further, the lower end of the first baffle is in contact with the hollow shaft, the left and right sides of the first baffle are in contact with the inner wall of the rotating cylinder body, the upper end of the first baffle is in contact with the circumferential inner wall of the rotating cylinder body, the lower end of the second baffle is in contact with the hollow shaft, the left and right sides of the second baffle are in contact with the inner wall of the rotating cylinder body, the upper end of the second baffle is in contact with the circumferential inner wall of the rotating cylinder body, and the rotating cylinder body rotates relative to the first baffle, the second baffle and the hollow shaft.

[0008] Further, the included angle between the first baffle and the second baffle is 30°-60°, and the included angle between the second baffle 8 and the horizontal plane is 10°-20°.

[0009] Further, a stirrer is provided in the water tank, and the water tank is an arc-shaped water tank.

[0010] Further, a water inlet is provided on one side of the water tank, and an overflow port is provided on the other side. The overflow port is higher than the drain port at the lower end of the drain pipe and lower than the lowest surface of the hollow shaft.

[0011] Further, a boss is provided on one side of the hollow shaft, and a shoulder is provided on the other side. The rotating cylinder body is sleeved on the hollow shaft. One end of the outer side of the rotating cylinder body is in contact with the end face of the boss, and the inner side of the other end of the rotating cylinder body is in contact with the end face of the shoulder. A locking nut is provided at the outer end of the hollow shaft.

[0012] Further, sealing gaskets are provided between the rotating cylinder body and the end faces of the boss and the shoulder, and bearings are provided between the rotating cylinder body and the hollow shaft.

[0013] Further, an axial clamping groove is provided on the hollow shaft, and both the first baffle and the second baffle are nested and clamped in the axial clamping groove.

[0014] Further, the other end of the air blowing pipe is connected to an air pump, and the other end of the negative pressure pipe is connected to a vacuum pump.

[0015] A solid-liquid separation method for a coal gasification system, comprising the following steps:

[0016] S1, Install the solid-liquid separation device at the upper end of the water tank, and place the rotating cylinder in the water tank;

[0017] S2, Inject the liquid to be filtered into the water tank so that the liquid level of the liquid to be filtered is higher than the drainage outlet at the lower end of the drain pipe and lower than the lower surface of the hollow shaft; drive the rotating cylinder to rotate and suck vacuum into the negative pressure area at the same time to form a negative pressure in the negative pressure area inside the rotating cylinder, and inject positive pressure into the backwashing area at the same time. Continuously drive the rotating cylinder to rotate to complete the primary filtration and filter residue separation.

[0018] Compared with the prior art, the present invention has the following beneficial technical effects:

[0019] A solid-liquid separation device for a coal gasification system of the present invention is provided with a filter screen around the outer circumference of the rotating cylinder. The rotating cylinder is sleeved on the hollow shaft and can rotate relative to the hollow shaft. Two first baffles and second baffles arranged at an angle are fixed on the hollow shaft. The remaining three sides of the first baffle and the second baffle are in contact with the inner wall of the rotating cylinder. The cavity between the hollow shaft and the inner wall of the rotating cylinder is partitioned into a backwashing area and a negative pressure area by the first baffle and the second baffle; through holes are opened on the shaft wall of the hollow shaft in both independent spaces. One end of the blowing pipe is connected to the through hole on the hollow shaft in the backwashing area, and one end of the negative pressure pipe is connected to the through hole on the hollow shaft in the negative pressure area. The rotating cylinder is arranged in the water tank. By rotating the rotating cylinder, air is blown into the backwashing area through the blowing pipe to form a positive pressure in the backwashing area; the negative pressure pipe sucks air to make the negative pressure area in a negative pressure state. The liquid to be filtered of coal gasification passes through the filter screen on the outer circle of the rotating cylinder and enters the negative pressure area to complete the primary filtration. The filtered liquid is discharged through the drain pipe; during the rotation of the rotating cylinder, since the negative pressure area is in a negative pressure state, a fly ash membrane filter cake is formed on the outer surface of the filter screen of the rotating cylinder. When the rotating cylinder rotates to the backwashing area, a positive pressure is formed from the inside in the backwashing area, and the fly ash membrane filter cake on the outer surface of the filter screen loosens or falls off. Then, the fly ash membrane filter cake on the surface of the rotating cylinder is scraped off by a scraper to complete a solid-liquid separation operation. The filter screen plays the role of filtering and carrying solid fly ash, can take the fly ash in the liquid away to achieve the preliminary purification of the water body, and can rotate cyclically to remove the fly ash membrane filter cake on the filter screen, with high working efficiency, avoiding the blockage problem caused by the immobility of the transmission filter screen, simple structure, and small floor area.

[0020] Further, the included angle between the first baffle and the second baffle is 30°-60°, and the included angle between the second baffle and the horizontal plane is 10°-20°, forming a small-area backwashing area, which is beneficial to the falling off of the fly ash membrane filter cake.

[0021] Further, a stirrer is provided in the water tank, and the water tank adopts an arc-shaped water tank to prevent liquid precipitation.

[0022] Furthermore, a water inlet is provided on one side of the water tank, and an overflow port is provided on the other side, which can effectively prevent the liquid level from being too high.

[0023] Furthermore, a boss is provided on one side of the hollow shaft, and a shaft shoulder is provided on the other side. The rotating cylinder is sleeved on the hollow shaft. The outer side of one end of the rotating cylinder contacts the end face of the boss, and the inner side of the other end of the rotating cylinder contacts the end face of the shaft shoulder. A locking nut is provided at the outer end of the hollow shaft. The structure is simple and convenient for installation, maintenance and cleaning.

[0024] Furthermore, an axial card slot is provided on the hollow shaft, and both the first baffle and the second baffle are nested and clamped in the axial card slot. The structure is simple and convenient for installation and disassembly.

[0025] A solid-liquid separation method of a coal gasification system according to the present invention uses the above solid-liquid separation device, which is installed at the upper end of the water tank, and the rotating cylinder is placed in the water tank; by injecting the liquid to be filtered into the water tank to make the liquid level of the liquid to be filtered higher than the drainage port at the lower end of the drain pipe and lower than the lower surface of the hollow shaft; driving the rotating cylinder to rotate while sucking vacuum into the negative pressure area to form a negative pressure in the negative pressure area of the rotating cylinder, and injecting positive pressure into the backwashing area at the same time, and continuously driving the rotating cylinder to rotate to complete the primary filtration and filter residue separation. The method is simple and the filtration efficiency is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic structural diagram of the solid-liquid separation device in the embodiment of the present invention.

[0027] Figure 2 It is a schematic installation structure diagram of the rotating cylinder in the embodiment of the present invention.

[0028] Figure 3 It is a schematic connection structure diagram of the application system of the solid-liquid separation device in the embodiment of the present invention.

[0029] Wherein, 1. water tank; 2. drum; 3. scraper; 4. hollow shaft; 5. rotating cylinder; 6. filter screen; 7. first baffle; 8. second baffle; 9. blowing pipe; 10. negative pressure pipe; 11. drain pipe; 12. stirrer; 13. water inlet; 14. overflow port; 15. boss; 16. locking nut; 17. bearing; 18. driving wheel; 19. driving device; 20. cyclone separator. DETAILED DESCRIPTION OF THE INVENTION

[0030] The present invention will be further described in detail below with reference to the accompanying drawings:

[0031] As Figures 1 to 3As shown in the figure, a solid-liquid separation device for a coal gasification system includes a water tank 1, a rotating drum 2 and a scraper 3. The rotating drum 2 includes a hollow shaft 4 and a rotating cylinder 5. A filter screen 6 is provided in a circumferential manner on the outer circumference of the rotating cylinder 5. The rotating cylinder 5 is sleeved on the hollow shaft 4 and can rotate relative to the hollow shaft 4. Two first baffles 7 and second baffles 8 are fixed on the hollow shaft 4 at an included angle. One end of each of the first baffle 7 and the second baffle 8 is fixed on the hollow shaft 4, and the remaining three sides of the first baffle 7 and the second baffle 8 are in contact with the inner wall of the rotating cylinder 5. The first baffle 7 and the second baffle 8 divide the cavity between the hollow shaft 4 and the inner wall of the rotating cylinder 5 into two independent spaces. One space is the backwashing area, and the other space is the negative pressure area; through holes are provided on the shaft wall of the hollow shaft 4 in both independent spaces. An air blowing pipe 9, a negative pressure pipe 10 and a drain pipe 11 are provided in the hollow shaft 4. One end of the air blowing pipe 9 is communicated with the through hole on the hollow shaft 4 in one of the independent spaces, one end of the negative pressure pipe 10 is communicated with the through hole on the hollow shaft 4 in the other independent space, one end of the drain pipe 11 is communicated with an external water pumping device through the hollow shaft 4, and the other end passes through the shaft wall of the hollow shaft 4 and is located in the negative pressure area space; in this application, the air blowing pipe 9 is communicated with the through hole on the hollow shaft 4 in the backwashing area, and the negative pressure pipe 10 is communicated with the through hole on the hollow shaft 4 in the negative pressure area; the rotating cylinder 5 is arranged in the water tank 1 of the water tank, and the scraper 3 is fixed on the outer side of the rotating cylinder 5. One end of the scraper 3 is in contact with the outer side of the rotating cylinder 5. During use, the coal gasification liquid to be filtered is injected into the water tank. The liquid level in the water tank is lower than the lowest end of the backwashing area in the rotating cylinder 5, and the liquid level in the water tank is higher than the drainage port of the drain pipe 11. During the filtering process, the rotating cylinder 5 is rotated, and air is blown into the backwashing area by the air blowing pipe 9 to form a positive pressure in the backwashing area; the negative pressure pipe 10 sucks air to make the negative pressure area in a negative pressure state. The coal gasification liquid to be filtered passes through the filter screen 6 on the outer ring of the rotating cylinder 5 and enters the negative pressure area to complete the primary filtration. The filtered liquid is discharged through the drain pipe 11; during the rotation of the rotating cylinder 5, due to the negative pressure state in the negative pressure area, a fly ash membrane filter cake is formed on the outer surface of the filter screen 6 of the rotating cylinder 5. The first baffle 7, the second baffle 8 and the hollow shaft 4 are all fixed. When the rotating cylinder 5 rotates to the backwashing area, a positive pressure is formed from the inside in the backwashing area, and the fly ash membrane filter cake on the outer surface of the filter screen 6 loosens or falls off. Then, the fly ash membrane filter cake on the surface of the rotating cylinder 5 is scraped off by the scraper to complete a solid-liquid separation operation. The filter screen 6 plays a role in filtering and carrying solid fly ash, can carry the fly ash in the liquid away to realize the preliminary purification of the water body, and can rotate cyclically to remove the fly ash membrane filter cake on the filter screen. The structure is simple, the working efficiency is high, and the floor area is small. The other end of the air blowing pipe 9 is connected to an air pump, and the other end of the negative pressure pipe 10 is connected to a vacuum pump.

[0032] The installation structures of the first baffle 7 and the second baffle 8 are the same, that is: the lower end of the first baffle 7 contacts the hollow shaft 4, the left and right sides of the first baffle 7 contact the inner wall of the rotating cylinder 5, the upper end of the first baffle 7 contacts the circumferential inner wall of the rotating cylinder 5, the lower end of the second baffle 8 contacts the hollow shaft 4, the left and right sides of the second baffle 8 contact the inner wall of the rotating cylinder 5, the upper end of the second baffle 8 contacts the circumferential inner wall of the rotating cylinder 5. The first baffle 7, the second baffle 8 and the hollow shaft 4 are fixed, and the rotating cylinder 5 rotates relative to the first baffle 7, the second baffle 8 and the hollow shaft 4.

[0033] The included angle between the first baffle 7 and the second baffle 8 is 30° - 60°, the included angle between the second baffle 8 and the horizontal plane is 10° - 20°, the included angle between the first baffle 7 and the horizontal plane is 40° - 80°. The acute angle area formed between the first baffle 7 and the second baffle 8 is the backwashing area, and the backwashing area is located at the end of the rotation operation of the rotating cylinder, that is, after the rotating cylinder rotates the filter screen through the backwashing area, it enters the liquid in the water tank.

[0034] A stirrer 12 is provided in the water tank 1 for stirring the liquid in the water tank to prevent precipitation in the water tank and improve the liquid purification efficiency. The water tank 1 adopts an arc-shaped water tank, which is similar to the arc of the rotating cylinder 5; a water inlet 13 is provided on one side of the water tank 1, and an overflow port 14 is provided on the other side. The overflow port 14 is higher than the drainage port at the lower end of the drain pipe 11, and the overflow port 14 is lower than the lowest surface of the hollow shaft 4 to prevent the liquid from being discharged from the hollow shaft 4 when passing through the negative pressure area.

[0035] As Figure 2 shown, taking the installation surface of the first baffle 7 as the section, the rotating cylinder 5 is sectioned; a boss 15 is provided on one side of the hollow shaft 4, and a shaft shoulder is provided on the other side. The rotating cylinder 5 is sleeved on the hollow shaft 4. One end outer side of the rotating cylinder 5 contacts the end face of the boss 15, and the inner side face of the other end of the rotating cylinder 5 contacts the end face of the shaft shoulder. A locking nut 16 is provided at the outer end of the hollow shaft 4, and the rotating cylinder 5 is circumferentially fixed on the hollow shaft 4 through the locking nut 16; sealing gaskets are provided between the rotating cylinder 5 and the end faces of the boss 15 and the shaft shoulder. A bearing 17 is provided between the rotating cylinder 5 and the hollow shaft 4 to reduce the friction between the rotating cylinder 5 and the hollow shaft 4, improve the rotation efficiency and reduce the energy consumption.

[0036] Axial grooves are provided on the hollow shaft 4, and both the first baffle 7 and the second baffle 8 are nested and clamped in the axial grooves. During installation, first fix the frame of the rotating cylinder 5 on the hollow shaft 4, then insert the first baffle 7 and the second baffle 8 into the axial grooves on the hollow shaft 4 from the outer ring of the rotating cylinder 5, then install the filter screen 6 on the outer ring of the rotating cylinder 5, and finally fixedly install the scraper 3 on the outside of the rotating cylinder.

[0037] A driving wheel 18 is provided on the outside of the rotating cylinder 5 and is driven by a driving device 19, with a simple structure and convenient installation and maintenance. As Figure 1As shown, the driving device 19 uses a driving motor. The driving motor is connected to the driving wheel 18 by a belt, with a simple structure and reduced installation space. Alternatively, the driving motor can be directly connected to the driving wheel through a gear or a driving shaft.

[0038] The solid content of the black water is about 30%. The working pressure of the vacuum pump is negative pressure -0.1 KPa, the motor power is 0.75 kw, and the processing capacity is 0.6 kg / S. Different pore-sized filter meshes can be set according to the particle size of the liquid waste residue to be filtered. It can handle fly ash particles with medium particle sizes between 1 and 80 μm.

[0039] A baffle is provided outside the scraper 3, and a conveyor belt is provided at the bottom of the scraper 3. The filter cake unloaded by the scraper is conveyed by the conveyor belt to the inlet of the cyclone separator 20 for secondary filtration operation. A layer of filter cloth is wrapped on the inner wall of the cyclone separator 20 to separate the water in the filter cake through centrifugal action. The filter cloth can be disassembled and cleaned for repeated use. The separation requirements are achieved by adjusting the rotation speed of the cyclone separator 20. Except for the backwashing area, the space between the rotating cylinder 5 and the hollow shaft 4 is in a negative pressure state, and backwashing operation is performed after the rotating cylinder 5 rotates to the backwashing area. Since the liquid flowing out of the overflow port contains some fly ash solid particles, the overflow liquid is circulated to the water tank to separate the fly ash particles again. Using the solid-liquid separation device of the present application for preliminary solid separation and introducing a rotary vacuum separator at the filter cake collection place can control the water content of the filter cake within 2%, effectively improving the solid-liquid separation effect and having certain industrial application value.

[0040] Based on the above solid-liquid separation method of the coal gasification system using the solid-liquid separation device for the coal gasification system, it includes the following steps:

[0041] S1, install the solid-liquid separation device at the upper end of the water tank, and place the rotating cylinder 5 in the water tank 1;

[0042] S2. Inject the liquid to be filtered into the water tank 1 so that the liquid level of the liquid to be filtered is higher than the drainage outlet at the lower end of the drain pipe 11 and lower than the lower surface of the hollow shaft 4; drive the rotating cylinder 5 to rotate and suck vacuum into the negative pressure area at the same time to form a negative pressure in the negative pressure area inside the rotating cylinder 5, and inject positive pressure into the backwashing area at the same time. The gasified liquid to be filtered passes through the filter screen 6 on the outer ring of the rotating cylinder 5 and enters the negative pressure area to complete the primary filtration, and the filtered liquid is discharged through the drain pipe 11; during the rotation of the rotating cylinder 5, due to the negative pressure state in the negative pressure area, a fly ash membrane filter cake is formed on the outer surface of the filter screen 6 of the rotating cylinder 5. When the rotating cylinder 5 rotates to the backwashing area, a positive pressure is formed from the inside in the backwashing area, and the fly ash membrane filter cake on the outer surface of the filter screen 6 loosens or falls off, and then the fly ash membrane filter cake on the surface of the rotating cylinder 5 is scraped off by the scraper to complete a solid-liquid separation operation. The present invention is simple and convenient, can quickly realize the filtration of the liquid, and can clean the filter screen in real time to prevent the filter screen from being blocked and reducing the filtration efficiency. The structure of this application is simple and easy to install. Adopting a circulating rotation filtration structure can keep the filter screen in an effective working state and achieve efficient filtration.

Claims

1. A solid-liquid separation device for a coal gasification system, characterized in that, it includes a water tank (1), a rotating drum (2) and a scraper (3). The rotating drum (2) includes a hollow shaft (4) and a rotating cylinder body (5). A filter screen (6) is provided in a circumferential circle on the outer circumference of the rotating cylinder body (5). The rotating cylinder body (5) is sleeved on the hollow shaft (4) and can rotate relative to the hollow shaft (4). Two first baffles (7) and second baffles (8) arranged at an angle are fixed on the hollow shaft (4). One end of each of the first baffle (7) and the second baffle (8) is fixed on the hollow shaft (4). The remaining three sides of the first baffle (7) and the second baffle (8) are in contact with the inner wall of the rotating cylinder body (5). The first baffle (7) and the second baffle (8) divide the cavity between the hollow shaft (4) and the inner wall of the rotating cylinder body (5) into two independent spaces. One space is the backwashing area, and the other space is the negative pressure area. Through holes are provided on the shaft wall of the hollow shaft (4) in both independent spaces. A blow pipe (9), a negative pressure pipe (10) and a drain pipe (11) are provided in the hollow shaft (4). One end of the blow pipe (9) is communicated with the through hole on the hollow shaft (4) in the backwashing area, and one end of the negative pressure pipe (10) is communicated with the through hole on the hollow shaft (4) in the negative pressure area. The rotating cylinder body (5) is arranged in the water tank (1) of the water tank. The scraper (3) is fixed on the outer side of the rotating cylinder body (5). One end of the scraper (3) is in contact with the outer side of the rotating cylinder body (5). Characterized in that, the lower end of the first baffle (7) is in contact with the hollow shaft (4), the left and right sides of the first baffle (7) are in contact with the inner wall of the rotating cylinder body (5), the upper end of the first baffle (7) is in contact with the circumferential inner wall of the rotating cylinder body (5), the lower end of the second baffle (8) is in contact with the hollow shaft (4), the left and right sides of the second baffle (8) are in contact with the inner wall of the rotating cylinder body (5), the upper end of the second baffle (8) is in contact with the circumferential inner wall of the rotating cylinder body (5), and the rotating cylinder body (5) rotates relative to the first baffle (7), the second baffle (8) and the hollow shaft (4). Characterized in that, the included angle between the first baffle (7) and the second baffle (8) is 30° - 60°, and the included angle between the second baffle (8) and the horizontal plane is 10° - 20°.

2. The solid-liquid separation device for a coal gasification system according to claim 1, characterized in that, a stirrer (12) is provided in the water tank (1), and the water tank (1) adopts an arc-shaped water tank.

3. The solid-liquid separation device for a coal gasification system according to claim 1, characterized in that, a water inlet (13) is arranged on one side of the water tank (1), and an overflow port (14) is arranged on the other side. The overflow port (14) is higher than the drain port at the lower end of the drain pipe (11), and the overflow port (14) is lower than the lowest surface of the hollow shaft (4).

4. The solid-liquid separation device for a coal gasification system according to claim 1, characterized in that, a boss (15) is provided on one side of the hollow shaft (4), and a shaft shoulder is provided on the other side. The rotating cylinder body (5) is sleeved on the hollow shaft (4). One end outside the rotating cylinder body (5) is in contact with the end face of the boss (15), and the inner side face of the other end of the rotating cylinder body (5) is in contact with the end face of the shaft shoulder. A locking nut (16) is provided at the outer end of the hollow shaft (4).

5. A solid-liquid separation device for a coal gasification system according to claim 4, characterized in that, sealing gaskets are provided between the rotating cylinder body (5) and the boss (15) and the end face of the shaft shoulder, and a bearing (17) is provided between the rotating cylinder body (5) and the hollow shaft (4).

6. A solid-liquid separation device for a coal gasification system according to claim 1, characterized in that, axial clamping grooves are provided on the hollow shaft (4), and the first baffle (7) and the second baffle (8) are both nested and clamped in the axial clamping grooves.

7. A solid-liquid separation device for a coal gasification system according to claim 1, characterized in that, the other end of the air blowing pipe (9) is connected to an air pump, and the other end of the negative pressure pipe (10) is connected to a vacuum pump.

8. A solid-liquid separation method for a coal gasification system based on the solid-liquid separation device for a coal gasification system according to claim 1, characterized in that, it includes the following steps: S1, install the solid-liquid separation device at the upper end of the water tank, and place the rotating cylinder body in the water tank; S2, inject the liquid to be filtered into the water tank so that the liquid level of the liquid to be filtered is higher than the drainage outlet at the lower end of the drain pipe and lower than the lower surface of the hollow shaft; drive the rotating cylinder body to rotate and at the same time suck vacuum in the negative pressure area to form negative pressure in the negative pressure area of the rotating cylinder body, and at the same time inject positive pressure into the back blowing area, and continuously drive the rotating cylinder body to rotate to complete primary filtration and filter residue separation.

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