Integrated fluidized bed gasifier sludge flash drying system

Abstract

The application discloses a sludge flash drying system integrated with a fluidized bed gasification furnace, which comprises a wet sludge conveying subsystem, an outlet of the wet sludge conveying subsystem is communicated with an inlet of a sludge flash drying subsystem, an outlet of the sludge flash drying subsystem is connected with an inlet of a gas-solid separator, an outlet of the gas-solid separator is communicated with an inlet of a dry sludge conveying subsystem, an outlet of the dry sludge conveying subsystem is communicated with an inlet of a fluidized bed gasification furnace subsystem, an outlet of the fluidized bed gasification furnace subsystem is communicated with a gas-gas heat exchanger, an outlet of the gas-gas heat exchanger is communicated with an inlet of an external combustion chamber, and an outlet of the external combustion chamber is communicated with a drying gas inlet of the sludge flash drying subsystem. The application recycles the heat value generated in the sludge gasification process for sludge flash drying, so that the energy consumption is low, and the economic cost of system operation is reduced. Due to the high sludge drying efficiency and the strong sludge disposal capacity, the resourceization, reduction and efficient clean utilization of sludge can be realized.

Description

Technical Field

[0001] This invention belongs to the field of sludge treatment technology, specifically, it relates to a sludge flash drying system with an integrated fluidized bed gasifier. Background Technology

[0002] Sludge is a solid sediment produced during urban wastewater treatment. If not properly treated, it can cause significant harm to water bodies, soil, and the atmosphere, impacting the living environment. Every 10,000 tons of wastewater produces 5-8 tons of wet sludge with an 80% water content. Currently, my country primarily treats sludge through sanitary landfill, supplemented by anaerobic digestion, aerobic fermentation, and drying / incineration / co-firing. While sanitary landfill is energy-efficient and cost-effective, it doesn't reduce sludge volume. Large landfills occupy limited land resources and pose risks of soil and water pollution. Anaerobic digestion and aerobic fermentation can reduce sludge volume by 50-70%, but their main drawbacks are large land area requirements and the generation of large amounts of biogas slurry, biogas residue, and odor emissions, severely impacting the human living environment. Drying / incineration / co-firing can reduce sludge volume by approximately 90%, but its corresponding disadvantages are higher energy consumption and cost. Wet sludge has a high moisture content, generally greater than 60%. However, after dehydration and drying, sludge with a moisture content below 30% can achieve a calorific value of approximately 1500 kcal / kg, demonstrating good potential for thermal resource utilization. Overall, the trend towards sludge treatment and disposal that emphasizes volume reduction, resource recovery, harmlessness, and stabilization, such as thermal treatment methods like drying and incineration, and pyrolysis and gasification, is gradually becoming mainstream. Summary of the Invention

[0003] The purpose of this invention is to address the deficiencies in the existing technical field and provide a sludge flash drying system with an integrated fluidized bed gasifier. By coupling the fluidized bed gasifier and the sludge flash drying device, a highly efficient closed sludge treatment and disposal system that can fully utilize the calorific value of the sludge is constructed, realizing the resource utilization, volume reduction, and efficient and clean utilization of sludge.

[0004] To achieve the above objectives, the technical solution of this invention is as follows:

[0005] A sludge flash drying system with an integrated fluidized bed gasifier includes a wet sludge conveying subsystem. The outlet of the wet sludge conveying subsystem is connected to the inlet of the sludge flash drying subsystem. The outlet of the sludge flash drying subsystem is connected to the inlet of a gas-solid separator. The outlet of the gas-solid separator is connected to the inlet of the dry sludge conveying subsystem. The outlet of the dry sludge conveying subsystem is connected to the inlet of the fluidized bed gasifier subsystem. The outlet of the fluidized bed gasifier subsystem is connected to a gas-to-gas heat exchanger. The outlet of the gas-to-gas heat exchanger is connected to the inlet of an external combustion chamber. The outlet of the external combustion chamber is connected to the drying gas inlet of the sludge flash drying subsystem.

[0006] Furthermore, the wet sludge conveying subsystem includes a wet sludge storage silo, a wet sludge feed hopper, and a wet sludge conveying device. The wet sludge feed hopper connects the wet sludge storage silo and the wet sludge conveying device. The wet sludge conveying device is a screw conveyor. One end of the screw conveyor is connected to the outlet of the wet sludge feed hopper, and the other end of the screw conveyor is connected to the sludge flash drying subsystem.

[0007] Furthermore, the sludge flash drying subsystem includes a sludge flash drying device and a drive motor; the top surface of the outer shell of the sludge flash drying device is provided with an upper bearing, and the bottom surface of the outer shell of the sludge flash drying device is provided with a lower bearing, the upper bearing and the lower bearing are arranged opposite each other, the top end of the rotating shaft is connected to the drive motor, the drive motor can drive the rotating shaft to rotate, and the rotating shaft is connected to both the upper bearing and the lower bearing; the rotating shaft is clearance-fitted to both the upper bearing and the lower bearing, and the rotating shaft can rotate around the inner wall of the upper bearing and the lower bearing;

[0008] Furthermore, the lower side of the outer shell of the sludge flash drying device is provided with a wet sludge inlet and a drying gas inlet for the wet sludge to enter. The wet sludge inlet is located above the drying gas inlet, and the wet sludge inlet and the drying gas inlet are located on the same side of the sludge flash drying device.

[0009] The wet sludge inlet is connected to the wet sludge conveying device. The wet sludge inlet is located above the air distribution plate, which is located inside the sludge flash drying device. The end of the air distribution plate is connected to the inner wall of the shell of the sludge flash drying device. The air distribution plate has evenly arranged holes. The drying gas inlet is located below the air distribution plate.

[0010] The upper side of the outer shell of the sludge flash drying device is provided with an outlet for the discharge of granular dry sludge and exhaust gas. The outlet is connected to the gas-solid separator through a pipe.

[0011] Furthermore, the sludge flash drying device is equipped with a fixed component and a rotating component; the fixed component includes a limiting plate located above the inside of the sludge flash drying device, an air distribution plate located below the inside, and multiple fixed blade holders located between the limiting plate and the air distribution plate, with one end of the fixed blade holders connected to the inner wall of the sludge flash drying device shell.

[0012] Furthermore, the end of the limiting disc is connected to the inner wall of the shell of the sludge flash drying device, and a through hole is provided in the center of the limiting disc. The diameter of the through hole on the limiting disc is larger than the diameter of the rotating shaft. A through hole is provided in the middle of the air distribution plate. The diameter of the through hole in the middle of the air distribution plate is larger than the diameter of the rotating shaft. The distance between each pair of fixed blade holders gradually decreases from bottom to top. Two fixed blade holders set at the same height are symmetrically arranged with respect to the rotating shaft. The distance between the tops of the two fixed blade holders symmetrically arranged with respect to the rotating shaft is larger than the diameter of the rotating shaft.

[0013] The rotating component includes multiple rotating blades and a lift fan disposed inside the sludge flash drying device and connected to the rotating shaft; one end of each rotating blade is fixedly connected to the rotating shaft, and the distance between each pair of rotating blades gradually decreases from bottom to top, and the diameter of the rotating blades is smaller than the inner diameter of the outer shell; the lift fan is connected to the rotating shaft, and the rotation of the rotating shaft drives the lift fan to rotate, and the lift fan is disposed below the air distribution plate.

[0014] Furthermore, the gas-solid separator is a first cyclone separator, and the gas outlet of the first cyclone separator is connected to a tail gas purification device through a pipeline. The purification device is a water washing tower, an alkaline washing tower, or a UV photolysis waste gas purification device. The bottom outlet of the first cyclone separator is connected to a dry sludge storage silo through a pipeline.

[0015] Furthermore, the dry sludge conveying subsystem includes a dry sludge storage silo, a dry sludge feed hopper, and a dry sludge conveying device. The dry sludge storage silo and the dry sludge conveying device are connected through the dry sludge feed hopper. The dry sludge conveying device is a screw conveyor, with one end connected to the dry sludge feed hopper and the other end connected to the fluidized bed gasifier body.

[0016] Furthermore, the fluidized bed gasifier subsystem includes a fluidized bed gasifier body, a second cyclone separator, and a return feeder; the outlet of the fluidized bed gasifier body is connected to the second cyclone separator via a pipeline; the bottom outlet of the second cyclone separator is connected to the inlet of the return feeder via a pipeline, and the outlet of the return feeder is connected to the fluidized bed gasifier body via a pipeline; the gas outlet at the top of the second cyclone separator is connected to a gas-to-gas heat exchanger via a pipeline.

[0017] Furthermore, the gas-to-gas heat exchanger is connected to the second air compressor, and the outlet of the gas-to-gas heat exchanger containing the mixture of fuel gas and flue gas is connected to the external combustion chamber via a connecting pipe; the outlet of the air supplied by the second air compressor to the gas-to-gas heat exchanger is connected to the dry gas inlet via a connecting pipe; the first air compressor supplies air to the external combustion chamber, and the exhaust port of the external combustion chamber is connected to the dry gas inlet via a connecting pipe.

[0018] The beneficial effects of this invention are:

[0019] 1. This invention couples a fluidized bed gasifier and a sludge flash drying device, using the dried sludge with low moisture content as the raw material for the fluidized bed gasification reaction. The mixture of fuel gas and flue gas generated after the gasification of the dry sludge is further processed by the hot flue gas after combustion and the hot air after heat exchange, which together serve as the heat source for drying the wet sludge and the fluidizing medium carrying the dry sludge. Furthermore, the ash generated after the gasification reaction can be used as building material, thereby constructing a highly efficient closed-loop sludge treatment and disposal system that can fully utilize the calorific value of the sludge itself.

[0020] 2. This invention employs direct heat exchange, introducing hot flue gas and hot air together as drying gas into the sludge flash drying device for direct mixing and heat exchange with the wet sludge. The wet sludge is atomized into fine particles under the rotational cutting of the fixed blade holder and rotating blades, increasing the contact area between the fine sludge particles and the drying gas by hundreds or thousands of times. This further enhances heat and mass transfer between the wet sludge and the drying gas, resulting in a heat utilization efficiency of over 90%, high drying efficiency (the drying process of wet sludge only takes 2-7 seconds), and a high sludge collection rate (the collection rate of dried sludge after drying is greater than 99.99%).

[0021] 3. This invention adopts a closed-loop circulation system, which makes it easy to control the process conditions in each stage, such as air volume and flue gas temperature, resulting in high system safety and stability. The closed-loop "drying-gasification" treatment of dried sludge prevents odor leakage and avoids impacting the ecological environment. It fully utilizes the calorific value of the sludge itself, resulting in low energy consumption and reduced economic costs for system operation. Due to the high sludge drying efficiency and strong sludge disposal capacity, it can achieve resource recovery, volume reduction, and efficient clean utilization of sludge. It can be used to build a plant near a wastewater treatment plant, making it suitable for widespread application. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure according to the present invention.

[0023] Figure 2 This is a schematic diagram of the sludge flash drying device according to the present invention.

[0024] Figure 3 This is a schematic diagram of the structure of the fixed components of the sludge flash drying device according to the present invention.

[0025] Figure 4 This is a schematic diagram of the structure of the rotating component of the sludge flash drying device according to the present invention.

[0026] Figure 5 This is an assembly diagram of the fixed and rotating components of the sludge flash drying device according to the present invention.

[0027] In the diagram: 1-Wet sludge storage bin; 2-Wet sludge feed hopper; 3-Wet sludge conveying device; 4-External combustion chamber; 5-First air compressor; 6-Gas-to-gas heat exchanger; 7-Second air compressor; 8-Dry sludge feed hopper; 9-Dry sludge conveying device; 10-Fluidized bed gasifier body; 11-Return feeder; 12-Second cyclone separator; 13-Tail gas purification device; 14-Gas-solid separator; 15-Dry sludge storage bin; 16-Sludge flash drying device; 17-Drive motor; 18-Rotating shaft; 19-Upper bearing; 20-Outer shell; 21-Limiting plate; 22-Fixed cutter holder; 23-Rotating cutter blade; 24-Air distribution plate; 25-Lifting fan; 26-Lower bearing; 27-Drying gas inlet; 28-Exhaust outlet. Detailed Implementation

[0028] To make the purpose, technical solution, and advantages of the invention clearer, the invention will be further described below with reference to the accompanying drawings.

[0029] like Figure 1 As shown, a sludge flash drying system coupled with a fluidized bed gasifier includes a wet sludge conveying subsystem, a sludge flash drying subsystem, a dry sludge conveying subsystem, a fluidized bed gasifier subsystem, a gas-to-gas heat exchanger 6, and an external combustion chamber 4. The wet sludge conveying subsystem conveys wet sludge with a moisture content of 60-90% into the sludge flash drying subsystem. After being processed by the sludge flash drying subsystem, the wet sludge becomes dry sludge with a moisture content of 10-30%. Then, the dry sludge conveying subsystem conveys the dry sludge into the fluidized bed gasifier subsystem to undergo a gasification reaction and produce a mixture containing fuel gas and flue gas. The fuel gas and flue gas mixture enters the external combustion chamber 4 after passing through the gas-to-gas heat exchanger 6 for combustion. The hot flue gas generated by combustion and the hot air passing through the gas-to-gas heat exchanger 6 enter the sludge flash drying subsystem together to provide heat for the flash drying of the wet sludge.

[0030] The wet sludge conveying subsystem includes a wet sludge storage silo 1, a wet sludge feed hopper 2, and a wet sludge conveying device 3. The wet sludge storage silo 1 and the wet sludge conveying device 3 are connected via the wet sludge feed hopper 2. Wet sludge with a moisture content of 60-90% enters the wet sludge conveying device 3 through the wet sludge feed hopper 2, and then enters the sludge flash drying subsystem through the wet sludge conveying device 3. The wet sludge conveying device 3 is a screw conveyor. One end of the screw conveyor is connected to the outlet of the wet sludge feed hopper 2, and the other end of the screw conveyor is connected to the sludge flash drying subsystem. Specifically, the sludge flash drying subsystem includes a sludge flash drying device 16. The lower side of the outer shell 20 of the sludge flash drying device 16 is tangentially provided with a wet sludge inlet for the wet sludge to enter. The other end of the screw conveyor is connected to the wet sludge inlet.

[0031] like Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, the sludge flash drying subsystem includes a sludge flash drying device 16 and a drive motor 17. An upper bearing 19 is provided on the top surface of the outer casing 20 of the sludge flash drying device 16, and a lower bearing 26 is provided on the bottom surface of the outer casing 20. The upper bearing 19 and the lower bearing 26 are arranged vertically opposite each other. A rotating shaft 18 is vertically arranged, and its top end is connected to the drive motor 17. The drive motor 17 can drive the rotating shaft 18 to rotate. The rotating shaft 18 is connected to both the upper bearing 19 and the lower bearing 26. The rotating shaft 18 extends from the upper bearing 19 into the interior of the sludge flash drying device 16, and then its bottom end protrudes from the bottom surface of the outer casing 20 to connect to the lower bearing 26. The rotating shaft 18, the upper bearing 19, and the lower bearing 26 are all connected. All bearings 26 are clearance-fitted, and the rotating shaft 18 can rotate around the inner walls of the upper bearing 19 and the lower bearing 26. The drive motor 17 is supported by the rotating shaft 18, the upper bearing 19, the lower bearing 26, and the outer shell 20 of the sludge flash drying device 16. The lower side of the outer shell 20 of the sludge flash drying device 16 is tangentially provided with a wet sludge inlet for wet sludge to enter. The wet sludge inlet is connected to the wet sludge conveying device 3 and is located above the air distribution plate 24. The air distribution plate 24 is located inside the sludge flash drying device 16, and the end of the air distribution plate 24 is connected to the inner wall of the shell of the sludge flash drying device 16. The air distribution plate 24 has evenly arranged holes, which can make the air distribution uniform, thereby improving the drying efficiency of the sludge.

[0032] The lower side of the outer shell 20 of the sludge flash drying device 16 is also tangentially provided with a drying gas inlet 27 for hot flue gas and hot air to enter, and the drying gas inlet 27 is located below the air distribution plate 24. The drying gas serves as the heat source and fluidization medium for drying wet sludge. The wet sludge inlet is located above the drying gas inlet 27, and the wet sludge inlet and the drying gas inlet 27 are located on the same side of the sludge flash drying device 16.

[0033] The upper side of the outer shell 20 of the sludge flash drying device 16 is provided with an outlet 28 for the discharge of small granular dry sludge and exhaust gas. The outlet 28 is connected to the gas-solid separator 14 through a pipe.

[0034] The outer shell 20 of the sludge flash drying device 16 is equipped with a fixing component and a rotating component. The fixing component of the sludge flash drying device 16 includes a limiting plate 21 located above the inner shell 20, an air distribution plate 24 located below the inner shell 20, and several fixed blade holders 22 located inside the outer shell 20 and distributed between the limiting plate 21 and the air distribution plate 24. One end of the fixed blade holder 22 is welded to the inner wall of the shell of the sludge flash drying device 16. The function of the fixed blade holder 22 is to cooperate with the rotating blade 23, and together they break the wet sludge into fine particles by cutting, so that it can be better carried upward by the drying air and improve the drying efficiency.

[0035] The limiting plate 21 can confine the wet sludge within the area where the fixed blade holder 22 and the rotating blade 23 are located, so that the wet sludge can be broken into fine particles by the fixed blade holder 22 and the rotating blade 23.

[0036] The limiting plate 21 has a through hole at its center, the diameter of which is larger than the diameter of the rotating shaft 18. Granular sludge passes through the through hole and reaches the discharge port 28. The air distribution plate 24 has a through hole at its center, the diameter of which is larger than the diameter of the rotating shaft 18. The fixed blade holders 22 gradually decrease in distance from bottom to top, and two fixed blade holders 22 at the same height are symmetrically arranged with respect to the rotating shaft 18. The distance between the top ends of the two fixed blade holders 22 symmetrically arranged with respect to the rotating shaft 18 is larger than the diameter of the rotating shaft 18. The bottom end of each blade holder is fixed to the inner shell of the sludge flash drying device 16. On the wall; the rotating component of the sludge flash drying device 16 includes a plurality of rotating blades 23 and a lift fan 25 disposed inside the outer shell 20 and connected to the rotating shaft 18; one end of the rotating blades 23 is fixedly connected to the rotating shaft 18, and the distance between each pair of rotating blades 23 gradually decreases from bottom to top, the diameter of the rotating blades 23 is smaller than the inner diameter of the outer shell 20, and the rotation of the rotating shaft 18 drives the rotating blades 23 to rotate and cut the sludge; the lift fan 25 is connected to the rotating shaft 18, the rotation of the rotating shaft 18 drives the lift fan 25 to rotate, and the lift fan 25 is disposed below the air distribution plate 24.

[0037] After the wet sludge enters the sludge flash drying device 16, it moves upward and impacts the fixed blade holder 22 under the combined action of the drying gas composed of hot flue gas and hot air, and the auxiliary lift provided by the lift fan 25. The sludge is atomized into fine particles under the combined action of the drying gas, the fixed blade holder 22, and the rotating blades 23, thus increasing the contact area between the fine sludge particles and the drying gas by hundreds or thousands of times. Because the drying gas and the small sludge particles directly contact each other for heat exchange, heat and mass transfer are rapid, resulting in high drying efficiency. The particle size can be controlled by the distribution distance between several fixed cutter holders 22 and rotating cutter blades 23 and the rotation speed of the drive motor 17. The residence time of wet sludge in the sludge flash drying device 16 is 2 to 7 seconds. After the drying process of wet sludge is completed, under the entrainment of the fluidizing medium, the sludge converted into small particles in the sludge flash drying device 16 flows together with the flue gas through the through hole in the center of the limiting disk 21 to the discharge port 28. The small particles of sludge and flue gas flow out from the discharge port 28 and then enter the gas-solid separator 14.

[0038] A gas-solid separator 14 is provided between the sludge flash drying subsystem and the dry sludge conveying subsystem. The gas-solid separator 14 is used to separate the dry sludge and exhaust gas after they have been treated by the sludge flash drying subsystem. The granular dry sludge enters the dry sludge storage silo 15 for storage, and the exhaust gas enters the exhaust gas purification device 13 for treatment to meet the standards before being discharged.

[0039] The gas-solid separator 14 is a first cyclone separator, which can separate solid particles and gas. Small sludge particles and flue gas enter the first cyclone separator. The flue gas is discharged from the gas outlet of the first cyclone separator and enters the tail gas purification device 13. The tail gas purification device 13 is connected to the gas outlet of the first cyclone separator through a pipeline. The small sludge particles are separated by the first cyclone separator and enter the ash hopper of the first cyclone separator.

[0040] The purification device 13 can be a water washing tower, an alkaline washing tower, or a UV photolysis exhaust gas purification device. The flue gas discharged from the first cyclone separator contains ammonia, hydrogen sulfide, etc. Ammonia is soluble in water, and hydrogen sulfide can react chemically with alkaline liquids. Therefore, the flue gas discharged from the first cyclone separator flows into the purification device 13, is purified in the purification device 13, and is then discharged into the atmosphere from the purification device 13.

[0041] Small sludge particles are separated by a cyclone separator and enter the ash hopper of the first cyclone separator. The ash hopper is connected to the dry sludge storage silo 15 through a pipeline. The granular sludge separated from the first cyclone separator, i.e., the gas-solid separator 14, enters the dry sludge storage silo 15.

[0042] The dry sludge conveying subsystem includes a dry sludge storage silo 15, a dry sludge feed hopper 8, and a dry sludge conveying device 9. The dry sludge storage silo 15 and the dry sludge conveying device 9 are connected by the dry sludge feed hopper 8. Dry sludge with a moisture content of 10-30% enters the dry sludge conveying device 9 through the dry sludge feed hopper 8, and then enters the fluidized bed gasifier subsystem through the dry sludge conveying device 9. The dry sludge conveying device 9 is a screw conveyor, one end of which is connected to the dry sludge feed hopper 8, and the other end is connected to the fluidized bed gasifier body 10.

[0043] The fluidized bed gasifier subsystem includes a fluidized bed gasifier body 10, a second cyclone separator 12, and a return feeder 11. The outlet of the fluidized bed gasifier body 10 is connected to the second cyclone separator 12 via a pipeline. The dry sludge entering the fluidized bed gasifier subsystem via the dry sludge conveying device 9 undergoes a gasification reaction in the fluidized bed gasifier body 10, producing a mixture containing fuel gas and flue gas, as well as sludge residue. Subsequently, the mixture containing fuel gas and flue gas, as well as the sludge residue, enter the second cyclone separator 12. The second cyclone separator 12 separates the mixture containing fuel gas and flue gas, as well as the sludge residue, into sludge residue and the mixture containing fuel gas and flue gas.

[0044] The second cyclone separator 12 is connected to the return feeder 11 via a pipeline. The sludge separated by the second cyclone separator 12 enters the return feeder 11 through the connecting pipeline between the second cyclone separator 12 and the return feeder 11. The return feeder 11 is connected to the fluidized bed gasifier body 10 through a pipeline. Therefore, the sludge in the return feeder 11 flows into the fluidized bed gasifier body 10 through the pipeline between the return feeder 11 and the fluidized bed gasifier body 10 to undergo a gasification reaction again, so as to achieve full treatment of sludge. In practical applications, there is an ash hopper at the bottom of the fluidized bed gasifier body 10, which is used to collect the ash generated in the fluidized bed gasifier body. The mixture containing fuel gas and flue gas separated by the second cyclone separator 12 is discharged from the top of the second cyclone separator 12 and enters the gas-to-gas heat exchanger 6.

[0045] The second air compressor 7 is connected to the air-to-air heat exchanger 6, and the second air compressor 7 supplies air into the air-to-air heat exchanger 6. The mixture of fuel gas and flue gas discharged from the upper part of the second cyclone separator 12 passes through the air-to-air heat exchanger 6 and exchanges heat with the air supplied by the second air compressor 7 in the air-to-air heat exchanger 6. The temperature of the fuel gas and flue gas mixture decreases, and the temperature of the air supplied by the second air compressor 7 into the air-to-air heat exchanger 6 increases, becoming hot air. However, in the air-to-air heat exchanger 6, the fuel gas and flue gas mixture and the air supplied by the second air compressor 7 into the air-to-air heat exchanger 6 do not have direct contact. The fuel gas and flue gas mixture and the air supplied by the second air compressor 7 into the air-to-air heat exchanger 6 travel through two separate pipes in the air-to-air heat exchanger 6. The fuel gas and flue gas mixture and the air supplied by the second air compressor 7 into the air-to-air heat exchanger 6 only serve to exchange heat. The outlet of the gas-gas heat exchanger 6, which is a mixture of fuel gas and flue gas, is connected to the external combustion chamber 4 via a connecting pipe; the outlet of the second air compressor 7 on the gas-gas heat exchanger 6, which supplies air into the gas-gas heat exchanger 6, is connected to the dry gas inlet 27 via a connecting pipe; the first air compressor 5 supplies air into the external combustion chamber 4, and the exhaust port of the external combustion chamber 4 is connected to the dry gas inlet 27 via a connecting pipe.

[0046] After exchanging heat in the gas-gas heat exchanger 6, the mixture of fuel gas and flue gas enters the external combustion chamber 4 and is mixed with the air supplied by the first air compressor 5 for combustion. The hot flue gas generated by combustion and the hot air passing through the gas-gas heat exchanger 6 enter the sludge flash drying subsystem through the dry gas inlet 27 and provide heat for the flash drying of wet sludge.

[0047] In this invention, the temperature of the gas and flue gas mixture discharged from the second cyclone separator 12 is 700-800°C. This 700-800°C gas and flue gas mixture passes through the gas-to-gas heat exchanger 6 and then enters the external combustion chamber 4 for combustion. The resulting flue gas has a temperature of 500-600°C and directly enters the sludge flash drying subsystem. The air supplied by the second air compressor 7 to the gas-to-gas heat exchanger 6 has its temperature increased to 200-300°C after passing through the gas-to-gas heat exchanger 6 and then directly enters the sludge flash drying subsystem.

[0048] Finally, it should be noted that the contents not described in detail in this specification belong to the prior art known to those skilled in the art. The above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A sludge flash dewatering system integrated with a fluidized bed gasifier, comprising a wet sludge delivery subsystem, characterized in that: The outlet of the wet sludge conveying subsystem is communicated with the inlet of the sludge flash drying subsystem, the outlet of the sludge flash drying subsystem is connected with the inlet of the gas-solid separator (14), the outlet of the gas-solid separator (14) is communicated with the inlet of the dry sludge conveying subsystem, the outlet of the dry sludge conveying subsystem is communicated with the inlet of the fluidized bed gasification furnace subsystem, the outlet of the fluidized bed gasification furnace subsystem is communicated with the gas-gas heat exchanger (6), the outlet of the gas-gas heat exchanger (6) is communicated with the inlet of the external combustion chamber (4), and the outlet of the external combustion chamber (4) is communicated with the drying gas inlet (27) of the sludge flash drying subsystem; The second air compressor (7) is communicated with the gas-gas heat exchanger (6), the second air compressor (7) conveys air into the gas-gas heat exchanger (6), the temperature of the air conveyed by the second air compressor (7) into the gas-gas heat exchanger (6) is increased to become hot air, and the outlet of the air conveyed by the second air compressor (7) into the gas-gas heat exchanger (6) is communicated with the drying gas inlet (27) through a connecting pipeline; the first air compressor (5) conveys air into the external combustion chamber (4), and the exhaust port of the external combustion chamber (4) is communicated with the drying gas inlet (27) through a connecting pipeline; The sludge flash drying subsystem comprises a sludge flash drying device (16) and a driving motor (17), and the top end of the rotating shaft (18) is connected with the driving motor (17); the sludge flash drying device (16) is internally provided with a fixed part and a rotating part; the fixed part comprises a limiting disc (21) arranged at the upper part inside the sludge flash drying device (16), a wind distribution plate (24) arranged at the lower part inside the sludge flash drying device (16), and a plurality of fixed knife holders (22) arranged between the limiting disc (21) and the wind distribution plate (24), one end of the fixed knife holder (22) is connected to the inner wall of the shell of the sludge flash drying device (16), the distance between the fixed knife holders (22) gradually decreases from bottom to top and between each other, the rotating part comprises a plurality of rotating knife leaves (23) and a lift fan (25) arranged inside the sludge flash drying device (16) and connected with the rotating shaft (18); one end of the rotating knife leaf (23) is fixedly connected with the rotating shaft (18), and the distance between the plurality of rotating knife leaves (23) gradually decreases from bottom to top and between each other, the lift fan (25) is arranged below the wind distribution plate (24), and the drying gas inlet (27) is arranged below the wind distribution plate (24).

2. The sludge flash dewatering system of integrated fluidized bed gasifier according to claim 1, characterized in that: The wet sludge conveying subsystem comprises a wet sludge storage bin (1), a wet sludge feeding hopper (2) and a wet sludge conveying device (3), the wet sludge feeding hopper (2) is connected with the wet sludge storage bin (1) and the wet sludge conveying device (3); the wet sludge conveying device (3) is a screw conveying device, one end of the screw conveying device is communicated with the outlet of the wet sludge feeding hopper (2), and the other end of the screw conveying device is communicated with the sludge flash drying subsystem.

3. The sludge flash dewatering system of integrated fluidized bed gasifier according to claim 1, characterized in that: The upper bearing (19) is arranged on the top surface of the outer shell (20) of the sludge flash drying device (16), and the lower bearing (19) is arranged on the bottom surface of the outer shell (20) of the sludge flash drying device (16); the upper bearing (19) and the lower bearing (26) are arranged in an up-down array; the driving motor (17) can drive the rotating shaft (18) to rotate; the rotating shaft (18) is connected with the upper bearing (19) and the lower bearing (26); the rotating shaft (18) is in clearance fit with the upper bearing (19) and the lower bearing (26), and the rotating shaft (18) can rotate around the inner walls of the upper bearing (19) and the lower bearing (26).

4. The sludge flash dewatering system of an integrated fluidized bed gasifier according to claim 3, characterized in that: The lower side of the outer shell (20) of the sludge flash drying device (16) is provided with a wet sludge inlet and a drying gas inlet (27) for the entry of wet sludge; the wet sludge inlet is located above the drying gas inlet (27); the wet sludge inlet and the drying gas inlet (27) are located on the same side of the sludge flash drying device (16). The wet sludge inlet is connected with the wet sludge conveying device (3); the wet sludge inlet is arranged above the air distribution plate (24) located in the sludge flash drying device (16); the end of the air distribution plate (24) is connected with the inner wall of the shell of the sludge flash drying device (16); and the air distribution plate (24) is provided with uniformly arranged holes. The upper side of the outer shell (20) of the sludge flash drying device (16) is provided with a discharge port (28) for the discharge of granular dry sludge and tail gas; the discharge port (28) is connected with the gas-solid separator (14) through a pipeline.

5. The sludge flash dewatering system of an integrated fluidized bed gasifier according to claim 4, characterized in that: The end of the limiting disc (21) is connected with the inner wall of the shell of the sludge flash drying device (16); the center of the limiting disc (21) is provided with a through hole; the diameter of the through hole of the limiting disc (21) is greater than the diameter of the rotating shaft (18); the middle part of the air distribution plate (24) is provided with a through hole; the diameter of the through hole of the middle part of the air distribution plate (24) is greater than the diameter of the rotating shaft (18); the two fixed knife holders (22) arranged at the same height are symmetrically arranged relative to the rotating shaft (18); the distance between the top ends of the two fixed knife holders (22) symmetrically arranged relative to the rotating shaft (18) is greater than the diameter of the rotating shaft (18). One end of the rotating blade (23) is fixedly connected with the rotating shaft (18); the diameter of the rotating blade (23) is less than the inner diameter of the outer shell (20); the lifting fan (25) is connected with the rotating shaft (18); the rotating shaft (18) drives the lifting fan (25) to rotate.

6. The sludge flash dewatering system of integrated fluidized bed gasifier according to claim 1, characterized in that: The gas-solid separator (14) is a first cyclone separator; the gas discharge port of the first cyclone separator is communicated with the tail gas purification device (13) through a pipeline; the purification device (13) is a water washing tower or an alkali washing tower or a UV photolysis waste gas purification equipment; the bottom outlet of the first cyclone separator is communicated with the dry sludge storage bin (15) through a pipeline.

7. The sludge flash dewatering system of integrated fluidized bed gasifier according to claim 1, characterized in that: The dry sludge conveying subsystem comprises a dry sludge storage bin (15), a dry sludge feeding hopper (8) and a dry sludge conveying device (9), the dry sludge storage bin (15) is connected with the dry sludge conveying device (9) through the dry sludge feeding hopper (8), the dry sludge conveying device (9) is a screw conveying device, one end of the screw conveying device is communicated with the dry sludge feeding hopper (8), and the other end is communicated with the fluidized bed gasification furnace body (10).

8. The sludge flash dewatering system of integrated fluidized bed gasifier according to claim 1, characterized in that: The fluidized bed gasification furnace subsystem comprises a fluidized bed gasification furnace body (10), a second cyclone separator (12) and a return feeder (11); the outlet of the fluidized bed gasification furnace body (10) is communicated with the second cyclone separator (12) through a pipeline; the bottom outlet of the second cyclone separator (12) is communicated with the inlet of the return feeder (11) through a pipeline, the outlet of the return feeder (11) is communicated with the fluidized bed gasification furnace body (10) through a pipeline; the gas exhaust outlet of the upper portion of the second cyclone separator (12) is communicated with the gas-gas heat exchanger (6) through a pipeline.

9. The sludge flash dewatering system of integrated fluidized bed gasifier according to claim 1, characterized in that: The gas-gas heat exchanger (6) is communicated with the second air compressor (7), the gas-gas heat exchanger (6) is communicated with the outer combustion chamber (4) through a connecting pipeline at the gas and flue gas mixture exhaust outlet of the gas-gas heat exchanger (6); the air conveying outlet of the second air compressor (7) to the gas-gas heat exchanger (6) of the gas-gas heat exchanger (6) is communicated with the dry gas inlet (27) through a connecting pipeline; the first air compressor (5) conveys air to the outer combustion chamber (4), and the exhaust port of the outer combustion chamber (4) is communicated with the dry gas inlet (27) through a connecting pipeline.

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