Biomass circulating fluidized bed high-temperature ash slag discharging system

Abstract

The utility model discloses a high-temperature ash slag discharging system of a biomass circulating fluidized bed, which comprises a plurality of groups of slag discharging units connected to a slag discharging port of a gasification furnace. Each group of slag discharging units is provided with a main slag discharging pipeline which is connected to the slag discharging opening; a water-cooling jacketed pipe, a water-cooling slag conveying device and a slag cooler are sequentially arranged on the main slag discharging pipeline in the ash conveying direction, a control valve is arranged between the water-cooling jacketed pipe and the water-cooling slag conveying device, a plurality of sealing gas source input points are arranged on the main slag discharging pipeline, and a sealing gas source inputs sealing gas into the slag discharging pipeline through the multiple input points to achieve multi-stage gas sealing. According to the utility model, a plurality of sealing gas source input points are arranged on the main deslagging pipeline to form multi-stage gas locking sealing and perform multi-stage pressure isolation, so that the sealing reliability is high, the positive pressure gasification requirement is met, the problems of pressure fluctuation, gas leakage and slag-bonding blockage are avoided, the pressure in the furnace is ensured to be stable, the gasification stability is ensured, and the service life of the furnace is prolonged. The stability, reliability and efficiency of the system are improved.

Description

Technical Field

[0001] This utility model relates to the field of biomass gasification technology, and in particular to a biomass circulating fluidized bed high-temperature ash and slag discharge system. Background Technology

[0002] Biomass gasification refers to the technology of converting biomass into combustible syngas containing carbon monoxide and hydrogen through thermochemical reactions at high temperatures (usually 800-900℃). The products of biomass gasification can be used as fuel or chemical feedstock. Biomass gasification technology uses circulating fluidized bed gasification devices for conversion, which features low tar content and low pollutant emissions.

[0003] Currently, when biomass circulating fluidized bed gasifiers operate under positive pressure, the following problems arise during the discharge of their high-temperature ash (800-1000℃): the ash discharge pipes are usually sealed with water seals or single-stage airlock devices. Water seals result in significant heat loss during ash discharge and lead to wastewater and steam entrainment. Single-stage airlock devices have insufficient sealing reliability, making it difficult to meet the requirements of positive pressure gasification. This can easily lead to pressure fluctuations, gas leakage, and slagging blockage. Moreover, pressure fluctuations can disrupt the fluidization state, affect the stability of gasification, and reduce the efficiency of the system. Utility Model Content

[0004] This application addresses the shortcomings of existing biomass circulating fluidized bed ash removal systems by providing a rationally structured high-temperature ash removal system for biomass circulating fluidized beds. This system improves sealing reliability, maintains stable furnace pressure, avoids pressure fluctuations and slagging blockage, and enhances the stability, reliability, and efficiency of the system.

[0005] The technical solution adopted in this utility model is as follows:

[0006] A biomass circulating fluidized bed high-temperature ash and slag discharge system includes several sets of ash and slag discharge units connected to the ash and slag discharge port of a gasifier. Each set of ash and slag discharge units is equipped with a main ash and slag discharge pipeline connected to the ash and slag discharge port. Along the ash and slag conveying direction, a water-cooled jacketed pipe, a water-cooled ash conveying device, and a ash cooler are sequentially arranged on the main ash and slag discharge pipeline. A control valve is installed between the water-cooled jacketed pipe and the water-cooled ash conveying device. Multiple sealing gas source input points are set on the main ash and slag discharge pipeline. The sealing gas source introduces sealing gas into the ash and slag discharge pipeline through multiple input points to achieve multi-stage gas sealing.

[0007] As a further improvement to the above technical solution:

[0008] The control valves include manual valves and pneumatic valves. Sealed air source input points are respectively provided on the slag inlet side of the water-cooled jacket pipe, the slag inlet side of the pneumatic valve, and the rotary joint connection of the slag cooler.

[0009] The water-cooled slag conveying device is tilted upwards along the slag conveying direction.

[0010] The tilt angle α of the water-cooled slag conveying device is 15° to 45°.

[0011] The water-cooled jacketed pipe, the water-cooled slag conveying device, and the slag cooler are each equipped with a water-cooled jacket structure. The water-cooled jacket structure is equipped with an inlet pipe and an outlet pipe. Circulating cooling water is sent in through the inlet pipe and flows out through the outlet pipe.

[0012] The first water inlet pipe of the water-cooled jacketed pipe is located on the slag outlet side of the water-cooled jacketed pipe, and the first water outlet pipe is located on the slag inlet side of the water-cooled jacketed pipe. The flow direction of the circulating cooling water is opposite to the slag conveying direction. The spiral cylinder and the spiral joint of the conveying spiral of the water-cooled slag conveying device are respectively equipped with water-cooled jacketed structures. The water inlet pipe of the water-cooled jacketed structure at the spiral joint is located at a low position, and the water outlet pipe is located at a high position. The outer cylinder and the rotary joint of the slag cooler are respectively equipped with water-cooled jacketed structures.

[0013] Several slag discharge ports are opened on the gasifier, and each slag discharge port is connected to a set of slag discharge units; each set of slag discharge units is equipped with an emergency slag discharge pipeline, which is connected to the slag discharge port.

[0014] The bottom section of the gasifier is equipped with a first control unit, and each ash discharge port is equipped with a second control unit. The first control unit detects the pressure difference of the gasifier, and the second control unit detects the ash discharge temperature. The detection signals of the first and second control units are interlocked with the pneumatic valves. When the pressure difference detected by the first control unit is lower than the set value, and / or the temperature detected by the second control unit is higher than the set value, the pneumatic valves are interlocked and closed.

[0015] The slag cooler is equipped with both graphite seals and mechanical seals.

[0016] The slag discharge pipe inside the water-cooled jacketed pipe is made of high-temperature resistant and wear-resistant material; the water-cooled slag conveying device is a spiral slag conveying device, with a conveying spiral inside the spiral cylinder, and a dense material sealing section formed inside the conveying spiral; the slag cooler is a drum slag cooler or a membrane slag cooler; the conveying spiral of the water-cooled slag conveying device is controlled by frequency conversion, and the slag cooler is controlled by the frequency converter of the frequency conversion motor.

[0017] The beneficial effects of this utility model are as follows:

[0018] This invention sets up multiple sealed gas source input points on the main slag discharge pipeline to form a multi-stage airlock seal, which provides multi-stage pressure isolation, ensuring high sealing reliability, meeting the requirements of positive pressure gasification, avoiding problems such as pressure fluctuations, gas leakage, and slag blockage, ensuring stable pressure inside the furnace, ensuring the stability of gasification, and improving the stability, reliability, and efficiency of the system.

[0019] This invention achieves gradual cooling of ash and slag in stages, resulting in better cooling effect, greater energy efficiency and environmental friendliness. It also allows for the recovery and utilization of waste heat in stages, leading to higher system thermal efficiency.

[0020] The water-cooled slag conveying device of this utility model is inclined upward along the slag conveying direction. The ash and slag are conveyed inclined upward in the water-cooled slag conveying device, which forces the conveying screw to push upward, which can avoid ash and slag backflow and slag accumulation, making the slag conveying more continuous and stable, and avoiding slag caking and slag blockage. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of this utility model.

[0022] Figure 2 This is a schematic diagram of the water-cooled slag conveying device.

[0023] Figure 3 This is a schematic diagram of the structure of a slag cooler.

[0024] In the picture:

[0025] 10. Gasifier; 101. Ash discharge port;

[0026] 20. Slag Discharge Unit; 1. Main Slag Discharge Pipeline; 2. Water-Cooled Jacket Pipe; 21. First Water Inlet Pipeline; 22. First Water Outlet Pipeline; 3. Water-Cooled Slag Conveying Device; 31. Spiral Cylinder; 32. Conveying Spiral; 33. Slag Inlet; 34. Slag Outlet; 35. Second Water Inlet Pipeline; 36. Second Water Outlet Pipeline; 37. Third Water Inlet Pipeline; 38. Third Water Outlet Pipeline; 4. Slag Cooler; 41. Ash Inlet; 42. Ash Outlet; 43. Rotary Joint; 44. Fourth Water Inlet Pipeline; 45. Fourth Water Outlet Pipeline; 46. Fifth Water Inlet Pipeline; 47. Fifth Water Outlet Pipeline; 5. Sealing Air Source; 6. Manual Valve; 7. Pneumatic Valve; 8. Emergency Slag Discharge Pipeline;

[0027] 30. First measurement and control unit; 40. Second measurement and control unit. Detailed Implementation

[0028] The specific embodiments of this utility model are described below with reference to the accompanying drawings.

[0029] like Figure 1 As shown, this utility model provides a biomass circulating fluidized bed high-temperature ash and slag discharge system, including several sets of slag discharge units 20 (two sets in this example) set at the bottom of the gasifier 10. Each set of slag discharge units 20 can meet the slag discharge requirements of a single gasifier 10. A single set of slag discharge units 20 can operate independently, or multiple sets of slag discharge units 20 can operate simultaneously, ensuring the continuity and stability of the system operation.

[0030] like Figure 1 As shown, the bottom of the gasifier 10 has several slag discharge ports 101, and each slag discharge port 101 is connected to a set of slag discharge units 20.

[0031] like Figure 1As shown, each ash discharge unit 20 includes a main ash discharge pipeline 1 and an emergency ash discharge pipeline 8 connected to the ash discharge port 101. The main ash discharge pipeline 1 is the main ash discharge channel when the gasifier 10 is operating normally, unloading the ash and slag generated during the operation of the gasifier 10 to the ash conveying equipment, which then sends it to the sealed ash bin. The emergency ash discharge pipeline 8 is the secondary ash discharge channel when the gasifier 10 is shut down for maintenance, unloading the ash and slag generated during maintenance to the ground. Along the ash and slag conveying direction, the main ash discharge pipeline 1 is sequentially equipped with a water-cooled jacket pipe 2, a water-cooled ash conveying device 3, and a ash cooler 4; a manual valve 6 and a pneumatic valve 7 are installed on the pipeline between the water-cooled jacket pipe 2 and the water-cooled ash conveying device 3 in the main ash discharge pipeline 1 to control the connection between the ash discharge and the lower ash cooler device (water-cooled ash conveying device 3 and ash cooler 4).

[0032] like Figure 1 As shown, on the main slag discharge pipeline 1, sealing gas source 5 input points are respectively set on the slag inlet side of the water-cooled jacket pipe 2 and the slag inlet side of the pneumatic valve 7. A sealing gas source 5 input point is also set on the slag inlet side of the slag cooler 4. The sealing gas source 5 inputs inert gases such as nitrogen or CO2 into the slag discharge pipeline through multiple input points as sealing gases, discharging air from the slag discharge pipeline and creating an inert gas environment inside the pipeline to prevent explosion. The multiple sealing gas source 5 input points on the main slag discharge pipeline 1 form a multi-stage airlock seal, providing multi-stage pressure isolation, high sealing reliability, meeting the requirements of positive pressure gasification, avoiding pressure fluctuations, gas leakage, slag blockage, and ensuring stable furnace pressure, stable gasification, and improved system stability, reliability, and efficiency.

[0033] like Figure 1 As shown, the water-cooled jacketed pipe 2 is used to cool high-temperature ash and slag. The slag discharge pipe inside the water-cooled jacketed pipe 2 is made of high-temperature resistant and wear-resistant material, which can withstand long-term scouring by high-temperature ash and slag, resulting in a longer service life. The water-cooled jacketed pipe 2 is equipped with a first water inlet pipe 21 and a first water outlet pipe 22. Circulating cooling water is supplied from the first water inlet pipe 21 and flows out from the first water outlet pipe 22. The first water inlet pipe 21 is located on the slag discharge side of the water-cooled jacketed pipe 2, and the first water outlet pipe 22 is located on the slag inlet side of the water-cooled jacketed pipe 2. The flow direction of the circulating cooling water is opposite to the slag conveying direction, resulting in better cooling effect and higher heat recovery efficiency.

[0034] like Figure 1 , Figure 2As shown, the water-cooled slag conveying device 3 is a spiral slag conveying device with a wear-resistant and high-temperature resistant structure. A conveying spiral 32 is installed inside its spiral cylinder 31. A dense material seal section is formed inside the conveying spiral 32 to prevent gas leakage and enhance the overall sealing of the system. The conveying spiral 32 is frequency-controlled, allowing adjustment of the slag discharge rate via frequency adjustment. The water-cooled slag conveying device 3 has a slag inlet 33 at one end and a slag outlet 34 at the other end. The device is inclined upwards along the slag conveying direction (from the inlet 33 to the outlet 34), with an inclination angle α ranging from 15° to 45°. The ash and slag are conveyed upwards within the water-cooled slag conveying device 3, forcing the conveying spiral 32 upwards. This prevents ash and slag backflow and accumulation, resulting in more continuous and stable slag conveying and avoiding slag caking and blockage. The spiral cylinder 31 and the spiral joint of the conveying spiral 32 of the water-cooled slag conveying device 3 are respectively provided with water-cooled jacket structures. The water-cooled jacket structure of the spiral cylinder 31 is provided with a second water inlet pipe 35 and a second water outlet pipe 36. The water-cooled jacket structure at the spiral joint of the conveying spiral 32 is provided with a third water inlet pipe 37 and a third water outlet pipe 38. The third water inlet pipe 37 is located at a low position and the third water outlet pipe 38 is located at a high position. Circulating cooling water is sent in from the second water inlet pipe 35 / third water inlet pipe 37 and flows out from the second water outlet pipe 36 / third water outlet pipe 38.

[0035] like Figure 1 , Figure 3 As shown, the slag cooler 4 is either a drum slag cooler or a membrane slag cooler, employing a wear-resistant and high-temperature-resistant structure. One end is equipped with a slag inlet 41, and the other end with a slag outlet 42. A sealing air source 5 is installed at the rotary joint 43 of the slag cooler 4. The slag outlet 42 is connected to a slag conveying device, which can be one or more of a slag conveying scraper, belt conveyor, or horizontal slag conveying screw conveyor. The slag cooler 4 is controlled by a frequency converter of a variable frequency motor to adapt to different slag volumes. In addition to the air seal provided by the sealing air source 5, the slag cooler 4 also features a graphite seal and a mechanical seal, forming a multi-seal system of graphite seal + mechanical seal + air seal, ensuring high sealing reliability. The slag cooler 4 adopts a double-layer rubber sleeve structure. The outer cylinder has a water-cooled jacket layer for cooling water, and the interior contains slag conveying screw blades. A fourth water inlet pipe 44 and a fourth water outlet pipe 45 are provided on the slag cooler 4 corresponding to the cooling layer. Circulating cooling water is supplied from the fourth water inlet pipe 44 and flows out from the fourth water outlet pipe 45. The rotary joint 43 of the slag cooler 4 is also equipped with a water-cooled jacket layer for cooling water. The fifth water inlet pipe 46 and the fifth water outlet pipe 47 are installed on the water-cooled jacket layer. The circulating cooling water cools the rotary joint 43 to prevent the joint from overheating.

[0036] The water-cooled jacketed pipe 2, water-cooled slag conveying device 3, and slag cooler 4 achieve progressive cooling of ash and slag, resulting in better cooling effect, greater energy efficiency and environmental friendliness. Waste heat can be recovered and utilized in stages, making the system more thermally efficient.

[0037] like Figure 1As shown, a first control unit 30 is installed at the bottom section of the gasifier 10, and a second control unit 40 is installed on each ash discharge port 101. The first control unit 30 detects the pressure difference of the gasifier 10, and the second control unit 40 detects the ash discharge temperature. The pressure difference signal detected by the first control unit 30 can determine the ash quantity and ash discharge frequency. Based on the pressure difference signal, the ash discharge frequency can be adjusted in time to prevent the ash discharge quantity from being too large or too small, and to prevent blockage of the ash discharge port 101 or gas leakage. The temperature signal detected by the second control unit 40 can determine whether the ash has been discharged. The detection signals of the first control unit 30 and the second control unit 40 are interlocked with the pneumatic valve 7. When the pressure difference detected by the first control unit 30 is lower than the set value, and / or the temperature detected by the second control unit 40 is higher than the set value, the pneumatic valve 7 is interlocked and closed to prevent high-temperature biomass gas from backflowing into the ash discharge pipe and the ash cooling equipment.

[0038] In actual use, during normal operation of a circulating fluidized bed biomass gasification device, the temperature of the ash at the bottom of the gasifier 10 is about 900°C. The ash enters the ash discharge unit 20 from the ash discharge port 101, passes through the water-cooled jacket pipe 2, the manual valve 6, and the pneumatic valve 7 in sequence, and then enters the inclined water-cooled ash conveying device 3 to cool and form a material seal. After being cooled to 700-750°C by the water-cooled ash conveying device 3, it enters the ash cooler 4. The ash cooler 4 cools the high-temperature ash to below 100°C, and then sends it into the sealed ash bin through the ash conveying equipment.

[0039] The above description is an explanation of the present utility model and not a limitation thereof. The present utility model can be modified in any form without departing from its spirit.

Claims

1. A biomass circulating fluidized bed high-temperature ash slag discharge system comprising a plurality of groups of slag discharge units (20), characterized in that: The slag discharge unit (20) is connected to the slag discharge port (101) of the gasifier (10); each slag discharge unit (20) is equipped with a main slag discharge pipeline (1), which is connected to the slag discharge port (101); the main slag discharge pipeline (1) is equipped with a water-cooled jacket pipe (2), a water-cooled slag conveying device (3), and a slag cooler (4) in sequence along the ash conveying direction; a control valve is provided between the water-cooled jacket pipe (2) and the water-cooled slag conveying device (3); multiple sealing gas source (5) input points are provided on the main slag discharge pipeline (1); the sealing gas source (5) inputs sealing gas into the slag discharge pipeline through multiple input points to achieve multi-stage gas sealing.

2. The biomass circulating fluidized bed high-temperature ash and slag discharge system according to claim 1, characterized in that: The control valves include manual valves (6) and pneumatic valves (7). Sealed air source (5) input points are respectively provided at the slag inlet side of the water-cooled jacket pipe (2), the slag inlet side of the pneumatic valve (7), and the rotary joint (43) connection of the slag cooler (4).

3. The biomass circulating fluidized bed high-temperature ash and slag discharge system according to claim 1, characterized in that: The water-cooled slag conveying device (3) is inclined upward along the slag conveying direction.

4. The biomass circulating fluidized bed high-temperature ash and slag discharge system according to claim 3, characterized in that: The tilt angle α of the water-cooled slag conveying device (3) is 15° to 45°.

5. The biomass circulating fluidized bed high-temperature ash and slag discharge system according to claim 1, characterized in that: Water-cooled jacketed pipe (2), water-cooled slag conveying device (3), and slag cooler (4) are respectively equipped with water-cooled jacketed structures. Water-cooled jacketed structures are equipped with inlet pipes and outlet pipes. Circulating cooling water is sent in from the inlet pipe and flows out from the outlet pipe.

6. The biomass circulating fluidized bed high-temperature ash and slag discharge system according to claim 5, characterized in that: The first water inlet pipe (21) of the water-cooled jacket pipe (2) is set on the slag outlet side of the water-cooled jacket pipe (2), and the first water outlet pipe (22) is set on the slag inlet side of the water-cooled jacket pipe (2). The flow direction of the circulating cooling water is opposite to the slag conveying direction. The spiral cylinder (31) and the spiral joint of the conveying spiral (32) of the water-cooled slag conveying device (3) are respectively equipped with water-cooled jacket structures. The water inlet pipe of the water-cooled jacket structure at the spiral joint is located at a low position and the water outlet pipe is located at a high position. The outer cylinder and the rotary joint (43) of the slag cooler (4) are respectively equipped with water-cooled jacket structures.

7. The high temperature biomass circulating fluidized bed ash and slag discharge system according to claim 1, characterized in that: A number of slag discharge ports (101) are opened on the gasifier (10), and each slag discharge port (101) is connected to a set of slag discharge units (20); each set of slag discharge units (20) is equipped with an emergency slag discharge pipeline (8), which is connected to the slag discharge port (101).

8. The high temperature biomass circulating fluidized bed ash and slag discharge system according to claim 1, characterized in that: A first control unit (30) is provided at the bottom section of the gasifier (10), and a second control unit (40) is provided on each slag discharge port (101). The first control unit (30) detects the pressure difference of the gasifier (10), and the second control unit (40) detects the slag discharge temperature. The detection signals of the first control unit (30) and the second control unit (40) are interlocked with the pneumatic valve (7). When the pressure difference detected by the first control unit (30) is lower than the set value, and / or the temperature detected by the second control unit (40) is higher than the set value, the pneumatic valve (7) is interlocked and closed.

9. The high temperature biomass circulating fluidized bed ash and slag discharge system according to claim 1, characterized in that: The slag cooler (4) is equipped with a graphite seal and a mechanical seal.

10. The biomass circulating fluidized bed high-temperature ash and slag discharge system according to claim 9, characterized in that: The slag discharge pipe inside the water-cooled jacket pipe (2) is made of high temperature and wear-resistant material; the water-cooled slag conveying device (3) is a spiral slag conveying device, and a conveying spiral (32) is set inside the spiral cylinder (31), and a dense material sealing section is formed inside the conveying spiral (32); the slag cooler (4) is a drum slag cooler or a membrane slag cooler; the conveying spiral (32) of the water-cooled slag conveying device (3) is controlled by frequency conversion, and the slag cooler (4) is controlled by the frequency converter of the frequency conversion motor.

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