Entrained-flow bed gasification furnace

Abstract

The invention provides an entrained-flow bed gasification furnace. The entrained-flow bed gasification furnace comprises a gasification chamber, a solid-gas separation device and a radiation waste heat boiler, the solid-gas separation device is provided with a gas inlet and a gas outlet, the gas inlet of the solid-gas separation device is connected with the gasification chamber, and the gas outlet of the solid-gas separation device is connected with the radiation waste heat boiler. According to the entrained-flow bed gasification furnace, synthesis gas in the gasification chamber firstly enters the solid-gas separation device, the synthesis gas is separated from ash in the solid-gas separation device through the solid-gas separation device to purify the synthesis gas, the purified synthesis gas enters the radiation waste heat boiler to recover heat, and the ash can be prevented from entering and being attached to the radiation waste heat boiler to affect the heat recovery effect.

Description

Technical Field

[0001] This invention relates to the field of gasification, and more specifically to a fluidized bed gasifier. Background Technology

[0002] In related technologies, a gasifier includes a gasification chamber and a radiant waste boiler. Carbon-based raw materials, such as pulverized coal, are mixed with a gasifying agent and undergo combustion and gasification reactions in the gasification chamber. The resulting syngas enters the radiant waste boiler to recover heat. However, because the syngas contains ash, including molten coarse slag and solid fine slag, the ash adheres to the radiant waste boiler after it enters, reducing the heat recovery efficiency of the boiler. Summary of the Invention

[0003] The present invention aims to at least partially solve one of the technical problems in the related art.

[0004] Therefore, embodiments of the present invention propose an airflow gasifier.

[0005] The fluidized bed gasifier of this invention includes: The system includes a gasification chamber, a solid-gas separation device, and a radiation waste pot. The solid-gas separation device has an air inlet and an air outlet. The air inlet of the solid-gas separation device is connected to the gasification chamber, and the air outlet of the solid-gas separation device is connected to the radiation waste pot.

[0006] In the fluidized bed gasifier of this invention, the syngas in the gasification chamber first enters the solid-gas separation device, which separates the syngas from the ash and slag inside to purify the syngas. The purified syngas then enters the radiant waste boiler to recover heat, which can prevent ash and slag from entering and adhering to the radiant waste boiler and affecting the heat recovery effect.

[0007] In some embodiments, the solid-gas separation device includes a cyclone separator, which has the air inlet and the exhaust outlet.

[0008] In some embodiments, the solid-gas separation device further includes a gasification element, the gasification element having a gasification agent outlet, the cyclone separator having a slag discharge port, the gasification element being located at the slag discharge port, and the gasification agent outlet being connected to the slag discharge port.

[0009] In some embodiments, the gasifying element is an annular ring surrounding a slag discharge channel, the axial direction of the gasifying element is parallel to the centerline of the slag discharge port, the slag discharge channel is used for the slag discharge of the cyclone separator, thereby discharging the slag out of the slag discharge port, and the gasifying element has a gasifying agent outlet on its inner circumferential side surrounding the slag discharge channel.

[0010] In some embodiments, the vaporizing agent outlets are spaced in multiple intervals along the circumferential direction of the vaporizing element; and / or The diameter of the gasifying agent outlet is 0.1 mm to 2 mm.

[0011] In some embodiments, the diameter of the slag discharge channel is 50mm to 200mm; and / or The apparent gas velocity of the medium in the slag discharge channel is 5 m / s to 15 m / s.

[0012] In some embodiments, the gasifying element is provided as one, which is connected to the inner circumferential surface of the slag discharge port or embedded in the wall of the slag discharge port and extends circumferentially along the slag discharge port.

[0013] In some embodiments, at least two gasifying elements are provided, and the at least two gasifying elements are arranged in the slag discharge port along the cross-sectional direction of the slag discharge port. A portion of each gasifying element is connected to the inner circumferential surface of the slag discharge port or embedded in the wall of the slag discharge port, and the space between adjacent gasifying elements and the inner circumferential surface of the slag discharge port is closed.

[0014] In some embodiments, the gasifying element includes an inner ring and an outer ring. The outer ring is disposed outside the inner ring and connected between the slag discharge port and the inner ring. The inner ring has an inner ring cavity and a gasifying agent outlet. The gasifying agent outlet communicates with the inner ring cavity. The inner ring cavity is used for the flow of gasifying agent and for supplying it to the gasifying agent outlet. The outer ring has an outer ring cavity for the flow of coolant.

[0015] In some embodiments, the outer ring surrounds the outer side of the inner ring, and on the cross-section of the vaporizing element, the outer ring surrounds the inner ring circumferentially at 270° to 330° to form an annular notch, and the portion of the inner ring opposite to the notch is provided with the vaporizing agent outlet.

[0016] In some embodiments, the fluidized bed gasifier further includes a quench chamber, and the solid-gas separation device is further provided with a slag discharge port, which is connected to the quench chamber. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of an airflow gasifier according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the gasification component of the fluidized bed gasifier according to an embodiment of the present invention; Figure 3 This is a cross-sectional view of the gasification component of the fluidized bed gasifier according to an embodiment of the present invention; Figure 4 This is a first installation schematic diagram of the gasification component of the fluidized bed gasifier according to an embodiment of the present invention; Figure 5 This is a second installation schematic diagram of the gasification component of the fluidized bed gasifier according to an embodiment of the present invention; Figure 6 This is a third installation schematic diagram of the gasification component of the fluidized bed gasifier according to an embodiment of the present invention.

[0018] Figure label: 1. Gasification chamber; 2. Solid-gas separation device; 21. Air inlet; 22. Exhaust outlet; 23. Cyclone separator; 231. Cylindrical section; 232. Conical section; 24. Gasification component; 241. Gasification agent outlet; 242. Slag discharge channel; 243. Inner ring; 244. Outer ring; 245. Inner ring cavity; 246. Outer ring cavity; 247. Notch; 248. Interface; 25. Slag discharge port; 3. Radiant waste boiler; 4. Quenching chamber. Detailed Implementation

[0019] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0020] The following is for reference. Figures 1-6 A fluidized bed gasifier according to an embodiment of the present invention is described.

[0021] like Figures 1-6 As shown, the fluidized bed gasifier of this embodiment of the invention includes a gasification chamber 1, a solid-gas separation device 2, and a radiant waste boiler 3.

[0022] The solid-gas separation device 2 is equipped with an air inlet 21 and an exhaust outlet 22. The air inlet 21 of the solid-gas separation device 2 is connected to the gasification chamber 1, and the exhaust outlet 22 of the solid-gas separation device 2 is connected to the radiant waste cooker 3. Figure 1 As shown.

[0023] In the fluidized bed gasifier of this invention, the syngas in the gasification chamber 1 first enters the solid-gas separation device 2, which separates the syngas from the ash and slag inside to purify the syngas. The purified syngas then enters the radiant waste boiler 3 to recover heat, which can prevent ash and slag from entering and adhering to the radiant waste boiler 3 and affecting the heat recovery effect.

[0024] In some embodiments, such as Figure 1As shown, the solid-gas separation device 2 includes a cyclone separator 23, which has an air inlet 21 and an exhaust port 22. The syngas from the gasification chamber 1 enters the cyclone separator 23 through the air inlet 21 and generates centrifugal force. The ash carried inside the syngas includes molten coarse ash and solid fine ash. Due to its higher density, the molten coarse ash separates from the syngas under centrifugal force and is thrown onto the inner wall of the cyclone separator 23. At the same time, due to the stickiness of the molten coarse ash, it can capture the less dense solid fine ash, so that the solid fine ash adheres to the inner wall of the cyclone separator 23. Thus, under the action of centrifugal force, the ash is separated from the syngas, achieving the purification of the syngas.

[0025] In some embodiments, such as Figure 1 and Figure 2 As shown, the solid-gas separation device 2 also includes a gasification element 24, which has a gasification agent outlet 241. The cyclone separator 23 has a slag discharge port 25. The gasification element 24 is located at the slag discharge port 25, and the gasification agent outlet 241 is connected to the slag discharge port 25.

[0026] In the cyclone separator 23, the ash separated from the syngas is thrown onto the inner wall of the cyclone separator 23 and flows downward along the inner wall of the cyclone separator 23 to the slag discharge port 25 under the action of gravity. The gasification element 24 located at the slag discharge port 25 releases gasification agent through the gasification agent outlet 241 to melt and gasify the ash, and further generate syngas and sensible heat, so that the radiant waste boiler 3 can recover more heat.

[0027] The gasifying agent released at the gasifying agent outlet 241 also has a lifting effect on the ash slag. The ash slag that has not been melted and gasified has low density, high viscosity and poor fluidity. Under the lifting effect, it can stay at the slag discharge port 25, so that the gasifying agent can fully convert the carbon in the ash slag, thereby improving the carbon conversion rate. The ash slag after melting and gasification has high density, low viscosity and good fluidity. The lifting effect of the gasifying agent cannot make the ash slag after melting and gasification stay, so the ash slag after melting and gasification is discharged from the slag discharge port 25.

[0028] The vaporizing agent is preferably, but not limited to, a mixture of oxygen and water vapor.

[0029] In some embodiments, the cyclone separator 23 includes a cylindrical section 231 and a conical section 232. An air inlet 21 and an exhaust outlet 22 are disposed on the cylindrical section 231. The conical section 232 is connected between the cylindrical section 231 and the slag discharge outlet 25. The cross-sectional area of ​​the conical section 232 decreases from the cylindrical section 231 to the slag discharge outlet 25. The inclination angle α of the conical section 232 is 10° to 45°.

[0030] like Figure 1As shown, cylindrical section 231 and conical section 232 are arranged sequentially from top to bottom. The cross-sectional area of ​​cylindrical section 231 is constant along the vertical direction, while the cross-sectional area of ​​conical section 232 decreases from top to bottom. Air inlet 21 and exhaust outlet 22 are located at the top of cylindrical section 231, and slag discharge outlet 25 is located at the bottom of conical section 232. Slag discharge outlet 25 is preferably, but not limited to, extending vertically to facilitate the installation of gasification component 24 and to form a lifting effect, while also facilitating the discharge of ash and slag. The cross-sectional area of ​​slag discharge outlet 25 is preferably, but not limited to, consistent with the minimum cross-sectional area of ​​conical section 232, so that ash and slag can flow from the inner wall of conical section 232 to the inner wall of slag discharge outlet 25.

[0031] In the longitudinal section of the cyclone separator 23, the angle α between the extension direction of the wall of the conical section 232 and the vertical direction is 10° to 45°, for example, 10°, 30°, 45°, to facilitate the flow of ash and slag.

[0032] In some embodiments, the gasification temperature generated by the gasification element 24 is 100°C to 300°C higher than the gasification temperature of the gasification chamber 1, for example, 100°C, 200°C, or 300°C, so as to be able to melt and gasify the ash.

[0033] In some embodiments, such as Figure 1 and Figure 2 As shown, the gasifying element 24 is annular, surrounding the slag discharge channel 242; in other words, the annular gasifying element 24 surrounds the slag discharge channel 242. The axial direction of the gasifying element 24 is parallel to the centerline of the slag discharge port 25 (e.g., ...). Figure 1 Parallel to the vertical direction shown, the slag discharge channel 242 is used for the slag discharge of the cyclone separator 23, so that the slag is discharged from the slag discharge port 25. The gasification component 24 is provided with a gasification agent outlet 241 around the inner circumference of the slag discharge channel 242, so that the gasification agent discharged from the gasification agent outlet 241 can lift the ash and slag passing through the slag discharge channel 242 and react fully with the ash and slag to melt and gasify the ash and slag.

[0034] It is understood that the gasifying element 24 is not limited to being ring-shaped. In other embodiments, the gasifying element 24 is spherical or circular. The gasifying element 24 is connected or suspended at the center of the cross-section of the slag discharge port 25 by a bracket. The outer peripheral surface of the gasifying element 24 is provided with a gasifying agent outlet 241. Ash and slag pass between the outer peripheral surface of the gasifying element 24 and the inner peripheral surface of the slag discharge port 25.

[0035] In some embodiments, the gasifying agent outlets 241 are arranged in multiple circumferentially along the gasifying member 24, so that the gasifying agent discharged from the gasifying agent outlets 241 is distributed circumferentially along the gasifying member 24, thereby lifting the ash and reacting fully with the ash to melt and gasify the ash.

[0036] In some embodiments, the diameter of the gasifying agent outlet 241 is 0.1 mm to 2 mm, for example, 0.1 mm, 1 mm, or 2 mm, so that the gasifying agent discharged from the gasifying agent outlet 241 has a high pressure and velocity, thereby enabling it to lift the ash and slag.

[0037] In some embodiments, the diameter of the slag discharge channel 242 is 50mm to 200mm, for example 50mm, 120mm, or 200mm, so that the ash can be lifted and held when passing through the slag discharge channel 242.

[0038] In some embodiments, the apparent gas velocity of the medium in the slag discharge channel 242 is 5 m / s to 15 m / s, for example, 5 m / s, 10 m / s, or 15 m / s, so that the ash can be lifted and held when passing through the slag discharge channel 242.

[0039] In some embodiments, such as Figure 2 As shown, the vaporizing element 24 includes an inner ring 243 and an outer ring 244. Both the inner ring 243 and the outer ring 244 are annular in the vertical direction. The outer ring 244 is located outside the inner ring 243. The outer ring 244 can be arranged side by side with the inner ring 243 along the radial direction of the vaporizing element 24, or it can surround the outer side of the inner ring 243.

[0040] like Figures 3-5 As shown, the outer ring 244 is connected between the slag discharge port 25 and the inner ring 243. The outer ring 244 can be connected to the inner circumferential surface of the slag discharge port 25 or embedded in the wall of the slag discharge port 25.

[0041] The inner ring 243 is provided with an inner ring cavity 245 and a vaporizing agent outlet 241. The vaporizing agent outlet 241 is connected to the inner ring cavity 245, and the inner ring cavity 245 is used for the flow of vaporizing agent and for supplying it to the vaporizing agent outlet 241. For example... Figure 2 and Figure 3 As shown, the inner annular cavity 245 is an annular ring extending circumferentially (around the vertical direction) along the inner ring 243. The vaporizing agent outlet 241 can be configured as one row or at least two rows spaced apart, preferably two rows. Each row includes a plurality of vaporizing agent outlets 241 spaced apart circumferentially along the inner ring 243. The vaporizing agent enters the inner annular cavity 245 and flows, and is then supplied to each vaporizing agent outlet 241.

[0042] The outer ring 244 has an outer annular cavity 246, which is used for coolant flow. For example... Figure 2 and Figure 3 As shown, the outer annular cavity 246 is an annular ring extending circumferentially (around the vertical direction) along the outer ring 244. The coolant flows along the outer annular cavity 246 and cools the outer ring 244 and inner ring 243 to prevent the vaporization component 24 from being damaged due to excessively high ambient temperature and ash temperature. The coolant is preferably, but not limited to, cooling water.

[0043] Furthermore, such as Figures 4-6 As shown, the vaporizing component 24 is provided with an interface 248. The interface 248 may be provided with channels that communicate with the inner ring cavity 245 and the outer ring cavity 246 respectively, or it may be configured as multiple channels that communicate with the inner ring cavity 245 and the outer ring cavity 246 respectively. Vaporizing agent is supplied to the inner ring cavity 245, coolant is supplied to the outer ring cavity 246, and coolant is discharged into the outer ring cavity 246 through the interface 248.

[0044] In some embodiments, the outer ring 244 surrounds the outer side of the inner ring 243, and on the cross-section of the vaporizing element 24, the outer ring 244 surrounds the inner ring 243 circumferentially by 270° to 330° to form an annular notch 247, and the portion of the inner ring 243 opposite to the notch 247 is provided with a vaporizing agent outlet 241.

[0045] like Figure 3 As shown, in the cross-section of the vaporizing element 24, the inner ring 243 has a circular cross-section, and the transverse base surface of the outer ring 244 is an arc shape surrounding the outer periphery of the cross-section of the inner ring 243, forming a notch 247. Since the outer ring 244 is an annular ring around the vertical direction, the notch 247 is an arc shape around the vertical direction. The inner cavity of the inner ring 243, with its circular cross-section, forms an inner annular cavity 245. An outer annular cavity 246, with an arc-shaped cross-section, is formed between the inner ring 243 and the outer ring 244.

[0046] The gasifying agent outlet 241 is located on the portion of the inner ring 243 opposite to the gap 247. In other words, the gasifying agent outlet 241 is located on the portion of the inner ring 243 exposed relative to the outer ring 244, so that the gasifying agent outlet 241 can discharge the gasifying agent into the slag discharge port 25.

[0047] On the cross-section of the vaporizing element 24, the transverse base surface of the outer ring 244 extends 270° to 330° around the transverse base surface of the inner ring 243 to ensure the cooling effect on the vaporizing element 24, while giving the inner ring 243 sufficient space to set the vaporizing agent outlet 241.

[0048] In some embodiments, such as Figure 1 As shown, a single gasifying element 24 is configured, which is connected to the inner circumferential surface of the slag discharge port 25 or embedded in the wall of the slag discharge port 25, and extends circumferentially along the slag discharge port 25. Specifically, the outer ring 244 is connected to the inner circumferential surface of the slag discharge port 25 or embedded in the wall of the slag discharge port 25, and extends circumferentially along the slag discharge port 25. The ash and slag in the cyclone separator 23 all pass through the slag discharge channel 242 of the gasifying element 24, and are then discharged from the slag discharge port 25.

[0049] It should be noted that when the ash and slag in the cyclone separator 23 flows to the gasification component 24, it can first flow to the outer ring 244 and then to the inner ring 243, or it can flow directly to the inner ring 243. Since the gasification agent discharged from the gasification agent outlet 241 has a certain pressure and speed, the ash and slag will not block the gasification agent outlet 241.

[0050] In some embodiments, such as Figure 5 and Figure 6 As shown, at least two gasifying elements 24 are provided, preferably but not limited to two or three, and at least two gasifying elements 24 are arranged along the cross-sectional direction of the slag discharge port 25 (e.g., Figure 1 The horizontal plane shown is also the direction orthogonal to the center line of the slag discharge port 25. In other words, at least two gasification elements 24 are arranged in the circumference of the slag discharge port 25.

[0051] Each gasification component 24 is partially connected to or embedded in the inner circumferential surface of the slag discharge port 25. Specifically, the outer ring 244 of each gasification component 24 is partially connected to or embedded in the inner circumferential surface of the slag discharge port 25 to fix the gasification component 24.

[0052] The space between the inner circumferential surfaces of adjacent gasifying elements 24 and slag discharge ports 25 is sealed. Furthermore, when there are at least three gasifying elements 24, the space between all gasifying elements 24 is also sealed, such as... Figure 6 As shown. This ensures that the ash and slag in the cyclone separator 23 must pass through the slag discharge channel 242 during discharge so that they can be melted and gasified by the gasifying agent.

[0053] It should be noted that the number of gasification components 24 is preferably, but not limited to, determined by the inner diameter of the slag discharge port 25 and the diameter of the slag discharge channel 242, so that the diameter of the slag discharge channel 242 can be controlled, thereby allowing the ash and slag to be lifted and held when passing through the slag discharge channel 242.

[0054] In some embodiments, such as Figure 1 As shown, the fluidized bed gasifier also includes a quench chamber 4, and the solid-gas separation device 2 is further provided with a slag discharge port 25, which is connected to the quench chamber 4. The ash slag after being melted and gasified by the gasification component 24 is discharged into the quench chamber 4 through the slag discharge port 25, and then the solidified slag is quenched by the quenching water in the quench chamber 4 to collect the molten and gasified ash slag. The molten and gasified ash slag is quenched into solid glass slag, so as to facilitate the recovery and utilization of the solidified heavy metal ions therein.

[0055] In some embodiments, the gasification chamber 1, the air inlet 21, the exhaust outlet 22 and the quench chamber 4 are provided with at least an inner lining layer, which is formed by any one of refractory bricks, castables, water-cooled walls and jackets, to prevent the pressure-bearing surface from being damaged by ash and slag.

[0056] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0057] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0058] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0059] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0060] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0061] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A fluidized bed gasifier, characterized in that, include: The gasification chamber (1), solid-gas separation device (2) and radiation waste pot (3) are provided. The solid-gas separation device (2) is provided with an air inlet (21) and an exhaust port (22). The air inlet (21) of the solid-gas separation device (2) is connected to the gasification chamber (1), and the exhaust port (22) of the solid-gas separation device (2) is connected to the radiation waste pot (3).

2. The fluidized bed gasifier according to claim 1, characterized in that, The solid-gas separation device (2) includes a cyclone separator (23), which is provided with an air inlet (21) and an exhaust outlet (22).

3. The fluidized bed gasifier according to claim 2, characterized in that, The solid-gas separation device (2) further includes a gasification element (24), which is provided with a gasification agent outlet (241). The cyclone separator (23) is provided with a slag discharge port (25). The gasification element (24) is located at the slag discharge port (25), and the gasification agent outlet (241) is connected to the slag discharge port (25).

4. The fluidized bed gasifier according to claim 2, characterized in that, The gasifying element (24) is an annular ring surrounding the slag discharge channel (242). The axial direction of the gasifying element (24) is parallel to the center line of the slag discharge port (25). The slag discharge channel (242) is used for the slag discharge of the cyclone separator (23), thereby discharging the slag out of the slag discharge port (25). The gasifying element (24) has the gasifying agent outlet (241) on the inner circumference side surrounding the slag discharge channel (242).

5. The fluidized bed gasifier according to claim 4, characterized in that, The gasifying agent outlets (241) are provided in multiple circumferentially spaced locations along the gasifying element (24); and / or The diameter of the gasifying agent outlet (241) is 0.1 mm to 2 mm.

6. The fluidized bed gasifier according to claim 4, characterized in that, The diameter of the slag discharge channel (242) is 50mm to 200mm; and / or The apparent gas velocity of the medium in the slag discharge channel (242) is 5 m / s to 15 m / s.

7. The fluidized bed gasifier according to claim 4, characterized in that, The gasifying element (24) is configured as one unit, which is connected to the inner circumferential surface of the slag discharge port (25) or embedded in the wall of the slag discharge port (25) and extends circumferentially along the slag discharge port (25); or The gasifying element (24) is configured as at least two, and at least two gasifying elements (24) are arranged in the slag discharge port (25) along the cross-sectional direction of the slag discharge port (25). A portion of each gasifying element (24) is connected to the inner circumferential surface of the slag discharge port (25) or embedded in the wall of the slag discharge port (25). The space between adjacent gasifying elements (24) and the inner circumferential surface of the slag discharge port (25) is closed.

8. The fluidized bed gasifier according to any one of claims 4-7, characterized in that, The gasification component (24) includes an inner ring (243) and an outer ring (244). The outer ring (244) is located outside the inner ring (243) and is connected between the slag discharge port (25) and the inner ring (243). The inner ring (243) has an inner ring cavity (245) and a gasification agent outlet (241). The gasification agent outlet (241) is connected to the inner ring cavity (245). The inner ring cavity (245) is used for the flow of gasification agent and supply to the gasification agent outlet (241). The outer ring (244) has an outer ring cavity (246) for the flow of coolant.

9. The fluidized bed gasifier according to claim 8, characterized in that, The outer ring (244) surrounds the outer side of the inner ring (243), and on the cross-section of the vaporizing element (24), the outer ring (244) surrounds the inner ring (243) circumferentially at 270° to 330° to form an annular notch (247), and the portion of the inner ring (243) opposite to the notch (247) is provided with the vaporizing agent outlet (241).

10. The fluidized bed gasifier according to claim 1, characterized in that, It also includes a quench chamber (4), and the solid-gas separation device (2) is also provided with a slag discharge port (25), which is connected to the quench chamber (4).

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