Fluidized bed gasification furnace

Abstract

The fluidized bed gasifier comprises a gasifier body, a cyclone separator and a material return pipe, the gasifier body comprises a shell, an ash outlet is formed in the bottom of the shell, a fluidization distributor is arranged at the position, above the ash outlet, of the shell, and a plurality of gas inlets are formed in the position, between the fluidization distributor and the ash outlet, of the shell; the shell is provided with a biomass inlet above the fluidization distributor, the biomass inlet is connected with the feeding device, the upper end of the shell is connected with the cyclone separator, one end of the material return pipe is connected with the bottom of the cyclone separator, the other end of the material return pipe is connected with the shell and is connected above the fluidization distributor, and a gasifying agent of the fluidized bed gasifier is pure oxygen. Pure oxygen is used as a gasifying agent, the gas inlet is formed below the fluidization distributor, and the pure oxygen entering the gasification furnace is uniformly distributed by the fluidization distributor and then is in contact with biomass, so that the biomass is completely gasified, and ash and slag are prevented from being formed to block an outlet of the gasification furnace.

Description

Technical Field

[0001] The invention relates to the technical field of biomass gasification, and in particular to a fluidized bed gasifier. Background Art

[0002] The fluidized bed gasification furnace mainly utilizes the conical air distributor at the bottom of the furnace body to blow the biomass particles inside the furnace body so that they are suspended in the airflow. The oxygen-enriched air gasifier oxidizes the biomass particles to produce biomass particles for combustion. The oxidation reaction mainly occurs at the bottom of the furnace body. The airflow goes upward, driving the biomass particles to circulate upward, producing combustible gas and semi-coke. The semi-coke returns to the furnace body through the return device for secondary reaction, and the combustible gas is used after dust removal.

[0003] At present, fluidized bed gasifiers use air as the gasifying agent, and the pressure is also normal pressure, which leads to disadvantages such as low temperature, low gasification efficiency, insufficient pyrolysis and gasification of biomass, and high tar content in the synthesis gas. In addition, the fluidized bed gasifier sprays the gasifying agent and the fluidizing agent into the furnace body through a burner. The gas injected into the furnace body through the burner is unevenly distributed, which can easily lead to incomplete biomass gasification or excessive temperature in local areas, forming molten ash and slag to block the outlet of the gasifier.

[0004] At the same time, the fluidized bed gasification furnace in the prior art is in the form of a shell lined with refractory bricks. The ash in the furnace will corrode the refractory bricks, and the gas-solid medium in the coal gasification will penetrate into the gaps in the refractory bricks, causing the refractory bricks to crack, be damaged, or even fall off in large pieces. Local overheating of the gasifier shell poses a huge safety hazard. Summary of the invention

[0005] In order to solve at least one technical problem of the prior art, the present invention provides a fluidized bed gasification furnace.

[0006] To achieve the above-mentioned purpose of the invention, the technical solution adopted by the present invention is: a fluidized bed gasifier, including a gasifier, a cyclone separator and a return pipe, the gasifier including a shell, the bottom of the shell is provided with an ash outlet, the shell is provided with a fluidizing distributor above the ash outlet, the shell is provided with a plurality of gas inlets between the fluidizing distributor and the ash outlet, the shell is provided with a biomass inlet above the fluidizing distributor, the biomass inlet is connected to a feeding device, the upper end of the shell is connected to the cyclone separator, one end of the return pipe is connected to the bottom of the cyclone separator, the other end of the return pipe is connected to the shell and connected to the top of the fluidizing distributor, and the gasifying agent of the fluidized bed gasifier is pure oxygen.

[0007] Furthermore, a lining is provided inside the shell, the shell is made of high-strength heat-resistant alloy, and the lining is made of heat-resistant and heat-insulating material.

[0008] Further, the outer side of the shell, the outer side of the cyclone separator and the outer side of the return pipe are all covered with a jacket, and the gap between the jacket and the shell, the gap between the cyclone separator and the jacket, and the gap between the return pipe and the jacket are all filled with water;

[0009] The fluidizing distributor comprises four layers of distributor plates, and the four layers of the distributor plates are spaced apart and distributed along the height direction of the shell.

[0010] Furthermore, the distributor plate located at the top is provided with a plurality of distribution valves, and the remaining distributor plates are evenly provided with a plurality of air outlets and a plurality of distribution pipes of different sizes.

[0011] Furthermore, the gas inlet includes a plurality of upper air inlets arranged along the circumference of the shell and a plurality of lower air inlets arranged along the circumference of the shell, the plurality of upper air inlets are arranged between the first and second layers of the distributor plates from bottom to top, and the lower air inlets are located below the first layer of the distributor plates.

[0012] Furthermore, a leakage detection device is provided on the top of the shell.

[0013] Furthermore, the cyclone separator has a synthesis gas inlet, a synthesis gas outlet and a solid outlet, the synthesis gas inlet is arranged tangentially to the inner shell of the cyclone separator, and the solid outlet is connected to the return pipe.

[0014] Furthermore, the cross section of the inlet end of the synthesis gas inlet is circular.

[0015] Furthermore, a material return prevention device is installed on the material return pipe;

[0016] The anti-return device is an anti-return valve.

[0017] Furthermore, the anti-return valve includes a lining shell, a pressure shell wrapped outside the lining shell, a ventilation cover arranged in the lining shell, and wind caps uniformly distributed on the periphery of the ventilation cover.

[0018] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0019] The present invention uses pure oxygen as a gasifying agent, and the gas inlet is arranged below the fluidized distributor. The pure oxygen entering the gasifier is evenly distributed by the fluidized distributor and then contacts the biomass, so that the biomass is completely gasified, and the formation of molten ash and slag blocking the outlet of the gasifier is avoided. In addition, a lining made of heat-resistant and heat-insulating material is arranged in the gasifier of the present invention, so that the local overheating of the gasifier shell is avoided, which causes a huge safety hazard.

[0020] At the same time, the outer side of the shell of the gasifier, the outer side of the cyclone separator and the outer side of the return pipe are all covered with jackets in the present invention, so that the temperature distribution in the fluidized bed gasifier is more uniform and the damage caused by temperature difference stress is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of a fluidized bed gasifier of the present invention.

[0022] Figure 2 A cross-sectional view of a fluidized bed gasifier of the present invention;

[0023] Figure 3 for Figure 2 Sectional view in the AA direction;

[0024] Figure 4 for Figure 2 Cross-sectional view in the BB direction;

[0025] Figure 5 for Figure 2 Cross-sectional view in CC direction;

[0026] Figure 6 It is a cross-sectional view of the anti-return valve of the present invention. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0028] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0029] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings. These terms are mainly used to better describe the present invention and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0030] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those skilled in the art, the specific meanings of these terms in the present invention can be understood according to specific circumstances.

[0031] In addition, the terms "installed", "set", "provided with", "connected", "connected", and "socketed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0033] Reference Figures 1 to 6 The present invention provides a fluidized bed gasifier, including a gasifier 1, a cyclone separator 2 and a return pipe 3. The gasifier 1 includes a shell 11. An ash outlet 16 is provided at the bottom of the shell 11. A fluidizing distributor 4 is provided above the ash outlet 16 of the shell 11. The shell 11 is provided with a plurality of gas inlets 15 between the fluidizing distributor 4 and the ash outlet 16. A biomass inlet 14 is provided above the fluidizing distributor 4 of the shell 11. The biomass inlet 14 is connected to a feeding device. The upper end of the shell 11 is connected to the cyclone separator 2. One end of the return pipe 3 is connected to the bottom of the cyclone separator 2. The other end of the return pipe 3 is connected to the shell and connected above the fluidizing distributor 4.

[0034] The fluidized bed gasifier of the present invention uses pure oxygen as a gasifying agent and carbon dioxide as a fluidizing agent.

[0035] The present invention arranges the gas inlet 15 below the fluidizing distributor 4 so that the gasifying agent and the fluidizing agent enter the gasifier 1 through the gas inlet 15 and need to pass through the fluidizing distributor 4 to contact the biomass located above the fluidizing distributor 4. The fluidizing distributor 4 can evenly distribute the gas above the fluidizing distributor 4, making the gas flow distribution more even, so that the biomass is completely gasified and the formation of molten ash and slag to block the outlet of the gasifier is avoided.

[0036] Furthermore, a lining 12 is provided inside the shell 11. The shell 11 is made of high-strength heat-resistant alloy, and the lining 12 is made of heat-resistant insulation material. The lining 12 made of heat-resistant insulation material can prevent the ash in the furnace from corroding the refractory bricks, and avoid the huge safety hazard caused by the local overheating of the gasification furnace shell.

[0037] Furthermore, the outer side of the shell 11, the outer side of the cyclone separator 2 and the outer side of the return pipe 3 are all covered with a jacket 13, and the gap between the jacket 13 and the shell 11, the gap between the cyclone separator 2 and the jacket 13, and the gap between the return pipe 3 and the jacket are all filled with water. The jacket 13 and the water filled in the jacket 13 can make the temperature distribution in the fluidized bed gasifier more uniform and always within the safe temperature range, reducing the damage caused by temperature difference stress.

[0038] Furthermore, the fluidizing distributor 4 includes four layers of distributor plates 41 , and the four layers of distributor plates 41 are distributed at intervals along the height direction of the shell 11 .

[0039] Furthermore, the distributor plate 41 located at the top is provided with a plurality of distribution valves 42 , and the remaining distributor plates 41 are provided with a plurality of distribution pipes 43 of different sizes, and the remaining distributor plates 41 are evenly distributed with a plurality of air outlets.

[0040] Furthermore, the gas inlet 15 includes a plurality of upper air inlets 151 arranged circumferentially along the shell 11 and a plurality of lower air inlets 152 arranged circumferentially along the shell 11 , the plurality of upper air inlets 151 are arranged between the first and second layers of distributor plates 41 from bottom to top, and the lower air inlets 152 are located below the first layer of distributor plates 41 .

[0041] Preferably, the lower air inlet 152 is arranged to be inclined downward so that the air inlet direction is inclined upward, so that the air flow flows toward the fluidizing distributor 4 .

[0042] Furthermore, a leakage detection device 18 is provided on the top of the shell 11 , and a cover plate 17 is provided at the ash outlet 16 .

[0043] Furthermore, the cyclone separator 2 has a synthesis gas inlet 21 , a synthesis gas outlet 22 and a solid outlet 23 . The synthesis gas inlet 21 is arranged tangentially to the inner shell of the cyclone separator 2 , and the solid outlet 23 is connected to the return pipe 3 .

[0044] Furthermore, the cross section of the inlet end of the synthesis gas inlet 21 is circular, such as Figure 3 As shown. The cross section of the inlet end of the synthesis gas inlet 21 is designed to be circular. Due to its smooth profile and uniform stress distribution characteristics, the circular cross section exhibits better mechanical properties under high pressure conditions, reduces stress concentration, and improves the structural strength and pressure bearing capacity of the equipment, so that the inlet structure can be used stably for a long time under extreme conditions of high temperature (≥1200℃) and high pressure (≥3.0MPa). At the same time, in order to maintain the stability and separation efficiency of the internal flow field of the cyclone separator, the lining part maintains a rectangular structure, as shown. Figure 4 shown.

[0045] Preferably, the inner lining of the syngas inlet 21 is a rectangular gradient structure, that is, the size of the inlet end of the syngas inlet 21 is larger than the size of the outlet end. Since the inlet end of the syngas inlet 21 is appropriately enlarged, in order to minimize the overall size, the inlet end of the syngas inlet 21 also adopts a tangent structure.

[0046] Furthermore, an anti-return device 5 is installed on the return pipe 3 to prevent the solid from flowing back from the gasifier 1 to the cyclone separator 2 .

[0047] Furthermore, the anti-return device 5 is an anti-return valve.

[0048] Furthermore, the anti-return valve includes a lining shell 51, a pressure shell 52 wrapped outside the lining shell 51, a ventilation cover 53 arranged in the lining shell 51, and wind caps 54 evenly distributed on the periphery of the ventilation cover 53, and the ventilation cover 53 is made of high-temperature resistant high-alloy material. The present invention uses the weight of the material itself to form a natural pressure difference, and the wind caps evenly distributed around the periphery ensure the stable circulation of the material. The external pressure shell is designed as a two-stage cone shell structure with folded edges to avoid large stress concentration and withstand higher pressure; at the same time, in order to ensure the smooth and stable circulation of the material, specially designed wind caps 54 are evenly distributed around the ventilation cover. These wind caps 54 not only optimize the airflow distribution, effectively prevent the blockage or accumulation of materials during the circulation process, but also further enhance the overall efficiency and stability of the ventilation structure.

[0049] Preferably, both the lining shell 51 and the pressure shell 52 adopt a two-section structure with a folded cone shell. This structure not only optimizes the mechanical properties of the structure, but also disperses and reduces stress concentration through the geometric shape of the folded cone shell, thereby significantly improving the bearing capacity of the equipment under high pressure conditions; at the same time, this structure also enhances the rigidity and stability of the pressure shell, enabling it to maintain structural integrity and functionality under extreme working conditions.

[0050] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to the above embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without removing the spirit or scope of the present invention. Therefore, the present invention will not be limited to the above embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A fluidized bed gasifier, characterized in that: The invention comprises a gasifier (1), a cyclone separator (2) and a return pipe (3), wherein the gasifier (1) comprises a shell (11), an ash outlet (16) is arranged at the bottom of the shell (11), a fluidizing distributor (4) is arranged above the ash outlet (16) of the shell (11), a plurality of gas inlets (15) are arranged between the fluidizing distributor (4) and the ash outlet (16) of the shell (11), a biomass inlet (14) is arranged above the fluidizing distributor (4) of the shell (11), the upper end of the shell (11) is connected to the cyclone separator (2), one end of the return pipe (3) is connected to the bottom of the cyclone separator (2), the other end of the return pipe (3) is connected to the shell and connected above the fluidizing distributor (4), and the gasifying agent of the fluidized bed gasifier is pure oxygen.

2. The fluidized bed gasifier according to claim 1, characterized in that: A lining (12) is arranged inside the shell (11); the shell (11) is made of high-strength heat-resistant alloy, and the lining (12) is made of heat-resistant insulation material.

3. The fluidized bed gasifier according to claim 1, characterized in that: The outer side of the shell (11), the outer side of the cyclone separator (2) and the outer side of the return pipe (3) are all covered with a jacket (13), and the gap between the jacket (13) and the shell (11), the gap between the cyclone separator (2) and the jacket (13) and the gap between the return pipe (3) and the jacket are all filled with water.

4. The fluidized bed gasifier according to claim 1, characterized in that: The fluidized distributor (4) comprises four layers of distributor plates (41), and the four layers of distributor plates (41) are spaced apart and distributed along the height direction of the shell (11); The distributor plate (41) located at the top is provided with a plurality of distribution valves (42), and the remaining distributor plates (41) are evenly provided with a plurality of air outlets and a plurality of distribution pipes (43) of different sizes.

5. The fluidized bed gasifier according to claim 4, characterized in that: The gas inlet (15) comprises a plurality of upper air inlets (151) arranged along the circumference of the shell (11) and a plurality of lower air inlets (152) arranged along the circumference of the shell (11), wherein the plurality of upper air inlets (151) are arranged between the first and second layers of the distributor plates (41) from bottom to top, and the lower air inlets (152) are located below the first layer of the distributor plates (41).

6. The fluidized bed gasifier according to claim 1, characterized in that: A leakage detection device (18) is provided on the top of the housing (11).

7. The fluidized bed gasifier according to any one of claims 1 to 6, characterized in that: The cyclone separator (2) has a synthesis gas inlet (21), a synthesis gas outlet (22) and a solid outlet (23), wherein the synthesis gas inlet (21) is arranged tangentially to the inner shell of the cyclone separator (2), and the solid outlet (23) is connected to the return pipe (3).

8. The fluidized bed gasifier according to claim 7, characterized in that: The cross section of the inlet end of the synthesis gas inlet (21) is circular.

9. The fluidized bed gasifier according to any one of claims 1 to 6, characterized in that: The return pipe (3) is provided with an anti-return device (5); The anti-return device (5) is an anti-return valve.

10. The fluidized bed gasifier according to claim 9, characterized in that: The anti-return valve comprises a lining shell (51), a pressure shell (52) wrapped outside the lining shell (51), a ventilation cover (53) arranged in the lining shell (51), and a wind cap (54) evenly distributed on the periphery of the ventilation cover (53).

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