A fluidized bed gasifier

Abstract

This invention discloses a fluidized bed gasifier, comprising a gasifier, a cyclone separator, and a return pipe. The gasifier includes a shell with an ash outlet at its bottom. A fluidized bed distributor is positioned above the ash outlet. Multiple gas inlets are located between the fluidized bed distributor and the ash outlet. A biomass inlet is positioned above the fluidized bed distributor and 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, and the other end is connected to the shell and above the fluidized bed distributor. The gasifying agent in the fluidized bed gasifier is pure oxygen. This invention uses pure oxygen as the gasifying agent, and the gas inlet is located below the fluidized bed distributor. The pure oxygen entering the gasifier is evenly distributed by the fluidized bed distributor and then contacts the biomass, ensuring complete biomass gasification and preventing the formation of molten ash slag that blocks the gasifier outlet.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of biomass gasification, in particular to a fluidized bed gasifier. BACKGROUND

[0002] The fluidized bed gasifier mainly uses the conical air distributor at the bottom of the furnace body to blow the biomass particles in the furnace body to make them suspended in the airflow, and makes the biomass particles produce combustible gas through the oxidation reaction of the oxygen-rich air gasification agent and the biomass particles, the oxidation reaction mainly occurs at the bottom of the furnace body, the airflow goes up and drives the biomass particles to circulate upward, producing combustible gas and semi-coke, the semi-coke is returned to the furnace body through the return device for secondary reaction, and the combustible gas is used after dust removal.

[0003] At present, the fluidized bed gasifier uses air as the gasification agent, and the pressure is also normal pressure, which leads to low temperature, low gasification efficiency, insufficient biomass pyrolysis gasification, high tar content in the synthesis gas and other shortcomings, and the fluidized bed gasifier sprays the gasification agent and the fluidizing agent into the furnace body through the burner, the gas sprayed into the furnace body through the burner is unevenly distributed, which easily leads to incomplete biomass gasification or local area temperature too high, forming molten ash slagging and blocking the gasification furnace outlet.

[0004] At the same time, the fluidized bed gasifier of the prior art is in the form of lining the shell with refractory bricks, the ash in the furnace will erode the refractory bricks, and the gas-solid medium in the gasification of coal will penetrate into the gaps of the refractory bricks, causing the refractory bricks to crack, damage and even large pieces to fall off, and the local over-temperature of the gasification furnace shell causes great safety hazards. SUMMARY

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

[0006] In order to achieve the above-mentioned application purposes, the technical scheme adopted by the present application is: a fluidized bed gasifier, comprising a gasifier, a cyclone separator and a return pipe, the gasifier comprises a shell, the bottom of the shell is provided with an ash outlet, the shell is provided with a fluidization distributor above the ash outlet, the shell is provided with a plurality of gas inlets between the fluidization distributor and the ash outlet, the shell is provided with a biomass inlet above the fluidization distributor, the biomass inlet is connected with a feeding device, the upper end of the shell is connected with the cyclone separator, one end of the return pipe is connected with the bottom of the cyclone separator, the other end of the return pipe is connected with the shell and is connected above the fluidization distributor, and the gasification agent of the fluidized bed gasifier is pure oxygen.

[0007] Further, the shell is internally provided with a lining, 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 gaps between the shell and the jacket, the cyclone separator and the jacket and the return pipe and the jacket are all filled with water.

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

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

[0011] Further, the gas inlet comprises a plurality of upper gas inlets arranged circumferentially along the shell and a plurality of lower gas inlets arranged circumferentially along the shell, the plurality of upper gas inlets are arranged between the first layer and the second layer of the distributor plates from bottom to top, and the lower gas inlets are arranged below the first layer of the distributor plates.

[0012] Further, the top of the shell is provided with a leakage detection device.

[0013] Further, 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 with the return pipe.

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

[0015] Further, the return pipe is provided with a backflow prevention device.

[0016] The backflow prevention device is a backflow prevention valve.

[0017] Further, the backflow prevention valve comprises a liner shell, a pressure shell wrapped outside the liner shell, a breather cover arranged in the liner shell and a bonnet uniformly arranged around the breather cover.

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

[0019] The present application uses pure oxygen as the gasification agent, and the gas inlet is arranged below the fluidization distributor, so that the pure oxygen entering the gasification furnace is uniformly distributed by the fluidization distributor and then contacts the biomass, so that the biomass is completely gasified, avoiding the formation of molten ash and slag to block the outlet of the gasification furnace, and the lining made of heat-resistant and heat-insulating material arranged in the gasification furnace avoids the local over-temperature of the shell of the gasification furnace, which causes a huge safety hazard.

[0020] Meanwhile, the jacket is wrapped outside the shell of the gasification furnace, outside the cyclone separator and outside the back feeding pipe, so that the temperature distribution in the fluidized bed gasification furnace is more uniform, and the damage caused by temperature difference stress is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the fluidized bed gasification furnace of the present application.

[0022] Figure 2 It is a sectional view of the fluidized bed gasification furnace of the present application.

[0023] Figure 3 It is Figure 2 the sectional view in A-A direction.

[0024] Figure 4 It is Figure 2 the sectional view in B-B direction.

[0025] Figure 5 It is Figure 2 the sectional view in C-C direction.

[0026] Figure 6 It is the sectional view of the back feeding prevention valve of the present application. DETAILED DESCRIPTION

[0027] In order to make the personnel in the technical field better understand the present application scheme, the technical scheme in the present application embodiment will be described clearly and completely in combination with the drawings in the present application embodiment. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by the person skilled in the art without creative labor should belong to the scope of protection of the present application.

[0028] It should be noted that the terms "first", "second" and the like in the specification and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily have to describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units 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", "transverse", "longitudinal" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not intended 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, in addition to indicating the orientation or positional relationship, the above-mentioned partial terms may also be used to indicate other meanings, for example, the term "upper" may also be used to indicate a certain dependent relationship or connection relationship in some cases. For those skilled in the art, the specific meaning of these terms in the present application can be understood according to the specific circumstances.

[0031] In addition, the terms "mounting", "setting", "provided with", "connecting", "connecting", "sleeving" should be broadly understood. For example, it can be fixedly connected, detachably connected, or integrally constructed; it can be mechanically connected or electrically connected; it can be directly connected, or indirectly connected through an intermediate medium, or internal communication between two devices, elements or components. For those skilled in the art, the specific meaning of the above-mentioned terms in the present application can be understood according to the specific circumstances.

[0032] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0033] Reference Figures 1 to 6 The present application provides a fluidized bed gasifier, which comprises a gasifier 1, a cyclone separator 2 and a return pipe 3. The gasifier 1 comprises a shell 11, the bottom of the shell 11 is provided with an ash outlet 16, the shell 11 is provided with a fluidization distributor 4 above the ash outlet 16, the shell 11 is provided with a plurality of gas inlets 15 between the fluidization distributor 4 and the ash outlet 16, the shell 11 is provided with a biomass inlet 14 above the fluidization distributor 4, the biomass inlet 14 is connected with a feeding device, the upper end of the shell 11 is connected with the cyclone separator 2, one end of the return pipe 3 is connected with the bottom of the cyclone separator 2, and the other end of the return pipe 3 is connected with the shell and above the fluidization distributor 4.

[0034] The fluidized bed gasifier of the present application uses pure oxygen as the gasification agent and carbon dioxide as the fluidization agent.

[0035] The present application sets the gas inlet 15 below the fluidization distributor 4, so that the gasification agent and fluidization agent entering the gasification furnace 1 through the gas inlet 15 need to pass through the fluidization distributor 4 to contact the biomass located above the fluidization distributor 4, the fluidization distributor 4 can uniformly distribute the gas to the above of the fluidization distributor 4, so that the gas flow is more uniform, so that the biomass gasification is complete, and the molten ash slagging is avoided to block the vaporization furnace outlet.

[0036] Further, the shell 11 is internally provided with a lining 12, the shell 11 is made of high-strength heat-resistant alloy, and the lining 12 is made of heat-resistant and heat-insulating material. The lining 12 made of heat-resistant and heat-insulating material can avoid the erosion of the refractory bricks by the ash in the furnace, and avoid the local over-temperature of the gasification furnace shell causing great safety hazards.

[0037] Further, 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 wrapped with a jacket 13, 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 gasification furnace more uniform and always within the safe temperature range, reducing the damage caused by temperature difference stress.

[0038] Further, the fluidization distributor 4 includes four layers of distributor plates 41, which are spaced apart along the height direction of the shell 11.

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

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

[0041] Preferably, the lower gas inlets 152 are inclined downward, so that the gas inlet direction is inclined upward, so that the gas flow flows toward the fluidization distributor 4.

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

[0043] Further, 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 with the return pipe 3.

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

[0045] Preferably, the internal lining of the syngas inlet 21 is a rectangular gradient structure, i.e. the size of the inlet end of the syngas inlet 21 is larger than that of the outlet end. In order to compress the overall size as much as possible, the inlet end of the syngas inlet 21 also adopts a tangent structure.

[0046] Further, the return pipe 3 is provided with a backflow prevention device 5 to prevent solids from being returned to the cyclone separator 2 from the gasifier 1.

[0047] Further, the backflow prevention device 5 is a backflow prevention valve.

[0048] Further, the backflow prevention valve comprises a lining shell 51, a pressure shell 52 wrapped outside the lining shell 51, an air cover 53 arranged in the lining shell 51, and a wind cap 54 uniformly distributed around the air cover 53, and the air cover 53 is made of high-temperature-resistant high-alloy material. The present application utilizes the natural pressure difference formed by the weight of the material itself, and the wind cap uniformly distributed around the periphery ensures the stable circulation of the material. The outer pressure shell is designed as a two-section tapered shell with a folded edge structure to avoid large stress concentration and can withstand high pressure. At the same time, in order to ensure the smoothness and stability of the material circulation, the air cover is uniformly distributed with specially designed wind caps 54 around the periphery. These wind caps 54 not only optimize the air flow distribution and effectively prevent the material from blocking or accumulating during the circulation process, but also further enhance the overall efficiency and stability of the air structure.

[0049] Preferably, the lining shell 51 and the pressure shell 52 both adopt a two-section tapered shell structure with a folded edge. 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 tapered shell, significantly improving the load-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, so that it can maintain the integrity and functionality of the structure under extreme working conditions.

[0050] The foregoing description of the disclosed embodiments enables a person skilled in the art to make or use the application. Modifications of the above-described embodiments can become apparent to those skilled in the art, and the foregoing description is intended to cover such modifications as fall within the scope of the application. Accordingly, the application should not be limited to the above-described embodiments, but should be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A fluidized bed gasifier, characterized by, The fluidized bed gasification furnace comprises a gasification furnace (1), a cyclone separator (2) and a back feeding pipe (3), the gasification furnace (1) comprises a shell (11), the bottom of the shell (11) is provided with an ash outlet (16), the shell (11) is provided with a fluidization distributor (4) above the ash outlet (16), the shell (11) is provided with a plurality of gas inlets (15) between the fluidization distributor (4) and the ash outlet (16), the shell (11) is provided with a biomass inlet (14) above the fluidization distributor (4), the upper end of the shell (11) is connected with the cyclone separator (2), one end of the back feeding pipe (3) is connected with the bottom of the cyclone separator (2), the other end of the back feeding pipe (3) is connected with the shell and is arranged above the fluidization distributor (4), and the gasification agent of the fluidized bed gasification furnace is pure oxygen. The fluidization distributor (4) comprises four layers of distributor plates (41), the four layers of distributor plates (41) are arranged at intervals along the height direction of the shell (11), the distributor plate (41) at the top is provided with a plurality of distribution valves (42), and the remaining distributor plates (41) are uniformly provided with a plurality of air outlets and a plurality of distribution pipes (43) with different sizes. The gas inlets (15) comprise a plurality of upper gas inlets (151) arranged in the circumferential direction of the shell (11) and a plurality of lower gas inlets (152) arranged in the circumferential direction of the shell (11), the plurality of upper gas inlets (151) are arranged between the first layer and the second layer of the distributor plates (41) from bottom to top, and the lower gas inlets (152) are arranged below the first layer of the distributor plates (41). The cyclone separator (2) has a synthetic gas inlet (21), a synthetic gas outlet (22) and a solid outlet (23), the inlet end of the synthetic gas inlet (21) is circular in cross section, the inside lining of the synthetic gas inlet (21) is in a rectangular gradient structure, the synthetic gas inlet (21) is arranged in a tangent line with the inner shell of the cyclone separator (2), and the solid outlet (23) is connected with the back feeding pipe (3).

2. The fluidized bed gasifier of claim 1, wherein, The shell (11) is internally provided with a lining (12), the shell (11) is made of high-strength heat-resistant alloy, and the lining (12) is made of heat-resistant and heat-insulating material.

3. The fluidized bed gasifier of claim 1, wherein, The outer side of the shell (11), the outer side of the cyclone separator (2) and the outer side of the back feeding pipe (3) are all wrapped with a jacket (13), and the gaps between the shell (11) and the jacket (13), the cyclone separator (2) and the jacket (13) and the back feeding pipe (3) and the jacket are all filled with water.

4. The fluidized bed gasifier of claim 1 wherein, The top of the shell (11) is provided with a leakage detection device (18).

5. The fluidized bed gasifier according to any one of claims 1 to 4, wherein The back feeding pipe (3) is provided with a back feeding prevention device (5). The back feeding prevention device (5) is a back feeding prevention valve.

6. The fluidized bed gasifier of claim 5, wherein, The anti-return valve comprises a lining shell (51), a pressure shell (52) wrapped outside the lining shell (51), a breather cover (53) arranged in the lining shell (51) and a wind cap (54) uniformly distributed on the periphery of the breather cover (53).

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