Fixed bed biomass gasifier

Abstract

The utility model relates to the technical field of energy, in particular to a fixed bed biomass gasifier which comprises a feeding assembly, a gas inlet assembly, a slag discharging assembly, a fire grate and a gasifier body, the slag discharging assembly is arranged at the bottom of the gasifier body, the lower portion of the fire grate is arranged on the slag discharging assembly, and a through feeding through hole is formed in the center of the fire grate. A gasifying agent channel is arranged in the fire grate, and a gasifying agent through hole communicated with the gasifying agent channel is formed in the surface of the fire grate; the discharging end of the feeding assembly communicates with the lower portion of the feeding through hole, the gas outlet end of the gas inlet assembly communicates with the gasifying agent channel, the gas inlet assembly and the slag discharging assembly are arranged outside the furnace body, and a gas outlet is formed in the top of the furnace body. Through the bottom feeding structure, the overall height of the equipment is reduced; continuous feeding is achieved through the screw feeder, and gas outlet fluctuation caused by intermittent feeding is avoided. And the design of the crater fire grate and the annular fire grate is adopted, so that the gasifying agent can be uniformly distributed, and the preheating and drying effects of the fuel are good.

Description

Technical Field

[0001] The utility model relates to the technical field of energy, in particular to a fixed-bed biomass gasifier. Background Art

[0002] Biomass gasification is the process of converting biomass into combustible gases such as carbon monoxide (CO), hydrogen (H2), and methane (CH4) using air, oxygen, water vapor, or oxygen-containing gases as gasifying agents under certain temperature conditions through thermal conversion reactions such as oxidation, reduction, and pyrolysis. This process not only converts biomass waste into high-value fuel gas but also reduces the environmental pollution caused by direct biomass combustion.

[0003] Currently, fixed-bed gasifiers are a common biomass gasification device. Their basic principle is that biomass fuel is added from the top of the furnace, and the gasifying agent enters from the bottom. Through reverse contact with the biomass, a gasification reaction occurs to generate fuel gas. Although this design has certain application advantages, it still has some significant shortcomings:

[0004] The overall height of the traditional fixed-bed gasifier is relatively high, which makes transportation and installation inconvenient and places high requirements on the height and floor space of the equipment plant.

[0005] The intermittent addition of fuel from the top can easily cause fluctuations in the temperature and composition of the gas outlet, affecting the stability of the gas and increasing the dust in the gas.

[0006] Although the full water jacket design can prevent the furnace wall from overheating, it also increases energy consumption and reduces the overall thermal efficiency of the system. Utility Model Content

[0007] The technical problem to be solved by the present invention is that the existing fixed-bed biomass gasifier has problems such as excessively high equipment height, fluctuating gas outlet due to intermittent feeding, complex structure, and high energy consumption. The purpose is to provide a fixed-bed biomass gasifier that achieves the goals of reducing equipment height, continuous feeding, simplifying structure, and reducing energy consumption.

[0008] The utility model is achieved through the following technical solutions:

[0009] A fixed-bed biomass gasifier comprises: a feed assembly, an air intake assembly, a slag discharge assembly, a grate, and a furnace body, wherein the slag discharge assembly is arranged at the bottom of the furnace body, the grate is arranged above the slag discharge assembly, a feeding through-hole is provided at the center of the grate, a gasifying agent channel is provided inside the grate, and a gasifying agent through-hole connected to the gasifying agent channel is provided on the surface of the grate;

[0010] The discharge end of the feed assembly is connected to the lower part of the feeding through hole, the outlet end of the air intake assembly is connected to the gasifying agent channel, the air intake assembly and the slag discharge assembly are arranged outside the furnace body, and an air outlet is provided on the top of the furnace body.

[0011] Specifically, the grate is crater-shaped, the lower diameter of the grate is larger than the upper diameter of the grate, the feeding through-hole is coaxially arranged with the central axis of the grate, and the feeding through-hole connects the upper end face and the lower end face of the grate, the gasifier channel is an annular channel coaxial with the feeding through-hole, the gasifier through-hole is arranged along the radial direction of the grate, and the inner end of the gasifier through-hole is connected with the gasifier channel.

[0012] Optionally, the central axis of the gasifying agent through hole is arranged to be inclined upward.

[0013] Specifically, the feeding assembly includes: a fuel hopper, a horizontal screw feeder and a vertical screw feeder. The upper part of the vertical screw feeder is arranged in the feeding through hole, the lower end of the vertical screw feeder is connected to the discharge end of the horizontal screw feeder, and the feeding end of the horizontal screw feeder is connected to the discharge end of the fuel hopper.

[0014] Optionally, the slag discharge assembly includes: an annular grate and a slag collecting device, the annular grate is arranged at the bottom of the furnace body, the grate is arranged above the annular grate, a material air hole larger than the feeding through hole is provided in the middle of the annular grate, and the vertical screw feeder passes through the material air hole; a slag leakage hole adapted to the annular grate is provided on the ground of the furnace body, and the slag collecting device is arranged below the furnace body and adapted to the slag leakage hole.

[0015] Specifically, the slag collecting device includes: an annular collecting hopper, the upper portion of which is connected to the bottom of the furnace body, and a through hole adapted to the material gas hole is provided in the middle portion of the annular collecting hopper.

[0016] Specifically, the air intake assembly includes: a double-layer annular sleeve and a gasifying agent inlet. The double-layer annular sleeve passes through the material gas hole and is located outside the vertical screw feeder. The upper end of the double-layer annular sleeve is connected to the gasifying agent channel, and the lower end of the double-layer annular sleeve is provided with the gasifying agent inlet.

[0017] Furthermore, the gasification furnace also includes an equipment bracket, and an installation pit is set on the factory floor. The lower end of the furnace body is connected to the upper end of the equipment bracket, and the lower end of the equipment bracket is set in the installation pit. The feed assembly, the air intake assembly and the slag discharge assembly are all set in the installation pit.

[0018] Optionally, the furnace body includes an upper half structure and a lower half structure, the upper half structure is made of refractory material, the lower half structure is a water jacket structure, the grate is located in the lower half structure, and the air outlet is arranged at the top of the upper half structure.

[0019] Optionally, a water inlet joint is provided at the lower portion of the lower half structure, and a water outlet joint is provided at the upper portion of the lower half structure.

[0020] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0021] The fixed-bed biomass gasifier provided by the utility model includes: a feeding assembly, an air intake assembly, a slag discharge assembly, a grate and a furnace body. The slag discharge assembly is arranged at the bottom of the furnace body, and the lower part of the grate is installed on the slag discharge assembly. There is a penetrating feeding through-hole in the center of the grate, and an internal gasifying agent channel is provided to communicate with the surface gasifying agent through-hole. The feeding assembly feeds the fuel into the gasifier from the bottom through a screw feeder, and the air intake assembly feeds the gasifying agent into the gasifying agent channel of the grate, and finally the gasifying agent is evenly distributed into the furnace through the through-holes on the surface of the grate. An air outlet is provided on the top of the gasifier.

[0022] The fixed-bed biomass gasifier of the utility model significantly reduces the overall height of the equipment through the bottom feeding structure, facilitates transportation and installation, and reduces the cost of plant construction; the continuous bottom feeding method achieved by the screw feeder avoids the fluctuation of the gas outlet caused by intermittent feeding, improves the stability of the gas and reduces dust.

[0023] The "crater" grate and annular grate design ensures uniform distribution of the gasifying agent, improves fuel preheating and drying effects, and makes the gasification reaction more complete, thus enhancing the overall gasification effect. In addition, the two-stage structure of water jacket and refractory material effectively prevents damage to the furnace wall by high-temperature slag, reduces energy consumption, and increases the thermal efficiency of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings illustrate exemplary embodiments of the present invention and, together with the description thereof, are used to explain the principles of the present invention. These drawings are included to provide a further understanding of the present invention, and the accompanying drawings are included in and constitute a part of this specification and do not constitute a limitation on the embodiments of the present invention.

[0025] Figure 1 It is a structural schematic diagram of a fixed-bed biomass gasifier according to the utility model.

[0026] Figure markings: 1-fuel hopper, 2-horizontal screw feeder, 3-lower half structure, 4-grate, 5-annular grate, 6-air inlet assembly, 7-equipment bracket, 8-slag collecting device, 9-water inlet joint, 10-water outlet joint, 11-upper half structure, 12-air outlet. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the relevant content and are not intended to limit the present invention.

[0028] It should also be noted that, for the convenience of description, only the parts related to the present invention are shown in the drawings.

[0029] In this application, unless otherwise expressly specified or limited, terms such as "mounted," "connected," "connect," and "fixed" should be interpreted broadly. For example, they may refer to fixed connection, detachable connection, or integration; they may refer to direct connection or indirect connection through an intermediate medium; they may refer to internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0030] In this application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0031] In the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0032] Example 1

[0033] like Figure 1As shown, this embodiment provides a fixed-bed biomass gasifier, comprising: a feed assembly, an air intake assembly 6, a slag discharge assembly, a grate 4, and a furnace body, wherein the slag discharge assembly is arranged at the bottom of the furnace body, the lower portion of the grate 4 is arranged above the slag discharge assembly, a feeding through-hole is provided through the center of the grate 4, a gasifying agent channel is provided inside the grate 4, and a gasifying agent through-hole connected to the gasifying agent channel is provided on the surface of the grate 4;

[0034] The discharge end of the feed assembly is connected to the lower part of the feeding through hole, the outlet end of the air intake assembly 6 is connected to the gasifying agent channel, the air intake assembly 6 and the slag discharge assembly are arranged outside the furnace body, and an air outlet 12 is provided on the top of the furnace body.

[0035] The feeding assembly is responsible for delivering biomass fuel from the outside into the gasifier. Its discharge end is connected to the center of the grate 4 through a penetrating feeding through-hole. The feeding through-hole passes through the grate 4, so that the fuel can enter the core area of the gasifier from the discharge end of the feeding assembly, ensuring that the fuel can enter the furnace stably and continuously, thereby avoiding the intermittent problems caused by traditional top feeding.

[0036] The function of the air inlet assembly 6 is to deliver a gasifying agent (such as air, oxygen, or water vapor) into the gasifier. The gasifying agent is essential for gasifying biomass fuel. The outlet of the air inlet assembly 6 communicates with the gasifying agent channel within the grate 4. The gasifying agent channel is distributed throughout the grate 4 and evenly distributes the gasifying agent onto the fuel within the furnace through the gasifying agent holes on the grate 4 surface. This ensures that the gasifying agent fully contacts and participates in the fuel gasification reaction, improving gasification efficiency.

[0037] The slag discharge assembly, located at the bottom of the furnace, collects and removes the slag produced during the gasification process. Slag, the solid residue left over from the gasification process, is effectively removed from the furnace, keeping the interior clean and the reaction running smoothly.

[0038] The furnace body is the outer shell of the gasifier, containing all internal components and providing structural support. The slag removal assembly and gas inlet assembly 6 are both located outside the furnace body for easy maintenance and operation. A gas outlet 12 is located at the top of the furnace body to discharge combustible gases generated during the gasification process.

[0039] The fixed-bed biomass gasifier in this embodiment optimizes the feed and gasifying agent supply paths to ensure a thorough reaction between the fuel and gasifying agent within the furnace. Fuel is continuously fed from the bottom, and the gasifying agent is evenly distributed via the grate 4, allowing the fuel to undergo a gasification reaction at an appropriate temperature and gasifying agent concentration. The generated combustible gas is discharged from the top of the furnace, while the slag is removed through a slag removal assembly at the bottom. This design improves gasification efficiency, reduces equipment height and complexity, and facilitates installation and maintenance.

[0040] Example 2

[0041] like Figure 1 As shown, the grate 4 is crater-shaped, with a lower diameter greater than an upper diameter. The feed hole is coaxial with the center axis of the grate 4 and connects the upper and lower end surfaces of the grate 4. The gasifying agent channel is an annular channel coaxial with the feed hole. The gasifying agent channel is arranged along the radius of the grate 4, and the inner end of the gasifying agent channel is connected to the gasifying agent channel. The center axis of the gasifying agent channel is arranged obliquely upward.

[0042] The grate 4 is designed in a crater shape, with a larger diameter at the bottom than at the top. This allows the fuel to be more evenly distributed across the grate 4 upon entering it, gradually spreading outward from the center of the grate 4 to form a stable fuel accumulation layer. This structure helps optimize the contact surface between the fuel and the gasifying agent, improving gasification efficiency.

[0043] The feeding hole is set in the center of the grate 4 and is coaxial with the central axis of the grate 4. The feeding hole passes through the upper and lower end surfaces of the grate 4, so that the fuel can enter the grate 4 directly from the feed assembly through the feeding hole, ensuring that the fuel can enter the furnace stably and reducing possible blockages or other obstacles along the way.

[0044] The gasifying agent channel is an annular channel coaxial with the feed hole and located within the grate 4. It guides the gasifying agent from the air inlet assembly 6 to the surface of the grate 4 and evenly distributes it onto the fuel through the gasifying agent holes. This annular design allows the gasifying agent to flow evenly around the feed hole into the fuel accumulation layer, ensuring uniformity and efficiency of the gasification reaction.

[0045] Gasifying agent through-holes are arranged along the radius of grate 4, with their inner ends connected to the gasifying agent channels. Through these through-holes, the gasifying agent enters the surface of grate 4 from the annular channel and is evenly distributed on the fuel. To enhance contact between the gasifying agent and the fuel, the central axis of the gasifying agent through-holes is tilted upward, allowing the gasifying agent to more effectively penetrate the fuel layer.

[0046] Example 3

[0047] The following is a brief description of the feed assembly, slag discharge assembly and air intake assembly.

[0048] The feeding assembly includes: a fuel hopper 1, a horizontal screw feeder 2 and a vertical screw feeder. The upper part of the vertical screw feeder is arranged in the feeding through hole, the lower end of the vertical screw feeder is connected to the discharge end of the horizontal screw feeder 2, and the feeding end of the horizontal screw feeder 2 is connected to the discharge end of the fuel hopper 1.

[0049] A screw feeder is a mechanical device that conveys material via a rotating screw. Biomass fuel in the fuel hopper 1 first flows by gravity into the horizontal screw feeder 2, which then conveys the fuel horizontally to the lower end of the vertical screw feeder through its rotating screw. The vertical screw feeder then lifts the fuel vertically, passing it through a feed hole into the center of the gasifier. This ensures continuous and stable fuel delivery to the gasifier, effectively avoiding the intermittent issues associated with traditional top-feeding methods and improving gasification efficiency and gas stability.

[0050] The slag discharge assembly includes: an annular grate 5 and a slag collecting device 8. The annular grate 5 is arranged at the bottom of the furnace body, and the grate 4 is arranged above the annular grate 5. The annular grate is a rotating grate and the grate is a fixed grate. The two can rotate relative to each other during operation. A material air hole larger than the feeding through hole is provided in the middle of the annular grate 5, and a vertical screw feeder passes through the material air hole; a slag leakage hole adapted to the annular grate 5 is provided on the ground of the furnace body, and the slag collecting device 8 is arranged below the furnace body and adapted to the slag leakage hole.

[0051] The slag collecting device 8 comprises an annular collecting hopper, the upper portion of which is connected to the bottom of the furnace body, and a through hole adapted to the material gas hole is provided in the middle portion of the annular collecting hopper.

[0052] The annular grate 5 can adopt the existing technology. There are multiple material-discharging convex plates evenly arranged on the annular grate 5. Under the push of the annular grate 5, the slag slowly slides to the bottom edge of the gasification furnace body. The bottom of the furnace body has a concave-convex structure. The slag slides from the concave part to the next layer. Multiple scrapers are provided on the outer side of the bottom of the rotating grate. The scrapers scrape the sliding slag into the slag discharge device, and the slag is discharged and collected regularly according to the amount of slag produced.

[0053] The slag produced during the gasification process flows through the grate 4 and the annular grate 5 into the slag discharge hole at the bottom. The design of the annular grate 5 ensures uniform slag distribution and discharge. The slag then flows through the slag discharge hole into the annular collection hopper located below the furnace body. The annular design and the through-hole of the annular collection hopper ensure efficient slag collection without interfering with the normal operation of the vertical screw feeder. This design ensures a smooth and effective slag discharge process, preventing slag accumulation from impacting the normal operation of the gasifier.

[0054] The air intake assembly 6 includes: a double-layer annular sleeve and a gasifying agent inlet. The double-layer annular sleeve passes through the material air hole and is located outside the vertical screw feeder. The upper end of the double-layer annular sleeve is connected to the gasifying agent channel, and the lower end of the double-layer annular sleeve is provided with a gasifying agent inlet.

[0055] The double-layer annular sleeve has a double-layer structure. The gasifying agent enters the interlayer of the double-layer annular sleeve through the gasifying agent inlet, and by connecting the interlayer with the gasifying agent channel, the purpose of introducing the gasifying agent into the annular gasifying agent channel through one gasifying agent inlet is achieved.

[0056] The gasifier enters the lower end of the double-layer annular sleeve through the gasifier inlet from the outside. The gasifier flows in the double-layer annular sleeve and is evenly distributed into the gasifier channel through the annular structure. Then, the gasifier enters the gasifier through the gasifier channel and the gasifier through-hole, fully contacts and mixes with the fuel, and a gasification reaction occurs.

[0057] In summary, the feeding system in this embodiment is changed from top feeding to bottom feeding, the fuel is discharged from the hopper and transported to the bottom of the gasifier by a spiral, and then lifted to the middle of the fixed bed by a spiral feeding, and transported upward from the bottom center to the gasifier furnace by a spiral, so that the continuity of fuel feeding can be achieved; the biomass fuel is fed from the bottom, enters the gasifier furnace from the grate 4 of the "crater", and scatters to the surroundings. The fuel forms a certain accumulation height in the gasifier. Under certain temperature conditions, the fuel undergoes pyrolysis, reduction and oxidation reactions from top to bottom, and the completely reacted fuel slides to the annular rotating grate.

[0058] The gasifier is sucked in from the bottom inlet, and the furnace of the gasifier is slightly negatively pressurized. The gasifier enters the furnace from the gasifier through-hole on the grate 4, and undergoes an oxidation reaction with the fuel under high temperature conditions, releasing heat to maintain the reaction temperature. The generated gas contacts the fuel from bottom to top and continues to react. The organic matter in the fuel is gasified into biomass fuel gas and flows out from the top outlet.

[0059] Example 4

[0060] The gasifier also includes an equipment bracket 7. An installation pit is set on the factory floor. The lower end of the furnace body is connected to the upper end of the equipment bracket 7. The lower end of the equipment bracket 7 is set in the installation pit. The feed assembly, air intake assembly 6 and slag discharge assembly are all set in the installation pit.

[0061] The feeding device, air intake device and slag discharge device are all arranged at the bottom of the gasifier, and are installed on site below zero, reducing the top feeding mechanism and greatly reducing the layout height of the gasifier equipment; the height of the gasifier body is reduced, which can reduce the gasifier maintenance platform and stairs and other auxiliary facilities, simplify the equipment appearance, reduce the equipment manufacturing cost, facilitate the integrated design of the equipment, and the appearance of the gasifier is simple and beautiful; the fixed bed gasifier is designed with observation holes and inspection ports to facilitate production observation and equipment maintenance.

[0062] The furnace body includes an upper half structure 11 and a lower half structure 3. The upper half structure 11 is made of refractory material, and the lower half structure 3 is a water jacket structure. The grate 4 is located in the lower half structure 3, and the air outlet 12 is arranged at the top of the upper half structure 11. The lower part of the lower half structure 3 is provided with a water inlet joint 9, and the upper part of the lower half structure 3 is provided with a water outlet joint 10.

[0063] The upper half structure 11 is a low-temperature reaction zone. Its high-temperature resistance ensures the stability and safety of the reaction and efficiently maintains the gas temperature. The high-temperature gas generated during the gasification process is discharged from the gas outlet 12.

[0064] The water jacket system of the lower half of the structure 3 introduces cooling water through the water inlet connector 9. After circulating within the jacket and absorbing heat, the water is discharged through the water outlet connector 10, maintaining the cooling and stability of the lower half of the structure 3. The water jacket is located in the high-temperature section of the gasification reaction to prevent slag from adhering to the furnace body and affecting the uniform descent of the material layer during the gasification process. The upper refractory material is located in the low-temperature section of the gasification reaction, effectively maintaining the gas temperature.

[0065] In the description of this specification, the description with reference to the terms "one embodiment / method", "some embodiments / methods", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment / method or example are included in at least one embodiment / method or example of the present application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment / method or example. Moreover, the specific features, structures, materials or characteristics described may be combined in an appropriate manner in any one or more embodiments / methods or examples. In addition, those skilled in the art may combine and combine different embodiments / methods or examples described in this specification and the features of different embodiments / methods or examples, unless they are contradictory.

[0066] 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 the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. Throughout the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0067] Those skilled in the art will appreciate that the above embodiments are merely intended to clearly illustrate the present invention and are not intended to limit the scope of the present invention. Other variations or modifications may be made based on the above-described utility model, and such variations or modifications are still within the scope of the present invention.

Claims

1. A fixed bed biomass gasifier, characterized in that: include: A feed assembly, an air intake assembly (6), a slag discharge assembly, a grate (4) and a furnace body, wherein the slag discharge assembly is arranged at the bottom of the furnace body, the grate (4) is arranged above the slag discharge assembly, a feeding through hole is provided at the center of the grate (4), a gasifying agent channel is provided inside the grate (4), and a gasifying agent through hole communicating with the gasifying agent channel is provided on the surface of the grate (4); The discharge end of the feed assembly is connected to the lower part of the feed through hole, the outlet end of the air intake assembly (6) is connected to the gasifying agent channel, the air intake assembly (6) and the slag discharge assembly are arranged outside the furnace body, and the top of the furnace body is provided with an outlet (12).

2. The fixed bed biomass gasifier according to claim 1, characterized in that: The grate (4) is crater-shaped, the lower diameter of the grate (4) is larger than the upper diameter of the grate (4), the feeding through hole is coaxially arranged with the central axis of the grate (4), and the feeding through hole is connected to the upper end face and the lower end face of the grate (4), the gasifying agent channel is an annular channel coaxial with the feeding through hole, the gasifying agent through hole is arranged along the radial direction of the grate (4), and the inner end of the gasifying agent through hole is connected to the gasifying agent channel.

3. The fixed bed biomass gasifier according to claim 2, characterized in that: The central axis of the gasifying agent through hole is arranged to be inclined upward.

4. The fixed bed biomass gasifier according to claim 1, characterized in that: The feeding assembly comprises: a fuel hopper (1), a horizontal screw feeder (2) and a vertical screw feeder, wherein the upper portion of the vertical screw feeder is arranged in the feeding through hole, the lower end of the vertical screw feeder is connected to the discharge end of the horizontal screw feeder (2), and the feeding end of the horizontal screw feeder (2) is connected to the discharge end of the fuel hopper (1).

5. The fixed bed biomass gasifier according to claim 4, characterized in that: The slag discharge assembly comprises: an annular grate (5) and a slag collecting device (8); the annular grate (5) is arranged at the bottom of the furnace body; the grate (4) is arranged above the annular grate (5); a material air hole larger than a feeding through hole is provided in the middle of the annular grate (5); the vertical screw feeder passes through the material air hole; a slag leakage hole adapted to the annular grate (5) is provided on the floor of the furnace body; the slag collecting device (8) is arranged below the furnace body and adapted to the slag leakage hole.

6. The fixed bed biomass gasifier according to claim 5, characterized in that: The slag collecting device (8) comprises: an annular collecting hopper, the upper portion of which is connected to the bottom of the furnace body, and a through hole adapted to the material gas hole is provided in the middle portion of the annular collecting hopper.

7. The fixed-bed biomass gasifier according to claim 5, characterized in that: The air intake assembly (6) comprises: a double-layer annular sleeve and a gasifying agent inlet, the double-layer annular sleeve passes through the material gas hole and is located outside the vertical screw feeder, the upper end of the double-layer annular sleeve is connected to the gasifying agent channel, and the lower end of the double-layer annular sleeve is provided with the gasifying agent inlet.

8. The fixed-bed biomass gasifier according to claim 1, characterized in that: It also includes an equipment bracket (7), and an installation pit is set on the factory floor. The lower end of the furnace body is connected to the upper end of the equipment bracket (7), and the lower end of the equipment bracket (7) is set in the installation pit. The feeding component, the air intake component (6) and the slag discharge component are all set in the installation pit.

9. The fixed-bed biomass gasifier according to claim 1, characterized in that: The furnace body comprises an upper half structure (11) and a lower half structure (3), wherein the upper half structure (11) is made of refractory material, the lower half structure (3) is a water jacket structure, the grate (4) is located in the lower half structure (3), and the air outlet (12) is arranged at the top of the upper half structure (11).

10. The fixed-bed biomass gasifier according to claim 9, characterized in that: The lower part of the lower half structure (3) is provided with a water inlet joint (9), and the upper part of the lower half structure (3) is provided with a water outlet joint (10).

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