Grate device of biomass gasifier

Abstract

The utility model discloses a biomass gasification furnace grate device, which comprises a fire grate, an ash basin, a base, a bracket, a three-way air guide pipe, a fan and a driving mechanism, the fire grate is rotatably arranged in a gasification furnace and is positioned at the bottom of the gasification furnace, a blanking gap is arranged between the fire grate and the furnace wall of the gasification furnace, a plurality of first ash knives are arranged on the inner wall of the furnace wall of the gasification furnace, and a plurality of second ash knives are arranged on the base. The plurality of first ash knives are annularly arranged along the axis of the gasification furnace in sequence; the base is arranged at the bottom of the fire grate and rotationally arranged on the support, and the driving mechanism is in transmission connection with the base and used for driving the base and the fire grate to rotate. The device has the technical effects that the air inlet amount can be accurately controlled, and corresponding gasification air amounts can be conveniently provided for different gasification raw materials, so that the yield and the quality of fuel gas and activated carbon can meet the requirements; the fire grate is in a tower shape and is matched with a second ash knife on the ash basin and a first ash knife on the inner wall of the gasification furnace, so that sufficient combustion of biomass fuel is guaranteed, and generated charcoal ash can be automatically and timely discharged.

Description

Technical Field

[0001] This utility model relates to the field of biomass gasification technology, specifically to a biomass gasification furnace grate device. Background Technology

[0002] Biomass refers to all living, growing organic matter produced through photosynthesis from the atmosphere, water, and land. It includes plants, animals, and microorganisms. Biomass waste refers to biomass that has lost its original value or has not been utilized within a certain time and space, resulting in its abandonment. Biomass waste treatment faces the following problems: large volume, low utilization rate, great development potential, and urgent environmental governance.

[0003] Biomass pyrolysis gasification refers to the process of crushing and drying biomass raw materials, then feeding them into a gasifier for gasification and pyrolysis under anaerobic conditions to obtain combustible gases. The principle of biomass gasification is that, under certain thermodynamic conditions, with the help of a gasification medium (air, oxygen, or water vapor, etc.), the polymers of biomass undergo pyrolysis, oxidation, and reduction reactions. The organic matter generated during pyrolysis is further thermally or catalytically cracked into smaller hydrocarbon molecules, yielding gases such as CO, H2, and CH4. The most fundamental difference between biomass pyrolysis gasification and direct incineration technology is that pyrolysis gasification technology largely solves the problem of flue gas pollution, eliminating secondary pollution and ensuring that flue gas emissions meet standards.

[0004] In biomass gasification, the gasification equivalence ratio (ER) needs to be strictly controlled. The ER reflects the oxygen consumption during gasification; a higher ER indicates greater oxygen consumption, leading to a higher reaction temperature, which is beneficial for the gasification reaction. However, it also means an increased proportion of biomass burned, resulting in more carbon dioxide production and a lower calorific value. Therefore, determining the ER requires considering various factors. Empirically, the ER value generally ranges from 0.2 to 0.4. The ER is a crucial influencing factor in biomass gasification, affecting not only the quality of the gasified gas but also the thermal efficiency of the gasification process.

[0005] A rotary grate is a component in a biomass gasifier that holds solid fuel and enables its effective combustion. However, existing rotary grates in biomass gasifiers lack a defined gasification reaction zone, cannot supply gasification air according to reaction requirements, resulting in incomplete gasification and insufficient fuel production. Furthermore, the biomass feedstock is not stirred or tumbled within the gasifier, leading to incomplete reaction. Rotary grates are generally horizontal, making ash removal difficult. While some designs are conical to facilitate ash removal, the biomass feedstock may still fall into the ash collection port without participating in the reaction. Therefore, a new rotary grate for biomass gasifiers is urgently needed to address these issues. Utility Model Content

[0006] Therefore, this utility model provides a biomass gasification furnace grate device to solve the above-mentioned problems in the prior art.

[0007] To achieve the above objectives, this utility model provides the following technical solution:

[0008] According to a first aspect of this utility model, a biomass gasification furnace grate device includes a grate, an ash basin, a base, a support, a three-way air duct, a blower, and a drive mechanism. The grate is rotatably disposed inside the gasification furnace and is located at the bottom of the gasification furnace. A material discharge gap is provided between the grate and the furnace wall of the gasification furnace. A plurality of first ash knives are provided on the inner wall of the gasification furnace wall, and the plurality of first ash knives are arranged in a ring along the axis of the gasification furnace.

[0009] The ash basin is located at the bottom of the gasifier, and the ash basin is filled with sealing water.

[0010] The base is disposed at the bottom of the grate, the base is rotatably mounted on the support, the drive mechanism is connected to the base for transmission, and the drive mechanism is used to drive the base and the grate to rotate;

[0011] The grate is tower-shaped, and the three-way air duct is located at the bottom of the support. The first port of the three-way air duct is connected to the grate, the second port of the three-way air duct is connected to the air outlet of the blower, and the third end of the three-way air duct is inserted into the pit, which is filled with sealing water.

[0012] Furthermore, the grate includes a grate tower, a cover, a gas chamber, and a ventilation pipe. The grate tower is conical, the cover is located at the top of the grate tower, the gas chamber is inverted conical, the top of the gas chamber is connected to the bottom of the grate tower, the top of the ventilation pipe is connected to the bottom of the gas chamber, and the bottom of the ventilation pipe is connected to the first end of the three-way air guide pipe.

[0013] The grate tower has multiple air supply layers on its side wall. The air supply layers are annular and are arranged sequentially along the height of the grate tower. Each air supply layer has multiple gasification air holes, and each gasification air hole is equipped with a nozzle.

[0014] Furthermore, the nozzle has a circular inlet and a flat outlet.

[0015] Furthermore, the number of air supply layers is 4 to 9.

[0016] Furthermore, the inclination angle of the grate tower sidewall is 45° to 65°.

[0017] Furthermore, an annular sleeve is fitted around the outside of the ventilation pipe. The inner diameter of the annular sleeve is smaller than the diameter of the ventilation pipe, and the outer diameter of the annular sleeve is larger than the diameter of the ventilation pipe. The inner and outer rings of the annular sleeve are hollow. The bottom end of the ventilation pipe is inserted between the inner and outer rings of the annular sleeve. The bottom end of the annular sleeve is sealed. The first end of the three-way air guide pipe passes through the bottom of the annular sleeve and is inserted into the ventilation pipe. Sealing water is provided inside the annular sleeve.

[0018] Furthermore, the base is cylindrical, and a plurality of second trowels are provided on the outer side wall of the base. The plurality of second trowels are arranged in a ring along the axis of the base, and adjacent second trowels are staggered vertically. The plurality of second trowels are all located inside the trowel basin.

[0019] Furthermore, the number of the second gray blades is 2 to 8.

[0020] Furthermore, the ash basin is inverted conical in shape, and multiple round steel bars are provided on the inner wall of the ash basin, with the multiple round steel bars arranged in a ring along the axis of the ash basin.

[0021] Furthermore, the drive mechanism includes a drive motor, a large gear, and a small gear. The large gear is disposed at the bottom of the base, coaxial with the base, and mounted on a rolling bearing, which is mounted on the bracket.

[0022] The pinion meshes with the large gear, and the output end of the drive motor is connected to the pinion via a transmission.

[0023] This utility model has the following advantages: by setting up an air supply layer and nozzles, the air intake can be precisely controlled; by setting a reasonable gasification equivalence ratio range for the gas-carbon co-production of the fixed bed gasifier, it is convenient to provide the corresponding gasification air volume for different gasification raw materials, so that the output and quality of gas and activated carbon can meet the requirements; the grate has a tower-shaped structure, which, together with the second ash knife on the ash basin and the first ash knife on the inner wall of the gasifier, ensures the full combustion of biomass fuel and allows the generated ash to be automatically and timely discharged. Attached Figure Description

[0024] To more clearly illustrate the embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0025] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the implementation conditions of this utility model. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationships, or adjustments to the size, without affecting the effects and purposes that this utility model can produce, should still fall within the scope of the technical content disclosed in this utility model.

[0026] Figure 1 A front view of a biomass gasification furnace grate device provided for some embodiments of this utility model.

[0027] Figure 2 A cross-sectional view of a biomass gasification furnace grate device provided for some embodiments of this utility model.

[0028] Figure 3 This is a top view of a biomass gasification furnace grate device provided for some embodiments of the present invention.

[0029] Figure 4 This is a schematic diagram of the grate structure of a biomass gasification furnace grate device provided for some embodiments of this utility model.

[0030] Figure 5 This is a schematic diagram of the structure of the second ash knife of a biomass gasification furnace grate device provided in some embodiments of the present invention.

[0031] In the diagram: 1. Gasifier wall, 101. First ash cutter, 2. Grate, 201. Grate tower, 202. Cover, 203. Air supply layer, 204. Gas chamber, 205. Ventilation pipe, 206. Gasification air hole, 207. Nozzle, 3. Ash basin, 301. Round steel, 4. Base, 401. Second ash cutter, 5. Large gear, 6. Small gear, 7. Drive motor, 8. Rolling bearing, 9. Support, 10. Annular sleeve, 11. T-junction air duct, 12. Fan. Detailed Implementation

[0032] The following specific embodiments illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0033] like Figures 1 to 5As shown in the first aspect embodiment of this utility model, a biomass gasification furnace grate device includes a grate 2, which is disposed inside the gasification furnace and located at its bottom. A material discharge gap is provided between the gasification furnace wall 1 and the grate 2. An ash basin 3 is provided on the lower side of the gasification furnace wall 1, and the ash basin 3 is filled with sealing water. The sealing water is used to seal the material discharge gap at the bottom of the gasification furnace wall 1 to prevent air leakage, and at the same time to cool and clean the collected ash, reducing dust pollution. A plurality of first ash knives 101 are provided on the inner wall of the gasification furnace wall 1. The plurality of first ash knives 101 are arranged in a ring along the axis of the gasification furnace. A base 4 is provided on the lower side of the grate 2, and the grate 2 is welded to the base 4. A large gear 5 is provided at the lower part of the ash basin 3 and the base 4 and is welded to it. The large gear 5 is meshed with a small gear 6, and the small gear 6 is driven by the output shaft of the drive motor 7. The large gear 5 is equipped with a corresponding rolling bearing 8. The lower part of the rolling bearing 8 is provided with a bracket 9 to support the entire rotating grate. The bracket 9 is welded to the rolling bearing 8. The bracket 9 is rotatably connected to the grate 2, the base 4, and the ash basin 3 through the rolling bearing 8. Below the grate 2 is an annular sleeve 10. The lower part of the annular sleeve 10 is provided with a three-way air guide pipe 11. One end of the three-way air guide pipe 11 is inserted into the pit, which is filled with a certain amount of sealing water. The other end is connected to the blower 12.

[0034] The grate 2 has a tower-like structure and includes a grate tower 201, a cover 202 set on the top of the grate tower 201, an air supply layer 203, an air chamber 204, and a ventilation pipe 205. The air supply layer 203 includes vaporized air holes 206 and nozzles 207. The air supply layer 203 has multiple layers, which are arranged sequentially along the height direction of the grate tower 201 on its side wall. Each air supply layer 203 has multiple vaporized air holes 206, which increase with each layer. The vaporized air holes 206 of adjacent air supply layers 203 are arranged alternately, and each vaporized air hole 206 is equipped with a nozzle 207. The grate tower 201 is located at the top of the gas chamber 204. The gas chamber 204 is welded to and communicates with the grate tower 201. The ventilation pipe 205 is welded to and communicates with the gas chamber 204. Air passes sequentially through the ventilation pipe 205 and the gas chamber 204 to reach the grate tower 201. Then, it is supplied uniformly to the gasifier body through the nozzle 207, ensuring the gasification equivalence ratio of the gasifier and thus ensuring complete combustion of biomass. This increases char production while maintaining the calorific value of the gasified gas. The nozzle 207 has a circular inlet and a flat outlet, facilitating increased outlet flow rate and preventing clogging.

[0035] The air supply layer 203 has 4 to 9 layers, and the size of the air supply layer 203 gradually increases from top to bottom. The multi-layer air supply layer 203 is divided into an uppermost air supply layer, an intermediate air supply layer, and a lowermost air supply layer. The angle between the line connecting the sides of the uppermost and lowermost air supply layers and the horizontal plane is the grate inclination angle, which is set to 45° to 65° to facilitate the separation of the char ash formed after gasification.

[0036] The base 4 has a cylindrical structure, and a second ash shaving 401 is provided on the outer wall. The second ash shaving 401 is a fixed structural component that is smaller at the top and larger at the bottom, and it is curved towards the rotating side of the grate. The height of the second ash shaving 401 is 50mm to 200mm. Two to eight second ash shavings are provided, evenly distributed on the outer side of the base 4, with adjacent second ash shavings staggered vertically by a distance of 50mm to 80mm. The second ash shavings 401 can constantly stir the ash in the ash basin, ensuring complete combustion of biomass, and can also achieve automatic ash removal, reducing manual ash removal.

[0037] The ash basin 3 has an inverted conical structure with a large upper opening and a small lower opening. Multiple round steel bars 301 are provided on the side wall of the ash basin 3. Each round steel bar 301 is arranged along the height direction of the ash basin 3. The multiple round steel bars 301 are arranged in a ring along the axis of the ash basin 3. The round steel bars 301 are welded to the ash basin 3 and are evenly distributed to play the role of material feeding.

[0038] The large gear 5 meshes with the small gear 6, and the output shaft of the drive motor 7 is connected to the small gear 6. The drive motor 7 is used to drive the grate 2 to rotate. The start and stop frequency of the drive motor 7 can be set by the program to ensure the slag discharge frequency of the rotating grate and avoid untimely and incomplete slag discharge, which would affect the biomass fuel gasification.

[0039] The large gear 5 and the rolling bearing 8 are hollow in the middle so that the ventilation pipe 205 can be inserted into the annular sleeve 10. The annular sleeve 10 contains sealing water, which not only plays a sealing role, but also acts as a water seal explosion relief device to ensure the safe operation of the entire grate. During the rotation of the grate, the ventilation pipe 205 can rotate inside the annular sleeve 10, while the annular sleeve 10, the three-way air guide pipe 11 connected to it, and the fan 12 remain stationary.

[0040] The upper part of the rolling bearing 8 is welded to the large gear 5, and the lower part is welded to the bracket 9. The bracket 9 is fixed. The rolling bearing 8 causes the grate 2 and the ash basin 3 to rotate. The ash in the ash basin 3 is discharged to the outside of the ash basin 3 by the scraping action of the first ash knife 101, and then the ash is collected by the receiving device.

[0041] The outer diameter of the annular sleeve 10 is 30mm to 60mm larger than the diameter of the ventilation pipe 205, while the inner diameter of the annular sleeve 10 is 30mm to 60mm smaller than the diameter of the ventilation pipe. The upper part between the outer and inner rings of the annular sleeve 10 is hollow to allow the ventilation pipe 205 to be inserted. The bottom between the outer and inner rings of the annular sleeve 10 is sealed with a sealing plate to hold sealing water. The distance between the bottom sealing plate of the annular sleeve 10 and the inserted ventilation pipe 205 is 50mm to 150mm.

[0042] The annular sleeve 10 is flange-connected to the three-way air duct 11. One end of the three-way air duct 11 is inserted into the pit to a depth of 300mm to 700mm, and the other end is connected to the blower 12. When the blower 12 blows air into the furnace, the air enters the gasifier sequentially through the three-way air duct 11, the annular sleeve 10, the ventilation pipe 205, the air chamber 204, and the nozzle 207.

[0043] In this embodiment, a 1t / h biomass fixed-bed gasifier produces enough biogas to supply a 3t / h steam boiler. The gasification feedstock is straw pellets, with a straw pellet consumption of 1 ton / hour and a gasification air volume of 1040 m³. 3 / h, equivalent to a gasification equivalent ratio of 0.28, grate inclination angle of 52°, uniform air supply layer 203 has seven layers, base 4 has four second ash knives 401, the spacing between adjacent second ash knives 401 is 70mm; ash basin 3 has 20 round steel bars 301, which can make the generated carbon blocks and carbon rods discharged from the furnace in time; the outer diameter of the annular sleeve 10 is 50mm larger than the diameter of the ventilation pipe 205, and the inner diameter of the annular sleeve 10 is 50mm smaller than the diameter of the ventilation pipe; the distance between the bottom sealing plate of the annular sleeve 10 and the inserted ventilation pipe 205 is 100mm; one of the three-way air guide pipes 11 is inserted into the pit to a depth of 500mm, and the other is connected to the blower 12.

[0044] Biomass feedstock enters the gasifier via a feeding device and passes through the drying zone, pyrolysis zone, reduction zone, oxidation zone, and slag zone in sequence. While the biomass feedstock is in motion, it completes the entire process of fuel drying, pyrolysis, reduction, and oxidation.

[0045] The ash basin 3 is pre-filled with water for water sealing. This water seal can ensure that the grate 2 does not leak air when it rotates. At the same time, the water in the water seal has a certain cooling effect on the collected hot charcoal blocks and also has a certain dust removal effect on the charcoal recovery process. There are no special requirements for the water quality used for water sealing. Ash slag washing water, cooling water or reclaimed water from other systems can be used.

[0046] Water for water sealing is also required inside the annular sleeve 10 and in the pit connecting the three-way air duct 11. This ensures that the rotation of the rotary grate does not affect the ash discharge while supplying air, and also provides a certain degree of explosion-proof effect.

[0047] Although the present invention has been described in detail above with general descriptions and specific embodiments, some modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

[0048] The terms such as "upper," "lower," "left," "right," and "middle" used in this specification are merely for clarity of description and are not intended to limit the scope of implementation of this utility model. Any changes or adjustments to their relative relationships, without substantially altering the technical content, shall also be considered within the scope of implementation of this utility model.

Claims

1. A biomass gasification furnace grate device, characterized in that, The system includes a grate (2), an ash basin (3), a base (4), a support (9), a three-way air duct (11), a blower (12), and a drive mechanism. The grate (2) is rotatably installed inside the gasifier and is located at the bottom of the gasifier. A material drop gap is provided between the grate (2) and the gasifier wall (1). Multiple first ash knives (101) are provided on the inner wall of the gasifier wall (1). The multiple first ash knives (101) are arranged in a ring along the axis of the gasifier. The ash basin (3) is located at the bottom of the gasifier, and the ash basin (3) is filled with sealing water. The base (4) is disposed at the bottom of the grate (2), the base (4) is rotatably disposed on the support (9), the driving mechanism is connected to the base (4) in a transmission manner, and the driving mechanism is used to drive the base (4) and the grate (2) to rotate; The grate (2) is tower-shaped, and the three-way air duct (11) is located at the bottom of the support (9). The first port of the three-way air duct (11) is connected to the grate (2), the second port of the three-way air duct (11) is connected to the air outlet of the fan (12), and the third end of the three-way air duct (11) is inserted into the pit, which is equipped with sealing water.

2. The biomass gasification furnace grate device according to claim 1, characterized in that, The grate (2) includes a grate tower (201), a cover (202), a gas chamber (204), and a ventilation pipe (205). The grate tower (201) is conical, the cover (202) is located at the top of the grate tower (201), the gas chamber (204) is inverted conical, the top of the gas chamber (204) is connected to the bottom of the grate tower (201), the top of the ventilation pipe (205) is connected to the bottom of the gas chamber (204), and the bottom of the ventilation pipe (205) is connected to the first end of the three-way air guide pipe (11). The grate tower (201) has multiple air supply layers (203) on its side wall. The air supply layers (203) are annular and are arranged sequentially along the height of the grate tower (201). Each air supply layer (203) is provided with multiple gasification air holes (206), and each gasification air hole (206) is provided with a nozzle (207).

3. The biomass gasification furnace grate device according to claim 2, characterized in that, The nozzle (207) has a circular inlet and a flat outlet.

4. The biomass gasification furnace grate device according to claim 2, characterized in that, The number of air supply layers (203) is 4 to 9.

5. The biomass gasification furnace grate device according to claim 2, characterized in that, The inclination angle of the sidewall of the grate tower (201) is 45° to 65°.

6. The biomass gasification furnace grate device according to claim 2, characterized in that, The ventilation pipe (205) is fitted with an annular sleeve (10). The inner diameter of the annular sleeve (10) is smaller than the diameter of the ventilation pipe (205), and the outer diameter of the annular sleeve (10) is larger than the diameter of the ventilation pipe (205). The inner and outer rings of the annular sleeve (10) are hollow. The bottom end of the ventilation pipe (205) is inserted between the inner and outer rings of the annular sleeve (10). The bottom end of the annular sleeve (10) is sealed. The first end of the three-way air guide pipe (11) passes through the bottom of the annular sleeve (10) and is inserted into the ventilation pipe (205). The annular sleeve (10) is filled with sealing water.

7. The biomass gasification furnace grate device according to claim 1, characterized in that, The base (4) is cylindrical, and a plurality of second ash knives (401) are provided on the outer side wall of the base (4). The plurality of second ash knives (401) are arranged in a ring along the axis of the base (4), and adjacent two second ash knives (401) are staggered vertically. The plurality of second ash knives (401) are all located in the ash basin (3).

8. The biomass gasification furnace grate device according to claim 7, characterized in that, The number of the second gray knife (401) is 2 to 8.

9. The biomass gasification furnace grate device according to claim 1, characterized in that, The ash basin (3) is an inverted cone shape, and a plurality of round steel bars (301) are provided on the inner wall of the ash basin (3). The plurality of round steel bars (301) are arranged in a ring along the axis of the ash basin (3).

10. The biomass gasification furnace grate device according to claim 1, characterized in that, The drive mechanism includes a drive motor (7), a large gear (5) and a small gear (6). The large gear (5) is located at the bottom of the base (4). The large gear (5) is coaxial with the base (4) and is mounted on a rolling bearing (8). The rolling bearing (8) is mounted on the bracket (9). The small gear (6) meshes with the large gear (5), and the output end of the drive motor (7) is connected to the small gear (6) for transmission.

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