A biomass gasifier

Abstract

This invention discloses a biomass gasification furnace, belonging to the field of biomass gasification technology. It includes a tank body with an internal drying layer, pyrolysis layer, reduction layer, and oxidation layer, converting biomass raw materials into combustible gas through four reaction stages. The tank body contains a double-layered reaction cylinder: an outer heat-conducting cylinder and an inner permeable cylinder, with a gas storage chamber between them for collecting combustible gas. The heat-conducting cylinder has good thermal conductivity, while the permeable cylinder allows gas to pass through smoothly. High-temperature gas is injected around the heat-conducting cylinder to transfer heat to the drying, pyrolysis, and reduction layers. External heating is achieved through a heat transfer chamber in the tank body's interlayer and a spiral channel in the heat-conducting cylinder; hot gas enters the heat transfer chamber and the outlet chamber from the bottom of the tank body to heat the interior of the reaction cylinder. Internal heating is achieved through vent holes and a ventilation mesh inside the rotating rod; hot gas is transported to the drying, pyrolysis, and reduction layers to accelerate the reaction rate.

Description

Technical Field

[0001] This invention relates to the field of biomass gasification technology, specifically to a biomass gasification furnace. Background Technology

[0002] In the field of biomass conversion technology, gasification plays a crucial role in efficiently converting biomass feedstocks into high-quality combustible gases. The performance of the biomass gasifier has a decisive impact on the efficiency of the entire gasification process and the quality of the final product. However, traditional biomass gasifier designs have certain limitations in terms of thermal energy utilization efficiency and reaction condition control.

[0003] Traditional designs typically install heating devices only on the outer shell. This outside-to-inside heating method often results in uneven heat distribution within the furnace, with the external heating level significantly higher than the internal heating level. Although this design improves the performance of the gasifier to some extent, it still faces many technical challenges, such as uneven heat transfer, low gas circulation efficiency, and complex system maintenance.

[0004] Therefore, the present invention provides a biomass gasification furnace that can solve the above-mentioned problems. Summary of the Invention

[0005] To address the aforementioned technical shortcomings, the purpose of this invention is to provide a biomass gasification furnace that can achieve better heating performance.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: The present invention provides a biomass gasification furnace, including a tank body, wherein the inner cavity of the tank body is provided with a drying layer, a pyrolysis layer, a reduction layer and an oxidation layer, and the top of the tank body is provided with a feed inlet and the bottom is provided with a discharge outlet.

[0007] The tank is equipped with a reaction cylinder inside, which is fixed to the inner wall of the tank. The bottom of the reaction cylinder is open. The reaction cylinder has a double-layer structure, with the outer layer being a heat-conducting cylinder and the inner layer being a ventilating cylinder. A gas storage chamber is provided between the heat-conducting cylinder and the ventilating cylinder. An exhaust pipe is connected to the upper end of the gas storage chamber. The exhaust pipe extends through the tank to the outside of the gasifier.

[0008] The tank has a rotating rod that rotates through its center, and a spiral auger is installed at the bottom end of the rotating rod. The spiral auger is rotatably installed at the discharge port.

[0009] Preferably, the oxide layer is disposed at the bottom outlet of the reaction cylinder, and an oxygen inlet pipe is provided on one side of the oxide layer, the oxygen inlet pipe extending through the tank body to the outside of the gasifier.

[0010] Preferably, a heat transfer chamber is provided in the interlayer of the tank body, and the bottom of the heat transfer chamber is provided with an opening, which communicates with the internal cavity of the tank body.

[0011] Preferably, the rotating rod has a ventilation hole inside, the lower end of which is connected to a hot air supply device, and the rotating rod has multiple ventilation nets on its outside. The drying layer, pyrolysis layer and reduction layer are each provided with a ventilation net.

[0012] Preferably, a circulation pipe is fixed on the side wall of the tank, one end of the circulation pipe is connected to the lower end of the inner cavity of the tank, and the other end is rotatably connected to a rotating rod. A sealing head is provided between the lower end of the rotating rod and the circulation pipe, and a circulation pump is fixed on the circulation pipe.

[0013] Preferably, a sealing ring is provided on the inner bottom side of the heat-conducting cylinder, and the sealing ring is connected to the venting cylinder.

[0014] Preferably, the upper end of the heat-conducting cylinder is fixed to the inner wall of the tank, and an air outlet chamber is provided between the heat-conducting cylinder and the tank. The bottom of the air outlet chamber is connected to the inner cavity of the tank, and an air outlet pipe is installed at the upper end of the air outlet chamber.

[0015] Preferably, a gas guide plate is fixed to the outside of the heat-conducting cylinder, and the gas guide plate is spiral-shaped and forms a spiral channel inside the gas outlet cavity.

[0016] Preferably, a cover is fixed to the upper end of the tank, a drive motor is fixed to the cover, the output shaft of the drive motor passes through the cover and is connected to the rotating rod, and a feed pipe is provided on one side of the cover.

[0017] The beneficial effects of this invention are as follows:

[0018] By combining external heating (heat generated by the oxide layer and the heat transfer chamber) with internal heating (venting holes in the rotating rod and the circulation pipe system), the temperature in the drying layer, pyrolysis layer, reduction layer and oxide layer is kept stable and uniform. This not only accelerates the conversion process of biomass raw materials, but also improves the efficiency of combustible gas generation.

[0019] The double-layer structure of the reaction chamber (heat-conducting chamber and gas-permeable chamber) effectively isolates the high-temperature gas from the reactants, while ensuring efficient heat transfer and smooth gas flow. This design allows each reaction layer to operate under optimal temperature and gas conditions, thereby improving overall gasification efficiency and product quality.

[0020] The combination of the circulating pump and the sealing head ensures a continuous and stable supply of heat and effective gas circulation. This not only guarantees a constant internal temperature for the gasifier but also prevents unnecessary heat loss and gas leakage. Attached Figure Description

[0021] Figure 1 This is an internal view of the tank.

[0022] Figure 2 This is a three-dimensional view of the tank.

[0023] Figure 3 This is a structural diagram of the reaction vessel.

[0024] Figure 4 This is a connection diagram of the rotating rod and the auger.

[0025] Figure 5 This is a cross-sectional view of the tank.

[0026] Figure 6 for Figure 1 A in the enlarged view.

[0027] In the diagram: 1. Tank body, 2. Drying layer, 3. Pyrolysis layer, 4. Reduction layer, 5. Oxidation layer, 6. Discharge port, 7. Reaction cylinder, 71. Heat conduction cylinder, 72. Ventilation cylinder, 73. Gas storage chamber, 74. Gas guide plate, 8. Exhaust pipe, 9. Rotating rod, 91. Ventilation net, 10. Feed pipe, 11. Gas outlet chamber, 12. Gas outlet pipe, 13. Oxygen inlet pipe, 14. Circulation pipe, 15. Heat transfer chamber, 16. Circulation pump, 17. Cover cylinder, 18. Spiral auger. Detailed Implementation

[0028] The present invention is illustrated below with specific embodiments, but these are not intended to limit the invention.

[0029] Example 1

[0030] like Figures 1-6 As shown in this embodiment, a biomass gasification furnace is provided, including a tank 1. The inner cavity of the tank 1 is provided with a drying layer 2, a pyrolysis layer 3, a reduction layer 4, and an oxidation layer 5. In the biomass gasification furnace, the reaction process of the material passes through the drying layer 2, the pyrolysis layer 3, the reduction layer 4, and the oxidation layer 5 from top to bottom. The reaction stages corresponding to each layer are as follows:

[0031] First, the material enters drying layer 2, which is called the drying stage. In this layer, the raw material is subjected to the high temperature inside the furnace and begins the drying process. Its main purpose is to remove moisture from the raw material, preparing it for the subsequent pyrolysis reaction. Next, the material enters pyrolysis layer 3, which is called the pyrolysis stage. As the temperature further increases, the raw material begins to undergo a pyrolysis reaction, decomposing into smaller molecules. These decomposition products include coke, combustible gases (such as carbon monoxide and hydrogen), and tar. Then, the material enters reduction layer 4, which is called the reduction stage. In this layer, the coke reacts with the gasifying agent (such as air, steam, or carbon dioxide) under high-temperature, oxygen-deficient conditions. The main purpose of this reaction is to generate combustible gases such as carbon monoxide and hydrogen, which are among the main products of biomass gasification furnaces. Finally, the material enters oxidation layer 5, which is called the oxidation stage. In this layer, some of the coke and combustible gases react with oxygen, releasing a large amount of heat. This heat is used not only to maintain the high-temperature environment inside the furnace but also to provide the necessary energy for the entire gasification process. In summary, the biomass gasifier converts biomass feedstock into combustible gas through reaction stages such as drying, pyrolysis, reduction, and oxidation, achieving efficient utilization of biomass resources and environmental emission reduction. The tank 1 has an inlet at the top and an outlet at the bottom. The inlet is the starting point for feedstock entering the biomass gasifier. Feedstock such as agricultural waste and forestry residues, such as straw, sawdust, and rice husks, will sequentially pass through the drying layer 2, pyrolysis layer 3, reduction layer 4, and oxidation layer 5 once they enter the tank 1. These four reaction layers work together to efficiently convert biomass feedstock into combustible gas.

[0032] A cover cylinder 17 is fixed to the upper end of the tank body 1. A drive motor is fixed on the cover cylinder 17. The output shaft of the drive motor passes through the cover cylinder 17 and is connected to the rotating rod 9. The motor drives the rotating rod 9 to rotate, and the spiral auger 18 fixed on the rotating rod 9 will rotate along with it. A feed pipe 10 is provided on one side of the cover cylinder 17. The feed pipe 10 can inject the substance to be reacted into the tank body 1 to participate in the reaction.

[0033] The tank 1 contains a reaction cylinder 7, which is fixed to the inner wall of the tank 1. The upper end of the reaction cylinder 7 is flared, and the outer edge of this flared part is firmly installed on the inner wall of the tank 1. A certain space gap is intentionally maintained between the main body of the reaction cylinder 7 and the tank 1, and the bottom of the reaction cylinder 7 is an open structure. The drying layer 2 is located at the upper end of the reaction cylinder 7, the pyrolysis layer 3 and the reduction layer 4 are both located inside the reaction cylinder 7, and the oxidation layer 5 is located at the lower outlet of the reaction cylinder 7. The reaction cylinder 7 has a double-layer structure. The outer layer of the reaction cylinder 7 is a heat-conducting cylinder 71, and the inner layer is a venting cylinder 72. A gas storage chamber 73 is provided between the heat-conducting cylinder 71 and the venting cylinder 72. The upper end of the gas storage chamber 73 is connected to an exhaust pipe 8, which extends through the tank 1 to the outside of the gasifier. The heat-conducting cylinder 71 has excellent thermal conductivity, while the venting cylinder 72 has good air permeability. High-temperature gas is injected around the heat-conducting cylinder 71, effectively transferring heat to the drying layer 2, pyrolysis layer 3, and reduction layer 4. Simultaneously, the venting cylinder 72, with its excellent permeability, allows combustible gases generated from the pyrolysis layer 3 and reduction layer 4 to pass smoothly. These combustible gases then pass through the venting cylinder 72 and enter the gas storage chamber 73. Inside the gas storage chamber 73, the higher-temperature gas naturally rises and is eventually discharged and collected through the exhaust pipe 8.

[0034] The tank body 1 has a rotating rod 9 that rotates through its center. A spiral auger 18 is installed at the bottom end of the rotating rod 9. The spiral auger 18 is rotatably installed at the discharge port 6. The rotation of the rotating rod 9 can drive the rotation of the spiral auger 18. When the spiral auger 18 rotates, it can discharge the solid waste from the oxide layer 5 into the tank body 1. When the spiral auger 18 is fixed, the waste will not be discharged.

[0035] Example 2

[0036] like Figures 1-6 As shown, based on Embodiment 1, this embodiment provides external heating functions for the drying layer 2, pyrolysis layer 3, and reduction layer 4, as detailed below:

[0037] An oxide layer 5 is located at the bottom outlet of the reaction cylinder 7. An oxygen inlet pipe 13 is provided on one side of the oxide layer 5. The oxygen inlet pipe 13 extends through the tank body 1 to the outside of the gasifier. During the oxidation stage, some of the gas reacts with the oxygen entering through the oxygen inlet pipe 13 to generate heat, which provides the necessary thermal energy for the preceding drying, pyrolysis, and reduction stages. At the same time, the heat generated by the oxidation reaction also helps to maintain the temperature inside the gasifier.

[0038] A heat transfer chamber 15 is provided in the interlayer of the tank body 1. The bottom of the heat transfer chamber 15 has an opening, which communicates with the internal cavity of the tank body 1. During the oxidation stage, the heat generated can smoothly enter the interior of the heat transfer chamber 15 through the opening at the bottom. This heat is then effectively transferred to the upper region of the tank body 1, realizing a heat transfer process from the outside to the inside, ensuring that the interior of the tank body 1 maintains the required temperature level. It is worth noting that the heat source here is not limited to the heat naturally generated during the oxidation stage; hot air can also be introduced from the outside as a supplement if needed. The key is to ensure that the interior of the tank body 1 reaches and maintains appropriate temperature conditions.

[0039] The upper end of the heat-conducting cylinder 71 is fixed to the inner wall of the tank 1. An outlet chamber 11 is provided between the heat-conducting cylinder 71 and the tank 1. The bottom of the outlet chamber 11 communicates with the inner cavity of the tank 1, and an outlet pipe 12 is installed at the upper end of the outlet chamber 11. Hot gas flows in from the bottom opening of the outlet chamber 11, primarily to heat the interior of the reaction cylinder 7, especially the pyrolysis layer 3 and the reduction layer 4. This heating process, combined with the heat in the interlayer of the tank 1, effectively accelerates the rate at which combustible gases are generated in the pyrolysis layer 3 and the reduction layer 4. Simultaneously, the outlet pipe 12, located at the upper end, is responsible for discharging the hot gas. This design promotes the circulation of hot gas, thereby ensuring the continuous stability of the internal temperature of the tank 1.

[0040] A gas guide plate 74 is fixed to the outside of the heat conduction cylinder 71. The gas guide plate 74 is spiral and forms a spiral channel inside the gas outlet chamber 11. Hot gas enters the spiral channel from the bottom and rises slowly inside the spiral channel. During the spiral ascent, the gas will transfer the temperature to the inside of the tank 1.

[0041] Example 3

[0042] like Figures 1-6 As shown, based on Embodiment 1 and Embodiment 2, this embodiment provides internal heating functions for the drying layer 2, pyrolysis layer 3, and reduction layer 4, as detailed below:

[0043] The rotating rod 9 has internal ventilation holes, the lower ends of which are connected to a hot air supply device. Multiple ventilation meshes 91 are located on the outside of the rotating rod 9. Each of the drying layer 2, pyrolysis layer 3, and reduction layer 4 is equipped with a corresponding ventilation mesh 91. The ventilation hole design aims to effectively transport hot air to the drying layer 2, pyrolysis layer 3, and reduction layer 4, achieving uniform heat distribution from the inside to these layers. This mechanism not only promotes rapid drying of the material inside the drying layer 2 but also accelerates the generation rate of combustible gases in the pyrolysis layer 3 and reduction layer 4. Simultaneously, its synergistic effect with the external air outlet 11 and heat transfer chamber 15 further enhances the heating effect, ensuring efficient heat transfer from the inside to the outside and improving the overall thermal efficiency of the system.

[0044] A circulation pipe 14 is fixed to the side wall of tank 1. One end of the circulation pipe 14 is connected to the lower end of the inner cavity of tank 1, and the other end is rotatably connected to a rotating rod 9. A sealing head is provided between the lower end of the rotating rod 9 and the circulation pipe 14. A circulation pump 16 is fixed to the circulation pipe 14. The heat in the inner hole of the rotating rod 9 originates from the cavity inside tank 1. This heat supply mechanism ensures continuous and stable heat. Driven by the circulation pump 16, the hot gas in tank 1 is effectively extracted and transported to the inside of the rotating rod 9 through the circulation pipe 14. Subsequently, this hot gas is further distributed to the drying layer 2, the pyrolysis layer 3, and the reduction layer 4, realizing precise heat transfer and utilization. This process not only improves the efficiency of heat utilization but also ensures that each layer receives sufficient heat support, thereby promoting the smooth progress of drying, pyrolysis, and reduction reactions.

[0045] A sealing ring is provided on the inner bottom of the heat conduction cylinder 71. The sealing ring is connected to the vent cylinder 72, and the combustible gas smoothly enters the gas storage chamber 73 through the vent hole.

[0046] Working principle:

[0047] Biomass raw materials (such as straw, sawdust, etc.) enter the tank 1 through the feed pipe 10 and pass through the drying layer 2, pyrolysis layer 3, reduction layer 4 and oxidation layer 5 in sequence.

[0048] In drying layer 2, the raw materials are subjected to the high temperature inside the furnace and begin the drying process to remove excess moisture, preparing them for subsequent reactions. As the temperature further increases, the raw materials enter pyrolysis layer 3, where a pyrolysis reaction begins, decomposing them into products such as coke, combustible gases, and tar. In reduction layer 4, the coke and gasifying agent undergo a reduction reaction under high-temperature and oxygen-deficient conditions, generating combustible gases such as carbon monoxide and hydrogen.

[0049] Some of the coke and combustible gas enter the oxidation layer 5, where they undergo an oxidation reaction with oxygen, releasing a large amount of heat. This heat not only maintains the high-temperature environment inside the furnace but also provides the necessary thermal energy for the preceding reaction layer.

[0050] The heat generated by the oxide layer 5 is transferred to the interior of the tank 1 through the heat transfer chamber 15 and the gas outlet chamber 11, specifically for heating the pyrolysis layer 3 and the reduction layer 4. At the same time, the vent hole of the rotating rod 9 and the circulation pipe 14 system realize the internal transfer of heat and the circulation of gas, further enhancing the heating effect and gasification efficiency.

[0051] Combustible gases are collected centrally through the gas storage chamber 73 and the exhaust pipe 8; waste is discharged from the tank 1 through the screw conveyor 18 when the rotating rod 9 rotates.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate and not limit the technical solutions of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention without departing from the spirit and scope of the present invention. Any modifications or partial substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A biomass gasification furnace, comprising a tank (1), wherein the inner cavity of the tank (1) is provided with a drying layer (2), a pyrolysis layer (3), a reduction layer (4) and an oxidation layer (5), and the top of the tank (1) is provided with a feed inlet and the bottom is provided with a discharge outlet (6), characterized in that... ； The tank (1) is equipped with a reaction cylinder (7) inside. The reaction cylinder (7) is fixed on the inner wall of the tank (1). The bottom of the reaction cylinder (7) is an open structure. The reaction cylinder (7) is a double-layer structure. The outer layer of the reaction cylinder (7) is a heat-conducting cylinder (71), and the inner layer is a ventilating cylinder (72). A gas storage chamber (73) is provided between the heat-conducting cylinder (71) and the ventilating cylinder (72). An exhaust pipe (8) is connected to the upper end of the gas storage chamber (73). The exhaust pipe (8) extends through the tank (1) to the outside of the gasifier. Among them, the center of the tank (1) is rotatably penetrated by a rotating rod (9), and a spiral auger (18) is installed at one end of the bottom of the rotating rod (9). The spiral auger (18) is rotatably installed at the discharge port (6). The oxide layer (5) is located at the bottom outlet of the reaction cylinder (7), and an oxygen inlet pipe (13) is provided on one side of the oxide layer (5). The oxygen inlet pipe (13) passes through the tank body (1) and extends to the outside of the gasifier. The tank (1) has a heat transfer chamber (15) in its interlayer. The bottom of the heat transfer chamber (15) has an opening and is connected to the internal cavity of the tank (1) through the opening. The upper end of the heat-conducting cylinder (71) is fixed on the inner wall of the tank (1). An air outlet chamber (11) is provided between the heat-conducting cylinder (71) and the tank (1). The bottom of the air outlet chamber (11) is connected to the inner cavity of the tank (1). An air outlet pipe (12) is installed at the upper end of the air outlet chamber (11). The heat-conducting cylinder (71) is fixed with an air guide plate (74), which is spiral in shape and forms a spiral channel inside the air outlet cavity (11).

2. The biomass gasification furnace according to claim 1, characterized in that, The rotating rod (9) has a ventilation hole inside, and the lower end of the ventilation hole is connected to the hot air supply device. The rotating rod (9) has multiple ventilation nets (91) on its outside. The drying layer (2), pyrolysis layer (3) and reduction layer (4) are all provided with ventilation nets (91).

3. A biomass gasification furnace according to claim 2, characterized in that, A circulation pipe (14) is fixed on the side wall of the tank (1). One end of the circulation pipe (14) is connected to the lower end of the inner cavity of the tank (1), and the other end is rotatably connected to the rotating rod (9). A sealing head is provided between the lower end of the rotating rod (9) and the circulation pipe (14). A circulation pump (16) is fixed on the circulation pipe (14).

4. A biomass gasification furnace according to claim 1, characterized in that, The heat-conducting cylinder (71) has a sealing ring on the inner side of its bottom, and the sealing ring is connected to the vent cylinder (72).

5. A biomass gasification furnace according to claim 1, characterized in that, The upper end of the tank (1) is fixed with a cover cylinder (17), and a drive motor is fixed on the cover cylinder (17). The output shaft of the drive motor passes through the cover cylinder (17) and is connected to the rotating rod (9). A feed pipe (10) is provided on one side of the cover cylinder (17).

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