Updraft biomass gasification furnace

Abstract

The invention relates to an updraft biomass gasification furnace which comprises a feeding chamber and a gasification chamber, the feeding chamber is positioned above the vaporizing chamber and is communicated with the vaporizing chamber, and an exhaust pipe is arranged on the feeding chamber; the exhaust pipe is in a branch pipe shape, is obliquely arranged and is used for exhausting synthesis gas; a compressed air inlet is formed in the lower end of the vaporizing chamber; the stirrer is arranged in the feeding chamber and the gasification chamber in a penetrating manner, so that uniform dispersion of biomass raw materials is realized through mechanical disturbance, and uniform gasification of the raw materials is ensured. Therefore, not only is the operation more efficient and stable, but also the raw materials are wide in applicability, and the production requirements can be fully met.

Description

Technical Field

[0001] This invention relates to an industrial apparatus, particularly a biomass gasification furnace, specifically an upward-suction biomass gasification furnace. Background Technology

[0002] Biomass energy is the fourth largest energy resource in my country, after coal, oil, and natural gas. It occupies an important position in the energy system and is the only renewable energy source that can be directly converted into gaseous / liquid fuels. Its carbon-neutral characteristics meet the country's requirements for low-carbon development and reduce dependence on fossil fuels.

[0003] Biomass gasifiers generally employ fixed-bed gasifiers and fluidized-bed gasifiers. Fluidized-bed gasifiers are complex, require high investment, and have strict requirements on feed particle size. Fixed-bed gasifiers, on the other hand, have a simpler structure, lower feed requirements, and a wider range of applications. Fixed-bed gasifiers are classified into top-suction and bottom-suction types based on the airflow direction. Currently, top-suction gasifiers are more commonly used. Their main components include a feed inlet, furnace chamber, grate, and ash chamber. Biomass is supplied from the top feed inlet, while the gasifying agent enters through the bottom inlet. Inside the furnace chamber, the agent contacts the high-temperature biomass and undergoes a combustion reaction. The resulting ash is collected in the ash chamber through the grate.

[0004] However, conventional upward-suction gasifiers often have a constricted furnace, which can easily cause material accumulation and make it difficult for the material inside the furnace to be gasified evenly. At the same time, their syngas pipelines are mostly curved, which can easily lead to blockages and incomplete reactions due to the accumulation of tar formed during combustion. They are also difficult to handle materials with high moisture content, high ash content, and a tendency to scale.

[0005] Therefore, improvements are urgently needed to better meet production demands. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by providing an upward-suction biomass gasification furnace that is not only highly efficient and stable in operation, but also has a wide range of raw material applicability, which can fully meet production needs.

[0007] The technical solution of this invention is: An upward-suction biomass gasifier includes a feeding chamber and a gasification chamber. The feeding chamber is located above the gasification chamber and is interconnected with it. An exhaust pipe is provided on the feeding chamber. The exhaust pipe is branch-shaped and obliquely arranged to discharge syngas. A compressed air inlet is provided at the lower end of the gasification chamber. The gasifier also includes a stirrer, which is installed through the feeding chamber and the gasification chamber to achieve uniform dispersion of biomass raw materials through mechanical agitation and ensure uniform gasification of the raw materials.

[0008] Furthermore, both the feeding chamber and the gasification chamber are cylindrical straight tubes; the diameter of the feeding chamber is smaller than that of the gasification chamber.

[0009] Furthermore, the lower end of the gasification chamber is provided with a perforated ash discharge baffle, which is connected to the ash discharge / ignition chamber; the compressed air inlet is located on the side wall of the ash discharge / ignition chamber.

[0010] Furthermore, the bottom of the ash discharge / ignition chamber is provided with an ash discharge port.

[0011] Furthermore, the angle between the exhaust pipe and the side wall of the feed chamber is 30~45°.

[0012] Furthermore, the agitator includes a main shaft; the main shaft is straight and has spiral blades on it, with its upper end connected to a motor and its lower end adjacent to the ash discharge baffle; the motor is located above the feed chamber.

[0013] Furthermore, the interior of the gasification chamber is divided into a drying zone, a pyrolysis zone, and a combustion zone from top to bottom according to temperature; the lower end of the blade is located in the drying zone.

[0014] Furthermore, it also includes a scraper; the scraper is triangular, with its apex connected to the main shaft, and the length of its base is approximately equal to the diameter of the ash discharge baffle; both ends of the base are provided with downward-protruding blades; the blades are short plates, with their lower ends close to the ash discharge baffle.

[0015] Furthermore, it also includes a feeding structure, which is L-shaped, comprising a vertically placed hopper and a horizontally placed feeding pipe; the upper end of the hopper is closed, and its lower end is connected to one end of the feeding pipe; the other end of the feeding pipe is connected to the feeding chamber; a screw conveyor is installed inside the feeding pipe.

[0016] The beneficial effects of this invention are: 1. The gasification chamber has no narrowing, allowing the raw material to flow downwards without obstruction under gravity, completely eliminating accumulation and improving carbon conversion rate.

[0017] 2. By setting up silos and screw conveyors, it is convenient to transport raw materials and enable the system to operate continuously for a short period of time.

[0018] 3. The exhaust pipe is a straight pipe, which allows tar to drip back into the gasifier instead of accumulating at bends, thus avoiding pressure increases caused by the inability of furnace gas to be discharged.

[0019] 4. By setting up a stirrer, the biomass raw materials are mechanically disturbed to achieve uniform dispersion, which not only ensures full contact with the high-temperature reaction gas, but also effectively prevents the raw materials from adhering to the furnace wall. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the present invention.

[0021] Figure 2 This is a diagram of a mixer and a scraper.

[0022] Among them, 1-exhaust pipe; 2-feeding chamber; 3-gasification chamber; 4-scraper; 41-blade; 5-compressed air inlet; 6-ash discharge port; 7-ash discharge / ignition chamber; 8-ash discharge baffle; 9-agitator; 91-blade; 92-main shaft; 10-screw conveyor; 11-hopper; 12-feeding pipe; Ⅰ-drying zone; Ⅱ-pyrolysis zone; Ⅲ-combustion zone. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0024] like Figure 1 and 2 As shown.

[0025] An upward-suction biomass gasifier includes a feeding chamber 2, a gasification chamber 3, a feeding structure, and a stirrer 9.

[0026] Both the feeding chamber 2 and the gasification chamber 3 are cylindrical straight tubes, with the diameter of the feeding chamber being smaller than that of the gasification chamber. The feeding chamber 2 is located above the gasification chamber 3 and is interconnected, allowing biomass feedstock to easily enter the gasification chamber from the feeding chamber. Preferably, the gasification chamber 3 is divided into a drying zone I, a pyrolysis zone II, and a combustion zone III according to temperature from top to bottom, providing a reference for the installation of other structures. In this embodiment, the drying zone I is 250°C, the pyrolysis zone II is 600°C, and the combustion zone III is 1100°C.

[0027] The feed chamber 2 is equipped with an exhaust pipe 1. The exhaust pipe 1 is branch-shaped and obliquely arranged to discharge the synthesis gas. Preferably, the angle between the exhaust pipe 1 and the side wall of the feed chamber 2 is 30~45°, which facilitates installation and use.

[0028] The lower end of the gasification chamber 3 is provided with a perforated ash discharge baffle 8, which is connected to the ash discharge / ignition chamber 7, so that the ash and slag after the raw material combustion can fall into the ash discharge / ignition chamber 7 below through the ash discharge baffle 8. The ash discharge / ignition chamber 7 has a compressed air inlet on its side wall, so that compressed air can be introduced into the gasification chamber to meet the requirements of raw material combustion. At the same time, the bottom of the ash discharge / ignition chamber 7 has an ash discharge port 6 to discharge the ash and slag.

[0029] The feeding structure is L-shaped, including a vertically placed hopper 11 and a horizontally placed feeding pipe 12. The upper end of the hopper 11 is closed, and its lower end is connected to one end of the feeding pipe 12. The other end of the feeding pipe 12 is connected to the feeding chamber 2. A screw conveyor 10 is installed inside the feeding pipe 12. In use, wood chips can be selected as raw material, pre-treated and stored in the hopper, and then fed into the feeding chamber along the feeding pipe by the screw conveyor.

[0030] The agitator 9 includes a main shaft 92 and blades 91. The main shaft 92 is a straight rod that runs through the feed chamber 2 and the gasification chamber 3. Its upper end is connected to a motor installed above the feed chamber 1, and its lower end is near the ash discharge baffle 8. The blades 91 are helical and are installed around the upper part of the main shaft. Their lower end is located in the drying zone I, and their upper end is not lower than the connection between the feed pipe 12 and the feed chamber 2. Thus, the agitator 9 can mechanically agitate the biomass raw materials, thereby uniformly dispersing the raw materials and ensuring uniform gasification.

[0031] Furthermore, a scraper 4 is provided at the lower end of the main shaft 92. This scraper 4 is triangular, with its apex connected to the main shaft, and the length of its base is approximately equal to the diameter of the ash discharge baffle 8. Downward-protruding blades 41 are provided at both ends of this base. Each blade 41 is short and its lower end is close to the ash discharge baffle 8. Thus, the scraper can rotate with the main shaft to push the ash and slag, allowing it to efficiently pass through the ash discharge baffle and fall into the ash discharge / ignition chamber.

[0032] The operation process of this invention is as follows: The raw materials descend uniformly under the action of a stirrer, undergoing a gradient conversion process of drying, pyrolysis, and combustion. In the drying zone, the biomass feedstock is heated by a counter-current upward-flowing high-temperature syngas stream, where moisture evaporates and is discharged with the rising gas, creating suitable conditions for subsequent pyrolysis and combustion reactions. As the feedstock descends, the temperature gradient gradually increases.

[0033] Meanwhile, compressed air from outside enters the gasifier through the ash discharge / ignition chamber at the bottom, completing the start-up and ignition operation. In the combustion zone, air and biomass undergo a violent oxidation reaction.

[0034] When the raw materials are completely burned, the released heat provides energy for the pyrolysis reaction and generates products such as carbon dioxide and water vapor. These gases and heat flow counter-currently to the pyrolysis zone, reacting with the biomass and causing the release of volatiles (CO, H2, CH4, etc.), while simultaneously achieving preliminary cracking of the tar, reducing the tar content to below 50 mg / Nm³. Finally, the syngas is discharged through the combined exhaust pipe and enters the downstream process.

[0035] The ash produced by biomass gasification falls into the ash discharge / ignition chamber through the ash discharge baffle at the bottom of the gasification chamber and is then discharged through the ash discharge port.

[0036] Advantages of this invention: 1. The gasification chamber has no narrowing, allowing the raw material to flow downwards without obstruction under gravity, completely eliminating accumulation and improving carbon conversion rate.

[0037] 2. By setting up silos and screw conveyors, it is convenient to transport raw materials and enable the system to operate continuously for a short period of time.

[0038] 3. The exhaust pipe is a straight pipe, which allows tar to drip back into the gasifier instead of accumulating at bends, thus avoiding pressure increases caused by the inability of furnace gas to be discharged.

[0039] 4. By setting up a stirrer, the biomass raw materials are mechanically disturbed to achieve uniform dispersion, which not only ensures full contact with the high-temperature reaction gas, but also effectively prevents the raw materials from adhering to the furnace wall.

[0040] All parts not covered in this invention are the same as or can be implemented using existing technologies.

Claims

1. An upward-suction biomass gasifier, comprising a feeding chamber and a gasification chamber; characterized in that, The feed chamber is located above the gasification chamber and is interconnected with it. It is equipped with an exhaust pipe. The exhaust pipe is branched and obliquely arranged to discharge syngas. The lower end of the gasification chamber is equipped with a compressed air inlet. It also includes a stirrer, which is installed through the feed chamber and the gasification chamber to achieve uniform dispersion of biomass raw materials through mechanical disturbance and ensure uniform gasification of raw materials.

2. The upward-suction biomass gasifier according to claim 1, characterized in that, Both the feeding chamber and the gasification chamber are cylindrical straight tubes; the diameter of the feeding chamber is smaller than that of the gasification chamber.

3. The upward-suction biomass gasification furnace according to claim 1, characterized in that, The lower end of the gasification chamber is provided with a perforated ash discharge baffle, which is connected to the ash discharge / ignition chamber; the compressed air inlet is located on the side wall of the ash discharge / ignition chamber.

4. The upward-suction biomass gasifier according to claim 3, characterized in that, The bottom of the ash discharge / ignition chamber is equipped with an ash discharge port.

5. The upward-suction biomass gasifier according to claim 1, characterized in that, The angle between the exhaust pipe and the side wall of the feed chamber is 30~45°.

6. The upward-suction biomass gasifier according to claim 3, characterized in that, The agitator includes a main shaft; the main shaft is straight and has spiral blades on it, with its upper end connected to a motor and its lower end adjacent to the ash discharge baffle; the motor is located above the feed chamber.

7. The upward-suction biomass gasifier according to claim 6, characterized in that, The gasification chamber is divided into a drying zone, a pyrolysis zone, and a combustion zone from top to bottom according to temperature; the lower end of the blade is located in the drying zone.

8. The upward-suction biomass gasifier according to claim 6, characterized in that, It also includes a scraper; the scraper is triangular, with its apex connected to the main shaft, and the length of its base is approximately equal to the diameter of the ash discharge baffle; the two ends of the base are respectively provided with downward protruding blades; the blades are short plates, with their lower ends close to the ash discharge baffle.

9. The upward-suction biomass gasifier according to claim 1, characterized in that, It also includes a feeding structure, which is L-shaped, comprising a vertically placed hopper and a horizontally placed feeding pipe; the upper end of the hopper is closed, and its lower end is connected to one end of the feeding pipe; the other end of the feeding pipe is connected to the feeding chamber; a screw conveyor is installed inside the feeding pipe.

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