An improved updraft biomass gasification device

Abstract

This invention discloses an improved updraft biomass gasification device, comprising an outer wall of the furnace body, a feed pipe, an internal baffle, a solid collection water tank, an air inlet pipe, and a grate. An installation hole is located at the center of the top of the outer wall of the furnace body, and a syngas outlet is located at the top. The feed pipe is inserted into the installation hole. The solid collection water tank is installed at the lower part of the outer wall of the furnace body. The air inlet pipe passes through the solid collection water tank, with a grate installed at one end and the other end connected to the outside. The end of the feed pipe located inside the outer wall of the furnace body is inclined, and an internal baffle is located around the inclined surface. The internal baffle has an arc-shaped structure and is arranged along the plane of the inclined surface to form a bed syngas outlet. This invention improves upon the traditional updraft biomass gasifier to solve the problem of high tar content in traditional updraft gasifiers, while effectively increasing the proportion of hydrogen and carbon monoxide in the outlet syngas, thus improving syngas quality.

Description

Technical Field

[0001] This invention relates to the field of environmentally friendly stove equipment technology, and in particular to an improved top-suction fixed-bed biomass gasification device. Background Technology

[0002] With the increasing use of high-carbon fossil fuels, the growing problem of climate change has garnered widespread attention. Zero-carbon renewable energy, represented by biomass energy, is the future direction of energy development. Compared to other renewable energy sources, biomass energy, in addition to providing electricity, can also provide a variety of industrial products such as high-value fuel gas, biodiesel, high-quality chemicals, high-grade steam, and biochar fertilizer feedstock, serving multiple sectors including people's livelihood, transportation, agriculture, industry, and building heating. It occupies an important position in my country's future energy utilization. Biomass energy utilization technologies mainly fall into two categories: thermochemical conversion and biochemical conversion. Among them, thermochemical methods are more efficient, and biomass gasification is one of the most important thermochemical treatment methods.

[0003] Updraft fixed-bed biomass gasifiers are commonly used biomass gasification reactors in industry. In an updraft gasifier, the material moves downwards while the gas moves upwards, with the material sequentially undergoing drying, pyrolysis, reduction, and oxidation stages. High-temperature gas flows counter-currently with the material; after being heated, dried, and pyrolyzed by the high-temperature gas, the material primarily undergoes a heterogeneous combustion reaction between residual solids and oxygen at the bottom of the furnace. Updraft gasifiers have high thermal efficiency and relatively relaxed requirements for raw materials, and they also produce a high hydrogen content in the syngas. However, they suffer from a high tar content in the syngas. This patent improves upon the traditional updraft gasifier to address the high tar content in the syngas and simultaneously improve its quality.

[0004] Patent application number 202011333813.4, entitled "An Upward Suction Fixed Bed Biomass Gasifier," proposes an upward suction fixed bed biomass gasifier. The gasifier mainly includes a bucket elevator, a feeding device, a main gasifier furnace, a grate, and a tar recovery device. While this patent improves the feeding equipment and reduces clogging during the feeding process, its main furnace structure is the same as that of traditional upward suction gasifiers, and the problem of high tar content remains unresolved.

[0005] The patent application number 201420483698.2, entitled "A Top-Suction Biomass Gasifier with Central Gas Exit," proposes a fixed-bed top-suction gasifier with central gas exit to improve the quality of the produced combustible gas. In this patent, biomass is fed from the top, with air intake and ash discharge from the bottom. However, the residence time of the gasifying agent in this device is relatively short, which may lead to incomplete gasification and lower syngas quality. Furthermore, the tar problem is not well resolved.

[0006] As can be seen, in traditional top-suction gasifiers, biomass is added from the top of the furnace. The biomass undergoes drying, pyrolysis, reduction, and oxidation processes sequentially. High-temperature gas flows counter-currently with the material, which is then heated, dried, and pyrolyzed by the high-temperature gas. At the bottom of the furnace, the main process is a heterogeneous combustion reaction between residual solid carbon and oxygen. Based on operational experience and theoretical analysis, its specific disadvantages are as follows:

[0007] 1. Syngas has a high tar content.

[0008] In existing top-suction fixed-bed gasifiers, the tar produced during the pyrolysis stage does not flow out of the outlet through high-temperature decomposition, resulting in a high tar content in the syngas, which affects the quality of combustible gas and can further lead to a reduction in syngas quality and pipeline blockage.

[0009] 2. High moisture content in syngas

[0010] In existing top-suction gasifiers, the drying area and syngas outlet are relatively close. During the drying stage, almost all the moisture volatilized from the biomass enters the syngas without reacting with the carbon in the bed to form hydrogen and carbon monoxide, resulting in a high moisture content in the syngas.

[0011] 3. Some existing top-suction gasifiers ventilate from the side wall, resulting in uneven distribution of the gasifying agent inside the furnace and uneven burning inside the furnace.

[0012] 4. The existing ventilation method of the top suction gasifier is generally side wall or bottom ventilation. The lack of air distribution device will lead to uneven distribution of gasifying agent in the furnace. Because the gasifying agent concentration is high, it is very easy to react with carbon. The biomass in the reaction area will be consumed, resulting in a decrease in air pressure drop and concentrated flow of gasifying agent, causing uneven burning in the furnace. Summary of the Invention

[0013] To address the problems existing in the prior art, this invention proposes an improved updraft biomass gasification method and apparatus. By modifying the traditional updraft biomass gasifier, changing the bed shape, and altering the direction of steam and syngas flow, the steam undergoes a gasification reaction through the bed, resulting in a syngas outlet temperature higher than that of the traditional updraft fixed bed. A tar filter layer is also formed, filtering out tar and reducing its content in the syngas. This solves the problem of high tar content in traditional updraft gasifiers. Simultaneously, it effectively increases the proportion of hydrogen and carbon monoxide in the outlet syngas, improving syngas quality.

[0014] To achieve the above objectives, the present invention adopts the following technical solution:

[0015] An improved top-suction biomass gasification device includes an outer wall of the furnace body, a feed pipe, an inner baffle, a solid collection water tank, an air inlet pipe, and a grate.

[0016] The furnace body is vertical, with an installation hole at the top center and a synthetic combustible gas outlet at the top edge;

[0017] The feed pipe is inserted into the mounting hole, and the connection is sealed. The feed pipe section is located outside the outer wall of the furnace body and is used to feed biomass.

[0018] Solid collection water tanks are installed on the lower part of the outer wall of the furnace body and are interconnected. The solid collection water tanks are filled with water.

[0019] The air inlet pipe runs through the solid water collection tank, with one end connected to the grate and the other end connected to the external fan.

[0020] The grate is located between the solid collection tank and the outer wall of the furnace body, and the gap around the grate and the outer wall of the furnace body is the solid outlet.

[0021] The end of the feed pipe located inside the outer wall of the furnace body is inclined, and an inner baffle is provided around the inclined surface. The inner baffle has an arc structure and the inner ring of the inner baffle is connected to the feed pipe, while the outer ring is connected to the inner wall of the outer wall of the furnace body. The opening of the inner baffle is located on the lower side of the inclined surface of the feed pipe, forming the bed syngas outlet. The area around the feed pipe at the upper part of the inner baffle is the syngas flow channel.

[0022] As a further preferred option, the end of the feed pipe located outside the outer wall of the furnace body is equipped with a biomass buffer bin, and the biomass buffer bin is connected to a feed screw for feeding biomass.

[0023] As a further preferred option, an observation hole is also provided on the top of the outer wall of the furnace.

[0024] As a further preferred option, air distribution vents are distributed on the grate, and an air distributor is built into the grate.

[0025] As a further preferred option, a steam inlet is provided on the outer wall of the furnace near the grate.

[0026] As a further preferred option, the bottom inner wall of the furnace body is provided with a bed narrowing to reduce the space for direct biomass fall.

[0027] As a further preferred option, the outer wall of the furnace is cylindrical, and the gap width of the solid outlet is 1 / 15 to 1 / 10 of the diameter of the outer wall of the furnace.

[0028] Beneficial effects

[0029] I. Low moisture content in syngas

[0030] In this invention, all the water in the biomass enters the bed to participate in the gasification reaction, generating CO and H2. Compared with the traditional top-suction fixed-bed gasifier, it can effectively reduce the H2O content in the syngas and increase the CO and H2 content in the syngas.

[0031] II. Effective Reduction of Tar Content: Since the syngas outlet is located between the reduction and oxidation layers, the temperature is higher than that of traditional top-suction fixed-bed gasifiers. At this temperature, most of the tar is in the gas phase, and under high temperature, the tar further decomposes into smaller molecule gases. Simultaneously, the solid material at the outlet provides secondary filtration of the highly viscous tar, significantly reducing the tar content. The spiral annular flow channel increases the residence time of the syngas, which is beneficial for secondary reactions between gases.

[0032] Third, the air distribution is more uniform, and the introduction of steam makes the gasification reaction more complete.

[0033] A rotating grate connected to an air distributor is installed at the bottom of the furnace body. The air distributor is arranged in multiple layers, which can greatly enhance the uniformity of air distribution inside the bed. At the same time, steam injection holes are set around the bed. Injecting steam can further convert carbon into CO and H2, reduce the carbon content in the outlet solids, and increase the H2 and CO content in the synthesis gas. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the internal structure of the present invention;

[0035] Figure 2 This is a top view of the furnace baffle.

[0036] Figure 3 This is a schematic diagram of the bed layer position in the present invention;

[0037] In the diagram: 1. Air inlet, 2. Bed narrowing, 3. Steam inlet, 4. Furnace outer wall, 5. Furnace inner baffle, 6. Synthetic combustible gas outlet, 7. Biomass buffer bin, 8. Feed screw, 9. Observation hole, 10. Synthetic gas flow channel, 11. Bed syngas outlet, 12. Air distributor, 13. Air distributor, 14. Solid collection tank, 15. Solid outlet, 16. Grate, 17. Feed pipe. Detailed Implementation

[0038] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0039] This invention proposes an improved upward-suction gasifier, the main structure of which is as follows: Figure 1 As shown. The main components of the furnace body are the feeding screw, buffer hopper, feeding pipe, furnace body, exhaust screw channel, air distribution chamber, grate, and solid residue trough.

[0040] Feeding: Naturally dried biomass, such as formwork, straw, rice husks, and garden waste, is crushed to maintain a particle size of less than 5cm. The biomass pellets are then fed into a screw feeder, which conveys them to a biomass buffer silo. A discharge valve is installed at the bottom of the buffer silo, and the flow rate of biomass entering the furnace is controlled by adjusting the rotation speed (2-10t / h). After being added to the furnace, the biomass naturally sinks along the feed pipe under gravity.

[0041] Drying Zone: The feed pipe is made of steel, which has strong thermal conductivity. After exchanging heat with the high-temperature syngas outside, the heat is transferred into the feed pipe to dry the biomass. As the temperature of the biomass rises, at temperatures above 100°C, almost all the moisture inside evaporates, forming water vapor that moves downwards with the biomass in the feed pipe.

[0042] Cracking zone: As the biomass moves downward, its temperature rises rapidly due to the high temperature of the syngas and the radiation from the bottom bed. When it reaches the bottom of the feed pipe, the temperature approaches 500°C. At this point, volatiles are rapidly released from the biomass, mainly small molecules such as CO, CH4, CO2, and H2. The volatilized small molecules, along with the evaporated water, enter the gasification bed zone at the bottom of the feed pipe.

[0043] Reduction Zone (Gasification Zone): The left side of the feed pipe wall is higher than the right side. Therefore, after biomass is added to the furnace, the left side experiences less resistance, and most of the biomass accumulates on the left side of the furnace. The biomass gasification bed distribution inside the furnace exhibits a distribution characteristic of more on the left and less on the right, which differs from the distribution of all existing top-suction gasifiers. The left side has more biomass and is the main gasification reaction zone. After the biomass falls into the bed from the bottom of the feed pipe, the temperature inside the bed is around 700-900℃. After water vapor enters the bed, it reacts with the remaining carbon, and some of the moisture is converted into CO and H2, which can reduce the moisture content in the syngas. This characteristic is similar to that of down-suction gasifiers. In addition, after the gasifying agents such as air and water vapor undergo oxidation reactions in the oxidation zone, the remaining oxygen and water vapor will also enter the reduction zone and react with carbon to convert into CO and H2.

[0044] Oxidation Zone: The carbon remaining from the reduction zone continues to move downwards under gravity into the oxidation zone, which is the main site where carbon reacts with gasifying agents such as oxygen and water vapor. Air is introduced from the bottom ventilation duct using a booster fan. After passing through the grate air distributor, the air enters the bed oxidation zone, where it reacts with the carbon, releasing a large amount of heat to provide energy for the gasification reaction. The temperature in this bed is between 900-1200℃. The bottom grate air distributor rotates clockwise or counterclockwise, approximately every 1-5 minutes. During this rotation, the remaining solids slowly fall along the gaps in the grate and furnace wall. At this point, the temperature of the remaining solids is approximately 300-400℃. After falling, they enter a water tank for cooling. An air distributor is connected to the grate, allowing the air vaporizing agent to enter the bed through the distributor. The air inlet pressure is 3-5 kPa, the temperature is 25-80℃, and the ER (actual air volume / theoretical air volume) is 0.15-0.3. The ventilation holes are arranged in multiple layers (4-8 layers) to ensure more uniform gas distribution into the bed. Openings for water vapor are made on the furnace wall in the oxidation zone, with a diameter of 0.5-2 cm, an inlet pressure of 3-5 kPa, and a temperature of 105-150℃. By additionally introducing water vapor into the furnace, more carbon reacts with the water vapor, thereby reducing the carbon content in the solid residue and increasing the CO and H2 content in the combustible gas.

[0045] Gas outlet area:

[0046] The generated syngas exits the bed at the outlet on the right side of the furnace body. The outlet area is located between the gasification and oxidation zones, specifically in the syngas flow channel. Compared to traditional top-suction fixed-bed furnaces, the temperature here is still relatively high, approximately 300-500℃. All syngas must pass through this area. At this temperature, most of the tar is in a gaseous state, and this temperature promotes further secondary decomposition of large tar molecules in the syngas, reducing the tar content and improving syngas quality. Furthermore, solid residues accumulate at this location, forming a natural filter layer for uncracked, highly viscous tar, further reducing the tar content in the syngas and alleviating pipe blockage. The syngas leaving the bed flows upwards along a spiral annular flow channel. Compared to traditional top-suction gasifiers, this flow channel allows for a longer residence time and turbulent kinetic energy, resulting in more complete secondary reactions between the gas phases.

[0047] Furnace Description: The furnace body is divided into drying, pyrolysis, reduction, and oxidation zones from top to bottom, accommodating different types of biomass such as templates, straw, waste garden plants, rice husks, corn cobs, cotton stalks, and rice straw. Crushed biomass (particle size less than 5cm) is fed into a frequency-controlled conveyor screw, with the amount of biomass added to the hopper adjusted by frequency regulation. A biomass buffer silo with a capacity of 5-7 tons of biomass is connected below the conveyor screw. A frequency-controlled feed control valve is connected below the buffer silo, adjusting the frequency to control the quality of biomass entering the furnace. A feed pipe, made of carbon steel with a diameter D of 1-2.5m, extends within the furnace to the gasification zone and the furnace body's constriction point. The bottom of the feed pipe is on an inclined plane. The right side of the feed pipe extends 0.45-0.6 times the furnace height, and the angle between the straight line containing the lowest points on the left and right sides of the feed pipe and the horizontal line is 40-60 degrees. A flat baffle, 0.8-2 cm thick, is installed between the feed pipe and the furnace wall. An opening of 90-125 degrees is located on the right side of the baffle to allow syngas to flow out. One of the baffle's positioning points is the lowest point on the right side of the feed pipe, forming an angle of approximately 45-60 degrees with the horizontal. The furnace exterior is typically made of carbon steel with a diameter of 2.5-5.5 m. The interior is lined with refractory material, 0.05-0.1 times the furnace diameter, to prevent high-temperature damage to the furnace wall and to provide insulation. The furnace interior wall and the feed pipe form a spiral annular flow channel for syngas outflow, connecting to the gas outlet on the upper left side of the furnace. The gas outlet is square or circular, with a flow velocity of 2-20 m / s. The furnace height (excluding the lower water tank) is 4.5-9m. The lower bed section of the furnace body is fitted with a refractory-material constriction, the height of which is 0.25-0.35 times the furnace body height. The bottom of the constriction is flush with the bottom of the bed, and the middle part of the constriction is the thickest, with a thickness of 0.15-0.25 times the furnace body diameter. Steam injection holes are opened on the furnace wall around the lower bed section (0-0.2 times the furnace body height), distributed around the furnace body, with a number ranging from 10 to 40. The injected steam pressure is 3-5 kPa, the hole diameter is 0.5-2 cm, and the injected steam volume is 0-0.4 times the mass of the injected air. A rotating grate is installed at the bottom of the furnace body, rotating at 1-5 revolutions per minute. Residual solids slowly fall under the action of the rotating grate, falling into the water tank through the gap between the grate and the furnace shell. The grate is equipped with an air distributor with 12-30 ventilation holes to evenly distribute air into the furnace. The air pressure is 3-5 kPa, the temperature is 25-80℃, and the ER (actual air volume / theoretical air volume) is 0.15-0.3. The ventilation holes are arranged in multiple layers (4-8 layers) and can be adjusted vertically. A water tank with a volume of 3-20 m³ is located at the bottom of the furnace. 3 The high-temperature residual solids fall into a water tank for cooling. An observation hole is located at the top of the furnace body, allowing observation of the furnace's internal conditions after a sight glass is installed.

[0048] Example

[0049] (1) Feeding

[0050] In this embodiment, the furnace body is 6.5m high and 3.5m in outer diameter. The crushed biomass is fed into the buffer silo 7 via a screw conveyor 8. The screw conveyor is a variable frequency screw conveyor, allowing adjustment of the amount of material added to the buffer silo. The bottom of the buffer silo 7 is connected to a variable frequency feed valve. The biomass is fed into the feed pipe via the variable frequency feed valve. The feed pipe has a diameter of 1.2m and a length of 4m. The angle between the bottom plane of the feed pipe and the horizontal plane is 48 degrees. The baffle inside the furnace is coplanar with the bottom plane of the feed pipe, and the baffle thickness is 1.8cm.

[0051] (2) Gasifying agent

[0052] Air is introduced into the air distribution chamber 13 through an air duct by a booster fan. The air distribution chamber is connected to the grate 16 and has four layers of openings, allowing air to enter the furnace bed evenly. This multi-layer ventilation ensures a more uniform distribution of oxidant in the oxidation zone, preventing uneven temperature distribution within the oxidation bed. Twenty steam nozzles 3 are installed around the furnace body, delivering steam into the furnace at a pressure of 3 kPa.

[0053] (3) Gasification process

[0054] After entering the furnace, the biomass is distributed under the guidance of the feed pipe. During feeding, heat exchange occurs between the biomass and the feed pipe wall. When the biomass temperature exceeds 100℃, internal moisture rapidly precipitates out, accompanying the biomass as it continues to move downwards. Upon reaching the bottom of the feed pipe, the temperature is around 500℃. At this point, volatiles within the biomass rapidly precipitate out, forming small molecules of CH4, H2, CO, and CO2, while tar enters the reduction layer. Inside the reduction layer, the moisture precipitated from the biomass undergoes a reduction reaction with carbon. The temperature of this bed is 800-900℃, allowing the reduction reaction to proceed rapidly. Under this reaction, a large amount of the volatile moisture from the biomass is converted into H2 and CO, exiting the bed from the right-side outlet of the furnace. The remaining solids enter the oxidation zone and undergo an oxidation reaction with oxygen in the air. This oxidation reaction releases a large amount of heat, keeping the bed temperature below 1000-1200℃. Oxygen and carbon react in the oxidation layer to produce large amounts of CO and CO2. The generated high-temperature gas enters the reduction layer, where some of the CO2 reacts with carbon to produce CO. The syngas outlet is located on the right side of the furnace body, below the reduction layer but above the oxidation layer, with a temperature of 350℃. Tar and syngas produced by biomass pyrolysis must pass through this area. At this temperature, most of the tar is in a gaseous state, and large tar molecules undergo secondary pyrolysis, breaking down into smaller molecules. Furthermore, due to the action of solid residues, highly viscous tar is filtered into the bed, thus significantly reducing the tar content in the syngas. The syngas and tar leaving the bed are discharged through a spiral annular flow channel and gas outlet 6.

[0055] (4) Slag removal process

[0056] Solids leaving the oxidation zone are discharged through a rotating grate driven by a motor at a speed of 1 r / h. The solids leaving the oxidation zone have a temperature of 300-500℃ and enter a water tank 14 through outlet 15 for cooling.

[0057] The following are specific operational examples of the improved gasifier described above to illustrate the beneficial effects of the present invention.

[0058] Example 1 (This demonstrates that it can effectively reduce the moisture and tar content in syngas)

[0059] Table 1. Elemental and Industrial Analysis of Biomass Materials

[0060]

[0061] Operating conditions:

[0062] Biomass type: wood chips

[0063] Feed particle size: 2-5cm

[0064] Biomass feed rate: 7t / h

[0065] Furnace internal pressure: 0.5 kPa

[0066] vaporizing agent: air

[0067] Air equivalent ratio (ER): 0.25

[0068] Air intake volume: 8064m³ 3 / h

[0069] Using sawdust as the raw material for gasification, the gasification process was carried out under the above operating conditions, and the gasification results are as follows.

[0070] The composition of the syngas at the outlet is shown in Table 2:

[0071] Table 2 Composition of Syngas

[0072] Gas composition <![CDATA[CH4]]> <![CDATA[CO2]]> <![CDATA[H2]]> CO <![CDATA[H2O]]> <![CDATA[N2]]> other Volume fraction (%) 1.2 13 18 18 5 44 0.8

[0073] Gasification efficiency: 80%

[0074] Carbon content of ash: 4.1%

[0075] Combustible gas tar content: <5g / Nm 3

[0076] The results above show that the H2O volume fraction at the gasifier outlet in this embodiment is much lower than that of traditional updraft gasifiers (where the water vapor volume fraction at the gasification outlet is 8%-15%). This demonstrates the beneficial effect of this invention in reducing the moisture content in syngas. This effect is similar to that of downdraft gasifiers, but avoids the adverse effects of CO and H2 in the syngas being oxidized by oxygen. Furthermore, due to the reaction between moisture and carbon, the carbon content in the ash is reduced, falling below the 8%-15% level of traditional updraft gasifiers. The tar content is also significantly lower than that of traditional updraft gasifiers for similar biomass feedstocks, which typically have a tar content of 8-20 g / Nm3.

[0077] Example 2 (illustrates that different types of biomass have good adaptability)

[0078] Table 3. Elemental and Industrial Analysis of Biomass Materials

[0079]

[0080] Operating conditions:

[0081] Biomass types: sawdust, corn cobs, rice straw and stalks

[0082] Biomass feed rate: 7t / h

[0083] Feed particle size: 2-5cm

[0084] Furnace internal pressure: 0.5 kPa

[0085] Vaporizing agent: air plus steam

[0086] Air equivalent ratio (ER): 0.22

[0087] Steam mass to air mass ratio: 0.1

[0088] Using sawdust as the gasification raw material, the gasification process was carried out under the above operating conditions, and the gasification results are as follows:

[0089] The composition of syngas is shown in Table 4:

[0090] Table 4 Composition of Syngas

[0091] Gas composition <![CDATA[CH4]]> <![CDATA[CO2]]> <![CDATA[H2]]> CO <![CDATA[H2O]]> <![CDATA[N2]]> other Wood chips 1.3 10.8 21.3 18.4 6.2 41.2 0.8 corn cob 1.6 12.5 19.7 17.9 5.1 42.1 1.1 straw 1.23 13.5 20.2 16.9 5.9 41.9 0.37 cotton stalks 1.21 14.7 21.2 16.8 4.9 41 0.19

[0092] Gasification efficiency: Wood chips: 81%, Corn cobs: 78%, Rice straw: 75%, Cotton stalks: 82%

[0093] Carbon content of ash residue: sawdust 3.85%, corn cob 4.25%, rice straw 3.88%, cotton stalk 4.53%.

[0094] Combustible gas tar content: all less than 4.59 g / Nm³ 3

[0095] The results above show that the gasification effect analysis of this case using multiple types of biomass revealed that the tar content of all four biomass types was significantly lower than that of traditional updraft gasifiers, indicating that this type of gasifier can effectively reduce the tar content of different types of biomass. Furthermore, adding steam at 0.1 times the mass of air as a gasifying agent increased the concentration of H2 at the outlet, thereby enhancing the calorific value of the syngas.

[0096] (1) A variable frequency conveying screw is connected to a biomass buffer silo with a capacity of 5-7 tons of biomass. A variable frequency feeding control valve is connected to the buffer silo, and a feed pipe is connected to the control valve. The feed pipe is made of carbon steel with a diameter D of 1-2m. The feed pipe extends into the furnace to the gasification zone and to the position of the furnace body contraction. The bottom of the feed pipe is on the right side of the pipe, and the extension length on the right side is 0.45-0.6 times the height of the furnace body. The angle between the straight line containing the lowest part on the left and the lowest part on the right of the feed pipe and the horizontal line is 40-60 degrees.

[0097] (2) The area between the feed pipe and the furnace wall is equipped with an internal baffle, which is about 45-60 degrees with the horizontal direction and has a thickness of 0.8-2cm. The baffle has an opening on the right side for the synthesis gas to flow out, and the opening angle is 90-125 degrees.

[0098] (3) The outer wall of the furnace body is generally made of carbon steel with a diameter of 2.5-5.5m. The inner side of the furnace body is filled with refractory material with a thickness of 0.05-0.1 times the diameter of the furnace body.

[0099] (4) The inner wall of the furnace body and the feed pipe form a spiral annular flow channel for syngas outflow. The flow channel is connected to the gas outlet on the upper left side of the furnace body. The gas outlet is square or circular.

[0100] (5) The furnace body height (excluding the lower water tank) is 4.5-9m. The lower bed of the furnace body is equipped with a refractory material constriction, the height of which is 0.25-0.35 times the height of the furnace body. The bottom of the constriction is flush with the bottom of the bed. The middle part of the constriction is the thickest, and its thickness is 0.15-0.25 times the diameter of the furnace body.

[0101] (6) Steam injection holes are opened on the furnace wall around the lower bed layer (0-0.2 furnace height). The number of injection holes can be between 10 and 40. The injection steam pressure can be 3-5 kPa, the injection hole diameter is 0.5-2 cm, and the injection steam volume is 0-0.4 times the mass of the injected air.

[0102] (7) A rotating grate is installed at the bottom of the furnace body, with a rotation speed of 0.5-3 revolutions per hour. An air distributor is installed in the grate, with 12-30 ventilation holes to evenly deliver air into the furnace. The pressure of the delivered air is 1.5-2 MPa, the temperature is 25-80℃, and the ER (actual air volume / theoretical air volume) is 0.15-0.4. The ventilation holes are arranged in multiple layers (4-8 layers) and can be adjusted up and down.

[0103] (8) A water tank with a volume of 3-20m³ is provided at the bottom of the furnace. 3 ;

[0104] (9) The gas outlet channel is a spiral annular channel, which is connected to the gas outlet on the left side above the furnace body.

[0105] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An improved upward-suction biomass gasification device, characterized in that: Includes the outer wall of the furnace body (4), the feed pipe (17), the inner baffle (5), the solid collection water tank (14), the air inlet pipe (1), and the grate (16); The outer wall (4) of the furnace body is vertical, with an installation hole at the top center and a synthetic combustible gas outlet (6) at the top edge. The feed pipe (17) is inserted into the mounting hole, and the connection is sealed. Part of the feed pipe (17) is located outside the outer wall (4) of the furnace body and is used to feed biomass. The solid water collection tank (14) is installed on the lower part of the outer wall (4) of the furnace body and is connected to each other. The solid water collection tank (14) is filled with water. The air inlet pipe (1) is installed through the solid collection water tank (14), with one end connected to the grate (16) and the other end connected to the external fan; The grate (16) is located between the solid collection tank (14) and the outer wall of the furnace (4), and the gap around the grate (16) and the outer wall of the furnace (4) is the solid outlet (15). The end of the feed pipe (17) located inside the outer wall (4) of the furnace body is inclined, and an inner baffle (5) is provided around the inclined surface. The inner baffle (5) is an arc structure. The inner baffle (5) is arranged along the plane of the inclined surface. The inner ring of the inner baffle (5) is connected to the feed pipe (17), and the outer ring is connected to the inner wall of the outer wall (4) of the furnace body. The opening of the inner baffle (5) is located on the lower side of the inclined surface of the feed pipe (17), forming a bed synthesis gas outlet (11). The area around the feed pipe (17) above the inner baffle (5) is a synthesis gas flow channel (10). The grate (16) is provided with air distribution vents (12) and an air distributor (13) is built into the grate (16). A steam inlet (3) is provided on the outer wall of the furnace body (4) near the grate (16); The bottom inner wall of the furnace body (4) is provided with a bed narrowing (2) to reduce the space for direct fall of biomass.

2. An improved upward-suction biomass gasification device according to claim 1, characterized in that: The feed pipe (17) is provided with a biomass buffer chamber (7) at the end outside the outer wall (4) of the furnace body, and a feed screw (8) for feeding biomass is connected to the outside of the biomass buffer chamber (7).

3. An improved upward-suction biomass gasification device according to claim 1, characterized in that: The top of the outer wall (4) of the furnace body is also provided with an observation hole (9).

4. An improved upward-suction biomass gasification device according to claim 1, characterized in that: The outer wall of the furnace body (4) is a cylindrical structure, and the gap width of the solid outlet (15) is 1 / 15 to 1 / 10 of the diameter of the outer wall of the furnace body (4).

Images