CN115851319A - Improved updraft biomass gasification device - Google Patents
Improved updraft biomass gasification device Download PDFInfo
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Abstract
The invention relates to an improved updraft biomass gasification device, which comprises a furnace body outer wall, a feeding pipe, a baffle plate in a furnace, a solid collecting water tank, an air inlet pipe and a fire grate; the center of the top of the outer wall of the furnace body is provided with a mounting hole, and the top is provided with a synthetic combustible gas outlet; the feeding pipe is inserted into the mounting hole; the solid water collecting tank is arranged at the lower part of the outer wall of the furnace body; the air inlet pipe penetrates through the solid collecting water tank, one end of the air inlet pipe is provided with a fire grate, and the other end of the air inlet pipe is communicated with the outside; the end part of the feeding pipe, which is positioned in the outer wall of the furnace body, is an inclined plane, the periphery of the inclined plane is provided with a furnace inner baffle, the furnace inner baffle is of a major arc structure and is arranged along the plane of the inclined plane to form a bed layer synthetic gas outlet. The invention improves the traditional updraft biomass gasifier, solves the problem of high tar content of the traditional updraft gasifier, and can effectively improve the ratio of hydrogen to carbon monoxide in the outlet synthesis gas and improve the quality of the synthesis gas.
Description
Technical Field
The invention relates to the technical field of environment-friendly furnace equipment, in particular to an improved updraft type fixed bed biomass gasification device.
Background
With the utilization of high-carbon fossil energy, the problem of increasingly serious climate change is receiving wide attention, and zero-carbon renewable energy represented by biomass energy is the development direction of future energy. Compared with other renewable energy sources, the biomass energy can provide various industrial products such as high-value fuel gas, biodiesel, high-quality chemicals, high-grade steam, biochar fertilizer raw materials and the like besides power, is served for various fields such as civil life, traffic, agriculture, industry, building heating and the like, and occupies an important position in the future energy utilization field of China. The biomass energy utilization technology mainly comprises two main types of thermochemical conversion and biochemical conversion, wherein the thermochemical method has higher efficiency, and biomass gasification is one of the most main thermochemical disposal methods.
An updraft biomass fixed bed gasification furnace is biomass gasification reaction equipment commonly used in industry, materials of the updraft gasification furnace move downwards, gas moves upwards, and the materials sequentially pass through drying, cracking, reducing and oxidizing stages. The high-temperature gas and the materials are in counter flow, and after the materials are heated, dried and cracked by the high-temperature gas, the heterogeneous combustion reaction of residual solids and oxygen mainly occurs at the bottom of the furnace body. The updraft type furnace has high heat efficiency, relatively loose requirements on raw materials and high hydrogen content in the synthesis gas, but has the defect of high tar content in the synthesis gas. This patent improves traditional updraft type gasifier to solve the shortcoming that tar content is high in the synthetic gas, improve the synthetic gas quality simultaneously.
The application number is 202011333813.4, the name is "an updraft type fixed bed biomass gasification furnace", and this patent proposes an updraft type fixed bed biomass gasification furnace, and this patent gasification furnace mainly includes bucket elevator, feed arrangement, gasifier main furnace, grate, tar recovery unit etc.. The patent improves feeding equipment, reduces the blocking phenomenon in the feeding process, but the main furnace body structure of the gasification furnace is the same as that of the traditional updraught type gasification furnace, and the problem of high tar content is still not solved;
application number 201420483698.2, the name is "the updraft type biomass gasification stove of giving vent to anger in middle part", this patent proposes the fixed bed updraft type gasification stove of giving vent to anger in middle part to improve the gas quality of output combustible gas. Biomass is followed the top pan feeding in this patent, and the bottom air inlet is with arranging the sediment, but the gasifying agent dwell time is shorter in this patent device, probably leads to gasification reaction insufficient, and the synthetic gas quality is lower, and the tar problem also does not well solve simultaneously.
Therefore, the biomass of the traditional updraft gasifier is added from the top of the furnace, the biomass sequentially undergoes the processes of drying, cracking, reduction, oxidation and the like, the high-temperature gas and the material flow in a countercurrent manner, and the material is heated, dried and cracked by the high-temperature gas. Out-of-phase combustion reaction of residual solid carbon and oxygen mainly occurs at the bottom of the furnace body. According to the experience and theoretical analysis of the operation case, the concrete disadvantages are as follows:
1. high tar content in synthesis gas
In the existing updraft fixed bed gasification furnace, tar generated in the pyrolysis stage does not flow out from an outlet through pyrolysis, so that the tar content in the synthetic gas is high, the quality of combustible gas is influenced, and the quality of the synthetic gas is further reduced and a pipeline is blocked.
2. High water content of synthesis gas
The existing updraft gasifier is close to the outlet of the synthesis gas in the drying area, almost all the water volatilized by the biomass enters the synthesis gas in the drying stage, the water is not gasified with the carbon in the bed layer and is converted into hydrogen and carbon monoxide, and the water content in the synthesis gas is high.
3. The existing part of the upper suction type gasification furnace is ventilated from the side wall surface, so that the gasification agent in the furnace is not uniformly distributed, and the phenomenon of partial combustion occurs in the furnace.
4. The existing updraft type gasification furnace is generally ventilated at the side wall surface or the bottom, and the lack of an air distribution device can cause uneven distribution of a gasification agent in the furnace, and because a part with higher concentration of the gasification agent is very easy to react with carbon, biomass in a reaction area can be consumed, so that the pressure drop of air flow is reduced, the gasification agent flows in a concentrated manner, and the phenomenon of partial combustion in the furnace is caused;
disclosure of Invention
The invention provides an improved updraft biomass gasification method and a device thereof for solving the problems in the prior art, wherein a traditional updraft biomass gasification furnace is improved, the shape of a bed layer is changed, the flow direction of water vapor and synthetic gas is changed, the water vapor is subjected to gasification reaction through the bed layer, the outlet temperature of the synthetic gas is higher than that of the traditional updraft fixed bed, a tar filtering layer is formed, tar is filtered, the tar content in the synthetic gas is reduced, the problem of high tar content of the traditional updraft gasification furnace is solved, the proportion of hydrogen and carbon monoxide in the outlet synthetic gas can be effectively increased, and the quality of the synthetic gas is improved.
In order to achieve the purpose, the invention adopts the following technical scheme:
an improved updraft biomass gasification device comprises a furnace body outer wall, a feed pipe, a baffle plate in a furnace, a solid collecting water tank, an air inlet pipe and a furnace grate;
the outer wall of the furnace body is vertical, the center of the top is provided with a mounting hole, and the edge of the top is provided with a synthetic combustible gas outlet;
the feeding pipe is inserted into the mounting hole, the joint is sealed, and part of the feeding pipe is positioned outside the outer wall of the furnace body and used for throwing biomass;
the solid collecting water tank is arranged at the lower part of the outer wall of the furnace body and is communicated with the furnace body, and water is contained in the solid collecting water tank;
the air inlet pipe penetrates through the solid collecting water tank, one end of the air inlet pipe is connected with the fire grate, and the other end of the air inlet pipe is communicated with an external fan;
the fire grate is positioned between the solid collecting water tank and the outer wall of the furnace body, and a circle of gap between the fire grate and the outer wall of the furnace body is a solid outlet;
the end part of the feeding pipe, which is positioned in the outer wall of the furnace body, is an inclined plane, the periphery of the inclined plane is provided with a furnace inner baffle, the furnace inner baffle is of a U-arc structure, the plane of the inclined plane of the furnace inner baffle is arranged, the inner ring of the furnace inner baffle is connected with the feeding pipe, the outer ring of the furnace inner baffle is connected with the inner wall of the outer wall of the furnace body, the opening of the furnace inner baffle is positioned on the lower side of the inclined plane of the feeding pipe to form a bed layer synthetic gas outlet, and the peripheral area of the feeding pipe on the upper part of the furnace inner baffle is a synthetic gas flow channel.
As a further preferred scheme, a biomass buffer bin is arranged at the end part of the feeding pipe, which is positioned outside the outer wall of the furnace body, and a feeding screw for feeding biomass is connected outside the biomass buffer bin.
As a further preferable scheme, the top of the outer wall of the furnace body is also provided with an observation hole.
As a further preferable scheme, air distributing openings are distributed on the grate, and an air distributing device is arranged in the grate.
As a further preferable scheme, a water vapor inlet is arranged at the position of the outer wall of the furnace body close to the grate.
As a further preferable scheme, a bed layer necking for reducing the space for directly dropping the biomass is arranged on the inner wall of the bottom of the outer wall of the furnace body in the circumferential direction.
As a further preferable scheme, the outer wall of the furnace body is of a cylindrical structure, and the gap width of the solid outlet is 1/15-1/10 of the diameter of the outer wall of the furnace body.
Advantageous effects
1. The synthesis gas has low moisture content
In the invention, all moisture in the biomass enters the bed layer to participate in gasification reaction to generate CO and H2, and compared with the traditional updraught fixed bed gasifier, the content of H2O in the synthesis gas can be effectively reduced, and the content of CO and H2 in the synthesis gas can be increased.
2. The tar content is effectively reduced because the synthesis gas outlet is positioned between the reduction layer and the oxidation layer, the temperature is higher than that of the traditional updraught fixed bed gasification furnace, most of tar is in a gas phase at the temperature, tar can be further decomposed into micromolecular gas under the action of high temperature, and meanwhile, the solid substance at the outlet performs secondary filtration on tar with higher viscosity, so that the tar content is greatly reduced. The spiral annular flow channel increases the retention time of the synthesis gas, and is beneficial to the secondary reaction among gases.
3. The air distribution is more uniform, and the gasification reaction is more sufficient by introducing steam
The bottom of the furnace body is provided with a rotary grate connected with an air distributor, and the air distributor is arranged in multiple layers, so that the air distribution uniformity inside a bed layer can be greatly enhanced. Meanwhile, steam jet holes are arranged around the bed layer, and the carbon can be further converted into CO and H2 by injecting steam, so that the carbon content in the solid at the outlet is reduced, and the contents of H2 and CO in the synthesis gas are increased.
Drawings
FIG. 1 is a schematic view of the internal structure of the present invention;
FIG. 2 is a top view of a baffle plate in the furnace;
FIG. 3 is a schematic of the bed position of the present invention;
in the figure: 1. the biomass gasification furnace comprises an air inlet, 2 bed layer necking, 3 steam inlet, 4 furnace body outer wall, 5 furnace inner baffle, 6 synthetic combustible gas outlet, 7 biomass buffer bin, 8 feeding screw, 9 observation hole, 10 synthetic gas flow channel, 11 bed layer synthetic gas outlet, 12 air distribution port, 13 air distributor, 14 solid collecting water tank, 15 solid outlet, 16 grate and 17 feeding pipe.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.
The invention provides an improved updraft gasifier, the main structure of which is shown in figure 1. The main components of the furnace body are a feeding screw, a buffer storage bin, a feeding pipe, a furnace body, an air outlet screw flow passage, an air distribution bin, a grate and a solid residue outlet water tank.
Feeding: after naturally dried biomass such as templates, straws, rice hulls, garden waste and the like are crushed, particle size of particles is kept within 5cm, biomass particles are added into a spiral feeder, and the biomass particles are conveyed into a biomass buffer bin through a spiral. The bottom of the biomass buffer bin is provided with a discharge valve, and the flow (2-10 t/h) of the biomass entering the furnace is controlled by adjusting the rotating speed. After biomass is added into the furnace, the biomass naturally sinks along the feeding pipe under the action of gravity.
A drying area: the material of the feeding pipe is made of steel, has stronger heat conduction performance, and transfers heat into the feeding pipe to dry the biomass after exchanging heat with outside high-temperature synthesis gas. With the rise of the temperature of the biomass, the moisture in the biomass is almost completely volatilized at the temperature of more than 100 ℃, and water vapor is formed to move downwards along with the biomass in the feeding pipe.
Lysis zone: along with the downward movement of the biomass, the temperature of the biomass is rapidly increased due to the high-temperature action of the synthesis gas and the radiation action of the bottom bed layer, the temperature is close to 500 ℃ when the biomass reaches the bottom of the feeding pipe, and at the moment, volatile components in the biomass are rapidly separated out and mainly comprise micromolecular CO and CH 4 、CO 2 And H 2 And the volatilized small molecules enter the gasification bed area at the bottom of the feed pipe along with the evaporated water.
Reduction zone (gasification zone): the left side of the wall surface of the feeding pipe is higher, the right side of the wall surface of the feeding pipe is lower, so that the left side of the wall surface of the feeding pipe is less obstructed after biomass is added into the furnace, most of the biomass can be gathered at the left side of the furnace body, the distribution of the biomass gasification bed layer in the furnace has the distribution characteristic of more biomass at the left side and less biomass at the right side, and the distribution characteristic of the bed layer is different from the distribution of all the existing updraft beds. The left side has more biomass and is the main gasification reaction zone. The biomass falls from the bottom of the feeding pipe into the bed layer, the temperature in the bed layer is about 700-900 ℃, and after the steam enters the bed layer, the biomass and the residual carbonGasification reaction occurs, and the water is partially converted into C0 and H 2 The water content in the synthetic gas can be reduced, and the characteristic is similar to that of a downdraft gasification furnace. In addition, after the introduced gasifying agent such as air, water vapor and the like is subjected to oxidation reaction in the oxidation zone, the residual oxygen and water vapor also enter the reduction zone to be subjected to gasification reaction with carbon and converted into CO and H 2 。
An oxidation area: the remaining carbon from the reduction zone reaction continues to move downward under the force of gravity into the oxidation zone, which is the primary site for the carbon to react with gasifying agents such as oxygen and water vapor. Air is introduced from a bottom ventilation pipeline by using a booster fan, enters a bed oxidation zone after passing through a grate air distributor, and is subjected to oxidation reaction with carbon to release a large amount of heat so as to provide an energy source for gasification reaction, and the temperature in the bed is 900-1200 ℃. The grate air distributor at the bottom rotates clockwise or anticlockwise for about 1-5min every time, the reaction residual solid slowly falls down along the gap between the grate and the wall surface of the furnace body while rotating, the temperature of the residual solid at the moment is about 300-400 ℃, and the residual solid enters a water tank for cooling after falling down. The grate is connected with a wind distributor, air gasifying agent can enter the bed layer through the distributor, the air is introduced under the pressure of 3-5kPa, the temperature of 25-80 ℃, ER (actual air quantity/theoretical air quantity) is 0.15-0.3, and the ventilation holes are arranged in multiple layers (4-8 layers), so that the gas entering the bed layer is more uniform. The wall surface of the furnace body in the oxidation area is provided with an opening for introducing water vapor, the aperture is 0.5-2cm, the introduction pressure is 3-5kPa, and the temperature is 105-150 ℃. By additionally introducing steam into the furnace, more carbon and steam are subjected to gasification reaction, so that the carbon content in the solid residue is reduced, and the CO and H in the combustible gas are improved 2 The content of (a).
Gas outlet region:
the generated synthetic gas leaves the bed layer at the right outlet of the furnace body, the outlet area is positioned in the middle of the gasification area and the oxidation area, namely the position of the synthetic gas runner, compared with the traditional updraft type fixed bed, the temperature at the position is still higher, about 300-500 ℃, all the synthetic gas needs to pass through the area, most tar is in a gas phase state at the temperature, and the temperature can promote tar macromolecules in the synthetic gas to be further subjected to secondary decomposition, reduce the content of tar in the synthetic gas and improve the quality of the synthetic gas. In addition, solid residues are collected at the position, a natural filtering layer is formed on uncracked tar with high viscosity, the content of tar in the synthetic gas is further reduced, and the phenomenon of pipeline blockage is relieved. The synthesis gas leaving the bed layer flows upwards along the spiral annular flow channel, and compared with the traditional updraught gasification furnace, the flow channel enables the synthesis gas to have longer residence time and turbulent kinetic energy, so that the secondary reaction between gas phases is more sufficient.
Description of the furnace body: the furnace body can be divided into a drying area, a cracking area, a reduction area and an oxidation area from top to bottom, and is suitable for biomass of different types such as templates, straws, green plants in abandoned gardens, rice husks, corncobs, cotton stalks, straws and the like. Adding the crushed biomass (the particle size is less than 5 cm) into a conveying screw, wherein the conveying screw is of a variable frequency type, and controlling the amount of the biomass added into the bin by frequency regulation. The conveying screw is connected with a biomass buffer bin in a downward connection mode, and the capacity of the buffer bin is 5-7 tons of biomass capacity. The buffer bin is connected with a variable frequency feeding control valve in a downward connection mode, and the biological quality entering the furnace is controlled by adjusting the frequency. The control valve is connected with a feeding pipe in a downward connecting mode, the feeding pipe is made of carbon steel, the diameter D of the feeding pipe is 1-2.5m, the feeding pipe extends to a gasification area in the furnace to the position of a furnace body necking, and the plane where the bottom of the feeding pipe is located is an inclined plane. The length of the right side of the feeding pipe is 0.45-0.6 times of the height of the furnace body, and the included angle between the straight line of the lowest part at the left side and the lowest part at the right side of the feeding pipe and the horizontal line is 40-60 degrees. The area between the feeding material and the wall surface of the furnace body is provided with a plane baffle plate, the thickness of the plane baffle plate is 0.8-2cm, the right side of the baffle plate is provided with a hole for the synthetic gas to flow out, and the hole opening angle is 90-125 degrees. One positioning point of the baffle is the lowest point of the right side of the feeding pipeline, and the included angle between the baffle and the horizontal direction is about 45-60 degrees. The outer wall surface of the furnace body is generally made of carbon steel, the diameter of the outer wall surface is 2.5-5.5m, the inner side of the furnace body is provided with a refractory material, the thickness of the refractory material is 0.05-0.1 time of the diameter of the furnace body, the furnace wall can be prevented from being damaged by high temperature, and the furnace body is insulated. The inner wall surface of the furnace body and the feeding pipe form a synthesis gas outflow spiral annular flow channel, the flow channel is connected with a gas outlet at the upper part of the left side of the furnace body, the gas outlet is square or circular, and the flow velocity of outlet gas is 2-20m/s. Furnace body heightThe degree (without lower water tank) is 4.5-9m, the bed layer position at the lower part of the furnace body is provided with a necking made of refractory material, the height of the necking is 0.25-0.35 times of the furnace body, the bottommost position of the necking is flush with the bottommost position of the bed layer, the middle part of the necking is thickest, and the thickness of the necking is 0.15-0.25 times of the diameter of the furnace body. Steam jet holes are arranged on the wall surface of the furnace body around the bed layer part (0-0.2 of the height of the furnace body) at the lower part of the furnace body, and the number of the jet holes is 10-40. The steam pressure of the injected steam can be 3-5kPa, the diameter of the injection hole is 0.5-2cm, and the amount of the injected steam is 0-0.4 times of the mass of the injected air. The bottom of the furnace body is provided with a rotary grate, and the rotating speed is 1-5min per revolution. The remaining solids fall slowly under the action of the rotating grate and fall into the water trough from the gap between the grate and the furnace shell. The grate is provided with an air distributor, the grate is provided with 12-30 vent holes, air can be uniformly fed into the furnace, the pressure of the fed air is 3-5kPa, the temperature is 25-80 ℃, ER (actual air quantity/theoretical air quantity) is 0.15-0.3, and the vent holes are arranged in multiple layers (4-8 layers) and can be adjusted up and down. A water tank with a volume of 3-20m is arranged at the lowest part in the furnace 3 And the high-temperature residual solid falls into a water tank for cooling. The upper part of the furnace body is provided with an observation hole, and the working condition in the furnace can be observed after the sight glass is installed.
Examples
(1) Feeding in
In this example, the height of the furnace body was 6.5m, and the outer diameter of the furnace body was 3.5m. The broken biomass is added into a buffer bin 7 through a screw conveyer 8, the screw conveyer is a variable frequency screw, and the material amount added into the buffer bin can be adjusted. The bottom of the buffer bin 7 is connected with a variable-frequency feeding valve. The biomass is fed into the feeding pipe through the variable-frequency feeding valve, the diameter of the feeding pipe is 1.2m, the length of the feeding pipe is 4m, the included angle between the plane of the bottom of the feeding pipe and the horizontal plane is 48 degrees, the plane of the bottom of the feeding pipe and the plane of the bottom of the feeding pipe are coplanar, and the thickness of the baffle is 1.8cm.
(2) Gasifying agent
Air is let in air distribution chamber 13 from air conduit by booster fan, and air distribution chamber links to each other with grate 16, and air distribution chamber has 4 layers of trompils for the even bed in the stove that gets into of air, and multilayer ventilates and makes in the stove oxidation zone oxidant distribute comparatively evenly, avoids the inside inhomogeneous phenomenon of temperature that appears of oxidation bed. The number of the steam nozzles 3 is 20, and the steam is fed into the furnace under the pressure of 3 kPa.
(3) Gasification process
After the biomass enters the furnace, the material distribution process is completed under the guiding action of the feeding pipe. In the biomass feeding process, heat exchange is carried out between the biomass and the wall surface of the feeding pipe, and when the temperature of the biomass is higher than 100 ℃, the internal moisture is quickly separated out and moves downwards along with the biomass. When the biomass moves to the bottom of the feeding pipe, the temperature is about 500 ℃, and at the moment, volatile matters in the biomass are quickly separated out to form micromolecule CH 4 、H 2 CO and CO 2 And the tar enters the reduction layer. Inside the reduction layer, the water separated out from the biomass and carbon are subjected to reduction reaction, the temperature of the bed layer is 800-900 ℃, the reduction reaction can be rapidly carried out, and under the reaction, a large amount of water volatilized from the biomass is converted into H 2 And CO, and the CO leaves the bed layer from the outlet at the right side of the furnace body. The rest solid enters an oxidation zone to generate oxidation reaction with oxygen in the air, and the oxidation reaction releases a large amount of heat, so that the temperature of the bed layer is within 1000-1200 ℃. The oxygen and carbon react in the oxide layer to generate CO and CO in large quantity 2 The generated high-temperature gas enters the reduction layer, and part of CO enters the reduction layer 2 Reacts with carbon to form CO. The outlet of the synthesis gas is located at the right side of the furnace body, which is lower than the reduction layer but higher than the oxidation layer, and the temperature of the synthesis gas is 350 ℃. The tar and the synthesis gas generated by biomass cracking need to pass through the region, most of the tar is in a gas phase state at the temperature, and the macromolecular tar can still be subjected to secondary cracking to be cracked into small molecules. In addition, under the action of the solid residue, the tar with larger viscosity can be filtered in the bed layer, so that the tar content in the synthesis gas can be greatly reduced. The synthesis gas and tar leaving the bed layer are discharged through the gas discharge port 6 through the spiral annular flow passage.
(4) Slag discharge process
The solid leaving the oxidation area is discharged through a rotary grate which is driven by a motor to rotate at the rotating speed of 1r/h. The solids leaving the oxidation zone have a temperature of 300-500 c and enter the water tank 14 via outlet 15 for cooling.
The following is a specific operation example of the improved gasification furnace to illustrate the beneficial effects of the present invention.
Example 1 (demonstrating effective reduction of moisture and tar levels in syngas)
TABLE 1 elemental and Industrial analysis of Biomass Material
The operating conditions are as follows:
the biomass species: wood chip
Feeding particle size: 2-5cm
Feeding amount of biomass: 7t/h
Pressure in the furnace: 0.5kPa
Gasifying agent: air (a)
Air equivalence ratio ER:0.25
Air intake amount: 8064m 3 /h
The wood chips were used as a gasification raw material, and the gasification process was performed under the above-described operating conditions, and the gasification results were as follows.
The outlet syngas composition is shown in table 2:
TABLE 2 Synthesis gas composition
| Gas composition | CH 4 | CO 2 | H 2 | CO | H 2 O | N 2 | Others |
| Volume fraction (%) | 1.2 | 13 | 18 | 18 | 5 | 44 | 0.8 |
Gasification efficiency: 80 percent
Carbon content of ash: 4.1 percent
Combustible gas tar content: < 5g/Nm 3
From the above results, it can be seen that the outlet H of the gasification furnace in this embodiment 2 The volume fraction of O is far less than that of the traditional updraft gasifier (the volume fraction of water vapor at the gasification outlet is 8-15%), which can show the beneficial effect of the invention in reducing the water content in the synthesis gas, the effect is similar to that of the downdraft gasifier, but the CO and H in the synthesis gas are avoided 2 Etc. are oxidized by oxygen. In addition, the carbon content in the ash is reduced by the reaction of the moisture and the carbon, and is lower than the 8-15% level of the traditional updraft gasifier. The tar content is far lower than that of the traditional updraft gasifier for gasification of the same type of biomass raw materials, and the tar content is generally 8-20g/Nm & lt 3 & gt.
Example 2 (illustrating the better suitability of different types of biomass)
TABLE 3 Biomass Material elements and Industrial analysis
The operating conditions are as follows:
the biomass species: wood chip, corncob, rice straw and stalk
Feeding amount of biomass: 7t/h
Feeding particle size: 2-5cm
Pressure in the furnace: 0.5kPa
Gasifying agent: air plus steam
Air equivalence ratio ER:0.22
Steam mass to air mass ratio: 0.1
The wood chips were used as gasification raw material, and the gasification process was carried out according to the above-mentioned operating conditions, and the gasification results were as follows:
the syngas composition is shown in table 4:
TABLE 4 syngas composition
| Gas composition | CH 4 | CO 2 | H 2 | CO | H 2 O | N 2 | Others |
| Wood chip | 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 stalk | 1.21 | 14.7 | 21.2 | 16.8 | 4.9 | 41 | 0.19 |
Gasification efficiency: wood chip: 81 percent, corncob 78 percent, straw 75 percent and cotton stalk 82 percent
Carbon content of ash: 3.85% of wood chips, 4.25% of corncobs, 3.88% of straws and 4.53% of cotton stalks
Combustible gas tar content: are all less than 4.59g/Nm 3
From the above results, it can be seen that in this case, the gasification effect analysis is performed by using various biomass species, and the tar content of the four biomass species is much smaller than that of the conventional updraft gasifier, which indicates that the gasifier type can achieve the beneficial effect of reducing tar content for different biomass species. Meanwhile, steam with the mass of 0.1 time of that of the air is added as a gasifying agent, so that the outlet H is improved 2 The heat value of the synthesis gas can be improved.
(1) The variable-frequency conveying screw is connected with a biomass buffer bin in a downward connection mode, and the capacity of the buffer bin is 5-7 tons of biomass capacity. The buffer bin is connected with a variable-frequency feeding control valve, the control valve is connected with a feeding pipe, the feeding pipe is made of carbon steel, the diameter D is 1-2m, the feeding pipe extends to a gasification region in the furnace to the position of a furnace body necking, the bottommost part of the feeding pipe is the right side of the pipeline, the length of the right side extending into the gasification region is 0.45-0.6 times of the height of the furnace body, and the included angle between the straight line of the lowest part on the left side of the feeding pipe and the lowest part on the right side and the horizontal line is 40-60 degrees;
(2) The area between the feeding pipe and the wall surface of the furnace body is provided with a baffle plate in the furnace, the included angle between the baffle plate and the horizontal direction is about 45-60 degrees, the thickness is 0.8-2cm, the right side of the baffle plate is provided with a hole for the synthetic gas to flow out, and the hole opening angle is 90-125 degrees.
(3) The outer wall surface of the furnace body is generally made of carbon steel, the diameter of the outer wall surface is 2.5-5.5m, the inner side of the furnace body is provided with refractory materials, and the thickness of the refractory materials is 0.05-0.1 time of the diameter of the furnace body;
(4) The inner wall surface of the furnace body and the feeding pipe form a synthesis gas outflow spiral annular flow channel, the flow channel is connected with a gas outlet above the left side of the furnace body, and the gas outlet is square or round;
(5) The height of the furnace body (without a lower water tank) is 4.5-9m, a throat made of refractory material is arranged at the bed layer position at the lower part of the furnace body, the height of the throat part is 0.25-0.35 times of the furnace body, and the bottommost position of the throat is flush with the bottommost position of the bed layer. The middle part of the reducing mouth is thickest, and the thickness of the reducing mouth is 0.15 to 0.25 times of the diameter of the furnace body;
(6) Steam jet holes are arranged on the wall surface of the furnace body around the bed layer part (0-0.2 of the height of the furnace body) at the lower part of the furnace body, and the number of the jet holes is 10-40. The steam pressure sprayed in can be 3-5kpa, the diameter of the spray hole is 0.5-2cm, and the quantity of the sprayed steam is 0-0.4 times of the mass of the sprayed air.
(7) The bottom of the furnace body is provided with a rotary grate, and the rotating speed is 0.5-3h per revolution. An air distributor is arranged in the fire grate, 12-30 vent holes are arranged on the fire grate, air can be uniformly fed into the furnace, the pressure of the fed air is 1.5-2Mpa, the temperature is 25-80 ℃, ER (actual air quantity/theoretical air quantity) is 0.15-0.4, and the vent holes are arranged in a plurality of layers (4-8 layers) and can be adjusted up and down;
(8) A water tank with a volume of 3-20m is arranged at the lowest part in the furnace 3 ；
(9) The gas outlet flow passage is a spiral annular flow passage and is connected to a gas outlet on the left side above the furnace body.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.
Claims (7)
1. An improved updraft biomass gasification device is characterized in that: comprises a furnace body outer wall (4), a feeding pipe (17), a furnace inner baffle plate (5), a solid collecting water tank (14), an air inlet pipe (1) and a fire grate (16);
the outer wall (4) of the furnace body is vertical, a mounting hole is formed in the center of the top of the furnace body, and a synthetic combustible gas outlet (6) is formed in the edge of the top of the furnace body;
the feeding pipe (17) is inserted into the mounting hole, the joint is sealed, and the feeding pipe (17) is partially positioned outside the outer wall (4) of the furnace body and used for throwing biomass;
the solid collecting water tank (14) is arranged at the lower part of the outer wall (4) of the furnace body and is communicated with each other, and water is contained in the solid collecting water tank (14);
the gas inlet pipe (1) penetrates through the solid collecting water tank (14), one end of the gas inlet pipe is connected with the fire grate (16), and the other end of the gas inlet pipe is communicated with an external fan;
the fire grate (16) is positioned between the solid collecting water tank (14) and the outer wall (4) of the furnace body, and a gap of a circle between the fire grate (16) and the outer wall (4) of the furnace body is a solid outlet (15);
the end part of the feeding pipe (17) positioned in the outer wall (4) of the furnace body is an inclined plane, the periphery of the inclined plane is provided with a furnace inner baffle (5), the furnace inner baffle (5) is of a major arc structure, the furnace inner baffle (5) is arranged along the plane of the inclined plane, the inner ring of the furnace inner baffle (5) is connected with the feeding pipe (17), the outer ring of the furnace inner baffle is connected with the inner wall of the outer wall (4) of the furnace body, the opening of the furnace inner baffle (5) is positioned on the lower side of the inclined plane of the feeding pipe (17) to form a bed layer synthetic gas outlet (11), and the peripheral area of the feeding pipe (17) on the upper part of the furnace inner baffle (5) is a synthetic gas flow channel (10).
2. The improved updraft biomass gasification unit of claim 1, wherein: the end part of the feeding pipe (17) positioned outside the outer wall (4) of the furnace body is provided with a biomass buffer bin (7), and the biomass buffer bin (7) is externally connected with a feeding screw (8) used for feeding biomass.
3. The improved updraft biomass gasification unit of claim 1, wherein: and an observation hole (9) is also formed in the top of the outer wall (4) of the furnace body.
4. The improved updraft biomass gasification unit of claim 1, wherein: air distributing openings (12) are distributed on the fire grate (16), and an air distributing device (13) is arranged in the fire grate (16).
5. The improved updraft biomass gasification unit of claim 1, wherein: the position of the outer wall (4) of the furnace body, which is close to the fire grate (16), is provided with a water vapor inlet (3).
6. The improved updraft biomass gasification unit of claim 1, wherein: the inner wall circumference of furnace body outer wall (4) bottom is equipped with bed throat (2) that are used for dwindling living beings and directly drop the space.
7. The improved updraft biomass gasification unit of claim 1, wherein: the outer wall (4) of the furnace body is of a cylindrical structure, and the gap width of the solid outlet (15) is 1/15-1/10 of the diameter of the outer wall (4) of the furnace body.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211390137.3A CN115851319A (en) | 2022-11-08 | 2022-11-08 | Improved updraft biomass gasification device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211390137.3A CN115851319A (en) | 2022-11-08 | 2022-11-08 | Improved updraft biomass gasification device |
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| Publication Number | Publication Date |
|---|---|
| CN115851319A true CN115851319A (en) | 2023-03-28 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211390137.3A Pending CN115851319A (en) | 2022-11-08 | 2022-11-08 | Improved updraft biomass gasification device |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116624862A (en) * | 2023-07-21 | 2023-08-22 | 光大环境科技（中国）有限公司 | Biomass gasification synthetic gas direct-combustion heat supply device and processing method |
-
2022
- 2022-11-08 CN CN202211390137.3A patent/CN115851319A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116624862A (en) * | 2023-07-21 | 2023-08-22 | 光大环境科技（中国）有限公司 | Biomass gasification synthetic gas direct-combustion heat supply device and processing method |
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