Fixed bed gasifier

Abstract

The utility model discloses a fixed bed gasification furnace which comprises a furnace body, the side wall of the furnace body comprises an inner interlayer and an outer interlayer, an ash tray is arranged at the bottom of the furnace body, a feed port is formed in the top of the furnace body, a finished gas outlet is formed in the upper part of the outer interlayer of the furnace body, three equally-divided gasification agent inlets are distributed on the circumference of the lower part of the inner interlayer, and the three gasification agent inlets are connected to an air inlet header pipe; the extension line of the air outlet end of the air inlet pipeline and the center line of the furnace body form an included angle. And a temperature sensor is arranged in the furnace body close to the air inlet pipeline. A rotary air distributor is formed through an air inlet pipeline inserted into a furnace body, air which rotates downwards and is uniformly distributed is formed in the furnace, water vapor and dry distillation gas generated by a drying layer and a dry distillation layer are brought into a high-temperature reaction area, and after oxygen, the dry distillation gas and the water vapor are consumed and decomposed, the oxygen, the dry distillation gas and the water vapor are converted into clean combustible gas containing hydrogen, carbon monoxide, methane and the like; and after exchanging heat with inner interlayer air through an interlayer outlet at the lower part of the gasification furnace, conveying to a purification system to serve as fuel gas or chemical green product raw materials such as downstream synthetic green alcohol and the like.

Description

Technical Field

[0001] The utility model relates to the technical field of biomass gasification, in particular to a fixed-bed gasifier. Background Technique

[0002] Biomass gasification is an important method for the utilization of biomass energy. It refers to the process of carrying out chemical reactions with a certain amount of gasifying agent (such as air or water vapor, etc.) at a relatively high reaction temperature to generate combustible gases such as CO, H 2 , CH 4 and hydrocarbons. The main problem of the current biomass gasification technology is that the tar content in the generated biomass gas is high, which greatly reduces the calorific value of the gas. The combined action of tar and fly ash in the gas blocks the gas transmission pipeline and damages the gasification and purification equipment; when purifying and washing the gas, the phenolic water generated by cooling cannot be directly discharged, and the treatment cost is high. The tar recovered and the odor generated by the volatilization of the high-temperature circulating water pollute the environment. At present, the down-draft gasification method with low tar content in the gas has very low gasification efficiency. Therefore, developing a new type of high-efficiency low-tar biomass gasification reactor is of great significance for the efficient and clean utilization of large-scale biomass energy. Content of the Utility Model

[0003] The purpose of the utility model is to provide a fixed-bed gasifier. Through the intake pipe inserted into the furnace body, a rotary air distributor is formed to form uniformly rotating downward air in the furnace. Combined with the temperature sensor and the adjustment of the ash discharge speed of the rotatable ash pan, the coexistence mode of up-draft and down-draft in the gasifier is achieved, and a dynamic balance is reached, so that the material burns sufficiently while improving the gasification rate.

[0004] To achieve the above purpose, the utility model provides the following technical solutions:

[0005] A fixed-bed gasifier includes a furnace body. The side wall of the furnace body includes an inner interlayer and an outer interlayer. The bottom of the furnace body is provided with an ash pan, the top is provided with a feeding port, the upper part of the outer interlayer of the furnace body is provided with a finished gas outlet, and the lower part of the inner interlayer is circumferentially and uniformly provided with gasifying agent inlets; the gasifying agent inlets are connected with air inlet pipes; the extension line of the outlet end of the air inlet pipe forms an angle with the center line of the furnace body; a temperature sensor is also provided in the furnace body near the air inlet pipe.

[0006] Further scheme: The angle is 15-30°.

[0007] Further scheme: The outlet end of the air inlet pipe has a downward inclined section.

[0008] Further scheme: The air inlet pipe includes a vertical section and a horizontal section. The horizontal section is the outlet end, and the length of the horizontal section is 1 / 4 to 1 / 2 of the inner diameter of the furnace body.

[0009] Further solution: A secondary air inlet pipe is connected between the feeding port and the furnace body.

[0010] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0011] Through the unique design of the air inlet pipe, the present utility model forms a stable downward swirling airflow in the furnace, with uniform air distribution. The space in the furnace from the upper part of the air inlet pipe to the feeding port can be used as a storage bin, and a gate valve switch is arranged at the bottom for feeding. The storage capacity is large, and the feeding interval time is long, which is very beneficial for the detection of the material level. Description of the drawings

[0012] Figure 1 It is a side sectional view of the present utility model;

[0013] Figure 2 It is a top view of the furnace body and the air inlet pipe in the present utility model;

[0014] In the figure: 1 - furnace body, 11 - inner sandwich layer, 12 - outer layer, 2 - ash pan, 3 - feeding port, 4 - finished gas outlet, 5 - air inlet pipe, 51 - horizontal section, 52 - vertical section, 6 - secondary air inlet pipe, 7 - temperature sensor. Specific implementation manners

[0015] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0016] In the description of the present utility model, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the product of the present utility model is usually placed. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present utility model.

[0017] Please refer to Figure 1-2, in this embodiment, a fixed-bed gasifier includes a furnace body 1. A ash pan 2 is provided at the bottom of the furnace body 1, a feeding port 3 is provided at the top, a finished gas outlet 4 is provided at the upper part of the side wall of the furnace body 1, and four gasifying agent inlets are circumferentially and evenly distributed at the lower part of the side wall; the gasifying agent inlets are connected with air inlet pipes 5; the extension line of the air outlet end of the air inlet pipe 5 forms an angle with the central axis of the furnace body 1; and, a rotary air distributor is provided at the air outlet end of the air inlet pipe 5. The inclined section of the air inlet pipe 5 faces downward, and local holes are naturally formed below to facilitate air diffusion, and the material is not easily blocked. With the assistance of the rotary air distributor, a downward-rotating air flow is formed in the furnace, and the air distribution uniformity is good. A temperature sensor 8 is also provided in the furnace body 1 near the air inlet pipe 5. The temperature sensor 8 is set as a thermocouple. Two K-type thermocouples are provided at 400 mm and 600 mm below the air inlet pipe 5 of the gasifier respectively, which are used to measure the temperature of the material layer at 400 mm and 600 mm away from the air inlet, to guide the control of the ash pan rotation speed, and thus control the gasification efficiency. At the same time, the firm air inlet pipe protects the safety of the thermocouple sleeve.

[0018] Further, the air inlet pipe 5 includes a vertical section and a horizontal section. The horizontal section 51 is the air outlet end, and, the length of the horizontal section 51 is 1 / 4 to 1 / 2 of the inner diameter of the furnace body 1, preferably 1 / 3.

[0019] Further, the above-mentioned angle is 15 - 30°. The extension lines of the air outlet directions of the four air inlet pipes 5 are connected to form a square. Under the action of the rotary air distributor, a stable downward-rotating air flow is formed.

[0020] Further, a temperature sensor 8 is also provided in the furnace body 1 near the air inlet pipe 5. The temperature sensor 8 is set as two thermocouples, which are used to measure the temperature of the material layer at 400 mm and 600 mm away from the air inlet.

[0021] Further, a secondary air inlet pipe 6 is connected between the feeding port 3 and the furnace body 1. The secondary air inlet pipe 6 serves as a supplementary port for the gasifying agent and plays a role in promoting the balanced air distribution.

[0022] Further, the ash pan 2 is rotatably arranged. The faster the rotation speed of the ash pan 2, the faster the ash discharge speed. The thermocouple guides the control of the ash pan rotation speed according to the measured temperature of the material layer, and thus controls the gasification efficiency.

[0023] The working principle of the present utility model is as follows: When the rotation speed of the ash pan 2 is too fast, the material layer moves downward faster, the natural replenishment amount of the material is large, the oxidation layer moves downward, and the gasification reaction will convert into a pure downward suction mode, resulting in a decrease in gasification efficiency; while when the speed of the ash pan is too slow, the natural replenishment amount of the material is small, the oxidation layer moves upward, and when the feed of the oxidation layer is insufficient, the carbon content will gradually decrease, the oxidation reaction speed slows down, and the oxygen in the gasifying agent cannot be completely consumed. Then the oxygen will enter the ash residue close to the lower part of the oxidation layer and react with the residual carbon in the ash residue to form a gasification mode with both upward suction reaction and downward suction reaction. The effect obtained by this patent is to maintain the continuity of this state, improve the gasification efficiency, and reduce the tar and moisture content in the gas; Therefore, under the guidance of the temperature sensor, when the temperature at the upper measuring point is too high, it indicates that the rotation speed of the ash pan is fast, the feeding amount is large, the oxidation reaction is intense, and the carbon below obtains less oxygen. Control the ash discharging speed to slow down, reduce the feeding amount, lower the temperature at the upper measuring point, and maintain the ideal gasification mode with both upward suction reaction and downward suction reaction; when the temperature at the lower measuring point is high, it indicates that the carbon layer below obtains more oxygen, and the temperature of the oxidation layer at the upper measuring point drops. Control the ash discharging speed to accelerate, increase the feeding amount, raise the temperature at the upper measuring point, and maintain the ideal gasification mode with both upward suction reaction and downward suction reaction; Therefore, the reduction and cracking effect is obvious, the material burns fully, the carbon content in the ash residue decreases, the gasification efficiency is close to that of the upward suction type gasification, and the efficiency is greatly improved.

[0024] When the present utility model is in operation, the space in the furnace from the upper part of the air inlet pipe 5 to the feeding port 3 serves as a storage bin. Air enters the furnace body 1 from the air inlet pipe 5, and the ash formed after the combustion of the biomass material falls downward into the ash pan 2. The ash pan 2 rotates and discharges the ash out of the furnace body 1. Along with the simultaneous ash discharging and material replenishment, the oxidation layer is below the air inlet pipe 5, maintaining the ideal gasification mode with both upward suction reaction and downward suction reaction. The temperature sensor 8 monitors the temperature in the furnace in real time and guides the ash discharging speed to make the oxidation layer reach a dynamic balance. Under the thermal radiation effect of the oxidation layer, the water vapor and dry distillation gas generated by the material are decomposed through the oxidation layer, and together with the carbon monoxide, hydrogen, etc. formed by the oxidation-reduction reaction, a mixed gas is formed, which finally enters the purification section from the outlet 4. The secondary air inlet pipe 6 serves as an air supplement port and promotes the uniform distribution of air.

[0025] Although this specification is described according to the implementation manners, not every implementation manner only contains an independent technical solution. This narrative manner of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other implementation manners that can be understood by those skilled in the art.

[0026] Therefore, the above description is only the preferred embodiment of the present application and is not used to limit the scope of implementation of the present application; that is, all equivalent transformations made according to the scope of the claims of the present application are within the protection scope of the claims of the present application.

Claims

1. A fixed bed gasification furnace, comprising a furnace body (1), wherein the side wall of the furnace body (1) comprises an inner interlayer (11) and an outer interlayer (12), characterized in that: The bottom of the furnace body (1) is provided with an ash tray (2) for receiving and discharging ash, the top is provided with a charging port (3), the upper part of the outer interlayer of the furnace body (1) is provided with a finished gas outlet (4), and the lower part of the inner interlayer is provided with gasifying agent inlets evenly distributed in the circumferential direction; the gasifying agent inlet is connected to an air inlet duct (5); the extended line of the air outlet end of the air inlet duct (5) forms an angle with the center line of the furnace body (1); and a temperature sensor (7) is also provided in the furnace body (1) near the air inlet duct (5).

2. The fixed bed gasifier according to claim 1, characterized in that: The angle is 15-30°.

3. The fixed bed gasifier according to claim 1, characterized in that: The air outlet end of the air inlet duct (5) has a downward beveled surface.

4. The fixed bed gasifier according to claim 1, characterized in that: The air inlet duct (5) comprises a vertical section and a horizontal section, the horizontal section (51) is an air outlet end, and the length of the horizontal section (51) is 1 / 4 to 1 / 2 of the inner diameter of the furnace body (1).

5. The fixed bed gasifier according to claim 1, characterized in that: A secondary air inlet duct (6) is connected between the feed port (3) and the furnace body (1).

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