Low tar, low phenol water multi-medium fixed bed gasifier

Abstract

The application discloses a low-tar, low-phenol water multi-medium fixed bed gasification furnace, which comprises a furnace body, a feeding inlet arranged at the upper end of the furnace body, and a slag discharge outlet arranged at the bottom of the furnace body; a membrane water cooling wall is arranged in the furnace body and arranged along the axial direction of the furnace body; the membrane water cooling wall is located at the upper portion of the furnace body, and an annular cavity is formed between the side wall of the membrane water cooling wall and the side wall of the furnace body; a steady flow gas injection lance and a high-temperature gas small outlet are arranged on the side wall of the membrane water cooling wall in the circumferential direction; a gasification agent nozzle is arranged on the lower side wall of the furnace body; and a slag pool is tightly connected to the lower portion of the furnace body. By using the application, the gasification efficiency can be effectively improved, and the content of the fixed bed tar and phenol water can be greatly reduced.

Description

Technical Field

[0001] This invention relates to the field of gasifier technology, specifically to a low-tar, low-phenol-water multi-medium fixed-bed gasifier. Background Technology

[0002] Traditional fixed-bed gasifiers have a coal / organic solid waste / biomass inlet and a gas outlet at the top. Lump coal / organic solid waste / biomass is added through the inlet, where it exchanges heat countercurrently with the high-temperature gas generated during gasification. The gas undergoes drying, pyrolysis, gasification, and finally oxidation and combustion from top to bottom. The resulting mixture of gasification fuel, tar, and water vapor is discharged through the gas outlet.

[0003] In actual production, although the fixed-bed gasifier uses lump coal / organic solid waste / biomass as feed, dust is carried out with the gas flow due to entrainment of coal / organic solid waste / biomass powder or substandard particle size of lump coal / organic solid waste / biomass, forming tar residue and increasing the difficulty of tar removal. All product gas is discharged from the top of the gasifier and, after being cooled and washed by spray water, requires subsequent oil-water separation, flash evaporation, and phenol water treatment. Although the tar and phenol content in the gasification section products is low, passing all of it into the dry distillation section dilutes the tar content in the fuel gas, increasing the difficulty of extraction; at the same time, due to the increased volume of gas requiring cooling and washing, the amount of phenol-containing wastewater to be treated also increases accordingly. Summary of the Invention

[0004] To address the problems existing in the prior art, the present invention provides a low-tar, low-phenolic water multi-medium fixed-bed gasifier, which can improve gasification efficiency and significantly reduce the content of fixed-bed tar and phenolic water.

[0005] Therefore, the present invention provides the following technical solution:

[0006] A low-tar, low-phenol water-based multi-medium fixed-bed gasifier includes a furnace body, a feed inlet at the upper end of the furnace body, and a slag outlet at the bottom of the furnace body. A membrane water-cooled wall is arranged axially along the furnace body within the furnace body, located at the upper part of the furnace body, and the sidewall of the membrane water-cooled wall forms an annular cavity with the sidewall of the furnace body. A steady-flow gas spray gun and a high-temperature gas outlet are circumferentially arranged on the sidewall of the membrane water-cooled wall. The steady-flow gas spray gun passes through the membrane water-cooled wall and the sidewall of the furnace body. A gasifying agent nozzle is arranged on the lower sidewall of the furnace body. A slag pool is securely connected to the lower part of the furnace body.

[0007] Preferably, a slag discharge pipe is provided on the side wall or bottom of the slag pool, the inlet of the slag discharge pipe is higher than the bottom surface of the slag pool, a combustion torch is provided on the side wall of the furnace body, and the outlet of the slag discharge pipe and the outlet of the combustion torch are located in the fireproof cover.

[0008] Preferably, the combustion nozzle has a multi-channel structure, which includes a central pipe for introducing gas and an outer ring pipe located on the outer periphery of the central pipe for introducing air.

[0009] Preferably, there are multiple constant flow gas spray guns and high temperature gas outlets, which are evenly arranged circumferentially along the side wall of the membrane water-cooled wall.

[0010] Preferably, the membrane water-cooled wall comprises three sections: an upper section, a middle section, and a lower section; the upper section is a section with a gradually decreasing diameter, the middle section is a section with a small diameter, and the lower section is a section with a gradually increasing diameter; the steady-flow gas spray gun is disposed in the upper section of the membrane water-cooled wall; and the high-temperature gas small outlet is disposed in the lower section of the membrane water-cooled wall.

[0011] Preferably, the inner surface of the upper section of the membrane water-cooled wall is provided with refractory material.

[0012] Preferably, the angle between the steady-flow gas spray gun and the horizontal plane is 0 to 90°, and the angle between the high-temperature gas outlet and the horizontal plane is 0 to 90°.

[0013] Preferably, a high-temperature gas outlet for connecting a waste heat recovery boiler is provided on the upper side wall of the furnace body.

[0014] Preferably, the slag pool includes a molten slag pool and a slag storage pool; the molten slag pool is inverted conical shape and is tightly connected to the bottom of the lower section of the membrane water-cooled wall, and the bottom of the molten slag pool is tightly connected to the slag storage pool.

[0015] Preferably, the sidewalls of the slag pool are provided with refractory material and water-cooled walls from the inside out.

[0016] Preferably, a quench chamber is provided at the bottom of the slag pool, and a fireproof cover with an opening facing downward is fastened to the outer wall of the slag pool. A flue gas exhaust pipe is provided inside the quench chamber, with the inlet end of the flue gas exhaust pipe extending into the fireproof cover and the outlet end of the flue gas exhaust pipe passing through the side wall of the furnace body.

[0017] Preferably, the quench chamber is filled with coolant, the opening end of the fireproof cover is lower than the liquid level of the coolant, the inlet end of the flue gas exhaust pipe is higher than the liquid level of the coolant and is disposed in the fireproof cover, the flue gas exhaust pipe is provided with a vent valve for controlling exhaust, and the pipe of the flue gas exhaust pipe is coiled in the coolant.

[0018] Preferably, the fireproof cover is cylindrical, and the fireproof cover adopts an air-cooled structure with a gas outlet on the inner wall.

[0019] The low-tar, low-phenolic water multi-medium fixed-bed gasifier provided in this invention achieves in-situ tar conversion by axially arranging a membrane water-cooled wall inside the furnace body, and uniformly arranging steady-flow gas spray guns along the circumference on the side wall of the membrane water-cooled wall, thereby significantly reducing the tar and phenolic water content. Furthermore, multiple high-temperature gas outlets are uniformly arranged along the circumference on the side wall of the membrane water-cooled wall. Since the high-temperature gas does not contain tar or phenolic water, the purification process is simple and can effectively improve gasification efficiency and quality. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0021] Figure 1 This is a schematic diagram of the structure of a low-tar, low-phenol water multi-media fixed-bed gasifier according to an embodiment of the present invention.

[0022] Numbers in the attached drawings:

[0023] 1. Feeding inlet; 2. Furnace body; 3. Membrane water-cooled wall; 4. High-temperature gas outlet; 5. Gasifying agent nozzle; 6. Flameproof cover; 7. Combustion torch; 8. Slag discharge pipe; 9. Flue gas emission pipe; 10. Slag discharge outlet; 11. Quenching chamber; 12. Slag storage tank; 13. Molten slag tank; 14. High-temperature gas outlet; 15. Steady flow gas torch. Detailed Implementation

[0024] To enable those skilled in the art to better understand the embodiments of the present invention, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and implementation methods.

[0025] like Figure 1 As shown, the low-tar, low-phenol water multi-media fixed-bed gasifier provided in this embodiment includes: a furnace body 2, a feeding inlet 1 at the upper end of the furnace body, and a slag discharge outlet 10 at the bottom of the furnace body 2, through which condensed slag can be discharged from the gasifier.

[0026] In this embodiment of the invention, a membrane water-cooled wall 3 is arranged axially along the furnace body 2 inside the furnace body 2. An annular cavity is formed between the sidewall of the membrane water-cooled wall 3 and the sidewall of the furnace body 2. A steady-flow gas spray gun 15 and a high-temperature gas outlet 4 are arranged circumferentially on the sidewall of the membrane water-cooled wall 3. The steady-flow gas spray gun 15 passes through the membrane water-cooled wall 3 and the sidewall of the furnace body 2. A gasifying agent nozzle 5 is provided on the lower sidewall of the furnace body 2, and a slag pool is securely connected to the lower part of the furnace body 2.

[0027] There can be multiple stable flow gas spray guns 15 and high temperature gas outlets 4, which are evenly arranged along the circumference of the side wall of the membrane water-cooled wall 3.

[0028] The membrane water-cooled wall 3 is designed with three different structures: an upper section, a middle section, and a lower section. The upper section is a section with a gradually decreasing diameter, the middle section is a section with a small diameter, and the lower section is a section with a gradually increasing diameter. The inner surface of the upper section of the membrane water-cooled wall is covered with refractory material.

[0029] Accordingly, the steady-flow gas spray gun 15 can be located in the upper section of the membrane water-cooled wall, for example, in the upper part of the upper section; the high-temperature gas outlet 4 can be located in the lower section of the membrane water-cooled wall, for example, in the upper part of the lower section. Furthermore, the angle between the steady-flow gas spray gun 15 and the horizontal plane can be designed to be 0–90°, and similarly, the angle between the high-temperature gas outlet 4 and the horizontal plane can also be designed to be 0–90°.

[0030] Furthermore, in order to better recover and utilize the waste heat inside the furnace, a high-temperature gas outlet 14 can be provided on the upper side wall of the furnace body 2. In this way, the high-temperature gas outlet 14 is connected to the waste heat boiler for waste heat recovery, so that the high-temperature gas discharged from multiple high-temperature gas outlets 4 can eventually be collected at the high-temperature gas outlet 14, making better use of the waste heat inside the waste heat boiler, which is energy-saving and environmentally friendly.

[0031] The gasifying agent added by the gasifying agent nozzle 5 and the steady flow gas spray gun 15 reacts with the gasification raw material added from the feeding inlet 1. A portion of the high-temperature gas formed by the reaction is directly discharged from the furnace body 2 through the high-temperature gas outlet 14.

[0032] like Figure 1 As shown, in this embodiment of the invention, the slag pool includes a molten slag pool 13 and a slag storage pool 12. The lower section of the membrane water-cooled wall 3 is tightly connected to the bottom of the molten slag pool 13, which has a uniform wall thickness and is inverted conical in shape. The slag storage pool 12 is tightly connected to the bottom of the molten slag pool 13; for example, the upper end of the slag storage pool 12 can be connected to the lower end of the molten slag pool 13 via a flange. The sidewalls of both the molten slag pool 13 and the slag storage pool 12 are provided with refractory material and water-cooled walls from the inside out. The refractory material needs to have strong resistance to slag and molten iron erosion; for example, microporous corundum bricks, carbon composite bricks, or silon-bonded corundum bricks are preferred.

[0033] A slag discharge pipe 8 is installed on the side wall or bottom of the slag storage tank 12. The inlet of the slag discharge pipe 8 is higher than the bottom surface of the slag storage tank 12. Therefore, the iron precipitated in the liquid slag is deposited at the bottom of the slag storage tank 12, thereby effectively preventing the outlet of the slag discharge pipe 8 from being blocked due to iron precipitation in the liquid slag. The angle between the centerline of the slag discharge pipe 8 and the horizontal plane is greater than or equal to 0° and less than 90°. The slag discharge pipe 8 can be a single casting with a water-cooled structure. It is fixed to the slag storage tank 12 by a flange, which allows for easy replacement when the slag discharge pipe 8 is damaged.

[0034] Furthermore, a combustion torch 7 is installed on the side wall of the furnace body 2. The outlet of the slag discharge pipe 8 and the outlet of the combustion torch 7 are located in the fireproof cover 6. The hot flue gas generated by the combustion torch 7 enters the slag storage tank through the slag discharge pipe 8, ensuring that the liquid slag in the slag storage tank 12 is in a good flow state to prevent the liquid slag from condensing in the slag discharge pipe 8, and also playing a role in supporting the slag.

[0035] Furthermore, a quench chamber 11 is provided at the bottom of the slag storage tank 12, and a fireproof cover 6 with an opening facing downwards is fastened to the outer wall of the slag storage tank 12. A flue gas exhaust pipe 9 is provided inside the quench chamber 11. The inlet end of the flue gas exhaust pipe 9 extends into the fireproof cover 6, and the outlet end of the flue gas exhaust pipe 9 passes through the side wall of the furnace body 2 to discharge the flue gas generated by combustion to the outside.

[0036] In the above embodiment, the quench chamber 11 is filled with coolant. The open end of the flame shield 6 is lower than the surface of the coolant, forming a water seal between the flame shield 6 and the surface of the coolant. The inlet end of the flue gas exhaust pipe 9 is higher than the surface of the coolant. A vent valve for controlling exhaust is installed on the flue gas exhaust pipe 9, and the pipe of the flue gas exhaust pipe 9 is coiled in the coolant in the quench chamber 11. When the pressure difference between the upper part of the slag pool 13 and the inside of the flame shield 6 reaches a certain value, the vent valve opens, and the flue gas exhaust pipe 9 discharges flue gas, thereby controlling the pressure inside the flame shield 6.

[0037] The gasification feedstock added through the feed inlet 1 reacts with the gasifying agent added through the gasifying agent nozzle 5 and the steady-flow gas injection gun 15. The gasifying agent is one or a mixture of oxygen, water vapor, air, carbon dioxide, etc. The gasifying agent ratio of the gasifying agent nozzle 5 and the steady-flow gas injection gun 15 is adjusted according to the furnace conditions.

[0038] In the above embodiments, the fireproof cover 6 is cylindrical, such as cubic or cylindrical. The fireproof cover 6 adopts an air-cooled structure and has a gas outlet on its inner wall to prevent the fireproof cover 6 from being burned. The fireproof cover 6 prevents the high-temperature flue gas generated by combustion from corroding the flange connecting the molten slag pool 13 and the slag storage pool 12, thus protecting the flange connection.

[0039] In the above embodiment, the combustion torch 7 extends into the quench chamber 11 through a channel on the side wall of the quench chamber. The combustion torch 7 adopts a multi-channel structure, which includes a central pipe for introducing gas and an outer ring pipe for introducing air located on the outer periphery of the central pipe. When replacing the combustion torch 7, it can be directly pulled out of the furnace, which is convenient to operate.

[0040] The following will continue to combine Figure 1 This invention provides a detailed explanation of the working principle of the multi-medium fixed-bed slag gasifier according to embodiments of the present invention.

[0041] Reference Figure 1Coolant is poured into the quench chamber 11 until the liquid level is higher than the lower port of the flameproof cover 6. Gasification feedstock is added to the gasifier through the feed inlet 1. The gasifying agent sprayed from the steady-flow gas torch 15 reacts with the gasification feedstock to remove tar from the gasification feedstock. The gasifying agent sprayed from the gasifying agent nozzle 5 reacts with the gasified feedstock again to form a high-temperature slag zone. The high-temperature gas formed by the gasification reaction is collected through the high-temperature gas outlet 4 at the bottom of the membrane water-cooled wall and discharged from the gasifier through the high-temperature gas outlet 14.

[0042] The liquid slag produced during the gasification process in the gasifier is collected in the slag storage tank 12 through the slag pool 13 and accumulates continuously in the slag storage tank 12; the hot flue gas generated by the combustion torch 7 enters the slag storage tank 12 through the slag discharge pipe 8, ensuring that the liquid slag in the slag storage tank 12 is in a good flow state to prevent the liquid slag from condensing in the slag discharge pipe 8, and also plays a role in supporting the slag.

[0043] When the pressure difference between the upper part of the slag pool 13 and the inside of the flame shield 6 reaches a certain value, the vent valve on the flue gas exhaust pipe 9 is opened to reduce the pressure in the flame shield 6, and at the same time the gas flow rate of the combustion torch 7 is reduced to discharge slag; when the pressure difference between the upper part of the slag pool 13 and the inside of the flame shield 6 decreases to a certain value, the vent valve on the flue gas exhaust pipe 9 is closed, and at the same time the gas flow rate of the combustion torch 7 is increased to stop discharging slag. In summary, one slag discharge process is completed.

[0044] In the event of an emergency shutdown during gasifier operation, the flow rate of gas injected into the gasifier by the combustion nozzle 7 is controlled to prevent liquid slag from entering the slag discharge pipe 8, condensing and causing blockage, which would affect the restart of the gasifier.

[0045] The multi-medium fixed-bed gasifier provided in this embodiment of the invention has the following advantages:

[0046] 1. The furnace body of the present invention is provided with a membrane water-cooled wall in the axial direction. The side wall of the membrane water-cooled wall is uniformly provided with a steady flow gas spray gun along the circumference to realize the in-situ conversion of tar and significantly reduce the tar content. In addition, multiple high-temperature gas outlets are uniformly provided along the circumference of the side wall of the membrane water-cooled wall. Since the high-temperature gas does not contain tar, the purification process is simple.

[0047] 2. This invention achieves in-furnace conversion of tar and phenolic water by using a gasifying agent sprayed from a steady-flow gas nozzle to react with the gasification raw materials. This reduces the phenol content in the high-temperature gas discharged directly from the high-temperature gas outlet, thereby reducing the amount of phenol-containing wastewater to be treated and improving work efficiency.

[0048] 3. In this invention, the slag discharge pipe is installed on the slag storage tank. The outlet of the slag discharge pipe and the outlet of the fuel spray gun are installed inside a fireproof cover with a sealed top and an open bottom. A fireproof cover with an opening facing downward is fastened to the outer wall of the slag storage tank. The open end of the fireproof cover is located below the surface of the coolant. The hot flue gas generated by the combustion spray gun enters the slag storage tank through the slag discharge pipe. Therefore, the liquid slag in the slag storage tank is in a good flow state to prevent the liquid slag from condensing in the slag discharge pipe, and it also plays a role in supporting the slag.

[0049] 4. The slag pool of this invention adopts a split structure, consisting of a molten slag pool and a slag storage pool. This structural design facilitates installation and maintenance. Only easily damaged parts can be replaced, reducing the cost of maintaining the slag pool.

[0050] 5. In this invention, the inlet of the slag discharge pipe is higher than the bottom of the slag pool, so that the iron precipitated in the liquid slag is deposited at the bottom of the slag pool and does not settle in the slag discharge pipe, thus effectively avoiding slag discharge pipe blockage caused by iron precipitation.

[0051] 6. The combustion nozzle of the present invention extends into the quench chamber through a channel on the side wall of the quench chamber, thus making it convenient to operate when the combustion nozzle needs to be repaired or replaced.

[0052] 7. In this invention, the fireproof cover prevents the high-temperature flue gas generated by the combustion of the internal combustion torch from corroding the flange connecting the molten slag pool and the slag storage pool, thus effectively protecting the flange.

[0053] 8. The slag zone and annular slag trough of the present invention adopt a water-cooled wall structure, which can greatly improve the service life of refractory materials.

[0054] 9. The slag discharge port adopts an inverted cone-shaped structure, which can reduce the thickness of slag hanging at the slag discharge port and prevent the slag discharge port from being blocked due to excessive slag hanging.

[0055] The embodiments of the present invention have been described in detail above. Specific implementation methods have been used to illustrate the present invention. The descriptions of the embodiments above are only for the purpose of helping to understand the present invention, and are merely some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention. The content of this specification should not be construed as a limitation of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A low-tar, low-phenol-water multi-media fixed-bed gasifier, comprising a furnace body, a feeding inlet at the upper end of the furnace body, and a slag outlet at the bottom of the furnace body; characterized in that: A membrane water-cooled wall is provided in the furnace body and arranged along the axial direction of the furnace body. The membrane water-cooled wall is located in the upper part of the furnace body, and the side wall of the membrane water-cooled wall and the side wall of the furnace body form an annular cavity. A steady-flow gas spray gun and a small high-temperature gas outlet are arranged circumferentially on the side wall of the membrane water-cooled wall; the steady-flow gas spray gun passes through the membrane water-cooled wall and the side wall of the furnace body; a gasifying agent nozzle is arranged on the lower side wall of the furnace body; a slag pool is fastened to the lower part of the furnace body. The membrane water-cooled wall comprises three sections: an upper section, a middle section, and a lower section; the upper section is a section with a gradually decreasing diameter, the middle section is a section with a small diameter, and the lower section is a section with a gradually increasing diameter; the steady-flow gas spray gun is located in the upper section of the membrane water-cooled wall; and the high-temperature gas small outlet is located in the lower section of the membrane water-cooled wall. The furnace body is provided with a combustion nozzle on its side wall. The combustion nozzle adopts a multi-channel structure, which includes a central pipe for introducing gas and an outer ring pipe for introducing air located on the outer periphery of the central pipe. The angle between the steady flow gas nozzle and the horizontal plane is 0 to 90°, and the angle between the high temperature gas outlet and the horizontal plane is 0 to 90°. The slag pool is provided with a slag discharge pipe on its side wall or bottom. The inlet of the slag discharge pipe is higher than the bottom surface of the slag pool, and the outlet of the slag discharge pipe and the outlet of the combustion spray gun are arranged in a fireproof cover.

2. The low-tar, low-phenolic water-based multi-medium fixed-bed gasifier according to claim 1, characterized in that, The inner surface of the upper section of the membrane water-cooled wall is provided with refractory material.

3. The low-tar, low-phenolic water-based multi-medium fixed-bed gasifier according to claim 1, characterized in that, A high-temperature gas outlet for connecting a waste heat recovery boiler is provided on the upper side wall of the furnace body.

4. The low-tar, low-phenolic water-based multi-medium fixed-bed gasifier according to any one of claims 1 to 3, characterized in that, A quench chamber is provided at the bottom of the slag pool. The fireproof cover is opened downwards and is fastened to the outer wall of the slag pool. A flue gas exhaust pipe is provided inside the quench chamber. The inlet end of the flue gas exhaust pipe extends into the fireproof cover, and the outlet end of the flue gas exhaust pipe passes through the side wall of the furnace body.

5. The low-tar, low-phenolic water-based multi-medium fixed-bed gasifier according to claim 4, characterized in that, The quench chamber is filled with coolant. The opening end of the fireproof cover is lower than the liquid level of the coolant. The inlet end of the flue gas exhaust pipe is higher than the liquid level of the coolant and is located in the fireproof cover. The flue gas exhaust pipe is equipped with a vent valve to control exhaust. The pipe of the flue gas exhaust pipe is coiled in the coolant.

6. The low-tar, low-phenolic water-based multi-medium fixed-bed gasifier according to claim 4, characterized in that, The fireproof cover is cylindrical and adopts an air-cooled structure with a gas outlet on its inner wall.

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