An air supplement device for a fluidized bed

Abstract

The present invention discloses an air supplementing device for a fluidized bed, comprising: an upper air supplementing chamber and a lower air supplementing chamber. Both the upper air supplementing chamber and the lower air supplementing chamber are annular cavities and are sleeved outside the fluidized bed. The fluidized bed successively includes a large-diameter section riser, a variable-diameter section, and a small-diameter section riser from top to bottom. The upper air supplementing chamber is sleeved on the lower part of the large-diameter section riser, and the upper part of the variable-diameter section is located inside the upper air supplementing chamber. The lower air supplementing chamber is sleeved on the upper part of the small-diameter section riser, and the lower part of the variable-diameter section is located inside the lower air supplementing chamber. A first air supplementing inlet is formed on the upper air supplementing chamber, and a second air supplementing inlet is formed on the lower air supplementing chamber; a plurality of first nozzles are arranged on the fluidized bed inside the upper air supplementing chamber, and a plurality of second nozzles are arranged on the fluidized bed inside the lower air supplementing chamber. Both the first nozzles and the second nozzles are located in the variable-diameter section. This air supplementing device can fully solve problems such as uneven reaction in a circulating fluidized bed and high backmixing in a turbulent fluidized bed.

Description

Technical Field

[0001] The present invention belongs to the technical field of circulating fluidized beds, and specifically relates to an air supplement device for a fluidized bed. Background Art

[0002] Fluidized beds have excellent mass transfer, heat transfer characteristics, and high-efficiency and rapid transportation capabilities, and are widely used in various industries such as energy, chemical engineering, pharmaceuticals, food, and the environment. However, in traditional circulating fluidized beds, the particle concentration is low, the gas-solid contact efficiency is low, and the axial and radial flow characteristics are uneven, resulting in insufficient and non-uniform reactions and low conversion rates of products; while in high-density fluidized beds or turbulent fluidized beds, although the particle concentration in the bed is high, serious backmixing phenomena occur in the fluidized bed reactor, leading to severe coking of the catalyst, catalyst failure, and adverse effects on continuous reactions. Summary of the Invention

[0003] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide an air supplement device for a fluidized bed, which can fully solve problems such as uneven reactions in circulating fluidized beds and high backmixing in turbulent fluidized beds.

[0004] The purpose of the present invention is achieved through the following technical solutions.

[0005] An air supplement device for a fluidized bed includes: an upper air supplement chamber and a lower air supplement chamber. Both the upper air supplement chamber and the lower air supplement chamber are annular cavities and are sleeved outside the fluidized bed. The fluidized bed successively includes a large-diameter section riser, a variable-diameter section, and a small-diameter section riser from top to bottom. The upper air supplement chamber is sleeved on the lower part of the large-diameter section riser, and the upper part of the variable-diameter section is located inside the upper air supplement chamber. The lower air supplement chamber is sleeved on the upper part of the small-diameter section riser, and the lower part of the variable-diameter section is located inside the lower air supplement chamber. A first air supplement inlet is formed on the upper air supplement chamber, and a second air supplement inlet is formed on the lower air supplement chamber; a plurality of first nozzles are arranged on the fluidized bed inside the upper air supplement chamber, and a plurality of second nozzles are arranged on the fluidized bed inside the lower air supplement chamber. Both the first nozzles and the second nozzles are located in the variable-diameter section.

[0006] In the above technical solution, a first air supplement chamber ash discharge port is formed on the upper air supplement chamber, and a cover is installed on the first air supplement chamber ash discharge port. A second air supplement chamber ash discharge port is formed on the lower air supplement chamber, and a cover is installed on the second air supplement chamber ash discharge port.

[0007] In the above technical solution, a plurality of convex pyramids are formed on the inner wall of the variable-diameter section.

[0008] In the above technical solution, the pyramid is a triangular pyramid.

[0009] In the above technical solution, the number of the first nozzles is 4 to 12 and they are arranged on the fluidized bed along the circumferential direction, and the number of the second nozzles is 4 to 12 and they are arranged on the fluidized bed along the circumferential direction.

[0010] In the above technical solution, the included angle θ between the inclined plane of the variable diameter section and the horizontal plane is 40 to 89°.

[0011] In the above technical solution, the included angle between the uppermost inclined plane of each pyramid and the inner wall of the variable diameter section where the pyramid is located is 5 to θ°.

[0012] In the above technical solution, the height of the upper air supplement chamber is 0.25 to 1 m, and the height of the lower air supplement chamber is 0.25 to 1 m.

[0013] In the above technical solution, the distance between the first nozzle and the central axis of the fluidized bed is r1, the distance between the second nozzle and the central axis of the fluidized bed is r2, and the radius of the large-diameter section riser is R. Then 0.75 < r1 / R < 1 and 0.5 < r2 / R < 0.75.

[0014] The beneficial effects of the air supplement device of the present invention are as follows:

[0015] 1. Under the action of the air supplement device, a negative pressure area is formed in the upper part of the small-diameter section riser, which improves the pulling effect of the gas-solid fluid in the lower part of the small-diameter section riser, thereby suppressing the occurrence of plugging phenomenon in the lower part of the small-diameter section riser, and enabling the gas-solid flow characteristics in the lower part of the small-diameter section riser to obtain a higher particle concentration and a uniform axial and radial flow effect.

[0016] 2. Under the action of the air supplement device, the upper part of the large-diameter section riser provides a lifting effect for the gas-solid fluid in the upper part of the large-diameter section riser, accelerates the transportation of the gas-solid fluid, and reduces the gas-solid backmixing in the side wall area of the upper part of the large-diameter section riser.

[0017] 3. Under the action of the air supplement device, the solid-fluid flow pattern in the fluidized bed can be partitioned. The small-diameter section riser is a dense phase area with a relatively large solid-gas ratio, presenting a turbulent fluidization flow pattern or a high-density fluidization flow pattern, and the large-diameter section riser is a dilute phase area with a relatively small solid-gas ratio, presenting a fast fluidization or pneumatic conveying flow pattern.

[0018] 4. The setting of the air supplement device can flexibly control the large-diameter section riser and the small-diameter section riser respectively, thereby reducing the probability of side reactions and over-reactions occurring in the large-diameter section riser and the small-diameter section riser, and further improving the yield of the total reaction target product.

[0019] 5. Uniformly distributed conical ribs are provided on the inclined side of the reduced-diameter section, which can impede the flow of the gas-solid mixture flowing downward along the surface of the reduced-diameter section and divert it into the high-speed upward gas-solid main flow in the center of the riser with a large diameter. While accelerating the mixing of oil and agent, it also effectively inhibits the backmixing of the catalyst. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic structural diagram of the novel combined small-diameter section riser fluidized bed reaction device of the present invention;

[0021] Figure 2 is a schematic structural diagram of the air supplement device;

[0022] Figure 3 is a schematic structural diagram of the air supplement device (with a pyramid).

[0023] Among them, 1: compressor, 2: buffer tank, 3: vent valve, 4: first gas flowmeter, 5: gas distributor, 6: small-diameter section riser, 7: pressure sensor, 8: computer, 9: air supplement device, 9-1: second air supplement chamber ash discharge port, 9-2: second air supplement inlet, 9-3: first air supplement inlet, 9-4: first air supplement chamber ash discharge port, 10: fluidized bed, 10-1: first nozzle, 10-2: second nozzle, 11: companion bed, 12: first cyclone separator, 13: second cyclone separator, 14: absorption device, 15: first pipeline, 16: second pipeline, 17: fifth pipeline, 18: fourth pipeline, 19: third pipeline, 20: tenth pipeline, 21: sixth pipeline, 22: first valve, 23: eighth pipeline, 24: ninth pipeline, 25: seventh pipeline. SPECIFIC EMBODIMENTS

[0024] The technical solution of the air supplement device of the present invention will be further described below in conjunction with specific embodiments.

[0025] The gas distributor 5 can adopt the gas-solid distributor in CN201210405627.6.

[0026] Embodiment 1

[0027] The air supplement device is applied to the fluidized bed, that is, a novel combined small-diameter section riser fluidized bed reaction device, as Figure 1As shown in the figure, it includes: a fluidized bed 10, a gas distributor 5, a compressor 1, a gas supplementing device 9, an accessory bed 11 and a buffer tank 2. The compressor 1 is communicated with the air inlet of the buffer tank 2 through a first pipeline 15. The gas distributor 5 is arranged inside the fluidized bed 10. There are two exhaust ports on the buffer tank 2: a first exhaust port and a second exhaust port. The first exhaust port of the buffer tank 2 is communicated with the gas distributor 5 inside the fluidized bed 10 through a second pipeline 16. The top of the fluidized bed 10 is communicated with the first inlet of the accessory bed 11 through a tenth pipeline 20, for introducing a catalyst and a gas product into the accessory bed 11 through the tenth pipeline 20. The first outlet of the accessory bed 11 is communicated with the fluidized bed 10 through a ninth pipeline 24, for introducing a catalyst into the fluidized bed 10. The second outlet of the accessory bed 11 is communicated with the air inlet of a first cyclone separator 12 through a third pipeline 19, for performing gas-solid separation on the substances in the third pipeline 19. Among them, the second outlet is located in the upper part of the accessory bed 11, and the first outlet is located in the lower part of the accessory bed 11.

[0028] The ash discharge port of the first cyclone separator 12 is communicated with the air inlet of a second cyclone separator 13 through a fourth pipeline 18, for performing gas-solid separation on the substances in the fourth pipeline 18. The ash discharge port of the second cyclone separator 13 is communicated with the second inlet of the accessory bed 11 through a fifth pipeline 17, for introducing the catalyst after gas-solid separation into the accessory bed 11. The exhaust ports of the first cyclone separator 12 and the second cyclone separator 13 are both communicated with the outside;

[0029] A catalyst inlet is arranged on the accessory bed 11, and a cover body is installed on the catalyst inlet;

[0030] The gas supplementing device 9 is installed on the fluidized bed 10. The second exhaust port of the buffer tank 2 is communicated with the gas supplementing device 9 through an eighth pipeline 23.

[0031] The compressor transports the raw material gas to the buffer tank, and then enters the gas distributor inside the fluidized bed or enters the gas supplementing device; after the reaction between the catalyst in solid particle state and the raw material gas in the fluidized bed, it enters the accessory bed. Most of the catalyst in the accessory bed is recycled back to the fluidized bed through the ninth pipeline 24, and a small part of the catalyst and the raw material gas are subjected to gas-solid separation by the first cyclone separator and the second cyclone separator; during operation, the gas supplementing device can realize the zoning regulation and control of the fluidized bed state, forming a dense phase region with a relatively large solid-gas ratio (the solid content is between 0.25 and 0.3) in the small-diameter section riser 6, and a dilute phase region with a relatively small solid-gas ratio (the solid content is between 0.03 and 0.08) in the large-diameter section riser.

[0032] The companion bed serves as an intermediate carrier for catalyst storage. The companion bed is arranged vertically higher than the riser with a small diameter section, thus providing power for the catalyst to enter the riser with a small diameter section, thereby increasing the circulation intensity of the riser with a small diameter section, improving the gas-solid contact efficiency, enhancing the axial-radial uniformity of gas-solid flow in the riser with a small diameter section, and increasing the production capacity.

[0033] Example 2

[0034] As Figure 2 and 3 shown, on the basis of Example 1, the air supplement device 9 includes: an upper air supplement chamber and a lower air supplement chamber. Both the upper air supplement chamber and the lower air supplement chamber are annular cavities and are sleeved outside the fluidized bed 10. The fluidized bed 10 successively includes a riser with a large diameter section, a variable diameter section, and a riser with a small diameter section 6 from top to bottom. The upper air supplement chamber is sleeved on the lower part of the riser with a large diameter section and the upper part of the variable diameter section is located inside the upper air supplement chamber. The lower air supplement chamber is sleeved on the upper part of the riser with a small diameter section 6 and the lower part of the variable diameter section is located inside the lower air supplement chamber. A first air supplement inlet 9-3 is formed on the upper air supplement chamber, and a second air supplement inlet 9-2 is formed on the lower air supplement chamber; a plurality of first nozzles 10-1 are arranged on the fluidized bed 10 inside the upper air supplement chamber, and a plurality of second nozzles 10-2 are arranged on the fluidized bed 10 inside the lower air supplement chamber. Both the first nozzles 10-1 and the second nozzles 10-2 are located in the variable diameter section. The first nozzles and the second nozzles arranged in the air supplement device divide the fluidized bed into upper and lower flow pattern zones. The riser with a small diameter section 6 is a dense phase zone with a relatively large solid-gas ratio, presenting a turbulent fluidization flow pattern or a high-density fluidization flow pattern. The riser with a large diameter section is a dilute phase zone with a relatively small solid-gas ratio, presenting a fast fluidization or pneumatic conveying flow pattern.

[0035] The gas first enters the upper air supplement chamber and the lower air supplement chamber through the eighth pipeline 23, and then enters the fluidized bed through the first nozzles and the second nozzles.

[0036] The number of the first nozzles 10-1 is 4 to 12 and is arranged on the fluidized bed 10 along the circumferential direction. The number of the second nozzles 10-2 is 4 to 12 and is arranged on the fluidized bed 10 along the circumferential direction.

[0037] The distance between the first nozzle 10-1 and the central axis of the fluidized bed 10 is r1, the distance between the second nozzle 10-2 and the central axis of the fluidized bed 10 is r2, and the radius of the riser with a large diameter section is R. Then 0.75 < r1 / R < 1, 0.5 < r2 / R < 0.75.

[0038] A first ash discharge opening 9-4 is formed on the upper air supplement chamber, and a cover body is installed on the first ash discharge opening 9-4. A second ash discharge opening 9-1 is formed on the lower air supplement chamber, and a cover body is installed on the second ash discharge opening 9-1. The purpose of setting the first ash discharge opening 9-4 and the second ash discharge opening 9-1 is to discharge the solid particles in the upper air supplement chamber and the lower air supplement chamber after an emergency occurs. During the air supplement process, the cover bodies on the first ash discharge opening 9-4 and the second ash discharge opening 9-1 are closed. When an abnormal situation occurs, the air supplement is stopped, and the cover bodies on the first ash discharge opening 9-4 and the second ash discharge opening 9-1 are opened for ash cleaning.

[0039] A plurality of protruding pyramids are formed on the inner wall of the reduced-diameter section. Preferably, the pyramid is a triangular pyramid. The included angle between the uppermost inclined plane of each pyramid and the inner wall of the reduced-diameter section where the pyramid is located is 5 to θ°.

[0040] The included angle θ between the inclined plane of the reduced-diameter section and the horizontal plane is 40 to 89°.

[0041] The height of the upper air supplement chamber is 0.25 to 1 m, and the height of the lower air supplement chamber is 0.25 to 1 m.

[0042] The height of the first outlet of the companion bed 11 is higher than the height of the small-diameter section riser 6, so that the catalyst discharged from the first outlet can re-enter the fluidized bed under the action of gravity.

[0043] Embodiment 3

[0044] On the basis of Embodiment 2, the eighth pipeline 23 is composed of two branch pipelines, and a second gas flowmeter and a second valve are installed on each branch pipeline. One branch pipeline is connected to each of the first air supplement inlet 9-3 and the second air supplement inlet 9-2. The flow rates of the 2 branch pipelines can be regulated separately.

[0045] A pressure sensor 7 is provided on the fluidized bed 10, a temperature sensor is provided on the fluidized bed 10, a catalyst concentration sensor is provided on the fluidized bed 10, and a velocity sensor is provided on the fluidized bed 10. The velocity sensor is used to detect the velocity of the catalyst. The pressure sensor 7, the temperature sensor, the catalyst concentration sensor, and the velocity sensor are all electrically connected to the computer 8.

[0046] The exhaust ports of the first cyclone separator 12 and the second cyclone separator 13 are communicated with an absorption device 14, and the absorption device 14 is used for absorbing the harmful gases and part of the catalyst discharged from the exhaust ports of the first cyclone separator 12 and the second cyclone separator 13. The absorption device 14 communicates with the outside through a seventh pipeline 25 and is used for discharging the gases after removing the harmful gases and part of the catalyst. The absorption device 14 is filled with a modified fiber material to achieve the absorption of the harmful gases and part of the catalyst, thereby improving the environment. For example, the modified fiber material can adopt the renewable fiber balls in the application No. 2018113390028.

[0047] The gas distributor 5 is arranged at the bottom of the riser 6 in the small-diameter section of the fluidized bed 10.

[0048] The ash discharge port of the second cyclone separator 13 is communicated with the riser 6 in the small-diameter section of the fluidized bed 10 through a fifth pipeline 17.

[0049] A first gas flowmeter 4 and a first valve 22 are arranged on the second pipeline 16.

[0050] The vent port of the buffer tank 2 is communicated with the absorption device 14 through a sixth pipeline 21, and a vent valve 3 is arranged on the sixth pipeline 21. Before starting the novel combined small-diameter-section riser fluidized bed reaction device of the present invention, the vent valve 3 should be opened to avoid excessive pressure in the buffer tank; when the novel combined small-diameter-section riser fluidized bed reaction device is operating, the vent valve 3 is adjusted (when the first valve 22 and the second valve adjust a large gas flow rate, the vent valve 3 is closed; when the first valve 22 and the second valve adjust a small gas flow rate, the vent valve 3 is opened to avoid excessive pressure in the buffer tank), and through cooperation with the first valve 22 on the second pipeline 16, the gas-solid flow in the fluidized bed reaches a specific flow pattern; before stopping the novel combined small-diameter-section riser fluidized bed reaction device, the vent valve 3 is opened again.

[0051] The above makes an exemplary description of the present invention. It should be noted that without departing from the core of the present invention, any simple deformation, modification or equivalent substitution that can be made by those skilled in the art without creative labor falls within the protection scope of the present invention.

Claims

1. An air supplement device for a fluidized bed, characterized in that, Including: An upper air supplement chamber and a lower air supplement chamber. Both the upper air supplement chamber and the lower air supplement chamber are annular cavities and are sleeved outside the fluidized bed (10). The fluidized bed (10) successively includes a large-diameter section riser, a variable-diameter section, and a small-diameter section riser (6) from top to bottom. The upper air supplement chamber is sleeved on the lower part of the large-diameter section riser, and the upper part of the variable-diameter section is located inside the upper air supplement chamber. The lower air supplement chamber is sleeved on the upper part of the small-diameter section riser (6), and the lower part of the variable-diameter section is located inside the lower air supplement chamber. A first air supplement inlet (9-3) is formed on the upper air supplement chamber, and a second air supplement inlet (9-2) is formed on the lower air supplement chamber. A plurality of first nozzles (10-1) are arranged on the fluidized bed (10) inside the upper air supplement chamber, and a plurality of second nozzles (10-2) are arranged on the fluidized bed (10) inside the lower air supplement chamber. Both the first nozzles (10-1) and the second nozzles (10-2) are located in the variable-diameter section; A plurality of protruding pyramids are formed on the inner wall of the variable-diameter section; The included angle between the uppermost inclined plane of each pyramid and the inner wall of the variable-diameter section where the pyramid is located is 5 to θ°; The distance between the first nozzle (10-1) and the central axis of the fluidized bed (10) is r1, the distance between the second nozzle (10-2) and the central axis of the fluidized bed (10) is r2, and the radius of the large-diameter section riser is R. Then 0.75 < r1 / R < 1, 0.5 < r2 / R < 0.75; Under the action of the air supplement device, a negative pressure area is formed in the upper part of the small-diameter section riser (6), which improves the pulling effect of the gas-solid fluid in the lower part of the small-diameter section riser (6), thereby suppressing the occurrence of plugging phenomena in the lower part of the small-diameter section riser (6), and enabling the gas-solid flow characteristics in the lower part of the small-diameter section riser to obtain a higher particle concentration and a uniform axial-radial flow effect; Under the action of the air supplement device, the upper part of the large-diameter section riser provides a lifting effect for the gas-solid fluid in the upper part of the large-diameter section riser, accelerates the transportation of the gas-solid fluid, and reduces the gas-solid backmixing in the side wall area of the upper part of the large-diameter section riser; The setting of the air supplement device enables flexible control of the large-diameter section riser and the small-diameter section riser respectively, thereby reducing the probability of side reactions and over-reactions occurring in the large-diameter section riser and the small-diameter section riser.

2. The air supplement device according to claim 1, characterized in that, A first air supplement chamber ash discharge port (9-4) is formed on the upper air supplement chamber, and a cover is installed on the first air supplement chamber ash discharge port (9-4).

3. The air supplementing device according to claim 2, wherein, A second air supplement chamber ash discharge port (9-1) is formed on the lower air supplement chamber, and a cover is installed on the second air supplement chamber ash discharge port (9-1).

4. The air supplement device according to claim 1, characterized in that, The pyramid is a triangular pyramid.

5. The air supplement device according to claim 1, wherein The number of the first nozzles (10-1) is 4 to 12 and is arranged on the fluidized bed (10) along the circumferential direction, and the number of the second nozzles (10-2) is 4 to 12 and is arranged on the fluidized bed (10) along the circumferential direction.

6. The air supplement device according to claim 1, wherein The included angle θ between the inclined plane of the variable-diameter section and the horizontal plane is 40 to 89°.

7. The air supplement device according to claim 1, wherein The height of the upper air supplement chamber is 0.25 to 1 m, and the height of the lower air supplement chamber is 0.25 to 1 m.

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