Carbon dioxide capture apparatus for reducing the alkalinity of red mud

Abstract

This utility model relates to the field of industrial waste treatment technology, specifically a carbon dioxide capture device for reducing the alkalinity of red mud. It includes a reactor body with a central air inlet pipe vertically penetrating the bottom center. The top of the central air inlet pipe is connected to a double-layer annular distribution chamber via a rotary coupling joint. The double-layer annular distribution chamber is horizontally positioned in the lower part of the reactor body, and radial guide vanes are evenly distributed within its annular channel. The bottom outlet of the central air inlet pipe extends into a bottom annular pressure equalization chamber. A porous conical diffuser is fixedly installed below the bottom annular pressure equalization chamber. This carbon dioxide capture device for reducing the alkalinity of red mud enables more uniform distribution of flue gas in the red mud slurry, prolongs the gas residence time, and improves the reaction efficiency and capture rate of carbon dioxide with red mud.

Description

Technical Field

[0001] This utility model relates to the field of industrial waste treatment technology, specifically to a carbon dioxide capture device for reducing the alkalinity of red mud. Background Technology

[0002] The production of alumina generates a large amount of red mud, a highly alkaline waste that, if stored for a long time, easily pollutes soil and groundwater, making it difficult to treat. Meanwhile, the flue gas emitted during the combustion of industrial boilers contains a large amount of carbon dioxide, one of the major greenhouse gases. In recent years, the carbon dioxide in boiler flue gas has been used to react with red mud via a carbonation reaction, which can neutralize the alkalinity of the red mud and achieve carbon dioxide fixation and resource utilization.

[0003] Currently, common treatment devices introduce flue gas into the red mud slurry from the bottom of the reactor through a straight pipe or a perforated annular pipe. However, this gas distribution structure has significant shortcomings: the concentrated release of gas from the central area or a single annular zone easily creates localized airflow channels in the slurry, leading to gas short-circuiting and rapid upward escape. This results in insufficient contact time and contact area between the flue gas and the red mud, causing a large amount of carbon dioxide to be discharged from the system without participating in the reaction. Consequently, this not only results in low carbon dioxide capture efficiency but also affects the stability and thoroughness of red mud alkali reduction, leading to low overall reaction efficiency and limiting the large-scale application of this technology. Utility Model Content

[0004] The purpose of this invention is to provide a carbon dioxide capture device that reduces the alkalinity of red mud, so as to solve the problems mentioned in the background art, such as uneven distribution of flue gas in red mud slurry, easy formation of airflow channels, resulting in insufficient contact between gas and red mud, low reaction efficiency, and low carbon dioxide capture rate.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a carbon dioxide capture device for reducing the alkalinity of red mud, comprising a reactor body, a central air inlet pipe vertically penetrating the bottom center of the reactor body, a double-layer annular flow distribution cavity connected to the top of the central air inlet pipe via a rotary coupling joint, the double-layer annular flow distribution cavity being horizontally positioned in the lower middle part of the reactor body, and a radial guide vane array evenly distributed within the annular channel of the double-layer annular flow distribution cavity, the bottom outlet of the central air inlet pipe extending into the bottom annular pressure equalization cavity, and a porous conical diffuser fixedly installed below the bottom annular pressure equalization cavity.

[0006] Preferably, the double-layer annular diversion cavity is a concentric annular structure composed of an inner annular wall and an outer annular wall, and the height of the annular channel is 150mm to 250mm.

[0007] Preferably, the radial guide plate array includes 6 to 12 groups of guide units, each group consisting of 3 to 5 inclined metal plates with an angle of 20° to 30° between adjacent plates and an angle of 35° to 45° between the plates and the bottom surface of the annular channel. The surface of the plates is provided with a micro-dimple array structure.

[0008] Preferably, the bottom annular equalizing chamber is a cylindrical structure with an open bottom, its inner diameter is 4 times the diameter of the central air intake pipe, the height of the chamber is 1.5 to 2 times the diameter of the central air intake pipe, the outer periphery is provided with a downwardly extending closed skirt, the inner wall of the chamber is provided with an annular guide groove, and the connection between the bottom annular equalizing chamber and the porous conical diffuser is provided with an annular sealing gasket.

[0009] Preferably, the porous conical diffuser is in the shape of an inverted cone, with through holes of 5 mm to 8 mm in diameter evenly distributed on the side wall and the hole spacing is 15 mm to 20 mm. Guide ribs are wrapped around the outer conical surface of the porous conical diffuser, and support arms are symmetrically arranged on the outer ring wall of the double-layer annular diversion cavity. The end of the support arm is connected to the annular guide shroud.

[0010] Preferably, the rotary coupling joint includes an inner ring rotating body fixedly connected to the central intake pipe and an outer ring fixed body connected to the double-layer annular diversion cavity, with a sealed bearing provided between the inner ring rotating body and the outer ring fixed body.

[0011] Compared with existing technologies, the beneficial effects of this invention are as follows: This carbon dioxide capture device, which reduces the alkalinity of red mud, enables more uniform distribution of flue gas in the red mud slurry, prolongs the gas residence time, and improves the reaction efficiency and capture rate of carbon dioxide with red mud. Through the combined design of a bottom annular pressure equalization chamber and a porous conical diffuser, the device achieves initial uniform diffusion of gas at the bottom of the reactor. The combination of a double-layer annular flow distribution chamber and a radial guide vane array allows the gas to form a circumferential flow in the upper and middle parts, expanding the gas distribution range. Combined with the stable introduction of gas flow through a rotary coupling connector, the entire device forms a multi-stage synergistic gas distribution structure, effectively avoiding gas flow short-circuiting and localized concentrated escape, significantly improving the mass transfer efficiency and operational stability of the reaction system. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of a carbon dioxide capture device for reducing the alkalinity of red mud according to the present invention. Figure 2 This is a schematic diagram of the internal structure of the double-layer annular diversion cavity of a carbon dioxide capture device for reducing the alkalinity of red mud according to this utility model. Figure 3 This is a schematic diagram of the external structure of the carbon dioxide capture device for reducing the alkalinity of red mud according to this utility model, showing the connection between the double-layer annular diversion cavity and the porous conical diffuser.

[0013] In the figure: 1. Reactor body; 2. Central air inlet pipe; 3. Double-layer annular flow distribution chamber; 4. Radial guide vane array; 5. Bottom annular pressure equalization chamber; 6. Porous conical diffuser; 7. Rotary coupling joint; 8. Annular sealing gasket; 9. Flow guide ribs; 10. Support arm; 11. Annular flow guide hood. Detailed Implementation

[0014] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0015] Please see Figure 1-3This utility model provides a technical solution: a carbon dioxide capture device for reducing the alkalinity of red mud, including a reactor body 1. A central air inlet pipe 2 is vertically installed through the center of the bottom of the reactor body 1. A double-layer annular diversion cavity 3 is connected to the central air inlet pipe 2 through a rotary coupling joint 7. The central air inlet pipe 2 and the inner ring rotating body of the rotary coupling joint 7 are connected by threads and fixed with a locking nut to ensure airtightness. The outer ring wall of the double-layer annular diversion cavity 3 is connected to the outer ring fixing body of the rotary coupling joint 7 through a flange and fastened with high-strength bolts to achieve stable support and sealing. The double-layer annular diversion cavity 3 is horizontally arranged in the lower part of the reactor body 1, and a radial guide vane array 4 is evenly distributed in the annular channel of the double-layer annular diversion cavity 3. The plate array 4 is formed by stamping stainless steel sheet. Each guide plate is fixed between the inner and outer ring walls of the double-layer annular diversion cavity 3 by spot welding, and is arranged radially and obliquely. The bottom outlet of the central air inlet pipe 2 extends into the bottom annular pressure equalization cavity 5. A porous conical diffuser 6 is fixedly installed below the bottom annular pressure equalization cavity 5. The porous conical diffuser 6 and the bottom annular pressure equalization cavity 5 are connected by an annular flange. An annular sealing gasket 8 is sandwiched between them and locked with circumferentially distributed clamps to ensure a firm connection and easy disassembly and maintenance. With this structure, when the flue gas enters the bottom of the reactor body 1 through the central air inlet pipe 2, the airflow is initially evenly distributed in the bottom annular pressure equalization cavity 5, effectively avoiding concentrated gas injection. Then the gas rises into the porous conical diffuser 6, making... The airflow enters the bottom layer of the red mud slurry in a fine form. Simultaneously, the gas at the top of the central air inlet pipe 2 is introduced into the double-layer annular distribution cavity 3 via the rotary coupling joint 7. Guided by the radial guide vane array 4, it forms a circumferential flow along the annular channel, allowing the gas to be evenly released from the annular area of ​​the double-layer annular distribution cavity 3. This forms a three-dimensional gas distribution pattern with the airflow rising from the bottom porous conical diffuser 6, which works in conjunction with the airflow from above and below and is linked from inside and outside. This greatly increases the gas distribution area and residence time in the slurry, significantly improving the contact frequency and reaction sufficiency of carbon dioxide with red mud particles. This effectively solves the problems of airflow short-circuiting, local escape, and uneven contact caused by the concentrated release of gas from the center or a single annular zone in the existing technology, thus improving the carbon dioxide capture efficiency and the red mud alkali reduction reaction. To ensure stability and thoroughness, the double-layer annular flow distribution cavity 3 is a concentric annular structure composed of an inner and outer annular walls, with an annular channel height of 150mm to 250mm. This structure allows the double-layer annular flow distribution cavity 3 to form a large annular gas distribution area inside the reactor body 1. When the gas flows in the channel between the inner and outer annular walls, it is effectively expanded to a wide annular space close to the reactor wall, significantly increasing the coverage area for gas release. At the same time, the channel height provides sufficient rectification space for the gas flow, making the gas distribution more uniform and the flow rate more stable before entering the red mud slurry, thereby improving the overall reaction efficiency. The radial guide plate array 4 contains 6 to 12 groups of guide units, each group consisting of 3 to 5 inclined metal plates with an angle of 20° to 30° between adjacent plates.The plate forms an angle of 35° to 45° with the bottom surface of the annular channel. The plate surface has a micro-dimple array structure. When gas flows through the annular channel of the double-layer annular diversion cavity 3, the radial guide plate array 4 cuts and guides the airflow at multiple points, promoting turbulence and enhancing the mixing with the red mud slurry. Simultaneously, the micro-dimple array on the plate surface can induce local eddies, further strengthening the gas-liquid interface disturbance and improving the mass transfer rate and reaction sufficiency of carbon dioxide. The bottom annular equalizing cavity 5 is a cylindrical structure with an open bottom. Its inner diameter is four times the diameter of the central inlet pipe 2, and its height is 1.5 to 2 times the diameter of the central inlet pipe 2. It has a downward-extending closed skirt on its outer periphery, and annular guide grooves on the inner wall of the cavity. The bottom annular equalizing cavity 5 and the porous conical diffuser hood... An annular sealing gasket 8 is provided at the connection of 6. This structure utilizes the expanded diameter design of the bottom annular equalizing chamber 5 to rapidly diffuse and reduce the velocity of the high-speed airflow ejected from the central air inlet pipe 2, achieving initial uniform distribution of airflow. The closed skirt and the annular guide groove work together to guide the gas to flow circumferentially along the cavity, avoiding local eddies or short circuits. At the same time, the annular sealing gasket 8 ensures a sealed connection between the cavity and the porous conical diffuser 6, preventing gas leakage. This ensures that all flue gas is released in an orderly manner from the through holes of the hood after equalization, guaranteeing gas distribution stability and reaction continuity. The porous conical diffuser 6 is an inverted cone shape, with through holes of 5mm to 8mm in diameter evenly distributed on the side wall, with a hole spacing of 15mm to 20mm. A guide is wound around the outer conical surface of the porous conical diffuser 6. The flow ribs 9 and the outer ring wall of the double-layer annular flow distribution cavity 3 are symmetrically provided with support arms 10. The end of the support arm 10 is connected to an annular flow guide shroud 11. The support arm 10 is an L-shaped steel component. One end is fixed to the outer ring wall of the double-layer annular flow distribution cavity 3 by welding, and the other end extends horizontally and is bolted to the outer ring of the annular flow guide shroud 11. The annular flow guide shroud 11 is an annular shell with an inverted U-shaped cross section. Its top opening is slightly smaller than the inner diameter of the reactor body 1. The lower edge of the shroud is 50-80mm away from the upper surface of the double-layer annular flow distribution cavity 3. It is used to constrain the rising airflow and prevent bubbles from merging and rising too quickly. This structure uses a porous conical diffuser shroud 6 to evenly disperse the gas entering from the bottom into fine airflow, which diffuses upward from the lower slurry area, avoiding concentrated airflow impact and guiding the flow. Ribs 9 guide the slurry to form an upward flow along the wall, reducing particle deposition. Simultaneously, the support arm 10 and the annular guide shroud 11 form an annular guide zone in the upper part of the reactor, which, in conjunction with the double-layer annular flow divider 3, makes the upper airflow distribution more uniform, suppressing liquid surface disturbance and bubble merging and escape. Overall, this achieves a continuous and stable gas-liquid distribution from the bottom to the upper middle, improving reaction efficiency. The rotary coupling joint 7 includes an inner rotating body fixedly connected to the central air inlet pipe 2 and an outer fixed body connected to the double-layer annular flow divider 3. A sealed bearing is provided between the inner rotating body and the outer fixed body. The sealed bearing is a double-row angular contact ball bearing with built-in grease and a dustproof seal ring, allowing stable operation within a ±5° deflection range, accommodating minor displacements caused by thermal expansion within the reactor.This structure allows the double-layered annular distribution chamber 3 to maintain a stable orientation under external stirring or fluid impact, while the central inlet pipe 2 can rotate or be fixed independently. Sealed bearings ensure reliable gas transmission even when the relative positions of the inner and outer rings change, preventing interface leakage due to vibration or thermal deformation, ensuring long-term stable operation of the gas path, and improving the overall reliability of the device.

[0016] Working principle: When using this carbon dioxide capture device to reduce the alkalinity of red mud, the boiler exhaust gas is first introduced into the central inlet pipe 2 through a pipeline. The gas flows downward along the central inlet pipe 2 to the bottom annular equalization chamber 5, and then enters the porous conical diffuser 6 and is released upward through the through holes in its side wall into the bottom layer of red mud slurry in the reactor body 1. At the same time, another stream of gas enters the double-layer annular diversion chamber 3 from the central inlet pipe 2 through the rotary coupling joint 7. Under the action of the radial guide vane array 4, the gas is distributed along the annular channel and flows out from the circumference of the double-layer annular diversion chamber 3. The gas is released into the lower middle slurry zone. During the ascent, the gas comes into full contact with the red mud and undergoes a carbonation reaction. The exhaust gas after the reaction is discharged from the upper part of the reactor body 1. During this period, the annular sealing gasket 8 between the bottom annular equalizing chamber 5 and the porous conical diffuser 6 remains sealed. The annular guide shroud 11 connected to the support arm 10 maintains the stability of the flow field in the upper middle part. The guide ribs 9 are arranged along the outer conical surface of the porous conical diffuser 6. The inner ring rotating body and the outer ring fixed body in the rotary coupling joint 7 achieve relative position stability and smooth airflow through the sealed bearing, thereby completing a series of operations.

[0017] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A carbon dioxide capture device for reducing the alkalinity of red mud, comprising a reaction vessel body (1), characterized in that: A central air inlet pipe (2) is vertically installed through the bottom center of the reactor body (1). A double-layer annular flow divider (3) is connected to the central air inlet pipe (2) through a rotary coupling joint (7). The double-layer annular flow divider (3) is horizontally installed in the lower part of the reactor body (1). A radial guide vane array (4) is evenly distributed in the annular channel of the double-layer annular flow divider (3). The bottom outlet of the central air inlet pipe (2) extends into the bottom annular pressure equalization chamber (5). A porous conical diffuser hood (6) is fixedly installed below the bottom annular pressure equalization chamber (5).

2. The carbon dioxide capture device for reducing the alkalinity of red mud according to claim 1, characterized in that: The double-layer annular diversion cavity (3) is a concentric annular structure composed of an inner annular wall and an outer annular wall, with an annular channel height of 150mm to 250mm.

3. The carbon dioxide capture device for reducing the alkalinity of red mud according to claim 1, characterized in that: The radial guide plate array (4) includes 6 to 12 groups of guide units, each group consisting of 3 to 5 inclined metal plates with an angle of 20° to 30° between adjacent plates and an angle of 35° to 45° between the plates and the bottom surface of the annular channel. The surface of the plates is provided with a micro-dimple array structure.

4. A carbon dioxide capture device for reducing the alkalinity of red mud according to claim 1, characterized in that: The bottom annular equalizing chamber (5) is a cylindrical structure with an open bottom. Its inner diameter is 4 times the diameter of the central air inlet pipe (2), and the height of the chamber is 1.5 to 2 times the diameter of the central air inlet pipe (2). It has a closed skirt extending downward around its outer periphery, and an annular guide groove is provided on the inner wall of the chamber. An annular sealing gasket (8) is provided at the connection between the bottom annular equalizing chamber (5) and the porous conical diffuser (6).

5. A carbon dioxide capture device for reducing the alkalinity of red mud according to claim 1, characterized in that: The porous conical diffuser (6) is an inverted cone shape, with through holes of 5 mm to 8 mm in diameter evenly opened on the side wall and the hole spacing is 15 mm to 20 mm. The outer conical surface of the porous conical diffuser (6) is surrounded by flow guide ribs (9), and the outer ring wall of the double-layer annular flow divider (3) is symmetrically provided with support arms (10), and the end of the support arm (10) is connected to an annular flow guide (11).

6. A carbon dioxide capture device for reducing the alkalinity of red mud according to claim 1, characterized in that: The rotary coupling joint (7) includes an inner ring rotating body fixedly connected to the central air intake pipe (2) and an outer ring fixed body connected to the double-layer annular diversion cavity (3), with a sealed bearing provided between the inner ring rotating body and the outer ring fixed body.

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