Method and apparatus for recovering waste heat from calcination of alumina

Abstract

The application discloses a kind of production alumina calcination waste heat recovery method and equipment, it is related to alumina calcination technical field, including by intake volute, outer tube, cone tube, discharge port, gas inner tube component of cyclone cylinder assembly, anti-blocking disturbance component, the anti-blocking disturbance component is used to disturb the material inside cone tube, to this realizes the effect of avoiding the material inside cone tube congealing.The application is provided with anti-blocking disturbance component, so that external high-pressure pulse gas enters gas warehouse, then uniformly permeates through gas-permeable wear-resistant microporous lining, forms a layer of very thin "air cushion" on the inner wall surface of gas-permeable wear-resistant microporous lining, so that the material close to the inner wall of cone tube is disturbed, so as to eliminate the congealing phenomenon of material, while avoiding the adhesion of material and inner wall of cone tube, at the same time, the micron-level pores that are through and uniform in the gas-permeable wear-resistant microporous lining inside can make gas permeate out, but solid particles are difficult to enter, which fundamentally avoids the pore blockage problem of gas-permeable wear-resistant microporous lining.

Description

Technical Field

[0001] This invention relates to the field of alumina roasting technology, specifically a method and equipment for recovering waste heat from alumina roasting. Background Technology

[0002] Alumina gaseous suspension roasting is currently the mainstream process in the industry. One of its core energy-saving measures is the recovery of waste heat from the high-temperature flue gas in the roasting furnace through a multi-stage cyclone preheater. The multi-stage cyclone preheater consists of multiple cyclone components connected in series. It utilizes the high-temperature flue gas generated during roasting to directly exchange heat with the room-temperature alumina material through counter-current contact within the multi-stage cyclones. This preheats the material to approximately 900°C before it enters the roasting furnace, significantly reducing fuel consumption. Its working principle is as follows: high-temperature flue gas flows upward through each cyclone, while the material falls downward under the negative pressure of the system. After heat exchange in the connecting pipes of each cyclone stage, the cyclones use centrifugal force to separate the preheated material from the cooled flue gas. The separated material enters the next stage to continue absorbing heat, while the separated flue gas enters the previous stage to continue releasing heat. This stage-by-stage heat exchange ultimately achieves the cascade recovery and utilization of waste heat.

[0003] However, in actual production, the conical section of the cyclone preheater is prone to blockage, severely affecting the stable operation of the waste heat recovery system and equipment uptime. Existing research indicates that blockage in the cyclone preheater system and its connecting structures is one of the main reasons for the forced shutdown of the alumina roasting system. The causes of blockage mainly include the following two aspects: First, when the water content of aluminum hydroxide is too high, the material enters the cyclone before it has sufficient time to dry in the preheater, forming wet mud-like agglomerates in the conical section that adhere to the wall, accumulating thicker and thicker until the outlet is blocked; Second, when fine aluminum hydroxide powder accumulates at the bottom of the cone, the van der Waals forces between the fine powder particles are significantly enhanced, the internal friction angle of the material increases, and the fluidity deteriorates, forming an arch bridge structure above the cone outlet, causing obstruction of material flow. Once blockage occurs, the machine must be shut down for cooling and manual cleaning, which not only directly interrupts production but also wastes a large amount of recovered waste heat due to the disruption of the system's thermal balance. Restarting requires additional energy consumption, severely reducing the overall efficiency of alumina roasting.

[0004] To address the problem of cyclone cone blockage, existing technologies include methods to improve material flow by modifying the structural design of the cyclone and connecting pipes, or extending the cyclone's service life by using wear-resistant linings. However, these solutions are all passive protection or structural improvements and fail to fundamentally solve the problem of material adhesion and accumulation on the cone wall. Therefore, there is an urgent need for a device that can actively intervene in the material flow state of the cone online, preventing material caking and wall adhesion, to ensure the long-term stable operation of multi-stage cyclone preheater systems. Summary of the Invention

[0005] The purpose of this invention is to provide a method and equipment for recovering waste heat from the roasting of alumina in order to solve the problems mentioned above.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for recovering waste heat from alumina roasting, the specific steps of which are as follows: Step 1: Place the aluminum hydroxide raw material at room temperature into a Venturi dryer to complete the pre-drying treatment; Step 2: The material dried by the Venturi dryer is sent into the cyclone preheater system. Under the negative pressure of the system, the material flows from top to bottom through the first-stage cyclone preheater, the second-stage cyclone preheater, the third-stage cyclone preheater, ..., the Nth-stage cyclone preheater in the cyclone preheater system, and exchanges heat with the high-temperature flue gas rising from the roasting furnace in a counter-current manner. Step 3: In each stage of the cyclone preheater, the flue gas flows upward and the material sinks downward. The material is continuously heated by the flue gas, and the flue gas is continuously cooled by the material. After each stage completes the gas-solid heat exchange, the preheated material and the cooled flue gas are separated by the centrifugal force of the cyclone preheater: the separated material enters the next stage of the cyclone preheater to continue absorbing heat, and the separated flue gas enters the previous stage of the cyclone preheater to continue releasing heat. Step 4: The material, which has been preheated to the set temperature through multiple stages of the Nth stage cyclone preheater, is discharged from the bottom of the cyclone preheater system and directly sent into the calcining furnace for high-temperature calcination. After calcination, alumina product is produced. Step 5: The low-temperature flue gas discharged from the first-stage cyclone preheater is led out to the purification system and discharged after purification treatment to meet the standards.

[0007] A waste heat recovery device for alumina roasting includes the cyclone preheater system described in step two. The cyclone preheater system includes at least three stages of cyclone preheaters. The cyclone preheater includes a cyclone cylinder assembly consisting of an inlet volute, an outer cylinder, a cone, a discharge port, and an outlet inner cylinder. The inlet volute, outer cylinder, and cone are connected and communicated sequentially from top to bottom. The discharge port is fixed to the bottom of the cone and is connected to the cone, providing a channel for the heated and separated material to enter the next stage; The exhaust inner cylinder is fixed to the top of the intake volute and extends downward into the outer cylinder, providing a channel for the separated flue gas to enter the next stage. An anti-clogging disturbance component is provided on the outside of the cone. The anti-clogging disturbance component is used to disturb the material inside the cone, thereby preventing the material inside the cone from caking. The anti-clogging disturbance component includes an airflow disturbance unit and a disassembly / assembly unit; The airflow disturbance unit disturbs the material inside the cone by using external high-pressure pulsed gas. The disassembly and assembly unit is used to provide support and guidance for the disassembly and maintenance of the airflow disturbance unit.

[0008] As a further embodiment of the present invention: the airflow disturbance unit includes a conical ring cover, a side-tilted T-shaped compartment, a sealing plate, an air inlet, and a breathable and wear-resistant microporous lining; The conical ring cover is fixed to the outside of the conical cylinder, and the side-inverted T-shaped compartment is opened inside the conical ring cover and penetrates the inner and outer walls of the conical ring cover. A through slot is opened on the inner side of the conical cylinder at a position aligned with the side-inverted T-shaped compartment, and the through slot is connected to the side-inverted T-shaped compartment. The breathable and wear-resistant microporous lining is installed inside the side-inverted T-shaped compartment and extends into the inside of the through slot. The sealing plate is installed on the outside of the conical ring cover and forms a seal against the side-inverted T-shaped compartment opening; The interior of the side-tilted T-shaped chamber is formed between the sealing plate and the breathable and wear-resistant microporous lining to form an air chamber. The air inlet is fixed to the outside of the sealing plate and passes through the sealing plate to communicate with the air chamber. The air inlet is used to connect with an external air source. External high-pressure pulsed gas enters the gas chamber through the air inlet, and then evenly passes through the breathable and wear-resistant microporous lining into the inside of the cone to achieve the effect of disturbing the material inside the cone.

[0009] As a further embodiment of the present invention: the breathable and wear-resistant microporous lining is composed of a side-inverted T-shaped inner lining block, a vertical protrusion, and a horizontal reinforcing rib. The vertical protrusion and the horizontal reinforcing rib are integrally formed from the horizontal reinforcing rib, and the vertical protrusion and the horizontal reinforcing rib are perpendicular to each other. The side-inverted T-shaped inner lining block, vertical protrusion, and horizontal reinforcing rib are integrally formed by adding a pore-forming agent and a molding process.

[0010] As a further embodiment of the present invention: a bottom support plate is fixed to the inner bottom of the sealing plate, and two limiting brackets are symmetrically fixed to the upper surface of the bottom support plate; The bottom of the side-inverted T-shaped inner liner block is attached to the upper surface of the sealing plate, and the vertical protrusion is inserted into the inner side of the limiting card seat to realize the composition of the breathable and wear-resistant microporous liner and the sealing plate.

[0011] As a further embodiment of the present invention: high-temperature resistant sealing elements are provided at the contact positions between the inner side of the side-inverted T-shaped compartment and the inner lining block and the bottom support plate, and a pressure detection port communicating with the air chamber is fixed on the outer side of the sealing plate.

[0012] As a further embodiment of the present invention: the disassembly and assembly unit includes a fixed guide rod and a limiting circular block; The fixed guide rod is symmetrically fixed to the outside of the conical ring cover with the center line of the side-inverted T-shaped compartment as the center and passes through the sealing plate. The sealing plate has a sleeve hole that matches the outer wall of the fixed guide rod. The limiting block is fixed to the side of the fixed guide rod away from the conical ring cover, and is used to limit the outward movement of the sealing plate.

[0013] As a further aspect of the present invention: multiple conical ring covers are evenly arranged along the vertical trajectory of the cone cylinder, and multiple side-inverted T-shaped compartments are arranged in a ring on a single conical ring cover. The number and position of the through slots inside the cone cylinder correspond one-to-one with the number and position of the side-inverted T-shaped compartments.

[0014] As a further embodiment of the present invention: two vertically adjacent through slots are staggered along the circumferential direction, and the inner wall surface of the side-inverted T-shaped inner liner block is flush with the inner wall surface of the cone.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention involves installing an anti-clogging disturbance component on the outside of a cyclone cone, forming an air chamber structure on the cone wall composed of a side-inverted T-shaped chamber and a sealing plate. A breathable, wear-resistant microporous liner is embedded within the side-inverted T-shaped chamber. High-pressure pulsed gas enters the air chamber through the inlet and then evenly permeates through the breathable, wear-resistant microporous liner into the cone, forming an extremely thin air cushion on the inner wall surface of the liner. This air cushion continuously agitates the material near the cone wall, effectively eliminating material caking and accumulation at the bottom of the cone, while preventing wet material from adhering to the inner wall of the cone, thus preventing outlet blockage caused by material caking at the source.

[0016] 2. The breathable and wear-resistant microporous lining of the present invention has through and uniform micron-sized pores inside. Gas can permeate out under pulse pressure, while solid material particles, because their particle size is much larger than the micropore diameter, have difficulty entering the micropores. This fundamentally avoids the problem of conventional gas purging devices losing function due to pore blockage, ensures the long-term stable operation of the anti-clogging disturbance component, and extends the equipment maintenance cycle.

[0017] 3. By setting up a breathable and wear-resistant microporous lining structure integrally formed by a side-inverted T-shaped inner lining block, a vertical protrusion and a transverse reinforcing rib, the present invention can significantly improve the structural strength and wear resistance of the lining while ensuring uniform air permeability. It can withstand the high temperature and high wear conditions inside the cone during the alumina calcination process and extend the service life of the breathable and wear-resistant microporous lining.

[0018] 4. This invention, by setting up a disassembly and assembly unit consisting of a fixed guide rod and a limiting circular block, allows the sealing plate to move horizontally along the trajectory of the fixed guide rod, driving the breathable and wear-resistant microporous liner to move out or be pushed into the side-tilting T-shaped compartment simultaneously. The replacement and maintenance of the breathable and wear-resistant microporous liner can be completed quickly without disassembling the conical ring cover, which greatly reduces the difficulty of equipment maintenance and downtime.

[0019] 5. The present invention provides a method for recovering waste heat from alumina roasting. By installing the aforementioned anti-clogging disturbance components on the cones of each stage of the cyclone preheater system, high-pressure pulsed gas can be periodically injected into the inner wall of the cone during the roasting process, thereby achieving online disturbance of the material inside the cone. This disturbance operation can be completed without stopping the machine, without affecting the normal gas-solid separation and waste heat recovery process of each stage of the cyclone. It synergistically ensures the long-term stable operation of the multi-stage cyclone preheater system from both the equipment structure and operation method levels, reduces the number of production interruptions caused by cone blockage, and improves the overall operating rate and energy utilization efficiency of the alumina roasting waste heat recovery system. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a structural distribution diagram of the anti-clogging disturbance component and the cone of the present invention; Figure 3 This is another perspective view of the anti-clogging disturbance component and the cone of the present invention; Figure 4 This is a schematic diagram showing the state of the breathable and wear-resistant microporous liner of the present invention being removed from the side-tilted T-shaped compartment; Figure 5 This is a schematic diagram of the assembly of the breathable and wear-resistant microporous liner and the sealing plate of the present invention; Figure 6 This is a schematic diagram showing the disassembly of the breathable and wear-resistant microporous liner and the sealing plate of the present invention; Figure 7 This is another perspective view showing the separation of the breathable and wear-resistant microporous lining and the sealing plate of the present invention.

[0021] In the diagram: 1. Cyclone assembly; 101. Inlet volute; 102. Outer cylinder; 103. Conical cylinder; 104. Discharge port; 105. Inner outlet cylinder; 106. Through slot; 2. Anti-clogging and disturbance assembly; 201. Conical ring cover; 202. Side-tilting T-shaped chamber; 203. Sealing plate; 204. Inlet; 205. Pressure detection port; 206. Bottom support plate; 207. Limiting bracket; 208. Breathable and wear-resistant microporous lining; 209. Fixed guide rod; 210. Limiting block; 2081. Side-tilted T-shaped inner lining block; 2082. Vertical protrusion; 2083. Horizontal reinforcing rib. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. In the description of this invention, it should be noted that unless otherwise explicitly specified and limited, the terms "installed," "connected," "linked," and "set up" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. The following describes embodiments of the invention based on its overall structure.

[0024] Please see Figures 1 to 7 In this embodiment of the invention, a method for recovering waste heat from alumina roasting includes the following specific steps: Step 1: Place the aluminum hydroxide raw material at room temperature into a Venturi dryer to complete the pre-drying treatment; Step 2: The material dried by the Venturi dryer is sent into the cyclone preheater system. Under the negative pressure of the system, the material flows from top to bottom through the first-stage cyclone preheater, the second-stage cyclone preheater, the third-stage cyclone preheater, ..., the Nth-stage cyclone preheater, where N is an integer greater than 3. It exchanges heat with the high-temperature flue gas rising from the roasting furnace in a counter-current manner. Step 3: In each stage of the cyclone preheater, the flue gas flows upward and the material sinks downward. The material is continuously heated by the flue gas, and the flue gas is continuously cooled by the material. After each stage completes the gas-solid heat exchange, the preheated material and the cooled flue gas are separated by the centrifugal force of the cyclone preheater: the separated material enters the next stage of the cyclone preheater to continue absorbing heat, and the separated flue gas enters the previous stage of the cyclone preheater to continue releasing heat. Step 4: The material, which has been preheated to the set temperature through multiple stages of the Nth stage cyclone preheater, is discharged from the bottom of the cyclone preheater system and directly sent into the calcining furnace for high-temperature calcination. After calcination, alumina product is produced. Step 5: The low-temperature flue gas discharged from the first-stage cyclone preheater is led out to the purification system and discharged after purification treatment to meet the standards.

[0025] A waste heat recovery device for alumina roasting includes the cyclone preheater system described in step two. The cyclone preheater system includes at least three stages of cyclone preheaters. The cyclone preheater includes a cyclone assembly 1 consisting of an inlet volute 101, an outer cylinder 102, a cone 103, a discharge port 104, and an outlet inner cylinder 105. The inlet volute 101, outer cylinder 102, and cone 103 are connected and communicate with each other from top to bottom. The discharge port 104 is fixed to the bottom of the cone 103 and communicates with the cone 103, providing a channel for the heated and separated material to enter the next stage. The outlet inner cylinder 105 is fixed to the top of the inlet volute 101 and extends downward into the outer cylinder 102, providing a channel for the separated flue gas to enter the previous stage. An anti-clogging disturbance component 2 is provided on the outside of the cone 103. The anti-clogging disturbance component 2 is used to disturb the material inside the cone 103, thereby preventing the material inside the cone 103 from caking.

[0026] The anti-clogging disturbance component 2 includes an airflow disturbance unit and a disassembly unit; the airflow disturbance unit disturbs the material inside the cone 103 by using external high-pressure pulsed gas; the disassembly unit provides support and guidance for the disassembly and maintenance of the airflow disturbance unit.

[0027] The airflow disturbance unit includes a conical annular cover 201, a side-tilting T-shaped chamber 202, a sealing plate 203, an air inlet 204, and a breathable and wear-resistant microporous lining 208. The conical annular cover 201 is fixed to the outside of the conical cylinder 103. The side-tilting T-shaped chamber 202 is opened inside the conical annular cover 201 and penetrates the inner and outer walls of the conical annular cover 201. A through slot 106 is opened on the inner side of the conical cylinder 103 at a position aligned with the side-tilting T-shaped chamber 202, and the through slot 106 is connected and conductive to the side-tilting T-shaped chamber 202. A wear-resistant microporous liner 208 is installed inside the side-inverted T-shaped chamber 202 and extends into the inside of the through slot 106; a sealing plate 203 is installed on the outside of the conical ring cover 201 and seals the opening of the side-inverted T-shaped chamber 202; an air chamber is formed inside the side-inverted T-shaped chamber 202 between the sealing plate 203 and the breathable wear-resistant microporous liner 208, and an air inlet 204 is fixed to the outside of the sealing plate 203 and passes through the sealing plate 203 to communicate with the air chamber, and the air inlet 204 is used to connect with an external air source. External high-pressure pulsed gas enters the air chamber through the air inlet 204, and then evenly passes through the breathable wear-resistant microporous liner 208 into the interior of the cone 103, in order to achieve the effect of disturbing the material inside the cone 103.

[0028] In this embodiment, it should be noted that multiple cyclone assemblies 1 are connected by corresponding pipes to form a multi-stage cyclone. The connection pipe structure is the same as that of a traditional multi-stage cyclone, so it will not be described in detail here. During the production of alumina, high-temperature flue gas and materials enter the outer cylinder 102 through the inlet volute 101. The preheated materials inside the outer cylinder 102 are separated from the flue gas under centrifugal force. The separated flue gas passes through the outlet inner cylinder 105 to the next stage to continue releasing heat, while the separated materials fall downward into the cone 103 and enter the next stage through the pipe connected to the discharge port 104 to continue absorbing heat.

[0029] During this process, the material accumulated at the bottom of the cone 103 is prone to blockage due to caking. At this time, the air inlet 204 can be connected to the external air source at regular intervals, so that the external high-pressure pulse gas (such as nitrogen) enters the air chamber through the air inlet 204 and then evenly passes through the breathable and wear-resistant microporous lining 208 (the breathable and wear-resistant microporous lining 208 has through and uniform micron-level air pores inside, similar to a ceramic filter). A very thin "air cushion" is formed on the inner wall surface of the breathable and wear-resistant microporous lining 208. Through short-term blowing of 3-5 seconds, the material near the inner wall of the cone 103 is disturbed, thus eliminating the caking phenomenon and preventing the material from sticking to the inner wall of the cone 103. After repeating this blowing process several times, the air source can be automatically shut off.

[0030] Please refer to this carefully. Figures 2 to 7 The breathable and wear-resistant microporous lining 208 is composed of a side-inverted T-shaped inner lining block 2081, a vertical protrusion 2082, and a horizontal reinforcing rib 2083. The vertical protrusion 2082 and the horizontal reinforcing rib 2083 are integrally formed from the horizontal reinforcing rib 2083, and the vertical protrusion 2082 and the horizontal reinforcing rib 2083 are perpendicular to each other. The side-inverted T-shaped inner lining block 2081, the vertical protrusion 2082, and the horizontal reinforcing rib 2083 are integrally formed by adding a pore-forming agent and a molding process.

[0031] In this embodiment: the structural strength of the side-inverted T-shaped inner liner block 2081 can be increased by the structural arrangement of the vertical protrusion 2082 and the horizontal reinforcing rib 2083; in addition, the breathable and wear-resistant microporous liner 208 has through and uniform micron-level pores inside, which can allow gas to permeate out, but solid particles have difficulty entering, thus fundamentally solving the problem of pore blockage.

[0032] The micron-level channels inside the breathable and wear-resistant microporous lining 208 can be manufactured using the following processes: A certain proportion of pore-forming agent (common pore-forming agents include sawdust, carbon powder, starch, paraffin wax, polystyrene microspheres, etc.) is uniformly mixed into the refractory raw materials. After mixing, the materials are usually formed into a blank by machine pressing or casting, and then sintered at high temperature. During the high-temperature sintering process, the pore-forming agent will burn out or volatilize, leaving the original voids to form micropores. For example, reaction sintered silicon carbide formed by silicon carbide materials has good high temperature resistance, alkali corrosion resistance, good air tightness, and high strength, which can meet the alumina calcination process environment.

[0033] Please refer to this carefully. Figures 4 to 7 A bottom support plate 206 is fixed to the inner bottom of the sealing plate 203, and two limiting seats 207 are symmetrically fixed to the upper surface of the bottom support plate 206; the bottom of the side-inverted T-shaped inner liner block 2081 is attached to the upper surface of the sealing plate 203, and the vertical protrusion 2082 is inserted into the inner side of the limiting seat 207 to realize the composition of the breathable and wear-resistant microporous liner 208 and the sealing plate 203.

[0034] The disassembly and assembly unit includes a fixed guide rod 209 and a limiting block 210. The fixed guide rod 209 is symmetrically fixed to the outside of the conical ring cover 201 with the center line of the side-tilted T-shaped compartment 202 as the center and passes through the sealing plate 203. The sealing plate 203 has a sleeve hole that matches the outer wall of the fixed guide rod 209. The limiting block 210 is fixed to the side of the fixed guide rod 209 away from the conical ring cover 201 and is used to limit the outward movement of the sealing plate 203.

[0035] In this embodiment, it should be noted that the sealing plate 203 and the conical ring cover 201 can be fixed by bolts. The sealing plate 203 has mounting holes, and the conical ring cover 201 has corresponding screw holes on its outer side. The sealing plate 203 can be installed by bolts passing through the mounting holes and being threaded into the screw holes.

[0036] In practical applications, the breathable and wear-resistant microporous liner 208 will inevitably experience wear and damage. Therefore, it is necessary to replace the breathable and wear-resistant microporous liner 208 periodically (or when damage is discovered). The procedure is as follows: First, stop the machine and wait for the temperature to drop. Then, remove the bolts. Next, manually pull the sealing plate 203 outward. The sealing plate 203 moves horizontally along the trajectory of the fixed guide rod 209 (it should be noted that the fixed guide rod 209 is in a horizontal state). At the same time, the sealing plate 203 moves the breathable and wear-resistant microporous liner 208 out of the side-tilting T-shaped compartment 202. This makes it easier for maintenance personnel to access the breathable and wear-resistant microporous liner 208 and remove it. After the operation, place the new breathable and wear-resistant microporous liner 208 on the bottom support plate 206, and insert the bottom of its vertical protrusion 2082 into the limiting bracket 207 to achieve the limiting installation of the breathable and wear-resistant microporous liner 208; then, push the sealing plate 203 close to the conical ring cover 201, and then install the bolts. At this time, the breathable and wear-resistant microporous liner 208 is pressed into the side-tilting T-shaped compartment 202, thus completing the replacement of the breathable and wear-resistant microporous liner 208.

[0037] Please refer to this carefully. Figures 2 to 7 High-temperature resistant seals are provided at the contact points between the inner side of the side-tilting T-shaped compartment 202 and the contact points between the side-tilting T-shaped inner liner block 2081 and the bottom support plate 206. A pressure detection port 205 that communicates with the air chamber is also fixed on the outer side of the sealing plate 203.

[0038] In this embodiment: the secondary structure ensures a good sealing environment inside the air chamber. The pressure detection port 205 is used to install a pressure transmitter to monitor the internal pressure of the air chamber. During normal operation, the air chamber is a relatively closed space. During pulse jetting, the pressure rises and falls regularly. If cracks or perforations appear in the breathable and wear-resistant microporous lining 208, high-pressure gas will leak into the cone 103, causing an abnormal drop in air chamber pressure or an inability to maintain pressure. Therefore, by monitoring the air pressure with a pressure transmitter, if the pressure peak during jetting is found to be significantly lower than the normal value, or if the pressure cannot be maintained during non-jetting periods (negative pressure is evacuated), it may mean that the breathable and wear-resistant microporous lining 208 is leaking, thereby achieving the purpose of monitoring whether the breathable and wear-resistant microporous lining 208 is damaged.

[0039] Please refer to this carefully. Figures 1 to 7 Multiple conical ring covers 201 are evenly arranged along the vertical trajectory of the conical cylinder 103, and multiple side-inverted T-shaped compartments 202 are arranged in a ring on a single conical ring cover 201. The number and position of the through slots 106 inside the conical cylinder 103 correspond one-to-one with the number and position of the side-inverted T-shaped compartments 202. Two vertically adjacent through slots 106 are staggered along the circumferential direction, and the inner wall surface of the side-inverted T-shaped inner liner block 2081 is flush with the inner wall surface of the conical cylinder 103.

[0040] In this embodiment, it should be noted that the air chambers inside the multiple side-tilting T-shaped chambers 202 are equipped with independent air inlet pipes and valves, which can independently control the air intake of each air chamber. In this way, each air chamber can take turns to intake air for short-term blowing, which can achieve all-round disturbance of the material inside the cone 103 while reducing continuous interference with the main airflow.

[0041] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for recovering waste heat from alumina roasting, characterized in that, The specific steps are as follows: Step 1: Place the aluminum hydroxide raw material at room temperature into a Venturi dryer to complete the pre-drying treatment; Step 2: The material dried by the Venturi dryer is sent into the cyclone preheater system. Under the negative pressure of the system, the material flows from top to bottom through the first-stage cyclone preheater, the second-stage cyclone preheater, the third-stage cyclone preheater, ..., the Nth-stage cyclone preheater in the cyclone preheater system, and exchanges heat with the high-temperature flue gas rising from the roasting furnace in a counter-current manner. Step 3: In each stage of the cyclone preheater, the flue gas flows upward and the material sinks downward. The material is continuously heated by the flue gas, and the flue gas is continuously cooled by the material. After each stage completes the gas-solid heat exchange, the preheated material and the cooled flue gas are separated by the centrifugal force of the cyclone preheater: the separated material enters the next stage of the cyclone preheater to continue absorbing heat, and the separated flue gas enters the previous stage of the cyclone preheater to continue releasing heat. Step 4: The material, which has been preheated to the set temperature through multiple stages of the Nth stage cyclone preheater, is discharged from the bottom of the cyclone preheater system and directly sent into the calcining furnace for high-temperature calcination. After calcination, alumina product is produced. Step 5: The low-temperature flue gas discharged from the first-stage cyclone preheater is led out to the purification system and discharged after purification treatment to meet the standards.

2. The alumina roasting waste heat recovery equipment according to claim 1, characterized in that, Includes the cyclone preheater system described in step two, wherein the cyclone preheater system includes at least three stages of cyclone preheaters; The cyclone preheater includes a cyclone assembly (1) consisting of an inlet volute (101), an outer cylinder (102), a cone (103), a discharge port (104), and an outlet inner cylinder (105). The inlet volute (101), the outer cylinder (102), and the cone (103) are connected and communicated sequentially from top to bottom. The discharge port (104) is fixed to the bottom of the cone (103) and communicates with the cone (103), providing a channel for the heated and separated material to enter the next stage; the exhaust inner cylinder (105) is fixed to the top of the intake volute (101) and extends downward into the outer cylinder (102), providing a channel for the separated flue gas to enter the next stage; an anti-clogging disturbance component (2) is provided on the outside of the cone (103), which is used to disturb the material inside the cone (103); The anti-clogging disturbance component (2) includes an airflow disturbance unit and a disassembly unit; the airflow disturbance unit uses external high-pressure pulse gas to disturb the material inside the cone (103); the disassembly unit is used to provide support and guidance for the disassembly and maintenance of the airflow disturbance unit.

3. The alumina roasting waste heat recovery equipment according to claim 2, characterized in that, The airflow disturbance unit includes a conical ring cover (201), a side-tilting T-shaped compartment (202), a sealing plate (203), an air inlet (204), and a breathable and wear-resistant microporous lining (208). The conical ring cover (201) is fixed to the outside of the conical cylinder (103). The side-tilting T-shaped compartment (202) is opened inside the conical ring cover (201) and penetrates the inner and outer walls of the conical ring cover (201). A through slot (106) is opened on the inner side of the conical cylinder (103) at a position aligned with the side-tilting T-shaped compartment (202). The through slot (106) is connected and communicates with the side-tilting T-shaped compartment (202). The breathable and wear-resistant microporous lining (208) is installed inside the side-inverted T-shaped compartment (202) and extends into the inside of the through slot (106); The sealing plate (203) is installed on the outside of the conical ring cover (201) and forms a seal on the opening of the side-inverted T-shaped compartment (202); The side-tilting T-shaped chamber (202) is located between the sealing plate (203) and the breathable and wear-resistant microporous lining (208) to form an air chamber. The air inlet (204) is fixed to the outside of the sealing plate (203) and passes through the sealing plate (203) to communicate with the air chamber. The air inlet (204) is used to communicate with an external air source. External high-pressure pulsed gas enters the gas chamber through the air inlet (204) and then evenly passes through the breathable and wear-resistant microporous lining (208) into the interior of the cone (103) to achieve the effect of disturbing the material inside the cone (103).

4. The alumina roasting waste heat recovery equipment according to claim 3, characterized in that, The breathable and wear-resistant microporous lining (208) is composed of a side-inverted T-shaped inner lining block (2081), a vertical protrusion (2082), and a horizontal reinforcing rib (2083). The vertical protrusion (2082) and the horizontal reinforcing rib (2083) are integrally formed on the horizontal reinforcing rib (2083), and the vertical protrusion (2082) and the horizontal reinforcing rib (2083) are perpendicular to each other. The side-inverted T-shaped inner liner (2081), vertical protrusion (2082), and transverse reinforcing rib (2083) are integrally formed by adding a pore-forming agent and molding process.

5. The alumina roasting waste heat recovery equipment according to claim 4, characterized in that, The bottom inner side of the sealing plate (203) is fixed with a bottom support plate (206), and two limiting brackets (207) are symmetrically fixed on the upper surface of the bottom support plate (206). The bottom of the side-inverted T-shaped inner liner block (2081) is attached to the upper surface of the sealing plate (203), and the vertical protrusion (2082) is inserted into the inner side of the limiting card seat (207) to realize the composition of the breathable and wear-resistant microporous liner (208) and the sealing plate (203).

6. The alumina roasting waste heat recovery equipment according to claim 5, characterized in that, High-temperature resistant seals are provided at the contact points between the inner side of the side-tilted T-shaped chamber (202) and the contact points between the side-tilted T-shaped inner liner block (2081) and the bottom support plate (206). A pressure detection port (205) connected to the air chamber is also fixed on the outer side of the sealing plate (203).

7. The alumina roasting waste heat recovery equipment according to claim 3, characterized in that, The assembly / disassembly unit includes a fixed guide rod (209) and a limiting block (210). The fixed guide rod (209) is symmetrically fixed to the outside of the conical ring cover (201) with the center line of the side-inverted T-shaped compartment (202) as the center and passes through the sealing plate (203). The sealing plate (203) has a sleeve hole that matches the outer wall of the fixed guide rod (209). The limiting block (210) is fixed to the side of the fixed guide rod (209) away from the conical ring cover (201) and is used to limit the outward movement of the sealing plate (203).

8. The alumina roasting waste heat recovery equipment according to claim 6, characterized in that, The conical ring cover (201) is uniformly arranged in multiple ways along the vertical trajectory of the cone (103), and multiple side-inverted T-shaped compartments (202) are arranged in a ring on a single conical ring cover (201). The number and position of the through slots (106) inside the cone (103) correspond one-to-one with the number and position of the side-inverted T-shaped compartments (202).

9. The alumina roasting waste heat recovery equipment according to claim 8, characterized in that, The two vertically adjacent through slots (106) are staggered along the circumferential direction, and the inner wall surface of the side-inverted T-shaped inner liner block (2081) is flush with the inner wall surface of the cone (103).

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