Alumina waste heat recovery device

Abstract

The utility model discloses an alumina waste heat recovery device, solved the problem that the alumina calcining furnace in the prior art is not easy to recover the waste heat in the process of reducing from 180~240 degrees Celsius to below 80 degrees Celsius after being converted into alumina through reaction. The utility model discloses a horizontally arranged outer cylinder and inner cylinder, and the inner cylinder is rotatably arranged in the outer cylinder, and the inner cylinder is uniformly distributed with the heat exchange pipe of horizontal arrangement, and the upper portion of outer cylinder and the upper portion of inner cylinder are equipped with the feed port, and the lower portion of outer cylinder and the lower portion of inner cylinder are equipped with the discharge gate, and the feed port and discharge gate are arranged in the upper and lower correspondence, and the inner cylinder is divided into left chamber and right chamber through the baffle, and the left chamber or right chamber bottom is equipped with the counterweight. The utility model can make the alumina slowly flow in the heat exchanger, and the air in the heat exchange pipe is fully heat exchanged, and the high temperature waste heat of alumina is absorbed to heat the air inlet of alumina calcining furnace, and the purpose of waste heat recovery and utilization is achieved.

Description

Technical Field

[0001] This utility model relates to the field of energy conservation and environmental protection technology, and in particular to a waste heat recovery device for an aluminum hydroxide roasting furnace. Background Technology

[0002] After the aluminum hydroxide calcining furnace reacts and converts to alumina, the temperature drops to 180-240℃ after four-stage cooling, and then is further cooled to below 80℃ by tubular coolers with cooling water. Currently, this heat cannot be effectively recovered in production, resulting in its loss. Existing waste heat recovery devices for aluminum hydroxide calcining furnaces, such as the waste heat recovery device and process for phase change dust removal in aluminum hydroxide calcining furnace flue gas (application publication number CN 111380368 A), employ a method of first heat exchange dust removal and then spray dust removal to reduce energy consumption, recover and utilize energy, and improve dust removal efficiency, thus achieving energy conservation and emission reduction. However, this method is mainly used for waste heat recovery from the flue gas of aluminum hydroxide calcining furnaces and cannot efficiently recover the waste heat generated during the process of the aluminum hydroxide calcining furnace reacting and converting to alumina, then cooling to 180-240℃ after four-stage cooling, and then further cooling to below 80℃ by tubular coolers with cooling water. Therefore, it is necessary to develop a recovery device to recover this heat. Utility Model Content

[0003] To address the shortcomings in the aforementioned background technology, this utility model proposes an alumina waste heat recovery device, which solves the problem that waste heat is difficult to recover during the cooling process of the aluminum hydroxide roasting furnace from 180~240 degrees Celsius to below 80 degrees Celsius after the aluminum hydroxide roasting furnace is converted into alumina by reaction.

[0004] The technical solution of this utility model is implemented as follows: An alumina waste heat recovery device includes a horizontally arranged outer cylinder and an inner cylinder. The inner cylinder is rotatably arranged inside the outer cylinder. Horizontally arranged heat exchange tubes are evenly distributed inside the inner cylinder. A feed inlet is provided at the upper part of the outer cylinder and the upper part of the inner cylinder. A discharge outlet is provided at the lower part of the outer cylinder and the lower part of the inner cylinder. The feed inlet and the discharge outlet are arranged vertically and vertically. The inner cylinder is divided into a left chamber and a right chamber by a partition. A counterweight is provided at the bottom of the left chamber or the right chamber. Because of the counterweight, the openings of the feed inlets in the left and right chambers are different. The chamber without the counterweight has a larger feed inlet opening, while the chamber with the counterweight has a smaller feed inlet opening. The chamber with the larger feed inlet opening accumulates more alumina, resulting in greater weight and causing the inner cylinder to rotate in the corresponding direction. At this time, the feed inlet opening of the chamber that originally had a smaller opening gradually increases. By repeating the above process, the alumina flows slowly in the inner cylinder, fully exchanging heat with the air in the heating tube and efficiently absorbing the high-temperature waste heat of the alumina.

[0005] In a further preferred embodiment, the outer cylinder and the inner cylinder are arranged coaxially, and a sealing structure is provided between the outer cylinder and the inner cylinder; this prevents hot air backflow and improves waste heat recovery efficiency.

[0006] Further preferably, the sealing structure includes a plurality of outer sealing rings disposed on the inner wall of the outer cylinder and a plurality of inner sealing rings disposed on the outer wall of the inner cylinder, the outer sealing rings and inner sealing rings being arranged in a cross pattern to form a labyrinth-type sealing structure; the labyrinth-type sealing structure improves the sealing effect.

[0007] Further optimization involves having a larger diameter for the upper feed inlet of the outer cylinder than for the upper feed inlet of the inner cylinder; and a feed cone is provided inside the upper feed inlet of the outer cylinder to facilitate rapid feeding.

[0008] Further optimization involves having a larger diameter at the lower outlet of the outer cylinder than at the lower outlet of the inner cylinder.

[0009] In a further preferred embodiment, a hollow shaft is provided inside the inner cylinder along the axial direction, and a fixed shaft passes through the hollow shaft. The two ends of the fixed shaft extend out of the inner cylinder and are fixedly connected to the outer cylinder through support rods. A rolling bearing is provided between the hollow shaft and the fixed shaft.

[0010] In a further preferred embodiment, both ends of the inner cylinder are provided with tube sheets, and both ends of the heat exchange tubes are fixedly connected to the corresponding tube sheets. The heat exchange tubes in the left chamber of the inner cylinder and the heat exchange tubes in the right chamber of the inner cylinder are arranged symmetrically.

[0011] Further preferably, the heat exchange tube has a downwardly inclined steel strip on the side away from the partition.

[0012] Further preferably, the steel strip is welded onto the heat exchange tube, and the inclination angle of the steel strip is 5~30°.

[0013] In a further preferred embodiment, the air outlet of the outer cylinder is connected to the air inlet pipe of the roasting furnace, and the air inlet of the outer cylinder is connected to the external air inlet pipe.

[0014] The beneficial effects of this invention are as follows: This invention, through the rotatable inner cylinder and internal partitions, allows different amounts of alumina material to enter the left and right chambers of the inner cylinder using counterweights. The material's own weight then allows the alumina to flow slowly within the heat exchanger composed of the inner cylinder and heat exchange tubes, extending the heat exchange time and increasing the contact area. This ensures sufficient heat exchange with the air inside the heat exchange tubes, absorbing the high-temperature waste heat from the alumina to heat the intake air of the alumina roasting furnace, achieving efficient waste heat recovery and utilization. This invention employs a rotary waste heat recovery design, significantly improving the efficiency of alumina waste heat recovery. Due to its high heat recovery capacity, it reduces dependence on external energy sources, thereby lowering long-term operating costs and possessing high promotional value. Attached Figure Description

[0015] To more clearly illustrate the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a cross-sectional schematic diagram of the present invention.

[0017] Figure 2 This is a schematic diagram of the longitudinal section of this utility model. Detailed Implementation

[0018] 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.

[0019] Example 1, as Figure 1As shown, an alumina waste heat recovery device includes a horizontally arranged outer cylinder 1 and an inner cylinder 2. In actual use, the air outlet of the outer cylinder 1 is connected to the air inlet pipe 18 of the roasting furnace, and the air inlet of the outer cylinder 1 is connected to an external air inlet pipe 19. The external air inlet pipe 19 introduces external cold air into the heat exchange tubes, which then exchange heat with the alumina. The hot air in the heat exchange tubes is introduced into the roasting furnace through the outer cylinder to heat the air entering the roasting furnace, thus achieving the purpose of waste heat utilization. In this embodiment, the inner cylinder 2 is rotatably arranged inside the outer cylinder 1, meaning that the inner cylinder can rotate relative to the outer cylinder. Horizontally arranged heat exchange tubes 11 are evenly distributed inside the inner cylinder 2, forming a heat exchanger. Both the upper part of the outer cylinder 1 and the upper part of the inner cylinder 2 are provided with inlets 3, and both the lower part of the outer cylinder 1 and the lower part of the inner cylinder 2 are provided with outlets 5. The inlets 3 and outlets 5 are arranged vertically and vertically. The alumina material enters the heat exchanger through the inlet 3, undergoes heat exchange and cooling in the heat exchanger, and then flows out through the outlet. The inner cylinder 2 is divided into a left chamber and a right chamber by a partition 15. A counterweight 6 is provided at the bottom of the left or right chamber. It should be noted that the partition 15 divides the interior of the inner cylinder into a left chamber and a right chamber. That is to say, when the counterweight is not provided, the partition is located at the center line connecting the inlet 3 and the outlet 5. Because of the counterweight, the openings of the feed inlets in the left and right chambers are different. The chambers without counterweights have larger feed inlet openings, while the chambers with counterweights have smaller feed inlet openings. The chambers with larger feed inlet openings accumulate more alumina, resulting in greater weight and causing the inner cylinder to rotate in the corresponding direction. At this time, the feed inlet openings of the chambers that originally had smaller openings gradually increase. By repeating the above process, the alumina flows slowly in the inner cylinder, fully exchanging heat with the air in the outer cylinder and efficiently absorbing the high-temperature waste heat of the alumina.

[0020] Example 2 provides an alumina waste heat recovery device. Based on Example 1, this embodiment further optimizes the arrangement of the outer cylinder 1 and inner cylinder 2 along a coaxial axis, with an annular gap between them. A sealing structure is installed between the outer cylinder 1 and inner cylinder 2 to seal this annular gap. Due to the labyrinth seal between the inner and outer pipe walls, most of the air inside the heat exchange tube enters the outlet of the outer cylinder through the heat exchanger, preventing short-circuiting between the inner and outer pipe walls. Specifically, the sealing structure in this embodiment includes several outer sealing rings 8 disposed on the inner wall of the outer cylinder 1 and several inner sealing rings 9 disposed on the outer wall of the inner cylinder 2. The outer sealing rings 8 are equidistantly spaced, and the inner sealing rings 9 are also equidistantly spaced. The outer sealing rings 8 and inner sealing rings 9 are arranged in a cross pattern to form a labyrinth seal structure, further improving the sealing effect and effectively preventing hot air backflow.

[0021] In this embodiment, the diameter of the upper feed inlet 3 of the outer cylinder 1 is larger than the diameter of the upper feed inlet 3 of the inner cylinder 2, ensuring that alumina can smoothly and continuously enter the inner cylinder. A feed cone 16 is provided inside the upper feed inlet 3 of the outer cylinder 1 to facilitate feeding. The diameter of the lower discharge outlet 5 of the outer cylinder 1 is larger than the diameter of the lower discharge outlet 5 of the inner cylinder 2, ensuring that the alumina material after heat exchange can be smoothly discharged.

[0022] like Figure 2 As shown in the figure, in this embodiment, the counterweight is set at the bottom of the right chamber as an example. The inner cylinder and multiple heat exchange tubes form a heat exchanger. Because the entire heat exchanger can rotate freely, the heat exchanger tilts to the right under the action of the counterweight. The opening of the feed port corresponding to the left chamber is greater than the opening of the feed port corresponding to the right chamber. Therefore, more alumina enters the heat exchanger from the left. The alumina accumulates layer by layer on the heat exchange tubes, transferring heat to the air inside the heat exchange tubes. When more alumina accumulates on the left, the heat exchanger rotates to the left under the action of gravity. At the same time, the alumina on the left slowly slides down. At this time, the opening of the feed port corresponding to the left chamber gradually becomes smaller than the opening of the feed port corresponding to the right chamber. Then, due to the increase in the alumina feed on the right, more alumina accumulates on the right, and the heat exchanger rotates to the right again. This process repeats, and the alumina flows slowly in the heat exchanger, transferring heat to the air inside the heat exchange tubes. Due to the labyrinth seal between the inner and outer tube walls, most of the air inside the heat exchange tubes passes through the heat exchanger and does not short-circuit between the inner and outer tube walls. This invention allows alumina to flow slowly within a heat exchanger, fully exchanging heat with the air inside the heat exchange tubes. It absorbs the high-temperature waste heat from the alumina to heat the intake air of the alumina roasting furnace, thus achieving the purpose of waste heat utilization.

[0023] Example 3: An alumina waste heat recovery device. Based on Example 2, this embodiment further preferably includes a hollow shaft 17 along the axial direction inside the inner cylinder 2. The hollow shaft is also a shaft-tube structure. A fixed shaft 14 passes through the hollow shaft 17. Both ends of the fixed shaft 14 extend out of the inner cylinder 2 and are fixedly connected to the outer cylinder 1 via support rods 7. The number of support rods can be set as needed to ensure stable support for the fixed shaft. A rolling bearing 13 is provided between the hollow shaft 17 and the fixed shaft 14 to ensure that the inner cylinder can rotate flexibly relative to the outer cylinder, enabling the alumina to flow slowly within the heat exchanger and improving heat exchange efficiency.

[0024] In this embodiment, the inner cylinder 2 is a cylindrical structure with openings at both ends. Tube sheets 10 are provided at both ends, serving as supports and fixings for the heat exchange tubes. Specifically, both ends of the heat exchange tubes 11 are fixedly connected to their respective tube sheets 10, ensuring the stability of their connection to the inner cylinder. The heat exchange tubes 11 in the left chamber and right chamber of the inner cylinder 2 are symmetrically arranged; all heat exchange tubes are arranged in parallel.

[0025] In this embodiment, the heat exchange tube 11 has a downwardly inclined steel strip 12 on the side away from the partition 15. This steel strip can be made of flat steel. Specifically, the heat exchange tube is divided into left and right parts, separated by a partition. The flat steel on the left heat exchange tube is on the left side, and the flat steel on the right heat exchange tube is on the right side. The steel strip 12 is welded to one side wall of the heat exchange tube 11, and the inclination angle of the steel strip 12 is 5~30°, preferably 15°, to ensure that the accumulated alumina can slide off smoothly, allowing the alumina to flow slowly within the heat exchanger, thus extending the heat exchange contact time and contact area.

[0026] In this embodiment, taking the counterweight at the bottom of the left chamber as an example, the inner cylinder and multiple heat exchange tubes form a heat exchanger. Because the entire heat exchanger can rotate freely, it tilts to the left under the action of the counterweight. The opening of the feed inlet corresponding to the right chamber is greater than that of the feed inlet corresponding to the left chamber, so more alumina enters the heat exchanger from the right side. The alumina accumulates layer by layer on the heat exchange tubes and steel strips, transferring heat to the air inside the heat exchange tubes. When more alumina accumulates on the right side, the heat exchanger rotates to the right under the action of gravity, and the alumina on the right side slowly slides down. At this time, the opening of the feed inlet corresponding to the right chamber gradually becomes smaller than that of the feed inlet corresponding to the left chamber. Then, due to the increase in alumina feed on the left side, more alumina accumulates on the left side, and the heat exchanger rotates to the left again. This process repeats, and the alumina flows slowly inside the heat exchanger, transferring heat to the air inside the heat exchange tubes. Due to the labyrinth seal between the inner and outer tube walls, most of the air inside the heat exchange tubes passes through the heat exchanger without short-circuiting between the inner and outer tube walls. This invention allows alumina to flow slowly within a heat exchanger, fully exchanging heat with the air inside the heat exchange tubes. It absorbs the high-temperature waste heat from the alumina to heat the intake air of the alumina roasting furnace, thus achieving the purpose of waste heat utilization.

[0027] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. An alumina waste heat recovery device, comprising a horizontally arranged outer cylinder (1) and an inner cylinder (2), characterized in that: The inner cylinder (2) is rotatably set inside the outer cylinder (1). The inner cylinder (2) is evenly distributed with horizontally arranged heat exchange tubes (11). The upper part of the outer cylinder (1) and the upper part of the inner cylinder (2) are provided with inlet (3). The lower part of the outer cylinder (1) and the lower part of the inner cylinder (2) are provided with outlet (5). The inlet (3) and outlet (5) are arranged vertically and vertically. The inner cylinder (2) is divided into a left chamber and a right chamber by a partition (15). The bottom of the left chamber or the right chamber is provided with a counterweight (6).

2. The alumina waste heat recovery device according to claim 1, characterized in that: The outer cylinder (1) and the inner cylinder (2) are arranged on the same axis, and a sealing structure is provided between the outer cylinder (1) and the inner cylinder (2).

3. The alumina waste heat recovery device according to claim 2, characterized in that: The sealing structure includes several outer sealing rings (8) disposed on the inner wall of the outer cylinder (1) and several inner sealing rings (9) disposed on the outer wall of the inner cylinder (2). The outer sealing rings (8) and the inner sealing rings (9) are arranged in a cross pattern to form a labyrinth-type sealing structure.

4. The alumina waste heat recovery device according to any one of claims 1 to 3, characterized in that: The diameter of the upper feed inlet (3) of the outer cylinder (1) is larger than the diameter of the upper feed inlet (3) of the inner cylinder (2); the upper feed inlet (3) of the outer cylinder (1) is provided with a feed cone (16).

5. The alumina waste heat recovery device according to claim 4, characterized in that: The diameter of the lower discharge port (5) of the outer cylinder (1) is larger than the diameter of the lower discharge port (5) of the inner cylinder (2).

6. The alumina waste heat recovery device according to any one of claims 1 to 3 and 5, characterized in that: The inner cylinder (2) is provided with a hollow shaft (17) along the axial direction. A fixed shaft (14) is passed through the hollow shaft (17). Both ends of the fixed shaft (14) extend out of the inner cylinder (2) and are fixedly connected to the outer cylinder (1) through the support rod (7). A rolling bearing (13) is provided between the hollow shaft (17) and the fixed shaft (14).

7. The alumina waste heat recovery device according to claim 6, characterized in that: Both ends of the inner cylinder (2) are provided with tube sheets (10), and both ends of the heat exchange tube (11) are fixedly connected to the corresponding tube sheets (10). The heat exchange tube (11) in the left chamber of the inner cylinder (2) and the heat exchange tube (11) in the right chamber of the inner cylinder (2) are symmetrically arranged.

8. The alumina waste heat recovery device according to claim 7, characterized in that: The heat exchange tube (11) is provided with a downwardly inclined steel strip (12) on the side away from the partition (15).

9. The alumina waste heat recovery device according to claim 8, characterized in that: The steel strip (12) is welded onto the heat exchange tube (11), and the inclination angle of the steel strip (12) is 5~30°.

10. The alumina waste heat recovery device according to any one of claims 1 to 3, 8, and 9, characterized in that: The air outlet of the outer cylinder (1) is connected to the air inlet pipe (18) of the roasting furnace, and the air inlet of the outer cylinder (1) is connected to the external air inlet pipe (19).

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