An active electrolytic cell side wall waste heat recovery system

Abstract

The present invention discloses an active electrolytic cell side wall waste heat recovery system, comprising an electrolytic cell, the side wall of which is divided into a plurality of heat exchange module installation area units; an upper cover plate, which is located at the upper edge of the electrolytic cell side wall; a side cover plate, which is located on the side of the electrolytic cell side wall and is parallel to the side wall; a bottom plate, which is located at the lower edge of the electrolytic cell side wall and forms a closed space together with the side cover plate and the upper cover plate; a heat exchanger, which is composed of a plurality of heat exchange modules, which are respectively installed in the plurality of heat exchange module installation area units. In view of the fact that the total amount of side wall waste heat is difficult to recover at present, this application divides the side wall into a plurality of small areas, and designs and manufactures a corresponding heat exchanger in each small area. Therefore, the heat exchangers should be arranged with these small areas as units, and these heat exchangers should be connected together in parallel or in series to recover the side wall waste heat.

Description

Technical Field

[0001] The present invention relates to electrolytic cell waste heat recovery technology, and mainly relates to an active electrolytic cell side wall waste heat recovery system. Background Art

[0002] The electrolytic aluminum process consumes a significant amount of electricity. Furthermore, due to its low energy efficiency, electrolytic aluminum production is a highly energy-intensive industry. The energy efficiency of electrolytic aluminum production is less than 50%, with over half of the input energy lost as various forms of waste heat. Flue gas heat and sidewall heat account for the largest proportion of this waste heat. Sidewall heat loss accounts for approximately 36% of total heat losses and 18% of total energy input.

[0003] Because the inside of the electrolytic cell sidewalls must be protected by a slab to protect the cathode and other components, the required process temperature on the cathode side of the sidewall is determined by the thickness of the slab. Since the electrolyte operating temperature remains constant at around 950°C during production, the thickness and thermal conductivity of the slab remain constant. Therefore, a certain amount of heat must be released from the sidewalls to meet process requirements. Currently, this waste heat is released passively to meet the slab thickness requirement. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies of the above-mentioned prior art and to provide an active electrolytic cell side wall waste heat recovery system. The system adopts active side wall waste heat recovery technology to recover the side wall waste heat under controllable conditions. The amount of recovered side wall waste heat can be adjusted according to the size of the heat flow. This not only ensures the thickness of the side wall trough and ensures the safe detection of the side wall, but also can efficiently recover the side wall waste heat, which can be used to improve the comprehensive energy utilization efficiency of the electrolytic cell.

[0005] To achieve the above object, the technical solution of the present invention is:

[0006] An active electrolytic cell sidewall waste heat recovery system, comprising:

[0007] The electrolytic cell has a side wall divided into a number of heat exchange module installation area units;

[0008] The upper cover plate is located outside the upper edge of the side wall of the electrolytic cell and forms a relatively closed space with the side cover plate and the bottom plate to improve the heat exchange efficiency;

[0009] The side cover plate is located on the side of the electrolytic cell side wall, parallel to the side wall, and forms a relatively closed space with the upper cover plate and the bottom plate to improve the heat exchange efficiency;

[0010] The bottom plate is located at the lower edge of the side wall of the electrolytic cell and forms a relatively closed space with the side cover plate and the upper cover plate for active recovery of waste heat;

[0011] The heat exchanger is composed of a plurality of heat exchange modules, which are respectively installed in the plurality of heat exchange module installation area units.

[0012] Furthermore, the active electrolytic cell side wall waste heat recovery system further comprises:

[0013] Thermal imagers are used to monitor the temperature of the electrolytic cell side walls to ensure safe operation of the system.

[0014] Furthermore, the active electrolytic cell side wall waste heat recovery system further comprises:

[0015] The partition is located between the side wall of the electrolytic cell and the heat exchanger; the partition has holes or gaps and is composed of two or more layers. The visible area between the heat exchanger and the side wall can be changed by moving different layers of partitions to adjust the heat exchange capacity of the heat exchanger.

[0016] Furthermore, the active electrolytic cell side wall waste heat recovery system further comprises:

[0017] Support rods are used to support and position the heat exchanger and side covers.

[0018] Furthermore, different heat exchange modules are connected in parallel or in series through valve combinations; by adjusting the connection mode of different heat exchange modules, different heat exchange amounts can be achieved.

[0019] Furthermore, the heat exchange amount is further adjusted by adjusting the flow rate of the cooling medium in the heat exchanger to ensure the heat exchange amount that needs to be extracted.

[0020] Furthermore, the side cover plate is provided with a thermal imager observation hole and a support rod hole.

[0021] Furthermore, a handle is provided on the side cover.

[0022] Furthermore, the thermal imager is operated in the form of one host computer and multiple cameras, and the cameras can be switched with each other.

[0023] Furthermore, the active electrolytic cell side wall waste heat recovery system further comprises:

[0024] An alarm is configured to sound an alarm when the temperature detected by the thermal imager is higher than a set value.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] In response to the current problem of difficulty in recovering waste heat from the side walls, this application proposes a specific solution. The main problem with recovering waste heat from the side walls is that the side walls are not in a good position to place a heat exchanger, and various pipes and wires are arranged on the surface of the side walls. In order to overcome this shortcoming, this application divides the side walls into several small areas, and designs and manufactures corresponding heat exchangers in each small area. Therefore, the heat exchanger modules should be arranged in units of these small areas, and these heat exchanger modules are connected together in parallel or series to recover waste heat from the side walls, thereby solving the overall defect of difficulty in placing large heat exchangers. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of the composition of an active electrolytic cell sidewall waste heat recovery system provided by an embodiment of the present invention;

[0028] Figure 2 Schematic diagram of the composition of the heat exchanger;

[0029] In the figure: 1. electrolytic cell; 2. upper cover; 3. side cover; 4. bottom plate; 5. heat exchange module; 6. thermal imager; 7. partition; 8. support rod. DETAILED DESCRIPTION

[0030] Example:

[0031] The technical solution of the present invention is further described below with reference to the accompanying drawings and embodiments.

[0032] See Figure 1 As shown, the active electrolytic cell side wall waste heat recovery system provided in this embodiment mainly includes an electrolytic cell 1, an upper cover plate 2, a side cover plate 3, a bottom plate 4 and a heat exchanger.

[0033] The electrolytic cell 1 is where the aluminum electrolysis process takes place and consists of a cell body, cathode, anode, electrolyte, and exhaust system. Within the cell, electrical energy is input through the cathode and anode to complete the electrochemical process. The electrochemical process requires a certain temperature for proper operation, generally controlled between 920 and 970°C depending on process requirements. The temperature in the upper chamber of the cell is generally below 300°C. Due to the infiltration of flue gases from the workshop through the exhaust system, the flue gas temperature is generally below 200°C. This waste heat accounts for 36% of the total waste heat and 18% of the total energy input. Some companies are considering recycling this waste heat. In addition, some heat is lost through the bottom of the cell. The waste heat emitted through the sidewalls is comparable to the heat removed by the flue gas, but recovery is difficult. This application addresses the current difficulty in recovering sidewall waste heat and proposes a specific solution. The primary challenge with recovering sidewall waste heat is that the sidewalls are not ideally located for heat exchangers, as various pipes and wires are located on the sidewall surfaces. In order to overcome this shortcoming, the present application divides the side wall into several small areas, and designs and manufactures a corresponding heat exchanger in each small area. Therefore, the heat exchangers should be arranged with these small areas as units, and these heat exchangers should be connected together in parallel or series to recover the waste heat of the side wall. Since the thickness of the side wall groove is determined by the heating process, inside the side wall of the electrolytic cell, inside the graphite or carbon material, and in the solution of the present application, an active side wall waste heat recovery technology is adopted to recover the side wall waste heat under controllable conditions. The amount of recovered side wall waste heat can be adjusted according to the size of the heat flow. It can not only ensure the thickness of the side wall groove and ensure the safe detection of the side wall, but also efficiently recover the side wall waste heat, and use it to improve the comprehensive energy utilization efficiency of the electrolytic cell. Specifically, the present application adopts the following technical means to achieve this.

[0034] The upper cover is located on the upper edge of the electrolytic cell sidewalls and, together with the side covers and bottom plate, forms a closed space. This allows the heat that was originally carried away by natural convection to be removed through the heat exchanger by the enclosure structure. The upper cover is fixed to the upper portion of the sidewalls.

[0035] The side cover is located parallel to the side wall of the electrolytic cell and, together with the upper cover and bottom plate, forms an enclosed space. Heat previously removed by natural convection is now trapped by the surrounding structure and removed through the heat exchanger. The side cover has a viewing hole for the thermal imager and holes for support rods. The side cover is removable and can be easily removed, installed, and positioned using support rods 8. Handles are welded to the side cover for easy installation and removal.

[0036] The bottom plate is located at the bottom edge of the electrolytic cell's side walls, and together with the side and upper covers, forms a closed space. This allows the heat that was originally carried away by natural convection to be removed through the heat exchanger through the shielding structure. The bottom plate is fixed to the upper part of the side walls.

[0037] The heat exchanger is composed of multiple heat exchange modules 5. Each module is made of a bent aluminum alloy tube or a pipe made of other materials. Different heat exchange modules are connected in parallel or in series through valves. Quick connectors are used to connect each module. By adjusting the connection method of different heat exchange modules, different heat exchange rates can be achieved. When all heat exchange modules are connected in series, the heat exchange rate is minimum, and when the heat exchange modules are connected in parallel, the heat exchange rate is maximum. In addition, the heat exchange rate can be further adjusted by adjusting the flow rate of the cooling medium in the heat exchanger, so that the amount of waste heat recovered from the side wall can be adjusted according to the size of the heat flow.

[0038] During normal production, maintenance workers regularly check the temperature of the sidewalls, primarily through visual inspection. If a bright red color appears locally, it indicates that the cathode at that location has worn out, which is actually too late. For this reason, a thermal imager 6 and an alarm are also provided in this system. The thermal imager is located at the lower part of the upper cover plate and the upper part of the sidewall plate to monitor the temperature distribution of the sidewalls to prevent local sidewall temperatures from being too high. When the monitored temperature exceeds the set threshold, the alarm sounds an alarm. Specifically, the thermal imager uses a host computer and multiple cameras, which can be switched between each other to ensure effective monitoring.

[0039] The system also includes a partition 7, located between the electrolytic cell sidewall and the heat exchanger. The partition is formed of two or more layers and has holes or slits. By moving the different layers of partitions, the visible area between the heat exchanger and the sidewall can be adjusted to adjust the heat exchange rate. The system also includes support rods, one side of which is fixed to the electrolytic cell sidewall. These rods are primarily used to support and secure the heat exchanger and side cover. Each heat exchange module has at least four support rods.

[0040] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made based on the essence of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. An active electrolytic cell side wall waste heat recovery system, characterized in that: include: The electrolytic cell, whose side walls are divided into several heat exchange module installation area units, is the space for electrolytic aluminum production; The upper cover plate is located outside the upper edge of the side wall of the electrolytic cell and forms a relatively closed space with the side cover plate and the bottom plate to improve the heat exchange efficiency; The side cover plate is located on the side of the electrolytic cell side wall, parallel to the side wall, and forms a relatively closed space with the upper cover plate and the bottom plate to improve the heat exchange efficiency; the side cover plate has a thermal imager observation hole and a support rod hole; The bottom plate is located at the lower edge of the side wall of the electrolytic cell and forms a relatively closed space with the side cover plate and the upper cover plate for active recovery of waste heat; A heat exchanger, which is composed of a plurality of heat exchange modules, which are respectively installed in the plurality of heat exchange module installation area units; Also includes: Thermal imager, used to monitor the temperature of the electrolytic cell sidewall to ensure safe operation of the system; A partition is located between the side wall of the electrolytic cell and the heat exchanger; the partition has holes or gaps and is composed of two or more layers, so that the visible area between the heat exchanger and the side wall can be changed by moving different layers of partitions to adjust the heat exchange capacity of the heat exchanger; Support rods, used to support and position the heat exchanger and side covers; Different heat exchange modules are connected in parallel or in series through valve combinations; by adjusting the connection mode of different heat exchange modules, different heat exchange capacities can be achieved.

2. The active electrolytic cell side wall waste heat recovery system according to claim 1, characterized in that: The heat exchange amount is further adjusted by adjusting the flow rate of the cooling medium in the heat exchanger to ensure the heat exchange amount that needs to be extracted.

3. The active electrolytic cell side wall waste heat recovery system according to claim 1, characterized in that: A handle is provided on the side cover plate.

4. The active electrolytic cell side wall waste heat recovery system according to claim 1, characterized in that: The thermal imager is operated in the form of a host computer and multiple cameras, and the cameras can be switched with each other.

5. The active electrolytic cell side wall waste heat recovery system according to claim 4, characterized in that: Also includes: An alarm is configured to sound an alarm when the temperature detected by the thermal imager is higher than a set value.

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