Electrolytic cell waste heat recovery device and electrolytic cell

Abstract

The present invention relates to the technical field of electrolytic cell structures, and specifically relates to an electrolytic cell waste heat recovery device and an electrolytic cell. The electrolytic cell waste heat recovery device comprises a heat exchange medium pipeline, wherein cell wall heat exchangers are provided on the heat exchange medium pipeline, and cradle frame heat exchangers which correspond to the cell wall heat exchangers to form heat exchanger sets are further provided on the heat exchange medium pipeline; a cradle frame heat exchanger and a cell wall heat exchanger in the same heat exchanger set are arranged in series, and the cradle frame heat exchanger is located upstream of the cell wall heat exchanger. Heat exchange medium is preheated via the temperature of a cradle frame; after the temperature of the heat exchange medium is increased, said heat exchange medium enters the cell wall heat exchanger for secondary heat exchange, thereby preventing low-temperature heat exchange medium from directly exchanging heat with a side wall of a cell casing and causing an impact on the temperature of said side wall, and thus preventing the melt electrolysis temperature in the electrolytic cell from being easily affected.

Description

Electrolytic cell waste heat recovery device and electrolytic cell Technical Field

[0001] The present invention relates to the technical field of electrolytic cell structures, and in particular to an electrolytic cell waste heat recovery device and an electrolytic cell. Background Art

[0002] An aluminum reduction cell consists of a cell shell and U-shaped cradles, which are arranged in multiple groups along the length of the cell. The cell shell rests on these cradles, which are spaced apart. The cradles are topped with a trough edge plate, and the bottom of the cell shell is fitted with cathode steel bars. The cell shell sidewalls have sections that protrude between adjacent cradles. During the aluminum electrolytic production process, the cell sidewalls reach temperatures of 300°C to 400°C. This high heat source temperature makes them highly recyclable.

[0003] A Chinese utility model patent with authorization announcement number CN213142224U and authorization announcement date of May 7, 2021 discloses a waste heat recovery system for an aluminum electrolytic cell, which is used for recovering waste heat from the side wall of the aluminum electrolytic cell. The system includes a tank wall heat exchanger, a circulation pump station and a secondary heat exchanger. Multiple groups of tank wall heat exchangers are arranged on the side wall of the tank shell of the aluminum electrolytic cell. The outlet end of the circulation pump station is connected to the liquid inlet end of the tank wall heat exchanger through a first delivery main pipe and a first delivery branch pipe; the liquid outlet end of the tank wall heat exchanger is connected to the liquid inlet end of the secondary heat exchanger through a second delivery branch pipe and a second delivery main pipe. The circulation pump station and the secondary heat exchanger are connected through a circulation pipeline. Here, the heat exchange medium inlet of the liquid inlet end of the tank wall heat exchanger and the heat exchange medium outlet of the liquid outlet end of the tank wall heat exchanger; the heat exchange medium is transported to the tank wall heat exchanger through the first delivery main pipe and the first delivery branch pipe. After being heated by heat exchange, the heat is transported to the secondary heat exchanger by the second delivery branch pipe and the second delivery main pipe, and enters the circulation pump station through the circulation pipeline after being cooled by heat exchange. During the working process, the circulation pump station provides power, so that the heat exchange medium circulates through the circulation pump station, the first delivery main pipe, the first delivery branch pipe, the tank wall heat exchanger, the second delivery branch pipe, the second delivery main pipe, the secondary heat exchanger, the circulation pipeline, and the circulation pump station in sequence. The heat exchange medium exchanges heat and heats up in the tank wall heat exchanger, thereby realizing the waste heat recovery of the tank shell side wall of the aluminum electrolytic cell. When the heated heat exchange medium enters the secondary heat exchanger, secondary heat exchange is realized. At this time, the heat exchange medium is cooled after heat exchange, so that it is convenient for circulation. The heat exchanged can be directly used by users. For example, the high-temperature water generated by heat exchange can be used for heating or domestic water, and can also be used for other purposes according to the production chain.

[0004] However, since the temperature of the heat exchange medium becomes relatively low after releasing heat in the secondary heat exchanger, generally around 50°C, while the temperature of the side wall of the electrolytic cell shell reaches above 300°C, the temperature difference is relatively large. When the low-temperature heat exchange medium circulates to the cell wall heat exchanger, it has a greater impact on the temperature of the side wall of the cell shell, which is not conducive to controlling the electrolysis temperature of the melt in the electrolytic cell.

[0005] Summary of the Invention

[0006] The purpose of the present invention is to provide an electrolytic cell waste heat recovery device to solve the problem that the current electrolytic cell waste heat recovery device easily affects the electrolysis temperature of the melt in the electrolytic cell; the purpose of the present invention is also to provide an electrolytic cell to solve the above problem.

[0007] The technical solution of the electrolytic cell waste heat recovery device of the present invention is:

[0008] A device for recovering waste heat from an electrolytic cell comprises a heat exchange medium pipeline, a tank wall heat exchanger is provided on the heat exchange medium pipeline, the tank wall heat exchanger has a tank wall heat conducting portion for exchanging heat with the tank shell side wall of the electrolytic cell, a cradle heat exchanger corresponding to the tank wall heat exchanger and constituting a heat exchanger group is further provided on the heat exchange medium pipeline, the cradle heat exchanger and the tank wall heat exchanger in the same heat exchanger group are arranged in series, the cradle heat exchanger is located upstream of the tank wall heat exchanger, and the cradle heat exchanger has a cradle heat conducting portion for exchanging heat with the cradle side wall of the electrolytic cell.

[0009] Beneficial effect: By arranging the cradle heat exchanger and the tank wall heat exchanger to form a combination, the heat exchange medium first enters the cradle heat exchanger and exchanges heat with the cradle side wall. The temperature of the cradle side wall is lower than the temperature of the tank shell side wall, about 150℃~200℃. The heat exchange medium is preheated by using the temperature of the cradle. After the temperature of the heat exchange medium is increased, it enters the tank wall heat exchanger for heat exchange again, thus forming a secondary heat exchange, which not only reduces the temperature of the cradle, but also avoids the low-temperature heat exchange medium directly exchanging heat with the tank shell side wall and causing an impact on its temperature, thereby not easily affecting the electrolysis temperature of the melt in the electrolytic cell.

[0010] Furthermore, the cradle heat exchanger includes a heat-conducting contact surface for contacting with a vertical side wall of the cradle that is perpendicular to the side wall of the tank shell, and the heat-conducting contact surface constitutes the heat-conducting portion of the cradle.

[0011] Beneficial effects: The vertical side wall of the cradle perpendicular to the side wall of the tank shell has a larger area, which is convenient for arranging the cradle heat exchanger. Moreover, the vertical side wall of the cradle is adjacent to the side wall of the tank shell and has a higher temperature, which is convenient for improving the heat exchange efficiency and also convenient for pipeline arrangement.

[0012] Furthermore, a fastening connection structure for fixing to the vertical side wall is provided on the heat-conducting contact surface.

[0013] Beneficial effect: The tight connection ensures reliable thermal contact, which is conducive to reliable use.

[0014] Furthermore, the heat exchange medium inlet and the heat exchange medium outlet of the tank wall heat exchanger are higher than those of the cradle heat exchanger in the vertical direction.

[0015] Beneficial effects: It is convenient for piping arrangement and convenient for realizing series connection of the tank wall heat exchanger and the cradle frame heat exchanger.

[0016] Furthermore, the cradle heat exchanger includes a heat exchange coil, which is spirally wound from the periphery to the center, with a heat exchange medium inlet end of the heat exchange coil at the periphery and a heat exchange medium outlet end leading out from the center.

[0017] Beneficial effect: The heat exchange medium outlet can be arranged further away from the tank wall heat exchanger, which is convenient for pipeline layout.

[0018] Furthermore, the cradle heat exchanger includes a heat exchange coil and a coil mounting plate, and the coil mounting plate is provided with a coil mounting groove for embedding the heat exchange coil.

[0019] Beneficial effect: Installing the heat exchange coil in the coil installation groove is beneficial to increasing the heat exchange contact area.

[0020] Furthermore, flexible joints are provided on the pipelines between the cradle heat exchanger and the liquid inlet pipeline of the heat exchange medium pipeline, between the tank wall heat exchanger and the liquid outlet pipeline of the heat exchange medium pipeline, and between the tank wall heat exchanger and the cradle heat exchanger.

[0021] Beneficial effects: The circulation pipeline can be installed separately from the tank wall heat exchanger and the cradle frame heat exchanger by using a flexible joint, which is convenient for installation in a relatively narrow space around the electrolytic cell. At the same time, the main part of the circulation pipeline can be installed first, and then the tank wall heat exchanger can be installed, which is beneficial to shorten the dry burning time of the tank wall heat exchanger after installation, and also helps to reduce the thermal insulation effect of the heat exchanger on the electrolytic cell when it is not working after installation.

[0022] Furthermore, the heat exchange medium pipeline includes a main pipeline and a branch pipeline, the branch pipeline includes a hose, and the tank wall heat exchanger and the cradle heat exchanger are arranged on the branch pipeline.

[0023] Beneficial effect: The installation operation of the heat exchanger is facilitated by the combination of the hose and the flexible joint.

[0024] Furthermore, the heat exchange medium pipeline includes an inlet pipeline and an outlet pipeline. The inlet pipeline is used to connect to the cradle heat exchanger, and the outlet pipeline is used to connect to the tank wall heat exchanger. The inlet pipeline and the outlet pipeline are arranged in parallel up and down.

[0025] Beneficial effects: It is beneficial to reduce the width of the electrolytic cell, save space, and facilitate the installation of a high-temperature resistant protective cover above the pipeline.

[0026] The technical solution of the electrolyzer of the present invention is:

[0027] The electrolytic cell includes a cell shell, a cradle and an electrolytic cell waste heat recovery device. The electrolytic cell waste heat recovery device includes a heat exchange medium pipeline. A cell wall heat exchanger is provided on the heat exchange medium pipeline. The cell wall heat exchanger has a cell wall heat conduction portion for performing heat exchange with the side wall of the cell shell of the electrolytic cell. A cradle heat exchanger corresponding to the cell wall heat exchanger and constituting a heat exchanger group is also provided on the heat exchange medium pipeline. The cradle heat exchanger and the cell wall heat exchanger in the same heat exchanger group are arranged in series, and the cradle heat exchanger is located upstream of the cell wall heat exchanger. The cradle heat exchanger has a cradle heat conduction portion for performing heat exchange with the side wall of the cradle of the electrolytic cell.

[0028] Beneficial effect: By arranging the cradle heat exchanger and the tank wall heat exchanger to form a combination, the heat exchange medium first enters the cradle heat exchanger and exchanges heat with the cradle side wall. The temperature of the cradle side wall is lower than the temperature of the tank shell side wall, about 150℃~200℃. The heat exchange medium is preheated by using the temperature of the cradle. After the temperature of the heat exchange medium is increased, it enters the tank wall heat exchanger for heat exchange again, thus forming a secondary heat exchange, which not only reduces the temperature of the cradle, but also avoids the low-temperature heat exchange medium directly exchanging heat with the tank shell side wall and causing an impact on its temperature, thereby not easily affecting the electrolysis temperature of the melt in the electrolytic cell.

[0029] Furthermore, the cradle heat exchanger includes a heat-conducting contact surface for contacting with a vertical side wall of the cradle that is perpendicular to the side wall of the tank shell, and the heat-conducting contact surface constitutes the heat-conducting portion of the cradle.

[0030] Beneficial effects: The vertical side wall of the cradle perpendicular to the side wall of the tank shell has a larger area, which is convenient for arranging the cradle heat exchanger. Moreover, the vertical side wall of the cradle is adjacent to the side wall of the tank shell and has a higher temperature, which is convenient for improving the heat exchange efficiency and also convenient for pipeline arrangement.

[0031] Furthermore, a fastening connection structure for fixing to the vertical side wall is provided on the heat-conducting contact surface.

[0032] Beneficial effect: The tight connection ensures reliable thermal contact, which is conducive to reliable use.

[0033] Furthermore, the heat exchange medium inlet and the heat exchange medium outlet of the tank wall heat exchanger are higher than those of the cradle heat exchanger in the vertical direction.

[0034] Beneficial effects: It is convenient for piping arrangement and convenient for realizing series connection of the tank wall heat exchanger and the cradle frame heat exchanger.

[0035] Furthermore, the cradle heat exchanger includes a heat exchange coil, which is spirally wound from the periphery to the center, with a heat exchange medium inlet end of the heat exchange coil at the periphery and a heat exchange medium outlet end leading out from the center.

[0036] Beneficial effect: The heat exchange medium outlet can be arranged further away from the tank wall heat exchanger, which is convenient for pipeline layout.

[0037] Furthermore, the cradle heat exchanger includes a heat exchange coil and a coil mounting plate, and the coil mounting plate is provided with a coil mounting groove for embedding the heat exchange coil.

[0038] Beneficial effect: Installing the heat exchange coil in the coil installation groove is beneficial to increasing the heat exchange contact area.

[0039] Furthermore, flexible joints are provided on the pipelines between the cradle heat exchanger and the liquid inlet pipeline of the heat exchange medium pipeline, between the tank wall heat exchanger and the liquid outlet pipeline of the heat exchange medium pipeline, and between the tank wall heat exchanger and the cradle heat exchanger.

[0040] Beneficial effects: The circulation pipeline can be installed separately from the tank wall heat exchanger and the cradle frame heat exchanger by using a flexible joint, which is convenient for installation in a relatively narrow space around the electrolytic cell. At the same time, the main part of the circulation pipeline can be installed first, and then the tank wall heat exchanger can be installed, which is beneficial to shorten the dry burning time of the tank wall heat exchanger after installation, and also helps to reduce the thermal insulation effect of the heat exchanger on the electrolytic cell when it is not working after installation.

[0041] Furthermore, the heat exchange medium pipeline includes a main pipeline and a branch pipeline, the branch pipeline includes a hose, and the tank wall heat exchanger and the cradle heat exchanger are arranged on the branch pipeline.

[0042] Beneficial effect: The installation operation of the heat exchanger is facilitated by the combination of the hose and the flexible joint.

[0043] Furthermore, the heat exchange medium pipeline includes an inlet pipeline and an outlet pipeline. The inlet pipeline is used to connect to the cradle heat exchanger, and the outlet pipeline is used to connect to the tank wall heat exchanger. The inlet pipeline and the outlet pipeline are arranged in parallel up and down.

[0044] Beneficial effects: It is beneficial to reduce the width of the electrolytic cell, save space, and facilitate the installation of a high-temperature resistant protective cover above the pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] FIG1 is a schematic diagram of the partial structure of the tank shell, cradle, tank edge plate, and cathode steel rod in Example 1 of the electrolytic cell of the present invention;

[0046] FIG2 is a schematic diagram of the AA section of FIG1 ;

[0047] FIG3 is a schematic diagram of FIG1 with an electrolytic cell waste heat recovery device added;

[0048] FIG4 is a schematic diagram of a BB cross-section of FIG3 ;

[0049] FIG5 is a schematic structural diagram of the tank wall heat exchanger in FIG3;

[0050] FIG6 is a schematic cross-sectional view of the cradle heat exchanger in FIG3 ;

[0051] FIG7 is a schematic structural diagram of the second heat exchange tube in FIG6 ;

[0052] FIG8 is a schematic structural diagram of the inner plate in FIG6 .

[0053] In the figure: 1. tank shell; 11. tank shell side wall; 2. cradle; 21. rib plate; 22. vertical side wall; 3. cathode steel rod; 4. tank edge plate; 5. tank wall heat exchanger; 51. first inlet; 52. first outlet; 53. first bolt through-hole; 54. first thermocouple fixing bracket; 6. cradle heat exchanger; 61. second inlet; 62. second outlet; 63. second bolt through-hole; 64. second heat exchange tube; 65. second inner plate; 66. second insulation layer; 67. second outer plate; 68. second coil mounting groove; 7. low-temperature main line; 8. high-temperature main line; 9. first branch pipe; 10. second branch pipe; 101. first hose; 102. second hose; 103. third hose. DETAILED DESCRIPTION

[0054] Example 1 of the electrolytic cell of the present invention:

[0055] In this embodiment, a cradle heat exchanger is provided in conjunction with a tank wall heat exchanger, so that the heat exchange medium first enters the cradle heat exchanger to exchange heat with the cradle side wall. The temperature of the cradle side wall is lower than that of the tank shell side wall, about 150°C to 200°C. The heat exchange medium is preheated by utilizing the temperature of the cradle. After the temperature of the heat exchange medium is increased, it enters the tank wall heat exchanger for further heat exchange, thus forming a secondary heat exchange, avoiding the low-temperature heat exchange medium from directly exchanging heat with the tank shell side wall and causing an impact on its temperature, thereby not easily affecting the electrolysis temperature of the melt in the electrolytic cell.

[0056] As shown in Figures 1-8, the electrolytic cell comprises a cell shell 1, a cradle 2, and an electrolytic cell waste heat recovery device. Multiple cradles 2 are provided, spaced apart along the length of the electrolytic cell. Each cradle 2 has a U-shaped structure, comprising two opposing arms along the width of the electrolytic cell and a connecting arm connecting the two arms. The cell shell 1 is mounted between the two arms and supported on the connecting arm. The cell shell sidewall 11 emerges from between the side arms on the same side of two adjacent cradles 2. A trough edge plate 4 is provided at the top of the cradle 2, facing upward. A cathode steel bar assembly is provided at the bottom of the cell shell 1. Each cathode steel bar assembly comprises two cathode steel bars 3 and is located between two adjacent cradles 2. The side arms on the same side of each pair of adjacent cradles 2, along with the corresponding cell shell sidewall 11, the trough edge plate 4 at the top of the cradle 2, and the cathode steel bar assembly exposed at the bottom of the electrolytic cell, form a cavity. This creates multiple cavities along the length of the electrolytic cell. Figure 1 shows the structure of one of the cavity positions, that is, the structure in which two adjacent cradles 2 are located between the side arms on the same side; Figure 2 shows a partial view of the positional relationship of the side arms of one of the cradles 2 relative to the tank shell 1 as viewed from the length direction of the electrolytic cell. The cradle 2 is welded from profiles, and the side arms of the cradle 2 include vertical plates perpendicular to the side walls 11 of the tank shell and horizontally arranged ribs 21 fixed on the vertical plates. Several ribs 21 are provided in the up and down directions, and the vertical plates constitute vertical side walls 22.

[0057] The electrolytic cell waste heat recovery device includes a heat exchange medium pipeline and a heat exchanger group installed in each cavity. Each heat exchanger group is connected in parallel to the heat exchange medium pipeline. The heat exchanger group includes a tank wall heat exchanger 5 and a cradle heat exchanger 6 arranged in series. The cradle heat exchanger 6 is located upstream of the tank wall heat exchanger 5, so that the heat exchange medium in the heat exchange medium pipeline enters the cradle heat exchanger 6 for preheating before entering the tank wall heat exchanger 5. The tank wall heat exchanger 5 is mounted on the tank shell sidewall 11, and the cradle heat exchanger 6 is mounted on the vertical sidewall 22 of the cradle 2 and located between the upper and lower ribs 21.

[0058] The heat exchange medium pipeline includes a main pipeline and branch pipelines. The main pipeline includes a low-temperature main line 7 and a high-temperature main line 8. There are multiple groups of branch pipelines, each corresponding to a group of branch pipelines for each heat exchanger group. Each heat exchanger group is connected to the low-temperature main line 7 and the high-temperature main line 8 through its corresponding branch pipeline. The low-temperature main line 7 constitutes the liquid inlet pipeline, and the high-temperature main line 8 constitutes the liquid outlet pipeline. The branch pipeline includes a first branch pipe 9 and a second branch pipe 10. The heat exchanger group is connected between the first branch pipe 9 and the second branch pipe 10.

[0059] The cradle heat exchanger 6 includes a second inner plate 65, a second heat exchange tube 64, a second insulation layer 66, and a second outer plate 67. The two ends of the second heat exchange tube 64 form a second inlet 61 and a second outlet 62, respectively. The branch pipeline also includes a first hose 101 connecting the second inlet 61 and the first branch pipe 9. The first hose 101 is connected to the first branch pipe 9 via a flexible joint. The second heat exchange tube 64 is a heat exchange coil, which is spirally wound from the periphery to the center. The heat exchange medium inlet end of the heat exchange coil is at the periphery and the heat exchange medium outlet end is drawn out from the center. The end where the second inlet 61 of the second heat exchange tube 64 is located is the heat exchange medium inlet end of the cradle heat exchanger 6, and the end where the second outlet 62 of the second heat exchange tube 64 is located is the heat exchange medium outlet end of the cradle heat exchanger 6. The second inlet 61 and the second outlet 62 are both located at the upper portion of the cradle heat exchanger 6 to facilitate pipeline connection.

[0060] The second inner plate 65 is used to be abutted against the vertical side wall 22 of the cradle 2. The plate surface of the inner plate abutting the vertical side wall 22 constitutes a heat-conducting contact surface. The heat-conducting contact surface constitutes a heat-conducting portion of the cradle for heat exchange with the cradle side wall of the electrolytic cell. The vertical side wall 22 of the cradle 2 in the length direction of the electrolytic cell has a large area, which is convenient for arranging the cradle heat exchanger 6. Moreover, the vertical side wall 22 of the cradle 2 is adjacent to the tank shell side wall 11 and has a higher temperature, which is convenient for improving the heat exchange efficiency and also convenient for pipeline arrangement.

[0061] A second coil mounting groove 68 is provided on the surface of the second inner plate 65 facing away from the vertical sidewall 22. The extension direction and cross-sectional shape of the second coil mounting groove 68 are adapted to the second heat exchange tube 64. The second inner plate 65 constitutes a coil mounting plate, and the second heat exchange tube 64 can be completely embedded in the second coil mounting groove 68, which helps to increase the heat exchange contact area. The second outer plate 67 is formed by stamping or welding a thin metal plate and has an inner cavity with an opening facing the second inner plate 65. A second thermal insulation layer 66 is installed in the inner cavity of the second outer plate 67 to insulate the second heat exchange tube 64.

[0062] The second inner plate 65 and the second outer plate 67 are provided with corresponding second bolt holes 63. Fixing bolts are welded to the vertical sidewalls 22. When installing the cradle heat exchanger 6, the fixing bolts are passed through the second bolt holes 63 and secured with nuts. The second bolt holes 63 on the second inner plate 65 form a fastening connection structure for securing the heat transfer surface to the vertical sidewalls 22. The bolt and nut fastening ensures reliable heat transfer contact, facilitating reliable operation.

[0063] The tank wall heat exchanger 5 is vertically taller than the cradle heat exchanger 6. The components of the tank wall heat exchanger 5 are essentially the same as those of the cradle heat exchanger 6. The tank wall heat exchanger 5 includes a first inner plate, a first heat exchange tube, a first insulation layer, and a first outer plate. The two end openings of the first heat exchange tube respectively constitute a first inlet 51 and a first outlet 52, which respectively constitute the heat exchange medium inlet and outlet of the tank wall heat exchanger. The branch pipeline also includes a second hose 102 connecting the first inlet 51 and the second outlet 62, and a third hose 103 connecting the first outlet 52 and the second branch pipe 10. The second hose 102 is connected to the second outlet 62 via a flexible joint, and the third hose 103 is connected to the second branch pipe 10 via a flexible joint. The second heat exchange tube 64 is a heat exchange coil. The first heat exchange tube and the second heat exchange tube 64 have different coiling forms. The first heat exchange tube is U-shaped coiling. The first inlet 51 and the first outlet 52 of the first heat exchange tube are respectively located at the two corners of the first heat exchange tube. The first inlet 51 and the first outlet 52 are both located at the upper part of the tank wall heat exchanger 5 to facilitate pipeline connection.

[0064] The inner surface of the first inner plate forms the thermal contact surface of the tank wall heat exchanger 5 with the tank shell sidewall 11. The thermal contact surface of the tank wall heat exchanger 5 constitutes the tank wall heat conduction portion for heat exchange with the tank shell sidewall 11 of the electrolytic cell. The outer surface of the first inner plate is provided with a mounting groove for the first heat exchange tube. Corresponding first bolt holes 53 are provided on the first inner plate and the first outer plate. Fixing bolts are welded to the tank shell sidewall 11. When installing the tank wall heat exchanger 5, the fixing bolts are passed through the first bolt holes 53 and then secured with nuts. The first bolt holes 53 on the first inner plate form the fixed connection structure of the tank wall heat exchanger 5 for fixing to the outer wall surface of the tank shell sidewall 11. The tank wall heat exchanger 5 is also provided with a first thermocouple fixing bracket 54 to facilitate the installation of a thermocouple to monitor the temperature of the tank shell sidewall 11.

[0065] The first, second, and third hoses 101, 102, and 103 are all metal hoses, with the ends of the hoses without unions welded to the corresponding connecting components. Branch valves are installed at the junction of the main pipeline with the branch pipelines. These valves can be installed on the first and second branch pipes 9, 10 to prevent dust from entering the main pipeline during installation. The heat exchange medium pipeline is a circulating pipeline equipped with a thermal insulation layer and a high-temperature protective cover above it.

[0066] Before installing the heat exchanger, use a bolt welder to secure the bolts to the corresponding mounting locations on the tank shell sidewalls 11 and vertical sidewalls 22, according to the bolt hole locations. The insulation layer is made of a high-temperature, flame-retardant material such as silicate wool. The inner and outer panels can be riveted, bolted, or welded. The inner panels of the tank wall heat exchanger 5 and cradle frame heat exchanger 6 are made of highly thermally conductive materials such as aluminum or copper, while the outer panels are made of non-magnetic materials such as stainless steel.

[0067] Because the sides of aluminum electrolytic cells require a complex busbar system around the cell, space is limited and insulation requirements are high, making the installation sequence and safe operation of the heat exchanger particularly important. Before installation, the busbars and cathode steel bars surrounding the operating area should be covered with high-temperature insulating rubber to prevent short circuits between tools and the heat exchanger during operation. The heat exchanger mounting locations on the cell shell sidewalls and the vertical sidewalls of the cradle should be cleaned with a polisher to remove dust and protrusions. The main pipe brackets should be bolted to the steel support frame outside the cradle. The heat exchanger mounting locations on the cell shell sidewalls and cradle should be welded with bolts. The high- and low-temperature main pipes should be installed first, followed by the heat exchanger. Installing the main pipes first is important because the cell wall temperature is higher. This reduces the dry-burning time of the cell wall heat exchanger after installation. Furthermore, the heat exchanger insulates the cell when not in operation. Overtime, this can cause the melt temperature in the cell to rise, melting the sidewalls and impacting cell production. In this embodiment, the provision of flexible joints allows the pipelines and heat exchangers to be installed separately. The low-temperature and high-temperature main lines are installed on the main line brackets surrounding the electrolytic cell. When installing the main lines, the branch valves should be closed first to prevent dust from entering the main lines. After installing the main lines, first install the deep tank wall heat exchanger, then install the cradle heat exchanger. Use metal hoses to connect the heat exchangers to each other and to the high and low temperature main lines. On the high and low temperature main lines, on the metal hoses, and on the outside of the heat exchanger, a heat insulation layer is provided. A high-temperature resistant protective cover is provided above the heat insulation layer of the high and low temperature main lines to prevent the electrolyte from dripping when replacing the anode.

[0068] The low-temperature heat exchange medium in the low-temperature main line, at a temperature of 50°C to 70°C, flows through the corresponding pipelines via the second inlet into the cradle heat exchanger. It undergoes a first stage of heat exchange through the cradle heat exchanger's internal heat exchange structure and the 150°C to 200°C vertical sidewalls of the cradle. After the first stage of heat exchange, the heat exchange medium is heated to 70°C to 90°C before passing through the corresponding hoses through the first inlet into the tank wall heat exchanger. It undergoes a second stage of heat exchange through the tank wall heat exchanger's internal heat exchange structure and the 300°C to 400°C tank shell sidewalls. After heat exchange, the temperature rises to 150°C to 170°C. The high-temperature heat exchange medium then enters the high-temperature main line through the corresponding pipelines and is transported out for heating or power generation applications.

[0069] By installing a two-stage heat exchanger, with hoses and unions connecting both the two stages and the main pipeline, this system ensures convenient and quick installation in the tight spaces surrounding the electrolytic cell. The secondary heat exchange structure, located on the cradle and shell sidewalls of the aluminum electrolytic cell, can increase waste heat utilization by 10% to 40%, raising the heat exchange medium temperature by 10°C to 30°C compared to existing technologies, significantly improving the quality of the heat source. Its rational structural design enables high-value recovery of waste heat from aluminum electrolytic cells, making it easier to promote and apply.

[0070] Example 2 of the electrolytic cell of the present invention:

[0071] This embodiment provides a different cradle heat exchanger configuration than that of Example 1. The difference between this embodiment and Example 1 lies in that the cradle heat exchanger in Example 1 includes a thermally conductive contact surface for contacting the vertical sidewalls of the cradle along the length of the electrolytic cell. In this embodiment, the cradle has an outer wall facing away from the cell shell sidewall, and the cradle heat exchanger has a thermally conductive contact surface for contacting the outer wall of the cradle.

[0072] Example 3 of the electrolytic cell of the present invention:

[0073] This embodiment provides a different arrangement of heat-conducting contact surfaces than that of Example 1. The difference between this embodiment and Example 1 lies in that, whereas the heat-conducting contact surface in Example 1 is provided with a fastening structure for securing it to the vertical sidewall, this embodiment does not have a fastening structure. Instead, the cradle frame is provided with a lug, and the outer panel of the cradle frame heat exchanger is provided with a fixing lug, which is fixed to the lug by bolts.

[0074] Example 4 of the electrolytic cell of the present invention:

[0075] This embodiment provides a different heat exchanger assembly arrangement from that of Example 1. The difference between this embodiment and Example 1 is that the tank wall heat exchanger in Example 1 is vertically higher than the cradle heat exchanger. In this embodiment, the upper end of the tank wall heat exchanger is flush with the upper end of the cradle heat exchanger.

[0076] Example 5 of the electrolytic cell of the present invention:

[0077] This embodiment provides a different cradle heat exchanger configuration than that of Example 1. The difference between this embodiment and Example 1 lies in that the cradle heat exchanger in Example 1 includes a heat exchange coil that is spirally wound from the periphery toward the center, with the heat exchange medium inlet end of the heat exchange coil located at the periphery and the heat exchange medium outlet end extending from the center. In contrast, the heat exchange coil of the cradle heat exchanger in this embodiment is coiled in a U-shape.

[0078] Example 6 of the electrolytic cell of the present invention:

[0079] This embodiment provides a different cradle heat exchanger configuration from that of Example 1. The difference between this embodiment and Example 1 lies in that the cradle heat exchanger in Example 1 includes a heat exchange coil and a coil mounting plate, which has a coil mounting groove for the heat exchange coil to be inserted into. In contrast, the heat exchange coil of this embodiment is sandwiched between an inner plate and an outer plate.

[0080] Example 7 of the electrolytic cell of the present invention:

[0081] This embodiment provides a different arrangement of the electrolytic cell waste heat recovery device from that of Example 1. The difference between this embodiment and Example 1 is that the first hose in Example 1 is connected to the main line via a flexible joint. In this embodiment, the first hose is connected to the main line by welding.

[0082] Example 8 of the electrolytic cell of the present invention:

[0083] This embodiment provides a branch pipeline arrangement different from that of embodiment 1. The difference between this embodiment and embodiment 1 is that the branch pipelines in embodiment 1 include soft pipes, while in this embodiment, the branch pipelines all use hard pipes.

[0084] Example 9 of the electrolytic cell of the present invention:

[0085] This embodiment provides a different arrangement of the tank wall heat exchanger from that of Example 1. The difference between this embodiment and Example 1 is that the tank wall heat exchanger in Example 1 is arranged on the outside of the tank shell side wall. In this embodiment, the tank wall heat exchanger is arranged on the inside of the tank shell side wall.

[0086] Example 10 of the electrolytic cell of the present invention:

[0087] This embodiment provides a different arrangement of heat exchange medium pipelines from that of Example 1. The difference between this embodiment and Example 1 is that the inlet and outlet pipelines in Example 1 are arranged in parallel vertically. In this embodiment, the inlet and outlet pipelines are arranged in parallel across the width of the electrolytic cell.

[0088] Embodiments of the electrolytic cell waste heat recovery device of the present invention:

[0089] The electrolytic cell waste heat recovery device in this embodiment is the same as the electrolytic cell waste heat recovery device in any of the above-mentioned electrolytic cell embodiments 1-10, and will not be described in detail here.

[0090] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments without inventive effort, or replace some of the technical features therein with equivalents. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. An electrolytic cell waste heat recovery device, comprising a heat exchange medium pipeline, a tank wall heat exchanger is arranged on the heat exchange medium pipeline, the tank wall heat exchanger has a tank wall heat conduction part for heat exchange with the tank shell side wall of the electrolytic cell, characterized in that: A cradle heat exchanger is also provided on the heat exchange medium pipeline, corresponding to the tank wall heat exchanger and constituting a heat exchanger group. The cradle heat exchanger and the tank wall heat exchanger in the same heat exchanger group are arranged in series and the cradle heat exchanger is located upstream of the tank wall heat exchanger. The cradle heat exchanger has a cradle heat conducting part for exchanging heat with the cradle side wall of the electrolytic cell.

2. The electrolytic cell waste heat recovery device according to claim 1 is characterized in that: The cradle heat exchanger comprises a heat-conducting contact surface for contacting with a vertical side wall of the cradle perpendicular to the side wall of the tank shell, and the heat-conducting contact surface constitutes a heat-conducting portion of the cradle.

3. The electrolytic cell waste heat recovery device according to claim 2 is characterized in that: A fastening connection structure for fixing with the vertical side wall is provided on the heat-conducting contact surface.

4. The electrolytic cell waste heat recovery device according to claim 1, 2 or 3, characterized in that: The heat exchange medium inlet and the heat exchange medium outlet of the tank wall heat exchanger are higher than those of the cradle frame heat exchanger in the vertical direction.

5. The electrolytic cell waste heat recovery device according to claim 1, 2 or 3, characterized in that: The cradle heat exchanger comprises a heat exchange coil which is spirally wound from the periphery to the center, a heat exchange medium inlet end of the heat exchange coil is at the periphery and a heat exchange medium outlet end is led out from the center.

6. The electrolytic cell waste heat recovery device according to claim 1, 2 or 3, characterized in that: The cradle heat exchanger comprises a heat exchange coil and a coil mounting plate, and the coil mounting plate is provided with a coil mounting groove for embedding the heat exchange coil.

7. The electrolytic cell waste heat recovery device according to claim 1, 2 or 3, characterized in that: Flexible joints are respectively arranged on the pipelines between the cradle heat exchanger and the liquid inlet pipeline of the heat exchange medium pipeline, between the tank wall heat exchanger and the liquid outlet pipeline of the heat exchange medium pipeline, and between the tank wall heat exchanger and the cradle heat exchanger.

8. The electrolytic cell waste heat recovery device according to claim 7, characterized in that: The heat exchange medium pipeline comprises a main pipeline and a branch pipeline, the branch pipeline comprises a hose, and the tank wall heat exchanger and the cradle frame heat exchanger are arranged on the branch pipeline.

9. The electrolytic cell waste heat recovery device according to claim 1, 2 or 3, characterized in that: The heat exchange medium pipeline includes an inlet pipeline and an outlet pipeline. The inlet pipeline is used to connect with the cradle heat exchanger, and the outlet pipeline is used to connect with the tank wall heat exchanger. The inlet pipeline and the outlet pipeline are arranged in parallel up and down.

10. An electrolytic cell, comprising a cell shell, a cradle frame and an electrolytic cell waste heat recovery device, characterized in that: The electrolytic cell waste heat recovery device is the electrolytic cell waste heat recovery device as described in any one of claims 1 to 9 above.

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