WO2024255703A1 - Electrolytic cell waste heat recovery device and electrolytic cell - Google Patents

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

The 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

The aluminum electrolytic cell includes a cell shell and a U-shaped cradle frame. There are multiple groups of cradle frames arranged at intervals along the length of the electrolytic cell. The cell shell is placed on the multiple groups of cradle frames arranged at intervals. The top of the cradle frame is provided with a slot edge plate, the bottom of the cell shell is provided with a cathode steel bar, and the side wall of the cell shell has a portion exposed between two adjacent cradle frames. During the electrolytic aluminum production process, the temperature of the side wall of the aluminum electrolytic cell reaches 300℃～400℃, the heat source temperature is high, and it has a large recycling value.

A Chinese utility model patent with authorization announcement number CN213142224U and authorization announcement date May 7, 2021 discloses a waste heat recovery system for an aluminum electrolytic cell, which is used for waste heat recovery of the side wall of the aluminum electrolytic cell, and includes a cell wall heat exchanger, a circulating pump station and a secondary heat exchanger. Multiple groups of cell wall heat exchangers are arranged on the side wall of the cell shell of the aluminum electrolytic cell. The outlet end of the circulating pump station is connected to the liquid inlet end of the cell wall heat exchanger through a first delivery trunk pipe and a first delivery branch pipe; the liquid outlet end of the cell 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 trunk pipe, and the circulating pump station is connected to the secondary heat exchanger through a circulating pipeline. The heat exchange medium inlet at the liquid inlet end of the cell wall heat exchanger and the heat exchange medium outlet at the liquid outlet end of the cell wall heat exchanger; the heat exchange medium is transported to the cell wall heat exchanger through the first delivery trunk pipe and the first delivery branch pipe. After being heated by heat exchange, it is transported to the secondary heat exchanger by the second delivery branch pipe and the second delivery trunk 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 trunk pipe, the first delivery branch pipe, the tank wall heat exchanger, the second delivery branch pipe, the second delivery trunk 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 as to facilitate 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.

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.

Summary of the invention

The object 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 object of the present invention is also to provide an electrolytic cell to solve the above question.

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

A waste heat recovery device for an electrolytic cell comprises 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 exchanging heat with the tank shell side wall of the electrolytic cell, and a cradle heat exchanger corresponding to the tank wall heat exchanger and constituting a heat exchanger group is also arranged 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 and the cradle heat exchanger is located upstream of the tank wall heat exchanger, and the cradle heat exchanger has a cradle heat conduction part for exchanging heat with the cradle side wall of the electrolytic cell.

Beneficial effect: By arranging the cradle heat exchanger and the tank wall heat exchanger to form a match, the heat exchange medium first enters the cradle heat exchanger to exchange heat with the side wall of the cradle. 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 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 side wall of the tank shell and causing an impact on its temperature, thereby not easily affecting the electrolysis temperature of the melt in the electrolytic cell.

Furthermore, 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.

Beneficial effects: The vertical side wall of the cradle frame perpendicular to the side wall of the tank shell has a larger area, which is convenient for arranging the cradle frame heat exchanger. Moreover, the vertical side wall of the cradle frame 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 facilitating the layout of pipelines.

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

Beneficial effect: Reliable thermal contact is ensured by tightening the connection, which is conducive to reliable use.

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 frame heat exchanger in the vertical direction.

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

Furthermore, the cradle heat exchanger comprises a heat exchange coil, which is spirally wound from the periphery to the center, and the heat exchange medium inlet end of the heat exchange coil is at the periphery and the heat exchange medium outlet end is led out from the center.

Beneficial effect: The outlet end of the heat exchange medium can be arranged farther away from the tank wall heat exchanger, which is convenient for pipeline layout.

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 the heat exchange coil to be embedded.

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

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.

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 beneficial to reduce the heat insulation effect of the heat exchanger on the electrolytic cell when it is not working after installation.

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 frame heat exchanger are arranged on the branch pipeline.

Beneficial effect: The installation and operation of the heat exchanger are facilitated by using a hose in conjunction with a flexible joint.

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, and the inlet pipeline and the outlet pipeline are arranged in parallel up and down.

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.

The technical solution of the electrolytic cell of the present invention is:

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 exchanging heat with the cell shell side wall 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 exchanging heat with the cradle side wall of the electrolytic cell.

Beneficial effect: By arranging the cradle heat exchanger and the tank wall heat exchanger to form a match, the heat exchange medium first enters the cradle heat exchanger to exchange heat with the side wall of the cradle. 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 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 side wall of the tank shell and causing an impact on its temperature, thereby not easily affecting the electrolysis temperature of the melt in the electrolytic cell.

Furthermore, 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.

Beneficial effects: The vertical side wall of the cradle frame perpendicular to the side wall of the tank shell has a larger area, which is convenient for arranging the cradle frame heat exchanger. Moreover, the vertical side wall of the cradle frame 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 facilitating the layout of pipelines.

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

Beneficial effect: Reliable thermal contact is ensured by tightening the connection, which is conducive to reliable use.

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

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

Furthermore, the cradle heat exchanger comprises a heat exchange coil, which is spirally wound from the periphery to the center, and the heat exchange medium inlet end of the heat exchange coil is at the periphery and the heat exchange medium outlet end is led out from the center.

Beneficial effect: The outlet end of the heat exchange medium can be arranged farther away from the tank wall heat exchanger, which is convenient for pipeline layout.

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 the heat exchange coil to be embedded.

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

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.

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 beneficial to reduce the heat insulation effect of the heat exchanger on the electrolytic cell when it is not working after installation.

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 frame heat exchanger are arranged on the branch pipeline.

Beneficial effect: The installation and operation of the heat exchanger are facilitated by using a hose in conjunction with a flexible joint.

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, and the inlet pipeline and the outlet pipeline are arranged in parallel up and down.

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

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

Fig. 2 is a schematic diagram of the A-A cross section of Fig. 1;

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

Fig. 4 is a schematic cross-sectional view taken along line B-B of Fig. 3;

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

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

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

FIG. 8 is a schematic structural diagram of the inner plate in FIG. 6 .

In the figure: 1, tank shell; 11, tank shell side wall; 2, cradle frame; 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 frame; 6, cradle frame 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 installation 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

Embodiment 1 of electrolyzer of the present invention:

In this embodiment, a cradle heat exchanger is provided to cooperate with a tank wall heat exchanger so that the heat exchange medium first enters the cradle heat exchanger to exchange heat with the side wall of the cradle. The temperature of the side wall of the cradle is lower than that of the tank shell, about 150°C to 200°C. 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, avoiding the low-temperature heat exchange medium from directly exchanging heat with the side wall of the tank shell and causing an impact on its temperature, and thus not easily affecting the electrolysis temperature of the melt in the electrolytic cell.

As shown in Fig. 1-8, the electrolytic cell comprises a cell shell 1, a cradle frame 2 and an electrolytic cell waste heat recovery device. There are a plurality of cradle frames 2, each of which is arranged at intervals along the length direction of the electrolytic cell. The cradle frame 2 is a U-shaped structure, and the U-shaped cradle frame 2 comprises two side arms opposite to each other along the width direction of the electrolytic cell and a connecting arm connecting the two side arms. The cell shell 1 is installed between the two side arms and supported on the connecting arm, and the side wall 11 of the cell shell is exposed from between the side arms on the same side of two adjacent cradle frames 2. A slot edge plate 4 is provided on the top of the cradle frame 2, and the plate surface of the slot edge plate 4 faces upward. A cathode steel bar group is provided at the bottom of the cell shell 1, and each cathode steel bar group is located between two adjacent cradle frames 2, and the cathode steel bar group includes two cathode steel bars 3. The side arms on the same side of each two adjacent cradle frames 2 and the corresponding cell shell side wall 11, the slot edge plate 4 on the top of the cradle frame 2, and the cathode steel bar group exposed at the bottom of the electrolytic cell form a cavity, so that multiple cavities are formed in the length direction of the electrolytic cell. Figure 1 shows the structure of one of the cavity positions, that is, it shows the structure of two adjacent cradle frames 2 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 cradle frames 2 relative to the tank shell 1 observed from the length direction of the electrolytic cell. The cradle frame 2 is welded from profiles, and the side arms of the cradle frame 2 include a vertical plate perpendicular to the side wall 11 of the tank shell and a horizontally arranged rib plate 21 fixed on the vertical plate. A plurality of rib plates 21 are provided in the up and down directions, and the vertical plates constitute the vertical side walls 22.

The electrolytic cell waste heat recovery device includes a heat exchange medium pipeline and a heat exchanger group arranged 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 frame heat exchanger 6 arranged in series. The cradle frame 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 first enters the cradle frame heat exchanger 6 for preheating, and then enters the tank wall heat exchanger 5. The tank wall heat exchanger 5 is installed on the tank shell side wall 11, and the cradle frame heat exchanger 6 It is installed on the vertical side wall 22 of the cradle frame 2 and is located between the upper and lower ribs 21 .

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

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 end openings of the second heat exchange tube 64 respectively constitute a second inlet 61 and a second outlet 62. The branch pipeline also includes a first hose 101 connecting the second inlet 61 and the first branch pipe 9, and the first hose 101 is connected to the first branch pipe 9 through 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 led 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 part of the cradle heat exchanger 6, which is convenient for pipeline connection.

The second inner plate 65 is used to be abutted against the vertical side wall 22 of the cradle 2, and the plate surface of the inner plate abutting against the vertical side wall 22 constitutes a heat-conducting contact surface, and 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.

A second coil installation groove 68 is provided on the plate surface of the second inner plate 65 facing away from the vertical side wall 22. The extension direction and cross-sectional shape of the second coil installation groove 68 are adapted to the second heat exchange tube 64. The second inner plate 65 constitutes a coil installation plate. The second heat exchange tube 64 can be completely embedded in the second coil installation groove 68, which is conducive to increasing the heat exchange contact area. The second outer plate 67 is formed by stamping or welding a metal sheet. The second outer plate 67 has an inner cavity. The inner cavity of the second outer plate 67 has an opening and the opening faces the second inner plate 65. The second insulation layer 66 is installed in the inner cavity of the second outer plate 67. The second insulation layer 66 insulates the second heat exchange tube 64.

The second inner plate 65 and the second outer plate 67 are provided with corresponding second bolt holes 63, and the vertical side wall 22 is welded with fixing bolts. When installing the cradle heat exchanger 6, the fixing bolts are passed through the second bolt holes 63 and then fixed with nuts. The second bolt holes 63 on the second inner plate 65 constitute a fastening connection structure provided on the heat conduction contact surface for fixing with the vertical side wall 22. The fastening connection through bolts and nuts ensures reliable heat conduction contact, which is conducive to reliable use.

The tank wall heat exchanger 5 is higher than the cradle frame heat exchanger 6 in the vertical direction. The composition of the tank wall heat exchanger 5 is basically the same as that of the cradle frame heat exchanger 6. The tank wall heat exchanger 5 includes a first inner plate, a first heat exchange tube, a first insulation layer, a first outer The first heat exchange tube 64 is a heat exchange coil. The first heat exchange tube 64 has different winding forms. The first heat exchange tube 64 is a U-shaped winding form. 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 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 of the first heat exchange tube are both located at the upper part of the tank wall heat exchanger 5, which is convenient for pipeline connection.

The inner plate surface of the first inner plate constitutes the heat-conducting contact surface of the tank wall heat exchanger 5 that is attached to the tank shell side wall 11. The heat-conducting contact surface of the tank wall heat exchanger 5 constitutes the tank wall heat-conducting part for heat exchange with the tank shell side wall 11 of the electrolytic tank. The outer plate surface of the first inner plate is provided with an installation groove for the first heat exchange tube to be adapted and installed. The first inner plate and the first outer plate are provided with corresponding first bolt through holes 53. The tank shell side wall 11 is welded with fixing bolts. When installing the tank wall heat exchanger 5, the fixing bolts are passed through the first bolt through holes 53 and then fixed with nuts. The first bolt through holes 53 on the first inner plate constitute the fixed connection structure of the tank wall heat exchanger 5 for fixing with the outer wall surface of the tank shell side wall 11. The tank wall heat exchanger 5 is also provided with a first thermocouple fixing bracket 54 so as to install a thermocouple to monitor the temperature of the tank shell side wall 11.

The first hose 101, the second hose 102, and the third hose 103 are all metal hoses, and the ends of the metal hoses without flexible joints are welded to the corresponding connecting parts. A branch valve is provided at the junction of the main pipeline with the branch pipeline, and the branch valve can be provided on the first branch pipe 9 and the second branch pipe 10 to prevent dust from entering the main pipeline during installation. The heat exchange medium pipeline is a circulation pipeline, and a heat insulation layer is provided on the circulation pipeline, and a high temperature resistant protective cover is provided above the circulation pipeline.

Before installing the heat exchanger, the fixing bolts must be welded with a bolt welder at the corresponding installation positions of the tank shell side wall 11 and the vertical side wall 22 according to the bolt hole positions. The insulation layer is made of high temperature resistant and flame retardant materials such as silicate wool. The inner plate and the outer plate can be riveted or bolted or welded. The inner plate of the tank wall heat exchanger 5 and the cradle frame heat exchanger 6 is made of high thermal conductivity materials such as aluminum or copper, and the outer plate is made of non-magnetic materials such as stainless steel.

Since the side of the aluminum electrolytic cell needs to be arranged with a complex conductive busbar system around the cell, the space is small and the insulation requirements are also very high, so the installation order and safe operation of the heat exchanger are particularly important. Before installation, lay high-temperature resistant insulating rubber on the conductive busbars and cathode steel bars around the operating area to prevent short circuits between tools and heat exchangers during operation; use a polishing machine to clean the surface of the heat exchanger installation position on the side wall of the cell shell and the vertical side wall of the cradle to remove dust, protrusions, etc.; fix the main line bracket on the steel support frame outside the cradle with bolts; weld bolts on the heat exchanger installation position on the side wall of the cell shell and the cradle. Install the high-temperature and low-temperature main lines first, and then install the heat exchanger. The reason for installing the main line first is that the temperature of the cell wall is very high. Installing the main line first can shorten the dry burning time of the cell wall heat exchanger after installation; secondly, the heat exchanger will play a heat insulation role for the electrolytic cell when it is not working after installation. A long time will cause the melt temperature in the electrolytic cell to rise and the side furnace wall to melt, affecting the production of the electrolytic cell. In this embodiment, by active The setting of the joint allows the pipeline and the heat exchanger to be installed separately. Install the low-temperature and high-temperature main lines on the main line brackets around the electrolytic cell. When installing the main line, the branch valve should be closed first to prevent dust from entering the main line. After installing the main line, first install the deep tank wall heat exchanger, then install the cradle frame heat exchanger, and use metal hoses to connect the heat exchangers and the heat exchangers 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, set a heat insulation layer. Set a high-temperature resistant protective cover above the heat insulation layer of the high and low temperature main lines to prevent the electrolyte from dripping when replacing the anode.

The low-temperature heat exchange medium of 50℃～70℃ in the low-temperature main line flows into the cradle heat exchanger through the corresponding pipeline through the second inlet, and performs the first stage of heat exchange through the heat exchange structure inside the cradle heat exchanger and the vertical side wall of the cradle at 150℃～200℃. After the first stage of heat exchange, the heat exchange medium is heated to 70℃～90℃, and then enters the tank wall heat exchanger through the corresponding hose through the first inlet, and performs the second stage of heat exchange through the heat exchange structure inside the tank wall heat exchanger and the tank shell side wall at 300℃～400℃. After the heat exchange, the temperature rises to 150℃～170℃, and the high-temperature heat exchange medium after heat exchange enters the high-temperature main line through the corresponding pipeline and is transported out for heating or power generation.

By setting up a two-stage heat exchanger, the two-stage heat exchangers and the heat exchangers and the main pipeline are connected by hoses and flexible joints, which can ensure convenient and quick installation in the special space around the electrolytic cell. The secondary heat exchange structure on the cradle frame and the side wall of the tank shell of the aluminum electrolytic cell can increase the waste heat utilization rate by 10% to 40%, increase the heat exchange medium temperature by 10℃ to 30℃ compared with the existing technology, and greatly improve the quality of the heat source. Its structural design is reasonable, which can realize the high-value recovery of the waste heat of the aluminum electrolytic cell, and is more convenient for promotion and application.

Embodiment 2 of the electrolytic cell of the present invention:

This embodiment provides a different cradle heat exchanger arrangement from that of embodiment 1. The difference between this embodiment and embodiment 1 is that the cradle heat exchanger in embodiment 1 includes a heat-conducting contact surface for contacting with the vertical side wall of the cradle in the length direction of the electrolytic cell. In this embodiment, the cradle has an outer wall facing away from the side wall of the tank shell, and the cradle heat exchanger has a heat-conducting contact surface contacting with the outer wall of the cradle.

Embodiment 3 of the electrolytic cell of the present invention:

This embodiment provides a different arrangement of the heat-conducting contact surface from that of the first embodiment. The difference between this embodiment and the first embodiment is that a fastening connection structure for fixing with the vertical side wall is provided on the heat-conducting contact surface in the first embodiment. In this embodiment, no fastening connection structure is provided on the heat-conducting contact surface, a lug is provided on the cradle frame, and a fixing lug is provided on the outer plate of the cradle frame heat exchanger, and the fixing lug is fixedly connected with the lug by bolts.

Embodiment 4 of the electrolytic cell of the present invention:

This embodiment provides a different arrangement of the heat exchanger group from that of the first embodiment. The difference between this embodiment and the first embodiment is that the tank wall heat exchanger in the first embodiment is higher than the cradle frame heat exchanger in the vertical direction. In this embodiment, the upper end of the tank wall heat exchanger is flush with the upper end of the cradle frame heat exchanger.

Embodiment 5 of the electrolytic cell of the present invention:

This embodiment provides a different cradle heat exchanger arrangement from that of embodiment 1. The difference between this embodiment and embodiment 1 is that the cradle heat exchanger in embodiment 1 includes a heat exchange coil, which is spirally wound from the periphery to the center, and the heat exchange medium inlet end of the heat exchange coil is at the periphery and the heat exchange medium outlet end is led out from the center. In this embodiment, the heat exchange coil of the cradle heat exchanger is in a U-shaped winding form.

Embodiment 6 of the electrolytic cell of the present invention:

This embodiment provides a different cradle heat exchanger arrangement from that of Embodiment 1. The difference between this embodiment and Embodiment 1 is that the cradle heat exchanger in Embodiment 1 includes a heat exchange coil and a coil mounting plate, and the coil mounting plate is provided with a coil mounting groove for the heat exchange coil to be embedded. In this embodiment, the heat exchange coil of the cradle heat exchanger is clamped between the inner plate and the outer plate.

Embodiment 7 of the electrolytic cell of the present invention:

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

Embodiment 8 of the electrolytic cell of the present invention:

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 pipeline in Embodiment 1 includes a hose. In this embodiment, the branch pipelines are all hard pipes.

Embodiment 9 of the electrolytic cell of the present invention:

This embodiment provides a different arrangement of the tank wall heat exchanger from that of the first embodiment. The difference between this embodiment and the first embodiment is that the tank wall heat exchanger in the first embodiment 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.

Embodiment 10 of the electrolytic cell of the present invention:

This embodiment provides a different arrangement of heat exchange medium pipelines from that of embodiment 1. The difference between this embodiment and embodiment 1 is that the liquid inlet pipeline and the liquid outlet pipeline in embodiment 1 are arranged in parallel up and down. In this embodiment, the liquid inlet pipeline and the liquid outlet pipeline are arranged in parallel in the width direction of the electrolytic cell.

Embodiment of the electrolytic cell waste heat recovery device of the present invention:

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.

Finally, it should be noted that the above is only 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 above embodiments, those skilled in the art can still understand the above embodiments. The technical solutions described in the above embodiments can be modified without creative effort, or some of the technical features can be replaced by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

A waste heat recovery device for an electrolytic cell comprises 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 exchanging heat with the tank shell side wall of the electrolytic cell, and is characterized in that a cradle heat exchanger corresponding to the tank wall heat exchanger and constituting a heat exchanger group is also arranged 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 and the cradle heat exchanger is located upstream of the tank wall heat exchanger, and the cradle heat exchanger has a cradle heat conduction part for exchanging heat with the cradle side wall of the electrolytic cell. The electrolytic cell waste heat recovery device according to claim 1 is characterized in that 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 a heat-conducting portion of the cradle. The electrolytic cell waste heat recovery device according to claim 2 is characterized in that a fastening connection structure for fixing to the vertical side wall is provided on the heat conductive contact surface. The electrolytic cell waste heat recovery device according to claim 1, 2 or 3 is characterized in that the heat exchange medium inlet and the heat exchange medium outlet of the tank wall heat exchanger are higher than the cradle heat exchanger in the vertical direction. According to the electrolytic cell waste heat recovery device according to claim 1, 2 or 3, it is characterized in that the cradle heat exchanger includes a heat exchange coil, the heat exchange coil is spirally coiled 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 led out from the center. According to the electrolytic cell waste heat recovery device according to claim 1, 2 or 3, it is characterized in that 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. The electrolytic cell waste heat recovery device according to claim 1, 2 or 3 is characterized in that flexible joints are respectively 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. The electrolytic cell waste heat recovery device according to claim 7 is characterized in that 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. According to the electrolytic cell waste heat recovery device according to claim 1, 2 or 3, it is characterized in that the heat exchange medium pipeline includes a liquid inlet pipeline and a liquid outlet pipeline, the liquid inlet pipeline is used to be connected to the cradle heat exchanger, and the liquid outlet pipeline is used to be connected to the tank wall heat exchanger, and the liquid inlet pipeline and the liquid outlet pipeline are arranged in parallel up and down. An electrolytic cell comprises a cell shell, a cradle frame and an electrolytic cell waste heat recovery device, wherein 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.