Waste heat recycling system for aluminum electrolysis cell

Abstract

The utility model discloses an aluminum electrolysis cell waste heat recycling system which can improve the waste heat recycling efficiency of an aluminum electrolysis cell and reduce energy waste. The aluminum electrolysis cell waste heat recycling system comprises an aluminum electrolysis cell and a power generation system. The aluminum electrolysis cell comprises a flue gas conveying and gathering pipe, the flue gas conveying and gathering pipe is used for conveying flue gas of the aluminum electrolysis cell, the flue gas conveying and gathering pipe is provided with a flue gas cooler, and the flue gas cooler is connected with the power generation system through a circulating medium conveying pipe; the aluminum electrolysis cell comprises a gas collecting hood, a branch smoke pipe and a drainage air pipe, the branch smoke pipe is communicated between the smoke conveying gathering pipe and the gas collecting hood, the two ends of the drainage air pipe are communicated with the branch smoke pipe and the gas collecting hood respectively, and the drainage air pipe is provided with a drainage fan.

Description

Technical Field

[0001] The present application relates to the technical field of aluminum electrolysis, and in particular to a waste heat recovery and utilization system for aluminum electrolysis cells. Background Art

[0002] Currently, aluminum electrolysis cells, the primary equipment in primary aluminum production, have low electrical energy utilization rates, with most of the energy being dissipated directly as heat. Extensive test data indicates that the waste heat recovery efficiency of aluminum electrolysis cells is generally low, with very little heat being recovered and a significant amount being dissipated. Therefore, improving the waste heat recovery efficiency of aluminum electrolysis cells is a pressing technical challenge. Utility Model Content

[0003] The embodiment of the present application provides a waste heat recovery and utilization system for an aluminum electrolysis cell, which can improve the waste heat recovery efficiency of the aluminum electrolysis cell and reduce energy waste.

[0004] A first aspect of an embodiment of the present application provides an aluminum electrolysis cell waste heat recovery and utilization system, comprising: an aluminum electrolysis cell and a power generation system;

[0005] The aluminum electrolysis cell includes a flue gas transport manifold, which is used to transport the flue gas from the aluminum electrolysis cell. The flue gas transport manifold is installed with a flue gas cooler, which is connected to the power generation system through a circulating medium transport pipe.

[0006] The aluminum electrolytic cell includes a gas collecting hood, a branch smoke pipe and a drainage air duct. The branch smoke pipe is connected between the smoke conveying main pipe and the gas collecting hood. The two ends of the drainage air duct are respectively connected to the branch smoke pipe and the gas collecting hood. The drainage air duct is provided with a drainage fan.

[0007] In some embodiments, the flue gas cooler is provided with an adjustable electric valve at the front end and the rear end, and the flue gas cooler is provided with a bypass flue;

[0008] The bypass flue is provided with an on-off electric valve and a regulating air distribution valve. The on-off electric valve is used to control the on-off of the flue gas, and the regulating air distribution valve is used to regulate the flue gas temperature.

[0009] In some embodiments, the power generation system includes an evaporator, a turbine, a generator, a working fluid pump and a condenser. The flue gas cooler is used to pass the output heat medium into the evaporator. The working fluid in the evaporator is heated and pressurized to drive the turbine to work. The work of the turbine is used to link the generator to generate electricity. The working fluid is discharged from the turbine and enters the condenser. The working fluid is converted from gas to liquid and then circulated to the evaporator through the working fluid pump.

[0010] In some embodiments, the aluminum electrolysis cell includes an upper structure, the upper structure includes an inner cavity, and the inner cavity is in communication with the gas collecting hood;

[0011] The sides and ends of the upper structure are provided with inner and outer double-layer sealing plate structures, the inner and outer double-layer sealing plate structures of the sides include side inner sealing plates and side outer sealing plates, the upper horizontal sealing plate of the upper structure is provided with upper and lower double-layer sealing plate structures, the upper and lower double-layer sealing plate structures include horizontal inner sealing plates and horizontal outer sealing plates, the horizontal inner sealing plate is sealedly connected to the side inner sealing plate, and the horizontal outer sealing plate is sealedly connected to the side outer sealing plate.

[0012] In some embodiments, the side inner sealing plate is a single-layer plate structure, and / or the side outer sealing plate is a double-layer plate structure.

[0013] In some embodiments, the double-layer plate structure of the side outer sealing plate is filled with thermal insulation material; and / or,

[0014] The side inner sealing plate and the side of the horizontal inner sealing plate close to the inner cavity are coated with thermal insulation coating; and / or,

[0015] A hanging hook is provided on the side of the side inner layer sealing plate away from the inner cavity, and the hanging hook is used for hanging the insulation board.

[0016] In some embodiments, the splicing seam of the side inner sealing panel and the splicing seam of the side outer sealing panel are staggered.

[0017] In some embodiments, the distance between the horizontal outer sealing plate and the horizontal inner sealing plate ranges from 5 to 10 cm; and / or,

[0018] The distance between the side outer sealing plate and the side inner sealing plate ranges from 5 to 20 cm.

[0019] In some embodiments, the furnace door, triangular cover plate, side sealing plate, anode guide rod and the gap between the shelling cylinder of the electrolytic cell are all sealed with high temperature resistant insulating materials; and / or,

[0020] The connecting pipes between the aluminum electrolytic cell and the flue gas cooler are insulated with thermal insulation materials.

[0021] In some embodiments, the collecting pipe is provided with a flue gas temperature measuring thermocouple and a flue gas flow meter, and the tail end of the collecting pipe is provided with a purification and dust removal system;

[0022] The cigarette branch pipe is provided with a cigarette branch pipe electric valve.

[0023] A second aspect of the embodiments of the present application provides a method for recovering waste heat from an aluminum electrolysis cell, comprising:

[0024] Recovering the waste heat of the aluminum electrolysis cell using the aluminum electrolysis cell waste heat recovery and utilization system as described in the first aspect;

[0025] Convert recovered waste heat into electrical energy.

[0026] The embodiments of the present application increase the available flue gas heat energy by installing a double-layer insulation sealing plate in the aluminum electrolytic cell and a flue gas recirculation duct between the gas hood and the flue gas branch pipe. This solves the technical problem of the low temperature and quality of flue gas, which is difficult to efficiently utilize, and can effectively recover and utilize a large amount of untapped flue gas waste heat. By installing a flue gas cooler in the flue gas transport and collection pipe and a power generation system in the flue gas cooler's circulating medium pipeline, the recovered heat energy is converted into high-grade electricity and returned to the electrolytic aluminum production system, which is beneficial to energy conservation and emission reduction in aluminum electrolysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic structural diagram of a waste heat recovery system for an aluminum electrolysis cell provided in an embodiment of the present application;

[0028] Figure 2 A partial schematic diagram of the upper structure of an aluminum electrolysis cell provided in an embodiment of the present application. DETAILED DESCRIPTION

[0029] In order to better understand the technical solutions provided by the embodiments of this specification, the technical solutions of the embodiments of this specification are described in detail below through the accompanying drawings and specific embodiments. It should be understood that the embodiments of this specification and the specific features in the embodiments are detailed descriptions of the technical solutions of the embodiments of this specification, rather than limitations on the technical solutions of this specification. In the absence of conflict, the embodiments of this specification and the technical features in the embodiments can be combined with each other.

[0030] In this article, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also include elements inherent to such process, method, article or equipment. In the absence of further restrictions, the elements defined by the statement "comprising a ..." do not exclude the presence of other identical elements in the process, method, article or equipment comprising the elements. The term "two or more" includes two or more than two cases.

[0031] Currently, aluminum electrolysis cells, the primary equipment in primary aluminum production, have low electrical energy utilization rates, with most of the energy being dissipated directly as heat. Extensive test data indicates that the waste heat recovery efficiency of aluminum electrolysis cells is generally low, with very little heat being recovered and a significant amount being dissipated. Therefore, improving the waste heat recovery efficiency of aluminum electrolysis cells is a pressing technical challenge.

[0032] In view of this, the embodiments of the present application provide a system and method for recovering waste heat from an aluminum electrolysis cell, which can improve the waste heat recovery efficiency of the aluminum electrolysis cell and reduce energy waste.

[0033] In a first aspect of the embodiments of the present application, a system for recovering waste heat from an aluminum electrolysis cell is provided. Figure 1 This is a schematic structural diagram of a waste heat recovery system for an aluminum electrolysis cell provided in an embodiment of the present application. For example, Figure 1 As shown, the aluminum electrolysis cell waste heat recovery system includes an aluminum electrolysis cell 1 and a power generation system 3. The aluminum electrolysis cell 1 includes a flue gas manifold 12 for transporting flue gas discharged from the aluminum electrolysis cell 1. The flue gas discharged from the aluminum electrolysis cell 1 is waste gas and typically carries a high amount of heat. A flue gas cooler 2 is installed on the flue gas manifold 12, which is connected to the power generation system 3 via a circulating medium delivery pipe 13.

[0034] For example, the power generation system 3 may include a steam combined cycle power generation system, an organic Rankine cycle power generation system, a water steam Rankine cycle power generation system, or a Kalina cycle power generation system, etc. The medium transported by the circulating medium transport pipe may be water, thermal oil, air, or other fluid media.

[0035] Exemplary, reference Figure 1 The flue gas cooler 2 can cool the flue gas discharged from the aluminum electrolytic cell 1. The cooling process is a heat exchange process. The heat obtained by the heat exchange in the flue gas cooling is collected, and the power generation system 3 can be used to convert the heat into electrical energy to realize the reuse of the waste heat recovery of the aluminum electrolytic cell.

[0036] It's important to note that aluminum electrolytic cells, the core equipment in primary aluminum production, typically have an electricity utilization rate of less than 50%, with approximately half of the electricity being directly dissipated as waste heat. Extensive test data indicates that the exhaust temperature of aluminum electrolytic cells is typically between 100-150°C, with heat loss through the cell flue gases accounting for 20-30% of the total heat dissipation, and heat loss through the cell sealing plates accounting for approximately 30-40%. For a 300,000-ton electrolytic aluminum production capacity, the exhaust volume is approximately 1.6 million cubic meters per hour, resulting in a significant amount of waste heat from the directly discharged flue gases. Due to the low temperature and quality of the flue gases, the minimal amount of waste heat currently recovered is used solely for hot water and heating within the plant, leaving a significant amount of waste heat untapped for development and utilization. Therefore, improving flue gas heat recovery is a pressing technical challenge for the efficient recovery of waste heat from electrolytic cells.

[0037] To overcome the limitations of low recoverable waste heat and low utilization efficiency of flue gas from aluminum electrolysis, a double-layer sealing plate structure is installed on the sides, ends, and top of the electrolytic cell. High-temperature-resistant insulating materials are used to seal the cell door, triangular cover, side sealing plates, anode guide rods, and the gaps between the shelling cylinders. This improves the cell's thermal insulation and airtightness, and reduces unorganized heat dissipation. An induced draft duct is installed between the electrolytic cell's gas hood and the branch flue pipe to facilitate the removal of accumulated material within the hood cavity, maintain balanced exhaust negative pressure, reduce exhaust system resistance and load, and improve flue gas temperature and back-end waste heat utilization efficiency. Electric valves are installed in the electrolytic cell branch flue ducts, and a flue gas cooler and bypass valve system are installed in the flue gas transmission manifold to ensure that the exhaust temperature meets the requirements of the circulating medium heat exchange and back-end purification and dust removal processes. A power generation system is installed in the circulating medium system to convert recovered heat energy into electricity, thereby increasing the utilization value of flue gas waste heat.

[0038] By setting up a flue gas cooler to collect the heat of the flue gas through heat exchange, and then converting the collected heat into electrical energy through the power generation system 3, the flue gas heat of the aluminum electrolytic cell can be recycled and utilized to a great extent, reducing the dissipation and waste of flue gas heat.

[0039] Figure 2 A partial schematic diagram of the upper structure of an aluminum electrolysis cell provided in an embodiment of the present application. Figure 1 and Figure 2 The aluminum electrolytic cell 1 includes a gas collecting hood 1-5, a branch smoke pipe 14 and a drainage air duct 1-7. One end of the branch smoke pipe 14 is connected to the smoke conveying and collecting pipe 12, and the other end of the branch smoke pipe 14 is connected to the gas collecting hood 1-5. The two ends of the drainage air duct 1-7 are respectively connected to the branch smoke pipe 14 and the gas collecting hood 1-5. The drainage air duct 1-7 is provided with a drainage fan 1-6.

[0040] Exemplary, reference Figure 2The aluminum electrolytic cell's gas collection hood 1-5 is equipped with several drainage ducts 1-7, which are connected to the cell's flue pipes 14. These ducts are equipped with drainage fans 1-6. The induced draft system, comprised of the drainage fans 1-6 and ducts 1-7, circulates and drains the electrolytic flue gas discharged from the aluminum electrolytic cell 1 into the flue pipes 14 into the cavity of the gas collection hood 1-5. The circulating air then clears accumulated material 1-8 within the cavity of the gas collection hood 1-5, resolving the issue of the gas collection hood being easily clogged and impacting the accumulation of exhaust gas from the electrolytic cell. This helps maintain a balanced exhaust negative pressure, reduces exhaust resistance, and reduces the load on the purification system.

[0041] refer to Figure 2 The aluminum electrolytic cell 1 includes an upper structure 1-S, and the upper structure 1-S includes an inner cavity 1-9. The inner cavity 1-9 has a relatively high temperature. The flue gas returns to the gas collecting hood 1-5 from the branch pipe 14 along the drainage air duct 1-7 and will be heated by the inner cavity 1-9. The electrolytic flue gas flows back into the electrolytic cell, and the secondary heating temperature of the flue gas is further increased, which is beneficial to improving the efficiency of waste heat recovery and utilization at the rear end.

[0042] The embodiments of the present application significantly increase the flue gas temperature and heat by installing a double-layer thermal insulation and airtight sealing plate in the aluminum electrolytic cell and a flue gas recirculation duct between the gas collecting hood and the flue gas branch pipe. This solves the technical problem of the difficulty in efficiently utilizing the flue gas due to its low temperature and quality, and enables the efficient recovery and utilization of a large amount of untapped flue gas waste heat. By installing a flue gas cooler in the flue gas transport and collection pipe and a power generation system in the flue gas cooler circulating medium transport pipeline, the recovered heat energy is converted into high-grade electricity and returned to the electrolytic aluminum production system, which is beneficial to energy conservation and emission reduction in aluminum electrolysis.

[0043] In some embodiments, the front and rear ends of the flue gas cooler are both provided with regulating electric valves, and the flue gas cooler is provided with a bypass flue, which is used for routine maintenance of the flue gas cooler; the bypass flue is provided with a switch-type electric valve and a regulating air distribution valve, the switch-type electric valve is used to control the switch of the flue gas, and the regulating air distribution valve is used to regulate the flue gas temperature.

[0044] Exemplary, reference Figure 1The flue gas transport manifold 12 of the aluminum electrolytic cell 1 is equipped with a flue gas cooler 2, which transfers the heat in the flue gas to the low-temperature circulating medium, thereby increasing the temperature of the circulating medium. The flue gas cooler 2 is provided with a front-end electric valve 6 and a rear-end electric valve 9, respectively. When the flue gas cooler 2 needs to be repaired, the front-end electric valve 6 and the rear-end electric valve 9 are closed; when the flue gas cooler 2 is operating normally, the front-end electric valve 6 and the rear-end electric valve 9 are opened. The flue gas cooler 2 is also provided with a bypass flue 15, which is used to ensure the normal discharge of the flue gas from the aluminum electrolytic cell when the flue gas cooler 2 is shut down; the bypass flue 15 is provided with a switch-type electric valve 8 and a regulating air distribution valve 7. The switch-type electric valve 8 is used to control the opening and closing of the flue gas passage, and the regulating air distribution valve 7 is opened and closed to supply external low-temperature air to the high-temperature flue gas in the bypass, thereby regulating the temperature of the flue gas discharged into the purification system and meeting the requirements of the rear-end flue gas purification and dust removal process.

[0045] In some embodiments, the power generation system includes an evaporator, a turbine, a generator, a working fluid pump and a condenser. The flue gas cooler is used to pass the output heat medium into the evaporator. The working fluid in the evaporator is heated and pressurized to drive the turbine to work. The work of the turbine is used to drive the generator to generate electricity. After being discharged from the turbine, the working fluid enters the condenser, and the working fluid is converted from gas to liquid and then circulated to the evaporator through the working fluid pump.

[0046] Exemplary, reference Figure 1 Power generation system 3 includes evaporator 3-1, turbine 3-2, generator set 3-3, condenser 3-4, and working fluid pump 3-5. Hot water is exchanged from flue gas cooler 2 and fed into evaporator 3-1. The working fluid in evaporator 3-1 heats up, driving turbine 3-2 to produce work. Turbine 3-2 then drives generator set 3-3 to generate electricity. After exiting turbine 3-2, the working fluid enters condenser 3-4, where it transforms from a gaseous state to a liquid state. It then circulates back to evaporator 3-1 via working fluid pump 3-5. The flue gas cooler 3 is provided with a circulating medium delivery pipe 13, into which cooling water can flow. The cooling water absorbs the heat of the flue gas and heats it to hot water. The hot water is then passed into the evaporator 3-1. The evaporator 3-1 uses the heat from the hot water to increase the temperature and pressure of the working medium. The increased temperature and pressure of the working medium drives the turbine 3-2 to produce work. The work produced by the turbine 3-2 drives the generator to generate electricity. The generator set 3-3 can include multiple generators, which can achieve the conversion of thermal energy into electrical energy and recycle the heat energy of the aluminum electrolytic cell. For example, the working medium can be an organic working medium or other working medium, which is not specifically limited in this application.

[0047] In some embodiments, the aluminum electrolysis cell includes an upper structure, the upper structure includes an inner cavity, and the inner cavity is connected to the gas collecting hood; the sides and ends of the upper structure are provided with inner and outer double-layer sealing plate structures, the inner and outer double-layer sealing plate structures of the side include a side inner sealing plate and a side outer sealing plate, the upper horizontal sealing plate of the upper structure is provided with an upper and lower double-layer sealing plate structure, the upper and lower double-layer sealing plate structures include a horizontal inner sealing plate and a horizontal outer sealing plate, the horizontal inner sealing plate is sealedly connected to the side inner sealing plate, and the horizontal outer sealing plate is sealedly connected to the side outer sealing plate.

[0048] In some examples, the side inner sealing panel is a single-layer panel structure.

[0049] In some examples, the side outer sealing plate is a double-layer plate structure.

[0050] In some examples, the double-layer panel structure of the side outer sealing panel is filled with insulation material.

[0051] In some examples, the side inner sealing plate and the side of the horizontal inner sealing plate close to the inner cavity are coated with thermal insulation coating.

[0052] In some examples, a hook is provided on the side of the side inner sealing plate away from the inner cavity, and the hook is used to mount the insulation plate to facilitate the adjustment of the insulation of the electrolytic cell sealing plate and the heat dissipation of the upper part according to the changes in ambient temperature.

[0053] In some examples, the splicing seams of the side inner sealing panel and the splicing seams of the side outer sealing panel are staggered. The side inner sealing panel and the side outer sealing panel can be formed by splicing multiple panels. The staggered splicing seams of the side inner sealing panel and the side outer sealing panel can prevent heat from dissipating directly from the splicing seams of the inner and outer sealing panels. The staggered splicing seams can delay heat dissipation and play a role in thermal insulation.

[0054] In some examples, the spacing between the horizontal outer sealing plate and the horizontal inner sealing plate ranges from 5 to 10 cm.

[0055] In some examples, the spacing between the side outer sealing panel and the side inner sealing panel ranges from 5 to 20 cm.

[0056] Exemplary, reference Figure 1 and Figure 2 The sides and ends of the aluminum electrolytic cell 1 adopt an inner and outer double-layer sealing plate structure. The side outer sealing plate 1-1 can be a double-layer plate structure. The double-layer structure of the side outer sealing plate 1-1 can be filled with insulation material. The side inner sealing plate 1-2 can be a single-layer plate structure. The distance between the inner and outer layers of the side sealing plate is 5-20 cm.

[0057] Exemplary, reference Figure 2The upper horizontal sealing plate of the aluminum electrolytic cell can adopt an upper and lower double-layer sealing plate structure, the horizontal inner sealing plate 1-3 is sealed and connected with the side inner sealing plate 1-2, the horizontal outer sealing plate 1-4 is sealed and connected with the side outer sealing plate 1-1, and the distance between the inner and outer layers of the horizontal sealing plate is 5-10cm.

[0058] Exemplary, reference Figure 2 The inner sides of the side inner sealing plates 1-2 and the horizontal inner sealing plates 1-3 of the aluminum electrolytic cell are also coated with thermal insulation coatings, which are beneficial to suppressing heat dissipation of the sealing plates.

[0059] Exemplary, reference Figure 2 The inner side sealing plate 1-2 and the outer side sealing plate 1-1 of the aluminum electrolytic cell are arranged in a double-layer hollow staggered pattern, that is, there is a hollow gap between the inner side sealing plate 1-2 and the outer side sealing plate 1-1. The inner side sealing plate 1-2 and the outer side sealing plate 1-1 can be formed by splicing multiple plates, and the splicing gaps can be staggered. On the one hand, it takes advantage of the good thermal insulation properties of air, and on the other hand, it can increase the flow and resistance of external air entering the electrolytic cell, which is beneficial to reduce heat dissipation and enhance the sealing of the electrolytic cell sealing plate, and is beneficial for the original sealing plate to dissipate heat and gather it into the flue gas, thereby increasing the temperature and heat of the flue gas available at the back end. It can also reduce the overflow of unorganized flue gas in the cell, which is beneficial to improving the on-site working environment.

[0060] In some embodiments, the furnace door, triangular cover plate, side sealing plate, anode guide rod and the gap between the shelling cylinder of the electrolytic cell are all sealed with high temperature resistant insulating materials.

[0061] In some examples, the connecting pipes between the aluminum electrolysis cell and the flue gas cooler are insulated with thermal insulation materials.

[0062] In some examples, the collecting pipe is provided with a flue gas temperature measuring thermocouple and a flue gas flow meter, and the tail end of the collecting pipe is provided with a purification and dust removal system; the branch pipes are provided with branch pipe electric valves.

[0063] Exemplary, reference Figure 1 The smoke pipe 14 of the aluminum electrolytic cell 1 is also provided with a smoke pipe regulating electric valve 4 for balanced control of the smoke flow of each electrolytic cell.

[0064] The present invention provides a double-layer sealing plate structure on the sides, ends, and top of the aluminum electrolytic cell. High-temperature-resistant insulating materials are used to seal the cell door, triangular cover, side sealing plate, anode guide rod, and shelling cylinder gap. Furthermore, an induced draft duct is provided between the gas collection hood and the flue pipe of the aluminum electrolytic cell. This improves the cell's thermal insulation, airtightness, and gas collection efficiency, reduces unorganized heat dissipation, and increases the flue gas temperature to 160-200°C and the flue gas heat dissipation to 35%-45%, meeting the technical requirements of the back-end power generation process. The present invention converts the thermal energy of the electrolytic cell flue gas into electrical energy, reducing waste of flue gas waste heat and improving energy utilization efficiency in the electrolytic aluminum industry.

[0065] A second aspect of the embodiments of the present application provides a method for recovering waste heat from an aluminum electrolysis cell, comprising:

[0066] Recovering waste heat from the aluminum electrolysis cell using the aluminum electrolysis cell waste heat recovery and utilization system as described in the first aspect;

[0067] Convert recovered waste heat into electrical energy.

[0068] By installing a double-layer sealing plate structure in the aluminum electrolytic cell, sealing all gaps in the electrolytic cell with high-temperature resistant insulating materials, and installing an induced draft duct between the electrolytic cell gas hood and the branch flue, the overall flue gas temperature and the efficiency of back-end waste heat utilization are improved. By installing electric valves in the electrolytic cell branch flue, a flue gas cooler in the main flue, and a power generation system in the circulating medium system, the recovered heat is converted into electricity, thereby increasing the utilization value of flue gas waste heat.

[0069] The embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work shall fall within the scope of protection of the present invention.

[0070] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

[0071] Although the preferred embodiments of this specification have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of this specification.

[0072] Obviously, those skilled in the art may make various changes and modifications to this specification without departing from the spirit and scope of this specification. Thus, if such changes and modifications fall within the scope of the claims of this specification and their equivalents, this specification is intended to include such changes and modifications.

Claims

1. A waste heat recovery system for an aluminum electrolysis cell, characterized in that: include: Aluminum electrolysis cells and power generation systems; The aluminum electrolysis cell includes a flue gas transport manifold, which is used to transport the flue gas from the aluminum electrolysis cell. The flue gas transport manifold is installed with a flue gas cooler, which is connected to the power generation system through a circulating medium transport pipe. The aluminum electrolytic cell includes a gas collecting hood, a branch smoke pipe and a drainage air duct. The branch smoke pipe is connected between the smoke conveying main pipe and the gas collecting hood. The two ends of the drainage air duct are respectively connected to the branch smoke pipe and the gas collecting hood. The drainage air duct is provided with a drainage fan.

2. The aluminum electrolysis cell waste heat recovery and utilization system according to claim 1, characterized in that: The front end and the rear end of the flue gas cooler are both provided with regulating electric valves, and the flue gas cooler is provided with a bypass flue; The bypass flue is provided with an on-off electric valve and a regulating air distribution valve. The on-off electric valve is used to control the on-off of the flue gas, and the regulating air distribution valve is used to regulate the flue gas temperature.

3. The aluminum electrolysis cell waste heat recovery and utilization system according to claim 1, characterized in that: The power generation system includes an evaporator, a turbine, a generator, a working fluid pump and a condenser. The flue gas cooler is used to pass the output heat medium into the evaporator. The working fluid in the evaporator is heated and pressurized to drive the turbine to work. The work of the turbine is used to link the generator to generate electricity. The working fluid is discharged from the turbine and enters the condenser. The working fluid is converted from gas to liquid and then circulated to the evaporator through the working fluid pump.

4. The aluminum electrolysis cell waste heat recovery system according to claim 1, characterized in that: The aluminum electrolysis cell includes an upper structure, the upper structure includes an inner cavity, and the inner cavity is communicated with the gas collecting hood; The sides and ends of the upper structure are provided with inner and outer double-layer sealing plate structures, the inner and outer double-layer sealing plate structures of the sides include side inner sealing plates and side outer sealing plates, the upper horizontal sealing plate of the upper structure is provided with upper and lower double-layer sealing plate structures, the upper and lower double-layer sealing plate structures include horizontal inner sealing plates and horizontal outer sealing plates, the horizontal inner sealing plate is sealedly connected to the side inner sealing plate, and the horizontal outer sealing plate is sealedly connected to the side outer sealing plate.

5. The aluminum electrolysis cell waste heat recovery and utilization system according to claim 4, characterized in that: The side inner sealing plate is a single-layer plate structure, and / or the side outer sealing plate is a double-layer plate structure.

6. The aluminum electrolysis cell waste heat recovery and utilization system according to claim 4, characterized in that: The double-layer plate structure of the side outer sealing plate is filled with thermal insulation material; and / or, The side inner sealing plate and the side of the horizontal inner sealing plate close to the inner cavity are coated with thermal insulation coating; and / or, A hanging hook is provided on the side of the side inner layer sealing plate away from the inner cavity, and the hanging hook is used for hanging the insulation board.

7. The aluminum electrolysis cell waste heat recovery and utilization system according to claim 4, characterized in that: The splicing seam of the side inner sealing plate and the splicing seam of the side outer sealing plate are staggered.

8. The aluminum electrolysis cell waste heat recovery system according to claim 4, characterized in that: The distance between the horizontal outer sealing plate and the horizontal inner sealing plate is in the range of 5 to 10 cm; and / or, The distance between the side outer sealing plate and the side inner sealing plate ranges from 5 to 20 cm.

9. The aluminum electrolysis cell waste heat recovery and utilization system according to claim 4, characterized in that: The furnace door, triangular cover plate, side sealing plate, anode guide rod and shelling cylinder of the electrolytic cell are all sealed with high temperature resistant insulating materials; and / or, The connecting pipes between the aluminum electrolytic cell and the flue gas cooler are insulated with thermal insulation materials.

10. The aluminum electrolysis cell waste heat recovery and utilization system according to claim 1, characterized in that: The collecting pipe is provided with a flue gas temperature measuring thermocouple and a flue gas flow meter, and the tail end of the collecting pipe is provided with a purification and dust removal system; The cigarette branch pipe is provided with a cigarette branch pipe electric valve.

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