Aluminum electrolysis cell waste heat recycling system and method

Abstract

The invention discloses an aluminum electrolysis cell waste heat recycling system and method 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 system and method for recovering waste heat from an aluminum electrolysis cell. Background Art

[0002] At present, aluminum electrolysis cells are the main equipment for primary aluminum production. The power utilization rate of aluminum electrolysis cells is low, and most of the power is directly lost in the form of heat. A large amount of test data shows that the waste heat recovery efficiency of aluminum electrolysis cells is generally low, very little heat will be recycled, and a large amount of waste heat will still be dissipated. Therefore, how to improve the waste heat recovery efficiency of aluminum electrolysis cells is a technical problem that needs to be solved urgently. Summary of the invention

[0003] 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.

[0004] In a first aspect of an embodiment of the present application, a waste heat recovery system for an aluminum electrolysis cell is provided, comprising: an aluminum electrolysis cell and a power generation system;

[0005] The aluminum electrolytic cell comprises a flue gas transport and collection pipe, the flue gas transport and collection pipe is used to transport the flue gas of the aluminum electrolytic cell, the flue gas transport and collection pipe is installed with a flue gas cooler, and the flue gas cooler is connected to the power generation system through a circulating medium transport pipe;

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

[0007] In some embodiments, the front end and the rear end of the flue gas cooler are both provided with adjustable electric valves, and the flue gas cooler is provided with a bypass flue;

[0008] The bypass flue is provided with an on-off electric valve and an adjustable air distribution valve. The on-off electric valve is used to control the switch of the flue gas, and the adjustable air distribution valve is used to control 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 do work. The work of the turbine is used to link the generator to generate electricity. The working fluid enters the condenser after being discharged from the turbine. 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 connected to 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 plates of the upper structure are 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 plates are sealedly connected to the side inner sealing plates, and the horizontal outer sealing plates are sealedly connected to the side outer sealing plates.

[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 insulation material; and / or,

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

[0015] A hanging hook is arranged on a side of the side inner sealing plate away from the inner cavity, and the hanging hook is used for hanging a heat preservation plate.

[0016] In some embodiments, the joint seam of the side inner sealing plate and the joint seam of the side outer sealing plate are staggered; and / or,

[0017] The spacing between the horizontal outer sealing plate and the horizontal inner sealing plate is in the range of 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 of 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 support tube is provided with a cigarette support tube electric valve.

[0023] A second aspect of the embodiment 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] Converts recovered waste heat into electrical energy.

[0026] The embodiment of the present application increases the available flue gas heat energy by setting a double-layer insulation sealing plate in the aluminum electrolytic cell and setting a flue gas recirculation induced draft pipeline between the gas collecting hood and the smoke pipe, thereby solving the technical problem of difficult efficient utilization due to low flue gas temperature and quality, and can realize the efficient recycling of a large amount of untapped flue gas waste heat. By setting a flue gas cooler in the flue gas transport and collection pipe, and setting a power generation system in the circulating medium pipeline of the flue gas cooler, the recovered heat energy is converted into high-grade electric energy and returned to the electrolytic aluminum production system, which is beneficial to energy saving 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, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of more restrictions, the elements limited by the statement "comprise one..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements. The term "more than two" includes two or more than two situations.

[0031] At present, aluminum electrolysis cells are the main equipment for primary aluminum production. The power utilization rate of aluminum electrolysis cells is low, and most of the power is directly lost in the form of heat. A large amount of test data shows that the waste heat recovery efficiency of aluminum electrolysis cells is generally low, very little heat will be recycled, and a large amount of waste heat will still be dissipated. Therefore, how to improve the waste heat recovery efficiency of aluminum electrolysis cells is a technical problem that needs to be solved urgently.

[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 an embodiment of the present application, a system for recovering waste heat from an aluminum electrolysis cell is provided. Figure 1 The following is a schematic structural diagram of a waste heat recovery system for an aluminum electrolysis cell provided in an embodiment of the present application. Figure 1 As shown, the aluminum electrolysis cell waste heat recovery and utilization system includes: an aluminum electrolysis cell 1 and a power generation system 3; the aluminum electrolysis cell 1 includes a flue gas transport header 12, and the flue gas transport header 12 is used to transmit the flue gas discharged from the aluminum electrolysis cell 1. The flue gas discharged from the aluminum electrolysis cell 1 is waste gas, and the flue gas usually carries a lot of heat. The flue gas transport header 12 is installed with a flue gas cooler 2, and the flue gas cooler 2 is connected to the power generation system 3 through a circulating medium transport pipe 13.

[0034] Exemplarily, 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, heat transfer 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 should be noted that the aluminum electrolytic cell is the main equipment for the production of primary aluminum. The power utilization rate of the aluminum electrolytic cell is usually less than 50%, and about half of the electricity is directly lost in the form of waste heat. A large amount of test data shows that the exhaust temperature of the aluminum electrolytic cell is generally 100-150℃, and the heat dissipation loss through the electrolytic cell flue gas accounts for 20-30% of the total heat dissipation, and the heat dissipation loss through the electrolytic cell sealing plate accounts for about 30-40% of the total heat dissipation. Taking the 300,000 tons of electrolytic aluminum production capacity as an example, the exhaust volume per hour is about 1.6 million cubic meters, and the volume of direct exhaust flue gas waste heat is huge. Due to the low temperature and grade of the flue gas, a very small part of the recovered flue gas waste heat is currently only used for hot water and heating in the plant area, and a large amount of waste heat needs to be developed and utilized. Based on this, how to improve the recovery and utilization of flue gas heat energy is a technical problem that needs to be solved for the efficient recovery and utilization of electrolytic cell waste heat.

[0037] In order to overcome the shortcomings of low recoverable amount and low utilization efficiency of flue gas waste heat in aluminum electrolysis, a double-layer sealing plate structure is set on the side, end and top of the electrolytic cell, and high-temperature resistant insulating materials are used for sealing at the electrolytic cell furnace door, triangular cover plate, side sealing plate, anode guide rod and shell cylinder gap to improve the insulation and airtightness of the electrolytic cell and reduce unorganized heat dissipation. By setting an induced draft pipeline between the electrolytic cell gas hood and the branch smoke pipe, it is convenient to dredge and clean the accumulated materials in the gas hood cavity, maintain the balance of the exhaust negative pressure, reduce the resistance and load of the exhaust system, and improve the flue gas temperature and the utilization efficiency of the rear-end waste heat. By setting an electric valve in the electrolytic cell branch flue, setting a flue gas cooler and a bypass pipe valve system in the flue gas transmission collection pipe, it is ensured that the exhaust temperature meets the requirements of the circulating medium heat exchange and the rear-end purification and dust removal process. By setting a power generation system in the circulating medium system, the recovered heat energy is converted into electrical energy, and the utilization value of the flue gas waste heat is improved.

[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 to a great extent, reducing the waste of flue gas heat dissipation.

[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. Both ends of the drainage air duct 1-7 are connected to the branch smoke pipe 14 and the gas collecting hood 1-5 respectively, and the drainage air duct 1-7 is provided with a drainage fan 1-6.

[0040] Exemplary, reference Figure 2A plurality of drainage ducts 1-7 are arranged in the gas collecting hood 1-5 of the aluminum electrolytic cell, and the drainage ducts 1-7 are connected to the branch smoke pipe 14 of the aluminum electrolytic cell, and a drainage fan 1-6 is arranged on the drainage duct 1-7. The induced draft system composed of the drainage fan 1-6 and the drainage duct 1-7 can circulate and drain the electrolytic flue gas discharged from the aluminum electrolytic cell 1 to the branch smoke pipe 14 into the cavity of the gas collecting hood 1-5, and then use the circulating wind to blow and clean the accumulated material 1-8 in the cavity of the gas collecting hood 1-5, so as to solve the problem that the gas collecting hood is easy to be blocked and affects the accumulation of the exhaust gas of the electrolytic cell, which is conducive to maintaining the balance of the exhaust negative pressure, reducing the exhaust resistance and the load of 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 smoke pipe 14 along the drainage air duct 1-7 and is heated by the inner cavity 1-9. The electrolytic flue gas refluxes 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 embodiment of the present application can greatly increase the temperature and heat of the flue gas by setting a double-layer heat-insulating sealed sealing plate in the aluminum electrolytic cell and setting a flue gas recirculation induced draft pipeline between the gas collecting hood and the smoke pipe, solving the technical problem of difficult efficient utilization due to low flue gas temperature and grade, and can realize the efficient recycling of a large amount of untapped flue gas waste heat. By setting a flue gas cooler in the flue gas transport and collection pipe, and setting a power generation system in the flue gas cooler circulating medium transport pipeline, the recovered heat energy can be converted into high-grade electric energy and returned to the electrolytic aluminum production system, which is beneficial to energy saving and emission reduction in aluminum electrolysis.

[0043] In some embodiments, the front and rear ends of the flue gas cooler are provided with regulating electric valves, and the flue gas cooler is provided with a bypass flue, which is used for daily 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 1, the flue gas transport collection pipe 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 to increase the temperature of the circulating medium. The front-end electric valve 6 of the flue gas cooler and the rear-end electric valve 9 of the flue gas cooler are respectively arranged before and after the flue gas cooler 2. When the flue gas cooler 2 needs to be repaired, the front-end electric valve 6 of the flue gas cooler and the rear-end electric valve 9 of the flue gas cooler are closed; when the flue gas cooler 2 is operating normally, the front-end electric valve 6 of the flue gas cooler and the rear-end electric valve 9 of the flue gas cooler are opened. The flue gas cooler 2 is also provided with a bypass flue 15, which is used for the normal discharge of the flue gas of the aluminum electrolytic cell when the flue gas cooler 2 is stopped; 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, and the opening and closing of the regulating air distribution valve 7 is used to add external low-temperature air to the high-temperature flue gas in the bypass, and regulate the flue gas temperature discharged into the purification system to meet 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 link the generator to generate electricity. The working fluid enters the condenser after being discharged from the turbine. 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 The power generation system 3 includes an evaporator 3-1, a turbine 3-2, a generator set 3-3, a condenser 3-4 and a working fluid pump 3-5. The flue gas cooler 2 exchanges hot water for the evaporator 3-1. The working fluid in the evaporator 3-1 increases in temperature and pressure to drive the turbine 3-2 to do work. The turbine 3-2 drives the generator set 3-3 to generate electricity. The working fluid is discharged from the turbine 3-2 and enters the condenser 3-4, where it changes from gas to liquid and circulates back to the evaporator 3-1 through the working fluid pump 3-5. The flue gas cooler 3 is provided with a circulating medium delivery pipe 13, into which cooling water can be passed, and the cooling water absorbs the heat of the flue gas and heats up to hot water, and the hot water is passed into the evaporator 3-1, and the evaporator 3-1 uses the heat of the hot water to increase the temperature and pressure of the working medium, and the temperature and pressure increase of the working medium can drive the turbine 3-2 to work, and the work of the turbine 3-2 can drive the generator to generate electricity, and the generator set 3-3 can include multiple generators, which can realize the conversion of thermal energy to electrical energy and recycle the heat energy of the aluminum electrolytic cell. Exemplarily, 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 structure includes 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 plate structure of the side outer sealing plate is filled with insulation material.

[0051] In some examples, a side of the side inner sealing plate and the horizontal inner sealing plate close to the inner cavity is 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 plate and the splicing seams of the side outer sealing plate are staggered. The side inner sealing plate and the side outer sealing plate can be formed by splicing multiple plates. The splicing seams of the side inner sealing plate and the side outer sealing plate are staggered to avoid heat dissipation directly from the splicing seams of the inner and outer sealing plates. 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 plate and the side inner sealing plate ranges from 5 to 20 cm.

[0056] Exemplary, reference Figure 1 and Figure 2 The side and end 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 5-20cm.

[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 helpful in suppressing the heat dissipation of the sealing plates.

[0059] Exemplary, reference Figure 2 The side inner sealing plate 1-2 and the side outer sealing plate 1-1 of the aluminum electrolytic cell are arranged in a double-layer hollow staggered arrangement, that is, there is a hollow gap between the side inner sealing plate 1-2 and the side outer sealing plate 1-1. The side inner sealing plate 1-2 and the side outer sealing plate 1-1 can be formed by splicing multiple plates, and the splicing gaps can be staggered. On the one hand, the good thermal insulation performance of air is utilized, and on the other hand, the flow and resistance of external air entering the electrolytic cell can be increased, which is beneficial to the electrolytic cell sealing plate to reduce heat dissipation and enhance sealing, and is beneficial to the original sealing plate to dissipate heat and gather to the flue gas, and improve the temperature and heat of the flue gas that can be used at the rear end. It can also reduce the overflow of unorganized flue gas in the tank, which is beneficial to the improvement of the on-site working environment.

[0060] In some embodiments, the furnace door, triangular cover plate, side sealing plate, anode guide rod and the gap of 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 reduction 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 branch pipe 14 of the aluminum electrolytic cell 1 is also provided with a smoke branch pipe regulating electric valve 4 for balanced control of the smoke flow of each electrolytic cell.

[0064] The embodiment of the present application provides a double-layer sealing plate structure on the side, end and top of the aluminum electrolytic cell, and adopts high temperature resistant insulating materials for sealing at the electrolytic cell door, triangular cover plate, side sealing plate, anode guide rod and shelling cylinder gap. By providing an induced draft duct between the gas collecting hood and the smoke pipe of the aluminum electrolytic cell, the heat preservation, airtightness and gas collection efficiency of the electrolytic cell are improved, and the unorganized heat dissipation is reduced. The flue gas temperature can be increased to 160-200°C, and the flue gas heat dissipation can be increased to 35%-45%, meeting the technical requirements of the back-end power generation process. The present invention converts the heat energy of the flue gas of the electrolytic cell into electrical energy, reduces the waste of flue gas waste heat, and improves the energy utilization efficiency of the electrolytic aluminum industry.

[0065] A second aspect of the embodiment 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] Converts recovered waste heat into electrical energy.

[0068] By setting up a double-layer sealing plate structure in the aluminum electrolytic cell, using high-temperature resistant insulating materials to seal each gap in the electrolytic cell, and setting up an induced draft pipeline between the electrolytic cell gas hood and the branch flue pipe, the overall flue gas temperature and the efficiency of the rear-end waste heat utilization are improved. By setting up an electric valve in the branch flue of the electrolytic cell, a flue gas cooler in the aggregate flue, and a power generation system in the circulating medium system, the recovered heat energy is converted into electrical energy, thereby improving the utilization value of the flue gas waste heat.

[0069] The described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are 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 concept. 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 can make various changes and modifications to this specification without departing from the spirit and scope of this specification. Thus, if these modifications and variations of this specification fall within the scope of the claims of this specification and their equivalents, this specification is also intended to include these modifications and variations.

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 electrolytic cell comprises a flue gas transport and collection pipe, the flue gas transport and collection pipe is used to transport the flue gas of the aluminum electrolytic cell, the flue gas transport and collection pipe is installed with a flue gas cooler, and the flue gas cooler is connected to the power generation system through a circulating medium transport pipe; The aluminum electrolytic cell includes a gas collecting hood, a smoke branch pipe and a drainage air duct. The smoke branch pipe is connected between the smoke transport main pipe and the gas collecting hood. The two ends of the drainage air duct are respectively connected to the smoke branch 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 is 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 an adjustable air distribution valve. The on-off electric valve is used to control the switch of the flue gas, and the adjustable air distribution valve is used to control the flue gas temperature.

3. The aluminum electrolysis cell waste heat recovery system according to claim 1 is 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 do work. The work of the turbine is used to link the generator to generate electricity. The working fluid enters the condenser after being discharged from the turbine. 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 and utilization system according to claim 1 is characterized in that: The aluminum electrolysis cell comprises an upper structure, the upper structure comprises 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 plates of the upper structure are 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 plates are sealedly connected to the side inner sealing plates, and the horizontal outer sealing plates are sealedly connected to the side outer sealing plates.

5. The aluminum electrolysis cell waste heat recovery system according to claim 4 is 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 is 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 horizontal inner sealing plate close to the inner cavity are coated with thermal insulation coating; and / or, A hanging hook is arranged on a side of the side inner sealing plate away from the inner cavity, and the hanging hook is used for hanging a heat preservation plate.

7. The aluminum electrolysis cell waste heat recovery and utilization system according to claim 4 is 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 furnace door, triangular cover plate, side sealing plate, anode guide rod and shelling cylinder of the electrolytic cell are 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.

9. The aluminum electrolysis cell waste heat recovery 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 supporting tube is provided with a cigarette supporting tube electric valve.

10. A method for recovering waste heat from an aluminum electrolysis cell, characterized in that: include: Recover the waste heat of the aluminum electrolysis cell by using the aluminum electrolysis cell waste heat recovery and utilization system as described in any one of claims 1 to 9; Converts recovered waste heat into electrical energy.

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