CN116676640A - Heat exchange system, aluminum electrolysis cell system and heat balance control method - Google Patents
Heat exchange system, aluminum electrolysis cell system and heat balance control method Download PDFInfo
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- CN116676640A CN116676640A CN202310640608.XA CN202310640608A CN116676640A CN 116676640 A CN116676640 A CN 116676640A CN 202310640608 A CN202310640608 A CN 202310640608A CN 116676640 A CN116676640 A CN 116676640A
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- 229910052782 aluminium Inorganic materials 0.000 title claims abstract description 151
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 title claims abstract description 137
- 238000005868 electrolysis reaction Methods 0.000 title claims abstract description 125
- 238000000034 method Methods 0.000 title claims abstract description 18
- 210000004027 cell Anatomy 0.000 claims description 171
- 229910052751 metal Inorganic materials 0.000 claims description 66
- 239000002184 metal Substances 0.000 claims description 66
- 230000017525 heat dissipation Effects 0.000 claims description 45
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 19
- 239000004411 aluminium Substances 0.000 claims description 19
- 229910052799 carbon Inorganic materials 0.000 claims description 19
- 239000007789 gas Substances 0.000 claims description 17
- 239000007788 liquid Substances 0.000 claims description 15
- 239000003792 electrolyte Substances 0.000 claims description 11
- 238000009413 insulation Methods 0.000 claims description 11
- 239000004964 aerogel Substances 0.000 claims description 8
- 239000013078 crystal Substances 0.000 claims description 6
- 230000007246 mechanism Effects 0.000 claims description 6
- 230000005855 radiation Effects 0.000 claims description 6
- 238000012546 transfer Methods 0.000 claims description 5
- 239000003365 glass fiber Substances 0.000 claims description 2
- 239000011490 mineral wool Substances 0.000 claims description 2
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical compound [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 abstract description 14
- 230000033228 biological regulation Effects 0.000 abstract description 3
- 230000001737 promoting effect Effects 0.000 abstract 1
- 230000001105 regulatory effect Effects 0.000 description 10
- 238000004321 preservation Methods 0.000 description 8
- 238000004364 calculation method Methods 0.000 description 7
- 230000001276 controlling effect Effects 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 229910000831 Steel Inorganic materials 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 238000004088 simulation Methods 0.000 description 5
- 239000010959 steel Substances 0.000 description 5
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 4
- 229910052802 copper Inorganic materials 0.000 description 4
- 239000010949 copper Substances 0.000 description 4
- 238000010248 power generation Methods 0.000 description 4
- 229910000881 Cu alloy Inorganic materials 0.000 description 3
- 210000002421 cell wall Anatomy 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000007711 solidification Methods 0.000 description 3
- 230000008023 solidification Effects 0.000 description 3
- 229910000838 Al alloy Inorganic materials 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N Alumina Chemical compound [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 239000000919 ceramic Substances 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 230000005611 electricity Effects 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000005192 partition Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- 229910052581 Si3N4 Inorganic materials 0.000 description 1
- 239000004965 Silica aerogel Substances 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000003139 buffering effect Effects 0.000 description 1
- 210000005056 cell body Anatomy 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 239000003546 flue gas Substances 0.000 description 1
- 239000002803 fossil fuel Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 238000013021 overheating Methods 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 1
- 229910010271 silicon carbide Inorganic materials 0.000 description 1
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 238000004781 supercooling Methods 0.000 description 1
- 230000002195 synergetic effect Effects 0.000 description 1
- 238000009423 ventilation Methods 0.000 description 1
- 239000002918 waste heat Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
- C25C3/00—Electrolytic production, recovery or refining of metals by electrolysis of melts
- C25C3/06—Electrolytic production, recovery or refining of metals by electrolysis of melts of aluminium
- C25C3/08—Cell construction, e.g. bottoms, walls, cathodes
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
- C25C3/00—Electrolytic production, recovery or refining of metals by electrolysis of melts
- C25C3/06—Electrolytic production, recovery or refining of metals by electrolysis of melts of aluminium
- C25C3/20—Automatic control or regulation of cells
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
- F28D21/00—Heat-exchange apparatus not covered by any of the groups F28D1/00 - F28D20/00
Abstract
The application relates to a heat exchange system for the side part of an aluminum electrolysis cell, the aluminum electrolysis cell system and a heat balance control method, comprising a plurality of heat exchange units, wherein each heat exchange unit comprises a first heat exchanger and a second heat exchanger which are distributed up and down; the first heat exchanger comprises a first cover body, a first fan, a first air inlet and a first air outlet, wherein the first cover body is fixed on the tank shell; the air outlet of the first fan is communicated with the first air inlet; the second heat exchanger comprises a second cover body, a second fan, a second air inlet and a second air outlet, wherein the second cover body is fixed on the tank shell; the air outlet of the second fan is communicated with the second air inlet. The heat exchange system can realize the rapid and accurate regulation and control of the temperature of the side area of the aluminum cell, maintain the internal regularity of the inner wall of the aluminum cell while promoting the heat balance of the aluminum cell, and can help the aluminum cell to consume new energy power with larger current fluctuation and realize flexible operation.
Description
Technical Field
The application relates to a heat exchange system for the side part of an aluminum electrolysis cell, an aluminum electrolysis cell system and a heat balance control method, and belongs to the technical field of aluminum electrolysis.
Background
How to meet our future increasing energy demands is one of the topics that we are currently discussing worldwide. If future power generation comes mainly from renewable energy sources instead of fossil fuels, we must fundamentally change our energy utilization. Aluminum is one of the most important metals in the world today, now the second most widely used metal next to steel, and aluminum electrolysis is a high energy industry, thus also transitioning from just the end user of electricity to a "virtual battery" of the grid.
In recent years, new energy development is rapid, and the total capacity of the integrated machine is the first in the world, but new energy power generation has the characteristics of volatility, seasonality, randomness and the like. Current smelters are inflexible in terms of energy use and production because of the need to maintain the aluminium electrolysis process within a very narrow "heat balance" temperature range. When the current is increased, the temperature in the electrolytic tank is higher, and the electrolytic tank needs to be quickly cooled to prevent overheating or failure; when the current is reduced, heat preservation measures are needed to be timely taken to prevent the cooling and solidification of the metal (in the worst case, the metal production is completely lost; the cost for recovering the overall production is very high, and the time of several weeks or even months is needed). Therefore, aluminum electrolysis is required to maintain its own thermal equilibrium state while serving as a flexible load, in addition to accommodating an intermittent increase in new energy power generation.
The self-regulating capability of the aluminum electrolysis cell is limited, the process of reaching the heat balance state again only through the solidification and melting of the ledge is slow, and heat cannot be taken away timely or heat dissipation is reduced. Therefore, a reasonable heat preservation and heat dissipation measure is needed to be provided on the basis, so that heat dissipation or heat preservation can be rapidly carried out, the melting/solidification of the ledge due to overheat/supercooling is prevented, and the heat balance normal operation of the aluminum electrolysis cell is maintained.
At present, the proposed flexible operation measures of the aluminum electrolysis cell are mainly concentrated at the corresponding positions of the lateral ledge, and mainly concentrated in the aspect of heat dissipation. On one hand, the increase and the decrease of new energy electricity consumed by the aluminum electrolysis cell occur with the same probability, so that the heat preservation and the heat dissipation are important during the flexible operation of the aluminum electrolysis cell. On the other hand, the efficiency of the heat dissipation measures to the position of the shell is low only through the side ledge, when the tank is supercooled, the precipitation at the tank bottom is increased, so that the pressure drop at the tank bottom is increased, the current utilization rate is reduced, and the service life of the cathode is prolonged.
Chinese patent application publication CN105274569a discloses a forced ventilation structure of an aluminum electrolysis cell, which comprises a cell shell, a cradle frame and a cell edge board, wherein the cell shell, the cradle frame and the cell edge board form a box body, excessive heat at the side part is taken away by forced flow of gas in the box body, but the heat conductivity coefficients of the cell wall and the corresponding position of a cathode conductive metal rod are different, and the cell wall is set into a large area for heat dissipation, which is not beneficial to rationality control of the internal shape of the cell wall; and the energy consumption of the air blower is high, and the running cost is increased.
Disclosure of Invention
In view of the deficiencies of the prior art, it is an object of the present application to provide a heat exchange system for the sides of an aluminium electrolysis cell to more efficiently maintain the heat balance of the aluminium electrolysis cell; the second object of the application is to provide an aluminium electrolysis cell system; it is a further object of the present application to provide a method for controlling the heat balance of an aluminium electrolysis cell system.
In order to solve the technical problems, the technical scheme of the application is as follows:
the heat exchange system for the side part of the aluminum electrolysis cell comprises a plurality of heat exchange units, wherein the heat exchange units comprise a first heat exchanger and a second heat exchanger which are distributed up and down;
the first heat exchanger comprises a first cover body, a first fan, a first air inlet communicated with the first cover body and a first air outlet communicated with the first cover body, which are fixed on a cell shell of the aluminum electrolysis cell; the air outlet of the first fan is communicated with the first air inlet, or the air inlet of the first fan is communicated with the first air outlet; the first cover body is opened towards one side of the groove body, and a first cavity is formed by the first cover body and the groove shell in a surrounding mode;
the second heat exchanger comprises a second cover body, a second fan, a second air inlet and a second air outlet, wherein the second cover body is fixed on a cell shell of the aluminum electrolysis cell; the air outlet of the second fan is communicated with the second air inlet, or the air inlet of the second fan is communicated with the second air outlet; the second cover body is opened towards one side of the cell shell, a second cavity is formed by the second cover body and the cell shell in a surrounding mode, a window for extending out of the cathode conductive metal rod of the aluminum electrolysis cell is formed in one surface, far away from the cell shell, of the second cover body, and the window and the cathode conductive metal rod are sealed in an insulating mode.
The second heat exchanger and the first heat exchanger are respectively arranged on the cell shell near the cathode conductive metal rod and the cell shell above the cathode conductive metal rod, and the second heat exchanger and the first heat exchanger are respectively provided with an independent fan, an air inlet and an air outlet, so that the rotating speeds of the second fan and the first fan can be respectively regulated and controlled according to different heat dissipation or heat preservation requirements of different parts of the cell shell, the rapid and accurate regulation and control of the temperatures of related areas are realized, the situation that the temperatures are too high or too low in local areas is avoided, and the internal type of the internal side of the aluminum electrolysis cell is ensured while the heat balance of the aluminum electrolysis cell is realized; in addition, the rotating speed of the fan is regulated and controlled in a partition mode, the first fan and the second fan can operate at proper power, the power consumption of the fan is reduced, and the operation cost is further reduced.
Further, the first air inlet is positioned below the first air outlet; the second air inlet is positioned below the second air outlet. Optionally, an intermediate air inlet type air knife is provided at the inner bottom of the chamber in communication with the air inlet so that the air flow passes vertically upward through the heat exchanger.
Further, the distance between the first air outlet and the tank shell is greater than the distance between the first air inlet and the tank shell, and the distance between the second air outlet and the tank shell is greater than the distance between the second air inlet and the tank shell; preferably, the first cover body is in an inverted L shape, the second cover body is in an inverted L shape, and the applicant researches find that by adopting the inverted L shape cover body, vortex can be formed near the outlet of the cavity, and meanwhile, air flow has longer stay buffering time in the cavity, so that the heat dissipation uniformity and the heat dissipation efficiency can be improved.
Further, a plurality of radiating fins are arranged on the section, located in the second cavity, of the cathode conductive metal rod, the radiating fins are distributed in sequence along the length direction of the cathode conductive metal rod, and gaps are reserved between the radiating fins and the second cover body. Therefore, the heat exchange efficiency between the cathode conductive metal rod and the air in the second cavity can be further effectively improved, gaps are reserved between the radiating fins and the second cover body, insulation between the cathode conductive metal rod and the second heat exchanger can be ensured, and adverse effects on normal operation of the aluminum electrolysis cell are avoided.
Optionally, the heat dissipation fin is provided with one or more of pits, bumps and corrugations to further enhance the heat exchange effect.
Preferably, the heat dissipation fin is made of metal, and further selected from one or more of steel, aluminum alloy, pure copper and copper alloy.
Further, a heat dissipation mechanism is arranged on the groove shell corresponding to the first cover body; preferably, the heat dissipation mechanism is a heat dissipation plate paved on the tank shell, and one or more of a convex cell, a straight fin and a transverse fin are arranged on the heat dissipation plate. Therefore, the heat exchange area and the turbulence degree can be increased, and the heat exchange effect is improved. Preferably, the lateral height of the heat dissipating plate occupies 1/5-1/2 of the lateral height of the first cavity to control the air flow resistance within a reasonable range.
Further, the first heat exchanger and the second heat exchanger of the same heat exchange unit are disposed adjacent to each other.
Further, a heat insulation layer is arranged on the cover body; preferably, the heat insulation layer is made of one or more of nano aerogel, mineral wool and glass fiber. Therefore, the heat insulation between the first heat exchanger and the second heat exchanger and the external environment can be effectively improved, the accuracy of regulating and controlling the side heat balance of the aluminum electrolysis cell through the rotating speed of the fan can be further improved, and the heat preservation, heat dissipation and other various requirements are met. Alternatively, the thickness of the insulating layer is 2-12cm, further 5-10cm.
The nano aerogel has low heat conductivity coefficient and reasonable price, and can be used in combination with other materials. Preferably, the heat insulating layer covers the outer surface of the cover. Optionally, the nano aerogel is one or more of silicon-based, carbon-based, sulfur-based, metal oxide-based and metal-based aerogels; preferably, the nano aerogel is a titania doped silica aerogel.
Optionally, the cover body is made of a metal material, and further optionally one or more of steel, aluminum alloy, pure copper and copper alloy.
Further, a first temperature sensor is arranged on the outer surface of the shell area covered by the first heat exchanger, and a second temperature sensor is arranged at the first air outlet; the second cavity is internally provided with a third temperature sensor for measuring the temperature of the outer surface of the section of the cathode conductive metal rod positioned in the second cavity, and the first air outlet is provided with a fourth temperature sensor.
Optionally, the third temperature sensor is a contact temperature sensor or a non-contact temperature sensor. Preferably, when the third temperature sensor is a contact type temperature sensor, the third temperature sensor is fixed on the surface of the cathode conductive metal rod, and an insulating heat-conducting material layer is arranged between the third temperature sensor and the cathode conductive metal rod, so that electric insulation between the third temperature sensor and the cathode conductive metal rod is realized, and monitoring of temperature is not affected.
Further, a first air inlet pipe is communicated with the first air inlet, and a first air outlet pipe is communicated with the first air outlet; the second air inlet is communicated with a second air inlet pipe, and the second air outlet is communicated with a second air outlet pipe.
Preferably, the air conditioner further comprises a total air outlet pipe, and the first air outlet pipe and the second air outlet pipe are both communicated with the total air outlet pipe.
Optionally, the cathode conductive metal rod is one of a steel rod, a pure copper rod, a steel rod copper-clamping rod and a copper alloy rod.
Based on the same inventive concept, the application also provides an aluminum electrolysis cell system, which comprises an aluminum electrolysis cell and a cell controller, wherein the side part of the aluminum electrolysis cell is provided with the heat exchange system, the heat exchange units are arranged between 2 adjacent cradle frames of the aluminum electrolysis cell, and the first fan and the second fan are respectively and electrically connected with the cell controller.
Preferably, 1 heat exchange unit is arranged between every 2 adjacent cradle frames.
Optionally, the window and the cathode conductive metal rod are sealed in an insulating way through an insulating layer. Optionally, the insulating layer is formed by one or more of alumina ceramic, silicon nitride ceramic and silicon carbide ceramic.
Optionally, each temperature sensor is electrically connected with the tank controller respectively. So, the first temperature sensor and the third temperature sensor transmit the monitored temperature data to the cell controller, and the cell controller can calculate the heat dissipation capacity of the side area of the aluminum electrolysis cell; the second temperature sensor and the fourth temperature sensor transmit the monitored temperature data to the tank control machine, the tank control machine can calculate the heat exchange coefficient required by the heat exchanger according to the controllable heat balance criterion (heat dissipation capacity=heat exchange capacity), and further send operation signals to the first fan and the second fan after analysis and calculation, and the operation signals run at proper rotation speeds to control the air inlet flow of the first heat exchanger and the second heat exchanger, and adjust the heat exchange capacity so as to maintain heat balance.
Based on the same inventive concept, the application also provides a control method of heat balance of an aluminum electrolysis cell system, wherein the first heat exchanger and the second heat exchanger of the same heat exchange unit are arranged adjacently to each other, and the adjacent positions of the first heat exchanger and the second heat exchanger are positioned at the height position of the interface between aluminum liquid and cathode carbon block in the aluminum electrolysis cell; the method comprises the following steps:
calculating the heat radiation amount Q of the side area corresponding to the first heat exchanger according to (1) s ：
Optionally, the heat dissipation capacity Q is calculated by a slot control computer s ；
Calculating a first according to (2)Heat exchange quantity Q between heat exchanger and tank shell h1 ：
Optionally, the heat exchange quantity Q is calculated by a groove control computer h1 ；
Calculating h according to (3) 1 ：
Optionally, h is calculated by a slot controller 1 ；
Calculating the heat dissipation capacity Q of the side region corresponding to the second heat exchanger according to (4) c ：
Optionally, the heat dissipation capacity Q is calculated by a slot control computer c ；
Calculating the heat exchange quantity Q between the second heat exchanger and the tank shell according to the formula (5) h2 ：
Optionally, the heat exchange quantity Q is calculated by a groove control computer h2 ；
Calculating h according to (6) 1 ：
Optionally, h is calculated by a slot controller 1 ；
Controlling the angular velocity omega of the first fan 1 So that Q s ＝Q h1 ；
Controlling the angular velocity omega of the second fan 2 So that Q c ＝Q h2 ；
Optionally, through a slot controllerControlling angular velocity omega 1 Angular velocity omega 2 ；
Wherein t is n The primary crystal temperature (which can be regarded as a constant) of the electrolyte melt in the aluminum electrolysis cell; t is t c The temperature of the outer surface of the shell covered by the first heat exchanger (which can be measured in real time);
b cb the thickness of the ledge (which can be regarded as a constant) at the position corresponding to the interface between the electrolyte melt and the aluminum liquid in the aluminum electrolysis cell; b nc The thickness of the side lining (which can be regarded as a constant) at the position corresponding to the interface between the electrolyte melt and the aluminum liquid in the aluminum electrolysis cell;
λ cb thermal conductivity (can be considered as a constant) for the ledge; lambda (lambda) nc Thermal conductivity (constant) for the side liner;
h 1 effective heat transfer coefficient W.m for the covered shell to air of the first heat exchanger -2 ·K -1 ；A 1 For the total area, m, of the shell area covered by the first heat exchanger 2 ；Δt m1 Is the logarithmic average temperature difference of the inlet gas and the outlet gas in the first heat exchanger, K (K can be based on the temperature of the inlet gas (i.e. the air temperature of the environment in which the aluminum electrolysis cell is located)]And temperature calculation of the outlet gas);
t d k is the temperature (generally, the primary crystal temperature of electrolyte) of the junction of aluminum liquid, a ledge and a cathode carbon block in the aluminum electrolysis cell; t is t j K (can be obtained by real-time measurement) is the surface temperature of the section of the cathode conductive metal rod extending out of the cell shell of the aluminum electrolysis cell;
b c the thickness of the cathode carbon block, m (constant); b h The thickness, m (constant), of the cathode conductive metal rod paste; b j The thickness m (constant) of the cathode conductive metal rod in the vertical direction; l (L) j The length m (constant) of the cathode conductive metal rod positioned at the outer side of the junction of the aluminum liquid, the ledge and the cathode carbon block;
λ c is the heat conductivity coefficient W.m of the cathode carbon block -1 ·K -1 (constant); lambda (lambda) h Is the heat conductivity coefficient W.m of cathode conductive metal bar paste -1 ·K -1 (constant); lambda (lambda) j Is conductive to cathodeThermal conductivity of metal rod, W.m -1 ·K -1 (constant);
h 2 the comprehensive effective coefficient of transmission of the cathode conductive metal rod and the cell shell corresponding to the second heat exchanger to air is W.m -2 ·K -1 ；A 2 For the total area, m, of the shell area covered by the second heat exchanger 2 (constant); Δt (delta t) m2 Is the logarithmic average temperature difference of the inlet gas and the outlet gas in the second heat exchanger, K (K can be based on the temperature of the inlet gas (i.e. the air temperature of the environment in which the aluminum electrolysis cell is located)]And temperature calculation of the outlet gas);
d e1 an equivalent diameter, m (constant), of the first heat exchanger; omega 1 Rad.s for the angular velocity of the first fan -1 ；r 1 The maximum rotation radius of the wind wheel of the first fan is m (constant); alpha 1 The tip speed ratio of the wind wheel of the first fan is rad (constant, determined by the fan model);
d e2 is the equivalent diameter, m (constant), of the second heat exchanger; omega 2 Rad.s for the angular velocity of the second fan -1 ；r 2 The maximum rotation radius of the wind wheel of the second fan is m (constant); alpha 2 The tip speed ratio of the wind wheel of the second fan is rad (constant, determined by the type of the fan);
ρ is the air density in the environment of the aluminum electrolysis cell (generally, the relevant parameters in the environment of the factory where the aluminum electrolysis cell is located, the same applies below), kg.m -3 The method comprises the steps of carrying out a first treatment on the surface of the Mu is the air viscosity under the environment of the aluminum electrolysis cell, kg.m -1 ·s -1 ；C P Is the specific heat capacity J.kg of air in the environment of the aluminum electrolysis cell -1 ·K -1 。
Thus, according to the heat balance criterion Q s ＝Q h1 、Q c ＝Q h2 The rotating speeds of the first fan and the second fan are respectively adjusted, the heat exchange quantity of the first heat exchanger and the heat exchange quantity of the second heat exchanger are timely adjusted, and the aluminum electrolysis cell is timely insulated or cooled, so that the heat balance of the aluminum electrolysis cell is controlled.
The program for realizing the control method can be written into a cell control machine, and the cell control machine is used for controlling the balance between the heat dissipation capacity of the side part area of the aluminum electrolysis cell and the heat exchange capacity between the heat exchange systems, so that the heat balance of the aluminum electrolysis cell is controllable.
The connection between the heat balance of the aluminum cell and the effective heat exchange quantity of the heat exchange system at the side part is established by the cell control machine, so that the internal and external adjustment and control of the heat balance of the aluminum cell are realized, and the flexible operation of the aluminum cell is further realized.
When the current in the aluminum electrolysis cell fluctuates within a certain range (for example + -20%), for example, when the current increases or decreases, the current can be cooperatively regulated by the heat exchange system of the application to help maintain the heat balance of the electrolysis cell and maintain the flexible operation of the aluminum electrolysis cell. Therefore, by installing the heat exchange system, the aluminum electrolysis cell can be well adapted to the fluctuation of new energy power generation and maintain the self heat balance state.
Compared with the prior art, the application has the following beneficial effects:
(1) The heat exchange system can realize the rapid and accurate regulation and control of the temperature of the side area of the aluminum cell, avoid the situation that the temperature is too high or too low in the local area, promote the heat balance of the aluminum cell, maintain the internal regularity of the inner side of the aluminum cell, and help the aluminum cell to smoothly consume new energy power with larger volatility, and realize flexible operation.
(2) According to the heat exchange system, the rotating speed of the fans is regulated and controlled in a partition mode, the first fan and the second fan can operate at proper power, the power consumption of the fans is reduced, and the operation cost is further reduced.
(3) The heat exchange system can realize the control of the heat dissipation capacity of the side part of the aluminum electrolysis cell. The heat exchange system of the application realizes the adjustment and control of the heat balance of the side part by taking the control air quantity as a means.
(4) The application can realize controllable internal and external adjustment of the heat balance of the aluminum electrolysis cell by correlating the side heat exchange amount of the aluminum electrolysis cell with the side heat exchange amount of the aluminum electrolysis cell.
(5) The heat exchange system of the application has simple structure, does not need to make great modification to the aluminum electrolysis cell, is simple and convenient to install on the side cell shell of the existing aluminum electrolysis cell, can be used as a heat balance regulator on the side of the aluminum electrolysis cell provided with the heat exchange system, and overcomes the defect that the existing aluminum electrolysis cell adopts a single natural heat dissipation or heat preservation state.
(6) The surface of the cathode conductive metal rod of the aluminum electrolysis cell is provided with the radiating fins which are matched with the second heat exchanger covered on the cathode conductive metal rod to help
The rapid and efficient heat dissipation of the bottom side part of the aluminum electrolysis cell is realized.
(7) According to the application, the first heat exchanger and the second heat exchanger which are distributed up and down are arranged on the side part of the aluminum electrolysis cell, the first heat exchanger is used for radiating and preserving heat at the corresponding position of the ledge, the second heat exchanger is used for radiating and preserving heat at the bottom of the cell, and the two heat exchangers are respectively provided with independent fans, so that different gas flows are controlled according to the radiating distribution condition, and the two heat exchangers are synergistic, so that the heat balance of the electrolysis cell is maintained efficiently, and the flexible operation of the aluminum electrolysis cell is facilitated.
(8) In general, the side lining material of the aluminum cell has good heat conductivity, and the furnace side is arranged on the inner side of the cell body of the aluminum cell, which plays a vital role in material balance and heat balance in the aluminum cell; in addition, the top flue gas flow of the aluminum electrolysis cell is not well controlled, and the design of a controllable structure is difficult to be made on the basis of the existing structure. The heat exchange system is arranged on the side part of the aluminum electrolysis cell, can adjust the internal heat balance of the aluminum electrolysis cell through the external control, and has strong feasibility of designing and installing the controllable structure.
Drawings
Figure 1 is a schematic view of the heat exchange system for the side of an aluminium electrolysis cell according to a first embodiment of the application in a semi-sectional configuration.
Figure 2 is a perspective view of a heat exchange system for the side of an aluminium electrolysis cell according to the first embodiment of the application.
FIG. 3a is a schematic view showing the internal structure of a second heat exchanger according to a first embodiment of the present application; fig. 3b is an enlarged view of a cathode conductive metal rod portion in a second heat exchanger according to the first embodiment of the present application.
Fig. 4 is a schematic view showing the internal structure of several first heat exchangers according to the present application: a. a convex type heat radiation plate, b, a straight fin type heat radiation plate, c, a transverse fin type heat radiation plate.
Figure 5 is a partial cross-sectional view of an aluminium electrolysis cell according to the first embodiment of the application.
FIG. 6 is a graph comparing velocity vector distributions of an inverted "L" shaped enclosure (a) and an "I" shaped enclosure (b) of the present application.
FIG. 7 is a simulation of deformation in a ledge under the influence of the heat exchange system according to the first embodiment of the present application when the current is increased by 10%.
Detailed Description
The present application will be described in detail with reference to examples. It should be noted that, without conflict, the embodiments of the present application and features of the embodiments may be combined with each other. For convenience of description, the words "upper", "lower", "left" and "right" are used hereinafter to denote only the directions corresponding to the upper, lower, left, and right directions of the drawings, and do not limit the structure.
Referring to fig. 1, a heat exchange system for the sides of an aluminium electrolysis cell comprises a plurality of heat exchange units comprising a first heat exchanger 2 and a second heat exchanger 3 distributed up and down;
the first heat exchanger 2 comprises a first cover body fixed on a tank shell of the aluminum electrolysis tank, a first fan 7, a first air inlet communicated with the first cover body and a first air outlet communicated with the first cover body; the air outlet of the first fan 7 is communicated with the first air inlet, namely the first fan is a blower, and air is blown into the first cover body; the first cover body is opened towards one side of the groove body, and a first cavity is formed by the first cover body and the groove shell in a surrounding mode; the top surface of the first heat exchanger 2 does not exceed the top edge of the tank shell; the first air inlet and the first air outlet are both positioned on the side surface of the first cover body away from the tank shell;
the second heat exchanger 3 comprises a second cover body fixed on the cell shell of the aluminum electrolysis cell, a second fan 6, a second air inlet communicated with the second cover body and a second air outlet communicated with the second cover body; the air outlet of the second fan 6 is communicated with the second air inlet, namely the second fan is a blower, and air is blown into the second cover body; the second cover body is opened towards one side of the cell shell, a second cavity is formed by the second cover body and the cell shell, a window 304 for the cathode conductive metal rod 1 of the aluminum electrolysis cell to extend out is formed in one surface, far away from the cell shell, of the second cover body, and the window 304 and the cathode conductive metal rod 1 are sealed in an insulating mode through an insulating layer 5. The protruding end of the cathode conductive metal rod 1 is flush with the outer side wall of the second heat exchanger 3. The insulating layer is made of alumina ceramic. The second air inlet and the second air outlet are both positioned on the side surface of the second cover body away from the tank shell.
The first air inlet is positioned below the first air outlet; the second air inlet is positioned below the second air outlet. An intermediate air inlet type air knife communicated with the air inlet is arranged at the inner bottom of the cavity.
The distance between the first air outlet and the shell 12 is greater than the distance between the first air inlet and the shell 12, and the distance between the second air outlet and the shell 12 is greater than the distance between the second air inlet and the shell 12; the first cover body is in an inverted L shape, the second cover body is in an inverted L shape, at the moment, the first cavity is also in an inverted L shape, and the second cavity is also in an inverted L shape. By this arrangement, a vortex can be formed at the outlet end of the heat exchanger, so that the residence buffer time is increased, the heat dissipation at the top is more uniform, and the heat dissipation efficiency is higher, as shown in fig. 6. However, if the cover is shaped like an ordinary "I" (in this case, the cavity is shaped like a rectangular parallelepiped), the above-mentioned effects cannot be achieved, see fig. 6.
The section of the cathode conductive metal rod 1 in the second cavity is provided with a plurality of straight-fin radiating fins 303, the radiating fins 303 are distributed in sequence along the length direction of the cathode conductive metal rod 1, and gaps are reserved between the radiating fins 303 and the second cover body. 2 cathode conductive metal rods 1 are arranged between the adjacent 2 cradle frames, and the radiating fins 303 on the 2 cathode conductive metal rods 1 are not contacted with each other.
A heat dissipation mechanism is arranged on the groove shell corresponding to the first cover body; the heat dissipation mechanism is a heat dissipation plate 203 paved on the tank shell 12, and the heat dissipation plate is paved on the tank shell area surrounded by the first cover body, and optionally, one or more of a convex cell, a concave pit, a convex strip and a concave groove are arranged on the heat dissipation plate 203. The lateral height of the heat radiation plate occupies 1/3 of the lateral height of the first cavity.
The first heat exchanger 2 and the second heat exchanger 3 of the same heat exchange unit are arranged adjacent to each other. The bottom surface of the first heat exchanger 2 is level with the top surface of the cathode carbon block of the aluminum electrolysis cell; the top surface of the second heat exchanger 3 is adjacent to the bottom surface of the first heat exchanger 2; the bottom surface of the second heat exchanger 3 is flush with the turn of the shell 12.
The cover body is provided with a heat insulation layer 4; the heat insulating layer 4 is made of nano aerogel. The heat insulating layer 4 covers the outer surface of the cover.
The outer surface of the shell area covered by the first heat exchanger 2 is provided with a first temperature sensor 14, and the first air outlet is provided with a second temperature sensor 9; a third temperature sensor 10 for measuring the temperature of the outer surface of the section of the cathode conductive metal rod located in the second cavity is arranged in the second cavity, and a fourth temperature sensor 15 is arranged at the first air outlet.
The first air inlet is communicated with a first air inlet pipe 201, and the first air outlet is communicated with a first air outlet pipe 202; the second air inlet is communicated with a second air inlet pipe 301, and the second air outlet is communicated with a second air outlet pipe 302. The first fan 7 is arranged on the first air inlet pipe, and the second fan 6 is arranged on the second air inlet pipe.
The utility model also comprises a main air outlet pipe 8, and the first air outlet pipe and the second air outlet pipe are communicated with the main air outlet pipe. Therefore, the gas after heat exchange in the first heat exchanger and the second heat exchanger is converged into the main gas outlet pipe 8, and the subsequent waste heat utilization can be facilitated.
An aluminium electrolysis cell system comprising an aluminium electrolysis cell and a cell control machine, the side of the aluminium electrolysis cell being provided with a heat exchange system as described above, the heat exchange units being arranged between 2 adjacent cradle racks 13 of the aluminium electrolysis cell. Each side of the aluminium electrolysis cell is provided with 1 heat exchange unit between every 2 adjacent cradle frames 13.
The aluminum electrolysis cell is matched with a cell control machine 11, and a first temperature sensor 14, a second temperature sensor 9, a third temperature sensor 10 and a fourth temperature sensor 15 are respectively and electrically connected with the cell control machine 11; the first fan 7 and the second fan 6 are respectively and electrically connected with the slot controller 11.
According to the control method for the heat balance of the aluminum electrolysis cell, the bottom surface of the first heat exchanger and the top surface of the second heat exchanger of the same heat exchange unit are arranged adjacently, the adjacent positions of the first heat exchanger and the second heat exchanger are positioned at the height position of the interface between aluminum liquid and cathode carbon blocks in the aluminum electrolysis cell, the top surface of the first heat exchanger is level with the top edge of the cell shell, and the bottom surface of the second heat exchanger is level with the bottom edge of the cell shell; the method comprises the following steps:
calculating the heat dissipation quantity Q of the side area corresponding to the first heat exchanger according to the formula (1) through the groove control machine s ：
Calculating the heat exchange quantity Q between the first heat exchanger and the tank shell according to the formula (2) through the tank control machine h1 ：
Calculating h according to the formula (3) through a groove control machine 1 ：
Calculating the heat dissipation quantity Q of the side area corresponding to the second heat exchanger according to the formula (4) through the groove control machine c ：
Calculating the heat exchange quantity Q between the second heat exchanger and the tank shell according to the mode (5) through the tank control machine h2 ：
Calculating h according to the formula (6) through a groove control machine 1 ：
Angular velocity omega of first fan controlled by groove control machine 1 So that Q s ＝Q h1 ；
Angular velocity omega of second fan is controlled by groove control machine 2 So that Q c ＝Q h2 ；
Wherein t is n The primary crystal temperature of the electrolyte melt 20 in the aluminum electrolysis cell; t is t c A temperature of an outer surface of the shell covered by the first heat exchanger;
b cb the thickness of the ledge at the position corresponding to the interface between the electrolyte melt 20 and the aluminum liquid 19 in the aluminum electrolysis cell; b nc The thickness of the side lining 16 at the position corresponding to the interface between the electrolyte melt and the aluminum liquid in the aluminum electrolysis cell;
λ cb is the thermal conductivity of ledge 22; lambda (lambda) nc Is the thermal conductivity of the side liner 16;
h 1 an effective heat transfer coefficient to air for the covered shell of the first heat exchanger; a is that 1 A total area of the shell area covered by the first heat exchanger; Δt (delta t) m1 The logarithmic average temperature difference of the inlet and outlet gases in the first heat exchanger;
t d is the temperature of the junction of the aluminum liquid 19, the ledge 22 and the cathode carbon block 18 in the aluminum electrolysis cell; t is t j The surface temperature of the section of the cathode conductive metal rod extending out of the cell shell of the aluminum electrolysis cell;
b c is the thickness of the cathode carbon block 18; b h A thickness of the cathode conductive metal bar paste 17; b j The thickness of the cathode conductive metal rod 1 in the vertical direction; l (L) j The length of the cathode conductive metal rod 1 positioned outside the juncture of the aluminum liquid, the ledge 22 and the cathode carbon block 18;
λ c the heat conductivity coefficient of the cathode carbon block; lambda (lambda) h The heat conductivity coefficient of the cathode conductive metal rod paste; lambda (lambda) j The heat conductivity coefficient of the cathode conductive metal rod;
h 2 the cathode conductive metal rod and the cell shell corresponding to the second heat exchanger are used for comprehensively and effectively transmitting coefficients to air; a is that 2 A total area of the shell area covered by the second heat exchanger; Δt (delta t) m2 The logarithmic average temperature difference of the inlet and outlet gases in the second heat exchanger;
d e1 is the equivalent diameter of the first heat exchanger; omega 1 Is the angular velocity of the first fan; r is (r) 1 The maximum rotation radius of the wind wheel of the first fan; alpha 1 The tip speed ratio of the wind wheel of the first fan;
d e2 is the equivalent diameter of the second heat exchanger; omega 2 Is the angular velocity of the second fan; r is (r) 2 The maximum rotation radius of the wind wheel of the second fan; alpha 2 The tip speed ratio of the wind wheel of the second fan;
ρ is the air density of the aluminum electrolysis cell in the environment; mu is the air viscosity of the aluminum electrolysis cell in the environment; c (C) P The specific heat capacity of air in the environment of the aluminum electrolysis cell is obtained.
The rotation speeds of the first fan and the second fan are regulated through the cell control machine, so that the air inlet flow of the first heat exchanger and the air inlet flow of the second heat exchanger are controlled, the heat exchange efficiency of the related heat exchanger is regulated, and the side part of the aluminum electrolysis cell is subjected to heat preservation or heat dissipation. Specifically, the slot controller 11 is based on a thermal balance criterion: q (Q) s ＝Q h1 、Q c ＝Q h2 When the heat balance in the aluminum electrolysis cell is destroyed, different rotating speed adjusting signals are respectively sent to the first fan and the second fan according to the corresponding relation between the heat balance in the aluminum electrolysis cell and the heat exchange coefficients of the first heat exchanger and the second heat exchanger, and the rotating speed of the fans is adjusted in real time according to the required heat exchange coefficient value and the inlet and outlet air temperature feedback value. For example, when the input current of the aluminum electrolysis cell increases, the heat balance in the aluminum electrolysis cell is destroyed, the cell controller 11 responds to the operation and respectively sends control signals for increasing the rotation speed to the first heat exchanger and the second heat exchanger, the rotation speed of the fan increases, the heat exchange air flow in the heat exchanger increases, the heat exchange efficiency greatly increases, the heat conductivity coefficient of the position of the cathode conductive metal rod is better, and correspondingly the rotation speed of the second fan at the bottom is slightly larger, and the second fan is taken awayThe more heat. The first heat exchanger and the second heat exchanger work cooperatively so that the excessive heat of the aluminum electrolysis cell can be quickly carried away, and the heat balance of the electrolysis cell is maintained. On the contrary, when the input current of the aluminum electrolysis cell is reduced, the cell control machine 11 respectively sends control signals of rotating speed reduction to the first heat exchanger and the second heat exchanger, meanwhile, as the heat conductivity of air staying in the heat exchangers is lower, the heat insulation layer is arranged outside the cover body, and the double-layer heat insulation of the air and the heat insulation layer ensures that the heat balance of the electrolysis cell can be controlled when the current is reduced, and at the moment, the rotating speed of the fan is only regulated according to the fluctuation of the heat balance, so that the heat insulation effect of the aluminum electrolysis cell is regulated.
When the input current of the aluminum electrolysis cell is increased by 10 percent (taking 420kA aluminum electrolysis cell as an example), modeling simulation calculation of a slice model is carried out on the structure, and according to the simulation calculation, the cell shell temperature t of the corresponding position of the first heat exchanger is increased by 10 percent c Primary crystal temperature t of electrolyte =395℃ n Ledge thickness b at 940 = cb =0.09 m, coefficient of thermal conductivity λ cb ＝1.29W·m -1 ·K -1 Side liner thickness b nc =0.186 m, and the calculation formula of the multi-layer heat transfer coefficient of heat conductivity obtains the equivalent heat transfer coefficient lambda of the side lining nc ＝4.179W·m -1 ·K -1 The method comprises the steps of carrying out a first treatment on the surface of the The inlet air temperature of the heat exchanger is 25 ℃, the outlet air temperature is 255 ℃, and the logarithmic average temperature difference delta t is obtained m1 = 202.265K, and then by Q s ＝Q h1 Obtaining the effective heat exchange coefficient h of the heat exchanger required for heat dissipation 1 ＝23.578W·m -2 ·K -1 。
Surface temperature t of cathode conductive metal rod extending from second heat exchanger cover j Primary crystal temperature t =395 DEG C d Cathode carbon block thickness b =940℃ c Thickness b of cathode conductive metal rod paste =0.665 m h Thickness b of cathode conductive metal rod in vertical direction =0.015 m j ＝0.1m，L j Heat conductivity coefficient λ of cathode carbon block=0.426 m c ＝12.6W·m -1 ·K -1 Thermal conductivity coefficient lambda of cathode conductive metal rod paste h ＝4.74W·m -1 .K -1 Conductive metal rod of cathodeCoefficient of thermal lambda j ＝33.75W·m -1 ·K -1 The method comprises the steps of carrying out a first treatment on the surface of the The inlet air temperature of the heat exchanger is 25 ℃, the outlet air temperature is 150 ℃, and the logarithmic average temperature difference delta t is obtained m1 = 239.198K, and then by Q c ＝Q h2 Obtaining the effective heat exchange coefficient h of the heat exchanger required for heat dissipation 2 ＝20.0318W·m -2 ·k -1 。
The equivalent diameters of the side controllable rectangular heat exchangers established by simulation are all 0.286m, and the related air property parameters are respectively air heat conductivity coefficient lambda= 0.03931W.m -1 ·K -1 Density ρ=0.746 kg·m -3 Viscosity μ=2.6x10 - 5 kg·m -1 ·s -1 Specific heat capacity C P ＝1.034×10 3 J·kg -1 ·K -1 Further calculating according to formulas (3) and (6) to obtain gas flow velocity V 1 ＝10.213m/s、V 2 The wind wheels of the first fan and the second fan are 3-blade wind wheels, the tip speed ratio of the wind wheels is 4, the maximum rotation radius of the wind wheels is 12.47cm, and then according to the following conditionsThe calculation shows that the angular velocity omega of the first fan 1 At 327.6rad/s, the angular velocity ω of the second fan 2 267.233rad/s.
The heat insulating layer adopts the material property of nanometer aerogel, the cathode conductive metal rod and the radiating fins on the surface of the cathode conductive metal rod, the heat exchange plate of the upper heat exchanger adopts the material property of pure copper, and the heat exchanger shell adopts the material property of the side cradle. As shown in FIG. 7, after the input current is increased by 10%, the inner contour line of the ledge changes to the position shown by a white dotted line, at this time, the first fan and the second fan are operated at the angular speed, after heat dissipation for 2 hours, the ledge changes from the position shown by the white dotted line to the position shown by a white solid line, the ledge becomes thick and returns to normal, and the side heat dissipation capacity is controlled by the heat exchange system and the control method, so that the heat balance of the electrolytic tank is maintained, and the regular inner shape of the ledge is maintained.
According to the simulation experiment, the heat exchange system has feasibility in the aspect of regulating and controlling the heat balance of the aluminum electrolysis cell and realizing flexible operation of the electrolysis cell. The foregoing examples are set forth in order to provide a more thorough description of the present application and are not intended to limit the scope of the application, and various modifications of the application, which are equivalent to those skilled in the art upon reading the present application, will fall within the scope of the application as defined in the appended claims.
Claims (10)
1. The heat exchange system for the side part of the aluminum electrolysis cell is characterized by comprising a plurality of heat exchange units, wherein the heat exchange units comprise a first heat exchanger (2) and a second heat exchanger (3) which are distributed up and down;
the first heat exchanger (2) comprises a first cover body, a first fan (7), a first air inlet communicated with the first cover body and a first air outlet communicated with the first cover body, wherein the first cover body is fixed on a tank shell of the aluminum electrolysis tank; the air outlet of the first fan (7) is communicated with the first air inlet, or the air inlet of the first fan (7) is communicated with the first air outlet; the first cover body is open towards one side of the groove body,
the first cover body and the groove shell enclose a first cavity;
the second heat exchanger (3) comprises a second cover body, a second fan (6), a second air inlet communicated with the second cover body and a second air outlet communicated with the second cover body, wherein the second cover body is fixed on a tank shell of the aluminum electrolysis tank; the air outlet of the second fan (6) is communicated with a second air inlet, or the air inlet of the second fan (6) is communicated with a second air outlet; the second cover body is opened towards one side of the groove shell,
the second cavity is enclosed by the second cover body and the cell shell, a window (304) for the cathode conductive metal rod (1) of the aluminum electrolysis cell to extend out is formed in one surface, far away from the cell shell, of the second cover body, and the window (304) is insulated and sealed with the cathode conductive metal rod (1).
2. The heat exchange system of claim 1, wherein the first air inlet is located below the first air outlet; the second air inlet is positioned below the second air outlet.
3. The heat exchange system of claim 2, wherein a distance between the first air outlet and the shell (12) is greater than a distance between the first air inlet and the shell (12), and a distance between the second air outlet and the shell (12) is greater than a distance between the second air inlet and the shell (12); preferably, the first cover body is in an inverted L shape, and the second cover body is in an inverted L shape.
4. The heat exchange system according to claim 1, wherein a plurality of heat radiating fins (303) are provided on a section of the cathode conductive metal rod (1) located in the second cavity, the plurality of heat radiating fins (303) are distributed in sequence along the length direction of the cathode conductive metal rod (1), and gaps are left between each heat radiating fin (303) and the second cover.
5. The heat exchange system according to claim 1, wherein the heat dissipation mechanism is provided on the tank shell corresponding to the first cover; preferably, the heat dissipation mechanism is a heat dissipation plate (203) paved on the tank shell (12), and one or more of a convex cell, a concave pit, a convex strip and a concave groove are arranged on the heat dissipation plate (203).
6. A heat exchange system according to any one of claims 1-5, characterized in that the first heat exchanger (2) and the second heat exchanger (3) of the same heat exchange unit are arranged adjacent to each other.
7. Heat exchange system according to any one of claims 1-5, wherein the cover is provided with a heat insulating layer (4); preferably, the heat insulation layer (4) is made of one or more of nano aerogel, mineral wool and glass fiber; preferably, the insulating layer (4) covers the outer surface of the cover.
8. A heat exchange system according to any one of claims 1-5, wherein the outer surface of the shell area covered by the first heat exchanger (2) is provided with a first temperature sensor (14), and the first air outlet is provided with a second temperature sensor (9); a third temperature sensor (10) for measuring the temperature of the outer surface of the section of the cathode conductive metal rod positioned in the second cavity is arranged in the second cavity, and a fourth temperature sensor (15) is arranged at the first air outlet.
9. An aluminium electrolysis cell system comprising an aluminium electrolysis cell and a cell control machine (11), characterized in that the side of the aluminium electrolysis cell is provided with a heat exchange system according to any one of claims 1-8, the heat exchange units being arranged between 2 adjacent cradle racks (13) of the aluminium electrolysis cell; the first fan (7) and the second fan (6) are respectively and electrically connected with the groove control machine (11).
10. The method for controlling the heat balance of an aluminum electrolysis cell system according to claim 9, wherein the first heat exchanger and the second heat exchanger of the same heat exchange unit are arranged adjacently to each other, and the adjacent positions of the first heat exchanger and the second heat exchanger are positioned at the height position of the interface between the aluminum liquid and the cathode carbon block in the aluminum electrolysis cell; the method comprises the following steps:
calculating the heat radiation amount Q of the side area corresponding to the first heat exchanger according to (1) s ：
Calculating the heat exchange quantity Q between the first heat exchanger and the tank shell according to the formula (2) h1 ：
Calculating h according to (3) 1 ：
Calculating the heat dissipation capacity Q of the side region corresponding to the second heat exchanger according to (4) c ：
Calculating the heat exchange quantity Q between the second heat exchanger and the tank shell according to the formula (5) h2 ：
Calculating h according to (6) 2 :
Controlling the angular velocity omega of the first fan 1 So that Q s ＝Q h1 ；
Controlling the angular velocity omega of the second fan 2 So that Q c ＝Q h2 ；
Wherein t is n The primary crystal temperature of the electrolyte melt in the aluminum electrolysis cell; t is t c A temperature of an outer surface of the shell covered by the first heat exchanger;
b cb the thickness of the ledge at the corresponding position of the interface between the electrolyte melt and the aluminum liquid in the aluminum electrolysis cell; b nc The thickness of the side lining at the position corresponding to the interface between the electrolyte melt and the aluminum liquid in the aluminum electrolysis cell;
λ cb the thermal conductivity of the ledge; lambda (lambda) nc The thermal conductivity of the side lining;
h 1 an effective heat transfer coefficient to air for the covered shell of the first heat exchanger; a is that 1 A total area of the shell area covered by the first heat exchanger; Δt (delta t) m1 The logarithmic average temperature difference of the inlet and outlet gases in the first heat exchanger;
t d is the temperature of the juncture of the aluminum liquid, the ledge and the cathode carbon block in the aluminum electrolysis cell; t is t j For cathode conductive metal rods extending outside the casing of the aluminium cellSurface temperature of the segment;
b c the thickness of the cathode carbon block; b h The thickness of the cathode conductive metal bar paste; b j The thickness of the cathode conductive metal rod in the vertical direction; l (L) j The length of the cathode conductive metal rod positioned outside the junction of the aluminum liquid, the ledge and the cathode carbon block;
λ c the heat conductivity coefficient of the cathode carbon block; lambda (lambda) h The heat conductivity coefficient of the cathode conductive metal rod paste; lambda (lambda) j The heat conductivity coefficient of the cathode conductive metal rod;
h 2 the cathode conductive metal rod and the cell shell corresponding to the second heat exchanger are used for comprehensively and effectively transmitting coefficients to air; a is that 2 A total area of the shell area covered by the second heat exchanger; Δt (delta t) m2 The logarithmic average temperature difference of the inlet and outlet gases in the second heat exchanger;
d e1 is the equivalent diameter of the first heat exchanger; omega 1 Is the angular velocity of the first fan; r is (r) 1 The maximum rotation radius of the wind wheel of the first fan; alpha 1 The tip speed ratio of the wind wheel of the first fan;
d e2 is the equivalent diameter of the second heat exchanger; omega 2 Is the angular velocity of the second fan; r is (r) 2 The maximum rotation radius of the wind wheel of the second fan; alpha 2 The tip speed ratio of the wind wheel of the second fan;
ρ is the air density of the aluminum electrolysis cell in the environment; mu is the air viscosity of the aluminum electrolysis cell in the environment; c (C) P The specific heat capacity of air in the environment of the aluminum electrolysis cell is obtained.
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