Energy Management System and Control Methods for Aluminum Plants

Abstract

This application relates to an energy management system and control method for an aluminum plant. The energy management system includes an energy storage circuit, an energy release circuit, a first thermal energy storage circuit, and a second thermal energy storage circuit. The energy storage circuit drives the circulation of the energy storage medium and converts electrical energy into thermal energy of the energy storage medium. The first thermal energy storage circuit drives the circulation of a first thermal energy storage medium and supplies heat to the aluminum plant's production. The first thermal energy storage circuit is connected to the energy storage circuit via a first heat exchanger. The energy release circuit drives the circulation of the energy release medium and converts the thermal energy of the energy release medium into electrical energy for use in the aluminum plant's production. The energy release circuit is connected to the first thermal energy storage circuit via a second heat exchanger. The second thermal energy storage circuit drives the circulation of a second thermal energy storage medium and recovers waste heat from the aluminum plant's production. The second thermal energy storage circuit is connected to the energy storage circuit via a third heat exchanger, and the second thermal energy storage circuit is connected to the energy release circuit via a fourth heat exchanger.

Description

Technical Field

[0001] This application relates to the field of energy management technology in aluminum plants, and in particular to an energy management system and control method for aluminum plants. Background Technology

[0002] As energy-intensive enterprises, aluminum plants are consistently major electricity consumers in their respective regions. Currently, most aluminum plants convert AC mains power to DC power to supply their electrolytic aluminum production lines, with electricity costs accounting for approximately 30% of total costs. Furthermore, the upstream processes in the electrolytic aluminum production line, such as alumina leaching and roasting, require significant amounts of heat energy and generate substantial waste heat. Inadequate heat energy planning leads to energy waste and further increases costs.

[0003] However, the relevant technologies only improve the high-power-consuming electrolytic aluminum process without addressing the effective planning of the overall thermal and electrical energy of the aluminum plant, resulting in high production energy consumption and increased production costs. Summary of the Invention

[0004] Therefore, it is necessary to provide an energy management system and control method for aluminum plants to address the issue of how to rationally manage the overall thermal and electrical energy of aluminum plants and reduce energy consumption and costs.

[0005] In a first aspect, this application provides an energy management system for an aluminum plant, comprising:

[0006] An energy storage circuit is used to drive the energy storage medium to circulate and can convert electrical energy into thermal energy of the energy storage medium.

[0007] The first thermal storage circuit is used to drive the circulation of the first thermal storage medium and supply heat to the aluminum plant for production. The first thermal storage circuit is in heat exchange cooperation with the energy storage circuit through the first heat exchanger.

[0008] An energy release circuit is used to drive the energy release working medium to circulate and convert the thermal energy of the energy release working medium into electrical energy for use in aluminum plant production. The energy release circuit is in heat exchange cooperation with the first heat storage circuit through a second heat exchanger.

[0009] The second thermal storage circuit is used to drive the second thermal storage medium to circulate and recover the waste heat from the aluminum plant. The second thermal storage circuit is in heat exchange cooperation with the energy storage circuit through a third heat exchanger, and the second thermal storage circuit is in heat exchange cooperation with the energy release circuit through a fourth heat exchanger.

[0010] The energy management system of the aluminum plant has alternating energy storage and energy release modes:

[0011] In the energy storage mode, the energy storage circuit drives the energy storage medium to circulate and converts electrical energy into thermal energy of the energy storage medium; the first thermal storage circuit drives the first thermal storage medium to acquire the thermal energy of the energy storage medium in the first heat exchanger and stores and / or supplies the thermal energy to the aluminum plant for production; the second thermal storage circuit drives the second thermal storage medium to recover the waste heat from the aluminum plant's production and supply heat to the energy storage medium in the third heat exchanger, while preheating the air used in the aluminum plant's production.

[0012] In the energy release mode, the first thermal storage circuit drives the first thermal storage medium to provide heat for the aluminum plant's production and to provide heat to the energy release medium in the second heat exchanger; the energy release circuit drives the energy release medium to convert thermal energy into electrical energy for the aluminum plant's production and generates waste heat for the aluminum plant's production; the second thermal storage circuit drives the second thermal storage medium to recover the aluminum plant's production waste heat and to recover the energy release medium's power generation waste heat in the fourth heat exchanger, while preheating the air used in the aluminum plant's production.

[0013] The technical solution will be further explained below:

[0014] In one embodiment, the energy storage circuit includes:

[0015] An electric motor, used for electrical connection to green electricity;

[0016] A first compressor is electrically connected to the electric motor, and the first compressor is capable of compressing the energy storage medium under the drive of the electric motor;

[0017] A first expander is coaxially arranged with the first compressor, and the first expander can rotate under the drive of the energy storage working fluid;

[0018] The first pipeline has one end connected to the medium outlet of the first compressor, and the other end connected to the medium inlet of the first expander after passing through the first heat exchanger.

[0019] The second pipeline is connected to the medium outlet of the first expander, and the other end of the second pipeline is connected to the medium inlet of the first compressor after passing through the third heat exchanger.

[0020] In one embodiment, the energy storage loop further includes a fifth heat exchanger, and the first pipeline between the first heat exchanger and the medium inlet of the first expander is heat-exchange coupled with the second pipeline between the fifth heat exchanger and the medium inlet of the first expander.

[0021] In one embodiment, the first heat storage return includes:

[0022] The first storage tank is used to store the first heat storage medium;

[0023] The second storage tank is used to store the first heat storage medium, and the temperature of the first heat storage medium in the first storage tank is lower than the temperature of the first heat storage medium in the second storage tank.

[0024] A third pipeline, one end of which is connected to the medium outlet of the first storage tank, and the other end of which is connected to the medium inlet of the second storage tank after passing through the first heat exchanger, and a first medium pump is provided on the third pipeline;

[0025] The fourth pipeline has one end connected to the first medium outlet of the second storage tank and the other end connected to the first medium inlet of the first storage tank. A second medium pump is installed on the fourth pipeline, which is used to supply heat to the production line of the aluminum plant.

[0026] The fifth pipeline has one end connected to the second medium outlet of the second storage tank, and the other end connected to the second medium inlet of the first storage tank after passing through the second heat exchanger. A third medium pump is provided on the fifth pipeline.

[0027] In one embodiment, the first heat storage return also includes:

[0028] A sixth heat exchanger, connected to the fourth pipeline, is used to connect to the steam circulation system of the aluminum plant's leaching process to heat the condensate generated by the steam circulation system; and / or,

[0029] The seventh heat exchanger is connected to the fourth pipeline and is used to connect to the air channel of the calcination process of the aluminum plant to preheat the air required for the calcination process.

[0030] In one embodiment, the second thermal storage circuit includes:

[0031] The third storage tank is used to store the second heat medium;

[0032] The fourth storage tank is used to store the second heat storage medium, and the temperature of the second heat storage medium in the third storage tank is lower than the temperature of the second medium in the fourth storage tank.

[0033] The sixth pipeline has one end connected to the medium outlet of the third storage tank, and the other end connected to the medium inlet of the fourth storage tank after passing through the fourth heat exchanger.

[0034] The seventh pipeline has one end connected to the medium outlet of the third storage tank and the other end connected to the medium inlet of the fourth storage tank. The seventh pipeline is used to recover waste heat from the aluminum plant's production.

[0035] The eighth pipeline has one end connected to the medium outlet of the fourth storage tank, and the other end connected to the medium inlet of the third storage tank after passing through the third heat exchanger.

[0036] The third storage tank is connected to a fourth medium pump at its medium outlet; the fourth storage tank is connected to a fifth medium pump at its medium outlet.

[0037] In one embodiment, the second heat storage return also includes:

[0038] An eighth heat exchanger, connected to the seventh pipeline, is used to connect to the flue gas pipeline of the aluminum plant's roasting process to recover waste heat from the flue gas of the roasting process; and / or,

[0039] A ninth heat exchanger, connected to the seventh pipeline, is used to connect to the flue gas pipeline of the aluminum plant's electrolytic aluminum production line to recover waste heat from the flue gas of the electrolytic aluminum production line; and / or,

[0040] The tenth heat exchanger is connected to the eighth pipeline and is arranged in parallel with the third heat exchanger. The tenth heat exchanger is used to connect to the air channel of the calcination process of the aluminum plant to preheat the air required for the calcination process.

[0041] In one embodiment, the energy release circuit includes:

[0042] The second expander is capable of rotating under the drive of the energy-releasing working medium to convert the thermal energy of the energy-releasing working medium into mechanical energy;

[0043] The second compressor is coaxially arranged with the second expander, and the second compressor can rotate and compress the energy-releasing working fluid under the drive of the second expander;

[0044] A generator connected to the second compressor, the generator being able to rotate under the drive of the second compressor to convert mechanical energy into electrical energy and supply it to the aluminum plant production line;

[0045] The ninth pipeline has one end connected to the medium outlet of the second compressor, and the other end connected to the medium inlet of the second expander after passing through the second heat exchanger.

[0046] The tenth pipeline has one end connected to the medium outlet of the second expander and the other end connected to the medium inlet of the second compressor after passing through the fourth heat exchanger.

[0047] In one embodiment, the energy release loop further includes an eleventh heat exchanger, which is connected to the tenth pipeline and connected in series with the fourth heat exchanger. The eleventh heat exchanger is located upstream of the fourth heat exchanger and is used to connect to the steam circulation system of the aluminum plant's leaching process to heat the condensate generated by the steam circulation system.

[0048] Secondly, this application also provides an energy control method for an aluminum plant, which is implemented using the aforementioned aluminum plant energy management system. The energy control method for the aluminum plant includes an energy storage mode and an energy release mode.

[0049] The energy storage mode includes the following steps:

[0050] The aluminum plant's electrolytic aluminum production line is connected to the mains power, and the energy storage circuit uses green electricity for direct connection;

[0051] The energy storage circuit drives the energy storage medium to circulate and converts the electrical energy of the green electricity into the thermal energy of the energy storage medium;

[0052] The first thermal storage circuit drives the first thermal storage medium to circulate, so that the first thermal storage medium can acquire the thermal energy of the energy storage medium in the first heat exchanger, and store and / or supply the thermal energy to the aluminum plant for production.

[0053] The second thermal storage circuit drives the second thermal storage medium to circulate, so that the second thermal storage medium recovers the waste heat from the aluminum plant's production and supplies heat to the energy storage medium in the third heat exchanger, while preheating the air used in the aluminum plant's production.

[0054] The energy release mode includes the following steps:

[0055] The aluminum plant's electrolytic aluminum production line is disconnected from the mains power and connected to the energy release circuit, while the energy storage circuit is disconnected from the green electricity.

[0056] The first thermal storage circuit drives the first thermal storage medium to circulate, providing heat for aluminum plant production and for the energy-releasing working fluid in the second heat exchanger.

[0057] The energy release circuit drives the energy release working medium to circulate, so as to convert the thermal energy of the energy release working medium into electrical energy and supply it to the electrolytic aluminum production line, while generating waste heat for the aluminum plant to use in production.

[0058] The second thermal storage circuit drives the second thermal storage medium to circulate, so that the second thermal storage medium recovers the waste heat from the aluminum plant's production and recovers the waste heat from the power generation of the energy-releasing working medium in the fourth heat exchanger, while preheating the air used in the aluminum plant's production.

[0059] In the energy storage mode, the aforementioned aluminum plant energy management system converts electrical energy into heat energy through energy storage loops. The first heat storage loop can acquire and store the heat energy of the energy storage loop in the first heat exchanger for use in aluminum plant production. The second heat storage loop can recover and store the waste heat from aluminum plant production to supplement the heat energy of the energy storage loop in the third heat exchanger. In the energy release mode, the first heat storage loop not only supplies the stored heat energy to aluminum plant production but also supplies it to the energy release loop in the third heat exchanger. The energy release loop acquires the heat energy from the first heat storage loop and converts it into electrical energy for use in aluminum plant production. In addition to recovering and storing the waste heat from aluminum plant production, the second heat storage loop can also recover and store the waste heat generated by the energy release loop in the fourth heat exchanger. This achieves the coupling of the energy storage power generation system with the aluminum plant's production line, forming a comprehensive energy management system for the aluminum plant. On the one hand, during periods of low grid electricity demand or when grid electricity prices are low, the aluminum plant's energy management system can switch to energy release mode; during periods of high grid electricity demand or when grid electricity prices are high, the system switches back to energy release mode, thus enabling rational planning of electricity consumption based on peak and off-peak electricity prices and saving electricity costs. On the other hand, the first thermal storage loop supplies heat to the aluminum plant, while the second thermal storage loop recovers waste heat from the plant's production, achieving cascaded utilization of thermal energy and reducing production energy consumption. Attached Figure Description

[0060] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application.

[0061] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0062] Furthermore, the accompanying drawings are not drawn to a 1:1 scale, and the relative dimensions of the various components are shown as examples only and not necessarily to scale. In the accompanying drawings:

[0063] Figure 1 This is a wireframe diagram of an energy management system for an aluminum plant, as shown in one embodiment.

[0064] Figure 2 for Figure 1 The diagram shows a wireframe representation of the energy management system of an aluminum plant in energy storage mode.

[0065] Figure 3 for Figure 1 The diagram shows a wireframe representation of the energy management system of an aluminum plant in energy release mode.

[0066] Explanation of reference numerals in the attached figures:

[0067] 11. Electric motor; 12. First compressor; 13. First expander; 14. First pipeline; 15. Second pipeline; 21. First storage tank; 22. Second storage tank; 23. Third pipeline; 231. First medium pump; 24. Fourth pipeline; 241. Second medium pump; 25. Fifth pipeline; 251. Third medium pump; 31. Third storage tank; 32. Fourth storage tank; 33. Sixth pipeline; 34. Seventh pipeline; 341. Fourth medium pump; 35. Eighth pipeline; 351. Fifth medium pump; 41. Second expander; 42. Second compressor; 43. Ninth Piping; 44. Tenth Piping; 45. Generator; 51. Alumina Production Line; 511. Leaching Process; 512. Other Processes; 513. Calcination Process; 52. Electrolytic Aluminum Production Line; 61. First Converter; 62. Second Converter; 71. Mains Power; 72. Green Power; 81. First Heat Exchanger; 82. Second Heat Exchanger; 83. Third Heat Exchanger; 84. Fourth Heat Exchanger; 85. Fifth Heat Exchanger; 86. Sixth Heat Exchanger; 87. Seventh Heat Exchanger; 88. Eighth Heat Exchanger; 89. Ninth Heat Exchanger; 810. Tenth Heat Exchanger; 811. Eleventh Heat Exchanger. Detailed Implementation

[0068] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0069] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0070] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0071] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0072] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0073] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0074] See Figure 1 , Figure 1 A schematic diagram of the structure of an aluminum plant energy management system according to an embodiment of this application is shown. To facilitate understanding of the aluminum plant energy management system of this application embodiment, a brief introduction to some production lines of the aluminum plant involved in this application is provided first. For example... Figure 1The aluminum plant includes an alumina production line 51 and an electrolytic aluminum production line 52. Bauxite, after being converted into alumina in the alumina production line 51, enters the electrolytic aluminum production line 52 for electrolysis to obtain pure aluminum. The alumina production line 51 includes a leaching process 511, a roasting process 513, and other processes 512 between the leaching and roasting processes 511 and 513. Specifically, the leaching process 511 requires heating via a steam circulation system, and the roasting process 513 requires preheated air to mix with fuel gas for combustion heating. The condensate heating of the steam circulation system in the leaching process 511 and the air preheating in the roasting process 513 both require a large amount of heat energy. Simultaneously, the roasting process 513 generates flue gas with a large amount of waste heat. The electrolytic aluminum production line 52 needs to be connected to the mains power supply 71. The mains power supply 71 converts AC power to DC power through a first converter 61 to supply power to the electrolytic aluminum production line 52. Similarly, the electrolytic aluminum production line 52 also generates flue gas with a large amount of waste heat.

[0075] As mentioned in the background and related technologies, most of them only focus on process improvements for the high-power-consuming electrolytic aluminum production line 52, without addressing the effective planning of the overall thermal and electrical energy of the aluminum plant, resulting in high production energy consumption and increased production costs.

[0076] Based on this, one embodiment of this application provides an energy management system for an aluminum plant, specifically, see [link to relevant documentation]. Figure 1 It includes an energy storage circuit, an energy release circuit, a first thermal storage circuit, and a second thermal storage circuit.

[0077] The energy storage circuit drives the circulation of the energy storage medium and converts electrical energy into thermal energy. Specifically, the energy storage circuit can be directly connected to a green electricity source, thereby converting the low-quality green electricity into stable thermal energy of the energy storage medium. For example, the energy storage medium can be gases such as air, carbon dioxide, argon, or helium.

[0078] The first thermal storage circuit is used to drive the circulation of the first thermal storage medium and supply heat to the aluminum plant's production processes. For example, it heats the condensate in the circulation system of the leaching process 511 into steam for use in the leaching process 511, and preheats the air required in the calcination process 513. Further, the first thermal storage circuit is connected to the energy storage circuit via a first heat exchanger 81, allowing the first thermal storage medium to acquire thermal energy from the energy storage medium in the first heat exchanger 81. Specifically, the first thermal storage medium can store thermal energy for use in the aluminum plant's production and for power generation in the energy release circuit. For example, the first thermal storage medium can be molten salt, heat transfer oil, etc.

[0079] The energy release circuit is used to drive the circulation of the energy-releasing working medium and convert its thermal energy into electrical energy for use in aluminum plant production, such as for electrolytic aluminum production line 52. The energy release circuit is connected to the first heat storage circuit via a second heat exchanger 82, allowing the energy-releasing working medium to acquire thermal energy from the first heat storage medium in the second heat exchanger 82 for power generation. For example, the energy-releasing working medium can be gases such as air, carbon dioxide, argon, or helium.

[0080] The second heat storage circuit is used to drive the circulation of the second heat storage medium and recover waste heat from the aluminum plant's production, such as the waste heat from the flue gas generated in the roasting process 513 and the waste heat from the flue gas generated in the electrolytic aluminum production line 52. The second heat storage circuit is coordinated with the energy storage loop through a third heat exchanger 83, allowing the second heat storage medium to supply heat to the energy storage medium in the third heat exchanger 83 to supplement the thermal energy of the energy storage medium. Furthermore, the second heat storage circuit is coordinated with the energy release loop through a fourth heat exchanger 84, allowing the second heat storage medium to recover the waste heat from the energy release medium's power generation in the fourth heat exchanger 84. It is worth noting that in actual production, the highest temperature of the second heat storage medium is lower than that of the first heat storage medium; low-temperature heat storage media can be heat transfer oil, high-pressure feedwater, etc.

[0081] The aluminum plant energy management system has alternating energy storage and energy release modes. Specifically, the aluminum plant energy management system can switch between energy storage and energy release modes by switching the valves on and off between various circuits.

[0082] Specifically, in energy storage mode, the electrolytic aluminum production line 52 is connected to the mains power 71 for production; the energy storage circuit is directly connected to green electricity 72 for energy storage. Specifically, in energy storage mode, the energy storage circuit drives the energy storage medium to circulate and converts electrical energy into thermal energy of the energy storage medium; the first thermal storage circuit drives the first thermal storage medium to acquire thermal energy from the energy storage medium in the first heat exchanger 81 and store and / or supply the thermal energy to the aluminum plant for production; the second thermal storage circuit drives the second thermal storage medium to recover waste heat from the aluminum plant's production and supply heat to the energy storage medium in the third heat exchanger 83 to supplement the thermal energy of the energy storage medium. Simultaneously, the second thermal storage circuit can also preheat the air used in the aluminum plant's production.

[0083] In the energy release mode, the energy storage circuit disconnects from the green electricity 72 and ceases operation. The electrolytic aluminum production line 52 disconnects from the mains power 71 and connects to the electricity generated by the energy release circuit for production. Specifically, in the energy release mode, the first thermal storage circuit drives the first thermal storage medium to provide heat for the aluminum plant's production and heats the energy release medium in the second heat exchanger 82; the energy release circuit drives the energy release medium to convert thermal energy into electrical energy for the aluminum plant's production, and the waste heat generated during the energy release circuit's power generation can also be used for the aluminum plant's production; the second thermal storage circuit drives the second thermal storage medium to recover the aluminum plant's production waste heat and recovers the energy release medium's power generation waste heat in the fourth heat exchanger 84, and the second thermal storage circuit can also preheat the air used in the aluminum plant's production.

[0084] In the energy storage mode, the aforementioned aluminum plant energy management system converts electrical energy into heat energy through energy storage loops. The first heat storage loop acquires and stores the heat energy of the energy storage loop in the first heat exchanger 81 for use in aluminum plant production. The second heat storage loop recovers and stores the waste heat from aluminum plant production to supplement the heat energy of the energy storage loop in the third heat exchanger 83. In the energy release mode, the first heat storage loop not only supplies the stored heat energy to the aluminum plant for production but also supplies it to the energy release loop in the third heat exchanger 83. The energy release loop acquires the heat energy from the first heat storage loop and converts it into electrical energy for aluminum plant production. In addition to recovering and storing the waste heat from aluminum plant production, the second heat storage loop also recovers and stores the waste heat generated by the energy release loop in the fourth heat exchanger 84. This approach couples the energy storage and power generation system with the aluminum plant's production line, forming a comprehensive energy management system for the plant. On one hand, during periods of low grid electricity demand or when electricity prices are low, the system switches to energy storage mode; during periods of high grid electricity demand or when prices are high, it switches to energy release mode. This allows for rational planning of electricity consumption based on peak and off-peak electricity prices, saving on electricity costs. On the other hand, the system supplies heat to the aluminum plant through the first thermal storage loop and recovers waste heat from production through the second thermal storage loop, achieving cascaded utilization of thermal energy and reducing production energy consumption.

[0085] See Figure 1 The energy storage circuit includes a motor 11, a first compressor 12, a first expander 13, a first pipeline 14, and a second pipeline 15. The motor 11 is electrically connected to the green electricity 72. The first compressor 12 is electrically connected to the motor 11 and, driven by the motor 11, compresses the energy storage medium to convert electrical energy into thermal energy. The first expander 13 is coaxially arranged with the first compressor 12 and rotates under the drive of the energy storage medium. One end of the first pipeline 14 is connected to the medium outlet of the first compressor 12, and the other end of the first pipeline 14 connects to the medium inlet of the first expander 13 after passing through a first heat exchanger 81. The second pipeline 15 is connected to the medium outlet of the first expander 13, and the other end of the second pipeline 15 connects to the medium inlet of the first compressor 12 after passing through a third heat exchanger 83.

[0086] Optionally, in order to further make full use of the thermal energy of the energy storage medium, the energy storage loop also includes a fifth heat exchanger 85. The first pipeline 14 between the first heat exchanger 81 and the medium inlet of the first expander 13 is heat exchanged with the second pipeline 15 between the third heat exchanger 83 and the medium inlet of the first expander 13 through the fifth heat exchanger 85, so that the high-temperature energy storage medium between the first heat exchanger 81 and the medium inlet of the first expander 13 can exchange heat with the low-temperature energy storage medium between the third heat exchanger 83 and the medium inlet of the first expander 13.

[0087] Exemplary, in some embodiments, see Figure 2In energy storage mode, the energy storage loop operates. Green Electricity 72 is directly connected to Motor 11, which drives the first compressor 12 to rotate, compressing the energy storage medium and increasing its temperature and pressure. The temperature of the energy storage medium rises from 300°C to 550°C. The energy storage medium then enters the first heat exchanger 81 through the first pipeline 14, where it exchanges heat with the first heat storage medium in the first heat storage loop, thus heating the first heat storage medium. After heat exchange, the temperature of the energy storage medium drops to 400°C, and then it enters the fifth heat exchanger 85 to exchange heat with the low-temperature energy storage medium in the second pipeline 15, causing its temperature to drop to 300°C. Then the energy storage medium enters the first expander 13 and drives the first expander 13 to rotate. Since the first expander 13 and the first compressor 12 are coaxially connected by a coupling, some compression work can be saved. After the energy storage medium does work in the first expander 13, its temperature and pressure decrease, and the temperature drops to 100°C. After the energy storage medium comes out of the medium outlet of the first expander 13, it enters the third heat exchanger 83 along the second pipeline 15 to exchange heat with the second heat storage medium in the second heat storage circuit. After passing through the third heat exchanger 83, the temperature of the energy storage medium is heated from 100°C to 180°C. Then it continues to enter the fifth heat exchanger 85 along the second pipeline 15, and exchanges heat with the energy storage medium in the first pipeline 14 in the fifth heat exchanger 85, so that the temperature of the energy storage medium in the second pipeline 15 is heated from 180°C to 290°C. Finally, it returns to the first compressor 12, thus completing one cycle of the energy storage medium.

[0088] It is worth noting that the temperatures of the energy storage medium at each node described above are merely illustrative examples for ease of understanding and do not constitute an undue limitation on this application. In other implementations, the temperatures of the energy storage medium at each node can be specifically set according to actual production needs, which will not be elaborated here.

[0089] See Figure 1The first heat storage circuit includes a first storage tank 21, a second storage tank 22, a third pipeline 23, a fourth pipeline 24, and a fifth pipeline 25. Both the first and second storage tanks 21 and 22 are used to store the first heat storage medium, and the temperature of the first heat storage medium in the first storage tank 21 is lower than the temperature of the first heat storage medium in the second storage tank 22. One end of the third pipeline 23 is connected to the medium outlet of the first storage tank 21, and the other end of the third pipeline 23 is connected to the medium inlet of the second storage tank 22 after passing through a first heat exchanger 81. A first medium pump 231 is installed on the third pipeline 23 to drive the first heat storage medium to circulate within the third pipeline 23. One end of the fourth pipeline 24 is connected to the first medium outlet of the second storage tank 22, and the other end of the fourth pipeline 24 is connected to the first medium inlet of the first storage tank 21. A second medium pump 241 is installed on the fourth pipeline 24 to drive the first heat storage medium, and the fourth pipeline 24 is used to supply heat to the aluminum plant's production line. One end of the fifth pipeline 25 is connected to the second medium outlet of the second storage tank 22, and the other end of the fifth pipeline 25 is connected to the second medium inlet of the first storage tank 21 after passing through the second heat exchanger 82. A third medium pump 251 for driving the first heat storage medium is provided on the fifth pipeline 25.

[0090] Specifically, the fourth pipeline 24 is used to supply heat to the alumina production line 51 of the aluminum plant. Exemplarily, in some embodiments, the first heat storage return also includes a sixth heat exchanger 86, which is connected to the fourth pipeline 24. The sixth heat exchanger 86 is used to connect to the steam circulation system of the leaching process 511 of the aluminum plant to heat the condensate generated by the steam circulation system, so that the condensate is heated into steam for use by the leaching process 511.

[0091] Optionally, the first heat storage return may also include a seventh heat exchanger 87, which is connected to the fourth pipeline 24. The seventh heat exchanger 87 is used to connect to the air passage of the calcination process 513 of the aluminum plant to preheat the air required for the calcination process 513.

[0092] Furthermore, the sixth heat exchanger 86 and the seventh heat exchanger 87 are connected in parallel on the fourth pipeline 24 to ensure temperature matching. Understandably, in other embodiments, the fourth pipeline 24 may also be equipped with more heat exchangers so that the fourth pipeline 24 can also supply heat to other production lines in the aluminum plant.

[0093] For example, see Figure 2In energy storage mode, the first thermal storage loop opens the third pipeline 23 and the fourth pipeline 24, and closes the fifth pipeline 25. The first thermal storage medium in the first storage tank 21 is transported by the first medium pump 231 along the third pipeline 23 to the first heat exchanger 81 to exchange heat with the energy storage medium in the energy storage loop, causing the temperature of the first thermal storage medium to rise from 300℃ to 500℃. Then, the first thermal storage medium continues to be transported along the third pipeline 23 to the second storage tank 22 for storage. The second medium pump 241 extracts the first thermal storage medium from the second storage tank 22 and transports it along the fourth pipeline 24 to the aluminum plant's production line. The first thermal storage medium in the fourth pipeline 24 is divided into two paths. One path is transported to the sixth heat exchanger 86 to heat the condensate generated by the steam circulation system, heating the condensate into 260℃ steam for use in the leaching process 511. After the steam heat energy is released, it turns back into condensate and returns to the sixth heat exchanger 86. After passing through the sixth heat exchanger 86, the temperature of the first thermal storage medium decreases from 500℃ to 300℃ and returns to the first storage tank 21 from the first medium inlet. Another path of the first thermal storage medium in the fourth pipeline 24 enters the seventh heat exchanger 87 to preheat the air to 300℃. After preheating, the air enters the combustion chamber and mixes with the fuel gas for combustion, producing 1200℃ flue gas that enters the calcination section to release heat. This path of the first thermal storage medium also decreases from 500℃ to 300℃ after passing through the seventh heat exchanger 87 and returns to the first storage tank 21 from the first medium inlet, thus completing the circulation of the first thermal storage medium in the energy storage mode.

[0094] See Figure 3 In the energy release mode, the first thermal storage circuit opens the fourth pipe 24 and the fifth pipe 25. A portion of the second thermal storage medium in the second storage tank 22 enters the fourth pipe 24 through the second medium pump 241. The circulation of the first thermal storage medium in the fourth pipe 24 is the same as in the energy storage mode, and will not be described in detail here. The other portion of the second thermal storage medium in the second storage tank 22 is sent to the fifth pipe 25 through the third medium pump 251, and enters the second heat exchanger 82 along the fifth pipe 25 to exchange heat with the energy release working medium in the energy release circuit to heat the energy release working medium. After passing through the second heat exchanger 82, the temperature of the second thermal storage medium decreases from 500℃ to 300℃, and returns to the first storage tank 21 from the second medium inlet, thus completing the circulation of the first thermal storage medium in the energy release mode.

[0095] See Figure 1In some embodiments, the second heat storage circuit includes a third storage tank 31, a fourth storage tank 32, a sixth pipeline 33, a seventh pipeline 34, and an eighth pipeline 35, wherein the third storage tank 31 and the fourth storage tank 32 are both used to store the second heat storage medium, and the temperature of the second heat storage medium in the third storage tank 31 is lower than the temperature of the second medium in the fourth storage tank 32. One end of the sixth pipeline 33 is connected to the medium outlet of the third storage tank 31, and the other end of the sixth pipeline 33 is connected to the medium inlet of the fourth storage tank 32 after passing through the fourth heat exchanger 84; one end of the seventh pipeline 34 is connected to the medium outlet of the third storage tank 31, and the other end of the seventh pipeline 34 is connected to the medium inlet of the fourth storage tank 32. The seventh pipeline 34 is used to recover waste heat from the aluminum plant; one end of the eighth pipeline 35 is connected to the medium outlet of the fourth storage tank 32, and the other end of the eighth pipeline 35 is connected to the medium inlet of the third storage tank 31 after passing through the third heat exchanger 83; wherein, the medium outlet of the third storage tank 31 is connected to the fourth medium pump 341; and the medium outlet of the fourth storage tank 32 is connected to the fifth medium pump 351.

[0096] For example, the seventh pipeline 34 is used to recover the waste heat of the flue gas from the calcination process 513 of the aluminum plant. Specifically, the second heat storage circuit also includes an eighth heat exchanger 88, which is connected to the seventh pipeline 34. The eighth heat exchanger 88 is used to connect to the flue gas pipeline of the calcination process 513 of the aluminum plant to recover the waste heat of the flue gas from the calcination process 513.

[0097] Furthermore, the seventh pipeline 34 is used to recover the waste heat from the flue gas of the calcination process 513 in the aluminum plant. Specifically, the second heat storage circuit also includes a ninth heat exchanger 89, which is connected to the seventh pipeline 34. The ninth heat exchanger 89 is used to connect to the flue gas pipeline of the electrolytic aluminum production line 52 in the aluminum plant to recover the waste heat from the flue gas of the electrolytic aluminum production line 52.

[0098] Furthermore, the eighth heat exchanger 88 and the ninth heat exchanger 89 are connected in parallel on the seventh pipe 34 to ensure temperature matching. Understandably, in other embodiments, the seventh pipe 34 may also be equipped with more heat exchangers so that the seventh pipe 34 can also recover waste heat from other production lines in the aluminum plant.

[0099] Exemplarily, in some embodiments, the eighth pipeline 35, in addition to supplying heat to the energy storage medium in the energy storage loop through the third heat exchanger 83, can also supply heat to the aluminum plant production line. Specifically, in some embodiments, the second heat storage loop further includes a tenth heat exchanger 810, which is connected to the eighth pipeline 35 and arranged in parallel with the third heat exchanger 83. The tenth heat exchanger 810 is used to connect to the air passage of the calcination process 513 in the aluminum plant to preheat the air required for the calcination process 513. Further, the tenth heat exchanger 810 is arranged in series with the seventh heat exchanger 87, that is, the air required for the calcination process 513 is first preheated by the tenth heat exchanger 810 and then preheated by the seventh heat exchanger 87 to ensure that the air required for the calcination process 513 is preheated to the required temperature.

[0100] For example, see Figure 2 In energy storage mode, the second thermal storage circuit disconnects the sixth pipeline 33 and opens the seventh pipeline 34 and the eighth pipeline 35. The second thermal storage medium in the third storage tank 31 enters the seventh pipeline 34 after passing through the fourth medium pump 341. The second thermal storage medium in the seventh pipeline 34 is divided into two paths. One path of the second thermal storage medium is transported to the eighth heat exchanger 88 to recover the waste heat from the flue gas of the roasting process 513, and the temperature of the second thermal storage medium rises from 120°C to 200°C. The other path of the second thermal storage medium is transported to the ninth heat exchanger 89 to recover the waste heat from the flue gas of the electrolytic aluminum production line 52, and the temperature of this path of the second thermal storage medium also rises from 120°C to 200°C. Finally, the two paths of the second thermal storage medium are combined and enter the fourth storage tank 32. The second thermal storage medium in the fourth storage tank 32 enters the eighth pipeline 35 after passing through the fifth medium pump 351. Within the eighth pipeline 35, the second thermal storage medium is divided into two streams. One stream is sent to the third heat exchanger 83 to heat the energy storage medium in the energy storage loop, causing its temperature to drop from 200°C to 120°C. The other stream is sent to the tenth heat exchanger 810 to preheat the air required for the calcination process 513, also causing its temperature to drop from 200°C to 120°C. Finally, the two streams of second thermal storage medium are combined and returned to the third storage tank 31, completing one cycle of the second thermal storage medium in energy storage mode.

[0101] In the energy release mode, the sixth pipe 33 of the second thermal storage circuit is opened, while the seventh pipe 34 remains open. Simultaneously, the pipe in the eighth pipe 35 that passes through the third heat exchanger 83 is closed, while the pipe that passes through the tenth heat exchanger 810 remains open. Specifically, the second thermal storage medium in the third storage tank 31 is divided into two paths after passing through the fourth medium pump 341. One path enters the sixth pipe 33, and the other enters the seventh pipe 34. The circulation of the second thermal storage medium entering the seventh pipe 34 is the same as in the energy storage mode and will not be elaborated here. The second thermal storage medium in the sixth pipe 33 enters the fourth heat exchanger 84 to recover the waste heat from the energy release medium's power generation. The temperature of the second thermal storage medium then rises from 120°C to 200°C and enters the fourth storage tank 32. The second heating medium in the fourth storage tank 32 enters the tenth heat exchanger 810 after passing through the fifth medium pump 351 to preheat the air required for the calcination process 513. Then, the second heat storage medium is reduced from 200°C to 120°C and returned to the third storage tank 31, thus completing one cycle of the second heat storage medium in the energy storage mode.

[0102] Optionally, in some embodiments, the energy release circuit includes a second expander 41, a second compressor 42, a generator 45, a ninth pipeline 43, and a tenth pipeline 44. The second expander 41 rotates under the drive of the energy-releasing working medium to convert the thermal energy of the working medium into mechanical energy. The second compressor 42 is coaxially arranged with the second expander 41 and rotates under the drive of the second expander 41 to compress the energy-releasing working medium. The generator 45 is connected to the second compressor 42 and rotates under the drive of the second compressor 42 to convert mechanical energy into electrical energy for use in the aluminum plant production line. Specifically, the generator 45 supplies power to the electrolytic aluminum production line 52 of the aluminum plant. A second converter 62 is provided between the generator 45 and the electrolytic aluminum production line 52. The second converter 62 is used to convert the alternating current generated by the generator 45 into direct current for use in electrolytic aluminum production. One end of the ninth pipe 43 is connected to the medium outlet of the second compressor 42, and the other end of the ninth pipe 43 is connected to the medium inlet of the second expander 41 after passing through the second heat exchanger 82. One end of the tenth pipe 44 is connected to the medium outlet of the second expander 41, and the other end of the tenth pipe 44 is connected to the medium inlet of the second compressor 42 after passing through the fourth heat exchanger 84.

[0103] Furthermore, in some embodiments, after the energy-releasing medium performs work on the second expander 41 to drive the second expander 41 to rotate, it still maintains a high temperature. In order to make full use of the waste heat after the energy-releasing medium generates electricity, in some embodiments, the energy-releasing circuit also includes an eleventh heat exchanger 811. The eleventh heat exchanger 811 is connected to the tenth pipeline 44 and is connected in series with the fourth heat exchanger 84. The eleventh heat exchanger 811 is located upstream of the fourth heat exchanger. The eleventh heat exchanger 811 is used to connect with the steam circulation system of the aluminum plant's leaching process 511 to heat the condensate generated by the steam circulation system.

[0104] Specifically, in energy storage mode, the energy release circuit is not operational. In energy release mode, the energy release medium enters the second expander 41 and performs work on it, driving the second expander 41 to rotate. The second compressor 42 rotates synchronously under the drive of the second expander 41, driving the generator 45 to rotate. The generator 45 generates electricity to supply power to the electrolytic aluminum production line 52. The temperature of the energy release medium decreases from 450°C to 300°C after passing through the second expander 41. After exiting the second expander 41, the energy release medium enters the eleventh heat exchanger 811 along the tenth pipeline 44 to heat the condensate generated by the steam circulation system, reducing the temperature of the energy release medium from 300°C to 220°C. Subsequently, the energy release medium passes through the fourth heat exchanger 84 to heat the second heat storage medium, reducing the temperature of the energy release medium from 220°C to 150°C before entering the second compressor 42. The second compressor 42 compresses the energy release medium, increasing its temperature from 150°C to 250°C. After exiting the second compressor 42, the energy-releasing working medium enters the second heat exchanger 82 along the ninth pipeline 43 to exchange heat with the first heat storage medium. The energy-releasing working medium is heated from 150°C to 450°C and then enters the second expander 41 again, thus completing one cycle of the energy-releasing working medium.

[0105] An embodiment of this application also provides an energy control method for an aluminum plant using the energy management system of any of the above embodiments. The energy control method for the aluminum plant includes an energy storage mode and an energy release mode.

[0106] See Figure 2 Specifically, in some embodiments, the energy control method for aluminum plants in energy storage mode includes the following steps:

[0107] S110: The aluminum plant's electrolytic aluminum production line 52 is connected to the mains power 71, and the energy storage circuit is directly connected to green electricity 72;

[0108] S120: The energy storage circuit drives the energy storage medium to circulate and converts the electrical energy of Green Electricity 72 into the thermal energy of the energy storage medium;

[0109] Specifically, the electric motor 11 drives the first compressor 12 to rotate, compressing the energy storage medium and increasing its temperature and pressure. The temperature of the energy storage medium rises from 300°C to 550°C. The energy storage medium then enters the first heat exchanger 81 through the first pipeline 14, where it exchanges heat with the first heat storage medium in the first heat storage circuit to heat the first heat storage medium. After heat exchange, the temperature of the energy storage medium drops to 400°C, and then it enters the fifth heat exchanger 85 to exchange heat with the low-temperature energy storage medium in the second pipeline 15, where its temperature drops to 300°C. Then the energy storage medium enters the first expander 13 and drives the first expander 13 to rotate. Since the first expander 13 and the first compressor 12 are coaxially connected by a coupling, some compression work can be saved. After the energy storage medium does work in the first expander 13, its temperature and pressure decrease, and the temperature decreases to 100°C. After the energy storage medium comes out of the medium outlet of the first expander 13, it enters the third heat exchanger 83 along the second pipeline 15 to exchange heat with the second heat storage medium in the second heat storage circuit. After passing through the third heat exchanger 83, the temperature of the energy storage medium is heated from 100°C to 180°C. Then it continues to enter the fifth heat exchanger 85 along the second pipeline 15, and exchanges heat with the energy storage medium in the first pipeline 14 in the fifth heat exchanger 85, so that the temperature of the energy storage medium in the second pipeline 15 is heated from 180°C to 290°C. Finally, it returns to the first compressor 12.

[0110] S130: The first thermal storage circuit drives the first thermal storage medium to circulate, so that the first thermal storage medium can obtain the thermal energy of the energy storage medium in the first heat exchanger 81, and store and / or supply the thermal energy to the aluminum plant for production.

[0111] Specifically, the first thermal storage circuit opens the third pipeline 23 and the fourth pipeline 24, and closes the fifth pipeline 25. The first thermal storage medium in the first storage tank 21 is transported by the first medium pump 231 along the third pipeline 23 to the first heat exchanger 81 to exchange heat with the energy storage medium in the energy storage circuit, causing the temperature of the first thermal storage medium to rise from 300℃ to 500℃. Then, the first thermal storage medium continues to be transported along the third pipeline 23 to the second storage tank 22 for storage. The second medium pump 241 extracts the first thermal storage medium from the second storage tank 22 and transports it along the fourth pipeline 24 to the aluminum plant's production line. The first thermal storage medium in the fourth pipeline 24 is divided into two paths. One path is transported to the sixth heat exchanger 86 to heat the condensate generated by the steam circulation system, heating the condensate into 260℃ steam for use in the leaching process 511. After the steam heat energy is released, it turns back into condensate and returns to the sixth heat exchanger 86. The first heat storage medium, after passing through the sixth heat exchanger 86, has its temperature reduced from 500℃ to 300℃ and returns to the first storage tank 21. Another path of the first heat storage medium in the fourth pipeline 24 enters the seventh heat exchanger 87 to preheat the air to 300℃. After preheating, the air enters the combustion chamber and mixes with the fuel gas for combustion, producing 1200℃ flue gas that releases heat in the calcination section. This path of the first heat storage medium, after passing through the seventh heat exchanger 87, also has its temperature reduced from 500℃ to 300℃ and returns to the first storage tank 21.

[0112] S140: The second thermal storage circuit drives the second thermal storage medium to circulate, so that the second thermal storage medium recovers the waste heat from the aluminum plant's production and supplies heat to the energy storage medium in the third heat exchanger 83, while preheating the air used in the aluminum plant's production.

[0113] Specifically, the second thermal storage circuit disconnects the sixth pipeline 33 and opens the seventh pipeline 34 and the eighth pipeline 35. The second thermal storage medium in the third storage tank 31 enters the seventh pipeline 34 after passing through the fourth medium pump 341. The second thermal storage medium in the seventh pipeline 34 is divided into two paths. One path of the second thermal storage medium is transported to the eighth heat exchanger 88 to recover the waste heat from the flue gas of the roasting process 513, and the temperature of the second thermal storage medium rises from 120°C to 200°C. The other path of the second thermal storage medium is transported to the ninth heat exchanger 89 to recover the waste heat from the flue gas of the electrolytic aluminum production line 52, and the temperature of this path of the second thermal storage medium also rises from 120°C to 200°C. Finally, the two paths of the second thermal storage medium are combined and enter the fourth storage tank 32. The second thermal storage medium in the fourth storage tank 32 enters the eighth pipeline 35 after passing through the fifth medium pump 351. The second thermal storage medium in the eighth pipeline is divided into two streams. One stream is sent to the third heat exchanger 83 to heat the energy storage medium in the energy storage loop, reducing its temperature from 200°C to 120°C. The other stream is sent to the tenth heat exchanger 810 to preheat the air required for the calcination process 513, also reducing its temperature from 200°C to 120°C. Finally, the two streams of second thermal storage medium are combined and returned to the third storage tank 31.

[0114] See Figure 3 In some embodiments, the energy control method for aluminum plants includes the following steps in the energy release mode:

[0115] S210: The aluminum plant's electrolytic aluminum production line 52 disconnects from the mains power 71 and connects to the energy release circuit, while the energy storage circuit disconnects from the green power 72.

[0116] S220: The first thermal storage circuit drives the first thermal storage medium to circulate, so as to provide heat for the aluminum plant's production and to provide heat to the energy-releasing working medium in the second heat exchanger 82.

[0117] Specifically, the first thermal storage circuit disconnects the third pipeline 23 and opens the fourth pipeline 24 and the fifth pipeline 25. A portion of the second thermal storage medium in the second storage tank 22 enters the fourth pipeline 24 through the second medium pump 241. The circulation of the first thermal storage medium in the fourth pipeline 24 is the same as in the energy storage mode, which will not be described in detail here. The other portion of the second thermal storage medium in the second storage tank 22 is sent to the fifth pipeline 25 through the third medium pump 251, and enters the second heat exchanger 82 along the fifth pipeline 25 to exchange heat with the energy release working medium in the energy release circuit to heat the energy release working medium. After passing through the second heat exchanger 82, the temperature of the second thermal storage medium decreases from 500°C to 300°C, and returns to the first storage tank 21 from the second medium inlet of the first storage tank 21.

[0118] S230: The energy release circuit drives the energy release working medium to circulate, so as to convert the thermal energy of the energy release working medium into electrical energy and use it for the electrolytic aluminum production line 52, while generating waste heat for the aluminum plant's production.

[0119] Specifically, after the energized working fluid enters the second expander 41, it performs work on the second expander 41 to drive its rotation. The second compressor 42, driven by the second expander 41, rotates synchronously and drives the generator 45 to rotate. The generator 45 generates electricity to supply power to the electrolytic aluminum production line 52. The temperature of the energized working fluid decreases from 450°C to 300°C after passing through the second expander 41. After exiting the second expander 41, the energized working fluid enters the eleventh heat exchanger 811 along the tenth pipeline 44 to heat the condensate produced by the steam circulation system. The temperature of the energized working fluid decreases from 300°C to 220°C. Subsequently, the energized working fluid passes through the fourth heat exchanger 84 to heat the second heat storage medium, decreasing its temperature from 220°C to 150°C before entering the second compressor 42. The second compressor 42 compresses the energized working fluid, raising its temperature from 150°C to 250°C. After exiting the second compressor 42, the energy-releasing working medium enters the second heat exchanger 82 along the ninth pipeline 43 to exchange heat with the first heat storage medium. The energy-releasing working medium is heated from 150°C to 450°C and then enters the second expander 41 again.

[0120] S240: The second thermal storage circuit drives the second thermal storage medium to circulate, so that the second thermal storage medium recovers the waste heat from the aluminum plant's production and recovers the waste heat from power generation of the energy-releasing working medium in the fourth heat exchanger 84, while preheating the air used in the aluminum plant's production.

[0121] Specifically, the sixth pipe 33 of the second thermal storage circuit is opened, while the seventh pipe 34 remains open. The pipe in the eighth pipe 35 that passes through the third heat exchanger 83 is closed, while the pipe that passes through the tenth heat exchanger 810 remains open. Specifically, the second thermal storage medium in the third storage tank 31 is divided into two paths after passing through the fourth medium pump 341. One path enters the sixth pipe 33, and the other path enters the seventh pipe 34. The circulation of the second thermal storage medium entering the seventh pipe 34 is the same as in the energy storage mode, and will not be described in detail here. The second thermal storage medium in the sixth pipe 33 enters the fourth heat exchanger 84 to recover the waste heat after the energy release medium generates electricity. The temperature of the second thermal storage medium then rises from 120°C to 200°C and enters the fourth storage tank 32. The second heating medium in the fourth storage tank 32 enters the tenth heat exchanger 810 after passing through the fifth medium pump 351 to preheat the air required for the roasting process 513. Then, the second heat storage medium is reduced from 200°C to 120°C and returned to the third storage tank 31.

[0122] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0123] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. An energy management system for an aluminum plant, characterized in that, include: An energy storage circuit is used to drive the energy storage medium to circulate and can convert electrical energy into thermal energy of the energy storage medium. The first thermal storage circuit is used to drive the circulation of the first thermal storage medium and supply heat to the aluminum plant for production. The first thermal storage circuit is in heat exchange cooperation with the energy storage circuit through the first heat exchanger. An energy release circuit is used to drive the energy release working medium to circulate and convert the thermal energy of the energy release working medium into electrical energy for use in aluminum plant production. The energy release circuit is in heat exchange cooperation with the first heat storage circuit through a second heat exchanger. The second thermal storage circuit is used to drive the second thermal storage medium to circulate and recover the waste heat from the aluminum plant. The second thermal storage circuit is in heat exchange cooperation with the energy storage circuit through a third heat exchanger, and the second thermal storage circuit is in heat exchange cooperation with the energy release circuit through a fourth heat exchanger. The energy management system of the aluminum plant has alternating energy storage and energy release modes: In the energy storage mode, the energy storage circuit drives the energy storage medium to circulate and converts electrical energy into thermal energy of the energy storage medium; the first thermal storage circuit drives the first thermal storage medium to acquire the thermal energy of the energy storage medium in the first heat exchanger and stores and / or supplies the thermal energy to the aluminum plant for production; the second thermal storage circuit drives the second thermal storage medium to recover the waste heat from the aluminum plant's production and supply heat to the energy storage medium in the third heat exchanger, while preheating the air used in the aluminum plant's production. In the energy release mode, the first thermal storage circuit drives the first thermal storage medium to provide heat for the aluminum plant's production and to provide heat to the energy release medium in the second heat exchanger; the energy release circuit drives the energy release medium to convert thermal energy into electrical energy for the aluminum plant's production and to generate waste heat for the aluminum plant's production; the second thermal storage circuit drives the second thermal storage medium to recover the aluminum plant's production waste heat and to recover the energy release medium's power generation waste heat in the fourth heat exchanger, while preheating the air used in the aluminum plant's production.

2. The energy management system for aluminum plants according to claim 1, characterized in that, The energy storage circuit includes: An electric motor, used for electrical connection to green electricity; A first compressor is electrically connected to the electric motor, and the first compressor is capable of compressing the energy storage medium under the drive of the electric motor; A first expander is coaxially arranged with the first compressor, and the first expander can rotate under the drive of the energy storage working fluid; The first pipeline has one end connected to the medium outlet of the first compressor, and the other end connected to the medium inlet of the first expander after passing through the first heat exchanger. The second pipeline is connected to the medium outlet of the first expander, and the other end of the second pipeline is connected to the medium inlet of the first compressor after passing through the third heat exchanger.

3. The energy management system for aluminum plants according to claim 2, characterized in that, The energy storage loop also includes a fifth heat exchanger, and the first pipeline between the first heat exchanger and the medium inlet of the first expander is heat exchanged with the second pipeline between the fifth heat exchanger and the medium inlet of the first expander.

4. The energy management system for aluminum plants according to claim 1, characterized in that, The first heat storage recovery includes: The first storage tank is used to store the first heat storage medium; The second storage tank is used to store the first heat storage medium, and the temperature of the first heat storage medium in the first storage tank is lower than the temperature of the first heat storage medium in the second storage tank. A third pipeline, one end of which is connected to the medium outlet of the first storage tank, and the other end of which is connected to the medium inlet of the second storage tank after passing through the first heat exchanger, and a first medium pump is provided on the third pipeline; The fourth pipeline has one end connected to the first medium outlet of the second storage tank and the other end connected to the first medium inlet of the first storage tank. A second medium pump is installed on the fourth pipeline, which is used to supply heat to the production line of the aluminum plant. The fifth pipeline has one end connected to the second medium outlet of the second storage tank, and the other end connected to the second medium inlet of the first storage tank after passing through the second heat exchanger. A third medium pump is provided on the fifth pipeline.

5. The energy management system for aluminum plants according to claim 4, characterized in that, The first heat storage recovery also includes: A sixth heat exchanger, connected to the fourth pipeline, is used to connect to the steam circulation system of the aluminum plant's leaching process to heat the condensate generated by the steam circulation system; and / or, The seventh heat exchanger is connected to the fourth pipeline and is used to connect to the air channel of the calcination process of the aluminum plant to preheat the air required for the calcination process.

6. The energy management system for aluminum plants according to claim 1, characterized in that, The second thermal storage circuit includes: The third storage tank is used to store the second heat medium; The fourth storage tank is used to store the second heat storage medium, and the temperature of the second heat storage medium in the third storage tank is lower than the temperature of the second medium in the fourth storage tank. The sixth pipeline has one end connected to the medium outlet of the third storage tank, and the other end connected to the medium inlet of the fourth storage tank after passing through the fourth heat exchanger. The seventh pipeline has one end connected to the medium outlet of the third storage tank and the other end connected to the medium inlet of the fourth storage tank. The seventh pipeline is used to recover waste heat from the aluminum plant's production. The eighth pipeline has one end connected to the medium outlet of the fourth storage tank, and the other end connected to the medium inlet of the third storage tank after passing through the third heat exchanger. The third storage tank is connected to a fourth medium pump at its medium outlet; the fourth storage tank is connected to a fifth medium pump at its medium outlet.

7. The energy management system for aluminum plants according to claim 6, characterized in that, The second thermal storage circuit also includes: An eighth heat exchanger, connected to the seventh pipeline, is used to connect to the flue gas pipeline of the aluminum plant's roasting process to recover waste heat from the flue gas of the roasting process; and / or, A ninth heat exchanger, connected to the seventh pipeline, is used to connect to the flue gas pipeline of the aluminum plant's electrolytic aluminum production line to recover waste heat from the flue gas of the electrolytic aluminum production line; and / or, The tenth heat exchanger is connected to the eighth pipeline and is arranged in parallel with the third heat exchanger. The tenth heat exchanger is used to connect to the air channel of the calcination process of the aluminum plant to preheat the air required for the calcination process.

8. The energy management system for aluminum plants according to claim 1, characterized in that, The energy release circuit includes: The second expander is capable of rotating under the drive of the energy-releasing working medium to convert the thermal energy of the energy-releasing working medium into mechanical energy; The second compressor is coaxially arranged with the second expander, and the second compressor can rotate and compress the energy-releasing working fluid under the drive of the second expander; A generator connected to the second compressor, the generator being able to rotate under the drive of the second compressor to convert mechanical energy into electrical energy and supply it to the aluminum plant production line; The ninth pipeline has one end connected to the medium outlet of the second compressor, and the other end connected to the medium inlet of the second expander after passing through the second heat exchanger. The tenth pipeline has one end connected to the medium outlet of the second expander and the other end connected to the medium inlet of the second compressor after passing through the fourth heat exchanger.

9. The energy management system for aluminum plants according to claim 8, characterized in that, The energy release circuit also includes an eleventh heat exchanger, which is connected to the tenth pipeline and connected in series with the fourth heat exchanger. The eleventh heat exchanger is located upstream of the fourth heat exchanger and is used to connect with the steam circulation system of the aluminum plant's leaching process to heat the condensate generated by the steam circulation system.

10. An energy control method for an aluminum plant, implemented using the energy management system for an aluminum plant as described in any one of claims 1-9, characterized in that, The energy control method for the aluminum plant includes an energy storage mode and an energy release mode; The energy storage mode includes the following steps: The aluminum plant's electrolytic aluminum production line is connected to the mains power, and the energy storage circuit uses green electricity for direct connection; The energy storage circuit drives the energy storage medium to circulate and converts the electrical energy of the green electricity into the thermal energy of the energy storage medium; The first thermal storage circuit drives the first thermal storage medium to circulate, so that the first thermal storage medium can acquire the thermal energy of the energy storage medium in the first heat exchanger, and store and / or supply the thermal energy to the aluminum plant for production. The second thermal storage circuit drives the second thermal storage medium to circulate, so that the second thermal storage medium recovers the waste heat from the aluminum plant's production and supplies heat to the energy storage medium in the third heat exchanger, while preheating the air used in the aluminum plant's production. The energy release mode includes the following steps: The aluminum plant's electrolytic aluminum production line is disconnected from the mains power and electrically connected to the energy release circuit, while the energy storage circuit is disconnected from the green electricity. The first thermal storage circuit drives the first thermal storage medium to circulate, so as to provide heat for the aluminum plant's production and to provide heat to the energy-releasing working medium in the second heat exchanger; The energy release circuit drives the energy release working medium to circulate, so as to convert the thermal energy of the energy release working medium into electrical energy and supply it to the electrolytic aluminum production line, while generating waste heat for the aluminum plant to use in production. The second thermal storage circuit drives the second thermal storage medium to circulate, so that the second thermal storage medium recovers the waste heat from the aluminum plant's production and recovers the waste heat from the power generation of the energy-releasing working medium in the fourth heat exchanger, while preheating the air used in the aluminum plant's production.

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