Energy storage system for aluminum electrolytic cells

Abstract

An energy storage system for aluminum electrolytic cells, relating to the technical field of aluminum electrolysis, and comprising electrolytic cell heat absorption devices. The electrolytic cell heat absorption devices are arranged on aluminum electrolytic cells; the electrolytic cell heat absorption devices are connected to a waste heat exchanger by means of connecting pipelines, the waste heat exchanger is connected to a waste heat power generation device; the waste heat power generation device generates power by using the waste heat of the waste heat exchanger; a battery energy storage device is further connected to an external power supply system; and a direct-current bus connection device is further connected to the aluminum electrolytic cells. In the present invention, the electrolytic cell heat absorption devices are installed on the aluminum electrolytic cells to collect waste heat of the electrolytic cells; power is generated by the waste heat power generation device and stored in the battery energy storage device, and the battery energy storage device can also be charged by the external power supply system such as grid power; and under set conditions, the battery energy storage device supplies power to the electrolytic cells, achieving the objective of saving electric charge by means of peak shaving and valley filling.

Description

An aluminum electrolytic cell energy storage system Technical Field

[0001] This invention belongs to the field of aluminum electrolysis technology, and particularly relates to an energy storage system for aluminum electrolysis cells. Background Technology

[0002] my country's new energy power generation technology is booming, with the number of installed capacity of new energy units such as wind power, solar power, and hydropower gradually increasing. However, due to the randomness and volatility of some types of new energy power generation, in order to encourage users to use more new energy electricity, the government has introduced a peak-valley electricity pricing policy. Electricity prices are reduced during off-peak hours and increased during peak hours, with the average daily electricity price remaining basically unchanged.

[0003] Electrolytic aluminum is a typical energy-intensive industry. Electrolytic aluminum enterprises are characterized by high electricity consumption, high load factor, and stable load, with electricity costs accounting for about 40% of total costs. Faced with the vigorous development of new energy power generation and increasingly stringent energy conservation and emission reduction standards, electrolytic aluminum enterprises can leverage their own characteristics to organically combine peak-valley electricity pricing mechanisms with electrolytic aluminum production. This allows them to utilize lower-cost new energy power through peak shaving and valley filling, thereby reducing electricity costs.

[0004] Typically, a single electrolysis series has around 300 electrolytic cells. During aluminum electrolysis, the theoretical energy utilization rate is only about 50%, with the majority of the remaining energy lost to the environment as heat. By collecting this lost heat through heat absorption devices and returning this energy to the electrolytic cells, the power consumption of the electrolytic cells can be reduced. Summary of the Invention

[0005] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides an aluminum electrolytic cell energy storage system. By installing an electrolytic cell heat absorption device on the aluminum electrolytic cell, the waste heat of the electrolytic cell is collected, and the waste heat power generation device generates electricity, which is stored in a battery energy storage device. The battery energy storage device can be charged by an external power supply system such as the grid. Under set conditions, the battery energy storage device supplies power to the electrolytic cell to save electricity costs by peak shaving and valley filling.

[0006] To achieve the above objectives, the main technical solutions adopted by the present invention include:

[0007] An aluminum electrolytic cell energy storage system includes an electrolytic cell heat absorption device, which is installed on the aluminum electrolytic cell. The heat exchange medium flows through the heat exchange pipes in the electrolytic cell heat absorption device to exchange heat with the aluminum electrolytic cell. The electrolytic cell heat absorption device is connected to a waste heat exchanger via connecting pipes. The waste heat exchanger is connected to a waste heat power generation device, which generates electricity using the waste heat from the waste heat exchanger. The generated electricity is supplied to a battery energy storage device and the plant's power grid. The battery energy storage device is connected to a DC bus access device and also to an external power supply system. The battery energy storage device is charged simultaneously or separately by the waste heat power generation device and the external power supply system. The DC bus access device is also connected to the aluminum electrolytic cell.

[0008] Furthermore, the battery energy storage device provides load to the outside world when the power grid is cut off and the electrolytic series cannot obtain sufficient power load, during peak periods when the power grid price is high, or when there is excess power in the battery energy storage device. The battery energy storage device is also charged by the external power supply system when the low-priced new energy power supply network is used as the external power supply system, and when the power grid is used as the external power supply system during off-peak hours.

[0009] Furthermore, a power circulation device is provided on the connecting pipeline between the electrolytic cell heat absorption device and the waste heat exchanger.

[0010] Furthermore, the waste heat exchanger is connected to the electrolytic cell heat absorption device of several aluminum electrolytic cells via connecting pipelines, and the waste heat power generation device is connected to several waste heat exchangers.

[0011] Furthermore, the electrolytic cell heat absorption device consists of several heat absorbers connected in series or in parallel, distributed at several locations in the aluminum electrolytic cell, including those closely attached to the side of the cell shell, closely attached to the steel rod, closely attached to the surface of the covering material, and placed inside the side carbon block.

[0012] Furthermore, the aluminum electrolysis cell is divided into several regions along its length by cradle frames. The regions between two adjacent cradle frames are the same region. The absorbers between different regions are installed in parallel, while the absorbers within the same region are installed in series.

[0013] Furthermore, each waste heat power generation unit is equipped with one or more battery energy storage devices, which include: input AC power with a voltage consistent with the outlet voltage of the waste heat power generation unit; and output DC power with a voltage consistent with the DC bus voltage of the electrolysis power supply.

[0014] Furthermore, the battery energy storage device is equipped with a control and protection device that communicates with the rectifier current stabilization control system; the control and protection device includes: sending the supplied current value parameters to the rectifier current stabilization control system; receiving voltage regulation commands sent by the rectifier current stabilization control system; and receiving emergency shutdown commands sent by the rectifier current stabilization control system to stop supplying power to the DC bus.

[0015] Furthermore, the battery energy storage device receives electrical energy from the waste heat power generation device and stores electrical energy at off-peak electricity prices; the amount of electrical energy stored by the battery energy storage device at off-peak electricity prices is determined based on the AC backup power supply of the electrolysis area and is used as backup power reserve for that area.

[0016] Furthermore, an electrolysis series shares a single DC bus access device. The battery energy storage device is connected to the DC bus access device, which is connected to the electrolysis power supply DC main bus via an aluminum bus connection to supply power to the electrolytic cells. At the connection point between the DC main bus and the electrolysis power supply DC main bus, a bus access protection cabinet is installed. The bus access protection cabinet includes: preventing current backflow; and installing an isolation blade to enable power disconnection during maintenance.

[0017] The beneficial effects of this invention are as follows: The aluminum electrolysis cell energy storage system of this invention collects waste heat from the electrolysis cell by installing a heat absorption device on the aluminum electrolysis cell, generates electricity through a waste heat power generation device, and then stores the electricity in a battery energy storage device. The battery energy storage device can be charged by an external power supply system such as the grid. At specific times, the battery energy storage device supplies power to the electrolysis cell, thereby saving electricity costs by peak shaving and valley filling, and reducing the electricity costs of aluminum electrolysis enterprises. Attached Figure Description

[0018] Figure 1 is a schematic diagram of the aluminum electrolysis cell energy storage system of the present invention;

[0019] Figure 2 is a schematic diagram of the heat absorber in the aluminum electrolysis cell energy storage system of the present invention;

[0020] Figure 3 is a schematic diagram of the heat absorption device of the electrolytic cell closely attached to the side of the cell shell;

[0021] Figure 4 is a schematic diagram of the electrolytic cell heat absorption device installed inside the side carbon block.

[0022] In the diagram: 1. Aluminum electrolytic cell; 2. Electrolytic cell heat absorption device; 3. Cold pipe connecting the pipeline; 4. Power circulation device; 5. Heat pipe connecting the pipeline; 6. Waste heat exchanger; 7. Plant power grid; 8. Waste heat power generation device; 9. Battery energy storage device; 10. DC bus access device; 11. External power supply system; 12. Heat absorption pipeline inside the absorber; 13. Protective shell of the absorber. Detailed Implementation

[0023] To better explain and facilitate understanding of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] The present invention provides an aluminum electrolytic cell energy storage system, as shown in Figure 1, including an electrolytic cell heat absorption device 2, which is installed on the aluminum electrolytic cell 1. The heat exchange medium flows through the heat exchange pipeline in the electrolytic cell heat absorption device 2 to exchange heat with the aluminum electrolytic cell 1. Specifically, the electrolytic cell heat absorption device 2 includes multiple absorbers connected in series or parallel, as shown in Figure 2. Each absorber includes an internal heat absorption pipe 12 and an external protective shell 13. The internal heat absorption pipe 12 is made of a thermally conductive material with a high thermal conductivity, such as aluminum, steel, or copper. The heat exchange medium flows through the internal heat absorption pipe 12, which is positioned as close as possible to the heat dissipation area of ​​the side wall of the aluminum electrolytic cell 1. Specifically, the electrolytic cell heat absorption device 2 is distributed in multiple locations on the aluminum electrolytic cell 1, including but not limited to being close to the side shell, close to the steel rod, close to the surface of the covering material, and placed inside the side carbon block. The state of the electrolytic cell heat absorption device 2 when it is close to the side shell is shown in Figure 3, and the state of the electrolytic cell heat absorption device 2 installed inside the side carbon block is shown in Figure 4.

[0025] Multiple absorbers are installed in series or parallel. Along the length of the aluminum electrolysis cell 1, the cell is divided into several areas by a cradle frame. Adjacent cradle frames constitute the same area. Absorbers between different areas are installed in parallel, while absorbers within the same area are installed in series. Specifically, along the length of the aluminum electrolysis cell 1, the cell is divided into several areas by a cradle frame. Adjacent cradle frames constitute the same area. Absorbers between different areas are installed in parallel, while absorbers within the same area are installed in series.

[0026] The electrolytic cell heat absorption device 2 is connected to the waste heat exchanger 6 via a connecting pipe. After absorbing heat from the side and / or top of the aluminum electrolytic cell 1, the heat is transferred to the waste heat exchanger by the heat exchange medium through the connecting pipe. The heat exchange medium includes, but is not limited to, air, heat transfer oil, molten salt, etc. Specifically, the connecting pipe is divided into a cold pipe 3 and a hot pipe 5. The high-temperature heat exchange medium in the electrolytic cell heat absorption device 2 after heat exchange with the aluminum electrolytic cell 1 flows into the waste heat exchanger 6 through the hot pipe 5. A power circulation device 4 is provided on the connecting pipe between the electrolytic cell heat absorption device 2 and the waste heat exchanger 6. After the high-temperature heat exchange medium undergoes heat exchange at the hot end of the waste heat exchanger 6, it becomes a low-temperature heat exchange medium. After being pressurized by the power circulation device 4, it returns to the electrolytic cell heat absorption device 2 through the cold pipe 3 of the connecting pipe. The high-temperature heat exchange medium exchanges heat with the organic working fluid in the waste heat power generation device 8 in the waste heat heat exchanger 6, heating the organic working fluid to high-temperature, high-pressure organic working fluid vapor, which then drives the organic working fluid to generate electricity. The generated electricity is then transmitted to the battery energy storage device 9 for storage. Insulation cotton can be wrapped around the connecting pipes to prevent heat loss. Specifically, the waste heat heat exchanger 6 is connected to the electrolytic cell heat absorption devices 2 of several aluminum electrolytic cells 1 via connecting pipes, and the waste heat power generation device 8 is connected to several waste heat heat exchangers 6. The heat exchange medium circulates between the electrolytic cell heat absorption devices, connecting pipes, and the hot end of the waste heat heat exchanger. When necessary, the electrical energy from the battery energy storage device 9 is transmitted to the aluminum electrolytic cell 1 via the DC bus access device 10. The battery energy storage device can be charged simultaneously or separately by the waste heat power generation device and an external power supply system.

[0027] Waste heat exchanger 6 is connected to waste heat power generation device 8. Waste heat power generation device 8 uses the waste heat from waste heat exchanger 6 to generate electricity. Specifically, one or more waste heat exchangers 6 are configured with one waste heat power generation device 8. The generated electricity is supplied to battery energy storage device 9 and the plant's power grid 7. Battery energy storage device 9 is connected to DC bus access device 10 and is also connected to external power supply system 11. Battery energy storage device is charged simultaneously or individually by waste heat power generation device 8 and external power supply system 11. DC bus access device 10 is also connected to aluminum electrolysis cell 1.

[0028] The battery energy storage device 9 provides load when the electrolytic series cannot obtain sufficient power load due to grid power rationing, during peak periods when grid electricity prices are high, or when there is excess power in the battery energy storage device 9. The battery energy storage device 9 is also charged by the external power supply system 11 when the grid is used as the external power supply system and when the grid is used as the external power supply system during off-peak hours.

[0029] Specifically, each waste heat power generation unit 8 is equipped with one or more battery energy storage devices 9. Each battery energy storage device 9 includes: an input AC power supply with a voltage consistent with the outlet voltage of the waste heat power generation unit 8; and an output DC power supply with a voltage consistent with the DC bus voltage of the electrolytic power supply. The battery energy storage device 9 is equipped with control and protection devices and communicates with the rectifier's current stabilization control system. The battery energy storage device 9 receives electrical energy from the waste heat power generation unit 8 and simultaneously stores a certain amount of electrical energy at off-peak electricity prices, reducing investment in electrical energy during peak electricity prices.

[0030] The control and protection devices include: sending the supplied current value parameters to the rectifier current stabilization control system; receiving voltage regulation commands sent by the rectifier current stabilization control system; and receiving emergency shutdown commands sent by the rectifier current stabilization control system to stop supplying power to the DC bus.

[0031] The battery energy storage device 9 receives electrical energy from the waste heat power generation device 8 and stores electrical energy at off-peak electricity prices. The amount of electrical energy stored by the battery energy storage device 9 at off-peak electricity prices is determined based on the AC backup power supply of the electrolysis area and is used as backup power reserve for the area.

[0032] Specifically, an electrolysis series shares a DC bus access device 10. All battery energy storage devices 9 are connected to the DC bus access device 10. The DC bus access device 10 is connected to the DC power supply bus of the electrolysis through an aluminum bus connection, thereby supplying power to the electrolysis cells. At the connection point between the DC power supply bus and the electrolysis power supply bus, a bus access protection cabinet is installed. The bus access protection cabinet includes: preventing current backflow; and installing an isolation blade to realize power disconnection during maintenance.

[0033] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any modifications, alterations, substitutions, and variations made by those skilled in the art to the above embodiments are within the scope of the present invention.

Claims

1. An energy storage system for an aluminum electrolytic cell, characterized in that: The device includes an electrolytic cell heat absorption device (2), which is installed on the aluminum electrolytic cell (1). The heat exchange medium flows through the heat exchange pipeline in the electrolytic cell heat absorption device (2) and exchanges heat with the aluminum electrolytic cell (1). The electrolytic cell heat absorption device (2) is connected to the waste heat exchanger (6) through a connecting pipeline. The waste heat exchanger (6) is connected to the waste heat power generation device (8). The waste heat power generation device (8) generates electricity using the waste heat of the waste heat exchanger (6). The generated electricity is supplied to the battery energy storage device (9) and the plant power grid (7). The battery energy storage device (9) is connected to the DC bus access device (10). The battery energy storage device (9) is also connected to the external power supply system (11). The battery energy storage device is charged simultaneously or separately by the waste heat power generation device (8) and the external power supply system (11). The DC bus access device (10) is also connected to the aluminum electrolytic cell (1).

2. The aluminum electrolysis cell energy storage system according to claim 1, characterized in that: The battery energy storage device (9) provides load to the outside when the power grid is cut off and the electrolytic series cannot obtain sufficient power load, when the power grid price is at a high price during peak hours, and when there is excess power in the battery energy storage device (9). The battery energy storage device (9) is charged by the external power supply system when the low-priced new energy power supply network is used as the external power supply system, and when the power grid is used as the external power supply system during the off-peak electricity price.

3. The aluminum electrolysis cell energy storage system according to claim 1, characterized in that: A power circulation device (4) is provided on the connecting pipeline between the electrolytic cell heat absorption device (2) and the waste heat exchanger (6).

4. The aluminum electrolysis cell energy storage system according to claim 1, characterized in that: The waste heat exchanger (6) is connected to the electrolytic cell heat absorption device (2) of several aluminum electrolytic cells (1) through connecting pipes, and the waste heat power generation device (8) is connected to several waste heat exchangers (6).

5. The aluminum electrolysis cell energy storage system according to claim 1, characterized in that: The electrolytic cell heat absorption device (2) consists of several heat absorbers connected in series or in parallel, distributed in several positions of the aluminum electrolytic cell (1), including those closely attached to the side shell, closely attached to the steel rod, closely attached to the surface of the covering material, and placed inside the side carbon block.

6. The aluminum electrolysis cell energy storage system according to claim 5, characterized in that: The aluminum electrolysis cell (1) is divided into several regions along the length of the cradle frame. The two adjacent cradle frames are in the same region. The absorbers in different regions are installed in parallel, and the absorbers in the same region are installed in series.

7. The aluminum electrolysis cell energy storage system according to claim 1, characterized in that: Each waste heat power generation device (8) is equipped with one or more battery energy storage devices (9), the battery energy storage device (9) includes: input AC power, the voltage of which is consistent with the output voltage of the waste heat power generation device (8); output DC power, the voltage of which is consistent with the DC bus voltage of the electrolysis power supply.

8. The aluminum electrolysis cell energy storage system according to claim 1, characterized in that: The battery energy storage device (9) is equipped with a control and protection device that communicates with the rectifier current stabilization control system. The control and protection device includes: sending the supplied current value parameters to the rectifier current stabilization control system; receiving the voltage regulation command sent by the rectifier current stabilization control system; and receiving the emergency shutdown command sent by the rectifier current stabilization control system to stop supplying power to the DC bus.

9. The aluminum electrolysis cell energy storage system according to claim 1, characterized in that: The battery energy storage device (9) receives electrical energy from the waste heat power generation device (8) and stores electrical energy at the off-peak electricity price of the power grid. The amount of electrical energy stored by the battery energy storage device (9) at the off-peak electricity price of the power grid is determined according to the amount of AC backup power in the electrolysis area and is used as backup power reserve for the area.

10. An aluminum electrolysis cell energy storage system according to claim 1, characterized in that: An electrolysis series shares a DC bus access device (10). The battery energy storage device (9) is connected to the DC bus access device (10). The DC bus access device (10) is connected to the DC power supply bus of the electrolysis through an aluminum bus connection to supply power to the electrolysis cell. A bus access protection cabinet is set at the connection point between the bus access device and the DC power supply bus. The bus access protection cabinet includes: preventing current backflow; and setting up an isolation knife to realize power disconnection during maintenance.

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