A device system and method based on multi-energy storage in the steel industry

Abstract

The present invention relates to a device system and method based on multi-energy storage in the steel industry, wherein the device system includes a power supply system, an electric load system and an energy storage system; the power supply system includes a new energy power generation system, a gas self-generation system and a power grid; the electric load system includes a steel production process system; the energy storage system includes a thermal energy storage system, a gas tank energy storage system, an air separation energy storage system and a chemical energy storage system. The method adopts the device system. The device system and method based on multi-energy storage in the steel industry provided by the present invention can implant multiple energy storage methods into the steel production process flow, fully utilize and adjust multiple energy storage technologies, increase energy storage capacity, reduce production costs, and improve energy utilization.

Description

Technical Field

[0001] The present invention relates to the field of steel smelting, and in particular to a device system and method based on multi-energy storage in the steel industry. Background Art

[0002] The steel industry is a process-based industry characterized by continuous production, high and fluctuating electricity loads, the generation of associated coal gas and waste heat, and significant energy consumption and carbon emissions. To reduce carbon emissions, steel companies must fully utilize their geographical and regional conditions, both by utilizing waste heat and energy for power generation and by introducing renewable energy sources.

[0003] Internal waste heat and energy generation typically occurs alongside the production process and is a non-stop form of power generation. Currently, steel mills generate two main types of excess gas: blast furnace gas, which primarily powers heating equipment such as hot blast furnaces, sintering machines, and heating furnaces in steelmaking workshops. The other type is converter gas, which is used internally within the steelmaking system. Currently, most steel mills primarily utilize this excess gas for self-generated power, minimizing emissions and avoiding energy waste.

[0004] Introducing renewable energy sources, such as photovoltaic power generation, can lower energy costs and reduce carbon emissions caused by purchasing electricity from outside sources when internal power generation fails to meet production needs. Therefore, fully tapping into renewable energy sources to achieve self-generated and self-sold green electricity within local power grids is becoming a growing trend. However, photovoltaic power generation is not only intermittent but also generates large amounts of power. If power generation exceeds demand, it can easily lead to curtailment, resulting in a waste of resources. Furthermore, external power purchases are necessary to regulate corporate electricity consumption at night or during periods of low sunlight.

[0005] CN114069675A discloses a control system for balancing the electrical load of a steel enterprise. The system is controlled by a self-contained power plant, a public power grid, a load side, an energy management system, an energy storage unit, a resistor, and a battery management system. However, the system can only effectively distribute power through energy management to balance the load, and cannot fully provide a source of electricity from the power supply side, resulting in a high cost.

[0006] CN104035475B discloses a method for automatic control of active power of photovoltaic power stations that takes into account both grid security and minimal abandoned light. This method constructs a quadratic programming problem with the dual objectives of minimizing abandoned light and minimizing deviation in the active load rate of each photovoltaic power station. It uses the interior point method to efficiently solve the problem. While ensuring grid security, it prioritizes the use of photovoltaic resources and takes into account fair scheduling among photovoltaic power stations. However, this method is not suitable for production in the steel industry and still results in a large amount of photovoltaic power wasted.

[0007] Therefore, it is of great significance to provide a device system and method for multi-energy storage and solving the problem of abandoned light that is applicable to the steel industry. Summary of the Invention

[0008] In response to the above problems, the purpose of the present invention is to provide a device system and method based on multi-energy storage in the steel industry. Compared with the existing technology, the device system provided by the present invention can deeply couple the energy storage system, power supply system and steel production process, absorb excess green electricity, and solve the problems of abandoned solar power, fluctuations in the supply of large-capacity new energy, and the contradiction between peak and valley electricity prices of the power grid and the safety and economy of enterprise energy use.

[0009] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a device system based on multi-energy storage in the steel industry, the device system including a power supply system, an electric load system and an energy storage system; the power supply system includes a new energy power generation system, a gas self-generation system and a power grid; the electric load system includes a steel production process system; the energy storage system includes a thermal energy storage system, a gas tank energy storage system, an air separation energy storage system and a chemical energy storage system; the new energy power generation system includes a photovoltaic power generation system; the outlet of the photovoltaic power generation system is connected to the chemical energy storage system; the outlet of the photovoltaic power generation system and the outlet of the chemical energy storage system are both connected to the steel production process system; the outlet of the steel production process system is respectively connected to the thermal energy storage system and the gas tank energy storage system; the outlet of the thermal energy storage system and the outlet of the gas tank energy storage system are both connected to the gas self-generation system; the inlet of the air separation energy storage system is connected to the power supply system; and the outlet of the air separation energy storage system is connected to the steel production process system.

[0011] The present invention deeply couples the power supply system, the electric load system and the energy storage system, wherein the power supply system includes a new energy power generation system, a gas self-generated power generation system and a power grid, the new energy power generation system includes a photovoltaic power generation system, and the energy storage system includes a thermal energy storage system, a gas tank energy storage system, an air separation energy storage system and a chemical energy storage system. It can rely on the process flow of steel production to give full play to the significant advantages of various energy storage technologies such as thermal energy storage, gas tank energy storage, and air separation energy storage in terms of storage capacity and charge and discharge rate, and realize multi-energy storage, long-term energy storage and precise regulation of electrical energy, so as to significantly improve the production efficiency and production benefits of steel enterprises. At the same time, the problem of abandoned light easily caused by large-capacity photovoltaic power generation is solved through a variety of energy storage methods, and energy is released at night or when the light is not strong, further maintaining the safety, stability and economy of electricity use in steel enterprises.

[0012] In the present invention, the new energy power generation system may also be a wind power generation system, and the device system of the present invention is also applicable to the new energy power generation system using wind power generation.

[0013] The chemical energy storage device in the present invention is a storage battery with a capacity of 15%. The outlet of the photovoltaic power generation system in the present invention is connected to the chemical energy storage system, which can store part of the electricity generated by photovoltaic power generation in the energy storage battery.

[0014] Preferably, the outlet of the converter unit in the steel production process system is connected to the gas tank of the gas tank energy storage system.

[0015] Preferably, the outlet of the blast furnace unit and the outlet of the converter unit in the steel production process system are both connected to the heat and energy storage system.

[0016] In the present invention, the gas obtained from the converter unit and the blast furnace unit in the steel production process is fully utilized to store energy. A portion of the gas from the converter unit is stored in a gas holder, that is, this portion of energy is stored in the gas holder in the form of gas; the other portion of the gas from the converter unit and the blast furnace unit enters the heat storage and energy storage system for combustion, and is used to heat the molten salt to obtain high-temperature molten salt, that is, this portion of energy is stored in the form of heat energy in the high-temperature molten salt.

[0017] Preferably, the heat and energy storage system includes a molten salt storage tank, a molten salt heating device, a feed water superheater, and a feed water preheater which are sequentially connected along the molten salt transportation direction.

[0018] Preferably, the feed water superheater is bidirectionally connected to the feed water preheater.

[0019] Preferably, the outlet of the feed water preheater is connected to a molten salt heating device.

[0020] Preferably, the inlets of the molten salt heating device are connected to the converter unit and the blast furnace unit respectively.

[0021] Preferably, the inlet of the feed water preheater is connected to the water inlet pipeline.

[0022] Preferably, the outlet of the feed water superheater is connected to the gas turbine unit of the gas-fired power generation system.

[0023] In the present invention, molten salt enters the molten salt heating device from the molten salt storage tank, and the molten salt is heated by the coal gas from the steel production process system in the molten salt heating device to obtain high-temperature molten salt. The high-temperature molten salt enters the feed water superheater and the feed water preheater in turn to exchange heat with the medium water to generate high-temperature steam; the high-temperature steam enters the gas turbine unit of the gas self-generation system to generate self-generation.

[0024] Preferably, the air separation energy storage system comprises an air purification unit, a liquid air preparation system and a separation unit connected in sequence along the direction of liquid air preparation.

[0025] Preferably, the liquid air preparation system includes at least two stages of air liquefaction units, for example, one stage, two stages or three stages, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0026] Preferably, the liquid air preparation system includes a first air liquefaction unit and a second air liquefaction unit.

[0027] Preferably, the outlet of the separation unit is connected to a steel production process system.

[0028] In the present invention, the air separation energy storage system utilizes electricity from the power supply system, converting purified air into liquid air in a liquid air preparation system based on the power balance of the power supply system. This system then performs load-shifting energy storage, achieving phased power storage. The resulting liquid air is separated to produce oxygen, which is then fed into the steel production process system for steel production.

[0029] In a second aspect, the present invention provides a method for multi-energy storage in the steel industry, wherein the method adopts the device system described in the first aspect of the present invention;

[0030] The method comprises the following steps:

[0031] (1) Detect the self-generated power of the power supply system and the electric load demand of the electric load system to determine whether the self-generated power is greater than the electric load demand. If not, loop back to the power supply system to detect the self-generated power. If so, enter the energy storage mode;

[0032] (2) After entering the energy storage mode, determine whether the gas volume meets the minimum load of the gas turbine unit. If yes, enter the thermal energy storage mode; if not, enter the air separation energy storage mode and / or gas tank energy storage mode;

[0033] (3) After entering the heat storage mode, it is determined whether the photovoltaic power generation in the power supply system has ended. If not, it enters the heat storage mode and / or the gas tank energy storage mode; if so, the heat storage mode is turned on for the heat release mode, the gas tank energy storage mode is turned on for the release mode, and then the gas self-generation mode is entered.

[0034] The multi-energy storage method provided by the present invention controls and adjusts the self-generated electricity and the electric load demand, wherein the self-generated electricity includes photovoltaic power generation and gas self-generated electricity; the electric load demand includes the electricity required by the steel production process system and the electricity required by the air separation energy storage system (including the electricity required for liquid air preparation); further, a variety of energy is stored through energy storage methods such as thermal storage mode, air separation energy storage mode and gas tank energy storage mode, which can adjust the balance between self-generated electricity such as photovoltaic power generation and gas self-generated electricity and the electric load demand, solve the supply fluctuations after the access of large-capacity new energy, the peak and valley electricity price power supply of the power grid and the energy safety and economy of the enterprise, and effectively solve the problem of abandoned light through multi-energy storage, saving energy while reducing production costs.

[0035] Preferably, the heat and energy storage mode includes: the blast furnace gas generated by the blast furnace unit in the steel production process system and the converter gas recovered by the converter unit enter the molten salt heating device to burn and heat the molten salt to obtain high-temperature molten salt; the high-temperature molten salt enters the molten salt storage tank for energy storage.

[0036] In the present invention, when the self-generated electricity is greater than the required electric load, under the condition of meeting the minimum load of the gas turbine unit, the self-generated electricity by gas is reduced, and the blast furnace gas generated by the blast furnace unit and the converter gas recovered by the converter unit are burned and heated to obtain high-temperature molten salt, that is, part of the energy is stored in the form of thermal energy in the high-temperature molten salt, and heat is released when gas self-generated electricity is needed. The heat and energy storage can fully absorb the surplus energy resources associated with the steel production process, and form the electricity required for production through conversion, thereby achieving the effect of power peak shaving and valley filling, and improving economic efficiency.

[0037] Preferably, the air separation energy storage mode includes: after the air enters the air purification unit for purification, it enters the first air liquefaction unit and the second air liquefaction unit respectively for air separation treatment to obtain liquid air, and the liquid air enters the separation unit for separation to obtain oxygen; the oxygen enters the steel production process system for steelmaking; the electricity for the air separation treatment comes from the power supply system.

[0038] Preferably, the gas tank energy storage mode includes: converter gas recovered from the converter unit in the steel production process system enters the gas tank of the gas tank energy storage system for energy storage.

[0039] In the present invention, when the self-generated electricity is greater than the electric load demand and does not meet the minimum load condition of the gas turbine unit, the air separation energy storage mode and the gas tank energy storage mode are entered. The air separation energy storage mode is to purify the air and then perform air separation to prepare liquid air. The prepared liquid air is further separated to obtain oxygen for use in steel production. After entering the air separation energy storage mode, it further enters the electric load transfer energy storage. After the electric load transfer energy storage, the cycle returns to the electric load demand detection. The air separation energy storage mode of the present invention can not only be used according to the power demand of the power supply system, but also can be used according to the electricity price. That is, when the electricity price is low during valley electricity, the air separation energy storage mode is selected to store part of the energy, and then release the energy on demand, thereby reducing the system's demand for peak electricity, realizing peak shaving and valley filling, and effectively improving the energy conversion efficiency and operating economy of the air separation system. The gas tank energy storage mode is to store the gas of the converter unit in the gas tank for energy storage, and release it when gas self-generation is required.

[0040] Preferably, the gas self-generation mode includes: the shut-off valve of the molten salt storage tank is opened, the molten salt enters the molten salt heating device from the molten salt storage tank, the gas in the gas tank enters the molten salt heating device to burn and heat the molten salt to obtain high-temperature molten salt; the high-temperature molten salt enters the feed water superheater to perform a primary heat exchange with the medium water, and then the high-temperature molten salt enters the feed water preheater to perform a secondary heat exchange with the medium water to obtain high-temperature steam; the high-temperature steam enters the gas turbine unit of the gas self-generation system to generate self-powered electricity.

[0041] As a preferred technical solution of the second aspect of the present invention, the method comprises the following steps:

[0042] (1) Detect the self-generated power of the power supply system and the electric load demand of the electric load system to determine whether the self-generated power is greater than the electric load demand. If not, loop back to the power supply system to detect the self-generated power. If so, enter the energy storage mode;

[0043] (2) After entering the energy storage mode, determine whether the gas volume meets the minimum load of the gas turbine unit. If yes, enter the thermal energy storage mode; if not, enter the air separation energy storage mode and / or gas tank energy storage mode;

[0044] The heat and energy storage mode includes: the blast furnace gas generated by the blast furnace unit and the converter gas recovered by the converter unit in the steel production process system enter the molten salt heating device to burn and heat the molten salt to obtain high-temperature molten salt; the high-temperature molten salt enters the molten salt storage tank for energy storage;

[0045] The air separation energy storage mode includes: after air enters the air purification unit for purification, it enters the first air liquefaction unit and the second air liquefaction unit for air separation treatment to obtain liquid air, and the liquid air enters the separation unit for separation to obtain oxygen; the oxygen enters the steel production process system for steelmaking; the electricity for the air separation treatment comes from the power supply system;

[0046] The gas tank energy storage mode includes: converter gas recovered from the converter unit in the steel production process system enters the gas tank of the gas tank energy storage system for energy storage;

[0047] (3) After entering the heat storage mode, it is determined whether the photovoltaic power generation in the power supply system has ended. If not, it enters the heat storage mode and / or the gas tank energy storage mode; if so, the heat storage system starts the heat release mode, the gas tank energy storage system starts the release mode, and then enters the gas self-generation mode;

[0048] The gas self-generation mode includes: the shut-off valve of the molten salt storage tank is opened, the molten salt enters the molten salt heating device from the molten salt storage tank, the gas in the gas tank enters the molten salt heating device to burn and heat the molten salt to obtain high-temperature molten salt; the high-temperature molten salt enters the feed water superheater to perform a primary heat exchange with the medium water, and then the high-temperature molten salt enters the feed water preheater to perform a secondary heat exchange with the medium water to obtain high-temperature steam; the high-temperature steam enters the gas turbine unit of the gas self-generation system to generate self-powered electricity.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] (1) The device system based on multi-energy storage in the steel industry provided by the present invention can implant various energy storage methods into the steel production process, fully utilize and adjust various energy storage technologies, increase energy storage capacity, reduce production costs, and improve energy utilization.

[0051] (2) The method of multi-energy storage based on the steel industry provided by the present invention fully utilizes the significant advantages of various energy storage technologies such as thermal energy storage, gas tank energy storage, and air separation energy storage in terms of storage capacity and charge and discharge rate, realizes multi-energy storage, long-term energy storage and precise regulation of electricity consumption, achieves the effect of power peak shaving and valley filling, and improves the production efficiency and production benefits of steel enterprises.

[0052] (3) The method of multi-energy storage based on the steel industry provided by the present invention solves the problem of abandoned light that is easily caused by large-capacity photovoltaic power generation through multiple energy storage methods, and releases energy at night or when the light is not strong, further maintaining the safety, stability and economy of electricity use in steel enterprises. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 Schematic diagram of the device system based on multi-energy storage in the steel industry described in Example 1 of the present invention;

[0054] Figure 2 is a schematic diagram of the heat and energy storage system described in Example 1 of the present invention;

[0055] Figure 3 is a schematic diagram of the air separation energy storage system described in Example 1 of the present invention;

[0056] Figure 4 This is a flow chart of the method for multi-energy storage based on the steel industry described in Example 1 of the present invention.

[0057] Among them, 1-power supply system; 2-steel production process system; 3-photovoltaic power generation system; 4-gas self-generation system; 5-power grid; 6-heat storage system; 7-gas tank energy storage system; 8-air separation energy storage system; 9-chemical energy storage system; 10-converter unit; 11-blast furnace unit; 12-molten salt storage tank; 13-molten salt heating device; 14-feed water superheater; 15-feed water preheater; 16-water inlet pipeline; 17-molten salt storage tank shut-off valve; 18-air purification unit; 19-separation unit; 20-first air liquefaction unit; 21-second air liquefaction unit. DETAILED DESCRIPTION

[0058] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0059] Example 1

[0060] This embodiment provides a device system based on multi-energy storage in the steel industry, such as Figure 1 As shown, the device system includes a power supply system 1, an electric load system and an energy storage system; the power supply system 1 includes a new energy power generation system, a gas self-generation system 4 and a power grid 5; the electric load system includes a steel production process system 2; the energy storage system includes a thermal energy storage system 6, a gas tank energy storage system 7, an air separation energy storage system 8 and a chemical energy storage system 9; the new energy power generation system includes a photovoltaic power generation system 3;

[0061] The outlet of the photovoltaic power generation system 3 is connected to the chemical energy storage system 9; the outlet of the photovoltaic power generation system 3 and the outlet of the chemical energy storage system 9 are both connected to the steel production process system 2; the outlet of the steel production process system 2 is respectively connected to the thermal energy storage system 6 and the gas tank energy storage system 7; the outlet of the thermal energy storage system 6 and the outlet of the gas tank energy storage system 7 are both connected to the gas self-generation system 4; the inlet of the air separation energy storage system 8 is connected to the power supply system 1; the outlet of the air separation energy storage system 8 is connected to the steel production process system 2; the outlet of the converter unit 10 in the steel production process system 2 is connected to the gas tank of the gas tank energy storage system 7; the outlet of the blast furnace unit 11 and the outlet of the converter unit 10 in the steel production process system 2 are both connected to the thermal energy storage system 6;

[0062] like Figure 2 As shown, the heat and energy storage system 6 includes a molten salt storage tank 12, a molten salt heating device 13, a feed water superheater 14, and a feed water preheater 15, which are sequentially connected along the molten salt transportation direction; the feed water superheater 14 is bidirectionally connected to the feed water preheater 15; the outlet of the feed water preheater 15 is connected to the molten salt heating device 13; the inlet of the molten salt heating device 13 is respectively connected to the converter unit 10 and the blast furnace unit 11; the inlet of the feed water preheater 15 is connected to the water inlet pipeline 16; the outlet of the feed water superheater 14 is connected to the gas turbine unit of the gas self-generating system 4;

[0063] like Figure 3 As shown, the air separation energy storage system 8 is connected in sequence along the direction of liquid air preparation to an air purification unit 18, a liquid air preparation system and a separation unit 19; the liquid air preparation system includes a first air liquefaction unit 20 and a second air liquefaction unit 21; the outlet of the separation unit 19 is connected to the steel production process system 2.

[0064] This embodiment also provides a method for multi-energy storage based on the steel industry, which uses the above-mentioned device system, such as Figure 4 As shown, the method includes the following steps:

[0065] (1) Detecting the self-generated power of the power supply system 1 and the electric load demand of the electric load system, and determining whether the self-generated power is greater than the electric load demand. If not, looping back to the power supply system 1 to detect the self-generated power. If so, entering the energy storage mode;

[0066] (2) After entering the energy storage mode, determine whether the gas volume meets the minimum load of the gas turbine unit. If yes, enter the thermal energy storage mode; if not, enter the air separation energy storage mode and the gas tank energy storage mode;

[0067] The heat and energy storage mode includes: the blast furnace gas generated by the blast furnace unit 11 and the converter gas recovered by the converter unit 10 in the steel production process system 2 enter the molten salt heating device 13 to burn and heat molten salt to obtain high-temperature molten salt; the high-temperature molten salt enters the molten salt storage tank 12 for energy storage;

[0068] The air separation energy storage mode includes: after air enters the air purification unit 18 for purification, it enters the first air liquefaction unit 20 and the second air liquefaction unit 21 for air separation treatment to obtain liquid air. The liquid air enters the separation unit 19 for separation to obtain oxygen; the oxygen enters the steel production process system 2 for steelmaking; the electricity generated by the air separation treatment comes from the power supply system 1; after the air separation energy storage mode, it further enters the power load transfer energy storage, and after entering the power load transfer energy storage, it circulates back to the power load demand for detection;

[0069] The gas tank energy storage mode includes: the converter gas recovered from the converter unit 10 in the steel production process system 2 enters the gas tank of the gas tank energy storage system 7 for energy storage;

[0070] (3) After entering the heat storage mode, it is determined whether the photovoltaic power generation in the power supply system 1 is completed. If not, it enters the heat storage mode and the gas tank energy storage mode; if so, the heat storage system 6 starts the heat release mode, the gas tank energy storage system 7 starts the release mode, and then enters the gas self-generation mode;

[0071] The gas self-generation mode includes: the molten salt storage tank shut-off valve 17 is opened, the molten salt enters the molten salt heating device 13 from the molten salt storage tank 12, the gas in the gas tank enters the molten salt heating device 13 to burn and heat the molten salt to obtain high-temperature molten salt; the high-temperature molten salt enters the feed water superheater 14 to perform a primary heat exchange on the medium water, and then the high-temperature molten salt enters the feed water preheater 15 to perform a secondary heat exchange on the medium water to obtain high-temperature steam; the high-temperature steam enters the gas turbine unit of the gas self-generation system 4 to generate self-power.

[0072] The above operations complete the multi-energy storage based on the steel industry.

[0073] In this embodiment, the capacities and efficiencies of the chemical energy storage system, the gas tank energy storage system, the thermal energy storage system, and the air separation energy storage system are shown in Table 1.

[0074] Table 1

[0075] type Chemical energy storage Gas tank energy storage Heat and energy storage Air separation energy storage total Capacity (10,000 kW·h) 5 20 5 14 44 Proportion (%) 11.3 45.5 11.3 31.8 - efficiency(%) 0.85 0.9 0.80 0.78 -

[0076] In Table 1, “-” indicates that the data is not available.

[0077] As can be seen from Table 1, the device system and method provided in this embodiment can recover and store 440,000 kW·h of energy. In a typical power generation system, the problem of abandoned solar power results in a loss of 572,000 kW·h. This shows that the device system and method provided by the present invention can significantly alleviate the problem of abandoned solar power. On this basis, further increasing the energy storage system of this embodiment can solve the problem of abandoned solar power.

[0078] In summary, the device system and method provided by the present invention can implant various energy storage methods into the steel production process, fully utilize and adjust various energy storage technologies, increase energy storage capacity, reduce production costs, improve energy utilization, and significantly solve the problem of abandoned light.

[0079] The applicant declares that the above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the scope of protection and disclosure of the present invention.

Claims

1. A method based on multi-energy storage in the steel industry, characterized in that: The method comprises the following steps: (1) Detect the self-generated power of the power supply system and the power load demand of the power load system to determine whether the self-generated power is greater than the power load demand. If not, loop back to the power supply system to detect the self-generated power. If yes, enter the energy storage mode; (2) After entering the energy storage mode, determine whether the gas volume meets the minimum load of the gas turbine unit. If yes, enter the thermal energy storage mode; if not, enter the air separation energy storage mode and / or the gas tank energy storage mode; (3) After entering the thermal energy storage mode, it is determined whether the photovoltaic power generation in the power supply system has ended. If not, it enters the thermal energy storage mode and / or the gas tank energy storage mode; if yes, the thermal energy storage system starts the heat release mode, the gas tank energy storage system starts the release mode, and then enters the gas self-generation mode; The method is carried out using a device system based on multi-energy storage in the steel industry, the device system comprising a power supply system, an electric load system and an energy storage system; The power supply system includes a new energy power generation system, a gas self-generation system and a power grid; The electrical load system includes a steel production process system; The energy storage system includes a thermal energy storage system, a gas tank energy storage system, an air separation energy storage system and a chemical energy storage system; The new energy power generation system includes a photovoltaic power generation system; The outlet of the photovoltaic power generation system is connected to the chemical energy storage system; the outlet of the photovoltaic power generation system and the outlet of the chemical energy storage system are both connected to the steel production process system; The outlet of the steel production process system is connected to the heat storage system and the gas tank storage system respectively; The outlet of the heat storage system and the outlet of the gas tank energy storage system are both connected to the gas self-generating system; The inlet of the air separation energy storage system is connected to the power supply system; The outlet of the air separation energy storage system is connected to the steel production process system.

2. The method according to claim 1, characterized in that The outlet of the converter unit in the steel production process system is connected to the gas tank of the gas tank energy storage system.

3. The method according to claim 1, characterized in that The outlet of the blast furnace unit and the outlet of the converter unit in the steel production process system are both connected to the heat and energy storage system.

4. The method according to claim 1, characterized in that The heat and energy storage system comprises a molten salt storage tank, a molten salt heating device, a feed water superheater, and a feed water preheater which are sequentially connected along the molten salt conveying direction.

5. The method according to claim 4, characterized in that The feed water superheater is bidirectionally connected to the feed water preheater.

6. The method according to claim 4, characterized in that The outlet of the feedwater preheater is connected to a molten salt heating device.

7. The method according to claim 4, characterized in that The inlets of the molten salt heating device are respectively connected to the converter unit and the blast furnace unit.

8. The method according to claim 4, characterized in that The inlet of the feed water preheater is connected to the water inlet pipeline.

9. The method according to claim 4, characterized in that The outlet of the feed water superheater is connected to the gas turbine unit of the gas self-generating system.

10. The method according to claim 1, characterized in that The air separation energy storage system comprises an air purification unit, a liquid air preparation system and a separation unit which are sequentially connected along the direction of preparing liquid air.

11. The method according to claim 10, characterized in that The liquid air preparation system comprises at least two stages of air liquefaction units.

12. The method according to claim 10, characterized in that The liquid air preparation system includes a first air liquefaction unit and a second air liquefaction unit.

13. The method according to claim 10, characterized in that The outlet of the separation unit is connected to the steel production process system.

14. The method according to claim 1, characterized in that The heat storage and energy storage mode includes: the blast furnace gas generated by the blast furnace unit and the converter gas recovered by the converter unit in the steel production process system enter the molten salt heating device to burn and heat the molten salt to obtain high-temperature molten salt; the high-temperature molten salt enters the molten salt storage tank for energy storage.

15. The method according to claim 1, characterized in that The air separation energy storage mode includes: after the air enters the air purification unit for purification, it enters the first air liquefaction unit and the second air liquefaction unit respectively for air separation treatment to obtain liquid air, and the liquid air enters the separation unit for separation to obtain oxygen; the oxygen enters the steel production process system for steelmaking; the electricity for the air separation treatment comes from the power supply system.

16. The method according to claim 1, characterized in that The gas holder energy storage mode includes: the converter gas recovered from the converter unit in the steel production process system enters the gas holder of the gas holder energy storage system for energy storage.

17. The method according to claim 1, characterized in that The gas self-generation mode includes: the shut-off valve of the molten salt storage tank is opened, the molten salt enters the molten salt heating device from the molten salt storage tank, the gas in the gas tank enters the molten salt heating device to burn and heat the molten salt to obtain high-temperature molten salt; the high-temperature molten salt enters the feed water superheater to perform a primary heat exchange with the medium water, and then the high-temperature molten salt enters the feed water preheater to perform a secondary heat exchange with the medium water to obtain high-temperature steam; the high-temperature steam enters the gas turbine unit of the gas self-generation system to generate self-generation.

18. The method according to claim 1, characterized in that The method comprises the following steps: (1) Detect the self-generated power of the power supply system and the power load demand of the power load system to determine whether the self-generated power is greater than the power load demand. If not, loop back to the power supply system to detect the self-generated power. If yes, enter the energy storage mode; (2) After entering the energy storage mode, determine whether the gas volume meets the minimum load of the gas turbine unit. If yes, enter the thermal energy storage mode; if not, enter the air separation energy storage mode and / or the gas tank energy storage mode; The heat storage and energy storage mode includes: the blast furnace gas generated by the blast furnace unit in the steel production process system and the converter gas recovered by the converter unit enter the molten salt heating device to burn and heat the molten salt to obtain high-temperature molten salt; the high-temperature molten salt enters the molten salt storage tank for energy storage; The air separation energy storage mode includes: after the air enters the air purification unit for purification, it enters the first air liquefaction unit and the second air liquefaction unit for air separation treatment to obtain liquid air, and the liquid air enters the separation unit for separation to obtain oxygen; the oxygen enters the steel production process system for steelmaking; the electricity for the air separation treatment comes from the power supply system; The gas tank energy storage mode includes: the converter gas recovered from the converter unit in the steel production process system enters the gas tank of the gas tank energy storage system for energy storage; (3) After entering the thermal energy storage mode, it is determined whether the photovoltaic power generation in the power supply system has ended. If not, it enters the thermal energy storage mode and / or the gas tank energy storage mode; if yes, the thermal energy storage system starts the heat release mode, the gas tank energy storage system starts the release mode, and then enters the gas self-generation mode; The gas self-generation mode includes: the shut-off valve of the molten salt storage tank is opened, the molten salt enters the molten salt heating device from the molten salt storage tank, the gas in the gas tank enters the molten salt heating device to burn and heat the molten salt to obtain high-temperature molten salt; the high-temperature molten salt enters the feed water superheater to perform a primary heat exchange with the medium water, and then the high-temperature molten salt enters the feed water preheater to perform a secondary heat exchange with the medium water to obtain high-temperature steam; the high-temperature steam enters the gas turbine unit of the gas self-generation system to generate self-generation.

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