Energy power system for improving utilization rate of electric furnace

Abstract

The utility model relates to an energy power system for improving the utilization rate of an electric furnace. The energy power system comprises an air compression unit connected with a municipal power grid. According to the energy storage and release unit, a gas inlet of a gas-liquid heat exchanger is connected with an air compression unit through a pipeline, a gas outlet is connected with a gas storage device through a pipeline, a liquid inlet is connected with a low-temperature storage tank through a pipeline, and a liquid outlet is connected with a high-temperature storage tank through a pipeline; the high-temperature storage tank is further connected with the electric furnace waste heat boiler through a steam pipeline. A liquid inlet of the gas-liquid reheater is connected with the high-temperature storage tank through a pipeline, a liquid outlet is connected with the low-temperature storage tank through a pipeline, and a gas inlet is connected with the gas storage device through a pipeline; the power generation unit comprises an expansion machine, the expansion machine communicates with a gas outlet of the gas-liquid reheater, and high-temperature air fed by the gas-liquid reheater does work through the expansion machine to generate plant power. Municipal valley electricity, green electricity, electric furnace waste heat and a compressed air energy storage system are combined, and stable and low-cost electricity is provided for electric furnace production at the peak time.

Description

Technical Field

[0001] The utility model relates to the field of metallurgical technology and engineering technology, in particular to an energy power system for improving the utilization rate of an electric furnace. Background Art

[0002] my country's annual crude steel output continues to rank first in the world, and most crude steel production adopts long-process smelting, which leads to high carbon emissions in the steel industry. Among carbon reduction technologies, short-process steelmaking has gradually occupied an important position with its low carbon emissions (unit carbon emissions are 1 / 3 of long-process steelmaking).

[0003] However, short-process steelmaking is mainly based on power-consuming electric furnace smelting. When smelting in an electric furnace, the electricity consumption per ton of steel is very high. Therefore, the smelting of a ton of steel is subject to the gradually increasing peak-valley price difference of electricity consumption. The electricity cost of electric furnaces during peak hours of the power grid continues to rise. Many companies implement "peak-avoiding and valley-going" production and suspend production during peak hours, resulting in low capacity utilization of electric furnaces.

[0004] In order to solve the above-mentioned problems, currently, low-parameter waste heat boilers and steam turbine generator sets are mainly used to provide part of the electricity for electric furnace production. Although this can increase the utilization rate of electric furnace capacity to a certain extent, it also reduces its production cost. However, due to the intermittent nature of waste heat from electric furnaces, the waste heat boilers currently used mainly produce low-parameter saturated steam. After configuring a steam turbine alone, the power generation efficiency is low and the energy utilization rate is low. At the same time, electric furnaces are often shut down during peak hours, and steam turbines cannot match their frequent start-stop conditions, resulting in the fact that many companies have configured electric furnace waste heat recovery systems that have not been put into use, resulting in energy waste. Therefore, it is very necessary to provide an energy power system that can improve the productivity of electric furnaces and reduce their production costs. Utility Model Content

[0005] The purpose of the utility model is to overcome the above-mentioned problems existing in the prior art. The utility model proposes a new energy power system solution, which combines municipal valley electricity, green electricity, electric furnace waste heat and compressed air energy storage system to provide stable and low-cost electricity for electric furnace production during peak hours, thereby improving the productivity of electric furnaces and reducing their production costs, and promoting the promotion of electric furnace short-process smelting technology.

[0006] The utility model provides an energy power system for improving the utilization rate of an electric furnace, comprising:

[0007] An air compression unit is connected to the municipal power grid and is used to compress the air and output high-temperature air during the off-peak hours of the municipal power grid;

[0008] The energy storage and release unit includes a gas-liquid heat exchanger, a gas storage device, a gas-liquid reheater, a high-temperature storage tank and a low-temperature storage tank, wherein:

[0009] The gas-liquid heat exchanger is used for heat exchange and energy storage between the high-temperature air output by the air compression unit and the low-temperature liquid working medium. Its gas inlet is connected to the air compression unit through a pipeline, the gas outlet is connected to the gas storage device through a pipeline, the liquid inlet is connected to the low-temperature storage tank through a pipeline, and the liquid outlet is connected to the high-temperature storage tank through a pipeline;

[0010] The high-temperature storage tank is also connected to the electric furnace waste heat boiler through a steam pipeline, and the electric furnace waste heat boiler is used to supplement intermittent waste heat to adjust the temperature of the high-temperature liquid working medium after heat exchange;

[0011] The gas-liquid reheater is used to release heat between the low-temperature air in the low-temperature storage tank and the high-temperature liquid working medium in the high-temperature storage tank. Its liquid inlet is connected to the high-temperature storage tank through a pipeline, its liquid outlet is connected to the low-temperature storage tank through a pipeline, and its gas inlet is connected to the gas storage device through a pipeline.

[0012] The power generation unit includes an expander, which is connected to the gas outlet of the gas-liquid reheater. The high-temperature air sent into the gas-liquid reheater works through the expander to generate plant electricity.

[0013] Preferably, the air compression unit is also connected to a photovoltaic power station, which is arranged in parallel with the municipal power grid and connected to the air compression unit through a grid line, and a dual power switching system is provided on the grid line.

[0014] Preferably, the factory electricity generated by the energy power system is incorporated into the factory power grid, and the factory power grid is electrically connected to the electric furnace.

[0015] Preferably, the air compression unit comprises a plurality of compressor motors and a plurality of compressors, each compressor corresponding to each compressor motor one by one and connected by a coupling;

[0016] The power generation unit comprises an expander and a generator, the generator and the expander are coaxially arranged and connected by a coupling; the compressor and the gas-liquid heat exchanger, as well as the gas-liquid reheater and the expander are all connected by pipelines.

[0017] Preferably, the expander is an air turbine for converting the thermal energy and potential energy of the air fed into the expander into mechanical energy.

[0018] Preferably, pipeline pumps and control valves are provided on the pipeline connecting the low-temperature storage tank and the liquid inlet of the gas-liquid heat exchanger and on the pipeline connecting the liquid outlet of the gas-liquid heat exchanger and the high-temperature storage tank.

[0019] Preferably, all the pipelines are provided with control valves.

[0020] Preferably, all the pipelines are made of carbon steel.

[0021] Preferably, the gas storage device is a plurality of groups of pressure vessels, the plurality of groups of pressure vessels are connected in parallel through pipelines, and the plurality of groups of pressure vessels are connected to the gas outlet of the gas-liquid heat exchanger and the gas inlet of the gas-liquid reheater.

[0022] Preferably, the electric furnace is also connected to the municipal power grid to provide backup electricity for the electric furnace during peak hours of the municipal power grid.

[0023] Compared with the prior art, the beneficial effects of the utility model are:

[0024] 1. The utility model provides an energy power system for improving the utilization rate of electric furnaces, which is equipped with an adiabatic compressed air energy storage technology coupled with the waste heat of the electric furnace, and is planned and designed with the goal of optimal economy. After adopting this system solution, the waste heat of the electric furnace does not need to be separately configured with a low-parameter saturated steam generator set, but can be directly used to heat the high-temperature hot water in the high-temperature storage tank in the energy storage and release unit, thereby improving the utilization rate of low-parameter waste heat. The matching compressed air energy storage system stores valley electricity and releases peak electricity, which moves low-cost valley electricity to peak hours, reduces the peak electricity cost of the electric furnace, and thus reduces the shutdown rate of the electric furnace and increases the production capacity of the electric furnace.

[0025] 2. The utility model couples adiabatic compressed air energy storage technology with the electric furnace production power system and the intermittent waste heat of the electric furnace with the air compression unit and the energy storage and release unit to improve the electricity-to-electricity conversion efficiency of the energy storage system; the air compression unit and the energy storage and release unit "valley storage and peak release" solve the problem of high electricity costs during peak hours of electric furnace smelting, improve the utilization rate of the electric furnace, and enhance the competitiveness of the enterprise.

[0026] 3. The utility model converts valley electricity, green electricity, etc. into air compression and energy storage and release units for storage, and compresses air energy storage to release electricity during the peak hours of the power grid to supply power for electric furnace production, smoothing the impact of peak and valley time-sharing on corporate electricity consumption, ensuring the continuity of electric furnace production, and improving the utilization rate of electric furnaces.

[0027] 4. The utility model replenishes all intermittent steam recovered by the electric furnace waste heat boiler into the compressed air energy storage high-temperature heat storage tank to heat the inlet temperature of the energy storage system expander, improve the energy storage power generation efficiency, and improve the economy of the energy storage system.

[0028] 5. The power generation efficiency of the expander of the utility model is much higher than that of the low-parameter steam turbine, which can improve the effective utilization rate of low-quality parameter steam. At the same time, after the waste heat is added to the energy storage system, the investment in heat accumulators, steam turbine generator sets, etc. can be reduced.

[0029] 6. The energy power system for improving the utilization rate of electric furnaces proposed in the utility model combines green electricity, industrial waste heat, air compression units and energy storage and release units to provide stable and low-cost electricity for the smelting process while improving energy utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of an energy power system for improving the utilization rate of an electric furnace according to the utility model. Figure 1 ;

[0031] Figure 2 This is a schematic diagram of an energy power system for improving the utilization rate of an electric furnace according to the utility model. Figure 2 .

[0032] Description of reference numerals:

[0033] 1. Electric furnace, 2. Electric furnace waste heat boiler, 3. Municipal power grid, 4. Photovoltaic power station, 5. Factory power grid, 6. Compressor motor, 7. Compressor, 8. Gas-liquid heat exchanger, 9. Gas storage device, 10. Gas-liquid reheater, 11. High-temperature storage tank, 12. Low-temperature storage tank, 13. Expander, 14. Generator, 15, 16, 17, 18 are all power grid lines, 19 the first high-temperature compressed air pipeline, 20 the first low-temperature compressed air pipeline, 21 the second low-temperature compressed air pipeline, 22 the second high-temperature compressed air pipeline, 100. the first high-temperature hot water pipeline, 110. the second high-temperature hot water pipeline, 120. the first low-temperature hot water pipeline, 130. the second low-temperature hot water pipeline, 200. Electric furnace flue gas pipeline, 140. Electric furnace waste heat steam pipeline. DETAILED DESCRIPTION

[0034] The following is combined with Figure 1-2 , the specific implementation of the utility model is described in detail, but it should be understood that the protection scope of the utility model is not limited by the specific implementation. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.

[0035] The inventors found that due to the intermittent waste heat of electric furnaces, the waste heat boilers currently used mainly produce low-parameter saturated steam. After configuring a steam turbine alone, the power generation efficiency is low and the energy utilization rate is low. At the same time, electric furnaces are often shut down during peak hours, and steam turbines cannot match their frequent start-stop conditions, resulting in many companies configuring electric furnace waste heat recovery systems that are not put into use, resulting in energy waste.

[0036] In view of this, the purpose of the utility model is to provide an energy power system for improving the utilization rate of electric furnaces, so as to solve the problems of low utilization rate of steel electric furnace production and low utilization rate of energy power systems, and to achieve the effect of improving the utilization rate of electric furnaces and "peak shaving and valley filling" to help the local power grid operate stably.

[0037] In order to solve the problems existing in the above-mentioned prior art, the utility model provides an energy power system for improving the utilization rate of an electric furnace.

[0038] See attached Figure 1-2As shown, an energy power system for improving the utilization rate of an electric furnace provided in the embodiment includes an electric furnace waste heat boiler 2, the electric furnace waste heat boiler 2 is connected to the electric furnace 1 through an electric furnace flue gas pipeline 200, and the electric furnace waste heat boiler 2 is used to recover the intermittent steam generated by the electric furnace 1, and also includes:

[0039] An air compression unit is connected to the municipal power grid 3 via a power grid line 17, and is used to compress compressed air and output high-temperature air when the municipal power grid 3 is off-peak;

[0040] The energy storage and release unit includes a gas-liquid heat exchanger 8, a gas storage device 9, a gas-liquid reheater 10, a high-temperature storage tank 11 and a low-temperature storage tank 12, wherein:

[0041] The gas-liquid heat exchanger 8 is used for heat exchange and energy storage between the high-temperature air output by the air compression unit and the low-temperature liquid working medium. The gas inlet of the gas-liquid heat exchanger 8 is connected to the air compression unit through the first high-temperature compressed air pipeline 19, the gas outlet of the gas-liquid heat exchanger 8 is connected to the gas storage device 9 through the first low-temperature compressed air pipeline 20, the liquid inlet of the gas-liquid heat exchanger 8 is connected to the low-temperature storage tank 12 through the second low-temperature hot water pipeline 130, and the liquid outlet of the gas-liquid heat exchanger 8 is connected to the high-temperature storage tank 11 through the first high-temperature hot water pipeline 100, so that the high-temperature air generated by the air compression unit and the low-temperature hot water sent into the low-temperature storage tank 12 are heat exchanged in the gas-liquid heat exchanger 8, and the low-temperature gas after heat exchange is sent to the gas storage device 9, and the intermittent waste heat added by the electric furnace waste heat boiler 2 and the high-temperature liquid after heat exchange are stored in the high-temperature storage tank 11 for heat storage;

[0042] The high-temperature storage tank 11 is supplemented with intermittent waste heat to adjust the temperature of the high-temperature liquid working medium after heat exchange. High-temperature hot water is stored in the high-temperature storage tank 11. The high-temperature storage tank 11 is also connected to the electric furnace waste heat boiler 2 through the electric furnace waste heat steam pipeline 140, which is used to recover and store the steam of the electric furnace waste heat boiler 2, and use the recovered steam to increase the temperature of the high-temperature hot water in the high-temperature storage tank 11;

[0043] The low temperature storage tank 12 is used to store low temperature hot water;

[0044] The gas storage device 9 is used to store low-temperature gas;

[0045] The gas-liquid reheater 10 is used to perform heat exchange and energy release between the low-temperature air in the low-temperature storage tank 12 and the high-temperature liquid working medium in the high-temperature storage tank 11. The liquid inlet of the gas-liquid reheater 10 is connected to the high-temperature storage tank 11 through the second high-temperature hot water pipeline 110, and the liquid outlet of the gas-liquid reheater 10 is connected to the low-temperature storage tank 12 through the first low-temperature hot water pipeline 120. The gas inlet of the gas-liquid reheater 10 is connected to the second low-temperature compressed air pipeline 21 of the gas storage device 9, so that the high-temperature hot water in the high-temperature storage tank 11 and the low-temperature air in the gas storage device 9 are heat exchanged in the gas-liquid reheater 10, and the low-temperature liquid after heat exchange is sent to the low-temperature storage tank 12, and the low-temperature gas after heat exchange absorbs the heat released by the high-temperature liquid to become high-temperature air;

[0046] The power generation unit includes an expander 13, which is connected to the outlet of the gas-liquid reheater 10 through a second high-temperature compressed air pipeline 22. The high-temperature air sent into the gas-liquid reheater 10 passes through the expander 13 to do work to generate plant electricity.

[0047] Working principle:

[0048] During the air compression period, the air compression unit is powered by the municipal power grid 3 during the off-peak hours. After the 200°C high-temperature air generated by the air compression unit is heat exchanged with the 50°C low-temperature hot water sent from the low-temperature storage tank 12 in the gas-liquid heat exchanger 8, the air temperature is reduced to 30°C. At this time, the cold air reduced to 30°C enters the gas storage device 9 for storage; the 50°C low-temperature hot water absorbs the energy of the high-temperature air and becomes high-temperature hot water and enters the high-temperature storage tank 11 for storage, realizing the storage of compression heat. The 200°C low-temperature saturated steam produced by the electric furnace waste heat boiler 2 is sent to the high-temperature storage tank 11 through the electric furnace waste heat steam pipeline 140 to increase the temperature of the hot water in the high-temperature storage tank 11.

[0049] During the expansion power generation, the high-temperature hot water stored in the high-temperature storage tank 11 and the low-temperature air at 30°C stored in the gas storage device 9 exchange heat and release energy in the gas-liquid reheater 10. The high-temperature air at 170°C produced after the heat exchange enters the expander 13 to generate power, and the low-temperature hot water at 50°C produced after the heat exchange is sent back to the low-temperature storage tank 12 for storage.

[0050] The adiabatic compressed air energy storage technology is coupled with the electric furnace production power system and the intermittent waste heat of the electric furnace is coupled with the compressed air energy storage system to improve the electricity-to-electricity conversion efficiency of the energy storage system. The "valley storage and peak release" of the compressed air energy storage system solves the problem of high electricity costs during peak hours of electric furnace smelting, improves the utilization rate of the electric furnace, and enhances the competitiveness of the enterprise.

[0051] Specifically, the air compression unit is also connected to the photovoltaic power station 4, which is arranged in parallel with the municipal power grid 3 and connected to the air compression unit through the power grid line. A dual power switching system is provided on the power grid line for switching at will and powering the air compressor, and can send valley electricity and green electricity into the air compression unit for conversion.

[0052] Specifically, the factory electricity generated by the energy power system is incorporated into the factory power grid 5 , and the factory power grid 5 is electrically connected to the electric furnace 1 .

[0053] Specifically, the air compression unit includes multiple compressor motors 6 and multiple compressors 7, wherein there can be 4 compressor motors 6 and 4 compressors 7, and each compressor 7 corresponds to each compressor motor 6 one by one and is connected by a coupling; the power generation unit includes an expander 13 and a generator 14, and the generator 14 is coaxially arranged with the expander 13 and is connected by a coupling; the compressor 7 and the gas-liquid heat exchanger 8, as well as the reheater 10 and the expander 13 are connected by pipelines.

[0054] Specifically, the expander 13 is an air turbine, which is used to convert the heat energy and potential energy of the air sent into the expander into mechanical energy.

[0055] Specifically, pipeline pumps and control valves are provided on the second low-temperature hot water pipeline 130 connected between the low-temperature storage tank 12 and the liquid inlet of the gas-liquid heat exchanger 8, and on the first high-temperature hot water pipeline 100 connected between the liquid outlet of the gas-liquid heat exchanger 8 and the high-temperature storage tank 11, for adjusting the flow rate of water in the first high-temperature hot water pipeline 100 and the second low-temperature hot water pipeline 130 through the pipeline pumps and control valves.

[0056] Specifically, all pipelines are provided with control valves.

[0057] The first high-temperature compressed air pipeline 19 connected between the air compression unit and the gas-liquid heat exchanger 8 is provided with a first control valve, the second high-temperature hot water pipeline 110 connected between the high-temperature storage tank 11 and the liquid inlet of the gas-liquid reheater 10 is provided with a second control valve, the first low-temperature hot water pipeline 120 connected between the low-temperature storage tank 12 and the liquid outlet of the gas-liquid reheater 10 is provided with a third control valve, and the first low-temperature compressed air pipeline 20 connected between the gas-liquid heat exchanger 8 and the gas inlet of the gas storage device 9 is provided with a fourth control valve; the gas outlet of the gas storage device 9 and the gas inlet of the gas-liquid reheater 10 are connected to each other. A fifth control valve is provided on the second low-temperature compressed air pipeline 21 connected to the body inlet; a sixth control valve is provided on the second high-temperature compressed air pipeline 22 between the gas outlet of the gas-liquid reheater 10 and the expander 13, and a seventh control valve is also provided on the steam pipeline. The purpose of arranging the first control valve, the second control valve, the third control valve, the fourth control valve, the fifth control valve, the sixth control valve and the seventh control valve is to convert and store valley electricity, green electricity, etc. into the air compression and energy storage and release unit, and compress the air energy storage to release electricity during the peak period of the power grid.

[0058] Specifically, all pipelines are made of carbon steel.

[0059] The second low-temperature hot water pipeline 130 connected between the low-temperature storage tank 12 and the liquid inlet of the gas-liquid heat exchanger 8 is a carbon steel pipeline; the first high-temperature hot water pipeline 100 connected between the liquid outlet of the gas-liquid heat exchanger 8 and the high-temperature storage tank 11 is a carbon steel pipeline; the second high-temperature hot water pipeline 110 connected between the high-temperature storage tank 11 and the liquid inlet of the gas-liquid reheater 10 is a carbon steel pipeline; the first low-temperature hot water pipeline 120 connected between the low-temperature storage tank 12 and the liquid outlet of the gas-liquid reheater 10 is a carbon steel pipeline; the first low-temperature compressed air pipeline 20 connected between the gas-liquid heat exchanger 8 and the gas inlet of the gas storage device 9 is a carbon steel pipeline; the second low-temperature compressed air pipeline 21 connected between the gas outlet of the gas storage device 9 and the gas inlet of the gas-liquid reheater 10 is a carbon steel pipeline; the second high-temperature compressed air pipeline 22 between the gas outlet of the gas-liquid reheater 10 and the expander 13 is a carbon steel pipeline.

[0060] Specifically, the gas storage device 9 is a plurality of pressure vessels, which are connected in parallel through pipelines, and are connected to the gas outlet of the gas-liquid heat exchanger 8 and the gas inlet of the gas-liquid reheater 10, wherein the plurality of pressure vessels are made of pressure-resistant materials.

[0061] Specifically, the electric furnace waste heat boiler 2 is connected to the electric furnace 1, and the electric furnace 1 is connected to the municipal power grid 3 to provide electric energy to the electric furnace during the peak hours of the municipal power grid 3.

[0062] Working principle:

[0063] The high-temperature flue gas generated by the electric furnace 1 is sent to the electric furnace waste heat boiler 2 through the electric furnace flue gas pipeline 200. The low-temperature saturated steam of 200°C produced by the electric furnace waste heat boiler 2 is sent to the high-temperature storage tank 11 through the electric furnace waste heat steam pipeline 140 to increase the temperature of the hot water in the high-temperature storage tank 11.

[0064] During the air compression period, the power consumption of the compressor 7 in the air compressor system is jointly supplied by the municipal power grid 3 and the photovoltaic power station 4. During the off-peak period of the power grid, it is mainly supplied by the municipal power grid 3; during the photovoltaic power generation period of the daytime, it is supplied by the photovoltaic power station 4. After the 200°C high-temperature air generated by the compressor 7 and the 50°C low-temperature hot water sent by the low-temperature storage tank 12 are heat exchanged in the gas-liquid heat exchanger 8, the air temperature is reduced to 30°C, and the generated cold air enters the gas storage device 9 for storage; the generated high-temperature hot water enters the high-temperature storage tank 11 for storage, realizing the storage of compression heat. During the expansion power generation period, the high-temperature hot water in the high-temperature storage tank 11 and the 30°C low-temperature air are heat exchanged in the gas-liquid reheater 10, and the produced 170°C high-temperature air enters the expander 13 to do work, and the produced 50°C low-temperature hot water is sent back to the low-temperature storage tank 12 for storage. The expander 13 and the generator 14 are connected by a coupling, and the generated power is incorporated into the factory power grid 5 for the power furnace 1 to produce and use.

[0065] The energy power system for improving the utilization rate of the electric furnace provided by the utility model saves secondary energy, realizes the continuous production of the electric furnace, and improves the utilization rate of the electric furnace.

[0066] The utility model provides a specific embodiment, in which an electric furnace smelting enterprise in a certain region is taken as an example for analysis, and its current situation is as follows:

[0067] (1) The peak, flat and off-peak hours in the region are all 8 hours per day, and the electricity prices are 1 yuan / kWh, 0.6 yuan / kWh and 0.3 yuan / kWh respectively;

[0068] (2) One electric furnace with a nominal capacity of 100 tons is equipped, the smelting cycle is 40 minutes, and the production system is implemented to avoid peak hours and go to valley hours. The electric furnace operates at 100% load during valley hours and normal hours, and stops production during peak hours. The average load rate is 66.7%, the annual effective production days are 330 days, and the annual steel output is 792,000 tons;

[0069] (3) The power consumption per ton of steel is 500 kWh / t, and the average power load of the electric furnace is 75 MW;

[0070] (4) The steam parameters of the waste heat boiler configured for the electric furnace are 2.45MPa(a) and 225℃. During the production period of the electric furnace, the steam production is 20t / h. Currently, due to the shutdown of the electric furnace during peak hours, the original steam turbine generator set cannot adapt to long-term rapid start and shutdown, and the steam is in a dissipated state.

[0071] Based on the above-mentioned current operating conditions, this energy power system to improve the utilization rate of electric furnaces is adopted, and a 75MW / 600MWh compressed air energy storage power station is configured. The energy storage system stores energy during valley hours and releases energy during peak hours to provide stable electricity for the peak hours of electric furnace smelting. At the same time, the waste heat generated by the electric furnace is added to the adiabatic compressed air energy storage system to increase the inlet air temperature of the expander, thereby improving the system's electric-electric conversion efficiency. After configuring this system, the implementation effects are as follows:

[0072] (1) The 20t / h low-pressure steam produced by the waste heat of the electric furnace is fully incorporated into the energy storage system, which can increase the power of the expander by 3MW and increase the system's electric-to-electric conversion efficiency from 70% to 73%, thereby improving energy utilization;

[0073] (2) The 105,600 tons of steam released annually by the original system is effectively recovered, which can help the company save 11,000 tons of standard coal per year and reduce carbon dioxide emissions by 27,500 tons per year.

[0074] (3) The energy storage system stores electricity during valley hours and releases electricity during peak hours. The fixed electricity cost of the energy storage system over its entire life cycle is about 0.15 yuan / kWh. Considering the valley hour charging cost of 0.41 yuan / kWh, the comprehensive power supply cost of this energy storage system is 0.56 yuan / kWh, which is 0.44 yuan / kWh lower than the peak hour electricity price of the power grid, and can effectively reduce the peak hour electricity cost of the electric furnace.

[0075] (4) Compared with the original production model, the electric furnace can achieve 24-hour low-cost continuous production, the load rate is increased to 100%, and the annual steel output is increased to 1.188 million tons. Assuming that under the original production system, the profit per ton of steel is 100 yuan / t, the annual profit of the steel plant can be increased from the original profit of 79.2 million yuan to 118 million yuan, and the profit margin is increased by 48%, which is a significant effect.

[0076] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An energy power system for improving the utilization rate of an electric furnace, characterized in that: include: An air compression unit connected to the municipal power grid (3) and used to compress air and output high-temperature air when the municipal power grid (3) is off-peak; The energy storage and release unit comprises a gas-liquid heat exchanger (8), a gas storage device (9), a gas-liquid reheater (10), a high-temperature storage tank (11) and a low-temperature storage tank (12), wherein: A gas-liquid heat exchanger (8) is used for heat exchange and energy storage between high-temperature air output by the air compression unit and a low-temperature liquid working medium, wherein the gas inlet is connected to the air compression unit via a pipeline, the gas outlet is connected to the gas storage device (9) via a pipeline, the liquid inlet is connected to the low-temperature storage tank (12) via a pipeline, and the liquid outlet is connected to the high-temperature storage tank (11) via a pipeline; The high-temperature storage tank (11) is also connected to the electric furnace waste heat boiler (2) through a steam pipeline, and the electric furnace waste heat boiler (2) is used to add intermittent waste heat to adjust the temperature of the high-temperature liquid working medium after heat exchange; A gas-liquid reheater (10) is used to perform heat exchange and energy release between low-temperature air in the gas storage device (9) and high-temperature liquid working fluid in the high-temperature storage tank (11), wherein the liquid inlet is connected to the high-temperature storage tank (11) via a pipeline, the liquid outlet is connected to the low-temperature storage tank (12) via a pipeline, and the gas inlet is connected to the gas storage device (9) via a pipeline; The power generation unit comprises an expander (13), wherein the expander (13) is connected to the gas outlet of the gas-liquid reheater (10), and the high-temperature air introduced from the gas-liquid reheater (10) performs work through the expander (13) to generate power.

2. The energy power system for improving the utilization rate of an electric furnace according to claim 1, characterized in that: The air compression unit is also connected to a photovoltaic power station (4), and the photovoltaic power station (4) is arranged in parallel with the municipal power grid (3) and connected to the air compression unit via a power grid line, and a dual power switching system is provided on the power grid line.

3. The energy power system for improving the utilization rate of an electric furnace according to claim 1, characterized in that: The factory electricity generated by the energy power system is incorporated into a factory power grid (5), and the factory power grid (5) is electrically connected to the electric furnace (1).

4. The energy power system for improving the utilization rate of an electric furnace according to claim 1, characterized in that: The air compression unit comprises a plurality of compressor motors (6) and a plurality of compressors (7), each compressor (7) corresponds to each compressor motor (6) one by one and is connected by a coupling; The power generation unit comprises an expander (13) and a generator (14); the generator (14) and the expander (13) are coaxially arranged and connected by a coupling; the compressor (7) and the gas-liquid heat exchanger (8) as well as the gas-liquid reheater (10) and the expander (13) are connected by pipelines.

5. The energy power system for improving the utilization rate of an electric furnace according to claim 4, characterized in that: The expander (13) is an air turbine, which is used to convert the heat energy and potential energy of the air fed into the expander into mechanical energy.

6. The energy power system for improving the utilization rate of an electric furnace according to claim 1, characterized in that: A pipeline pump and a control valve are provided on the pipeline connecting the low-temperature storage tank (12) and the liquid inlet of the gas-liquid heat exchanger (8), and on the pipeline connecting the liquid outlet of the gas-liquid heat exchanger (8) and the high-temperature storage tank (11).

7. The energy power system for improving the utilization rate of an electric furnace according to claim 1, characterized in that: All of the pipelines are equipped with control valves.

8. The energy power system for improving the utilization rate of an electric furnace according to claim 1, characterized in that: All pipelines mentioned are made of carbon steel.

9. The energy power system for improving the utilization rate of an electric furnace according to claim 1, characterized in that: The gas storage device (9) is a plurality of pressure vessels, which are connected in parallel via pipelines, and are connected to the gas outlet of the gas-liquid heat exchanger (8) and the gas inlet of the gas-liquid reheater (10).

10. The energy power system for improving the utilization rate of an electric furnace according to claim 3, characterized in that: The electric furnace (1) is also connected to the municipal power grid (3) to provide backup electricity for the electric furnace during peak hours of the municipal power grid (3).

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