Disclosure of Invention
The invention aims to provide an electric-thermal-electric energy storage system and a method, which can ensure the thermal power conversion efficiency and improve the safety of system operation.
In order to achieve the purpose, the invention adopts the following technical scheme:
an electro-thermal-electric energy storage system comprising:
the heat storage device is internally provided with a heat storage medium, the heat storage medium is silicon, the silicon is converted from a solid state into a liquid state during heat storage, and the silicon is converted from the liquid state into the solid state during heat release;
the first air compressor is used for compressing air to 0.15-0.3 MPa, and is connected with the inlet of the heat exchanger so as to facilitate heat exchange between the air and the liquid silicon;
the turbine device is connected with the outlet of the heat exchanger;
a generator coupled to the turbine unit.
Optionally, the electric-thermal-electric energy storage system further comprises a heat regenerator, the heat regenerator is connected with the first air compressor, the heat exchanger and the turbine device, and the heat regenerator is configured to exchange heat between air flowing out of the first air compressor and exhaust gas flowing out of the turbine device.
Optionally, the electric-thermal-electric energy storage system further comprises a compression device, the compression device is provided with an exhaust port, and the compression device is connected with the turbine device through the heat regenerator so as to compress the flowing exhaust gas to be not less than the atmospheric pressure and then discharge the compressed exhaust gas through the exhaust port.
Optionally, the compression device includes a second air compressor and a third air compressor, the second air compressor is connected to both the heat regenerator and the third air compressor, and the exhaust port is disposed on the third air compressor.
Optionally, the electric-thermal-electric energy storage system further comprises a cooling device connected to both the regenerator and the compression device.
Optionally, the cooling device includes a first spray cooling tower and a second spray cooling tower, the first spray cooling tower is connected to both the heat regenerator and the second air compressor, and the second spray cooling tower is connected to both the second air compressor and the third air compressor.
Optionally, the first spray cooling tower and the second spray cooling tower are both provided with a water inlet and a water outlet.
The invention also provides an energy storage method, which applies the electric-thermal-electric energy storage system, and the energy storage method comprises the following steps:
s1, in the heat storage stage, the heat storage device works, electric energy is input into the heat storage device, the electric energy is converted into heat energy to be stored in the high-temperature liquid silicon, and the temperature is above 1414 ℃;
s2, in an energy release stage, a first air compressor works, sucked air is compressed to 0.15-0.3 MPa and then is sent into a heat exchanger to exchange heat with high-temperature liquid silicon, the air absorbs heat, and meanwhile, the high-temperature liquid silicon is converted into a solid state;
and S3, the turbine device works, and high-temperature air enters the turbine device to expand and do work and push the generator to generate electricity.
Optionally, the step S2 specifically includes:
s21, in the energy release stage, starting the first air compressor, compressing the sucked air to 0.15-0.3 MPa, and then sending the compressed air into a heat regenerator to exchange heat with the exhaust gas flowing out of the turbine device;
and S22, conveying the air after heat exchange to the heat exchanger to exchange heat with the high-temperature liquid silicon, so that the air absorbs heat, and the high-temperature liquid silicon is converted into a solid state.
Optionally, after the step S3, the method further includes: and S4, discharging the exhaust gas flowing out of the turbine device into a heat regenerator for heat exchange and cooling, sequentially cooling the exhaust gas after heat exchange in a first spray cooling tower, pressurizing in a second air compressor, cooling in the second spray cooling tower, and finally pressurizing in a third air compressor to be not less than the atmospheric pressure and then discharging into the atmosphere.
The invention has the beneficial effects that:
1. silicon is selected as a heat storage medium, the melting point of the silicon is 1414 ℃, and a high enough initial temperature can be provided for thermal power conversion, so that the heat efficiency is improved;
2. the first air compressor is arranged to compress the inlet air to 0.15-0.3 MPa, which is lower than the compression pressure of the existing air working medium thermal cycle system, so that the working pressure of the air working medium is reduced, the heat exchanger and the turbine device are prevented from bearing excessive pressure, and the operation safety of the system is improved; meanwhile, the reduction of the heat efficiency caused by the reduction of the air pressure can be compensated by the increase of the energy storage temperature of the silicon medium, so that the heat power conversion efficiency can be ensured, and the safety of the system operation can be improved.
Detailed Description
In order to make the technical problems solved, technical solutions adopted and technical effects achieved by the present invention clearer, the technical solutions of the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the description of the present invention, unless expressly stated or limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, e.g., as meaning permanently connected, removably connected, or integral to one another; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.
The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings.
The embodiment of the invention discloses an electricity-heat-electricity energy storage system, which comprises a heat storage device 1, a first air compressor 2, a turbine device 3 and a generator 4, wherein the heat storage device 1 is connected with the first air compressor 2 and the turbine device 3, and the turbine device 3 is connected with the generator 4, as shown in figure 1. Illustratively, a heat storage medium is contained in the heat storage device 1, the heat storage medium is silicon, silicon is converted from a solid state to a liquid state during heat storage, and is converted from the liquid state to the solid state during heat release, and a heat exchanger 11 is further arranged in the heat storage device 1. The first air compressor 2 is used for compressing air to 0.15-0.3 MPa, and the first air compressor 2 is connected with an inlet of the heat exchanger 11 so as to facilitate heat exchange between the air and the liquid silicon. The turbine unit 3 is connected to the outlet of the heat exchanger 11. The generator 4 is connected to the turbine unit 3.
According to the invention, silicon is selected as a heat storage medium, the melting point of the silicon is 1414 ℃, and a high enough initial temperature can be provided for thermal power conversion, so that the heat efficiency is improved;
the first air compressor 2 is further arranged to compress the inlet air to 0.15-0.3 MPa, which is lower than the compression pressure of the existing air working medium thermal circulation system, so that the working pressure of the air working medium is reduced, the heat exchanger 11 and the turbine device 3 are prevented from bearing excessive pressure, and the operation safety of the system is improved; meanwhile, the reduction of the heat efficiency caused by the reduction of the air pressure can be compensated by the increase of the energy storage temperature of the silicon medium, so that the heat power conversion efficiency can be ensured, and the safety of the system operation can be improved.
Optionally, the heat storage device 1 can be in communication with an electrical apparatus to energize to convert electrical energy into thermal energy for storage in the liquid silicon. Since the melting point of silicon is 1414 ℃, a sufficiently high initial temperature can be provided for thermodynamic conversion. The capacity of the heat storage device 1 can be set according to the heat storage requirement and the occupied space, and the embodiment is not particularly limited.
In the present embodiment, the heat exchanger 11 is used for exchanging heat between air and liquid silicon to realize heat energy conversion. In the embodiment, the temperature of the air after heat exchange can reach 1000-1350 ℃, and the heat conversion efficiency is greatly improved. Since the heat exchanger 11 is prior art, it will not be described in detail herein.
In this embodiment, the first air compressor 2 is used for pressurizing the incoming air to increase the initial pressure of the air in preparation for the subsequent heat conversion.
The turbine device 3 is a machine that converts energy contained in a fluid medium into mechanical work, and in the present embodiment, converts thermal energy contained in air into mechanical energy.
The generator 4 is in transmission connection with the turbine device 3 and can convert mechanical energy into electric energy. Since the specific structures and principles of the first air compressor 2, the turbine unit 3 and the generator 4 are well known in the art, they are not described in detail herein.
In order to improve the heat energy utilization rate and reduce the heat loss, the electric-heat-electric energy storage system further comprises a heat regenerator 5, the heat regenerator 5 is connected with the first air compressor 2, the heat exchanger 11 and the turbine device 3, the heat regenerator 5 is configured to exchange heat between air flowing out of the first air compressor 2 and exhaust gas flowing out of the turbine device 3, the exhaust waste heat is used for preheating the entering air, the heat recovery is realized, and the energy utilization rate is improved. Further, since the exhaust pressure flowing out after passing through the turbine unit 3 is less than the atmospheric pressure, which is about 0.05MPa, in order to ensure smooth exhaust, the above-mentioned electric-thermal-electric energy storage system further includes a compression unit 6, the compression unit 6 is provided with an exhaust port 621, the compression unit 6 is connected with the turbine unit 3 through a heat regenerator 5, so as to compress the flowing-out exhaust to be not less than the atmospheric pressure and then discharge the exhaust through the exhaust port 621.
The compression device 6 includes a second air compressor 61 and a third air compressor 62, the second air compressor 61 and the heat regenerator 5 are connected to the third air compressor 62, and an air outlet 621 is provided on the third air compressor 62. The air flowing out is compressed to not less than the atmospheric pressure by the continuous pressurization of the second air compressor 61 and the third air compressor 62, and is finally smoothly discharged through the air outlet 621. In this embodiment, in order to reduce the energy consumption of the air compressor, it is preferable to compress the air to atmospheric pressure. In other embodiments, the number of the air compressors may be three, four or more as required, and the exhaust air may be compressed to be greater than the atmospheric pressure, which is not limited to this embodiment.
In order to further reduce the electric energy consumption of the compression device 6, the electric-thermal-electric energy storage system further comprises a cooling device 7, wherein the cooling device 7 is connected with both the heat regenerator 5 and the compression device 6 so as to cool the exhaust gas flowing out of the heat regenerator 5, and the cooled exhaust gas flows into the compression device 6 again for pressurization.
The cooling device 7 comprises a first spray cooling tower 71 and a second spray cooling tower 72, wherein the first spray cooling tower 71 is connected with the heat regenerator 5 and the second air compressor 61, and the second spray cooling tower 72 is connected with the second air compressor 61 and the third air compressor 62. So as to cool the outflowing exhaust gas and reduce the energy consumption of the second air compressor 61 and the third air compressor 62.
The first spray cooling tower 71 and the second spray cooling tower 72 are both provided with a water inlet and a water outlet, cooling water enters the cooling tower through the water inlet to spray, cool and cool the exhaust gas, and the cooled water is discharged from the water outlet so as to continuously cool the exhaust gas.
Further, the electric-thermal-electric energy storage system further comprises a fixed shaft 8, and the first air compressor 2, the second air compressor 61, the third air compressor 62, the turbine device 3 and the generator 4 are all fixed through the fixed shaft 8, so that the compactness of the whole energy storage system is improved.
The embodiment of the invention also provides an energy storage method, which applies the electric-thermal-electric energy storage system, and comprises the following steps:
s1, in the heat storage stage, the heat storage device 1 works, electric energy is input into the heat storage device 1, the electric energy is converted into heat energy to be stored in high-temperature liquid silicon, and the temperature is 1430 ℃;
s2, in the energy release stage, the first air compressor 2 works, sucked air is compressed to 0.15-0.3 MPa and then is sent into the heat exchanger 11 to exchange heat with high-temperature liquid silicon, the air absorbs heat, and meanwhile, the high-temperature liquid silicon is converted into a solid state;
and S3, the turbine device 3 works, and high-temperature air enters the turbine device 3 to expand and do work and push the generator 4 to generate electricity.
By selecting silicon as a heat storage medium, the melting point of the silicon is 1414 ℃, and a high enough initial temperature can be provided for thermal power conversion, so that the thermal efficiency is improved, the first air compressor 2 is further arranged to compress the inlet air to 0.15-0.3 MPa, which is lower than the compression pressure of the existing air working medium thermal power circulation system, so that the working pressure of the air working medium is reduced, the heat exchanger 11 and the turbine device 3 are prevented from bearing excessive pressure, the operation safety of the system is improved, and meanwhile, the reduction of the thermal efficiency caused by the reduction of the air pressure can be compensated by the improvement of the energy storage temperature of the silicon medium, so that the thermal power conversion efficiency can be ensured, and the operation safety of the system can be improved.
Optionally, step S2 specifically includes:
s21, in the energy release stage, starting the first air compressor 2, compressing the sucked air to 0.15-0.3 MPa, and then sending the compressed air into the heat regenerator 5 to exchange heat with the exhaust gas flowing out of the turbine device 3;
and S22, conveying the air subjected to heat exchange to the heat exchanger 11 to exchange heat with the high-temperature liquid silicon, so that the air absorbs heat, and the high-temperature liquid silicon is converted into a solid state.
In this embodiment, the first air compressor 2 compresses the sucked air to 0.25MPa, and the temperature of the air after heat absorption is 1000 ℃ to 1350 ℃, for example, 1250 ℃, thereby greatly improving the heat conversion efficiency. In other embodiments, the air may be compressed to 0.15MPa or 0.3MPa, but the present embodiment is not limited thereto.
Further, after step S3, the method further includes: and S4, discharging the exhaust gas flowing out of the turbine device 3 into a heat regenerator 5 for heat exchange and temperature reduction, so as to preheat the entering air by using the exhaust waste heat, realize heat recovery and improve the energy utilization rate. The exhaust gas after heat exchange sequentially enters a first spray cooling tower 71 for cooling, then enters a second air compressor 61 for pressurization, then enters a second spray cooling tower 72 for cooling, and finally enters a third air compressor 62 for pressurization till the pressure is not less than the atmospheric pressure and then is discharged into the atmosphere.
The exhaust gas after reaction is pressurized to be not less than the atmospheric pressure value through the second air compressor 61 and the third air compressor 62 so as to be discharged smoothly; and meanwhile, a first spray cooling tower 71 and a second spray cooling tower 72 are arranged to cool the exhaust gas so as to reduce the energy consumption of the air compressor. In order to reduce the energy consumption of the air compressor, it is preferable to compress the exhaust gas to atmospheric pressure in this embodiment. In other embodiments, the number of the air compressors and the spray towers may be three, four or more according to the requirement, and the exhaust gas may be compressed to be greater than the atmospheric pressure, which is not limited in this embodiment.
In summary, embodiments of the present invention provide an electrical-thermal-electrical energy storage system and method, wherein silicon is used as a heat storage medium, and a melting point of silicon is 1414 ℃, so as to provide a high enough initial temperature for thermal power conversion, thereby improving thermal efficiency;
the first air compressor 2 is further arranged to compress the inlet air to 0.15-0.3 MPa, which is lower than the compression pressure of the existing air working medium thermal circulation system, so that the working pressure of the air working medium is reduced, the heat exchanger 11 and the turbine device 3 are prevented from bearing excessive pressure, and the operation safety of the system is improved; meanwhile, the reduction of the heat efficiency caused by the reduction of the air pressure can be compensated by the increase of the energy storage temperature of the silicon medium, so that the heat power conversion efficiency can be ensured, and the safety of the system operation can be improved.
It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.