Air medium isothermal adiabatic circulation energy storage power generation system

Abstract

An air medium isothermal adiabatic circulating energy storage power generation system comprises an isothermal adiabatic compression system, an isothermal adiabatic expansion system, an air storage system, a low-temperature energy storage tank, a high-temperature energy storage tank, an energy storage medium circulating pump, a heat exchanger, a control device, a circulating working medium, an energy storage medium and connecting pipelines between the circulating working medium and the energy storage medium. The air storage system comprises a compressed air storage tank, a hydraulic generator, a pressure pump and a water tank; the hydraulic generator and the pressure pump are connected in parallel between the bottom of the compressed air storage tank and the bottom end of the water tank; the design aims at achieving integration of energy storage and power generation through the multi-stage compression and expansion process in combination with the energy storage technology.

Description

Technical Field

[0001] The utility model belongs to the technical field of energy storage, and particularly relates to an air-medium isothermal and adiabatic cycle energy storage power generation system. Background Technique

[0002] Under the background of the global energy structure transformation towards clean and renewable energy, the importance of energy storage + backup systems has become increasingly prominent. With the large-scale deployment of renewable energy such as photovoltaic and wind power, their inherent instability and uncertainty problems have become increasingly prominent. These problems not only affect the continuity and stability of energy supply, but also pose challenges to the safe operation of the power grid.

[0003] As a key means to solve this problem, the importance of energy storage + backup systems is self-evident. First of all, the energy storage system can effectively store the excess and unstable energy generated by renewable energy and release it when needed, so as to balance energy supply and demand and improve energy utilization efficiency. Secondly, the backup energy system can provide stable energy support when the supply of renewable energy is insufficient or interrupted, ensuring the continuity of energy supply. This combined strategy can not only effectively address the instability and uncertainty problems of renewable energy, but also provide strong support for the transformation of the energy structure. Summary of the Invention

[0004] The utility model provides an air-medium isothermal and adiabatic cycle energy storage power generation system, which combines isothermal compression, isothermal expansion technology and isobaric gas storage technology, and organically combines the energy storage system and the backup energy system to form a new energy supply mode. This mode can not only address the instability and uncertainty problems of renewable energy, but also flexibly adjust the energy supply strategy according to actual needs to achieve efficient utilization and optimal allocation of energy.

[0005] Specifically described as follows: An air-medium isothermal and adiabatic cycle energy storage power generation system includes an isothermal and adiabatic compression system, an isothermal and adiabatic expansion system, a gas storage system, a low-temperature energy storage tank, a high-temperature energy storage tank, an energy storage medium circulation pump, a heat exchanger, a control device, a circulating working fluid, an energy storage medium, and the connecting pipelines between them;

[0006] The gas storage system includes a compressed air storage tank, a hydraulic generator, a pressure pump, and a water tank; the hydraulic generator and the pressure pump are connected in parallel between the bottom of the compressed air storage tank and the bottom end of the water tank;

[0007] The working fluid inlet of the isothermal and adiabatic compression system is directly connected to the atmosphere, the working fluid outlet of the isothermal and adiabatic compression system is communicated with the working fluid inlet of the isothermal and adiabatic expansion system, and both are communicated with one end of the working fluid medium channel of the heat exchanger; the other end of the working fluid medium channel of the heat exchanger is communicated with the compressed air storage tank of the gas storage system;

[0008] The low-temperature energy storage tank is installed at one end of the energy storage medium channel of the heat exchanger, and the other end of the energy storage medium channel of the heat exchanger is communicated with the high-temperature energy storage tank;

[0009] The energy storage medium circulation pump is installed between the low-temperature energy storage tank and the high-temperature energy storage tank.

[0010] Further, the isothermal adiabatic compression system includes an isothermal compressor, a cooler, an adiabatic compressor, and the compressed working fluid pipelines between them;

[0011] The isothermal compressor is a multi-stage isothermal compressor;

[0012] The adiabatic compressor is a multi-stage adiabatic compressor;

[0013] The isothermal compressor and the adiabatic compressor are coaxially connected in series;

[0014] The cooler is installed on the compressed working fluid pipeline between every two stages of the isothermal compressor. The inlet / outlet of the air medium channel of the cooler is respectively connected to the working fluid outlet of the previous-stage isothermal compressor / the working fluid inlet of the next-stage isothermal compressor; The compression mechanisms of every two stages of the adiabatic compressor are directly communicated through the compressed working fluid pipeline, that is, the working fluid outlet of the previous-stage adiabatic compressor and the working fluid inlet of the next-stage adiabatic compressor are connected through the compressed working fluid pipeline.

[0015] Further, the isothermal adiabatic expansion system includes an isothermal expander, a combustion chamber, an adiabatic expander, and the compressed working fluid pipelines;

[0016] The isothermal expander is a multi-stage isothermal expander;

[0017] The adiabatic expander is a multi-stage adiabatic expander;

[0018] The isothermal expander and the adiabatic expander are coaxially connected in series; The outlet of the last-stage isothermal expander is connected to the inlet of the first-stage adiabatic expander through the compressed working fluid pipeline;

[0019] The combustion chamber is installed on the expansion working fluid pipeline between every two stages of the isothermal expander or on the working fluid pipeline between the heat exchanger and the first-stage expander

[0020] The expansion mechanisms of every two stages of the adiabatic expander are communicated through the compressed working fluid pipeline, that is, the working fluid outlet of the previous-stage adiabatic expander and the working fluid inlet of the next-stage adiabatic expander are connected through the compressed working fluid pipeline, and the working fluid outlet of the last-stage adiabatic expander is directly connected to the atmosphere, directly discharging the compressed air tail gas after doing work into the environment.

[0021] Further, the isothermal compressor and the adiabatic compressor are of centrifugal or axial-flow type and are composed of a multi-stage isothermal compressor and a multi-stage adiabatic compressor connected in series.

[0022] Further, both the isothermal expander and the adiabatic expander are of the turbine type and are composed of a series connection of a multi-stage isothermal expander and an adiabatic expander.

[0023] Further, the cooler is one of a water-cooled cooler or an air-cooled cooler.

[0024] Further, the gas storage system includes a compressed air storage tank, a water column, and a water tank; the water column is connected between the bottom end of the compressed air storage tank and the bottom end of the water tank, and the water tank is located above the compressed air storage tank, forming a communicating vessel with the compressed air storage tank below and the water tank above, and relying on the gravity of water to maintain the equal pressure of the compressed air in the compressed air storage tank.

[0025] Further, the gas storage system includes a compressed air storage tank, and the compressed air storage tank is a sac-shaped gas storage bag; the sac-shaped gas storage bag is located in deep water at a specific pressure.

[0026] Further, the fuel in the combustion chamber is coal gas, natural gas, hydrogen, or liquid fuel.

[0027] Further, the control device of the power generation system is a DCS control system. The control device collects the working parameters of each component of the power generation system equipment, including but not limited to temperature, pressure, flow rate, stress, displacement, vibration, position, current, voltage, resistance, frequency, and power, and controls and protects the operation of each component according to the relevant parameters and control objectives.

[0028] As described above, the power generation system equipment designed by the present utility model significantly improves the system thermal efficiency through a carefully designed multi-stage isothermal compression and expansion system. During the compression process, the isothermal compressor is divided into multiple stages, and after each stage of compression, the cooler is used to quickly reduce the temperature of the working medium to limit the amplitude of temperature rise, achieving approximate "isothermal compression". During the expansion process, we adopt a method of multi-stage expansion accompanied by multi-stage heating to ensure that the working medium can maintain a high temperature and average temperature during expansion. This unique design makes the entire thermodynamic process closer to the ideal "Carnot cycle", thereby greatly improving the thermal efficiency of the system.

[0029] In order to address the instability and uncertainty issues of renewable energy, the present utility model introduces a combined strategy of an energy storage + backup system. The energy storage system can effectively store the excess and unstable energy generated by renewable energy and release it when needed, balance the energy supply and demand, improve the energy utilization efficiency, and enable the system to operate continuously and stably without being restricted by the power generation and power consumption. The backup energy system can provide stable energy support when the supply of renewable energy is insufficient or interrupted, ensuring the continuity of energy supply.

[0030] The generator with energy storage of the present utility model plays a crucial role in the operation of the power grid. It can perform excellently in aspects such as peak shaving and valley filling of the power grid, smoothing the load, and quickly adjusting the power grid frequency, which helps to improve the overall operation efficiency of the power grid. In addition, since the equipment of the power generation system of the present utility model directly uses air as the working medium and adopts an open-cycle design, even if there is leakage during the working process, the impact on the system efficiency is relatively small. This not only reduces the requirements for the manufacturing and assembly precision of components, but also helps to reduce the construction cost and the later maintenance cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0032] Attached Figure 1 is a schematic diagram of the structure and principle of the energy storage power generation system of the present utility model.

[0033] Attached Figure 2 is Embodiment 1 of the energy storage power generation system of the present utility model.

[0034] Attached Figure 3 is Embodiment 2 of the energy storage power generation system of the present utility model.

[0035] Attached Figure 4 is Embodiment 3 of the energy storage power generation system of the present utility model.

[0036] The meanings represented by the serial numbers in the above figures are as follows: 1 isothermal compressor; 11 primary isothermal compressor; 12 secondary isothermal compressor; 13 intermediate-stage isothermal compressor; 14 final-stage isothermal compressor; 2 cooler; 21 primary cooler; 22 secondary cooler; 23 intermediate-stage cooler; 24 final-stage cooler; 3 adiabatic compressor; 31 primary adiabatic compressor; 32 secondary adiabatic compressor; 33 intermediate-stage adiabatic compressor; 34 final-stage adiabatic compressor; 4 isothermal expander; 41 primary isothermal expander; 42 final-stage isothermal expander; 5 combustion chamber; 51 primary combustion chamber; 52 final-stage combustion chamber; 6 adiabatic expander; 61-66 multi-stage adiabatic expanders; 7 heat exchanger; 81 main inlet pipe for cooling medium; 82 main outlet pipe for cooling medium; 9 control device; 10 compressed air storage tank; 101 water column; 102 water tank; 103 water surface in the gas storage device; 104 water surface of the water tank; 105 horizontal plane; 111 first valve; 112 second valve; 113 third valve, 114 fourth valve, 115 fifth valve; 116 sixth valve; 117 seventh valve, 118 eighth valve; 121 low-temperature energy storage tank; 122 high-temperature energy storage tank; 131 energy storage medium circulation pump; 140 pressure pump; 150 hydraulic generator. Detailed implementation manners

[0037] To make the objectives, technical solutions and advantages of the present utility model clearer, the technical solutions of the present utility model will be described in detail below.

[0038] Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments.

[0039] All other implementation manners obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts fall within the scope protected by the present utility model. To make the embodiments easier to understand, multiple embodiments or implementation methods are provided below to illustrate the related devices, modules, and functions of the present utility model.

[0040] To enable the readers of this embodiment to quickly understand the implementation manner of the present utility model, the working principle expressed in the attached Figure 1 will be described first. Detailed implementation manner one

[0042] As shown in the attached Figure 1As shown in the figure, an air-medium isothermal and adiabatic cycle energy storage power generation system includes: an isothermal and adiabatic compression system, an isothermal and adiabatic expansion system, a gas storage system, a low-temperature energy storage tank 121, a high-temperature energy storage tank 122, an energy storage medium circulation pump 131, a heat exchanger 7, a control device 9, a circulating working fluid, an energy storage medium, and the connecting pipelines between them. The working fluid inlet of the isothermal and adiabatic compression system is directly connected to the atmosphere. The working fluid outlet of the isothermal and adiabatic compression system is connected to the working fluid inlet of the isothermal and adiabatic expansion system, and both are connected to one end of the working fluid medium channel of the heat exchanger 7. The other end of the working fluid medium channel of the heat exchanger 7 is connected to the gas storage system. The low-temperature energy storage tank 121 and the high-temperature energy storage tank 122 are respectively installed at both ends of the energy storage medium channel of the heat exchanger 7. The energy storage medium circulation pump 131 is installed between the low-temperature energy storage tank 121 and the high-temperature energy storage tank 122.

[0043] As Figure 2 shown, the gas storage system includes a compressed air storage tank 10, a water column 101, and a water tank 102. The water column 101 is connected between the bottom end of the compressed air storage tank 10 and the bottom end of the water tank 102. The water tank 102 is located above the compressed air storage tank 10, thus forming a communicating vessel with the compressed air storage tank 10 at the bottom and the water tank 102 at the top, and relying on the gravity of water to maintain the isobaric pressure of the compressed air in the compressed air storage tank 10. There is a height difference h between the water surface 103 in the compressed air storage tank and the water surface 104 in the water tank. The pressure in the compressed air storage tank 10 is determined by the height difference h. Since h is relatively large, the pressure in the compressed air storage tank 10 is approximately equal everywhere, and it is approximately an isobaric compressed air storage tank.

[0044] Combined with Figure 1 and Figure 2 shown:

[0045] The isothermal and adiabatic compression system includes an isothermal compressor 1, a cooler 2, an adiabatic compressor 3, and the compressed working fluid pipelines between them. The isothermal compressor 1 is a multi-stage isothermal compressor. The adiabatic compressor 3 is a multi-stage adiabatic compressor. The isothermal compressor 1 and the adiabatic compressor 3 are coaxially connected in series. The cooler 2 is installed on the compressed working fluid pipeline between every two stages of the isothermal compressor. The inlet / outlet of the air medium channel of the cooler 2 is respectively connected to the working fluid outlet of the previous stage of the isothermal compressor / the working fluid inlet of the next stage of the isothermal compressor. The working fluid inlet of the first-stage isothermal compressor 11 is directly connected to the atmosphere. The outlet of the last-stage isothermal compressor 14 is connected to the working fluid inlet of the first-stage adiabatic compressor 31. The compression mechanisms of every two stages of the adiabatic compressor 3 are connected through the compressed working fluid pipeline, that is, the working fluid outlet of the previous stage of the adiabatic compressor and the working fluid inlet of the next stage of the adiabatic compressor are connected through the compressed working fluid pipeline.

[0046] The isothermal and adiabatic expansion system includes an isothermal expander 4, a combustion chamber 5, an adiabatic expander 6, and a compressed working fluid pipeline; the isothermal expander 4 is a multi-stage isothermal expander; the adiabatic expander 6 is a multi-stage adiabatic expander; the isothermal expander 4 and the adiabatic expander 6 are coaxially connected in series; the combustion chamber 5 is installed on the expansion working fluid pipeline between every two stages of the isothermal expander or on the working fluid pipeline between the heat exchanger 7 and the first-stage expansion mechanism, that is, the first-stage combustion chamber 51 is installed on the working fluid pipeline between the working fluid channel of the heat exchanger 7 and the first-stage expander 41, and the last-stage combustion chamber 52 is installed on the working fluid pipeline between the first-stage isothermal expander 41 and the last-stage isothermal expander 42; the working fluid outlet of the last-stage isothermal expander 42 is communicated with the inlet of the adiabatic expander 6; the working fluid outlets and inlets of every two stages of the adiabatic expander 6 are communicated through the compressed working fluid pipeline, that is, the working fluid outlet of the previous-stage adiabatic expander and the working fluid inlet of the next-stage adiabatic expander are connected through the compressed working fluid pipeline, and the working fluid outlet of the last-stage adiabatic expander 66 is directly connected to the atmosphere, and the compressed air tail gas after doing work is directly discharged into the air.

[0047] The heat exchanger 7 is a countercurrent heat exchanger. One end of the working fluid medium channel of the heat exchanger 7 is communicated with the outlet of the last-stage adiabatic compressor 34 and the inlet of the first-stage combustion chamber 51, and the other end is communicated with the compressed air storage tank 10 of the gas storage system.

[0048] One end of the energy storage medium channel of the heat exchanger 7 is communicated with the high-temperature energy storage tank 122, and the other end is respectively communicated with the outlet / import of the energy storage medium circulation pump 131 through the valve 116 / valve 117; the outlet / import of the energy storage medium circulation pump 131 is respectively communicated with the low-temperature energy storage tank 121 through the valve 118 / valve 115.

[0049] The cooler 2 is a water-cooled cooler, and the inlet / outlet of the cooling medium channel of the cooler 2 is respectively connected to the outlet / import of the cold water source; if the cooler 2 is an air-cooled cooler, the inlet / outlet of the cooling medium channel of the cooler 2 is communicated with the atmosphere.

[0050] The energy storage medium is one of molten salt liquid, phase change fluid (liquid and gas), water vapor, carbon dioxide, etc.

[0051] The circulating working fluid is air.

[0052] The function of the isothermal compressor 1 is to inhale the working medium air, perform multi-stage isothermal compression on the working medium air to boost the pressure of the working medium; the function of the cooler 2 is to dissipate the heat generated by the isothermal compressor 1 to the outside; the function of the adiabatic compressor 3 is to perform adiabatic compression on the isothermal-compressed working medium air; the function of the heat exchanger 7 is to perform heat exchange between the high-temperature and high-pressure air compressed by the adiabatic compressor 3 and the energy storage medium, store the heat in the high-temperature energy storage tank 122, and the function of the compressed air storage tank 10 is to store / release the compressed air medium cooled by heat exchange in the heat exchanger 7; the combustion chamber 5 is injected with fuel and mixed with the circulating working medium air entering the combustion chamber and then burns fully to generate tail gas. The isothermal expander 4 is connected to the combustion chamber and is driven by the tail gas generated by the combustion chamber 5 to generate power; the adiabatic expander 5 is connected to the last-stage isothermal expander of the isothermal expander 4 and is used to receive the tail gas discharged from the last-stage isothermal expander and expand step by step under a completely adiabatic state to generate power and tail gas with an approximate ambient temperature.

[0053] There are three working cycle processes in the power generation system of the present utility model, namely, the energy storage working cycle, the energy storage power generation working cycle, and the standby energy system cycle process.

[0054] When renewable energy (such as solar energy, wind energy) is abundant or electricity consumption at night decreases, the surplus power drives the compressor to work, compress and store the air, and achieve an efficient conversion of mechanical energy into the potential energy of compressed air. Please refer to Figure 2 As shown, the working cycle process of energy storage is as follows: Valves 112 / Valve 113 / Valve 115 / Valve 116 / Valve 114 are opened, and Valves 111 / Valve 117 / Valve 118 are closed. In this process, the isothermal compressor 1 inhales the working medium air from the atmosphere, and the isothermal compressor 1 compresses the working medium, and the temperature of the working medium rises; to avoid the working medium temperature rising too much, the cooler 2 is used to lower the temperature of the working medium, and the heat in the working medium is finally dissipated into the atmosphere; the isothermal compressor 1 is composed of multi-stage isothermal compression mechanisms, and through multi-stage compression, the pressure of the working medium is gradually increased until the required operating pressure is reached. After the isothermal compression is completed, the circulating working medium enters multi-stage adiabatic compression, that is, the working medium cooled out of the last-stage cooler 24 directly enters the adiabatic compressor 3, and successively undergoes high-pressure adiabatic compression by the first-stage adiabatic compressor 31, the second-stage adiabatic compressor 32, the intermediate-stage adiabatic compressor 33, and the last-stage adiabatic compressor 34, so that the circulating working medium reaches a high-temperature and high-pressure state; then the high-temperature and high-pressure circulating working medium enters the circulating working medium channel of the heat exchanger 7. At the same time, driven by the energy storage medium circulation pump 131, the low-temperature energy storage medium in the low-temperature energy storage tank 121 enters the energy storage medium channel of the heat exchanger 7 to absorb the heat of the high-temperature and high-pressure circulating working medium, becomes a high-temperature energy storage medium, and is stored in the high-temperature energy storage tank 122. The cooled high-temperature and high-pressure circulating medium enters the compressed air storage tank 10. At the same time, the water in the compressed air storage tank 10 is pressed outwards under the action of the high-pressure gas, enters the water tank 102 through the water column 114, and completes the energy storage process.

[0055] During peak electricity demand or when the supply of renewable energy is insufficient, the compressed air in the compressed air storage tank 10 is released through a pipeline and fully mixed with fuel in the combustion chamber 5 for combustion, providing sufficient energy for the subsequent power generation process and stable and efficient power support. As Figure 2 shown, the working cycle process of energy storage power generation: Valves 111 / Valve 113 / Valve 117 / Valve 118 / Valve 114 are opened, and Valves 112 / Valve 115 / Valve 116 are closed. During this process, since the compressed air storage tank 10 is connected to the water tank 102 through the water column 101, the pressure of the gas in the compressed air storage tank 10 during the energy storage process is converted into the gravity of the water column. The volume of the water tank 102 is very large, and the water level remains basically unchanged. That is, during the energy release process, the height difference between the pressure-bearing water surface and the water surface 104 of the water tank remains basically unchanged, the height of the liquid column remains unchanged, and the inside of the compressed air storage tank 10 is an isobaric environment. The expander operates under a constant working condition. The high-pressure air in the compressed air storage tank 10 enters the circulating working medium channel of the heat exchanger 7 under the action of the gravity of the water column. At the same time, driven by the energy storage medium circulation pump 131, the high-temperature energy storage medium in the high-temperature energy storage tank 122 enters the energy storage medium channel of the heat exchanger 7 to exchange heat with the low-temperature and high-pressure circulating working medium. The energy storage medium releases heat and cools down and is then stored in the low-temperature energy storage tank 122. The circulating medium absorbs heat and becomes a high-temperature and high-pressure circulating medium for isothermal and adiabatic expansion. In order to achieve approximate isothermal expansion, before the high-temperature and high-pressure working medium after heat absorption enters the isothermal expander 4, it first enters the combustion chamber 5 to be fully mixed with fuel for combustion and generate tail gas. The tail gas drives the isothermal expander 4 to do work. That is, the circulating working medium enters the primary combustion chamber 51, and at the same time, the primary combustion chamber 51 is injected with fuel and fully mixed with the working medium air entering the combustion chamber for combustion, generating primary tail gas; the primary isothermal expander 41 is connected to the primary combustion chamber 51, and the primary isothermal expander 41 is driven by the entering primary tail gas and generates power and the primary tail gas that cools down and reduces pressure after doing work; the primary tail gas that cools down and reduces pressure discharged from the primary isothermal expander 41 enters the secondary combustion chamber 52, is fully mixed with the injected fuel again for combustion, generating secondary tail gas. Subsequently, the secondary tail gas enters the secondary isothermal expander 42, and the secondary isothermal expander 42 is driven and generates power and the secondary tail gas that cools down and reduces pressure after doing work; the secondary tail gas that cools down and reduces pressure discharged from the secondary isothermal expander 42 enters the adiabatic expander 6, and the discharged tail gas expands step by step in a completely adiabatic state to generate power and the tail gas close to the ambient temperature discharged from the secondary adiabatic expander 66.

[0056] In the emergency of power shortage, if there is neither solar energy supply nor sufficient stored energy available, the power system will directly activate the backup energy cycle system. The cycle process of the backup energy system: Valves 111 and 112 are opened, and other valves are closed. In this process, the isothermal compressor 1 sucks in the working medium air from the atmosphere, and the isothermal compressor 1 compresses the working medium, and the temperature of the working medium rises; to avoid the working medium temperature rising too much, the cooler 2 is used to lower the temperature of the working medium, and the heat in the working medium is finally dissipated into the atmosphere; the isothermal compressor 1 consists of multiple-stage isothermal compression mechanisms. Through multi-stage compression, the pressure of the working medium is gradually increased until the required operating pressure is reached. After the isothermal compression is completed, the circulating working medium enters multi-stage adiabatic compression, that is, the working medium cooled out from the last-stage cooler 24 directly enters the adiabatic compressor 3, and successively undergoes high-pressure adiabatic compression by the first-stage adiabatic compressor 31, the second-stage adiabatic compressor 32, the intermediate-stage adiabatic compressor 33 and the last-stage adiabatic compressor 34, so that the circulating working medium reaches a high-temperature and high-pressure state; then the high-temperature and high-pressure circulating working medium enters the first-stage combustion chamber 51, and at the same time, the first-stage combustion chamber 51 is injected with fuel and mixed with the working medium air entering the combustion chamber and burns fully, generating primary exhaust gas; the first-stage isothermal expander 41 is connected to the first-stage combustion chamber 51, and the first-stage isothermal expander 41 is driven by the entering primary exhaust gas and generates power and the primary exhaust gas that is cooled and depressurized after doing work; the cooled and depressurized primary exhaust gas discharged from the first-stage isothermal expander 41 enters the last-stage combustion chamber 52, is mixed with the injected fuel and burns fully again, generating secondary exhaust gas, and then the secondary exhaust gas enters the last-stage isothermal expander 42, and the last-stage isothermal expander 42 is driven and generates power and the secondary exhaust gas that is cooled and depressurized after doing work; the cooled and depressurized secondary exhaust gas discharged from the last-stage isothermal expander 42 enters the multi-stage adiabatic expander 6, and the discharged exhaust gas expands step by step in a completely adiabatic state to generate power and the exhaust gas close to the ambient temperature discharged from the last-stage adiabatic expander 66, thus completing the cycle process of the backup energy system.

[0057] The main purpose of adopting multi-stage compression above is: to avoid the temperature rising too high during the compression process, because we want to achieve "approximate" isothermal compression. The entire compression process is completed by the isothermal compressor 1.

[0058] To achieve approximate isothermal compression, the cooler 2 is used to dissipate the compression heat of each stage of the isothermal compression mechanism to the external atmosphere; for this purpose, the cooler 2 is installed between every two stages of the isothermal compression mechanism to timely dissipate the compression heat.

[0059] The main purpose of adopting multi-stage isothermal expansion is as follows: through multi-stage expansion, the pressure of the working fluid is gradually reduced, avoiding large temperature differences and low efficiency during the expansion process, because we need to achieve "approximate" isothermal expansion. The entire expansion process is completed by the isothermal expander 4. To achieve approximate isothermal expansion, the working fluid air before entering the isothermal expander 4 first enters the combustion chamber 5 to mix and fully burn with the fuel, generating exhaust gas at a constant temperature to drive each stage of the isothermal expander to do work.

[0060] The fuel in the combustion chamber 5 is coal gas, natural gas, hydrogen, liquid fuel, etc. Specific Embodiment 2

[0062] As Figure 3 shown, compared with Figure 2 , the gas storage system includes a compressed air storage tank 10, a hydraulic generator 110, a pressure pump 120, and a water tank 102; the hydraulic generator 110 and the pressure pump 120 are connected in parallel between the bottom of the compressed air storage tank 10 and the bottom end of the water tank 102. The hydraulic generator 110 is used to stabilize the pressure of the compressed air after multi-stage isothermal compression when it enters the compressed air storage tank 10 through the countercurrent heat exchanger 7. During this process, the high-pressure compressed air enters the compressed air storage tank 10, and the water is forced outwards under the action of the high-pressure gas. The discharged high-pressure water drives the hydraulic generator 110 to operate and generate electricity; the water outlet of the hydraulic generator 110 is connected to the water tank 102 through a pipeline; the water inlet of the hydraulic generator 110 is communicated with the bottom end of the compressed air storage tank 10 through a pipeline. The function of the pressure pump 120 is to inject water into the compressed air storage tank 10. The water compresses the air in the compressed air storage tank 10, and the air in the compressed air storage tank 10 flows back and directly enters the countercurrent heat exchanger 7; the operation of other components is the same as that in Embodiment 1. Specific Embodiment 3

[0064] As Figure 4 shown, compared with Figure 2 , the gas storage system includes a compressed air storage tank 10. The compressed air storage tank 10 is a bag-shaped gas storage bag, making the inside and outside of the compressed air tank 10 at equal pressure; the compressed air storage tank 10 is located in deep water, and the height difference h between the position of the compressed air storage tank 10 and the horizontal plane 105 determines the pressure of the compressed air storage tank. At this time, the compressed air storage tank 10 can also be approximately considered as an isobaric compressed air storage tank.

[0065] During the energy storage process, the isothermal and adiabatic compression system generates high-pressure and high-temperature gas. The heat exchanger 7 recovers the compression heat, cools the compressed air through isobaric heat release, and stores the recovered compression heat in the energy storage medium at the same time. The pressure of the compressed air output by the isothermal and adiabatic compression system is greater than the water pressure near the deepest compressed air storage tank 10, ensuring that the compressed air can smoothly enter the compressed air storage tank 10. In the energy release working cycle, the isothermal and adiabatic expansion system is opened. The compressed gas in the compressed air storage tank 10 passes through the heat exchanger 7. The heat exchanger 7 releases the recovered compression heat to the compressed air. The compressed air absorbs heat and becomes high-temperature compressed gas, which expands and does work in the isothermal and adiabatic expansion system, driving the generator to output electricity. During the exhaust power generation process, the compressed air storage tank 10 is affected by the surrounding hydrostatic pressure, and the pressure remains basically constant, equal to the pressure generated by the water depth between the location of the compressed air storage tank 10 and the horizontal plane 104. The operation of other components is the same as that in the first embodiment.

[0066] To further improve the implementation case of the present utility model, a control scheme for the equipment of the power generation system in this embodiment is provided here, that is: a set of control device 9 is provided for the equipment of the power generation system. A relatively preferred control device is the DCS system. Using this DCS system, the components of the power generation system equipment can be comprehensively controlled hierarchically and the mutual influence between the controller devices can be reduced. The DCS control system collects the working parameters of each component of the power generation equipment, including but not limited to temperature, pressure, flow rate, stress, displacement, vibration, position, current, voltage, resistance, frequency, power, and comprehensively controls and protects the operation of each component.

Claims

1. An air medium isothermal adiabatic cycle energy storage power generation system, characterized in that: Including isothermal adiabatic compression system, isothermal adiabatic expansion system, gas storage system, low-temperature energy storage tank, high-temperature energy storage tank, energy storage medium circulation pump, heat exchanger, control device, circulating working fluid, energy storage medium and connecting pipes between them; The gas storage system comprises a compressed air storage tank, a hydraulic generator, a booster pump and a water tank; the hydraulic generator and the booster pump are connected in parallel between the bottom of the compressed air storage tank and the bottom end of the water tank; The working fluid inlet of the isothermal adiabatic compression system is directly connected to the atmosphere, the working fluid outlet of the isothermal adiabatic compression system is connected to the working fluid inlet of the isothermal adiabatic expansion system, and both are connected to one end of the working fluid medium channel of the heat exchanger; the other end of the working fluid medium channel of the heat exchanger is connected to the compressed air storage tank of the gas storage system; The low-temperature energy storage tank is installed at one end of the heat exchanger energy storage medium channel, and the other end of the heat exchanger energy storage medium channel is connected to the high-temperature energy storage tank; The energy storage medium circulation pump is installed between the low-temperature energy storage tank and the high-temperature energy storage tank.

2. The air medium isothermal adiabatic cycle energy storage power generation system according to claim 1, characterized in that: The isothermal adiabatic compression system comprises an isothermal compressor, a cooler, an adiabatic compressor and a compressed working fluid pipeline therebetween; The isothermal compressor is a multi-stage isothermal compressor; The adiabatic compressor is a multi-stage adiabatic compressor; The isothermal compressor and the adiabatic compressor are coaxially connected in series; The cooler is installed on the compressed working fluid pipeline between every two stages of isothermal compressors, and the inlet / outlet of the cooler air medium channel is respectively connected to the working fluid outlet of the previous stage isothermal compressor / the working fluid inlet of the next stage isothermal compressor; every two stages of compression mechanisms of the adiabatic compressor are directly connected through the compressed working fluid pipeline, that is, the working fluid outlet of the previous stage adiabatic compressor and the working fluid inlet of the next stage adiabatic compressor are connected through the compressed working fluid pipeline.

3. The air medium isothermal adiabatic cycle energy storage power generation system according to claim 1, characterized in that: The isothermal adiabatic expansion system comprises an isothermal expander, a combustion chamber, an adiabatic expander and a compressed working fluid pipeline; The isothermal expander is a multi-stage isothermal expander; The adiabatic expander is a multi-stage adiabatic expander; The isothermal expander and the adiabatic expander are coaxially connected in series; the outlet of the last-stage isothermal expander is connected to the inlet of the first-stage adiabatic expander through a compressed working fluid pipeline; The combustion chamber is installed on the expansion medium pipeline between each two-stage isothermal expander or on the medium pipeline between the heat exchanger and the first-stage expander. Every two stages of the adiabatic expander are connected through a compressed working fluid pipeline, that is, the working fluid outlet of the previous stage adiabatic expander and the working fluid inlet of the next stage adiabatic expander are connected through the compressed working fluid pipeline, and the working fluid outlet of the last stage adiabatic expander is directly connected to the atmosphere, and the compressed air tail gas after work is directly discharged into the environment.

4. The air medium isothermal adiabatic cycle energy storage power generation system according to claim 2, characterized in that: The isothermal compressor and the adiabatic compressor are of centrifugal or axial flow type and are composed of a multi-stage isothermal compressor and a multi-stage adiabatic compressor connected in series.

5. The air medium isothermal adiabatic cycle energy storage power generation system according to claim 3, characterized in that: The isothermal expander and the adiabatic expander are both of turbine type and are composed of multiple stages of isothermal expanders and adiabatic expanders connected in series.

6. The air medium isothermal adiabatic cycle energy storage power generation system according to claim 2, characterized in that: The cooler is a water-cooled cooler or an air-cooled cooler.

7. The air medium isothermal adiabatic cycle energy storage power generation system according to claim 1, characterized in that: The air storage system includes a compressed air storage tank, a water column and a water tank; the water column is connected to the bottom end of the compressed air storage tank and the bottom end of the water tank, and the water tank is located above the compressed air storage tank, forming a communicating vessel with the compressed air storage tank at the bottom and the water tank at the top, and the pressure of the compressed air in the compressed air storage tank is maintained equal by the gravity of the water.

8. The air medium isothermal adiabatic cycle energy storage power generation system according to claim 1, characterized in that: The air storage system comprises a compressed air storage tank, which is a bladder-shaped air storage bag; the bladder-shaped air storage bag is located in deep water.

9. The air medium isothermal adiabatic cycle energy storage power generation system according to claim 3, characterized in that: The fuel in the combustion chamber is coal gas, natural gas, hydrogen or liquid fuel.

10. The air medium isothermal adiabatic cycle energy storage power generation system according to claim 1, characterized in that: The power generation system control device is a DCS control system, which collects the operating parameters of each component of the power generation system equipment, including but not limited to temperature, pressure, flow, stress, displacement, vibration, position, current, voltage, resistance, frequency, and power, and controls and protects the operation of each component according to relevant parameters and control objectives.

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