Chemical looping heat pump electricity storage system based on tower type solar energy

Abstract

The invention discloses a chemical looping heat pump electricity storage system based on tower type solar energy, in a charging stage, high-pressure gas generated by a charging side air compressor is heated by a charging side heat regenerator and a tower type solar heat collector, then in a thermal chemical heat storage reactor, metal oxide in a high valence state is heated and decomposed into metal oxide in a low valence state, and the metal oxide is heated and decomposed into metal oxide in a low valence state; the output air enters a charging side expansion machine to do work, the exhausted air flows into a fused salt heat storage tank, and a heat storage material in the tank absorbs air heat; in the discharge stage, high-pressure air generated by a discharge side air compressor is heated by a discharge side heat regenerator and a fused salt heat storage tank, formed medium-temperature and high-pressure gas flows into a thermochemical heat storage reactor, low-valence metal oxide is promoted to be subjected to oxidation reaction at the temperature and release heat, and generated high-temperature and high-pressure gas enters a discharge side expansion machine to do work; the generator is driven to generate electricity. The device has the advantages of high energy storage density, stable energy storage form, high energy utilization rate and the like.

Description

Technical Field

[0001] The present invention belongs to the field of grid-level electricity storage and relates to a chemical chain heat pump electricity storage system based on tower-type solar energy. Background Art

[0002] Currently, grid-scale energy storage technologies primarily include the following: pumped hydro, compressed air, liquid air, hydrogen, and heat pump storage. Each of these technologies has its own unique characteristics but also corresponding limitations. Pumped hydro and compressed air storage are highly geographically sensitive: the former requires a suitable water source and a high elevation difference, while the latter relies on natural caves or requires the construction of large-scale gas storage facilities. While liquid air and hydrogen offer high energy storage density, they suffer from significant efficiency losses during the energy conversion process. Heat pump storage, as an emerging technology, converts electrical energy into heat through a heat pump cycle and stores it as sensible or latent heat. This heat is then converted back into electricity through a heat engine cycle. This technology offers significant advantages, including a small system footprint, flexible site selection, high operational efficiency, and excellent stability. However, energy storage methods based on sensible or latent heat still face technical bottlenecks, such as inevitable heat losses and limited storage density, which to some extent restrict their energy storage capabilities. Summary of the Invention

[0003] Purpose of the invention: The purpose of the present invention is to address the shortcomings of existing grid-level energy storage technology and provide a tower-type solar energy-based chemical chain heat pump energy storage system with high energy storage density and stable energy storage form.

[0004] Technical solution: The present invention is a tower-type solar energy-based chemical chain heat pump power storage system, comprising a chemical chain heat pump power storage system and a tower-type solar collector; the chemical chain heat pump power storage system comprises a charging side motor, a charging side air compressor, a thermochemical heat storage reactor, a charging side expander, a molten salt heat storage tank, a discharge side expander, a generator and a discharge side air compressor; the thermochemical heat storage reactor is filled with high-valent metal oxide MeO x , the molten salt heat storage tank is filled with heat storage material; the charging side motor and the charging side air compressor are connected; the charging side air compressor, the tower solar collector, the thermochemical heat storage reactor, the charging side expander and the molten salt heat storage tank are connected in sequence; the charging side motor, the charging side air compressor and the charging side expander are coaxially connected; the discharge side air compressor, the discharge side expander and the discharge side generator are coaxially connected; the discharge side air compressor, the molten salt heat storage tank, the thermochemical heat storage reactor and the discharge side expander are connected in sequence; the discharge side generator is connected to the discharge side expander;

[0005] Charging mode: The electric energy from the grid drives the charging side motor to operate, and the charging side motor drives the charging side air compressor to work. The charging side air compressor compresses the air from the external environment into high-pressure air and then inputs it into the tower solar collector. The tower solar collector heats the high-pressure air into high-temperature and high-pressure air. The high-temperature and high-pressure air enters the thermochemical heat storage reactor, and the high-valent metal oxide MeO x In the thermochemical heat storage reactor, it is decomposed into low-valent metal oxide MeO x-2 The air flowing out of the thermochemical heat storage reactor enters the charging side expander to perform work, and the generated electricity is supplied to the charging side air compressor; the medium-temperature and normal-pressure air flowing out of the charging side expander enters the molten salt heat storage tank, and the heat storage material stores heat energy in the form of sensible heat;

[0006] Discharge mode: The expansion machine on the discharge side drives the air compressor on the discharge side to work, and the air compressor on the discharge side compresses the air from the external environment into high-pressure air; the high-pressure air at the outlet of the discharge side compressor flows into the molten salt heat storage tank, and the heat storage material releases heat to generate medium-temperature and high-pressure air that flows out of the molten salt heat storage tank and enters the thermochemical heat storage reactor. The low-valent metal oxygen carrier MeO x-2 Oxidation reaction occurs to generate high-valent metal oxygen carrier MeO x A large amount of heat is released, and the high-temperature and high-pressure air generated flows out of the thermochemical heat storage reactor and enters the discharge side expander to perform work, driving the discharge side generator to operate, and the generated electricity is supplied to the power grid.

[0007] Furthermore, the chemical chain heat pump energy storage system also includes a charging side regenerator, the charging side air compressor is connected to the cold end of the charging side regenerator and the tower solar collector in sequence, the air at the outlet of the molten salt heat storage tank serves as the heat source of the charging side regenerator, and the high-pressure air is heated to medium-temperature high-pressure air in the charging side regenerator.

[0008] Furthermore, the chemical chain heat pump energy storage system also includes a discharge side regenerator, the discharge side air compressor is connected to the cold end of the discharge side regenerator and the molten salt heat storage tank in sequence, and the discharge side expander outlet air is connected to the hot end of the discharge side regenerator.

[0009] Furthermore, high-valent metal oxide MeO x Including (Mn 0.75 Fe 0.25 )2O3 and (Mn 0.75 Fe 0.2 Cu 0.05 )2O3.

[0010] Furthermore, the heat storage material includes Li / Na / K ternary carbonate molten salt and Mg / Na / K ternary mixed chloride salt.

[0011] Furthermore, the high-valent metal oxygen carrier MeO in the thermochemical heat storage reactor x The heat storage material in the molten salt heat storage tank adopts a continuous stacking phase arrangement with a stationary particle phase.

[0012] Furthermore, the molten salt heat storage tank adopts a mixing method of particles of multiple sizes, filling the gaps between large particles with small particles.

[0013] Furthermore, the particle shapes include spherical particles, ring-shaped particles and honeycomb particles.

[0014] Furthermore, metal heat-conducting fins for increasing the heat transfer area are provided in the thermochemical heat storage reactor and the molten salt heat storage tank.

[0015] The air and energy storage medium adopt a direct heat exchange method, which effectively improves the heat transfer efficiency and reduces heat loss, significantly optimizing the overall performance of the system.

[0016] Furthermore, the outlet pressure of the charging-side air compressor and the discharging-side air compressor is 3 to 5 atm.

[0017] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0018] Solar energy and electrical energy are converted into thermal energy through tower solar collectors and heat pump energy storage cycles. Thermal energy is stored in two forms: one is converted into stable chemical energy in metal oxides, and the other is stored in the form of sensible heat in thermal storage materials, thus achieving efficient and stable energy storage and scheduling, with the following characteristics:

[0019] (1) A metal oxide redox thermochemical heat storage system is used, with air as the working gas and solar energy and electricity as dual energy inputs. It has the advantages of no need for gas storage tanks, high operating temperature, high energy storage density and environmental friendliness. In particular, it converts heat into stable chemical energy storage, making the system both flexible and stable, providing a high energy density solution for grid-level energy storage.

[0020] (2) By setting up a molten salt heat storage tank, the waste heat is effectively recovered during the charging stage, and the expansion work output is increased during the discharge stage, thereby improving the overall energy utilization rate of the system.

[0021] (3) The system can not only integrate renewable energy power generation systems to improve power supply reliability, but also coordinate with traditional thermal power units to participate in grid frequency and peak regulation. Through the peak and valley electricity price mechanism of the power market, the operating economic efficiency of power generation enterprises can be significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural diagram of a tower-type solar energy-based chemical chain heat pump power storage system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0023] The present invention will be further described below with reference to the accompanying drawings.

[0024] Attachment Figure 1 The reference numerals in the figures are as follows:

[0025] 1. Charging side motor; 2. Charging side air compressor; 3. Charging side regenerator; 4. Tower solar collector; 5. Thermochemical heat storage reactor; 6. Charging side expander; 7. Molten salt heat storage tank; 8. Discharging side regenerator; 9. Discharging side expander; 10. Generator; 11. Discharging side air compressor; 12. Power grid.

[0026] like Figure 1 As shown, an embodiment of the present invention provides a chemical chain heat pump power storage system based on tower solar energy, including a chemical chain heat pump power storage system and a tower solar collector 4; the chemical chain heat pump power storage system includes a charging side motor 1, a charging side air compressor 2, a charging side regenerator 3, a thermochemical heat storage reactor 5, a charging side expander 6, a molten salt heat storage tank 7, a discharge side regenerator 8, a discharge side expander 9, a generator 10 and a discharge side air compressor 11.

[0027] The charging-side motor 1 is connected to the charging-side air compressor 2, which is connected to the cold-end inlet of the charging-side regenerator 3. The cold-end outlet of the charging-side regenerator 3, the tower solar collector 4, the thermochemical heat storage reactor 5, the charging-side expander 6, and the molten salt thermal storage tank 7 are connected in sequence. The molten salt thermal storage tank 7 is connected to the hot-end inlet of the charging-side regenerator 3. The charging-side motor 1, the charging-side air compressor 2, and the charging-side expander 6 are coaxially connected.

[0028] The discharge-side air compressor 11, discharge-side expander 9, and discharge-side generator 10 are coaxially connected. The discharge-side air compressor 11 is connected to the cold-end inlet of the discharge-side regenerator 8. The molten salt heat storage tank 7 is connected to the cold-end outlet of the discharge-side regenerator 8. The molten salt heat storage tank 7, thermochemical heat storage reactor 5, discharge-side expander 9, and hot-end inlet of the discharge-side regenerator 8 are sequentially connected. The discharge-side generator 10 is connected to the discharge-side expander 9.

[0029] The thermochemical heat storage reactor 5 is filled with high-valent metal oxide MeO x , including (Mn 0.75 Fe 0.25 )2O3 and (Mn 0.75 Fe 0.2 Cu 0.05 )2O3. High-valent metal oxygen carrier MeO in the thermochemical heat storage reactor 5 xThe continuous stacking phase arrangement with stationary particles is adopted, and the particle shapes include spherical particles, annular particles and honeycomb particles. The thermochemical heat storage reactor 5 is provided with metal heat conducting fins to increase the heat transfer area and enhance the heat transfer effect.

[0030] The molten salt thermal storage tank 7 is filled with a heat storage material, including Li / Na / K ternary carbonate molten salt and Mg / Na / K ternary mixed chloride salt. The thermal storage material in the molten salt thermal storage tank 7 is arranged in a continuous stacking phase with stationary particles. The particle shapes include spherical particles, annular particles, and honeycomb particles. The thermal storage particles in the molten salt thermal storage tank 7 are filled with a mixture of particles of different sizes, with small particles filling the gaps between large particles to maximize the system's energy storage density. Metal thermal conductive fins are installed inside the molten salt thermal storage tank 7 to increase the heat transfer area and enhance heat transfer efficiency.

[0031] The working principle of the tower-type solar energy-based chemical chaining heat pump power storage system provided by the embodiment of the present invention is as follows.

[0032] Charging mode:

[0033] The electric energy from the power grid 12 (or photovoltaic or wind power) drives the charging side motor 1 to operate, which drives the charging side air compressor 2 to work. The charging side air compressor 2 compresses the air from the external environment into high-pressure air and then enters the cold end of the charging side regenerator 3; the tower solar collector 4 heats the air at the cold end outlet of the charging side regenerator 3 to a high temperature and high pressure state, and the high temperature and high pressure air enters the thermochemical heat storage reactor 5, and the high-valent metal oxide MeO x In the thermochemical heat storage reactor 5, it is decomposed into low-valent metal oxide MeO x-2 ; The air flowing out of the thermochemical heat storage reactor 5 enters the charging side expander 6 to perform work, and the generated electrical energy is supplied to the charging side air compressor 2; the air flowing out of the charging side expander 6 still has residual temperature and enters the molten salt heat storage tank 7; the heat storage material in the tank absorbs the heat energy of the air through sensible heat storage; the air at the outlet of the molten salt heat storage tank 7 is used as the heat source of the charging side regenerator 3, and is then discharged to the external environment through the hot end outlet of the charging side regenerator 3, and the charging process is completed.

[0034] Discharge mode:

[0035] The discharge side expander 9 works to drive the discharge side air compressor 11 to work, and the discharge side air compressor 11 compresses the air from the external environment into high-pressure air; the high-pressure air at the outlet of the discharge side compressor 11 flows into the cold end of the discharge side regenerator 8 and the molten salt heat storage tank 7 in sequence, and the heat storage material releases heat to heat the air in the tank, and the generated medium-temperature high-pressure air flows out of the molten salt heat storage tank 7 and enters the thermochemical heat storage reactor 5; the low-valent metal oxygen carrier MeO in the thermochemical heat storage reactor 5 x-2 Oxidation reaction occurs to generate high-valent metal oxygen carrier MeOx A large amount of heat is released, and the resulting high-temperature, high-pressure air flows out of the thermochemical heat storage reactor 5 and enters the discharge-side expander 9, performing work. This drives the discharge-side generator 10, and the generated electricity is supplied to the power grid 12. The air at the outlet of the discharge-side expander 9 is discharged to the outside environment through the hot end outlet of the discharge-side regenerator 8, completing the discharge process.

[0036] The outlet pressure of the charging-side air compressor 2 and the discharging-side air compressor 11 is 3 to 5 atm.

[0037] In charging mode, the decomposition temperature of the high-valent metal oxides in the thermochemical heat storage reactor 5 is generally above 900°C. The air temperature at the inlet of the thermochemical heat storage reactor 5 must be higher than the decomposition temperature of the high-valent metal oxide carrier. The air is heated to above 1000°C by the tower solar collector 4 and flows into the thermochemical heat storage reactor 5. The high-valent metal oxides in the thermochemical heat storage reactor 5 are thermally decomposed into low-valent metal oxides. The air flowing out of the thermochemical heat storage reactor 5 enters the charging-side expander 6, where it undergoes adiabatic expansion, reducing the air temperature at the outlet of the charging-side expander 6 to approximately 550°C. The air from the outlet of the charging-side expander 6 enters the molten salt heat storage tank 7, where the heat storage material inside the tank stores thermal energy as sensible heat. The molten salt heat storage tank 7 absorbs the exhaust heat from the charging-side expander 6, reducing system losses and improving system discharge efficiency.

[0038] In discharge mode, medium-temperature, high-pressure air, heated by discharge-side regenerator 8, flows into molten salt thermal storage tank 7. After being heated to 525°C by the thermal storage material within the tank, it enters thermochemical thermal storage reactor 5. The low-valent metal oxide material within the reactor is cooled by the inlet air to below the oxidation equilibrium temperature (approximately 800°C), where an oxidation reaction occurs, releasing heat that heats the air to a high-temperature, high-pressure state. The air exiting thermochemical thermal storage reactor 5 enters discharge-side expander 9 to perform work. The addition of molten salt thermal storage tank 7 raises the temperature of the air entering discharge-side expander 9, thereby increasing the expansion work output and improving the overall energy utilization of the system.

Claims

1. A chemical chain heat pump power storage system based on tower solar energy, characterized in that: The invention comprises a chemical chain heat pump power storage system and a tower solar thermal collector (4); the chemical chain heat pump power storage system comprises a charging side motor (1), a charging side air compressor (2), a thermochemical heat storage reactor (5), a charging side expander (6), a molten salt heat storage tank (7), a discharge side expander (9), a generator (10) and a discharge side air compressor (11); the thermochemical heat storage reactor (5) is filled with a high-valent metal oxide MeO x , the molten salt heat storage tank (7) is filled with heat storage material; the charging side motor (1) and the charging side air compressor (2) are connected; the charging side air compressor (2), the tower solar collector (4), the thermochemical heat storage reactor (5), the charging side expander (6) and the molten salt heat storage tank (7) are connected in sequence; the charging side motor (1), the charging side air compressor (2) and the charging side expander (6) are coaxially connected; the discharge side air compressor (11), the discharge side expander (9) and the discharge side generator (10) are coaxially connected; the discharge side air compressor (11), the molten salt heat storage tank (7), the thermochemical heat storage reactor (5) and the discharge side expander (9) are connected in sequence; the discharge side generator (10) is connected to the discharge side expander (9); Charging mode: The electric energy from the power grid (12) drives the charging side motor (1) to operate, and the charging side motor (1) drives the charging side air compressor (2) to work. The charging side air compressor (2) compresses the air from the external environment into high-pressure air and then inputs it into the tower solar collector (4). The tower solar collector (4) heats the high-pressure air into high-temperature and high-pressure air. The high-temperature and high-pressure air enters the thermochemical heat storage reactor (5). The high-valent metal oxide MeO x In the thermochemical heat storage reactor (5), the product is decomposed into low-valent metal oxide MeO by heating. x-2 The air flowing out of the thermochemical heat storage reactor (5) enters the charge side expander (6) to perform work, and the generated electrical energy is supplied to the charge side air compressor (2); the medium temperature and normal pressure air flowing out of the charge side expander (6) enters the molten salt heat storage tank (7), and the heat storage material stores heat energy in the form of sensible heat; Discharge mode: the discharge side expander (9) drives the discharge side air compressor (11) to work, and the discharge side air compressor (11) compresses the air from the external environment into high-pressure air; the high-pressure air at the outlet of the discharge side compressor (11) flows into the molten salt heat storage tank (7), and the heat storage material releases heat to generate medium-temperature and high-pressure air that flows out of the molten salt heat storage tank (7) and enters the thermochemical heat storage reactor (5). The low-valent metal oxygen carrier MeO x-2 Oxidation reaction occurs to generate high-valent metal oxygen carrier MeO x A large amount of heat is released, and the generated high-temperature and high-pressure air flows out of the thermochemical heat storage reactor (5) and enters the discharge-side expander (9) to perform work, driving the discharge-side generator (10) to operate, and the generated electric energy is supplied to the power grid (12).

2. The tower-type solar energy-based chemical chaining heat pump power storage system according to claim 1 is characterized in that: The chemical chain heat pump power storage system further comprises a charging side regenerator (3), a charging side air compressor (2) connected in sequence to the cold end of the charging side regenerator (3) and a tower solar collector (4), air at the outlet of the molten salt heat storage tank (7) serves as a heat source for the charging side regenerator (3), and high-pressure air is heated to medium-temperature high-pressure air in the charging side regenerator (3).

3. The tower solar energy-based chemical chaining heat pump power storage system according to claim 1, characterized in that: The chemical chain heat pump power storage system further comprises a discharge side regenerator (8), a discharge side air compressor (11) connected in sequence to the cold end of the discharge side regenerator (8) and the molten salt heat storage tank (7), and the outlet air of the discharge side expander (9) is connected to the hot end of the discharge side regenerator (8).

4. The tower-type solar energy-based chemical chaining heat pump power storage system according to claim 1, characterized in that: High-valent metal oxide MeO x Including (Mn 0.75 Fe 0.25 )2O3 and (Mn 0.75 Fe 0.2 Cu 0.05 )2O3.

5. The tower-type solar energy-based chemical chaining heat pump power storage system according to claim 1, characterized in that: The heat storage materials include Li / Na / K ternary carbonate molten salt and Mg / Na / K ternary mixed chloride salt.

6. The tower-type solar energy-based chemical chaining heat pump power storage system according to claim 1, characterized in that: High-valent metal oxygen carrier MeO in thermochemical heat storage reactor (5) x The heat storage material in the molten salt heat storage tank (7) is arranged in a continuous stacking phase with a stationary particle phase.

7. The tower-type solar energy-based chemical chaining heat pump power storage system according to claim 6, characterized in that: The molten salt heat storage tank (7) adopts a mixed method of particles with multiple particle sizes, with small particles filling the gaps between large particles.

8. The tower-type solar energy-based chemical chaining heat pump power storage system according to claim 6, characterized in that: The particle shapes include spherical particles, ring particles and honeycomb particles.

9. The tower solar energy-based chemical chaining heat pump power storage system according to claim 1, characterized in that: The thermochemical heat storage reactor (5) and the molten salt heat storage tank (7) are provided with metal heat-conducting fins for increasing the heat transfer area.

10. The tower solar energy-based chemical chaining heat pump power storage system according to claim 1, characterized in that: The outlet pressure of the charging side air compressor (2) and the discharging side air compressor (11) is 3 to 5 atm.

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