Solar-assisted chemical-looping heat pump power storage system

Abstract

The invention discloses a solar-assisted chemical-looping heat pump electricity storage system which comprises a chemical-looping heat pump electricity storage system and a tower type solar thermal collector, in a charging mode, low-pressure air output by a low-pressure air compressor is divided into two strands, one strand is compressed into high-pressure air through a high-pressure air compressor and stored in an air storage tank, and the other strand is compressed into high-pressure air through a high-pressure air compressor; the other part is heated by a first heat regenerator and a tower type solar heat collector and then input into a heat storage reaction bed layer, a high-valence metal oxygen carrier in the heat storage reaction bed layer is heated and decomposed into a low-valence metal oxygen carrier, and output reaction gas preheats low-pressure air and then enters a charging side expansion machine to do work to drive a first power generator to generate power; in the discharge mode, high-pressure air in the air storage tank is heated by the second heat regenerator and then flows into the heat storage reaction bed layer, the low-valence metal oxygen carrier is reduced, heat is released, formed high-temperature and high-pressure gas is input into the discharge side expansion machine to do work and drive the second power generator to generate power, and exhaust gas preheats the high-pressure air in the second heat regenerator. The invention has the advantages of high energy storage density and high energy storage stability.

Description

Technical Field

[0001] The present invention belongs to the field of grid-level electricity storage, and relates to a solar-assisted chemical chain heat pump electricity storage system, and specifically to a heat pump electricity storage system that utilizes a compressor and a tower solar collector to convert electrical energy and solar energy into thermal energy, and ultimately converts the energy into stable chemical energy in metal oxides for storage. Background Art

[0002] At present, the technologies that can achieve large-scale energy storage and peak load regulation include pumped storage technology, compressed air energy storage technology, liquid air energy storage technology, hydrogen storage technology, heat pump power storage technology, etc. Among them, pumped storage technology and compressed air energy storage technology are restricted by geographical location, requiring large caves that can store compressed air or additional large-capacity gas storage tanks. Although liquid air energy storage technology and hydrogen storage technology have high energy storage density, their round-trip efficiency is relatively low. As a new type of power storage technology, heat pump power storage technology works on the principle of converting electrical energy into thermal energy through a heat pump cycle and storing energy in the form of sensible heat or latent heat. It not only has the characteristics of small footprint and is not restricted by geographical location, but also has the advantages of high round-trip efficiency and stable operation. However, sensible heat or latent heat storage itself also has the disadvantages of heat not being suitable for long-term storage and limited capacity density. Summary of the invention

[0003] Purpose of the invention: The purpose of the present invention is to address the shortcomings of existing large-scale energy storage solutions and to provide a solar-assisted chemical chain heat pump power storage system with high energy storage density and high energy storage stability.

[0004] Technical solution: The solar-assisted chemical chain heat pump power storage system of the present invention comprises a chemical chain heat pump power storage system and a tower solar collector. The chemical chain heat pump power storage system comprises a low-pressure air compressor, a high-pressure air compressor, a thermal storage reaction bed, a charging side expander, a first motor, a first generator, a gas storage tank, a discharge side expander, a second generator and a diverter valve. The thermal storage reaction bed is provided with a high-valent metal oxygen carrier MeO X ; The first motor is connected to the low-pressure air compressor and the high-pressure air compressor in sequence; the low-pressure air compressor is connected to the inlet of the diverter valve, the first outlet of the diverter valve, the tower solar collector, the thermal storage reaction bed and the charging side expansion machine are connected in sequence, and the charging side expansion machine is connected to the first generator; the second outlet of the diverter valve, the high-pressure air compressor, the gas storage tank, the thermal storage reaction bed and the discharge side expansion machine are connected in sequence, and the second generator is connected to the discharge side expansion machine and the power grid;

[0005] When the power generation is greater than the power load, it operates in charging mode:

[0006] The electric energy from photovoltaic, wind power or power grid drives the first motor to operate, and the first motor drives the low-pressure air compressor and the high-pressure air compressor to work. The low-pressure air compressor compresses the air from the external environment into low-pressure air; the high-pressure air compressor further compresses the low-pressure air from the second outlet of the diverter valve into high-pressure air and stores it in the air storage tank; the tower solar collector heats the low-pressure air from the first outlet of the diverter valve into high-temperature low-pressure air and inputs it into the heat storage reaction bed, and the high-valent metal oxygen carrier MeO X Decomposed by heat into low-valent metal oxygen carrier MeO X-2 ; The first working gas flowing out of the thermal storage reaction bed is input into the charging side expander to perform work and drive the first generator to work, and the generated electric energy is supplied to the first motor;

[0007] When the power generation is less than the power load, it operates in discharge mode:

[0008] High-pressure air from the gas tank flows into the thermal storage reaction bed and reacts with 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 second working gas generated flows out of the heat storage reaction bed and is input into the discharge side expander to do work, driving the second generator to operate, and the generated electricity is supplied to the power grid.

[0009] Furthermore, the chemical chain heat pump power storage system also includes a first regenerator, the first outlet of the diverter valve is connected to the cold side inlet of the first regenerator, and the tower solar collector is connected to the cold side outlet of the first regenerator; the heat storage reaction bed is connected to the hot side inlet of the first regenerator, and the charging side expansion machine is connected to the hot side outlet of the first regenerator.

[0010] Furthermore, the chemical chain heat pump power storage system also includes a second regenerator, the gas storage tank is connected to the cold side inlet of the second regenerator, the heat storage reaction bed is connected to the cold side outlet of the second regenerator; and the discharge side expansion machine is connected to the hot side inlet of the second regenerator.

[0011] The present invention greatly improves the charging and discharging efficiency of the system by adding a regenerator to the system to recover waste heat.

[0012] Furthermore, the chemical chain heat pump power storage system also includes a waste heat utilization device, which is connected to the hot side outlet of the second heat regenerator.

[0013] Furthermore, the waste heat utilization methods of the waste heat utilization device include heating, organic Rankine cycle and seawater desalination.

[0014] Furthermore, the high-valent metal oxygen carrier MeO X Including Mn2O3, CuO and Co3O4.

[0015] Furthermore, the high-valent metal oxygen carrier MeO in the thermal storage reaction bed X A fixed bed arrangement is adopted, with fins or metal frames to enhance heat exchange, and direct contact heat exchange is carried out between air and metal oxides.

[0016] The direct heat exchange between air and energy storage material enhances the heat exchange effect, reduces the heat transfer temperature difference, and further improves the efficiency of the power storage system.

[0017] Furthermore, the low-pressure air compressor, the high-pressure air compressor and the charging-side expander are coaxially connected.

[0018] Furthermore, in the charging mode, the air flow rate flowing into the high-pressure air compressor must meet the air flow rate required for the oxidation reaction of the thermal storage reaction bed in the discharging mode; the electric energy generated by the first generator is less than the electric energy consumed by the first motor.

[0019] Furthermore, in the charging mode, the outlet pressure of the low-pressure air compressor is between 2 and 4 atm, and the outlet pressure of the high-pressure air compressor is above 5 atm.

[0020] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0021] The tower solar collector and heat pump energy storage cycle convert solar energy and electrical energy into thermal energy and store it in the form of stable chemical energy, which improves the capacity density and energy storage stability of conventional heat pump energy storage systems and has the following characteristics:

[0022] (1) Metal oxides are used as energy storage materials, air is used as the working gas, and solar energy and electricity are used as the energy input of the system. This is low-cost, clean and pollution-free. At the same time, due to the extremely high stability and reaction enthalpy change of chemical energy, it provides a set of energy storage solutions with higher flexibility, stability and capacity density.

[0023] (2) In charging mode, by installing low-pressure air compressors and high-pressure air compressors, the peak-shaving capacity of the power storage system is increased, further improving the ability to absorb renewable energy electricity.

[0024] (3) The system has a wide range of applications. It can be used in conjunction with new energy power plants to improve power generation stability. It can also be used in conjunction with thermal power plants to meet the peak load demand of the power grid. By utilizing the tiered electricity prices in the electricity market, it can also increase the profits of power plants. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic structural diagram of a solar-assisted chemical chain heat pump power storage system provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0026] The present invention will be further described below in conjunction with the accompanying drawings.

[0027] Attached Figure 1 The reference numerals in the figures are as follows:

[0028] 1. Low-pressure air compressor; 2. High-pressure air compressor; 3. First regenerator; 4. Tower solar collector; 5. Thermal storage reaction bed; 6. Charge-side expansion machine; 7. First motor; 8. First generator; 9. Gas storage tank; 10. Second regenerator; 11. Discharge-side expansion machine; 12. Second generator; 13. Waste heat utilization device; 14. Photovoltaic, wind power or power grid; 15. Diverter valve.

[0029] like Figure 1 As shown, an embodiment of the present invention provides a solar-assisted chemical chain heat pump power storage system, 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 low-pressure air compressor 1, a high-pressure air compressor 2, a first regenerator 3, a heat storage reaction bed 5, a charging side expander 6, a first motor 7, a first generator 8, a gas storage tank 9, a second regenerator 10, a discharge side expander 11, a second generator 12, a waste heat utilization device 13 and a diverter valve 15.

[0030] The first motor 7 is connected to the photovoltaic, wind power or power grid 14, and the first motor 7 is connected to the low-pressure air compressor 1 and the high-pressure air compressor 2 in sequence. The low-pressure air compressor 1, the high-pressure air compressor 2 and the charging side expander 6 are coaxially connected. The low-pressure air compressor 1 is connected to the inlet of the diverter valve 15, the first outlet of the diverter valve 15 is connected to the cold side inlet of the first regenerator 3, the tower solar collector 4 is connected to the cold side outlet of the first regenerator 3, the thermal storage reaction bed 5 is connected to the hot side inlet of the first regenerator 3, the charging side expander 6 is connected to the hot side outlet of the first regenerator 3, and the charging side expander 6 is connected to the first generator 8.

[0031] The second outlet of the diverter valve 15, the high-pressure air compressor 2 and the air storage tank 9 are connected in sequence, the air storage tank 9 is connected to the cold side inlet of the second regenerator 10, the cold side outlet of the second regenerator 10, the heat storage reaction bed 5 and the discharge side expansion machine 11 are connected in sequence, the discharge side expansion machine 11 is connected to the hot side inlet of the second regenerator 10, the waste heat utilization device 13 is connected to the hot side outlet of the second regenerator 10, and the second generator 12 is connected to the discharge side expansion machine 11 and the power grid.

[0032] The thermal storage reaction bed 5 is provided with a high-valent metal oxygen carrier MeO X , specifically Mn2O3, CuO and Co3O4, etc., which can be used in the power storage system. The high-valent metal oxygen carrier MeO in the thermal storage reaction bed 5 XA fixed bed arrangement is adopted, fins or metal frames are used to enhance heat transfer, and direct contact heat exchange is carried out between air and metal oxide to maximize the heat transfer effect.

[0033] The working principle of the solar-assisted chemical chain heat pump power storage system provided in the embodiment of the present invention is as follows.

[0034] When the power generation is greater than the power load, it operates in charging mode:

[0035] The electric energy from photovoltaic, wind power or power grid 14 (which can be called source side) drives the first motor 7 to operate, and the first motor 7 drives the low-pressure air compressor 1 and the high-pressure air compressor 2 to work. The low-pressure air compressor 1 compresses the air from the external environment into low-pressure air; the high-pressure air compressor 2 further compresses the low-pressure air from the second outlet of the diverter valve 15 into high-pressure air and stores it in the air storage tank 9; the low-pressure air at the first outlet of the diverter valve 15 is heated by the first regenerator 3 and the tower solar collector 4 to become high-temperature low-pressure air, and the high-temperature low-pressure air is input into the thermal storage reaction bed 5 to react with the high-valent metal oxygen carrier MeO X Direct contact, high-valent metal oxygen carrier MeO X Decomposed by heat into low-valent metal oxygen carrier MeO X-2 The formed first working gas flows out from the heat storage reaction bed 5 and is input into the first regenerator 3 to heat the low-pressure air from the first outlet of the diverter valve 15, and then enters the charging side expansion machine 6 to perform work and drive the first generator 8 to work, and the generated electric energy is supplied to the first motor 7; the first working gas flowing out of the charging side expansion machine 6 is close to the ambient state and is directly discharged to the external environment, and the charging process is completed.

[0036] When the power generation is less than the power load, it operates in discharge mode:

[0037] The high-pressure air from the gas storage tank 9 flows into the second regenerator 10, exchanges heat with the exhaust gas of the discharge side expander 11, and the high-pressure air after absorbing heat flows into the thermal storage reaction bed 5, and reacts with 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 second working gas generated flows out of the thermal storage reaction bed 5 and is input into the discharge side expander 11 to perform work, driving the second generator 12 to operate, and the generated electric energy is supplied to the power grid. The second working gas flowing out of the discharge side expander 11 is input into the second regenerator 10 to heat the high-pressure air from the gas storage tank 9, and then flows into the waste heat utilization device 13, completes the waste heat utilization of the second working gas, and is discharged to the external environment, and the discharge process is completed.

[0038] In the charging mode, the electric energy generated by the first generator 8 is less than the electric energy consumed by the first motor 7. The air flow rate flowing into the high-pressure air compressor 2 must meet the air flow rate required for the oxidation reaction of the thermal storage reaction bed 5 in the discharge mode. The outlet pressure of the low-pressure air compressor 1 is 2-4atm, and the outlet pressure of the high-pressure air compressor 2 is generally above 5atm.

[0039] In the charging mode, the air is heated to above 1000°C by the tower solar collector 4, and the high-valent metal oxygen carrier in the thermal storage reaction bed 5 generally decomposes at a temperature greater than 800°C. The inlet temperature of the thermal storage reaction bed 5 is higher than the decomposition temperature of the high-valent metal oxygen carrier. The low-pressure air entering the thermal storage reaction bed 5 reduces the oxygen partial pressure in the air, which can further reduce the decomposition temperature of the high-valent metal oxygen carrier.

[0040] In the discharge mode, the high-pressure air heated by the second regenerator 10 reacts with the low-valent metal oxygen carrier in the thermal storage reaction bed 5 and releases heat. The working gas reaches a temperature of 550-750°C after absorbing heat. The temperature of the working gas after absorbing heat can be changed by adjusting the mass flow rate of the working gas. The charging and discharging efficiency of the system can be improved by lowering the decomposition temperature of the high-valent metal oxygen carrier in the charging mode and increasing the heat absorption temperature of the working gas and the reaction pressure of the thermal storage reaction bed 5 in the discharge mode.

[0041] In the charging mode, by adding the first regenerator 3, the exhaust temperature of the charging side expander 6 is reduced, and the charging efficiency is improved. In the discharging mode, by adding the second regenerator 10, the temperature of the working gas entering the thermal storage reaction bed 5 is increased, the reaction rate is increased, and at the same time, the exhaust waste heat of the discharge side expander 11 is utilized, the loss is reduced, and the discharge efficiency of the system is improved.

[0042] In the charging mode, the provision of the low-pressure air compressor 1 and the high-pressure air compressor 2 improves the peak-shaving capacity of the power storage system.

[0043] In the discharge mode, the air flowing out of the second regenerator 10 still has low-temperature waste heat, which can be utilized by the waste heat utilization device 13. The waste heat utilization device 13 has many forms, and the waste heat can be utilized by heating, organic Rankine cycle, seawater desalination, etc.

Claims

1. A solar-assisted chemical chain heat pump power storage system, characterized in that: The invention comprises a chemical chain heat pump power storage system and a tower solar thermal collector (4), wherein the chemical chain heat pump power storage system comprises a low-pressure air compressor (1), a high-pressure air compressor (2), a thermal storage reaction bed (5), a charging side expansion machine (6), a first motor (7), a first generator (8), a gas storage tank (9), a discharge side expansion machine (11), a second generator (12) and a diverter valve (15), and a high-valent metal oxygen carrier MeO is arranged in the thermal storage reaction bed (5). X ; The first motor (7) is connected to the low-pressure air compressor (1) and the high-pressure air compressor (2) in sequence; the low-pressure air compressor (1) is connected to the inlet of the diverter valve (15); the first outlet of the diverter valve (15), the tower solar collector (4), the thermal storage reaction bed (5) and the charging side expansion machine (6) are connected in sequence; the charging side expansion machine (6) is connected to the first generator (8); the second outlet of the diverter valve (15), the high-pressure air compressor (2), the gas storage tank (9), the thermal storage reaction bed (5) and the discharge side expansion machine (11) are connected in sequence; the second generator (12) is connected to the discharge side expansion machine (11) and the power grid; When the power generation is greater than the power load, it operates in charging mode: The electric energy from photovoltaic power, wind power or power grid (14) drives the first motor (7) to operate, and the first motor (7) drives the low-pressure air compressor (1) and the high-pressure air compressor (2) to operate. The low-pressure air compressor (1) compresses air from the external environment into low-pressure air; the high-pressure air compressor (2) further compresses the low-pressure air from the second outlet of the diverter valve (15) into high-pressure air and stores it in the air storage tank (9); the tower solar collector (4) heats the low-pressure air from the first outlet of the diverter valve (15) into high-temperature low-pressure air and inputs it into the heat storage reaction bed (5), and the high-valent metal oxygen carrier MeO X Decomposed by heat into low-valent metal oxygen carrier MeO X-2 The first working gas flowing out of the thermal storage reaction bed (5) is input into the charging side expander (6) to perform work and drive the first generator (8) to work, and the generated electric energy is supplied to the first motor (7); When the power generation is less than the power load, it operates in discharge mode: High-pressure air from the gas storage tank (9) flows into the thermal storage reaction bed (5) and reacts with 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 second working gas flows out of the heat storage reaction bed (5) and is input into the discharge side expansion machine (11) to perform work, driving the second generator (12) to operate, and the generated electric energy is supplied to the power grid.

2. The solar-assisted chemical chaining heat pump power storage system according to claim 1 is characterized in that: The chemical chain heat pump power storage system also includes a first regenerator (3), a first outlet of a diverter valve (15) connected to a cold side inlet of the first regenerator (3), and a tower solar collector (4) connected to a cold side outlet of the first regenerator (3); a heat storage reaction bed (5) connected to a hot side inlet of the first regenerator (3), and a charging side expansion machine (6) connected to a hot side outlet of the first regenerator (3).

3. The solar-assisted chemical chaining heat pump power storage system according to claim 1 or 2, characterized in that: The chemical chain heat pump power storage system further comprises a second regenerator (10), a gas storage tank (9) connected to a cold side inlet of the second regenerator (10), a thermal storage reaction bed (5) connected to a cold side outlet of the second regenerator (10); and a discharge side expansion machine (11) connected to a hot side inlet of the second regenerator (10).

4. The solar-assisted chemical chain heat pump power storage system according to claim 3 is characterized in that: The chemical chain heat pump power storage system further comprises a waste heat utilization device (13), and the waste heat utilization device (13) is connected to the hot side outlet of the second heat regenerator (10).

5. The solar-assisted chemical chaining heat pump power storage system according to claim 4 is characterized in that: The waste heat utilization method of the waste heat utilization device (13) includes heating, organic Rankine cycle and seawater desalination.

6. The solar-assisted chemical chaining heat pump power storage system according to claim 1, characterized in that: High-valent metal oxygen carrier MeO X Including Mn2O3, CuO and Co3O4.

7. The solar-assisted chemical chaining heat pump power storage system according to claim 1, characterized in that: High-valent metal oxygen carrier MeO in the thermal storage reaction bed (5) X A fixed bed arrangement is adopted, with fins or metal frames to enhance heat exchange, and direct contact heat exchange is carried out between air and metal oxides.

8. The solar-assisted chemical chaining heat pump power storage system according to claim 1, characterized in that: The low-pressure air compressor (1), the high-pressure air compressor (2) and the charging-side expander (6) are coaxially connected.

9. The solar-assisted chemical chaining heat pump power storage system according to claim 1, characterized in that: In the charging mode, the air flow rate flowing into the high-pressure air compressor (2) must meet the air flow rate required for the oxidation reaction of the thermal storage reaction bed (5) in the discharging mode; the electric energy generated by the first generator (8) is less than the electric energy consumed by the first motor (7).

10. The solar-assisted chemical chaining heat pump power storage system according to claim 1, characterized in that: In the charging mode, the outlet pressure of the low-pressure air compressor (1) is between 2 and 4 atm, and the outlet pressure of the high-pressure air compressor (2) is above 5 atm.

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