U-shaped pipe type high-density fluid compressed air power generation system and method

Abstract

The invention discloses a U-shaped tube type high-density fluid compressed air power generation system and method, and relates to the technical field of novel energy storage and power generation, and the system comprises a compressor, a first gas-liquid heat exchanger, a heat storage tank, a second gas-liquid heat exchanger, a low-position U-shaped liquid and gas storage reservoir, a high-position liquid storage reservoir and an expansion machine. According to the compressed air power generation system, air is used as a working medium to replace water for traditional pumped storage, the air and high-density fluid flow in mutually independent pipelines respectively, and the clean air can be always kept to work in equipment such as a compressor and an expansion machine; blade corrosion and abrasion caused by the fact that a high-density fluid solution directly drives a water pump or a water turbine to do work are avoided, and the service life of equipment is prolonged; and only an anti-corrosion and anti-abrasion high-strength material needs to be adopted in the high-density fluid pipeline, so that the equipment investment cost of the whole system is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of novel energy storage and power generation, and in particular to a U-shaped tube type high-density fluid compressed air power generation system and method. Background Art

[0002] Pumped storage technology is a common way of storing electricity. It mainly uses excess electricity to pump water from a low-level reservoir to a high-level reservoir when the grid demand is low, releases water flow when the demand for electricity is high, and drives turbines to generate electricity through water flow, thereby adjusting the balance between electricity supply and demand. This technology has strong flexibility and is particularly suitable for dealing with the instability and intermittency of renewable energy such as wind power and solar energy. It is a very clean form of energy.

[0003] However, there are some obvious site selection and engineering construction difficulties in the actual application of pumped storage technology. The first is the difficulty in site selection. Pumped storage power stations are often restricted by height difference requirements. The core principle of pumped storage power stations is to achieve gravitational potential energy conversion through height difference. Therefore, sufficient vertical height difference must be considered when selecting a site, which usually needs to be between 300 meters and 500 meters. Large height difference helps to store more energy. Under smaller height difference, the water storage capacity of the reservoir is correspondingly small, which is difficult to meet the needs of large-scale power regulation. Too low height difference will reduce the energy efficiency of pumped storage and lead to higher costs, so the site selection requires specific mountainous or canyon terrain.

[0004] The second problem is the water demand. Pumped-storage power stations often require the construction of large-capacity reservoirs. Because the working fluid of a pumped-storage power station is water, if a certain level of power generation is required, a large water storage capacity must be available. For example, a 100MW pumped-storage power station requires a water storage capacity of 2 million to 3 million cubic meters. This requires not only sufficient water sources (2 million to 3 million cubic meters), but also the construction of two reservoirs (upper and lower reservoirs) with a volume of 2 million to 3 million cubic meters.

[0005] In summary, the construction of the upper and lower reservoirs and tunnels with a height difference of 300 to 500 meters, which are ultra-large in size, involves a lot of civil engineering, electromechanical installation and system integration work, and these projects often require the use of heavy machinery and professional technicians, and the construction period is long. As a result, the construction of pumped-storage power stations often requires a large investment cost and a construction period of 7 to 10 years. At present, the above problems are still the key issues restricting the large-scale promotion and application of pumped-storage power stations, and targeted improvements are urgently needed. Summary of the invention

[0006] The purpose of the present invention is to provide a U-tube high-density fluid compressed air power generation system and method, which not only solves the site selection and construction problems faced by traditional pumped storage such as large height difference and large reservoir volume, greatly reduces the amount of engineering and investment, shortens the construction period, but also provides an efficient and economical heat storage and power generation system and method.

[0007] To achieve the above-mentioned object, the present invention provides the following scheme: The present invention provides a U-shaped tube type high-density fluid compressed gas power generation system, comprising a compressor, a gas-liquid heat exchanger 1, a heat storage tank, a gas-liquid heat exchanger 2, a low-position U-shaped liquid and gas storage reservoir, a high-position liquid storage reservoir and an expander;

[0008] The air inlet pipe of the compressor, the compressor, the air outlet pipe of the compressor, the gas-liquid heat exchanger 1, and the air outlet pipe of the gas-liquid heat exchanger 1 are connected in sequence, the gas-liquid heat exchanger 1 is respectively connected to the gas-liquid heat exchanger 1 liquid inlet pipe and the gas-liquid heat exchanger 1 liquid outlet pipe, the gas-liquid heat exchanger 1 liquid outlet pipe is connected to the heat storage tank, the three-way valve 1 is respectively connected to the gas-liquid heat exchanger 1 outlet pipe, the air guide pipe, and the gas-liquid heat exchanger 2 air inlet pipe, the three-way valve 2 is respectively connected to the gas-liquid heat exchanger 1 liquid inlet pipe, the liquid guide pipe, and the gas-liquid heat exchanger 2 liquid outlet pipe, the liquid guide pipe and the low-level U The low-position U-shaped liquid storage and gas storage is connected, the low-position U-shaped liquid storage and gas storage is filled with high-density fluid, and the low-position U-shaped liquid storage and gas storage is connected to the high-position liquid storage through the upper and lower storage drainage pipes; the second air inlet pipe of the gas-liquid heat exchanger is connected to the second air outlet pipe of the gas-liquid heat exchanger through the second gas-liquid heat exchanger; the second gas-liquid heat exchanger is respectively connected to the second liquid inlet pipe of the gas-liquid heat exchanger and the second liquid outlet pipe of the gas-liquid heat exchanger; the other end of the second liquid inlet pipe of the gas-liquid heat exchanger is connected to the heat storage tank; the second air outlet pipe of the gas-liquid heat exchanger, the expander, and the air outlet pipe of the expander are connected in sequence.

[0009] In one embodiment, the high-density fluid is a fluid whose density is more than 1 times that of water; the smaller the height difference between the low-position U-shaped liquid and gas storage reservoir and the high-position liquid storage reservoir, the higher the density of the high-density fluid selected.

[0010] In one embodiment, during the entire operation of the system, the height of the high-density fluid remains unchanged; the boundary between the high-density fluid and the air always remains at the bottom of the low-position U-shaped liquid and gas storage reservoir and moves back and forth.

[0011] In one embodiment, the interior of the low-level U-shaped liquid storage and air storage reservoir is in a state where high-density fluid and air coexist; the pressure of the air in the low-level U-shaped liquid storage and air storage reservoir is the gravitational potential energy difference of the high-density fluid between the high-level liquid storage reservoir and the low-level U-shaped liquid storage and air storage reservoir; the air pressure in the low-level U-shaped liquid storage and air storage reservoir is the design pressure of the compressed air power generation system, and remains unchanged throughout the entire energy storage and power generation process.

[0012] In one embodiment, one end of the low-level U-shaped liquid and gas storage reservoir connected to the upper and lower reservoir drainage pipes is filled with high-density fluid. During the entire system operation process of energy storage and power generation, high-density fluid is always retained at one end of the low-level U-shaped liquid and gas storage reservoir connected to the upper and lower reservoir drainage pipes.

[0013] In one embodiment, one end of the low-level U-shaped liquid and gas storage reservoir connected to the air duct is filled with air, and during the entire system operation process of energy storage and power generation, air is always retained at one end of the low-level U-shaped liquid and gas storage reservoir connected to the air duct.

[0014] In one embodiment, the heat storage tank is wrapped with a heat-insulating material on the outside, and the heat storage tank is filled with a high-temperature, high-density fluid on the inside.

[0015] In one embodiment, in the entire compressed air power generation system, the pipes through which the high-density fluid flows are coated with high-strength materials that are resistant to corrosion and wear.

[0016] The present invention also provides a compressed air energy storage working method of a U-shaped tube type high-density fluid compressed air power generation system, which is applied to the above-mentioned U-shaped tube type high-density fluid compressed air power generation system and comprises the following steps:

[0017] During the off-peak period, the excess power of the power grid or the abandoned power of the new energy system drives the compressor to start rotating, and introduces the normal temperature air in the environment into the compressor through the compressor inlet pipe. The air is compressed into high-temperature and high-pressure air in the compressor and introduced into the gas-liquid heat exchanger 1 through the compressor outlet pipe. At this time, the three-way valve 2 is opened;

[0018] The normal temperature and high density fluid in the low-position U-shaped liquid storage and gas storage reservoir passes through the liquid guide pipe, three-way valve 2, and the liquid inlet pipe of the gas-liquid heat exchanger 1, and finally flows into the gas-liquid heat exchanger 1. The high temperature and high pressure air releases heat to the normal temperature and high density fluid in the gas-liquid heat exchanger 1, and after becoming normal temperature and high pressure air, it flows out from the gas outlet pipe of the gas-liquid heat exchanger 1. At this time, the three-way valve 1 is opened, and the normal temperature and high pressure air passes through the three-way valve 1 and the air guide pipe in turn, and flows into the low-position U-shaped liquid storage and gas storage reservoir;

[0019] In the compressed gas energy storage working state, as the high-pressure air in the low-level U-shaped liquid storage gas storage reservoir gradually increases, the air volume increases, pushing the high-density fluid to flow out, and the high-pressure air gradually occupies the volume at the bottom of the low-level U-shaped liquid storage gas storage reservoir; a part of the high-density fluid flows into the high-level liquid storage reservoir along the upper and lower reservoir drainage pipes, and the other part of the high-density fluid flows out through the liquid guide pipe and flows into the gas-liquid heat exchanger 1 for heat exchange; the high-temperature and high-density fluid after absorbing heat in the gas-liquid heat exchanger 1 flows into the heat storage tank through the gas-liquid heat exchanger 1 liquid outlet pipe for storage; when it reaches the gas-liquid boundary position at the bottom of one end of the low-level U-shaped liquid storage gas storage reservoir connected to the upper and lower reservoir drainage pipes, the energy storage process ends, and at this time, the three-way valve 1 and the three-way valve 2 are closed.

[0020] The present invention also provides a gravitational potential energy conversion power generation working method of a U-shaped tube high-density fluid compressed air power generation system, which is applied to the above-mentioned high-density fluid compressed air power generation system and includes the following steps:

[0021] During the peak period of electricity consumption, open the three-way valve 1, and the normal temperature and high pressure air in the low-position U-type liquid storage and gas storage reservoir enters the gas-liquid heat exchanger 2 through the air guide pipe, the three-way valve 1, and the gas-liquid heat exchanger 2 inlet pipe. At this time, the high temperature and high density fluid in the heat storage tank flows into the gas-liquid heat exchanger 2 through the gas-liquid heat exchanger 2 liquid inlet pipe; the normal temperature and high pressure air absorbs the heat of the high temperature and high density fluid in the gas-liquid heat exchanger 2, and after becoming high temperature and high pressure air, it flows out from the gas-liquid heat exchanger 2 outlet pipe, and flows into the expander to generate power, and becomes normal temperature and low pressure air, which flows out from the expander outlet pipe and is discharged into the atmosphere;

[0022] At the same time, the three-way valve 2 is opened, and the normal temperature high-density fluid after releasing heat in the gas-liquid heat exchanger 2 passes through the gas-liquid heat exchanger 2 outlet pipe, the three-way valve 2, and the liquid guide pipe, and finally flows into the low-level U-shaped liquid storage gas storage reservoir;

[0023] Under the working state of gravitational potential energy conversion power generation, as the high-pressure air in the low-level U-shaped liquid storage and gas storage reservoir is gradually discharged, the air volume decreases, and the constant gravitational potential energy difference between the high-level liquid storage reservoir and the low-level U-shaped liquid storage and gas storage reservoir pushes the high-density fluid to flow into the low-level U-shaped liquid storage and gas storage reservoir along the upper and lower reservoir drainage pipes, and combines with the high-density fluid flowing in through the liquid guide pipe to supplement the reduced air volume at the bottom of the low-level U-shaped liquid storage and gas storage reservoir; when the bottom gas-liquid boundary position of one end where the low-level U-shaped liquid storage and gas storage reservoir and the gas guide pipe are connected is reached, the power generation process ends, and at this time, three-way valve one and three-way valve two are closed.

[0024] Compared with the prior art, the present invention has achieved the following beneficial technical effects:

[0025] The U-tube high-density fluid compressed air power generation system and method of the present invention comprises a compressor, a gas-liquid heat exchanger 1, a heat storage tank, a gas-liquid heat exchanger 2, a low-level U-shaped liquid storage gas storage reservoir, a high-level liquid storage reservoir and an expander. The compressed air power generation system uses air as a working fluid to replace the water of traditional pumped storage. The air and high-density fluid flow in independent pipes respectively, which can always keep clean air working in equipment such as compressors and expanders; it avoids blade corrosion and wear caused by high-density fluid solution directly driving water pumps or turbines to work, and increases the service life of the equipment; it only needs to use high-strength materials that are resistant to corrosion and wear in high-density fluid pipelines to reduce the equipment investment cost of the entire system. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 It is a schematic diagram of a U-tube type high-density fluid compressed air power generation system;

[0028] Figure 2 It is a schematic diagram of the compressed air energy storage working state of the U-tube high-density fluid compressed air power generation system;

[0029] Figure 3 It is a schematic diagram of the flow state of high-density fluid and air in the low-position U-shaped liquid storage gas storage reservoir when the system is in the compressed gas energy storage working state;

[0030] Figure 4 It is a schematic diagram of the power generation working state of the gravitational potential energy conversion of the U-shaped tube high-density fluid compressed air power generation system;

[0031] Figure 5 It is a schematic diagram of the flow state of high-density fluid and air in the low-position U-shaped liquid storage and gas storage reservoir when the system's gravitational potential energy is converted into power generation;

[0032] In the attached figure, 1, compressor air inlet pipe; 2, compressor; 3, compressor air outlet pipe; 4, gas-liquid heat exchanger 1; 5, gas-liquid heat exchanger 1 air outlet pipe; 6, gas-liquid heat exchanger 1 liquid inlet pipe; 7, gas-liquid heat exchanger 1 liquid outlet pipe; 8, heat storage tank; 9, three-way valve 1; 10, air guide pipe; 11, gas-liquid heat exchanger 2 air inlet pipe; 12, three-way valve 2; 13, liquid guide pipe; 14, low-level U-shaped liquid and gas storage reservoir; 15, high-density fluid; 16, upper and lower reservoir drainage pipe; 17, high-level liquid storage reservoir; 18, gas-liquid heat exchanger 2; 19, gas-liquid heat exchanger 2 air outlet pipe; 20, gas-liquid heat exchanger 2 liquid inlet pipe; 21, gas-liquid heat exchanger 2 liquid outlet pipe; 22, expander; 23, expander air outlet pipe. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] The purpose of the present invention is to provide a U-shaped tube type high-density fluid compressed gas power generation system and method. By utilizing the characteristic that the gravitational potential energy of high-density fluid is greater than that of water, the height difference between the upper reservoir and the lower reservoir of a conventional pumped storage power station is reduced by multiples, the engineering workload is reduced and the applicability of the site selection is improved; by utilizing the U-shaped tube type underground storage, the high-density fluid and air are naturally divided into two areas, avoiding the gas-liquid mixing disturbance caused by the conventional gas-liquid coexistence container, and the situation where the liquid flows out with the gas; by utilizing the compressible characteristic of air, the expander is driven to work and generate electricity, which not only greatly reduces the volume of the reservoir required for the conventional pumped storage power station, greatly reduces the volume of the required liquid, but also can achieve a power generation efficiency close to that of the pumped storage system; by utilizing the high-density fluid to recover the waste heat of gas compression, and to reuse it for power generation, the system energy loss is reduced, and the reuse of high-density fluid resources and thermal energy is realized. The present invention not only solves the site selection and construction problems of large height difference and large water storage reservoir volume faced by traditional pumped storage, greatly reduces the engineering workload and investment, shortens the construction period, but also provides an efficient and economical heat storage and power generation system and method.

[0035] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] like Figure 1-Figure 5 As shown, the present invention provides a U-shaped tube type high-density fluid compressed gas power generation system, including a compressor inlet pipe 1, a compressor 2, a compressor outlet pipe 3, a gas-liquid heat exchanger 1 4, a gas-liquid heat exchanger 1 outlet pipe 5, a gas-liquid heat exchanger 1 liquid inlet pipe 6, a gas-liquid heat exchanger 1 liquid outlet pipe 7, a heat storage tank 8, a three-way valve 1 9, an air guide pipe 10, a gas-liquid heat exchanger 2 inlet pipe 11, a three-way valve 2 12, a liquid guide pipe 13, a low-position U-shaped liquid storage and gas storage reservoir 14, a high-density fluid 15, an upper and lower reservoir drainage pipe 16, a high-position liquid storage reservoir 17, a gas-liquid heat exchanger 2 18, a gas-liquid heat exchanger 2 outlet pipe 19, a gas-liquid heat exchanger 2 liquid inlet pipe 20, a gas-liquid heat exchanger 2 liquid outlet pipe 21, an expander 22, and an expander outlet pipe 23.

[0037] The compressor inlet pipe 1, the compressor 2, the compressor outlet pipe 3, the gas-liquid heat exchanger 1 4, and the gas-liquid heat exchanger 1 outlet pipe 5 are connected in sequence. In addition, the gas-liquid heat exchanger 1 4 is respectively connected to the gas-liquid heat exchanger 1 liquid inlet pipe 6 and the gas-liquid heat exchanger 1 liquid outlet pipe 7, the gas-liquid heat exchanger 1 liquid outlet pipe 7 is connected to the heat storage tank 8, the three-way valve 1 9 is respectively connected to the gas-liquid heat exchanger 1 outlet pipe 5, the air guide pipe 10, and the gas-liquid heat exchanger 2 inlet pipe 11, the three-way valve 2 12 is respectively connected to the gas-liquid heat exchanger 1 liquid inlet pipe 6, the liquid guide pipe 13, and the gas-liquid heat exchanger 2 liquid outlet pipe 21, the liquid guide pipe 13 is connected to the low-level U-shaped liquid storage and gas storage reservoir 14, the low-level U-shaped liquid storage and gas storage reservoir 14 is filled with a high-density fluid 15, and the low-level U-shaped liquid storage and gas storage reservoir 14 is connected to the high-level liquid storage reservoir 17 through the upper and lower reservoir drainage pipes 16. The gas-liquid heat exchanger 2 gas inlet pipe 11 is connected to the gas-liquid heat exchanger 2 gas outlet pipe 19 through the gas-liquid heat exchanger 2 18. In addition, the gas-liquid heat exchanger 2 18 is respectively connected to the gas-liquid heat exchanger 2 liquid inlet pipe 20 and the gas-liquid heat exchanger 2 liquid outlet pipe 21. The other end of the gas-liquid heat exchanger 2 liquid inlet pipe 20 is connected to the heat storage tank 8. The gas-liquid heat exchanger 2 gas outlet pipe 19, the expander 22, and the expander gas outlet pipe 23 are connected in sequence.

[0038] A U-tube high-density fluid compressed air power generation system includes a compressed air energy storage working state and a gravitational potential energy conversion power generation working state. The two working state processes are:

[0039] Compressed gas energy storage working process:

[0040] like Figure 2 As shown, during the off-peak period of electricity consumption, the excess electricity of the power grid or the abandonment of wind and solar power in the new energy system drives the compressor 2 to start rotating, and introduces the normal temperature air in the environment into the compressor 2 through the compressor air inlet pipe 1. The air is compressed into high-temperature and high-pressure air in the compressor 2 and introduced into the gas-liquid heat exchanger 4 through the compressor air outlet pipe 3. At this time, the three-way valve 12 is opened. The normal temperature and high-density fluid 15 in the low-level U-shaped liquid storage and gas storage reservoir 14 passes through the liquid guide pipe 13, the three-way valve 12, and the liquid inlet pipe 6 of the gas-liquid heat exchanger, and finally flows into the gas-liquid heat exchanger 4. The high-temperature and high-pressure air releases heat to the normal temperature and high-density fluid 15 in the gas-liquid heat exchanger 4, and after becoming normal temperature and high-pressure air, it flows out from the gas-liquid heat exchanger outlet pipe 5. At this time, the three-way valve 9 is opened, and the normal temperature and high-pressure air passes through the three-way valve 9 and the air guide pipe 10 in turn, and flows into the low-level U-shaped liquid storage and gas storage reservoir 14. As shown Figure 3As shown, in the compressed gas energy storage working state, as the high-pressure air in the low-position U-shaped liquid storage and gas storage reservoir 14 gradually increases, the air volume increases, pushing the high-density fluid 15 to flow out, and the high-pressure air gradually occupies the volume at the bottom of the low-position U-shaped liquid storage and gas storage reservoir 14. Part of the high-density fluid 15 flows into the high-position liquid storage reservoir 17 along the upper and lower reservoir drainage pipes 16, and part of the high-density fluid 15 flows out through the liquid guide pipe 13 and flows into the gas-liquid heat exchanger 4 for heat exchange. After absorbing heat in the gas-liquid heat exchanger 4, the high-temperature and high-density fluid 15 flows into the heat storage tank 8 through the gas-liquid heat exchanger outlet pipe 7 for storage. To achieve the above Figure 3 When the gas-liquid boundary position is shown, the energy storage process ends, and the three-way valve 1 9 and the three-way valve 2 12 are closed.

[0041] The working process of gravitational potential energy conversion to power generation:

[0042] like Figure 4 As shown, during the peak period of electricity consumption, the three-way valve 19 is opened, and the normal temperature and high pressure air in the low-position U-shaped liquid and gas storage reservoir 14 enters the gas-liquid heat exchanger 2 18 through the air guide pipe 10, the three-way valve 19, and the gas-liquid heat exchanger 2 inlet pipe 11. At this time, the high temperature and high density fluid 15 in the heat storage tank 8 flows into the gas-liquid heat exchanger 2 18 through the gas-liquid heat exchanger 2 liquid inlet pipe 20. The normal temperature and high pressure air absorbs the heat of the high temperature and high density fluid 15 in the gas-liquid heat exchanger 2 18, becomes high temperature and high pressure air, flows out from the gas-liquid heat exchanger 2 outlet pipe 19, and flows into the expander 22 to generate power, becomes normal temperature and low pressure air, flows out from the expander outlet pipe 23 and is discharged into the atmosphere. At the same time, the three-way valve 12 is opened, and the room temperature high density fluid 15 after releasing heat in the gas-liquid heat exchanger 18 passes through the gas-liquid heat exchanger 2 liquid outlet pipe 21, the three-way valve 12, and the liquid guide pipe 13, and finally flows into the low-position U-shaped liquid and gas storage reservoir 14. Figure 5 As shown, under the working state of gravitational potential energy conversion power generation, as the high-pressure air in the low-position U-shaped liquid storage and gas storage reservoir 14 is gradually discharged, the air volume decreases, and the constant gravitational potential energy difference between the high-position liquid storage reservoir 17 and the low-position U-shaped liquid storage and gas storage reservoir 14 pushes the high-density fluid 15 along the upper and lower reservoir drainage pipes 16 to flow into the low-position U-shaped liquid storage and gas storage reservoir 14, and the high-density fluid 15 that flows in through the liquid guide pipe 13 is combined to supplement the reduced air volume at the bottom of the low-position U-shaped liquid storage and gas storage reservoir 14. Figure 5 When the gas-liquid boundary position is reached, the power generation process ends and the three-way valve 1 9 and the three-way valve 2 12 are closed.

[0043] In one of the embodiments, the high-density fluid used in the present invention is a fluid with a density more than 1 times the density of water, and is safe, non-toxic, stable in nature, and less corrosive. Such high-density fluids include but are not limited to glycerol, ethylene glycol, high-concentration sugar alcohol solutions, binary or ternary mixed high-concentration salt solutions or molten salt materials composed of potassium nitrate, sodium nitrite, sodium nitrate, etc. The type of high-density fluid can be flexibly selected according to the height difference between the upper and lower reservoirs at the project construction site. If the height difference between the upper and lower reservoirs is smaller, the higher the density of the high-density fluid is selected, that is, a relatively large gravitational potential energy can be achieved under small height difference conditions. Figure 4 and Figure 5 As shown in the figure, during the whole operation of the system, the height of the high-density fluid remains unchanged. The boundary between the high-density fluid and the air always moves back and forth at the bottom of the low-position U-shaped liquid and air storage reservoir. This design can maintain the constant gravitational potential energy and air pressure of the system to the greatest extent.

[0044] In one embodiment, the low-level U-shaped liquid storage and gas storage reservoir designed by the present invention is filled with a high-density fluid inside, and at the same time, some air is always retained. The pressure of the air is the gravitational potential energy difference of the high-density fluid between the high-level liquid storage reservoir and the low-level U-shaped liquid storage and gas storage reservoir. The pressure is the design pressure of the compressed air power generation system, and the pressure remains unchanged during the entire energy storage and power generation process. The end of the low-level U-shaped liquid storage and gas storage reservoir connected to the upper and lower reservoir drainage pipes is filled with high-density fluid. During the operation of the entire system of energy storage and power generation, there is always a high-density fluid remaining at one end of the low-level U-shaped liquid storage and gas storage reservoir, thereby preventing air from flowing out through the upper and lower reservoir drainage pipes. The end of the low-level U-shaped liquid storage and gas storage reservoir connected to the air guide pipe is filled with high-density fluid. During the operation of the entire system of energy storage and power generation, there is always air remaining at one end of the low-level U-shaped liquid storage and gas storage reservoir, thereby preventing high-density fluid from flowing out through the air guide pipe.

[0045] In one embodiment, the heat storage tank designed by the present invention is wrapped with insulation materials on the outside, including but not limited to rock wool, glass wool, polystyrene foam and other materials. The inside of the heat storage tank is filled with high-temperature and high-density fluids. These high-density fluids are exchanged with the high-temperature compressed air after being compressed by the compressor in the gas-liquid heat exchanger 1, and are stored in the heat storage tank after being converted into high-temperature and high-density fluids. When generating electricity, these high-temperature and high-density fluids will heat the air in the gas-liquid heat exchanger 2, and the high-temperature air after absorbing heat will generate electricity through the expander.

[0046] The compressed air power generation system designed by the present invention uses air as the working fluid to replace the water in the traditional pumped storage. The air and high-density fluid flow in independent pipes, which can always keep clean air working in equipment such as compressors and expanders. It avoids the corrosion and wear of the blades caused by the high-density fluid solution directly driving the water pump or turbine to work, and increases the service life of the equipment. It only needs to use high-strength materials that are resistant to corrosion and wear in the high-density fluid pipeline to reduce the equipment investment cost of the entire system.

[0047] It should be noted that it is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any figure mark in the claims should not be regarded as limiting the claims involved.

[0048] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A U-tube high-density fluid compressed air power generation system, characterized in that: It includes a compressor, a gas-liquid heat exchanger 1, a heat storage tank, a gas-liquid heat exchanger 2, a low-level U-shaped liquid and gas storage reservoir, a high-level liquid storage reservoir and an expander; The air inlet pipe of the compressor, the compressor, the air outlet pipe of the compressor, the gas-liquid heat exchanger 1, and the air outlet pipe of the gas-liquid heat exchanger 1 are connected in sequence, the gas-liquid heat exchanger 1 is respectively connected to the gas-liquid heat exchanger 1 liquid inlet pipe and the gas-liquid heat exchanger 1 liquid outlet pipe, the gas-liquid heat exchanger 1 liquid outlet pipe is connected to the heat storage tank, the three-way valve 1 is respectively connected to the gas-liquid heat exchanger 1 outlet pipe, the air guide pipe, and the gas-liquid heat exchanger 2 air inlet pipe, the three-way valve 2 is respectively connected to the gas-liquid heat exchanger 1 liquid inlet pipe, the liquid guide pipe, and the gas-liquid heat exchanger 2 liquid outlet pipe, the liquid guide pipe and the low-level U The low-position U-shaped liquid storage and gas storage is connected, the low-position U-shaped liquid storage and gas storage is filled with high-density fluid, and the low-position U-shaped liquid storage and gas storage is connected to the high-position liquid storage through the upper and lower storage drainage pipes; the second air inlet pipe of the gas-liquid heat exchanger is connected to the second air outlet pipe of the gas-liquid heat exchanger through the second gas-liquid heat exchanger; the second gas-liquid heat exchanger is respectively connected to the second liquid inlet pipe of the gas-liquid heat exchanger and the second liquid outlet pipe of the gas-liquid heat exchanger; the other end of the second liquid inlet pipe of the gas-liquid heat exchanger is connected to the heat storage tank; the second air outlet pipe of the gas-liquid heat exchanger, the expander, and the air outlet pipe of the expander are connected in sequence.

2. The U-tube high-density fluid compressed air power generation system according to claim 1 is characterized in that: The high-density fluid is a fluid whose density is more than 1 times the density of water; the smaller the height difference between the low-position U-shaped liquid and gas storage reservoir and the high-position liquid storage reservoir, the higher the density of the high-density fluid selected.

3. The U-tube high-density fluid compressed air power generation system according to claim 2 is characterized in that: During the entire operation of the system, the height of the high-density fluid remains unchanged; the boundary between the high-density fluid and the air always moves back and forth at the bottom of the low-level U-shaped liquid and gas storage reservoir.

4. The U-tube high-density fluid compressed air power generation system according to claim 1 is characterized in that: The interior of the low-level U-shaped liquid storage and gas storage reservoir is a state where high-density fluid and air coexist; the pressure of the air in the low-level U-shaped liquid storage and gas storage reservoir is the gravitational potential energy difference of the high-density fluid between the high-level liquid storage reservoir and the low-level U-shaped liquid storage and gas storage reservoir; the air pressure in the low-level U-shaped liquid storage and gas storage reservoir is the design pressure of the compressed air power generation system, and remains unchanged throughout the entire energy storage and power generation process.

5. The U-tube high-density fluid compressed air power generation system according to claim 1 is characterized in that: One end of the low-level U-shaped liquid and gas storage reservoir connected to the upper and lower reservoir drainage pipes is filled with high-density fluid. During the entire system operation process of energy storage and power generation, high-density fluid is always retained at one end of the low-level U-shaped liquid and gas storage reservoir connected to the upper and lower reservoir drainage pipes.

6. The U-tube high-density fluid compressed air power generation system according to claim 1 is characterized in that: The end where the low-position U-shaped liquid and gas storage reservoir is connected to the air duct is filled with air. During the operation of the entire energy storage and power generation system, air is always retained at the end where the low-position U-shaped liquid and gas storage reservoir is connected to the air duct.

7. The U-tube high-density fluid compressed air power generation system according to claim 1 is characterized in that: The outside of the heat storage tank is wrapped with a heat-insulating material, and the inside of the heat storage tank is filled with a high-density fluid.

8. The U-tube high-density fluid compressed air power generation system according to claim 1 is characterized in that: In the entire compressed air power generation system, the pipes through which the high-density fluid flows are coated with corrosion-resistant and wear-resistant materials.

9. A compressed air energy storage working method of a U-tube high-density fluid compressed air power generation system, applied to the U-tube high-density fluid compressed air power generation system according to any one of claims 1 to 8, characterized in that: The following steps are involved: During the off-peak period of electricity consumption, the excess electricity of the power grid or the abandoned electricity of the new energy system drives the compressor to start rotating, and introduces the normal temperature air in the environment into the compressor through the compressor inlet pipe. The air is compressed into high-temperature and high-pressure air in the compressor and introduced into the gas-liquid heat exchanger 1 through the compressor outlet pipe. At this time, the three-way valve 2 is opened; The normal temperature and high density fluid in the low-position U-shaped liquid storage and gas storage reservoir passes through the liquid guide pipe, three-way valve 2, and the liquid inlet pipe of the gas-liquid heat exchanger 1, and finally flows into the gas-liquid heat exchanger 1. The high temperature and high pressure air releases heat to the normal temperature and high density fluid in the gas-liquid heat exchanger 1, and after becoming normal temperature and high pressure air, it flows out from the gas outlet pipe of the gas-liquid heat exchanger 1. At this time, the three-way valve 1 is opened, and the normal temperature and high pressure air passes through the three-way valve 1 and the air guide pipe in turn, and flows into the low-position U-shaped liquid storage and gas storage reservoir; In the compressed gas energy storage working state, as the high-pressure air in the low-level U-shaped liquid storage gas storage reservoir gradually increases, the air volume increases, pushing the high-density fluid to flow out, and the high-pressure air gradually occupies the volume at the bottom of the low-level U-shaped liquid storage gas storage reservoir; a part of the high-density fluid flows into the high-level liquid storage reservoir along the upper and lower reservoir drainage pipes, and the other part of the high-density fluid flows out through the liquid guide pipe and flows into the gas-liquid heat exchanger 1 for heat exchange; the high-temperature and high-density fluid after absorbing heat in the gas-liquid heat exchanger 1 flows into the heat storage tank through the gas-liquid heat exchanger 1 liquid outlet pipe for storage; when it reaches the gas-liquid boundary position at the bottom of one end of the low-level U-shaped liquid storage gas storage reservoir connected to the upper and lower reservoir drainage pipes, the energy storage process ends, and at this time, the three-way valve 1 and the three-way valve 2 are closed.

10. A gravitational potential energy conversion power generation working method of a U-shaped tube type high-density fluid compressed air power generation system, applied to the U-shaped tube type high-density fluid compressed air power generation system according to any one of claims 1 to 8, characterized in that: The following steps are involved: During the peak period of electricity consumption, open the three-way valve 1, and the normal temperature and high pressure air in the low-position U-type liquid storage and gas storage reservoir enters the gas-liquid heat exchanger 2 through the air guide pipe, the three-way valve 1, and the gas-liquid heat exchanger 2 inlet pipe. At this time, the high temperature and high density fluid in the heat storage tank flows into the gas-liquid heat exchanger 2 through the gas-liquid heat exchanger 2 liquid inlet pipe; the normal temperature and high pressure air absorbs the heat of the high temperature and high density fluid in the gas-liquid heat exchanger 2, and after becoming high temperature and high pressure air, it flows out from the gas-liquid heat exchanger 2 outlet pipe, and flows into the expander to generate power, and becomes normal temperature and low pressure air, which flows out from the expander outlet pipe and is discharged into the atmosphere; At the same time, the three-way valve 2 is opened, and the normal temperature high-density fluid after releasing heat in the gas-liquid heat exchanger 2 passes through the gas-liquid heat exchanger 2 outlet pipe, the three-way valve 2, and the liquid guide pipe, and finally flows into the low-level U-shaped liquid storage gas storage reservoir; Under the working state of gravitational potential energy conversion power generation, as the high-pressure air in the low-level U-shaped liquid storage and gas storage reservoir is gradually discharged, the air volume decreases, and the constant gravitational potential energy difference between the high-level liquid storage reservoir and the low-level U-shaped liquid storage and gas storage reservoir pushes the high-density fluid to flow into the low-level U-shaped liquid storage and gas storage reservoir along the upper and lower reservoir drainage pipes, and combines with the high-density fluid flowing in through the liquid guide pipe to supplement the reduced air volume at the bottom of the low-level U-shaped liquid storage and gas storage reservoir; when the bottom gas-liquid boundary position of one end where the low-level U-shaped liquid storage and gas storage reservoir and the gas guide pipe are connected is reached, the power generation process ends, and at this time, three-way valve one and three-way valve two are closed.

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