Carbon dioxide multi-stage compression energy storage and release system

Abstract

The invention discloses a carbon dioxide multi-stage compression energy storage and release system which comprises a control unit, an energy storage and release water side circulation loop, an energy storage and release carbon dioxide side circulation loop and a compression type storage tank connected between the control unit and the energy storage and release water side circulation loop and used for storing water and carbon dioxide at the same time. The compression type storage tank is used for providing a high-pressure medium for the energy storage and release water side circulation loop and the energy storage and release carbon dioxide side circulation loop. Water is used for preliminarily compressing carbon dioxide, the compression ratio of a compressor in the system is greatly reduced, and therefore compression energy consumption and equipment cost are reduced. Meanwhile, the pressure of carbon dioxide is utilized to extrude the water chamber and drive the hydro-generator to generate electricity, the advantages of being stable in performance, low in cost, short in recovery period and the like are achieved, peak load shifting can be achieved, renewable energy sources can be distributed and stored, and heating and refrigerating can be achieved. The whole system has the advantages of safety, high efficiency, high energy density, flexible energy storage and release, high energy utilization rate and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage and release systems, and in particular to a carbon dioxide multi-stage compression energy storage and release system. Background Art

[0002] With the continuous development of the economy, the demand for computing power and energy consumption has increased sharply, and the demand for electricity has also increased rapidly. Power shortages are prone to occur during peak hours. In order to ensure the stable operation of the power system, improve energy utilization efficiency, and reduce operating costs, the peak-shaving and valley-filling strategy is implemented in the operation of the power grid. Energy storage technology and the use of renewable energy are important methods to achieve peak-shaving and valley-filling.

[0003] Compressed air energy storage is one of the main energy storage methods in my country. Although the technology has reached the world's leading level and has been commercialized, it has disadvantages such as low efficiency, slow response speed, unsuitability for small-scale applications, and susceptibility to geographical constraints. There is also a way to use carbon dioxide compression energy storage in the prior art, but this energy storage system relies solely on mechanical compressors, and there are problems such as high compression energy consumption and high equipment costs. Specifically, during the primary compression of carbon dioxide, due to the low density of carbon dioxide at the air inlet, many compressor stages are required, which is costly and inefficient. When releasing carbon dioxide high-pressure gas to generate electricity, the carbon dioxide generator has high costs and a long payback period. Summary of the invention

[0004] In order to solve the technical problems mentioned in the background technology, the present invention provides a carbon dioxide multi-stage compression energy storage and release system.

[0005] The present invention adopts the following technical solution: a carbon dioxide multi-stage compression energy storage and release system, including a control unit, an energy storage and release water side circulation loop, an energy storage and release carbon dioxide side circulation loop, and a compression storage tank connected between the two for simultaneously storing water and carbon dioxide, wherein the compression storage tank is used to provide high-pressure medium for the energy storage and release water side circulation loop and the energy storage and release carbon dioxide side circulation loop.

[0006] Furthermore, the energy storage and release water side circulation loop includes a water tank, a water pump, a hydro-generator, a water side inlet pipeline, and a water side outlet pipeline; The water pump is connected to the water pool through the water side inlet pipeline, and is used to pump water from the water pool and send it into the water inlet of the compression storage tank to squeeze the carbon dioxide gas in the compression storage tank; The hydro-generator is used to obtain high-pressure water from the water outlet of the compression storage tank to generate electricity; The water pool is connected to the hydro-generator through a water side outlet pipeline, so as to obtain the energy-released water for recirculation.

[0007] Furthermore, the energy storage and release carbon dioxide side circulation loop includes a compressor, a first heat exchanger, a carbon dioxide liquid tank, an expansion mechanism, a second heat exchanger, a carbon dioxide side inlet pipeline and a carbon dioxide side outlet pipeline; The compressor is connected to the gas outlet of the compression storage tank through a carbon dioxide side inlet pipeline, and is used to compress the low-pressure carbon dioxide gas obtained from the compression storage tank into high-pressure carbon dioxide gas; The first heat exchanger is connected to the compressor through a carbon dioxide side inlet pipeline, and is used to obtain high-pressure carbon dioxide gas output from the compressor output end for heating; The carbon dioxide liquid tank is in communication with the first heat exchanger and is used to store the carbon dioxide liquid after heat release; The expansion mechanism and the second heat exchanger are connected to the carbon dioxide liquid tank in sequence through the carbon dioxide side outlet pipeline, and are used to reduce the pressure of the high-pressure carbon dioxide liquid in the carbon dioxide liquid tank, absorb heat and evaporate to convert it into low-pressure carbon dioxide gas and transport it to the air inlet of the compression storage tank. The carbon dioxide gas obtained by the compression storage tank squeezes the water in the tank and is output from the water outlet of the compression storage tank into the hydro-generator.

[0008] Furthermore, the compression storage tank includes a tank body; a deformable airbag is arranged inside the tank body; the deformable airbag divides the tank body space into a liquid space containing water inside and a gas space filled with carbon dioxide gas outside; a water inlet and a water outlet connected to the liquid space are arranged at the bottom of the tank body; and an air inlet and an air outlet connected to the gas space are arranged at the top of the tank body.

[0009] Furthermore, the deformable airbag is made of plastic material.

[0010] Furthermore, the expansion mechanism is an expansion valve or an expansion machine.

[0011] Compared with the prior art, the advantages of the present invention are: the multi-stage compression storage and release system of carbon dioxide designed by the present invention uses water to preliminarily compress carbon dioxide, which greatly reduces the compression ratio of the compressor in the system, thereby reducing the compression energy consumption and equipment cost. At the same time, the pressure of carbon dioxide is used to squeeze the water chamber to drive the hydro-turbine generator to generate electricity, which has the advantages of stable performance, low cost, and short payback period. It can not only "cut peaks and fill valleys" and store renewable energy, but also generate heat and cool. The system as a whole has the advantages of safety, high efficiency, high energy density, flexible storage and release, and high energy utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic diagram of the overall structure of a first embodiment of a carbon dioxide multi-stage compression energy storage and release system according to the present invention; Figure 2It is a schematic diagram of the overall structure of Example 2 of the carbon dioxide multi-stage compression energy storage and release system of the present invention.

[0013] in: 1-compression storage tank, 2-water tank, 3-water pump, 4-hydraulic generator, 5-water side inlet pipeline, 6-water side outlet pipeline, 7-compressor, 8-first heat exchanger, 9-carbon dioxide liquid tank, 10-expansion mechanism, 11-second heat exchanger, 12-carbon dioxide side inlet pipeline, 13-carbon dioxide side outlet pipeline, 1-1-tank body, 1-2-deformable airbag. DETAILED DESCRIPTION

[0014] In order to facilitate those skilled in the art to understand the technical solution of the present invention, further description will be given below with reference to the accompanying drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention.

[0015] In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of embodiments of the present invention. However, it is apparent that one or more embodiments may be implemented without these specific details. In addition, in the following description, descriptions of known structures and techniques are omitted to avoid unnecessary confusion of concepts of the present invention.

[0016] like Figure 1 As shown, it is a schematic diagram of the overall structure of the multi-stage compression storage and release system of carbon dioxide of the present invention, including a control unit (not shown in the figure), a water side circulation loop for energy storage and release, a carbon dioxide side circulation loop for energy storage and release, and a compression storage tank 1 connected between the two for storing water and carbon dioxide at the same time. In specific implementation, the control unit is an automatic control system based on the concept of energy saving and high efficiency, integrating big data technology, computer control technology, neural network control technology, system integration technology, field bus control technology and intelligent drive technology. According to the needs, the energy storage mode or the energy release mode can be automatically, flexibly and efficiently started, the energy regulation function of the system is scientifically realized, and the energy utilization rate of the system is maximized. At the same time, according to the design requirements, the control unit also has functions such as data sharing, operation monitoring, fault alarm and various simulation calculations. In this embodiment, the compression storage tank 1 is used to provide high-pressure medium for the water side circulation loop for energy storage and release and the carbon dioxide side circulation loop for energy storage and release. The water side circulation loop for energy storage and release is mainly used for front-end water compression in the energy storage stage and rear-end water power generation in the energy release stage. The carbon dioxide side circulation loop for energy storage and release is mainly used for rear-end compressor compression and heating in the energy storage stage, and front-end carbon dioxide expansion and refrigeration in the energy release stage.

[0017] like Figure 1As shown, the energy storage and release water side circulation loop includes a water pool 2, a water pump 3, a hydro-turbine generator 4, a water side inlet pipeline 5, and a water side outlet pipeline 6. The water pump 3 is connected to the water pool 2 through the water side inlet pipeline 5, and is used to pump water from the water pool 2 and send it to the water inlet of the compression storage tank 1 to squeeze the carbon dioxide gas in the compression storage tank 1. The hydro-turbine generator 4 is used to obtain high-pressure water from the water outlet of the compression storage tank 1 to generate electricity. The water pool 2 is connected to the hydro-turbine generator 4 through the water side outlet pipeline 6 to obtain the released water for recirculation.

[0018] The energy storage and release carbon dioxide side circulation loop includes a compressor 7, a first heat exchanger 8, a carbon dioxide liquid tank 9, an expansion mechanism 10, a second heat exchanger 11, a carbon dioxide side inlet pipeline 12 and a carbon dioxide side outlet pipeline 13. The compressor 7 is connected to the gas outlet of the compression storage tank 1 through the carbon dioxide side inlet pipeline 12, which is used to compress the low-pressure carbon dioxide gas obtained from the compression storage tank 1 into high-pressure carbon dioxide gas. The first heat exchanger 8 is connected to the compressor 7 through the carbon dioxide side inlet pipeline 12, which is used to obtain the high-pressure carbon dioxide gas output from the output end of the compressor 7 for heating, providing heat to the outside world for low-temperature power generation, heating and heat storage, etc. The carbon dioxide liquid tank 9 is connected to the first heat exchanger 8, which is used to store carbon dioxide liquid after heat release. The expansion mechanism 10 and the second heat exchanger 11 are sequentially connected to the carbon dioxide liquid tank 9 through the carbon dioxide side outlet pipeline 13, and are used to reduce the pressure of the high-pressure carbon dioxide liquid in the carbon dioxide liquid tank 9 and absorb heat and evaporate to convert it into low-pressure carbon dioxide gas and transport it to the air inlet of the compression storage tank 1. The second heat exchanger 11 is used for cooling when the system operates in the energy release mode. The heat absorbed by the expansion of carbon dioxide can come from the absorption of geothermal heat or heat storage, low-temperature heat source, etc. through buried pipes. The low-temperature water after heat exchange can be used for commercial cooling, cold storage, etc. The carbon dioxide gas obtained by the compression storage tank 1 squeezes the water in the tank and outputs it from the water outlet of the compression storage tank 1 into the hydro-generator 4. In this embodiment, the expansion mechanism 10 can be set by an expansion valve.

[0019] In addition, in this embodiment, the compression storage tank 1 includes a tank body 1-1, and a diaphragm formed by a deformable airbag 1-2 is arranged inside the tank body 1-1. The deformable airbag 1-2 divides the tank body 1-1 space into a liquid space containing water inside and a gas space filled with carbon dioxide gas outside. The inside of the diaphragm is water, and the outside of the diaphragm is carbon dioxide gas. A water inlet and a water outlet connected to the liquid space are arranged at the bottom of the tank body 1-1, and an air inlet and an air outlet connected to the gas space are arranged at the top of the tank body 1-1. In specific implementation, the deformable airbag 1-2 is made of plastic material.

[0020] The specific implementation process of this embodiment is as follows: the energy storage mode is started during the off-peak period of the power grid or when receiving instructions from the power dispatching agency. The water pump 3 pumps the water in the water pool 2 into the liquid space in the compression storage tank 1, and the volume of the deformable airbag 1-2 increases, squeezing the carbon dioxide outside the deformable airbag 1-2, thereby pressurizing the carbon dioxide gas at normal pressure to a certain pressure to obtain medium-pressure carbon dioxide, thereby increasing the gaseous density of carbon dioxide. The medium-pressure carbon dioxide gas is pressurized by the compressor and condensed by the first heat exchanger 8 to become high-pressure carbon dioxide liquid stored in the carbon dioxide liquid tank 9.

[0021] The first heat exchanger 8 is used to transfer the heat energy of the carbon dioxide gas compressed by the compressor 7 to the low-temperature side medium. After the temperature of the medium is increased, it is transported to the occasion where heat is needed, such as for heating nearby offices or residents, or the heat is stored and used when needed, or the heat is used for low-temperature power generation, etc., so as to make full use of the compressed heat and improve the energy utilization rate of the system.

[0022] During the peak load period of the power grid or when receiving instructions from the power dispatching agency, the energy release mode is activated. The high-pressure carbon dioxide liquid in the carbon dioxide liquid tank 9 is reduced in pressure by the expansion valve and evaporated by the second heat exchanger 11 to become low-pressure carbon dioxide gas and enter the compression storage tank 1. The deformable airbags 1-2 are squeezed by the low-pressure carbon dioxide gas, and the water in the deformable airbags 1-2 is squeezed and transported to the hydro-generator 4 for power generation. The water coming out of the tail water pipe of the hydro-generator 4 returns to the pool, and the power generated by the hydro-generator 4 is transmitted to the power demanding occasion via the transmission line.

[0023] The second heat exchanger 11 is used to evaporate the carbon dioxide liquid after the pressure reduction by the expansion valve into carbon dioxide gas. During evaporation, it absorbs the heat of the high-temperature side medium passing through the second heat exchanger 11. After the medium is cooled, it is transported to the occasion where cooling is required, such as for commercial cooling or cold storage. The heat required for carbon dioxide gasification can also be achieved through buried pipes. The system saves energy and improves energy utilization.

[0024] like Figure 2 As shown, it is a schematic diagram of the overall structure of Example 2 of the multi-stage compression storage and release system of carbon dioxide of the present invention. The main difference from Example 1 is that in this embodiment, the expansion valve is replaced with an expander and placed behind the heat exchanger that absorbs heat, and the expander end outputs electricity through a transmission line.

[0025] In summary, the multi-stage compression storage and release system of carbon dioxide designed by the present invention uses water to preliminarily compress carbon dioxide, which greatly reduces the compression ratio of the compressor in the system, thereby reducing the compression energy consumption and equipment cost. At the same time, the pressure of carbon dioxide is used to squeeze the water chamber to drive the hydro-turbine generator to generate electricity, which has the advantages of stable performance, low cost, and short payback period. It can not only "cut peaks and fill valleys" and store renewable energy, but also provide heating and cooling. The system as a whole has the advantages of safety, high efficiency, high energy density, flexible storage and release, and high energy utilization.

[0026] The above embodiments are merely descriptions of preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A carbon dioxide multi-stage compression energy storage and release system, characterized in that: The invention comprises a control unit, an energy storage and release water side circulation loop, an energy storage and release carbon dioxide side circulation loop, and a compression storage tank (1) connected between the two and used for storing water and carbon dioxide simultaneously, wherein the compression storage tank (1) is used to provide high-pressure medium for the energy storage and release water side circulation loop and the energy storage and release carbon dioxide side circulation loop.

2. The carbon dioxide multi-stage compression energy storage and release system according to claim 1, characterized in that: The energy storage and release water side circulation loop comprises a water tank (2), a water pump (3), a hydro-generator (4), a water side inlet pipeline (5), and a water side outlet pipeline (6); The water pump (3) is connected to the water pool (2) via a water side inlet pipeline (5) and is used to pump water from the water pool (2) and send it into the water inlet of the compression storage tank (1) to compress the carbon dioxide gas in the compression storage tank (1); The hydro-generator (4) is used to obtain high-pressure water from the water outlet of the compression storage tank (1) to generate electricity; The water pool (2) is connected to the hydro-generator (4) via a water side outlet pipeline (6) for obtaining energy-released water for recirculation.

3. The carbon dioxide multi-stage compression energy storage and release system according to claim 2, characterized in that: The energy storage and release carbon dioxide side circulation loop comprises a compressor (7), a first heat exchanger (8), a carbon dioxide liquid tank (9), an expansion mechanism (10), a second heat exchanger (11), a carbon dioxide side inlet pipeline (12) and a carbon dioxide side outlet pipeline (13); The compressor (7) is connected to the gas outlet of the compression storage tank (1) via a carbon dioxide side inlet pipeline (12), and is used to compress the low-pressure carbon dioxide gas obtained from the compression storage tank (1) into high-pressure carbon dioxide gas; The first heat exchanger (8) is connected to the compressor (7) via a carbon dioxide side inlet pipeline (12) and is used to obtain high-pressure carbon dioxide gas output from the output end of the compressor (7) for heating; The carbon dioxide liquid tank (9) is in communication with the first heat exchanger (8) and is used to store the carbon dioxide liquid after heat release; The expansion mechanism (10) and the second heat exchanger (11) are sequentially connected to the carbon dioxide liquid tank (9) via a carbon dioxide side outlet pipeline (13) and are used to reduce the pressure of the high-pressure carbon dioxide liquid in the carbon dioxide liquid tank (9) and absorb heat to evaporate and convert it into low-pressure carbon dioxide gas, which is then transported to the air inlet of the compression storage tank (1). The carbon dioxide gas obtained by the compression storage tank (1) squeezes the water in the tank and is output from the water outlet of the compression storage tank (1) into the hydro-generator (4).

4. The carbon dioxide multi-stage compression energy storage and release system according to claim 1, characterized in that: The compression storage tank (1) comprises a tank body (1-1); a deformable airbag (1-2) is arranged inside the tank body (1-1); the deformable airbag (1-2) divides the space of the tank body (1-1) into a liquid space containing water inside and a gas space filled with carbon dioxide gas outside; a water inlet and a water outlet connected to the liquid space are arranged at the bottom of the tank body (1-1); and an air inlet and an air outlet connected to the gas space are arranged at the top of the tank body (1-1).

5. The carbon dioxide multi-stage compression energy storage and release system according to claim 4, characterized in that: The deformable airbag (1-2) is made of plastic material.

6. The carbon dioxide multi-stage compression energy storage and release system according to claim 5, characterized in that: The expansion mechanism (10) is an expansion valve or an expansion machine.

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