CN117605656A

CN117605656A - Carbon dioxide energy storage system and method for reducing carbon dioxide temperature floating

Info

Publication number: CN117605656A
Application number: CN202311568645.0A
Authority: CN
Inventors: 韦绍松; 田自豪
Original assignee: Baihe New Energy Technology Shenzhen Co ltd
Current assignee: Baihe New Energy Technology Shenzhen Co ltd
Priority date: 2023-11-21
Filing date: 2023-11-21
Publication date: 2024-02-27

Abstract

The embodiment of the invention discloses a carbon dioxide energy storage system which comprises a gas storage, a first gas pipeline, an energy storage loop, a liquid storage tank and an energy release loop which are sequentially connected in a closed loop, wherein the first gas pipeline is respectively communicated with the gas storage and the energy storage loop, and at least part of the first gas pipeline extends into an underground mine; the liquid storage tank is respectively communicated with the energy storage loop and the energy release loop, and the energy release loop is also communicated with the gas storage; the gaseous carbon dioxide at normal temperature and normal pressure in the gas storage can absorb heat in an underground mine when flowing through the first gas pipeline, and then enter the energy storage loop after being heated, the energy storage loop compresses and condenses the carbon dioxide into liquid, the liquid carbon dioxide in the liquid storage loop is stored in the liquid storage tank, and the liquid carbon dioxide in the liquid storage tank forms the gaseous carbon dioxide at normal temperature and normal pressure after being expanded and acted by the energy release loop and flows into the gas storage. By the mode, the embodiment of the invention can improve the temperature of the carbon dioxide entering the energy storage loop in winter.

Description

Carbon dioxide energy storage system and method for reducing carbon dioxide temperature floating

Technical Field

The embodiment of the invention relates to the technical field of carbon dioxide energy storage, in particular to a carbon dioxide energy storage system and a method for reducing carbon dioxide temperature floating.

Background

The existing carbon dioxide energy storage system comprises an energy storage process and an energy release process, wherein the energy storage process is to compress and cool carbon dioxide at normal temperature and normal pressure in a gas storage to form low-temperature liquid carbon dioxide to be stored in a carbon dioxide liquid tank, the energy release process is to gasify and heat the liquid carbon dioxide to form high-temperature and high-pressure carbon dioxide, and the high-temperature and high-pressure carbon dioxide enters an expansion machine to expand and do work to generate electricity, and then the carbon dioxide at normal temperature and normal pressure flows into the gas storage, so that energy is released. In winter, if the temperature of the carbon dioxide stored in the gas storage is low, on one hand, according to the principle of thermal expansion and contraction, the volume of the carbon dioxide of the inner membrane is reduced, the outer membrane is required to be increased to supplement air to the interlayer cavity between the inner membrane and the outer membrane in order to maintain the shape to resist wind and snow, so that the energy consumption is increased, on the other hand, the temperature of the carbon dioxide is difficult to reach the rated temperature of the inlet of the compressor, the temperature of the working medium at the outlet of the compressor is lower than the rated temperature, and the efficiency of the energy storage system is reduced. In summer, the environment temperature is high, the gaseous carbon dioxide after expansion work is only radiated in the atmosphere, the temperature of the gaseous carbon dioxide can be increased at extremely high temperature, the temperature of the gas stored in the gas storage accommodating cavity can exceed the design temperature condition of the inner membrane, and the safety risk exists.

Disclosure of Invention

In order to solve at least one of the above technical problems, one technical solution adopted in the embodiment of the present invention is: a carbon dioxide energy storage system comprises an air storage, a first air pipeline, an energy storage loop, a liquid storage tank and an energy release loop; the gas storage is used for storing gaseous carbon dioxide at normal temperature and normal pressure; one end of the first gas pipeline is communicated with an outlet of the gas storage, at least part of the first gas pipeline extends into the underground mine, and the other end of the first gas pipeline is communicated with one end of the energy storage loop; the inlet of the liquid storage tank is communicated with the other end of the energy storage loop, one end of the energy release loop is communicated with the outlet of the liquid storage tank, and the other end of the energy release loop is communicated with the gas storage; the gaseous carbon dioxide at normal temperature and normal pressure in the gas storage can absorb heat of air in an underground mine when flowing through the first gas pipeline, and then enter the energy storage loop after being heated, the energy storage loop compresses and condenses the carbon dioxide into liquid state, the liquid carbon dioxide in the liquid storage tank is stored in the liquid storage tank, and the liquid carbon dioxide in the liquid storage tank forms the gaseous carbon dioxide at normal temperature and normal pressure after being expanded and acted by the energy release loop and flows into the gas storage.

Optionally, the carbon dioxide energy storage system further comprises a second gas pipeline, one end of the second gas pipeline is communicated with the other end of the energy release loop, the other end of the second gas pipeline is communicated with the inlet of the gas storage, at least part of the second gas pipeline stretches into the underground mine, and carbon dioxide flowing out of the energy release loop can exchange heat with air in the underground mine when passing through the second gas pipeline, and flows into the gas storage after being cooled.

Optionally, the underground mine comprises a well bore and an underground tunnel, the underground tunnel is communicated with the bottom of the well bore, the first gas pipeline at least partially penetrates the well bore to extend into the underground tunnel, and the second gas pipeline at least partially penetrates the well bore to extend into the underground tunnel.

Optionally, the first gas conduit is bent and extended in the underground mine; and/or the second gas pipeline is bent and extended in the underground mine; and/or the first gas pipeline is provided with a first booster fan; and/or the second gas pipeline is provided with a second booster fan.

Optionally, the energy storage loop comprises a condenser and at least one compression energy storage part, the compression energy storage part comprises a compressor and an energy storage heat exchanger, the compressor and the energy storage heat exchanger are alternately connected, the compressor at the starting end is communicated with the first gas pipeline, the energy storage heat exchanger at the tail end is communicated with the condenser, and the condenser is communicated with the liquid storage tank.

Optionally, the energy storage loop further comprises a preheater, and the preheater is arranged between the compressor at the initial end and the first gas pipeline; and/or the first gas pipeline is provided with a first heat exchanger; and/or the second gas conduit is provided with a second heat exchanger.

Optionally, the energy release loop comprises an evaporator and at least one expansion energy release part, the expansion energy release part comprises an expander and an energy release heat exchanger, the expander and the energy release heat exchanger are alternately connected, the evaporator is connected with the liquid storage tank, the evaporator is also connected with the energy release heat exchanger at the initial end, and the expander at the tail end is connected with the gas storage.

Optionally, the first gas conduit is provided with an inlet; and/or the second gas conduit is provided with an inlet.

The embodiment of the invention adopts another technical scheme that: the carbon dioxide energy storage system comprises a gas storage, an energy storage circuit, a liquid storage tank, an energy release circuit and a second gas pipeline, wherein the gas storage, the energy storage circuit, the liquid storage tank and the energy release circuit are sequentially connected in a closed loop manner; the gas storage is used for storing gaseous carbon dioxide at normal temperature and normal pressure, the outlet of the gas storage is communicated with one end of the energy storage loop, and the other end of the energy storage loop is communicated with the inlet of the liquid storage tank; the outlet of the liquid storage tank is communicated with one end of the energy release loop, the other end of the energy release loop is communicated with one end of a second gas pipeline, at least part of the second gas pipeline stretches into the underground mine, and the other end of the second gas pipeline is communicated with the inlet of the gas storage; the gaseous carbon dioxide at normal temperature and normal pressure in the gas storage enters the energy storage loop, the energy storage loop compresses and condenses the carbon dioxide into liquid state, the liquid carbon dioxide in the liquid storage loop expands to do work through the energy release loop, and the gaseous carbon dioxide after expansion work can flow through the second gas pipeline to absorb the cold energy of the air in the underground mine, cool and flow into the gas storage for storage.

In order to solve the above technical problems, another technical solution adopted by the embodiment of the present invention is: the method for reducing the carbon dioxide temperature floating comprises the steps that when the temperature of carbon dioxide in a gas storage is lower than a first preset temperature, gaseous carbon dioxide at normal temperature and normal pressure in the gas storage can flow through a first gas pipeline, heat in an underground mine is absorbed, the heat is heated and then enters an energy storage loop, and the energy storage loop compresses and condenses the carbon dioxide into a liquid state and then stores the liquid state in a liquid storage tank; and/or when the temperature of the carbon dioxide in the gas storage is higher than a second preset temperature, the carbon dioxide flowing out of the energy release loop can flow into the gas storage after heat exchange and cooling with air in an underground mine when passing through the second gas pipeline.

The beneficial effects of the embodiment of the invention at least comprise one of the following: (1) In winter, when the temperature in the abandoned mines with wide distribution of coal mines, iron ores and copper ores is higher than the temperature of the carbon dioxide in the gas storage, the carbon dioxide from the gas storage absorbs the heat of the air in the underground mine through the first gas pipeline and then enters the energy storage loop, so that the temperature of the carbon dioxide entering the energy storage loop is increased, the temperature of the carbon dioxide is favorably increased to reach the rated temperature of the compressor in the energy storage loop, the efficiency of the energy storage system is improved, and external heat supply is reduced.

(2) The air in the underground mine space can be utilized to cool or preheat carbon dioxide in the carbon dioxide energy storage system, and the temperature of the carbon dioxide gas is regulated, so that the energy consumption of the carbon dioxide energy storage system is effectively reduced. The system is particularly suitable for preheating the gaseous carbon dioxide at the outlet of the gas storage in winter and/or cooling the gaseous carbon dioxide at the inlet of the gas storage in summer, so that energy consumption caused by weather is compensated, and the carbon dioxide energy storage system does not need to add more energy for cooling or preheating the carbon dioxide.

(3) The heat and/or cold energy requirements of the carbon dioxide energy storage system are supplemented by utilizing the difference between the air flow in the underground abandoned mine and the ground temperature, and the underground space of the abandoned mine can also be used as an extended or standby storage space of the air storage as the carbon dioxide energy storage system is built nearby the underground abandoned mine, so that the flexibility of using the carbon dioxide energy storage system is improved, and the double utilization of the ground and the underground space of the abandoned mine is realized.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. Like elements or portions are generally identified by like reference numerals throughout the several figures. In the drawings, elements or portions thereof are not necessarily drawn to scale.

FIG. 1 is a schematic diagram of a carbon dioxide energy storage system according to an embodiment of the present invention

FIG. 2 is a schematic diagram of a carbon dioxide energy storage system including a preheater according to an embodiment of the present invention

FIG. 3 is a schematic diagram of a carbon dioxide energy storage system according to an embodiment of the present invention, including a first booster fan and a first control valve;

FIG. 4 is a schematic diagram of a carbon dioxide energy storage system including a second gas conduit according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of a carbon dioxide energy storage system including a heat exchange assembly according to an embodiment of the present invention;

FIG. 6 is a schematic diagram of another carbon dioxide energy storage system provided in an embodiment of the present invention;

fig. 7 is a schematic diagram of another carbon dioxide energy storage system according to an embodiment of the invention, including a first gas conduit.

Detailed Description

In order that the invention may be readily understood, a more particular description thereof will be rendered by reference to specific embodiments that are illustrated in the appended drawings. It will be understood that when an element is referred to as being "fixed" to another element, it can be directly on the other element or one or more intervening elements may be present therebetween. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or one or more intervening elements may be present therebetween. The terms "upper," "lower," "inner," "outer," "vertical," "horizontal," and the like as used in this specification, refer to an orientation or positional relationship based on that shown in the drawings, merely for convenience of description and to simplify the description, and do not denote or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the invention. Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and/or" as used in this specification includes any and all combinations of one or more of the associated listed items.

In addition, the technical features mentioned in the different embodiments of the invention described below can be combined with one another as long as they do not conflict with one another.

In carbon dioxide energy storage systems, the carbon dioxide stored in the gas reservoir needs to be compressed, and the temperature of the carbon dioxide entering the compressor needs to be adapted to the rated operating temperature of the compressor. In order to ensure that the gas storage can store enough carbon dioxide, the occupied area of the gas storage is large, so the gas storage is usually required to be arranged on open ground, and the temperature on the ground changes in a floating way along with the change of seasons, so that the temperature of the carbon dioxide in the gas storage also changes in a floating way along with the change of seasons. Because the temperature of carbon dioxide in the gas storage is easy to be not matched with the rated working temperature of the compressor when the ground temperature is too low in winter, and the efficiency of the energy storage system is reduced, the temperature of the carbon dioxide entering the compressor needs to be controlled, and in addition, the temperature of the gas stored in the storage accommodating cavity can exceed the design temperature condition of the inner film when the ground temperature is extremely high in summer, so that the safety risk exists. The applicant finds that China has rich mineral resources, such as coal mines, iron ores, copper ores and the like, a large number of abandoned underground mines can be left after the mining is finished, the underground mines are far away from the ground, the air temperature in some underground mines has the characteristic of being warm in winter and cool in summer, and the underground mines with the underground depth not exceeding 500 meters are exemplified; while the air temperature in some underground mines remains high throughout the year, illustrative of underground mines with depths in excess of 500 meters, a common feature of these underground mines is: the air temperature in the underground mines does not change greatly with the change of seasons, and the underground mines are not searched for to be utilized in a carbon dioxide gas-liquid two-phase energy storage system.

Referring to fig. 1, a carbon dioxide energy storage system 100 according to the present invention includes: the gas storage 11, the first gas pipeline 12, the energy storage loop 13, the liquid storage tank 14 and the energy release loop 15. The gas storage 11 is used for storing carbon dioxide at normal temperature and normal pressure, at least part of the first gas pipeline 12 stretches into the underground mine 200, one end of the first gas pipeline 12 is communicated with an outlet of the gas storage 11, the other end of the first gas pipeline 12 is connected with one end of the energy storage loop 13, the other end of the energy storage loop 13 is communicated with an inlet of the liquid storage tank 14, one end of the energy release loop 15 is communicated with an outlet of the liquid storage tank 14, and the other end of the energy release loop 15 is communicated with the inlet of the gas storage 11. The energy storage loop 13 is used for compressing and condensing carbon dioxide at normal temperature and normal pressure into liquid state and storing the liquid carbon dioxide in the liquid storage tank 14, and the energy release loop 15 is used for evaporating and expanding the liquid carbon dioxide in the liquid storage tank 14 and then releasing energy to form gaseous carbon dioxide at normal temperature and normal pressure to flow into the gas storage 11. When the carbon dioxide at normal temperature and pressure in the gas storage 11 flows through the first gas pipeline 12, the carbon dioxide can exchange heat with the air in the underground mine 200, so that the temperature of the carbon dioxide entering the energy storage loop 13 can be matched with the working temperature of the compressor 1321 in the energy storage loop 13. Specifically, when the temperature of the gas storage 11 is lower than the first preset temperature (for example, during winter), the carbon dioxide can flow through the first gas pipeline 12 to absorb the heat of the air in the underground mine 200, so that the temperature of the carbon dioxide entering the energy storage loop 13 can be increased, the efficiency of the carbon dioxide energy storage system 100 is improved, the influence of the floating of the temperature of the carbon dioxide in the gas storage 11 along with the seasonal variation on the efficiency of the carbon dioxide energy storage system 100 is reduced, and the carbon dioxide energy storage system 100 operates stably throughout the year. It should be noted that the first preset temperature is a temperature of air in the underground mine 200, and the first preset temperature may be above 10 ℃. According to the embodiment, the energy of the constant-temperature air flow in the underground space of the abandoned mine is fully utilized, space and energy are reused, the running stability of the carbon dioxide energy storage system is improved, the running energy consumption of the carbon dioxide energy storage system is reduced, and energy sources are saved.

In some embodiments, carbon dioxide energy storage system 100 further includes a temperature detector (not shown) mounted to gas storage 11 for detecting the temperature of carbon dioxide in gas storage 11. Further, a temperature detector is installed in the underground mine 200 for detecting the temperature of the air in the underground mine 200. When the temperature of the carbon dioxide in the gas storage 11 is lower than the temperature of the air in the underground mine 200, the carbon dioxide can flow through the first gas pipe 12 to absorb the heat of the air in the underground mine 200, so that the temperature of the carbon dioxide entering the energy storage circuit 13 can be increased, and the efficiency of the energy storage system 100 can be improved.

In some embodiments, the carbon dioxide energy storage system 100 further comprises a first valve 16 and a second valve 17, the first valve 16 is disposed on the first gas pipe 12, the outlet of the gas storage 11 is further in direct communication with the energy storage circuit 13, and the second valve 17 is disposed between the outlet of the gas storage 11 and the energy storage circuit 13 to control communication or interception between the gas storage 11 and the energy storage circuit 13.

When the temperature of the carbon dioxide in the gas storage 11 is smaller than the first preset temperature, the first valve 16 can be opened and the second valve 17 can be closed, at this time, the gas storage 11, the first gas pipeline 12, the energy storage loop 13, the liquid storage tank 14 and the energy release loop 15 are sequentially connected to form a closed loop, the carbon dioxide at normal temperature and normal pressure in the gas storage 11 absorbs heat in the underground mine 200 when flowing through the first gas pipeline 12 and then enters the energy storage loop 13, the energy storage loop 13 compresses and condenses the carbon dioxide into liquid and then stores the liquid carbon dioxide in the liquid storage tank 14, and the liquid carbon dioxide in the liquid storage tank 14 forms carbon dioxide at normal temperature and normal pressure after expansion work of the energy release loop 15 flows into the gas storage 11. When the temperature of the carbon dioxide in the gas storage 11 is greater than or equal to the first preset temperature, the first valve 16 can be closed and the second valve 17 can be opened, at this time, the gas storage 11, the energy storage loop 13, the liquid storage tank 14 and the energy release loop 15 are sequentially connected to form a closed loop, the carbon dioxide at normal temperature and normal pressure in the gas storage 11 directly flows into the energy storage loop 13, the energy storage loop 13 compresses and condenses the carbon dioxide into liquid, the liquid carbon dioxide is stored in the liquid storage tank 14, and the liquid carbon dioxide in the liquid storage tank 14 is expanded through the energy release loop 15 to do work and is stored in the gas storage 11. In this embodiment, when the temperature of the carbon dioxide in the gas storage 11 is lower than the first preset temperature, the first valve 16 may be opened and the second valve 17 may be closed, so that the carbon dioxide in the gas storage 11 may absorb the heat of the air in the underground mine 200 when passing through the first gas pipeline 12 and then enter the energy storage circuit 13, thereby raising the temperature of the carbon dioxide entering the energy storage circuit 13, which is beneficial to making the temperature of the carbon dioxide reach the rated temperature of the compressor 1321 in the energy storage circuit 13, and ensuring that the compressor 1321 in the energy storage circuit 13 may compress the carbon dioxide.

In some embodiments, the energy storage circuit 13 includes a condenser 131 and at least one compressed energy storage portion 132, the compressed energy storage portion 132 including a compressor 1321 and an energy storage heat exchanger 1322. When the number of the compressed energy storage parts 132 is one, the outlet of the air storage 11 and the other end of the first gas pipeline 12 are both communicated with the inlet of the compressor 1321, the second valve 17 is arranged between the inlet of the compressor 1321 and the outlet of the air storage 11, the outlet of the compressor 1321 is communicated with the inlet of the energy storage heat exchanger 1322, the outlet of the energy storage heat exchanger 1322 is communicated with the condenser 131, and the condenser 131 is also communicated with the inlet of the liquid storage tank 14. The compressor 1321 is used for compressing gaseous carbon dioxide, the energy storage heat exchanger 1322 is used for absorbing heat generated during compression of the gaseous carbon dioxide to cool the carbon dioxide, and the condenser 131 is used for condensing the gaseous carbon dioxide into a liquid state. When the first valve 16 is opened and the second valve 17 is closed, the energy storage process of the carbon dioxide energy storage system 100 is: the gaseous carbon dioxide in the gas storage 11 at normal temperature and normal pressure is absorbed by the heat of the air in the underground roadway 202 when passing through the first gas pipeline 12, then enters the compressor 1321 for compression, the compressed gaseous carbon dioxide enters the energy storage heat exchanger 1322 for heat release, then the exothermic gaseous carbon dioxide enters the condenser 131 for condensation into liquid carbon dioxide, and the liquid carbon dioxide enters the liquid storage tank 14 for storage. When the first valve 16 is closed and the second valve 17 is opened, the energy storage process of the carbon dioxide energy storage system 100 is: gaseous carbon dioxide at normal temperature and normal pressure in the gas storage 11 enters the compressor 1321 to be compressed, the compressed gaseous carbon dioxide enters the energy storage heat exchanger 1322 to release heat, the released gaseous carbon dioxide enters the condenser 131 to be condensed into liquid carbon dioxide, and the liquid carbon dioxide enters the liquid storage tank 14 to be stored. Because the compressor 1321 needs to consume electric energy during operation, the energy storage process of the energy storage system 100 can be performed in the electricity consumption low-valley period, so that the surplus electric energy in the power grid can be supplied to the compressor 1321 for use, and the electric energy waste of the power grid in the electricity consumption low-valley period is reduced. When the number of the compressed energy storage parts 132 is plural, the plural compressors 1321 and the plural energy storage heat exchangers 1322 are alternately connected in sequence, and the outlet of the gas storage 11 and the other end of the first gas pipe 12 are both communicated with the inlet of the compressor 1321 at the beginning, the second valve 17 is disposed between the outlet of the gas storage 11 and the inlet of the compressor 1321 at the beginning, and the energy storage heat exchanger 1322 at the end is connected with the condenser 131. By compressing gaseous carbon dioxide multiple times using a plurality of compressors 1321, the compression ratio of gaseous carbon dioxide can be increased.

In some embodiments, referring to fig. 2, the carbon dioxide energy storage system 100 further includes a preheater 133, where the preheater 133 is disposed between the first gas pipeline 12 and the initial compressor 1321, and the preheater 133 is configured to preheat the carbon dioxide entering the initial compressor 1321, so as to ensure that the temperature of the gaseous carbon dioxide entering the initial compressor 1321 matches the working temperature of the initial compressor 1321. The temperature of the gaseous carbon dioxide coming out of the gas storage 11 or coming out of the first gas pipeline 12 is precisely adjusted through the preheater 133, the working temperature of the initial compressor 1321 is adapted, and the energy storage efficiency of the carbon dioxide energy storage system 100 is improved.

The carbon dioxide after expansion work from the energy release loop 15 flows into the gas storage 11 and can only dissipate heat in the atmosphere, and in summer, the ambient temperature is high, the temperature of the carbon dioxide in the gas storage 11 can also rise, and even in extreme high-temperature weather, the temperature of the gas stored in the accommodating cavity of the gas storage 11 can exceed the design temperature condition of the inner membrane, so that the safety risks such as rupture of the gas storage 11 exist. Thus, referring to fig. 4, the carbon dioxide energy storage system 100 further includes a second gas conduit 18. At least part of the second gas pipe 18 extends into the underground mine 200, one end of the second gas pipe 18 communicates with the other end of the energy release circuit 15, and the other end of the second gas pipe 18 communicates with the inlet of the gas reservoir 11. When the carbon dioxide flows through the second gas pipeline 18, the carbon dioxide can absorb the cold energy of the air in the underground mine 200, so that the carbon dioxide can flow into the gas storage 11 after being cooled, the influence of the environment on the temperature of the carbon dioxide after the energy release loop 15 expands and works in high temperature in summer is reduced, the carbon dioxide energy storage system 100 stably operates throughout the year, and in the extreme high temperature in summer, the temperature of the carbon dioxide flowing into the gas storage 11 can be lower than the design temperature of the gas storage 11, and the safety of the gas storage 11 is improved.

In some embodiments, the carbon dioxide energy storage system 100 further includes a third valve 19 and a fourth valve 20, the third valve 19 is disposed in the second gas pipeline 18, the fourth valve 20 is disposed between the energy release circuit 15 and the gas storage 11, and the fourth valve 20 is used to control communication or interception between the energy release circuit 15 and the inlet of the gas storage 11. When the temperature of the carbon dioxide in the gas storage 11 is higher than the second preset temperature, the third valve 19 can be opened and the fourth valve 20 can be closed, and at this time, when the carbon dioxide expanded and acting from the energy release loop 15 passes through the second gas pipeline 18, the air in the underground mine 200 absorbs the cold energy of the carbon dioxide flowing through the second gas pipeline 18 and flows into the gas storage 11, so that the temperature of the carbon dioxide in the gas storage 11 can be reduced to the design temperature condition of the gas storage 11, and the safety of the gas storage 11 is improved. When the temperature of the carbon dioxide in the gas storage 11 is lower than or equal to the second preset temperature, the third valve 19 may be closed and the fourth valve 20 may be opened, at which time the carbon dioxide expanded from the energy release circuit 15 directly flows into the gas storage 11. The second preset temperature is lower than the carbon dioxide temperature after the energy release circuit 15 expands to perform work, specifically, the second preset temperature may be below 40 ℃, which is illustrated as the temperature of the air in the underground mine 200. In this embodiment, when the temperature of the carbon dioxide after the expansion work of the energy release circuit 15 is higher than the second preset temperature, the third valve 19 is opened and the fourth valve 20 is closed, so that the carbon dioxide after the expansion work of the energy release circuit 15 is cooled in the second gas pipeline 18 and then flows into the gas storage 11, the influence of the environment on the temperature of the carbon dioxide after the expansion work of the energy release circuit 15 in summer is reduced, the carbon dioxide energy storage system 100 operates stably throughout the year, and when the temperature is extremely high in summer, the temperature of the carbon dioxide flowing into the gas storage 11 is lower than the design temperature of the gas storage 11, and the safety of the gas storage 11 is improved.

It should be noted that, when the carbon dioxide energy storage system 100 is disposed near the underground mine 200 with warmth in winter and cool in summer, the first gas pipeline 12 and the second gas pipeline 18 may be disposed in the carbon dioxide energy storage system 100 at the same time, so that the first valve 16 may be opened and the second valve 17 may be closed when the temperature of the carbon dioxide in the gas storage 11 is lower than the first preset temperature in the energy storage stage, so that the carbon dioxide flows through the first gas pipeline 12 to absorb the heat of the air in the underground mine 200, and the temperature of the carbon dioxide is raised and then enters the energy storage loop 13; in the energy release stage, when the temperature of the carbon dioxide in the gas storage 11 is higher than a second preset temperature, the third valve 19 can be opened, and the fourth valve 20 can be closed, so that the carbon dioxide after the energy release loop 15 expands and works can flow through the second gas pipeline 18 to transfer heat to the air in the underground mine 200, and the carbon dioxide flows into the gas storage 11 for storage after being cooled; when the temperature of the carbon dioxide in the gas storage 11 is greater than or equal to the first preset temperature and less than or equal to the second preset temperature, the second valve 17 may be opened and the first valve 16 may be closed in the energy storage stage, so that the carbon dioxide in the gas storage 11 directly enters the energy storage circuit 13, and the fourth valve 20 may be opened and the third valve 19 may be closed in the energy release stage, so that the carbon dioxide flowing out of the energy release circuit 15 may directly flow into the gas storage 11. When the carbon dioxide energy storage system 100 is installed in the underground mine 200 kept at a high temperature throughout the year, only the first gas pipeline 12 is required to be installed in the carbon dioxide energy storage system 100, so that when the temperature of the carbon dioxide in the gas storage 11 is lower than the first preset temperature, the carbon dioxide can flow through the first gas pipeline 12 to absorb the heat of the air in the underground mine 200, and then the temperature of the carbon dioxide is increased and then enters the energy storage loop 13.

In some embodiments, the first gas conduit 12 is provided with an inlet (not shown), and/or the second gas conduit 18 is provided with an inlet. When the carbon dioxide energy storage system is initially filled with gaseous carbon dioxide into the carbon dioxide energy storage system 100 (such as the gas storage 11, the energy storage loop 13, the liquid storage tank 14 and the energy release loop 15), an outlet of a vaporizer (not shown) for filling carbon dioxide into the carbon dioxide energy storage system 100 can be connected with an inlet of the first gas pipeline 12 and/or an inlet of the second gas pipeline 18, so that low-temperature gaseous carbon dioxide from the vaporizer and air in the underground mine 200 are fully exchanged and then enter the carbon dioxide energy storage system 100, and further, the temperature of the gaseous carbon dioxide entering the carbon dioxide energy storage system 100 is not too low, the efficiency and stable operation of the carbon dioxide energy storage system 100 are not affected, so that the temperature of the carbon dioxide entering the gas storage system 11 is stabilized within a design range, the energy consumption is increased due to the fact that the air supplement of an interlayer cavity between an inner film and an outer film is not required to be additionally increased, and the efficiency of the carbon dioxide energy storage system 100 is prevented from being reduced. The vaporizer is used for vaporizing the liquid carbon dioxide in the tank truck and then heating the liquid carbon dioxide by the first gas pipeline 12 and/or the second gas pipeline 18 and then filling the liquid carbon dioxide into the carbon dioxide energy storage system 100 when the carbon dioxide energy storage system is initialized.

In some embodiments, the underground mine 200 includes a well bore 201 and an underground tunnel 202, the underground tunnel 202 being in communication with a bottom of the well bore 201, the first gas conduit 12 extending at least partially through the well bore 201 into the underground tunnel 202, and the second gas conduit 18 extending at least partially through the well bore 201 into the underground tunnel 202. Wherein the distance between the underground tunnel 202 and the ground is typically over 100 meters, the air temperature in the underground tunnel 202 varies less with the season, and the air temperature in the underground tunnel 202 tends to be lower than the air temperature on the ground during the summer so that the air in the underground tunnel 202 can absorb the heat of the carbon dioxide flowing through the second gas pipe 18, and the air temperature in the underground tunnel 202 tends to be higher than the air temperature on the ground during the winter so that the carbon dioxide flowing through the first gas pipe 12 can absorb the heat of the air in the underground tunnel 202.

In some embodiments, the number of the shafts 201 is at least two, and by taking two shafts 201 as an example, the bottom of each shaft 201 is communicated with the underground roadway 202, two ends of the first gas pipeline 12 respectively extend out of the two shafts 201, one end of the first gas pipeline is connected with the gas storage, and the other end of the first gas pipeline is connected with the energy storage loop 13; two ends of the second gas pipeline 18 extend out of the two shafts 201 respectively, one end of the second gas pipeline is connected with the energy release circuit 15, and the other end of the second gas pipeline is connected with a gas storage.

In some embodiments, the first gas conduit 12 extends in a bend in the underground roadway 202, which is advantageous in that carbon dioxide flowing through the first gas conduit 12 may better absorb heat from air in the underground roadway 202. Meanwhile, as the first gas pipeline 12 is bent and extended in the underground roadway 202, the first valve 16 is always opened, and the first gas pipeline 12 is used as a storage space of carbon dioxide, so that the space for containing carbon dioxide at normal temperature and normal pressure in the carbon dioxide energy storage system 100 is enlarged, the carbon dioxide energy storage system 100 can contain more carbon dioxide, and the carbon dioxide working medium which can be stored by the carbon dioxide energy storage system 100 is enlarged.

In some embodiments, second gas conduit 18 extends in a bend in underground roadway 202, which is advantageous in that air in underground roadway 202 may better absorb the cold energy of carbon dioxide flowing through second gas conduit 18. The third valve 19 is always opened, and the second gas pipeline 18 is used as a storage space of carbon dioxide, and the second gas pipeline 18 is bent and extended in the underground roadway 202, so that the space for containing carbon dioxide at normal temperature and normal pressure in the carbon dioxide energy storage system 100 is enlarged, and the carbon dioxide energy storage system 100 can contain more carbon dioxide, so that carbon dioxide working media which can be stored by the carbon dioxide energy storage system 100 are enlarged.

In some embodiments, referring to fig. 3, the first gas conduit 12 is provided with a first booster fan 121 and/or, referring to fig. 4, the second gas conduit 18 is provided with a second booster fan 181.

When the carbon dioxide gas flows through the first gas pipeline 12, if the shaft 201 and the underground roadway 202 are long, the pressure of the carbon dioxide gas at the outlet of the first gas pipeline 12 is greatly reduced, and the low-pressure carbon dioxide gas enters the compressor 1321 to cause the operation of the compressor 1321 to deviate greatly, and by arranging the first booster fan 121, the pressure drop of the carbon dioxide gas flowing through the first gas pipeline 12 can be compensated, so that the normal operation of the compressor 1321 is not affected. Illustratively, the first booster fan 121 is disposed between an end of the first gas conduit 12 proximate the outlet of the wellbore 201 and the compressor 1321. The outlet of the well bore 201 and the inlet of the well bore 201 are determined according to the flow direction of carbon dioxide gas, and the carbon dioxide gas always enters the underground mine from the inlet of the well bore 201 along the first gas pipe 12/the second gas pipe 18, and flows out of the underground mine from the outlet of the well bore 201.

Similarly, when the carbon dioxide gas flows through the second gas pipeline 18, by arranging the second booster fan 181, the pressure drop of the carbon dioxide gas flowing through the second gas pipeline 18 can be compensated, so that the problem that the outlet pressure of the expander 1521 (when a plurality of expanders 1521 are connected with the gas storage in the case that the number of the expanders 1521 is increased due to the fact that the low-pressure carbon dioxide gas cannot enter the gas storage 11 and the gas storage is increased in the pipeline is avoided, and the expander 1521 deviates from the rated operation working condition of the expander, thereby ensuring the normal operation of the carbon dioxide energy storage system 100. Illustratively, the second booster fan 181 is disposed between the end of the second gas conduit 18 proximate the outlet of the well bore 201 and the gas reservoir 11.

Further, referring to fig. 4, a first control valve 122 may be further disposed on the first gas pipeline 12, if a first booster fan 121 is disposed, the first control valve 122 is disposed between the first booster fan 121 and an end of the first gas pipeline 12 near the outlet of the wellbore 201, and when the first control valve 122 is opened, the first gas pipeline 12 is turned on, and the first booster fan 121 is opened. If the first booster fan 121 is not provided, the first control valve 122 is disposed between one end of the first gas pipeline 12 near the outlet of the shaft 201 and the inlet of the compressor 1321, and controls whether the carbon dioxide gas after heat exchange and temperature rise of the first gas pipeline 12 in the underground mine flows into the compressor 1321. When the first control valve 122 is opened, carbon dioxide gas after heat exchange and temperature rise of the first gas pipeline 12 can flow into the compressor 1321, and when the first control valve 122 is closed, the compressor 1321 is isolated from the first gas pipeline 12, and the first gas pipeline 12 can serve as a standby storage space of the gas storage 11, so that the flexibility of using the carbon dioxide energy storage system 100 is improved.

Further, when the second air pipeline 18 is provided with the second booster fan 181, the second air pipeline 18 can be further provided with a second control valve 182, the second control valve 182 is arranged between one end of the second air pipeline 182, which is close to the outlet of the shaft 201, and the second booster fan 181, when the second control valve 182 is opened, the second air pipeline 18 is conducted, the second booster fan 181 is opened, when the second control valve 182 is closed, the second booster fan 181 is closed, and at the moment, if the fourth valve 20 is opened, carbon dioxide in the second air pipeline 182 in the underground mine can exchange heat with air in the underground mine sufficiently for cooling. If the second booster fan 181 is not arranged, the second control valve 182 is arranged between one end of the second gas pipeline 18, which is close to the outlet of the shaft 201, and the inlet of the gas storage 11, and controls whether the carbon dioxide gas after heat exchange and temperature reduction of the first gas pipeline 12 in the underground mine flows into the gas storage 11. When the second control valve 182 is opened, the carbon dioxide gas after heat exchange and temperature reduction of the second gas pipeline 18 can flow into the gas storage 11, when the gas storage 11 is full, the carbon dioxide gas can also serve as a storage space of the gas storage 11, when the second control valve 182 is closed, the gas storage 11 is isolated from the first gas pipeline 12, the use of the gas storage 11 is not affected, the carbon dioxide energy storage system 100 is applicable in winter, the carbon dioxide gas at the outlet of the cooling expansion machine 1521 does not need to be cooled through the second gas pipeline 18 (when a plurality of expansion machines 1521 are arranged, the carbon dioxide gas at the outlet of the nearest expansion machine 1521 is connected with the gas storage), and the flexibility of the use of the carbon dioxide energy storage system 100 is improved.

In some embodiments, referring to fig. 4, the first gas conduit 12 is further provided with a first heat exchanger 123; and/or the second gas conduit 18 is provided with a second heat exchanger 183. When the first gas pipe 12 is provided with the first heat exchanger 123, the first heat exchanger 123 may be located in the underground mine 200, and the first heat exchanger 123 may provide heat for carbon dioxide by using air of the underground mine, compared with using only the first gas pipe 12, the temperature of the carbon dioxide flowing through the first gas pipe 12 may be further increased, so that the temperature of the carbon dioxide is adapted to the working temperature of the initial end compressor 1321, and the energy storage efficiency of the carbon dioxide energy storage system 100 is improved. When the second gas pipeline 18 is provided with the second heat exchanger 183, the second heat exchanger 183 can be located in the underground mine 200, when carbon dioxide flows through the second heat exchanger 183, the second heat exchanger 183 can provide cold energy for the carbon dioxide by utilizing air of the underground mine so as to cool the carbon dioxide, compared with the method that the temperature of the carbon dioxide entering the gas storage 11 can be further reduced by utilizing the second gas pipeline 18 only, the influence of the environment on the temperature of the carbon dioxide after the expansion work of the energy release loop 15 in summer can be further reduced, the carbon dioxide energy storage system 100 can be stably operated throughout the year, the temperature of the carbon dioxide flowing into the gas storage 11 can be further ensured to be lower than the design temperature of the gas storage 11, and the safety of the gas storage 11 can be improved.

In some embodiments, the energy release circuit 15 includes an evaporator 151 and at least one expansion energy release portion 152, the expansion energy release portion 152 including an energy release heat exchanger 1522 and an expander 1521. When the number of the expansion energy release parts 152 is one, the outlet of the evaporator 151 is communicated with the inlet of the energy release heat exchanger 1522, the inlet of the expansion machine 1521 is communicated with the outlet of the energy release heat exchanger 1522, the inlet of the gas storage 11 and one end of the second gas pipeline 18 are both communicated with the outlet of the expansion machine 1521, and the fourth valve 20 is arranged between the inlet of the gas storage 11 and the outlet of the expansion machine 1521. The evaporator 151 is used for evaporating liquid carbon dioxide into a gaseous state, the energy release heat exchanger 1522 is used for providing heat for the carbon dioxide, and the expander 1521 is used for generating electricity. When the third valve 19 is opened and the fourth valve 20 is closed, the carbon dioxide energy storage system 100 releases energy by: the liquid carbon dioxide in the liquid storage tank 14 enters the evaporator 151 to be evaporated into high-pressure gaseous carbon dioxide, the high-pressure gaseous carbon dioxide enters the energy release heat exchanger 1522 to absorb heat to form high-temperature high-pressure carbon dioxide, the high-temperature high-pressure carbon dioxide enters the expander 1521 to expand and do work, the expander 1521 drives the generator to generate electricity, the pressure and the temperature of the carbon dioxide flowing out of the expander 1521 are reduced, and then the carbon dioxide flows into the gas storage 11 through the second gas pipeline 18, wherein the air in the underground roadway 202 can absorb the heat of the carbon dioxide flowing through the second gas pipeline 18, so that the temperature of the carbon dioxide is further reduced to the design temperature of the gas storage 11, and the safety of the gas storage 11 is improved. When the third valve 19 is closed and the fourth valve 20 is opened, the carbon dioxide energy storage system 100 releases energy by: the liquid carbon dioxide in the liquid storage tank 14 enters the evaporator 151 to be evaporated into high-pressure gaseous carbon dioxide, the high-pressure gaseous carbon dioxide enters the energy release heat exchanger 1522 to absorb heat to form high-temperature high-pressure carbon dioxide, the high-temperature high-pressure carbon dioxide enters the expander 1521 to expand and do work, the expander 1521 generates electricity, and the pressure and the temperature of the carbon dioxide flowing out of the expander 1521 are reduced and then flow into the gas storage 11. The generator can be connected with the power grid, so that the generator can provide electric energy for the power grid in the power utilization peak time period, and the power supply pressure of the power grid in the power utilization peak time period can be relieved. When the number of the expansion energy release parts 152 is plural, the plural energy release heat exchangers 1522 are alternately connected with the plural expansion machines 1521 in turn, and the inlet of the energy release heat exchanger 1522 at the start end is communicated with the evaporator 151, and the inlet of the gas storage 11 and the second gas passage are both communicated with the outlet of the expansion machine 1521 at the end. By providing a plurality of expanders 1521, the pressure potential energy stored in the carbon dioxide can be converted into electric energy as much as possible, thereby improving the energy storage efficiency of the energy storage system 100 and reducing the pressure energy waste of the carbon dioxide.

In some embodiments, referring to fig. 3, the carbon dioxide energy storage system 100 further includes a heat exchange assembly 21, where the heat exchange assembly 21 includes a cold storage tank 211 and a heat storage tank 212, heat exchange mediums are disposed in the cold storage tank 211 and the heat storage tank 212, and the cold storage tank 211 and the heat storage tank 212 form a heat exchange circuit (not numbered) between the energy storage circuit 13 and the energy release circuit 15, and the heat exchange mediums can flow in the heat exchange circuit. Specifically, the cold storage tank 211, the energy storage heat exchanger 1322, the heat storage tank 212 and the energy release heat exchanger 1522 are sequentially connected end to form a closed loop, thereby forming the heat exchange circuit described above. In the energy storage process of the carbon dioxide energy storage system 100, when the heat exchange medium flows through the energy storage heat exchanger 1322 from the cold storage tank 211, the heat in the energy storage heat exchanger 1322 is absorbed to form a high-temperature heat exchange medium, and then the heat exchange medium flows into the heat storage tank 212 to be stored, so that the energy generated when the carbon dioxide in the energy storage heat exchanger 1322 is compressed by the compressor 1321 is transferred into the heat exchange assembly 21. During the energy release process of the carbon dioxide energy storage system 100, the heat exchange medium flows into the energy release heat exchanger 1522 from the heat storage tank 212, so that the carbon dioxide flowing through the energy release heat exchanger 1522 can absorb the heat temporarily stored in the heat exchange medium in the heat exchange assembly 21, and then the heat exchange medium flows into the cold storage tank 211 for storage, thereby forming the circulation flow of the heat exchange medium in the heat exchange loop. In this embodiment, by arranging the cold storage tank 211 and the heat storage tank 212, and connecting the cold storage tank 211, the energy storage heat exchanger 1322, the heat storage tank 212 and the energy release heat exchanger 1522 end to end in sequence to form a heat exchange loop, when the heat exchange medium flows in the heat exchange loop, the heat of the compressed gaseous carbon dioxide in the energy storage heat exchanger 1322 can be transferred to the gaseous carbon dioxide in the energy release heat exchanger 1522, thereby fully utilizing the heat generated when compressing the carbon dioxide, and being beneficial to reducing the waste of energy.

The present invention provides a method for reducing carbon dioxide temperature float, which is applied to the carbon dioxide energy storage system 100, and includes,

when the temperature of the carbon dioxide in the gas storage 11 is lower than the first preset temperature, the gaseous carbon dioxide at normal temperature and normal pressure in the gas storage 11 can flow through the first gas pipeline 12 to absorb heat in the underground mine 200, raise temperature and then enter the energy storage loop 13, and the energy storage loop 13 compresses and condenses the carbon dioxide into liquid and stores the liquid in the liquid storage tank 14.

Specifically, taking the carbon dioxide energy storage system 100 as an example, a first gas pipeline 12 is arranged between the gas storage 11 and the energy storage loop 13, and a second gas pipeline 18 is arranged between the energy release loop 15 and the gas storage 11, when the temperature of carbon dioxide in the gas storage 11 is lower than a first preset temperature, the first valve 16 and the fourth valve 20 are opened, the second valve 17 and the third valve 19 are closed, so that the carbon dioxide can be heated up by absorbing heat in the underground mine 200 when passing through the first gas pipeline 12 and then enter the energy storage loop 13, and the carbon dioxide after expansion work from the energy release loop 15 can directly flow into the gas storage 11.

When the temperature of the carbon dioxide in the gas storage 11 is higher than the second preset temperature, the second valve 17 and the third valve 19 are opened, and the first valve 16 and the fourth valve 20 are closed, so that the carbon dioxide in the gas storage 11 directly enters the energy storage loop 13, and the carbon dioxide after expansion work from the energy release loop 15 can flow into the gas storage 11 after heat exchange cooling with the air in the underground mine 200 when passing through the second gas pipeline 18.

When the temperature of the carbon dioxide in the gas storage 11 is higher than or equal to the first preset temperature and lower than or equal to the second preset temperature, in the energy storage stage, the second valve 17 is opened to close the first valve 16, so that the carbon dioxide in the gas storage 11 directly enters the energy storage loop 13, in the energy release stage, the fourth valve 20 is opened and the third valve 19 is closed, and the carbon dioxide after expansion work from the energy release loop 15 directly flows into the gas storage 11.

In this embodiment, when the temperature of carbon dioxide in the gas storage 11 is lower than the first preset temperature in winter, the carbon dioxide flowing through the first gas pipeline 12 absorbs the heat of the air in the underground roadway 202 and then enters the compressor 1321 by opening the first valve 16, so that the temperature of the carbon dioxide is adapted to the rated working temperature of the compressor 1321, and when the temperature of the carbon dioxide in the gas storage 11 is higher than the second preset temperature in summer, the carbon dioxide flows through the second gas pipeline 18 and then flows into the gas storage 11 by opening the third valve 19, so that the temperature of the carbon dioxide is reduced to be adapted to the rated working temperature of the compressor 1321, thereby being beneficial to ensuring that the compressor 1321 can normally operate.

The present invention further provides a method for reducing the temperature drift of carbon dioxide, which is applied to the carbon dioxide energy storage system 100, and the method for reducing the temperature drift of carbon dioxide comprises,

when the temperature of the carbon dioxide in the gas storage is lower than a first preset temperature, the gaseous carbon dioxide at normal temperature and normal pressure in the gas storage can flow through a first gas pipeline, absorb heat in the underground mine, heat up and then enter the energy storage loop, and the energy storage loop compresses and condenses the carbon dioxide into liquid and stores the liquid in the liquid storage tank;

when the temperature of the carbon dioxide in the gas storage is higher than a second preset temperature, the carbon dioxide flowing out of the energy release loop can flow into the gas storage after heat exchange and cooling with air in the underground mine when passing through the second gas pipeline.

Referring to fig. 6, the carbon dioxide energy storage system 300 further includes: the gas storage 11, the energy storage loop 13, the liquid storage tank 14, the energy release loop 15 and the second gas pipeline 18. The gas storage 11 is used for storing carbon dioxide at normal temperature and normal pressure, at least part of the second gas pipeline 18 stretches into the underground mine 200, the outlet of the gas storage 11 is communicated with one end of the energy storage loop 13, the other end of the energy storage loop 13 is communicated with the inlet of the liquid storage tank 14, one end of the energy release loop 15 is communicated with the outlet of the liquid storage tank 14, one end of the second gas pipeline 18 is communicated with the other end of the energy release loop 15, and the other end of the second gas pipeline 18 is communicated with the inlet of the gas storage 11. The gaseous carbon dioxide at normal temperature and normal pressure in the gas storage 11 enters the energy storage loop 13, the energy storage loop 13 compresses and condenses the carbon dioxide into liquid, the liquid carbon dioxide in the liquid storage tank 14 is stored in the liquid storage tank 14, the liquid carbon dioxide in the liquid storage tank 14 expands to do work through the energy release loop 15, and the gaseous carbon dioxide after expansion work can flow through the second gas pipeline 18 to absorb the cold energy of the air in the underground mine, cool and flow into the gas storage 11 for storage. When the carbon dioxide flows through the second gas pipeline 18, the carbon dioxide can absorb the cold energy of the air in the underground mine 200, so that the carbon dioxide can flow into the gas storage 11 after being cooled, and the safety of the gas storage 11 is improved.

In some embodiments, the carbon dioxide energy storage system 300 further includes a third valve 19 and a fourth valve 20, the third valve 19 is disposed in the second gas pipeline 18, the fourth valve 20 is disposed between the energy release circuit 15 and the gas storage 11, and the fourth valve 20 is used to control communication or sealing between the energy release circuit 15 and the inlet of the gas storage 11. When the temperature of the carbon dioxide in the gas storage 11 is higher than the second preset temperature, the third valve 19 may be opened and the fourth valve 20 may be closed, and at this time, when the carbon dioxide expanded and acting from the energy release circuit 15 passes through the second gas pipeline 18, the air in the underground mine 200 absorbs the heat of the carbon dioxide flowing through the second gas pipeline 18 and flows into the gas storage 11, so that the temperature of the carbon dioxide in the gas storage 11 may be reduced to be matched with the rated working temperature of the compressor 1321 in the energy storage circuit 13. When the temperature of the carbon dioxide in the gas storage 11 is lower than or equal to the second preset temperature, the third valve 19 may be closed and the fourth valve 20 may be opened, at which time the carbon dioxide expanded from the energy release circuit 15 directly flows into the gas storage 11.

In this embodiment, when the temperature of the carbon dioxide in the gas storage 11 is higher than the second preset temperature, the third valve 19 is opened and the fourth valve 20 is closed, so that the carbon dioxide flows into the gas storage 11 after being cooled in the second gas pipeline 18, and the temperature of the carbon dioxide in the gas storage 11 can be reduced to the design temperature of the gas storage 11, thereby improving the safety of the gas storage 11.

The present invention also provides a second embodiment of a method for reducing carbon dioxide temperature drift, which is applied to the carbon dioxide energy storage system 300, and the method for reducing carbon dioxide temperature drift includes,

when the temperature of the carbon dioxide in the gas storage 11 is higher than the second preset temperature, the carbon dioxide expanded and acting from the energy release loop 15 can flow into the gas storage 11 after heat exchange and cooling with the air in the underground mine 200 when passing through the second gas pipeline 18.

Specifically, when the temperature of the carbon dioxide in the gas storage 11 is higher than the second preset temperature, the second valve 17 and the third valve 19 are opened, and the first valve 16 and the fourth valve 20 are closed, so that the carbon dioxide in the gas storage 11 directly enters the energy storage loop 13, and the carbon dioxide after expansion work from the energy release loop 15 can flow into the gas storage 11 after heat exchange with the air in the underground mine 200 and cooling when passing through the second gas pipeline 18.

In some embodiments, carbon dioxide energy storage system 300 further includes a temperature detector (not shown) mounted to gas storage 11 for detecting the temperature of carbon dioxide in gas storage 11.

In some embodiments, referring to fig. 7, the carbon dioxide energy storage system 300 further includes a first gas conduit 12, a first valve 16, and a second valve 17. At least part of the first gas pipeline 12 extends into the underground mine 200, one end of the first gas pipeline 12 is communicated with one end of the energy storage loop 13, and the other end of the first gas pipeline 12 is communicated with an outlet of the gas storage 11. By extending at least part of the first gas pipeline 12 into the underground mine 200, arranging the first valve 16 between the first gas pipeline 12 and the second valve 17 between the gas storage 11 and the energy storage circuit 13, when the first valve 16 is opened and the second valve 17 is closed, the gas storage 11, the first gas pipeline 12, the energy storage circuit 13, the liquid storage tank 14 and the energy release circuit 15 are sequentially connected to form a closed loop, carbon dioxide at normal temperature and normal pressure in the gas storage 11 absorbs heat in the underground mine 200 when flowing through the first gas pipeline 12 and then enters the energy storage circuit 13, the energy storage circuit 13 compresses and condenses the carbon dioxide into liquid state and stores the liquid carbon dioxide in the liquid storage tank 14, and the liquid carbon dioxide in the liquid storage tank 14 forms carbon dioxide at normal temperature and normal pressure after passing through the energy release circuit 15 and flows into the gas storage 11. In winter, the air temperature in the underground mine 200 is often higher than the temperature of the carbon dioxide in the air storage 11, so that the carbon dioxide is absorbed by the first gas pipeline 12 and enters the energy storage loop 13 after absorbing the heat in the underground mine 200, thereby raising the temperature of the carbon dioxide entering the energy storage loop 13, and facilitating the temperature of the carbon dioxide to reach the rated temperature of the compressor 1321 in the energy storage loop 13.

The foregoing description is only illustrative of the present invention and is not intended to limit the scope of the invention, and all equivalent structures or equivalent processes or direct or indirect application in other related technical fields are included in the scope of the present invention.

Claims

1. The carbon dioxide energy storage system is characterized by comprising a gas storage, an energy storage circuit, a liquid storage tank and an energy release circuit which are sequentially connected in a closed loop, and further comprising a first gas pipeline:

the gas storage is used for storing gaseous carbon dioxide at normal temperature and normal pressure;

one end of the first gas pipeline is communicated with an outlet of the gas storage, at least part of the first gas pipeline extends into the underground mine, and the other end of the first gas pipeline is communicated with one end of the energy storage loop;

the inlet of the liquid storage tank is communicated with the other end of the energy storage loop, one end of the energy release loop is communicated with the outlet of the liquid storage tank, and the other end of the energy release loop is communicated with the gas storage;

the gas carbon dioxide at normal temperature and normal pressure in the gas storage can absorb heat of air in the underground mine when flowing through the first gas pipeline, and then enter the energy storage loop after being heated, the energy storage loop compresses and condenses the carbon dioxide into liquid state and stores the liquid state in the liquid storage tank, and the liquid carbon dioxide in the liquid storage tank forms the gas carbon dioxide at normal temperature and normal pressure after being expanded and acting through the energy release loop and flows into the gas storage.

2. The carbon dioxide energy storage system of claim 1, wherein the carbon dioxide energy storage system comprises,

the carbon dioxide energy storage system further comprises a second gas pipeline, one end of the second gas pipeline is communicated with the other end of the energy release loop, the other end of the second gas pipeline is communicated with the inlet of the gas storage, at least part of the second gas pipeline stretches into the underground mine, and carbon dioxide flowing out of the energy release loop can flow into the gas storage after heat exchange cooling is carried out on the carbon dioxide flowing out of the energy release loop and air in the underground mine when passing through the second gas pipeline.

3. The carbon dioxide energy storage system of claim 2, wherein the carbon dioxide energy storage system comprises,

the underground mine comprises a shaft and an underground tunnel, the underground tunnel is communicated with the bottom of the shaft, the first gas pipeline at least partially penetrates through the shaft to extend into the underground tunnel, and the second gas pipeline at least partially penetrates through the shaft to extend into the underground tunnel.

4. The carbon dioxide energy storage system of claim 2, wherein the carbon dioxide energy storage system comprises,

the first gas pipeline is bent and extended in the underground mine; and/or the number of the groups of groups,

the second gas pipeline is bent and extended in the underground mine; and/or the number of the groups of groups,

The first gas pipeline is provided with a first booster fan; and/or the number of the groups of groups,

the second gas pipeline is provided with a second booster fan.

5. The carbon dioxide energy storage system of claim 2, wherein the carbon dioxide energy storage system comprises,

the energy storage loop comprises a condenser and at least one compression energy storage part, the compression energy storage part comprises a compressor and an energy storage heat exchanger, the compressor and the energy storage heat exchanger are alternately connected, the compressor at the starting end is communicated with the first gas pipeline, the energy storage heat exchanger at the tail end is communicated with the condenser, and the condenser is communicated with the liquid storage tank.

6. The carbon dioxide energy storage system of claim 5, wherein the carbon dioxide energy storage system comprises,

the energy storage loop further comprises a preheater, and the preheater is arranged between the compressor at the starting end and the first gas pipeline; and/or the number of the groups of groups,

the first gas pipeline is provided with a first heat exchanger; and/or

The second gas conduit is provided with a second heat exchanger.

7. The carbon dioxide energy storage system of claim 1, wherein the carbon dioxide energy storage system comprises,

the energy release loop comprises an evaporator and at least one expansion energy release part, the expansion energy release part comprises an expander and an energy release heat exchanger, the expander and the energy release heat exchanger are alternately connected, the evaporator is connected with the liquid storage tank, the evaporator is also connected with the energy release heat exchanger at the initial end, and the expander at the tail end is connected with the gas storage.

8. The carbon dioxide energy storage system of claim 2, wherein the carbon dioxide energy storage system comprises,

the first gas pipeline is provided with an inlet;

and/or the second gas conduit is provided with an inlet.

9. A carbon dioxide energy storage system is characterized in that,

the device comprises a gas storage, an energy storage loop, a liquid storage tank, an energy release loop and a second gas pipeline, wherein the gas storage, the energy storage loop, the liquid storage tank and the energy release loop are sequentially connected in a closed loop;

the gas storage is used for storing gaseous carbon dioxide at normal temperature and normal pressure, the outlet of the gas storage is communicated with one end of the energy storage loop, and the other end of the energy storage loop is communicated with the inlet of the liquid storage tank;

the outlet of the liquid storage tank is communicated with one end of the energy release loop, the other end of the energy release loop is communicated with one end of the second gas pipeline, at least part of the second gas pipeline stretches into an underground mine, and the other end of the second gas pipeline is communicated with the inlet of the gas storage;

the gas carbon dioxide at normal temperature and normal pressure in the gas storage enters the energy storage loop, the energy storage loop compresses and condenses the carbon dioxide into liquid state and stores the liquid carbon dioxide in the liquid storage tank, the liquid carbon dioxide in the liquid storage tank expands to do work through the energy release loop, and the expanded gas carbon dioxide can flow through the second gas pipeline to absorb the cold energy of air in an underground mine, cool and flow into the gas storage for storage.

10. A method for reducing the temperature drift of carbon dioxide, applied to a carbon dioxide energy storage system according to any one of claims 2-9,

and/or when the temperature of the carbon dioxide in the gas storage is higher than a second preset temperature, the carbon dioxide flowing out of the energy release loop can flow into the gas storage after heat exchange and cooling with the air in the underground mine when passing through the second gas pipeline.