Carbon sequestration coupled liquid co2 energy storage system

Abstract

The application provides a carbon sequestration coupled liquid carbon dioxide energy storage system, and belongs to the technical field of environment and energy, and comprises: a carbon capture device; a carbon sequestration module connected with the outlet of the carbon capture device; an energy storage module, the inlet of which is connected with the outlet of the carbon sequestration module; a first heat exchange module, the inlet of which is connected with the outlet of the energy storage module; a liquid CO2 storage module, the inlet of which is connected with the outlet of the first heat exchange module; a CO2 regenerative heat exchanger, the inlet of a cold fluid passage of the CO2 regenerative heat exchanger is connected with the outlet of the liquid CO2 storage module through the first heat exchange module; an energy release module, the inlet of which is connected with the outlet of the cold fluid passage of the CO2 regenerative heat exchanger, and the outlet of which is connected with the inlet of a hot fluid passage of the CO2 regenerative heat exchanger; and a carbon sequestration space, the inlet of which is connected with the outlet of the hot fluid passage of the CO2 regenerative heat exchanger and the outlet of the carbon sequestration module respectively. The application improves the energy storage efficiency and reduces the energy storage cost.

Description

Technical Field

[0001] This application relates to the fields of environmental and energy technology, and in particular to a carbon sequestration coupled liquid carbon dioxide energy storage system. Background Technology

[0002] With the continuous development of society and the economy, human consumption of energy for production and daily life is constantly increasing. Fossil fuels still account for a large proportion of the current energy utilization system, leading to massive CO2 emissions and a continuous rise in atmospheric CO2 levels. This has triggered numerous environmental and climate problems, directly manifested as the greenhouse effect, and has seriously impacted human life and survival. How to reduce carbon emissions during the utilization of fossil fuels is a technological problem that countries around the world urgently need to develop. Carbon capture and storage (CCS) directly separates CO2 from the fossil fuel utilization process (including before and after combustion) and compresses it to a supercritical high-pressure state, transporting it to geological environments such as underground aquifers. By utilizing the high pressure and sealed geological conditions, CO2 is stored for a long period of time, thereby directly and effectively achieving carbon emission reduction.

[0003] Replacing fossil fuels with renewable energy sources such as solar and wind power is an effective way to solve current energy and environmental problems. However, the volatility and intermittency of renewable energy lead to poor power quality. When power generation is too low or too high, the inability of modular power modules to connect to the grid causes energy waste such as wind and solar curtailment, reducing the actual utilization efficiency of renewable energy. To solve this problem, large-scale energy storage systems are needed to absorb the power that cannot be connected to the grid. These systems can also serve as an effective means of peak shaving and valley filling, improving the safety and stability of the power grid. Compressed air energy storage technology is currently at the forefront of research and application for large-scale physical energy storage, featuring long service life, high power generation efficiency, and good economic benefits.

[0004] Compared with air, carbon dioxide has better physical properties, such as a more easily achievable critical point (critical temperature close to room temperature and moderate critical pressure), low viscosity, high density, and good flow and heat transfer performance. Therefore, using supercritical CO2 to replace compressed air as an energy storage medium can effectively improve energy storage efficiency and has good development prospects.

[0005] Both carbon sequestration and carbon dioxide energy storage use CO2 as the working medium and have matching operating parameters. Combining the two has the potential to improve overall performance. Currently, existing work mainly focuses on studying carbon sequestration and carbon dioxide energy storage separately, and coupled research on the two is still relatively rare. Summary of the Invention

[0006] In view of this, embodiments of this application provide a carbon-encapsulated coupled liquid carbon dioxide energy storage system, which at least partially solves the problems of high supercritical CO2 storage pressure, low energy density and high energy storage cost in existing carbon dioxide energy storage systems.

[0007] This application provides a carbon sequestration coupled liquid carbon dioxide energy storage system, the system comprising:

[0008] A carbon capture device is used to process carbon-containing gas from an external module to obtain carbon dioxide gas.

[0009] A carbon sequestration module, which is connected to the outlet of the carbon capture device, is used to compress carbon dioxide gas;

[0010] An energy storage module, wherein the inlet of the energy storage module is connected to the outlet of the carbon sequestration module;

[0011] The first heat exchange module has its inlet connected to the outlet of the energy storage module;

[0012] A liquid CO2 storage module, wherein the inlet of the liquid CO2 storage module is connected to the outlet of the first heat exchange module;

[0013] The CO2 regenerative heat exchanger includes a cold fluid channel and a hot fluid channel. The inlet of the cold fluid channel of the CO2 regenerative heat exchanger is connected to the outlet of the liquid CO2 storage module through the first heat exchange module.

[0014] An energy release module, the inlet of which is connected to the outlet of the cold fluid channel of the CO2 regenerative heat exchanger, and the outlet of which is connected to the inlet of the hot fluid channel of the CO2 regenerative heat exchanger.

[0015] The carbon sequestration space has its inlet connected to the outlet of the hot fluid channel of the CO2 regenerative heat exchanger and the outlet of the carbon sequestration module.

[0016] According to a specific implementation of an embodiment of this application, the first heat exchange module includes a cold release heat exchanger, a cold storage heat exchanger, a cold-state cold storage working fluid tank, a hot-state cold storage working fluid tank, a cold release circulation pump, and a cold storage circulation pump. The cold release heat exchanger includes a hot fluid channel and a first cold fluid channel, and the cold storage heat exchanger includes a hot fluid channel and a cold fluid channel. The outlet of the cold-state cold storage working fluid tank, the cold release circulation pump, the first cold fluid channel of the cold release heat exchanger, and the inlet of the hot-state cold storage working fluid tank are sequentially connected to form a channel for releasing the cold energy of the cold storage working fluid during the CO2 liquefaction process. The inlet, the cold storage circulation pump, the hot fluid channel of the cold storage heat exchanger, and the inlet of the cold-state cold storage working fluid tank are connected in sequence to form a cold energy storage channel for the cold storage working fluid during the CO2 reheating expansion process; the inlet of the hot fluid channel of the cold release heat exchanger is connected to the outlet of the energy storage module, and the outlet of the hot fluid channel of the cold release heat exchanger is connected to the inlet of the liquid CO2 storage module; the inlet of the cold fluid channel of the cold storage heat exchanger is connected to the outlet of the liquid CO2 storage module, and the outlet of the cold fluid channel of the cold storage heat exchanger is connected to the inlet of the cold fluid channel of the CO2 regenerative heat exchanger.

[0017] According to a specific implementation of an embodiment of this application, the liquid CO2 storage module includes a liquid CO2 expander, a liquid CO2 storage tank, and a liquid CO2 pump connected in sequence. The inlet of the liquid CO2 expander is connected to the outlet of the hot fluid channel of the cold release heat exchanger, and the outlet of the liquid CO2 pump is connected to the inlet of the cold fluid channel of the cold storage heat exchanger.

[0018] According to a specific implementation of an embodiment of this application, the cooling heat exchanger further includes a second cold fluid channel. The inlet of the second cold fluid channel of the cooling heat exchanger is connected to the outlet of the liquid CO2 storage tank. The outlet of the second cold fluid channel of the cooling heat exchanger is connected to the inlet of the carbon sequestration module through an energy recovery expander, forming a liquefied CO2 gas phase reflux channel.

[0019] According to a specific implementation of an embodiment of this application, the energy storage module has at least one stage. The energy storage module includes an energy storage compressor and an energy storage cooler connected to each other. The energy storage cooler in each stage of the energy storage module is connected to the energy storage compressor in the adjacent stage of the energy storage module. The energy storage cooler in the initial stage of the energy storage module is connected to the outlet of the carbon capture device, and the energy storage cooler in the final stage of the energy storage module is connected to the inlet of the first heat exchange module.

[0020] According to a specific implementation of an embodiment of this application, the energy release module includes an energy release submodule and a second heat exchange module. The energy release submodule has at least one stage and includes an energy release expander and a heat release heat exchanger connected to each other. The heat release heat exchanger includes a cold fluid channel and a hot fluid channel. The inlet of the cold fluid channel of each stage of the heat release heat exchanger is connected to the outlet of the energy release expander of the adjacent stage. The outlet of the cold fluid channel of each stage of the heat release heat exchanger is connected to the inlet of the energy release expander of the same stage. The inlet of the cold fluid channel of the initial heat release heat exchanger is connected to the outlet of the cold fluid channel of the CO2 regenerative heat exchanger. The outlet of the final energy release expander is connected to the inlet of the hot fluid channel of the CO2 regenerative heat exchanger.

[0021] The inlet of the hot fluid channel of each stage of the heat release heat exchanger is connected to the outlet of the second heat exchange module, and the outlet of the hot fluid channel of each stage of the heat release heat exchanger is connected to the inlet of the second heat exchange module.

[0022] According to a specific implementation of an embodiment of this application, the second heat exchange module includes a cold-state thermal storage medium tank, a thermal storage circulation pump, an external heat supply module, and a hot-state thermal storage medium tank connected in sequence. The inlet of the cold-state thermal storage medium tank is connected to the outlet of the hot fluid channel of each stage of the heat release heat exchanger, and the outlet of the hot-state thermal storage medium tank is connected to the inlet of the hot fluid channel of each stage of the heat release heat exchanger.

[0023] According to one specific implementation of the present application, the outlet of the hot thermal storage tank is connected to the inlet of the hot fluid channel of each stage of the heat release heat exchanger via a heat release circulation pump.

[0024] According to a specific implementation of an embodiment of this application, the carbon sequestration module has at least one stage. The carbon sequestration module includes a carbon sequestration compressor and a carbon sequestration compressor cooler connected to each other. The carbon sequestration compressor cooler in each stage of the carbon sequestration module is connected to the carbon sequestration compressor in the adjacent stage of the carbon sequestration module. The carbon sequestration compressor in the initial carbon sequestration module is connected to the outlet of the carbon capture device, and the carbon sequestration compressor cooler in the final carbon sequestration module is connected to the inlet of the carbon sequestration space and the inlet of the energy storage module, respectively.

[0025] According to a specific implementation of an embodiment of this application, the outlet of the carbon storage module is connected to the carbon storage space through a carbon storage control valve, and the outlet of the carbon storage module is connected to the inlet of the energy storage module through an energy storage control valve.

[0026] Beneficial effects

[0027] The carbon sequestration coupled liquid carbon dioxide energy storage system in this embodiment effectively combines carbon sequestration and carbon dioxide energy storage. Both use CO2 as the working medium and have matching operating parameters. The combination of the two improves the overall performance and effectively increases energy storage efficiency. Furthermore, by setting up a liquid carbon dioxide energy storage system, the problems of high storage pressure, low energy density, and high energy storage cost of supercritical CO2 are solved. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of a carbon sequestration coupled liquid carbon dioxide energy storage system according to an embodiment of the present invention;

[0030] Figure 2 This is a diagram showing the CO2 flow path under the carbon sequestration working mode according to an embodiment of the present invention;

[0031] Figure 3 This is a flow path diagram of CO2 and thermal storage medium under the working mode of energy storage (including carbon sequestration) according to an embodiment of the present invention;

[0032] Figure 4 This is a flow path diagram of CO2 and thermal storage medium under the energy release (including carbon sequestration) working mode according to an embodiment of the present invention.

[0033] In the diagram: 1. Carbon capture device; 2. Carbon sequestration module; 21-1, Stage 1 carbon sequestration compressor; 21-2, Stage 1 carbon sequestration compressor cooler; 22-1, Stage 2 carbon sequestration compressor; 22-2, Stage 2 carbon sequestration compressor cooler; 2K-1, Stage K carbon sequestration compressor; 2K-2, Stage K carbon sequestration compressor cooler; 3. Energy storage module; 31-1, Stage 1 energy storage compressor; 31-2, Stage 1 energy storage cooler; 32-1, Stage 2 energy storage compressor; 32-2, Stage 2 energy storage cooler; 3M-1, Stage M energy storage compressor; 3M-2, Stage M energy storage cooler; 41-1, Cooling heat exchanger; 41-2, Cooling heat exchanger; 42-1, Cold-state cooling medium tank; 42-2, Hot-state cooling medium tank; 43-1, Cooling circulation pump; 43 -2. Cold storage circulation pump; 44. Liquid CO2 expander; 45. Liquid CO2 storage tank; 46. Energy recovery expander; 47. Liquid CO2 pump; 5. CO2 regenerative heat exchanger; 6. Energy release submodule; 61-1. Stage 1 energy release expander; 61-2. Stage 1 heat release heat exchanger; 61-3. Stage 1 heat release circulation pump; 62-1. Stage 2 energy release expander; 62-2. Stage 2 heat release heat exchanger; 62-3. Stage 2 heat release circulation pump; 6N-1. Stage N energy release expander; 6N-2. Stage N heat release heat exchanger; 6N-3. Stage N heat release circulation pump; 7. Carbon sequestration space; 81. Cold thermal storage medium tank; 82. Hot thermal storage medium tank; 83. Thermal storage circulation pump; 9. External heat supply module; V1. Carbon sequestration control valve; V2. Energy storage control valve. Detailed Implementation

[0034] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0035] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are merely embodiments of one module of this application, not embodiments of the entire module. This application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0036] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this application, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using structures and / or functionalities other than one or more of the aspects set forth herein.

[0037] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. The drawings only show the components related to this application and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0038] Furthermore, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the described aspects can be practiced without these specific details.

[0039] This application provides a carbon sequestration coupled with liquid carbon dioxide energy storage system, which is described below with reference to... Figures 1 to 4 Provide a detailed description.

[0040] Reference Figure 1 The carbon sequestration coupled liquid carbon dioxide energy storage system of this embodiment mainly includes a carbon capture device 1, a carbon sequestration module 2, an energy storage module 3, a first heat exchange module, a liquid CO2 storage module, a CO2 regenerative heat exchanger 5, an energy release module, and a carbon sequestration space 7. The carbon capture device 1 is used to process carbon-containing gas from an external module to obtain carbon dioxide gas. The carbon capture device 1 is provided with an inlet, a first outlet, and a second outlet. The external carbon-containing mixed gas enters the carbon capture device 1 through the inlet. The decarbonized gas after CO2 removal is discharged through the second outlet of the carbon capture device 1 or enters the corresponding subsequent processing flow. The CO2 gas enters the carbon sequestration module 2 through the first outlet of the carbon capture device 1.

[0041] The carbon sequestration module 2 is connected to the first outlet of the carbon capture device 1 and is used to compress carbon dioxide gas to obtain high-pressure CO2 with carbon sequestration pressure conditions.

[0042] The inlet of the energy storage module 3 is connected to the outlet of the carbon storage module 2, which is used to further compress and cool the high-pressure CO2 output by the carbon storage module 2 to obtain high-pressure room-temperature CO2.

[0043] The inlet of the first heat exchange module is connected to the outlet of the energy storage module 3, and is used to cool and liquefy the high-pressure normal-temperature CO2 output by the energy storage module 3 to form liquid CO2.

[0044] The inlet of the liquid CO2 storage module is connected to the outlet of the first heat exchange module. The liquid CO2 storage module stores the formed liquid CO2. The first heat exchange module is also used to provide heat energy for the CO2 fluid flowing into the energy release module.

[0045] The CO2 regenerative heat exchanger 5 includes a cold fluid channel and a hot fluid channel. The inlet of the cold fluid channel of the CO2 regenerative heat exchanger 5 is connected to the outlet of the liquid CO2 storage module through the first heat exchange module.

[0046] The inlet of the energy release module is connected to the outlet of the cold fluid channel of the CO2 regenerative heat exchanger 5, and the outlet of the energy release module is connected to the inlet of the hot fluid channel of the CO2 regenerative heat exchanger 5. The energy release module is used to perform a heat release heat exchange heat supplement - energy release expansion process to complete the energy release of the entire energy release process.

[0047] The inlet of the carbon sequestration space 7 is respectively connected to the outlet of the hot fluid channel of the CO2 regenerative heat exchanger 5 and the outlet of the carbon sequestration module 2.

[0048] In one embodiment, the carbon sequestration module 2 has at least one stage. The carbon sequestration module 2 includes a connected carbon sequestration compressor and a carbon sequestration compressor cooler. The carbon sequestration compressor cooler in each stage of the carbon sequestration module 2 is connected to the carbon sequestration compressor in the adjacent stage of the carbon sequestration module 2. The carbon sequestration compressor in the starting carbon sequestration module 2 is connected to the outlet of the carbon capture device 1, and the carbon sequestration compressor cooler in the terminal carbon sequestration module 2 is respectively connected to the inlet of the carbon sequestration space 7 and the inlet of the energy storage module 3.

[0049] As Figure 1 shown, the carbon sequestration module 2 has K stages. The k (1≤k≤K) stage carbon sequestration compressor and the k stage carbon sequestration compressor cooler are both provided with inlets and outlets. The inlet of the first-stage carbon sequestration compressor 21-1 is connected to the first outlet of the carbon capture device 1. The outlet of the k stage carbon sequestration compressor is connected to the inlet of the k stage carbon sequestration compressor cooler. The outlet of the k (k<K) stage carbon sequestration cooler is connected to the inlet of the (k + 1) stage carbon sequestration compressor.

[0050] Further, the outlet of the carbon sequestration module 2 is connected to the carbon sequestration space 7 through the carbon sequestration control valve V1, and the outlet of the carbon sequestration module 2 is connected to the inlet of the energy storage module 3 through the energy storage control valve V2. Specifically, one outlet of the K-stage carbon sequestration compressor cooler 2K-2 is connected to the carbon sequestration space 7 through the carbon sequestration control valve V1, and the other outlet of the K-stage carbon sequestration compressor cooler 2K-2 is connected to the inlet of the energy storage module 3 through the energy storage control valve V2.

[0051] In one embodiment, the energy storage module 3 has at least one stage. The energy storage module 3 includes an energy storage compressor and an energy storage cooler connected to each other. The energy storage cooler in each stage of the energy storage module 3 is connected to the energy storage compressor in the adjacent stage of the energy storage module 3. The energy storage cooler at the beginning of the energy storage module 3 is connected to the outlet of the carbon capture device 1, and the energy storage cooler at the end of the energy storage module 3 is connected to the inlet of the first heat exchange module.

[0052] Specifically, the energy storage module 3 has M stages. The m (1 ≤ m ≤ M)-stage energy storage compressor and the m-stage energy storage cooler are both provided with inlets and outlets. The inlet of the first-stage energy storage compressor 31-1 is connected to the outlet of the energy storage control valve V2. The outlet of the m-stage energy storage compressor is connected to the inlet of the m-stage energy storage cooler. The outlet of the m (m < M)-stage energy storage cooler is connected to the inlet of the (m + 1)-stage energy storage compressor.

[0053] In one embodiment, the first heat exchange module includes a cold release heat exchanger 41-1, a cold storage heat exchanger 41-2, a cold-state cold storage working medium storage tank 42-1, a hot-state cold storage working medium storage tank 42-2, a cold release circulation pump 43-1, and a cold storage circulation pump 43-2. The cold release heat exchanger 41-1 includes a hot fluid channel and a first cold fluid channel. The cold storage heat exchanger 41-2 includes a hot fluid channel and a cold fluid channel. The outlet of the cold-state cold storage working medium storage tank 42-1, the cold release circulation pump 43-1, the first cold fluid channel of the cold release heat exchanger 41-1, and the inlet of the hot-state cold storage working medium storage tank 42-2 are sequentially connected to form a cold energy release channel of the cold storage working medium during the CO2 liquefaction process. The outlet of the hot-state cold storage working medium storage tank 42-2, the cold storage circulation pump 43-2, the hot fluid channel of the cold storage heat exchanger 41-2, and the inlet of the cold-state cold storage working medium storage tank 42-1 are sequentially connected to form a cold energy storage channel of the cold storage working medium during the CO2 rewarming and expansion process.

[0054] The inlet of the hot fluid channel of the heat release heat exchanger 41-1 is connected to the outlet of the energy storage module 3. Specifically, the inlet of the hot fluid channel of the heat release heat exchanger 41-1 is connected to the outlet of the M-level energy storage cooler 3M-2; the outlet of the hot fluid channel of the heat release heat exchanger 41-1 is connected to the inlet of the liquid CO2 storage module; the inlet of the cold fluid channel of the cold storage heat exchanger 41-2 is connected to the outlet of the liquid CO2 storage module, and the outlet of the cold fluid channel of the cold storage heat exchanger 41-2 is connected to the inlet of the cold fluid channel of the CO2 regenerative heat exchanger 5.

[0055] Furthermore, the liquid CO2 storage module includes a liquid CO2 expander 44, a liquid CO2 storage tank 45, and a liquid CO2 pump 47 connected in sequence. The inlet of the liquid CO2 expander 44 is connected to the outlet of the hot fluid channel of the cold release heat exchanger 41-1, and the outlet of the liquid CO2 pump 47 is connected to the inlet of the cold fluid channel of the cold storage heat exchanger 41-2. The hot fluid channel of the cold release heat exchanger 41-1, the liquid CO2 expander 44, and the inlet of the liquid CO2 storage tank 45 are connected in sequence to form a CO2 cooling, expansion, liquefaction, and storage channel; the first outlet of the liquid CO2 storage tank 45, the liquid CO2 pump 47, and the cold fluid channel of the cold storage heat exchanger 41-2 are connected in sequence to form a liquid CO2 pressurization and reheating expansion channel.

[0056] The cooling heat exchanger 41-1 also includes a second cold fluid channel. The inlet of the second cold fluid channel of the cooling heat exchanger 41-1 is connected to the second outlet of the liquid CO2 storage tank 45. The outlet of the second cold fluid channel of the cooling heat exchanger 41-1 is connected to the inlet of the carbon sequestration module 2 through the energy recovery expander 46, forming a liquefied CO2 gas phase reflux channel.

[0057] In one embodiment, the energy release module includes an energy release submodule 6 and a second heat exchange module. The energy release submodule 6 has at least one stage and includes an energy release expander and a heat release heat exchanger connected to each other. The heat release heat exchanger includes a cold fluid channel and a hot fluid channel. The inlet of the cold fluid channel of each stage of the heat release heat exchanger is connected to the outlet of the energy release expander of the adjacent stage, and the outlet of the cold fluid channel of each stage of the heat release heat exchanger is connected to the inlet of the energy release expander of the same stage. The inlet of the cold fluid channel of the initial heat release heat exchanger is connected to the outlet of the cold fluid channel of the CO2 regenerating heat exchanger 5, and the outlet of the final energy release expander is connected to the inlet of the hot fluid channel of the CO2 regenerating heat exchanger 5. The inlet of the hot fluid channel of each stage of the heat release heat exchanger is connected to the outlet of the second heat exchange module, and the outlet of the hot fluid channel of each stage of the heat release heat exchanger is connected to the inlet of the second heat exchange module.

[0058] Further, the second heat exchange module includes a cold-state heat storage working medium storage tank 81, a heat storage circulation pump 83, an external heat supply module 9, and a hot-state heat storage working medium storage tank 82 that are connected in sequence. The inlet of the cold-state heat storage working medium storage tank 81 is connected to the outlet of the hot fluid channel of each stage of the heat release heat exchanger, and the outlet of the hot-state heat storage working medium storage tank 82 is connected to the inlet of the hot fluid channel of each stage of the heat release heat exchanger, forming an external heat source heat storage channel. A heat release circulation pump is connected between the outlet of the hot-state heat storage working medium storage tank 82 and the inlet of the hot fluid channel of each stage of the heat release heat exchanger.

[0059] Referring to Figure 1 , the energy release sub-module 6 has N levels. The nth (1≤n≤N) level energy release expander and the nth level heat release circulation pump are both provided with inlets and outlets. The nth level heat release heat exchanger is provided with a hot fluid channel and a cold fluid channel, and both the hot fluid channel and the cold fluid channel are provided with inlets and outlets. The inlet of the cold fluid channel of the first level heat release heat exchanger 61-2 is connected to the outlet of the cold fluid channel of the CO2 regenerative heat exchanger 5; the outlet of the cold fluid channel of the nth level heat release heat exchanger is connected to the inlet of the nth level energy release expander, and the outlet of the nth (n<N) level energy release expander is connected to the inlet of the n+1th level heat release heat exchanger; the outlet of the nth level heat release circulation pump is connected to the inlet of the hot fluid channel of the nth level heat release heat exchanger, the inlets of the heat release circulation pumps of each level (61-3 to 6N-3) are connected to the outlet of the hot-state heat storage working medium storage tank 82, and the outlets of the hot fluid channels of the heat release heat exchangers of each level (61-2 to 6N-2) are connected to the inlet of the cold-state heat storage working medium storage tank 81.

[0060] The carbon sequestration coupled liquid carbon dioxide energy storage system provided by the embodiment of the present application is divided into three working modes, namely, the carbon sequestration working mode, the energy storage working mode, and the energy release working mode. The operating state of the carbon sequestration working mode depends on the carbon-containing raw material gas. As long as the carbon-containing gas is continuously supplied, the carbon sequestration mode continues to work regardless of whether it is in the energy storage or energy release mode working link. When there is excess electric energy to be stored, the system enters the energy storage working mode. In this mode, the low-pressure CO2 obtained through the carbon capture device 1 reaches the carbon sequestration pressure through a multi-stage carbon sequestration compression-cooling process. A part of the CO2 is directly sequestered, and the other part of the CO2 continues through the energy storage compression-cooling process to form high-pressure normal-temperature CO2, and then enters the cold storage module, where it is cooled and liquefied using the stored cold energy. The liquefied CO2 is stored in the liquid CO2 storage tank 45. When electric energy needs to be output externally, the system enters the energy release working mode. In this mode, the stored liquid CO2 is pressurized by the liquid CO2 pump 47 and then enters the cold storage module for reheating and expansion, while storing its own cold energy in the cold storage module. The reheated and expanded CO2 replenishes a part of the heat through the regenerator, and then performs work and generates electricity externally through a multi-stage heat supplement-expansion process. The expanded CO2 reaches the carbon sequestration pressure, and then is subjected to regenerative heat exchange before being sequestered. The above processes are described separately as follows:

[0061] (1) Carbon sequestration working mode

[0062] In the carbon sequestration operating mode, the system only starts the carbon sequestration compressors at each stage and the carbon sequestration compressor cooler. The carbon sequestration control valve V1 is in the open state, and the energy storage control valve V2 is in the closed state.

[0063] CO2 flow path under carbon sequestration operating mode is as follows Figure 2 As shown, carbon-containing gas (which may be CO2-containing tail gas discharged from industrial systems, CO2-containing mixed gas produced by coal gasification, etc.) enters carbon capture device 1. The decarbonized tail gas after CO2 removal is discharged into the air or enters the corresponding subsequent treatment stage. After CO2 is captured, it enters the carbon sequestration and compression stage. In the carbon sequestration compression stage, CO2 first enters the first-stage carbon sequestration compressor 21-1 to increase pressure and temperature. After being pressurized and heated, the CO2 is cooled to room temperature by the first-stage carbon sequestration compressor cooler 21-2. The cooled CO2 then undergoes a series of carbon sequestration compression and cooling processes from stage 2 to stage K. Taking stage k (2≤k≤K) as an example, the CO2 cooled by the stage k-1 carbon sequestration compressor cooler enters the stage k carbon sequestration compressor for pressurization and temperature increase. The pressurized and heated CO2 then enters the stage k carbon sequestration compressor cooler for cooling to room temperature. After the above multi-stage carbon sequestration compression-cooling process, high-pressure CO2 that meets the carbon sequestration pressure conditions is obtained, and then enters the carbon sequestration space 7 for sequestration through the carbon sequestration control valve V1.

[0064] (2) Energy storage working mode

[0065] In this mode, carbon sequestration and energy storage processes can be carried out simultaneously according to actual carbon sequestration needs. Both carbon sequestration control valve V1 and energy storage control valve V2 are in the flow state, and the CO2 flow distribution in the carbon sequestration path and energy storage path is controlled by the opening degree of the above valves.

[0066] The flow paths of CO2 and thermal storage medium in energy storage (including carbon sequestration) working mode are as follows: Figure 3As shown, at this time, the carbon capture device 1, the carbon storage compressors at each stage, and the carbon storage compressor cooler operate in the same manner as in the carbon storage mode. The high-pressure ambient temperature CO2 discharged from the K-stage carbon storage compressor cooler 2K-2 enters the carbon storage space 7 and the energy storage compression stage through the carbon storage control valve V1 and the energy storage control valve V2, respectively. In the energy storage compression stage, high-pressure ambient temperature CO2 enters the first-stage energy storage compressor 31-1 via energy storage control valve V2 to increase pressure and temperature. The pressurized and heated CO2 is then cooled to ambient temperature by the first-stage thermal storage cooler 31-2. The cooled CO2 then undergoes a series of energy storage compression and cooling processes from stage 2 to stage M. Taking the m-th stage (2≤m≤M) as an example, the CO2 cooled by the m-1-stage thermal storage cooler enters the m-stage energy storage compressor to increase pressure and temperature. The pressurized and heated CO2 is then cooled to ambient temperature by the m-stage energy storage cooler. After these multi-stage compression-cooling processes, high-pressure ambient temperature CO2 enters the cooling liquefaction process. During cooling liquefaction, the high-pressure ambient temperature CO2 discharged from the M-stage energy storage cooler 3M-2 enters the hot fluid channel of the cold release heat exchanger 41-1, where it exchanges heat with the cold storage medium from the cold storage tank 42-1, which is driven to the first cold fluid channel of the cold release heat exchanger 41-1 by the cold release circulation pump 43-1. CO2 is cooled to a low temperature, and the temperature of the cold-state cold storage medium rises to form a hot-state cold storage medium, which is then stored in the hot-state cold storage medium tank 42-2. The cooled, high-pressure, low-temperature CO2 enters the liquid CO2 expander 44 to depressurize, expand, and liquefy, and performs work externally, forming a low-pressure gas-liquid two-phase mixture, which enters the liquid CO2 storage tank 45. The liquid portion is stored in the tank, and the gaseous portion is drawn out from the top of the tank (because the triple point pressure of CO2 is higher than atmospheric pressure, the discharged CO2 vapor is in a low-temperature pressurized state). The gaseous portion first enters the second cold fluid channel of the cold release heat exchanger 41-1, providing some cold energy for the CO2 cooling and liquefaction process in the hot fluid channel of the cold release heat exchanger 41-1. Then it enters the energy recovery expander 46 to expand and perform work, recovering the pressure energy. The expanded and depressurized CO2 returns to the first-stage carbon sealing compressor 21-1, completing the energy storage process and simultaneously completing the cold energy release process of the cold-state cold storage medium.

[0067] (3) Energy release working mode

[0068] In this mode, carbon sequestration and energy release processes can be carried out simultaneously according to actual carbon sequestration needs. Carbon sequestration control valve V1 is in the open state, while energy storage control valve V2 is in the closed state.

[0069] The flow paths of CO2 and thermal storage medium under the energy release (including carbon sequestration) working mode are as follows: Figure 4As shown. At this time, the carbon capture device 1, the various stages of carbon sequestration compressors, and the carbon sequestration compressor cooler operate in the same manner as in carbon sequestration mode. Liquid CO2 in liquid CO2 storage tank 45 is drawn out by liquid CO2 pump 47 and pressurized to a high-pressure state; the high-pressure liquid CO2 enters the cold fluid channel of cold storage heat exchanger 41-2, and exchanges heat with the hot cold storage medium from hot cold storage working medium storage tank 42-2, which is driven to the hot fluid channel of cold storage heat exchanger 41-2 by cold storage circulation pump 43-2. ​​The CO2 temperature rises, forming supercritical CO2 after rewarming expansion. At the same time, the temperature of the hot cold storage working medium drops to form cold cold storage working medium, which enters the cold cold storage working medium storage tank 42-1 for storage. After reheating and expansion, the supercritical CO2 first enters the cold fluid channel of the CO2 regenerating heat exchanger 5, where it undergoes preheating heat exchange with the CO2 containing residual heat that has been discharged from the N-stage energy release expander 6N-1 and entered the hot fluid channel of the CO2 regenerating heat exchanger 5. The preheated CO2 then enters the cold fluid channel of the first-stage heat release heat exchanger 61-2, where it exchanges heat with the hot thermal storage medium from the hot thermal storage tank 82, which is driven to the first-stage heat release circulation pump 61-3. The CO2 itself is then reheated. Simultaneously, the temperature of the hot thermal storage medium decreases and flows to the cold thermal storage medium tank 81 for storage. The high-pressure CO2, after being reheated, enters the first-stage energy release expander 61-1 for expansion and work, reducing the CO2 pressure and temperature. The CO2 after the first-stage expansion then undergoes a 2-N stage heat release heat exchange and reheat-energy release expansion process. Taking the nth stage (2≤n≤N) as an example, the CO2 after the expansion, depressurization, and cooling of the n-1 stage enters the cold fluid channel of the nth stage heat release heat exchanger, where it meets the hot thermal storage medium from the tank 82 and is driven by the nth stage heat release circulation pump into the nth stage. The hot-state heat storage medium in the hot fluid channel of the heat release heat exchanger exchanges heat, and CO2 replenishes the heat and raises the temperature. At the same time, the temperature of the hot-state heat storage medium decreases and flows to the cold-state heat storage medium tank 81 for storage. The high-pressure CO2 after replenishment and raising of temperature enters the n-stage energy release expander to expand and do work. The CO2 discharged from the N-stage energy release expander 6N-1 reaches the carbon sequestration pressure and carries residual heat. Then it enters the hot fluid channel of the CO2 regenerating heat exchanger 5, releasing its own residual heat to the CO2 in the cold fluid channel of the CO2 regenerating heat exchanger 5. Finally, it enters the carbon sequestration space 7 for sequestration. Through the above multi-stage heat release heat exchange replenishment-energy release expansion process, the energy release of the entire energy release process is completed.

[0070] During this process, the hot thermal storage medium in the hot thermal storage tank 82 enters the heat release heat exchangers (stages 1-N) through various stages of heat release circulation pumps, releasing the stored heat to the CO2 before its energy release expansion. The temperature of the hot thermal storage medium decreases, forming a cold thermal storage medium, which then enters the cold thermal storage tank 81, completing the heat release process of the energy release process. Simultaneously, the high-pressure liquid CO2 releases its own cold energy during the rewarming expansion process and stores it in the cold storage medium.

[0071] In addition, the thermal storage process operates independently. At this time, the cold thermal storage medium in the cold thermal storage medium tank 81 is drawn out by the thermal storage circulation pump 83 and enters the external heat supply module 9. After being heated by the external heat source (which may be the heat generated by solar thermal collection, industrial waste heat, etc.), it forms a hot thermal storage medium and enters the hot thermal storage medium tank 82 for storage.

[0072] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A carbon sequestration coupled liquid carbon dioxide energy storage system, characterized in that, include: A carbon capture device is used to process carbon-containing gas from an external module to obtain carbon dioxide gas. The carbon sequestration module is connected to the outlet of the carbon capture device and is used to compress carbon dioxide gas. The energy storage module has its inlet connected to the outlet of the carbon sequestration module. The first heat exchange module has its inlet connected to the outlet of the energy storage module; A liquid CO2 storage module, the inlet of which is connected to the outlet of the first heat exchange module; The CO2 regenerative heat exchanger includes a cold fluid channel and a hot fluid channel. The inlet of the cold fluid channel of the CO2 regenerative heat exchanger is connected to the outlet of the liquid CO2 storage module through the first heat exchange module. The energy release module has its inlet connected to the outlet of the cold fluid channel of the CO2 regenerative heat exchanger, and its outlet connected to the inlet of the hot fluid channel of the CO2 regenerative heat exchanger. The carbon sequestration space has its inlet connected to the outlet of the hot fluid channel of the CO2 regenerative heat exchanger and the outlet of the carbon sequestration module, respectively. The first heat exchange module includes a cold release heat exchanger, a cold storage heat exchanger, a cold-state cold storage working fluid tank, a hot-state cold storage working fluid tank, a cold release circulation pump, and a cold storage circulation pump. The cold release heat exchanger includes a hot fluid channel and a first cold fluid channel, and the cold storage heat exchanger includes a hot fluid channel and a cold fluid channel. The outlet of the cold-state cold storage working fluid tank, the cold release circulation pump, the first cold fluid channel of the cold release heat exchanger, and the inlet of the hot-state cold storage working fluid tank are connected sequentially to form a channel for releasing the cold energy of the cold storage working fluid during the CO2 liquefaction process; the outlet of the hot-state cold storage working fluid tank and the cold storage circulation pump... The pump, the hot fluid channel of the cold storage heat exchanger, and the inlet of the cold storage working fluid tank are connected in sequence to form a cold energy storage channel for the working fluid during the CO2 reheating expansion process; the inlet of the hot fluid channel of the release heat exchanger is connected to the outlet of the energy storage module, and the outlet of the hot fluid channel of the release heat exchanger is connected to the inlet of the liquid CO2 storage module; the inlet of the cold fluid channel of the cold storage heat exchanger is connected to the outlet of the liquid CO2 storage module, and the outlet of the cold fluid channel of the cold storage heat exchanger is connected to the inlet of the cold fluid channel of the CO2 regenerative heat exchanger. The liquid CO2 storage module includes a liquid CO2 expander, a liquid CO2 storage tank, and a liquid CO2 pump connected in sequence. The inlet of the liquid CO2 expander is connected to the outlet of the hot fluid channel of the cold release heat exchanger, and the outlet of the liquid CO2 pump is connected to the inlet of the cold fluid channel of the cold storage heat exchanger. The cold release heat exchanger also includes a second cold fluid channel. The inlet of the second cold fluid channel of the cold release heat exchanger is connected to the outlet of the liquid CO2 storage tank, and the outlet of the second cold fluid channel of the cold release heat exchanger is connected to the inlet of the carbon sequestration module through the energy recovery expander, forming a liquefied CO2 gas phase reflux channel.

2. The carbon sequestration coupled liquid carbon dioxide energy storage system according to claim 1, characterized in that, The energy storage module has at least one stage, and the energy storage module includes an energy storage compressor and an energy storage cooler connected to each other. The energy storage cooler in each stage of the energy storage module is connected to the energy storage compressor in the adjacent stage of the energy storage module. The energy storage cooler in the initial stage of the energy storage module is connected to the outlet of the carbon capture device, and the energy storage cooler in the final stage of the energy storage module is connected to the inlet of the first heat exchange module.

3. The carbon sequestration coupled liquid carbon dioxide energy storage system according to claim 1, characterized in that, The energy release module includes an energy release submodule and a second heat exchange module. The energy release submodule has at least one stage and includes an energy release expander and a heat release heat exchanger connected to each other. The heat release heat exchanger includes a cold fluid channel and a hot fluid channel. The inlet of the cold fluid channel of each stage of the heat release heat exchanger is connected to the outlet of the energy release expander of the adjacent stage. The outlet of the cold fluid channel of each stage of the heat release heat exchanger is connected to the inlet of the energy release expander of the same stage. The inlet of the cold fluid channel of the initial heat release heat exchanger is connected to the outlet of the cold fluid channel of the CO2 regenerative heat exchanger. The outlet of the final energy release expander is connected to the inlet of the hot fluid channel of the CO2 regenerative heat exchanger. The inlet of the hot fluid channel of each stage of the heat release heat exchanger is connected to the outlet of the second heat exchange module, and the outlet of the hot fluid channel of each stage of the heat release heat exchanger is connected to the inlet of the second heat exchange module.

4. The carbon sequestration coupled liquid carbon dioxide energy storage system according to claim 3, characterized in that, The second heat exchange module includes a cold thermal storage medium tank, a thermal storage circulation pump, an external heat supply module, and a hot thermal storage medium tank connected in sequence. The inlet of the cold thermal storage medium tank is connected to the outlet of the hot fluid channel of each stage of the heat release heat exchanger, and the outlet of the hot thermal storage medium tank is connected to the inlet of the hot fluid channel of each stage of the heat release heat exchanger.

5. The carbon sequestration coupled liquid carbon dioxide energy storage system according to claim 4, characterized in that, The outlet of the hot thermal storage tank is connected to the inlet of the hot fluid channel of each stage of the heat release heat exchanger via a heat release circulation pump.

6. The carbon sequestration coupled liquid carbon dioxide energy storage system according to claim 1, characterized in that, The carbon sequestration module has at least one stage, and the carbon sequestration module includes a carbon sequestration compressor and a carbon sequestration compressor cooler connected to each other. The carbon sequestration compressor cooler in each stage of the carbon sequestration module is connected to the carbon sequestration compressor in the adjacent stage of the carbon sequestration module. The carbon sequestration compressor in the initial carbon sequestration module is connected to the outlet of the carbon capture device, and the carbon sequestration compressor cooler in the final carbon sequestration module is connected to the inlet of the carbon sequestration space and the inlet of the energy storage module, respectively.

7. The carbon sequestration coupled liquid carbon dioxide energy storage system according to any one of claims 1-6, characterized in that, The outlet of the carbon sequestration module is connected to the carbon sequestration space via a carbon sequestration control valve, and the outlet of the carbon sequestration module is connected to the inlet of the energy storage module via an energy storage control valve.

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