Transcritical carbon dioxide energy storage system based on carbon dioxide capture and energy supplement

Abstract

The invention discloses a transcritical carbon dioxide energy storage system based on carbon dioxide capture and energy supplement. The transcritical carbon dioxide energy storage system comprises a transcritical carbon dioxide energy storage system and a carbon dioxide capture system, the transcritical carbon dioxide energy storage system comprises a depleted oil and gas reservoir gas storage unit, an energy storage unit, an energy release unit and a heat storage and waste heat utilization unit. The energy storage unit is used for compressing low-pressure carbon dioxide into a high-pressure state and storing the low-pressure carbon dioxide in the exhausted oil and gas reservoir gas storage unit; the energy release unit is used for applying work to generate power by using high-temperature and high-pressure carbon dioxide and injecting the carbon dioxide after acting into the depleted oil and gas reservoir gas storage unit; the heat storage and waste heat utilization unit is used for recovering compression heat in the transcritical carbon dioxide energy storage system and high-temperature waste heat in the carbon dioxide capture system; and the carbon dioxide capturing system is used for capturing carbon dioxide in the flue gas and injecting the captured carbon dioxide into the exhausted oil and gas reservoir gas storage unit. The system has the advantages of high cycle efficiency and good environmental benefits, and can solve the problems of greenhouse effect and energy shortage.

Description

Technical Field

[0001] The present invention relates to the technical fields of carbon dioxide capture and carbon dioxide energy storage, and particularly relates to a transcritical carbon dioxide energy storage system based on carbon dioxide capture and energy replenishment. Background Art

[0002] Existing power energy storage technologies include pumped-storage energy storage, compressed air energy storage, carbon dioxide energy storage, battery energy storage, flywheel energy storage, superconducting energy storage, and supercapacitor energy storage, etc. Due to the excellent advantages of supercritical carbon dioxide such as high density and good heat transfer performance, the transcritical carbon dioxide energy storage technology has become a physical energy storage technology with good prospects. At present, for transcritical carbon dioxide energy storage, due to the low heat storage temperature, the overall cycle efficiency of the system is low, resulting in more energy losses; meanwhile, there are pressure fluctuations during the process of releasing carbon dioxide from depleted oil and gas reservoirs, reducing the system stability and system performance.

[0003] Therefore, the present invention provides a transcritical carbon dioxide energy storage system based on carbon dioxide capture and energy replenishment to solve the above technical problems. Summary of the Invention

[0004] The purpose of the present invention is to provide a transcritical carbon dioxide energy storage system based on carbon dioxide capture and energy replenishment to solve the problems existing in the above prior art.

[0005] To achieve the above purpose, the present invention provides a transcritical carbon dioxide energy storage system based on carbon dioxide capture and energy replenishment, including a transcritical carbon dioxide energy storage system and a carbon dioxide capture system;

[0006] The transcritical carbon dioxide energy storage system includes:

[0007] A depleted oil and gas reservoir gas storage unit, which is used to store high-pressure and low-pressure carbon dioxide in the system;

[0008] An energy storage unit, which is used to compress low-pressure carbon dioxide to a high-pressure state and store it in the depleted oil and gas reservoir gas storage unit;

[0009] An energy release unit, which is used to generate electricity by using high-temperature and high-pressure carbon dioxide to do work and inject the carbon dioxide after doing work into the depleted oil and gas reservoir gas storage unit;

[0010] A heat storage and waste heat utilization unit, which is used to recover the compression heat in the transcritical carbon dioxide energy storage system and the high-temperature waste heat in the carbon dioxide capture system;

[0011] The carbon dioxide capture system is used to capture carbon dioxide in flue gas and inject the captured carbon dioxide into the depleted oil and gas reservoir gas storage unit.

[0012] Preferably, the depleted oil and gas reservoir gas storage unit includes a high-pressure injection well, a high-pressure production well, a low-pressure injection well, and a low-pressure production well. The high-pressure injection well is communicated with the high-pressure production well, and the low-pressure injection well is communicated with the low-pressure production well. The compressed carbon dioxide of the energy storage unit is stored in the depleted oil and gas reservoir through the high-pressure injection well. The carbon dioxide after the energy release unit performs work is injected into the depleted oil and gas reservoir through the low-pressure injection well. The carbon dioxide captured by the carbon dioxide capture system is injected into the depleted oil and gas reservoir through the high-pressure injection well and the low-pressure injection well respectively.

[0013] Preferably, the carbon dioxide capture system includes a carbon dioxide absorption tower, a rich / lean liquid heat exchanger, a desorption tower, a reboiler, a diverter, an amine solution / heat transfer oil heat exchanger, an amine solution storage tank, and a supplementary energy compressor. The liquid outlet end of the amine solution storage tank is communicated with the liquid inlet end of the carbon dioxide absorption tower. The liquid outlet end of the carbon dioxide absorption tower is communicated with the liquid inlet end of the desorption tower through the rich / lean liquid heat exchanger. The liquid outlet end of the desorption tower is communicated with a reboiler. The liquid outlet end of the reboiler is communicated with the liquid inlet end of the amine solution / heat transfer oil heat exchanger through the rich / lean liquid heat exchanger. The liquid outlet end of the amine solution / heat transfer oil heat exchanger is communicated with the amine solution storage tank. The gas outlet end of the reboiler is communicated with the desorption tower. The gas outlet end of the desorption tower is communicated with the gas inlet end of the diverter. The high-pressure gas outlet end of the diverter is communicated with the supplementary energy compressor. The gas outlet end of the supplementary energy compressor is communicated with the high-pressure injection well. The low-pressure gas outlet end of the diverter is communicated with the low-pressure injection well.

[0014] Preferably, the heat storage and waste heat utilization unit includes an intercooler, a reheater, a heat storage tank, and a cold storage tank. The heat storage tank is communicated with the cold storage tank through the reheater. The gas outlet end of the cold storage tank is communicated with the heat storage tank through the intercooler. The liquid outlet end of the cold storage tank is communicated with the heat storage tank through the amine solution / heat transfer oil heat exchanger.

[0015] Preferably, the energy storage unit includes a low-pressure compressor, a high-pressure compressor, and a cooler. The low-pressure production well is communicated with the gas inlet end of the cooler. A low-pressure throttle valve is arranged between the low-pressure production well and the cooler. The gas outlet end of the cooler is communicated with the low-pressure compressor. The outlet end of the low-pressure compressor is communicated with the high-pressure compressor through the intercooler. The outlet end of the high-pressure compressor is communicated with the high-pressure injection well.

[0016] Preferably, the energy release unit includes a high-pressure expander and a low-pressure expander; the high-pressure production well is communicated with the inlet end of the high-pressure expander, and a high-pressure throttle valve is arranged between the high-pressure production well and the high-pressure expander; the outlet end of the high-pressure expander is communicated with the low-pressure expander through the reheater, and the outlet end of the low-pressure expander is communicated with the low-pressure injection well.

[0017] Compared with the prior art, the present invention has the following advantages and technical effects:

[0018] The transcritical carbon dioxide energy storage system based on carbon dioxide capture and energy replenishment provided by the present invention injects the captured carbon dioxide into depleted oil and gas reservoirs to supplement formation energy, maintain formation pressure, ensure constant pressure of carbon dioxide at the outlets of high-pressure production wells and low-pressure production wells, improve system stability, and improve system cycle efficiency; at the same time, the use of high-temperature waste heat increases the heat storage temperature, thereby increasing the work capacity of carbon dioxide, and having advantages such as high cycle efficiency and good environmental benefits. Moreover, it helps to solve the problems of the greenhouse effect and energy shortage. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention, and for those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0020] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0021] In the figure: 1, low-pressure compressor; 2, high-pressure compressor; 3, high-pressure expander; 4, low-pressure expander; 5, intercooler; 6, reheater; 7, cold storage tank; 8, heat storage tank; 9, high-pressure injection well; 10, high-pressure production well; 11, low-pressure injection well; 12, low-pressure production well; 13, low-pressure throttle valve; 14, cooler; 15, high-pressure throttle valve; 16, carbon dioxide absorption tower; 17, rich and lean liquid heat exchanger; 18, desorption tower; 19, reboiler; 20, diverter; 21, amine solution / heat transfer oil heat exchanger; 22, amine solution storage tank; 23, energy replenishment compressor. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention. The following will refer to the drawings and combine the embodiments to detail the present invention.

[0023] As Figure 1 shown, the present invention provides a transcritical carbon dioxide energy storage system based on carbon dioxide capture and energy replenishment, including a transcritical carbon dioxide energy storage system and a carbon dioxide capture system;

[0024] The transcritical carbon dioxide energy storage system includes:

[0025] An exhausted oil and gas reservoir gas storage unit, which is used to store high-pressure and low-pressure carbon dioxide in the system;

[0026] An energy storage unit, which is used to compress low-pressure carbon dioxide into a high-pressure state and store it in the exhausted oil and gas reservoir gas storage unit;

[0027] An energy release unit, which is used to generate electricity by using high-temperature and high-pressure carbon dioxide to do work, and inject the carbon dioxide after doing work into the exhausted oil and gas reservoir gas storage unit;

[0028] A heat storage and waste heat utilization unit, which is used to recover the compression heat in the transcritical carbon dioxide energy storage system and the high-temperature waste heat in the carbon dioxide capture system;

[0029] The carbon dioxide capture system is used to capture carbon dioxide in flue gas and inject the captured carbon dioxide into the exhausted oil and gas reservoir gas storage unit.

[0030] The present invention makes full use of the carbon dioxide captured by the carbon dioxide capture system and the waste heat of the system, injects the captured carbon dioxide into the exhausted oil and gas reservoir, replenishes the formation energy, maintains the formation pressure, and ensures the constant pressure of carbon dioxide at the outlets of the high-pressure production well 10 and the low-pressure production well 12; at the same time, uses the high-temperature waste heat to increase the heat storage temperature, thereby improving the work capacity of carbon dioxide, and has the advantages of high cycle efficiency and good environmental benefits, and is an effective way to solve the greenhouse effect and energy shortage.

[0031] In a further optimized solution, the exhausted oil and gas reservoir gas storage unit includes a high-pressure injection well 9, a high-pressure production well 10, a low-pressure injection well 11 and a low-pressure production well 12. The high-pressure injection well 9 is connected to the high-pressure production well 10, and the low-pressure injection well 11 is connected to the low-pressure production well 12; the carbon dioxide compressed by the energy storage unit is stored in the exhausted oil and gas reservoir through the high-pressure injection well 9; the carbon dioxide after doing work by the energy release unit is injected into the exhausted oil and gas reservoir through the low-pressure injection well 11; the carbon dioxide captured by the carbon dioxide capture system is injected into the exhausted oil and gas reservoir through the high-pressure injection well 9 and the low-pressure injection well 11 respectively.

[0032] For a further optimized solution, the carbon dioxide capture system includes a carbon dioxide absorption tower 16, a rich / lean liquid heat exchanger 17, a desorption tower 18, a reboiler 19, a diverter 20, an amine solution / heat transfer oil heat exchanger 21, an amine solution storage tank 22, and an energy replenishment compressor 23; the liquid outlet end of the amine solution storage tank 22 is communicated with the liquid inlet end of the carbon dioxide absorption tower 16, the liquid outlet end of the carbon dioxide absorption tower 16 is communicated with the liquid inlet end of the desorption tower 18 through the rich / lean liquid heat exchanger 17, the liquid outlet end of the desorption tower 18 is communicated with a reboiler 19, the liquid outlet end of the reboiler 19 is communicated with the liquid inlet end of the amine solution / heat transfer oil heat exchanger 21 through the rich / lean liquid heat exchanger 17, and the liquid outlet end of the amine solution / heat transfer oil heat exchanger 21 is communicated with the amine solution storage tank 22; the gas outlet end of the reboiler 19 is communicated with the desorption tower 18, the gas outlet end of the desorption tower 18 is communicated with the gas inlet end of the diverter 20, the high-pressure gas outlet end of the diverter 20 is communicated with the energy replenishment compressor 23, the gas outlet end of the energy replenishment compressor 23 is communicated with the high-pressure injection well 9, and the low-pressure gas outlet end of the diverter 20 is communicated with the low-pressure injection well 11.

[0033] For a further optimized solution, the heat storage and waste heat utilization unit includes an intercooler 5, a reheater 6, a heat storage tank 8, and a cold storage tank 7; the heat storage tank 8 is communicated with the cold storage tank 7 through the reheater 6, the gas outlet end of the cold storage tank 7 is communicated with the heat storage tank 8 through the intercooler 5, and the liquid outlet end of the cold storage tank 7 is communicated with the heat storage tank 8 through the amine solution / heat transfer oil heat exchanger 21.

[0034] For a further optimized solution, the energy storage unit includes a low-pressure compressor 1, a high-pressure compressor 2, and a cooler 14; the low-pressure production well 12 is communicated with the gas inlet end of the cooler 14, and a low-pressure throttle valve 13 is arranged between the low-pressure production well 12 and the cooler 14; the gas outlet end of the cooler 14 is communicated with the low-pressure compressor 1, the outlet end of the low-pressure compressor 1 is communicated with the high-pressure compressor 2 through the intercooler 5, and the outlet end of the high-pressure compressor 2 is communicated with the high-pressure injection well 9.

[0035] For a further optimized solution, the energy release unit includes a high-pressure expander 3 and a low-pressure expander 4; the high-pressure production well 10 is communicated with the inlet end of the high-pressure expander 3, and a high-pressure throttle valve 15 is arranged between the high-pressure production well 10 and the high-pressure expander 3; the outlet end of the high-pressure expander 3 is communicated with the low-pressure expander 4 through the reheater 6, and the outlet end of the low-pressure expander 4 is communicated with the low-pressure injection well 11.

[0036] The working principle of the transcritical carbon dioxide energy storage system based on carbon dioxide capture and energy replenishment provided by the present invention:

[0037] The industrial carbon dioxide flue gas after denitrification and desulfurization is transported to the bottom of the carbon dioxide absorption tower 16. The flue gas at the bottom contacts countercurrently with the lean amine solution (the amine solution that has not absorbed carbon dioxide is called the lean solution) flowing down from the top of the tower to achieve the absorption of carbon dioxide. Among them, the flue gas from which carbon dioxide has been removed is discharged from the top of the carbon dioxide absorption tower 16; the rich amine solution is sent to the desorption tower 18 for desorption and regeneration treatment after heat exchange in the rich / lean solution heat exchanger 17 (the operating temperature of the carbon dioxide absorption tower 16 is lower than that of the desorption tower 18, so it needs to be heated by the rich / lean solution heat exchanger 17). In the desorption process, the rich solution is decomposed by the action of steam heating in the desorption tower 18, and the amine and carbon dioxide are regenerated. At this time, part of the amine solution that has not absorbed carbon dioxide is discharged from the bottom of the tower and enters the reboiler 19 for heating again to completely desorb carbon dioxide. The desorbed carbon dioxide enters the desorption tower 18 and is discharged from the top of the tower. After being split by the splitter 20, it is directly injected into the depleted oil and gas reservoir by the low-pressure injection well 11 or is injected into the high-pressure injection well 9 after being pressurized by the energy supplement compressor 23; the desorbed amine solution is then passed through the rich / lean solution heat exchanger 17 and the amine solution / heat transfer oil heat exchanger 21 (it can also be an amine solution / cooling water heat exchanger, or other heat storage media) to be cooled to a temperature equivalent to that of the flue gas and then stored in the amine solution storage tank 22 for recovery and reused the next time the capture system operates.

[0038] When the transcritical carbon dioxide energy storage system operates, it is divided into the energy storage and energy release processes.

[0039] During the low grid load period, the low-pressure production well 12 releases low-pressure carbon dioxide. After being depressurized by the low-pressure throttle valve 13 and cooled by the cooler 14, the low-pressure carbon dioxide is compressed by the low-pressure compressor 1 and the high-pressure compressor 2 driven by the surplus electric energy of the grid. During this period, the intercooler 5 recovers the compression heat during the compression process and stores it in the heat storage tank 8. The heat storage medium can use media such as heat transfer oil and cooling water. The compressed high-pressure carbon dioxide is injected into the depleted oil and gas reservoir through the high-pressure injection well 9, which is the energy storage process;

[0040] During the high grid load period, the energy release process is carried out. The cooling medium in the cold storage tank 7 enters the amine solution / heat transfer oil heat exchanger 21, is heated and then stored in the heat storage tank 8 to further increase the heat storage temperature of the system. The high-pressure carbon dioxide in the high-pressure production well 10 is released. After the pressure is stabilized by the high-pressure throttle valve 15, it enters the high-pressure expander 3 and the low-pressure expander 4 to do work. During this period, the reheater 6 makes full use of the compression heat recovered during the compression stage and the high-temperature waste heat generated by the carbon dioxide capture system to improve the work capacity of carbon dioxide. The carbon dioxide after doing work is injected into the depleted oil and gas reservoir through the low-pressure injection well 11 for storage and reused the next time the cycle is carried out, completing the energy release process.

[0041] In addition, during the energy storage process of the transcritical carbon dioxide energy storage system, the carbon dioxide captured by the carbon dioxide capture system is directly injected into the depleted oil and gas reservoir through the low-pressure injection well 11 to maintain the pressure stability of the depleted oil and gas reservoir during the energy storage process; during the energy release process of the transcritical carbon dioxide energy storage system, the carbon dioxide captured by the carbon dioxide capture system is pressurized by the energy replenishment compressor 23 and then injected into the depleted oil and gas reservoir through the high-pressure injection well 9 to maintain the pressure stability of the depleted oil and gas reservoir during the energy release process.

[0042] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention.

Claims

1. A transcritical carbon dioxide energy storage system based on carbon dioxide capture and energy replenishment, characterized in that: Including transcritical CO2 energy storage system and CO2 capture system; The transcritical carbon dioxide energy storage system comprises: A depleted oil and gas reservoir gas storage unit, wherein the depleted oil and gas reservoir gas storage unit is used to store high-pressure and low-pressure carbon dioxide in the system; An energy storage unit, the energy storage unit is used to compress low-pressure carbon dioxide into a high-pressure state and store it in the depleted oil and gas reservoir gas storage unit; An energy release unit, the energy release unit is used to generate electricity by using high-temperature and high-pressure carbon dioxide, and inject the carbon dioxide after the work into the gas storage unit of the depleted oil and gas reservoir; A heat storage and waste heat utilization unit, which is used to recover compression heat in the transcritical carbon dioxide energy storage system and high-temperature waste heat in the carbon dioxide capture system; The carbon dioxide capture system is used to capture carbon dioxide in flue gas and inject the captured carbon dioxide into the depleted oil and gas reservoir gas storage unit.

2. The transcritical carbon dioxide energy storage system based on carbon dioxide capture and energy replenishment according to claim 1 is characterized in that: The depleted oil and gas reservoir gas storage unit comprises a high-pressure injection well (9), a high-pressure recovery well (10), a low-pressure injection well (11) and a low-pressure recovery well (12); the high-pressure injection well (9) is connected to the high-pressure recovery well (10), and the low-pressure injection well (11) is connected to the low-pressure recovery well (12); the carbon dioxide compressed by the energy storage unit is stored in the depleted oil and gas reservoir through the high-pressure injection well (9); the carbon dioxide after work done by the energy release unit is injected into the depleted oil and gas reservoir through the low-pressure injection well (11); the carbon dioxide captured by the carbon dioxide capture system is injected into the depleted oil and gas reservoir through the high-pressure injection well (9) and the low-pressure injection well (11), respectively.

3. The transcritical carbon dioxide energy storage system based on carbon dioxide capture and energy replenishment according to claim 2 is characterized in that: The carbon dioxide capture system comprises a carbon dioxide absorption tower (16), a lean-rich liquid heat exchanger (17), a desorption tower (18), a reboiler (19), a flow divider (20), an alcohol amine solution / heat transfer oil heat exchanger (21), an alcohol amine solution storage tank (22) and an energy replenishment compressor (23); the liquid outlet of the alcohol amine solution storage tank (22) is connected to the liquid inlet of the carbon dioxide absorption tower (16), the liquid outlet of the carbon dioxide absorption tower (16) is connected to the liquid inlet of the desorption tower (18) through the lean-rich liquid heat exchanger (17), the liquid outlet of the desorption tower (18) is connected to the reboiler (19), and the liquid outlet of the reboiler (19) is connected to the reboiler (19). The lean-rich liquid heat exchanger (17) is connected to the liquid inlet of the alcoholamine solution / heat transfer oil heat exchanger (21), and the liquid outlet of the alcoholamine solution / heat transfer oil heat exchanger (21) is connected to the alcoholamine solution storage tank (22); the gas outlet of the reboiler (19) is connected to the desorption tower (18), the gas outlet of the desorption tower (18) is connected to the gas inlet of the splitter (20), the high-pressure gas outlet of the splitter (20) is connected to the energy replenishment compressor (23), the gas outlet of the energy replenishment compressor (23) is connected to the high-pressure injection well (9), and the low-pressure gas outlet of the splitter (20) is connected to the low-pressure injection well (11).

4. The transcritical carbon dioxide energy storage system based on carbon dioxide capture and energy replenishment according to claim 3 is characterized in that: The heat storage and waste heat utilization unit comprises an intercooler (5), a reheater (6), a heat storage tank (8) and a cold storage tank (7); the heat storage tank (8) is connected to the cold storage tank (7) via the reheater (6), the gas outlet of the cold storage tank (7) is connected to the heat storage tank (8) via the intercooler (5), and the liquid outlet of the cold storage tank (7) is connected to the heat storage tank (8) via the alcohol amine solution / heat transfer oil heat exchanger (21).

5. The transcritical carbon dioxide energy storage system based on carbon dioxide capture and energy replenishment according to claim 4 is characterized in that: The energy storage unit comprises a low-pressure compressor (1), a high-pressure compressor (2) and a cooler (14); the low-pressure recovery well (12) is connected to the air inlet end of the cooler (14), and a low-pressure throttle valve (13) is provided between the low-pressure recovery well (12) and the cooler (14); the air outlet end of the cooler (14) is connected to the low-pressure compressor (1), the outlet end of the low-pressure compressor (1) is connected to the high-pressure compressor (2) through the intercooler (5), and the outlet end of the high-pressure compressor (2) is connected to the high-pressure injection well (9).

6. The transcritical carbon dioxide energy storage system based on carbon dioxide capture and energy replenishment according to claim 4 is characterized in that: The energy release unit comprises a high-pressure expander (3) and a low-pressure expander (4); the high-pressure recovery well (10) is connected to the inlet end of the high-pressure expander (3), and a high-pressure throttle valve (15) is provided between the high-pressure recovery well (10) and the high-pressure expander (3); the outlet end of the high-pressure expander (3) is connected to the low-pressure expander (4) through the reheater (6), and the outlet end of the low-pressure expander (4) is connected to the low-pressure injection well (11).

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