A transcritical carbon dioxide energy storage system based on energy compensation of gas storage

Abstract

The present application belongs to the field of carbon dioxide capture and energy storage technology, and particularly relates to a transcritical carbon dioxide energy storage system based on energy compensation of gas storage, comprising: a carbon dioxide capture system for capturing carbon dioxide in flue gas; a transcritical carbon dioxide energy storage system for carbon dioxide energy storage and energy release; a waste heat utilization system for absorbing heat during carbon dioxide compression and work and providing cold energy and heat energy for terminals respectively; the transcritical carbon dioxide energy storage system comprises an energy storage unit, an energy release unit, a depleted oil and gas reservoir high-pressure gas storage unit and a depleted oil and gas reservoir low-pressure gas storage unit. The present application uses geothermal heat in the depleted oil and gas reservoir to heat carbon dioxide, improves the work capacity of carbon dioxide, and improves the heat energy utilization rate of the carbon dioxide energy storage system. Through injection of the captured carbon dioxide into the low-pressure and high-pressure gas storage in the energy storage and energy release working modes, the pressure stability of the low-pressure and high-pressure gas storage is maintained, and the system performance is further improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of carbon dioxide capture and energy storage, and particularly relates to a transcritical carbon dioxide energy storage system based on energy compensation of gas storage. BACKGROUND

[0002] New energy power generation is ushering in a leapfrog development, and the installed capacity scale in the power system is also increasing, but it also brings new energy consumption difficulties, reduced rotational inertia, increased security risks, and the like.

[0003] As a flexible adjustment resource, energy storage can ensure the consumption of new energy, improve the flexibility of the power system, support the safe and stable operation of the new power system, and will also usher in explosive growth in the future. In the field of energy storage, pumped storage has always been the core of energy storage; however, considering the large construction investment, long construction period, and great site selection difficulty, compressed gas energy storage is just a supplement, and is considered as one of the new energy storage technologies with the most development potential.

[0004] At present, compressed gas energy storage mainly has two media: air and carbon dioxide. The compressed carbon dioxide energy storage system is proposed on the basis of the traditional compressed gas energy storage technology, and the use of carbon dioxide as the working medium of the compressed gas energy storage system is still in the stage of gradual development.

[0005] Through research on the prior art, it is found that the traditional carbon dioxide energy storage system has problems such as low heat energy utilization rate and unstable system operation (due to fluctuations in the pressure of the high-pressure and low-pressure gas storage outlet carbon dioxide during operation). SUMMARY

[0006] The purpose of the present application is to provide a transcritical carbon dioxide energy storage system based on energy compensation of gas storage, which uses depleted oil and gas reservoirs as gas storage to store high-pressure and low-pressure carbon dioxide, can make full use of existing resources, and can use the geothermal energy in the depleted oil and gas reservoirs to improve the heat energy utilization rate of the carbon dioxide energy storage system, thereby solving the above problems.

[0007] To achieve the above purpose, the present application provides the following scheme:

[0008] A transcritical carbon dioxide energy storage system based on energy compensation of gas storage, comprising:

[0009] A carbon dioxide capture system for capturing carbon dioxide in flue gas;

[0010] The transcritical carbon dioxide energy storage system comprises an energy storage mode and an energy release mode.

[0011] A waste heat utilization system for absorbing heat generated during carbon dioxide compression and work and providing cold energy and heat energy for terminals respectively;

[0012] The transcritical carbon dioxide energy storage system comprises an energy storage unit, an energy release unit, a depleted oil and gas reservoir high-pressure gas storage unit and a depleted oil and gas reservoir low-pressure gas storage unit in communication;

[0013] In the energy storage mode, the carbon dioxide capture system delivers carbon dioxide to the depleted oil and gas reservoir low-pressure gas storage unit, and the energy storage unit compresses carbon dioxide in the depleted oil and gas reservoir low-pressure gas storage unit to a high-pressure state and delivers it to the depleted oil and gas reservoir high-pressure gas storage unit;

[0014] In the energy release mode, the carbon dioxide capture system compresses carbon dioxide to a high-pressure state by a supplemental compressor and delivers it to the depleted oil and gas reservoir high-pressure gas storage unit, and the energy release unit releases high-pressure carbon dioxide in the depleted oil and gas reservoir high-pressure gas storage unit and generates power by work, and delivers carbon dioxide in a low-pressure state to the depleted oil and gas reservoir low-pressure gas storage unit.

[0015] Preferably, the depleted oil and gas reservoir high-pressure gas storage unit comprises a high-pressure injection well and a high-pressure recovery well, a first inlet of the high-pressure injection well is in communication with an outlet of the supplemental compressor, a second inlet of the high-pressure injection well is in communication with an outlet of the energy storage unit, an outlet of the high-pressure injection well is in communication with an inlet of a first depleted oil and gas reservoir storage space, an outlet of the first depleted oil and gas reservoir storage space is in communication with an inlet of the high-pressure recovery well, and an outlet of the high-pressure recovery well is in communication with an inlet of the energy release unit through a high-pressure throttling valve.

[0016] Preferably, the depleted oil and gas reservoir low-pressure gas storage unit comprises a low-pressure injection well and a low-pressure recovery well, a first inlet of the low-pressure injection well is in communication with one of the outlets of the carbon dioxide capture system, a second inlet of the low-pressure injection well is in communication with an outlet of the energy release unit, an outlet of the low-pressure injection well is in communication with an inlet of a second depleted oil and gas reservoir storage space, and an outlet of the second depleted oil and gas reservoir storage space is in communication with an inlet of the energy storage unit.

[0017] Preferably, the energy release unit comprises a high-pressure expander, a medium-pressure expander and a low-pressure expander arranged in sequence in communication;

[0018] The inlet of the high-pressure expander is in communication with the outlet of the high-pressure throttling valve;

[0019] The outlet of the low-pressure expander is in communication with the inlet of the low-pressure injection well;

[0020] The waste heat utilization system is used for inter-stage heating during movement of carbon dioxide in the high-pressure expander, the medium-pressure expander and the low-pressure expander and low-temperature waste heat utilization.

[0021] Preferably, the energy storage unit comprises a low-pressure compressor, a medium-pressure compressor and a high-pressure compressor arranged in sequence;

[0022] The inlet of the low-pressure compressor is communicated with the outlet of the low-pressure production well, and the outlet of the high-pressure compressor is communicated with the second inlet of the high-pressure injection well;

[0023] The waste heat utilization system is used for inter-stage heat absorption of carbon dioxide during movement of the low-pressure compressor, the medium-pressure compressor and the high-pressure compressor.

[0024] Preferably, the outlet of the low-pressure production well is communicated with the inlet of a low-pressure throttling valve, the outlet of the low-pressure throttling valve is communicated with the inlet of a cooler, and the outlet of the cooler is communicated with the inlet of the low-pressure compressor.

[0025] Preferably, the waste heat utilization system comprises a heat storage and high-temperature waste heat utilization unit and a low-temperature waste heat utilization unit;

[0026] The low-temperature waste heat utilization unit is used for utilizing low-temperature waste heat of the outlet of the low-pressure expander to generate additional energy;

[0027] The heat storage and high-temperature waste heat utilization unit is used for recovering compression heat of carbon dioxide compression process, improving efficiency of carbon dioxide work process, improving heat storage temperature by utilizing high-temperature waste heat generated by the carbon dioxide capture system, and supplying part of cold energy and heat energy to terminal use.

[0028] Preferably, the low-temperature waste heat utilization unit comprises an evaporator, a turbine, a condenser and a pump;

[0029] The heat source side inlet of the evaporator is communicated with the outlet of the low-pressure expander, the heat source side outlet of the evaporator is communicated with the inlet of the low-pressure injection well, the cold source side outlet of the evaporator is communicated with the inlet of the turbine, the outlet of the turbine is communicated with the heat source side inlet of the condenser, the heat source side outlet of the condenser is communicated with the inlet of the pump, and the outlet of the pump is communicated with the cold source side inlet of the evaporator;

[0030] The cold source side inlet of the condenser is used for inputting cold energy.

[0031] Preferably, the heat storage and high-temperature waste heat utilization unit comprises a cold storage tank, a heat storage tank, a first inter-stage reheater, a second inter-stage reheater, a first inter-stage cooler and a second inter-stage cooler;

[0032] The first inter-stage cooler is arranged between the low-pressure compressor and the medium-pressure compressor, and the second inter-stage cooler is arranged between the medium-pressure compressor and the high-pressure compressor;

[0033] The first inter-stage reheater is arranged in communication between the high-pressure expander and the medium-pressure expander, and the second inter-stage reheater is arranged in communication between the medium-pressure expander and the low-pressure expander;

[0034] The cold source side of the first inter-stage reheater, the second inter-stage reheater, the first inter-stage cooler and the second inter-stage cooler is in communication with the cold storage tank;

[0035] The heat source side of the first inter-stage reheater, the second inter-stage reheater, the first inter-stage cooler and the second inter-stage cooler is in communication with the heat storage tank;

[0036] In the energy storage mode, the cold storage tank releases cooling medium, absorbs the compression heat of the carbon dioxide compressed by the low-pressure compressor and the medium-pressure compressor through the first inter-stage cooler and the second inter-stage cooler, recovers and transports to the heat storage tank;

[0037] In the energy release mode, the heat storage tank releases heat energy, and the first inter-stage reheater and the second inter-stage reheater increase the temperature of the carbon dioxide after working in the high-pressure expander and the medium-pressure expander;

[0038] Part of the cold energy and part of the heat energy of the cold storage tank and the heat storage tank are used for terminal use;

[0039] The cold storage tank and the heat storage tank are used to recover the high-temperature waste heat generated by the carbon dioxide capture system.

[0040] Preferably, the carbon dioxide capture system comprises an absorption tower, a lean-rich liquid heat exchanger, a desorption tower, a reboiler, an alcohol amine solution / conductive oil heat exchanger and an alcohol amine solution storage tank;

[0041] The top inlet of the absorption tower is in communication with the outlet of the alcohol amine solution storage tank, the bottom outlet of the absorption tower is in communication with the cold source side inlet of the lean-rich liquid heat exchanger, the cold source side outlet of the lean-rich liquid heat exchanger is in communication with the top inlet of the desorption tower, the top outlet of the desorption tower is in communication with the inlet of the energy supplementing compressor and the inlet of the low-pressure injection well, respectively, the bottom outlet of the desorption tower is connected with the reboiler inlet, the top outlet of the reboiler is in communication with the bottom inlet of the desorption tower, the bottom outlet of the reboiler is in communication with the heat source side inlet of the lean-rich liquid heat exchanger, the heat source side outlet of the lean-rich liquid heat exchanger is in communication with the heat source side inlet of the alcohol amine solution / conductive oil heat exchanger, the heat source side outlet of the alcohol amine solution / conductive oil heat exchanger is in communication with the inlet of the alcohol amine solution storage tank, the cold source side inlet of the alcohol amine solution / conductive oil heat exchanger is in communication with the outlet of the cold storage tank, and the cold source side outlet of the alcohol amine solution / conductive oil heat exchanger is in communication with the inlet of the heat storage tank.

[0042] Compared with the prior art, the present application has the following advantages and technical effects:

[0043] 1. The present application uses depleted oil and gas reservoirs as gas storage to store high and low pressure carbon dioxide, solving the problem of large capacity gas storage required for carbon dioxide energy storage.

[0044] 2. The present application proposes a system that can use geothermal energy in the depleted oil and gas reservoir to heat carbon dioxide, improving the work capacity of carbon dioxide and improving the thermal energy utilization rate of the carbon dioxide energy storage system. At the same time, the recovered compression heat and cold energy in the heat storage tank and the cold storage tank can also be supplied to heat users and cold users, realizing cold-heat-electricity combined production, and the system has high energy utilization efficiency.

[0045] 3. The present application uses a carbon dioxide capture system to capture carbon dioxide, and injects the captured carbon dioxide into low and high pressure gas storage in energy storage and energy release modes, to maintain the pressure stability of the low and high pressure gas storage, and further improve the system performance.

[0046] 4. Since the present system uses depleted oil and gas reservoirs as gas storage, and can use geothermal energy to heat carbon dioxide, the heat of carbon dioxide after the low pressure expander can be further utilized. Therefore, the carbon dioxide energy storage system is coupled with a Rankine cycle to realize low temperature waste heat utilization, the heat of carbon dioxide after the low pressure expander is introduced into an evaporator to utilize the waste heat and generate electricity, improving the energy utilization rate of the system and outputting more electric energy. BRIEF DESCRIPTION OF DRAWINGS

[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor under the premise of not paying creative labor:

[0048] Figure 1 is a structural schematic diagram of the present application;

[0049] Wherein, 1, absorption tower; 2, lean rich liquid heat exchanger; 3, desorption tower; 4, reboiler; 5, alcohol amine solution / conduction oil heat exchanger; 6, alcohol amine solution storage tank; 7, energy supplementing compressor; 8, low pressure compressor; 9, medium pressure compressor; 10, high pressure compressor; 11, first interstage cooler; 12, second interstage cooler; 13, high pressure injection well; 14, high pressure production well; 15, high pressure throttle valve; 16, high pressure expander; 17, medium pressure expander; 18, low pressure expander; 19, first interstage reheater; 20, second interstage reheater; 21, low pressure injection well; 22, low pressure production well; 23, low pressure throttle valve; 24, cooler; 25, cold storage tank; 26, heat storage tank; 27, turbine; 28, condenser; 29, pump; 30, evaporator. DETAILED DESCRIPTION

[0050] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0051] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0052] Reference Figure 1 The present application discloses a transcritical carbon dioxide energy storage system based on energy supplementing of gas storage, comprising:

[0053] A carbon dioxide capture system is used for capturing carbon dioxide in flue gas.

[0054] The transcritical carbon dioxide energy storage system comprises an energy storage mode and an energy release mode.

[0055] A waste heat utilization system is used for absorbing heat generated during carbon dioxide compression and work and providing cold energy and heat energy for terminals respectively.

[0056] The transcritical carbon dioxide energy storage system comprises an energy storage unit, an energy release unit, a depleted oil and gas reservoir high-pressure gas storage unit and a depleted oil and gas reservoir low-pressure gas storage unit connected in communication.

[0057] In the energy storage mode, the carbon dioxide capture system delivers carbon dioxide to the depleted oil and gas reservoir low-pressure gas storage unit, and at the same time, the energy storage unit compresses carbon dioxide in the depleted oil and gas reservoir low-pressure gas storage unit into a high-pressure state and delivers it to the depleted oil and gas reservoir high-pressure gas storage unit.

[0058] In the energy release mode, the carbon dioxide capture system compresses the carbon dioxide into high pressure state by the energy supplementing compressor 7 and delivers it into the depleted oil and gas reservoir high pressure storage unit, while the energy releasing unit releases the high pressure carbon dioxide in the depleted oil and gas reservoir high pressure storage unit and generates power by work, and delivers the carbon dioxide in low pressure state into the depleted oil and gas reservoir low pressure storage unit.

[0059] In use, the carbon dioxide in the flue gas is captured by the carbon dioxide capture system and delivered into the transcritical carbon dioxide energy storage system, in the energy storage stage, the carbon dioxide capture system delivers the low pressure carbon dioxide into the depleted oil and gas reservoir low pressure storage unit, while the energy storage unit compresses the carbon dioxide in the depleted oil and gas reservoir low pressure storage unit into high pressure state and delivers it into the depleted oil and gas reservoir high pressure storage unit, in the energy release stage, the carbon dioxide capture system compresses the low pressure carbon dioxide into high pressure state by the energy supplementing compressor 7 and delivers it into the depleted oil and gas reservoir high pressure storage unit, while the energy releasing unit releases the high pressure carbon dioxide in the depleted oil and gas reservoir high pressure storage unit and generates power by work, and delivers the carbon dioxide in low pressure state into the depleted oil and gas reservoir low pressure storage unit, the waste heat utilization system can absorb the heat generated during the compression and work of the carbon dioxide and provide cold energy and heat energy for the terminal respectively, compared with the traditional carbon dioxide energy storage system, the present application uses the depleted oil and gas reservoir as a storage tank to store high pressure and low pressure carbon dioxide, solves the problem of large capacity storage tank required by carbon dioxide energy storage, improves the work capacity of carbon dioxide by using the geothermal heat in the depleted oil and gas reservoir to heat the carbon dioxide, and improves the heat energy utilization rate of the carbon dioxide energy storage system. At the same time, the compression heat and cold energy recovered in the heat storage tank and the cold storage tank can also be supplied to the heat users and the cold users for use, realizing cold, heat and electricity triple generation, the system has high energy utilization efficiency, by using the carbon dioxide capture system to capture carbon dioxide, the captured carbon dioxide is injected into the low pressure and high pressure storage tank in the energy storage and energy release modes respectively, to maintain the pressure stability of the low pressure and high pressure storage tank, further improving the system performance.

[0060] In a further optimization scheme, the depleted oil and gas reservoir high pressure storage unit includes a high pressure injection well 13 and a high pressure recovery well 14, the first inlet of the high pressure injection well 13 is communicated with the outlet of the energy supplementing compressor 7, the second inlet of the high pressure injection well 13 is communicated with the outlet of the energy storage unit, the outlet of the high pressure injection well 13 is communicated with the inlet of the first depleted oil and gas reservoir storage space, the outlet of the first depleted oil and gas reservoir storage space is communicated with the inlet of the high pressure recovery well 14, and the outlet of the high pressure recovery well 14 is communicated with the inlet of the energy releasing unit through the high pressure throttling valve 15.

[0061] Further optimization scheme, the low-pressure gas storage unit of the depleted oil and gas reservoir includes a low-pressure injection well 21 and a low-pressure recovery well 22, a first inlet of the low-pressure injection well 21 is communicated with one of the outlets of the carbon dioxide capture system, a second inlet of the low-pressure injection well 21 is communicated with the outlet of the energy release unit, the outlet of the low-pressure injection well 21 is communicated with the inlet of the second depleted oil and gas reservoir storage space, and the outlet of the second depleted oil and gas reservoir storage space is communicated with the inlet of the energy storage unit.

[0062] Further optimization scheme, the energy release unit includes a high-pressure expander 16, a medium-pressure expander 17 and a low-pressure expander 18 arranged in sequence and communicated;

[0063] The inlet of the high-pressure expander 16 is communicated with the outlet of the high-pressure throttle valve 15;

[0064] The outlet of the low-pressure expander 18 is communicated with the inlet of the low-pressure injection well 21;

[0065] The waste heat utilization system is used for inter-stage heating of carbon dioxide during movement in the high-pressure expander 16, the medium-pressure expander 17 and the low-pressure expander 18, and low-temperature waste heat utilization.

[0066] Further optimization scheme, the energy storage unit includes a low-pressure compressor 8, a medium-pressure compressor 9 and a high-pressure compressor 10 arranged in sequence and communicated;

[0067] The inlet of the low-pressure compressor 8 is communicated with the outlet of the low-pressure recovery well 22, and the outlet of the high-pressure compressor 10 is communicated with the second inlet of the high-pressure injection well 13;

[0068] The waste heat utilization system is used for inter-stage heat absorption of carbon dioxide during movement in the low-pressure compressor 8, the medium-pressure compressor 9 and the high-pressure compressor 10.

[0069] Further optimization scheme, the outlet of the low-pressure recovery well 22 is communicated with the inlet of the low-pressure throttle valve 23, the outlet of the low-pressure throttle valve 23 is communicated with the inlet of the cooler 24, and the outlet of the cooler 24 is communicated with the inlet of the low-pressure compressor 8.

[0070] The transcritical carbon dioxide energy storage system includes an energy storage unit, an energy release unit, a depleted oil and gas reservoir high-pressure gas storage unit and a depleted oil and gas reservoir low-pressure gas storage unit.

[0071] The energy storage unit is used for compressing low-pressure carbon dioxide into a high-pressure state and delivering it to the depleted oil and gas reservoir high-pressure gas storage unit;

[0072] The energy release unit is used for high-temperature and high-pressure carbon dioxide to enter the expander to generate power, and the carbon dioxide after work is injected into the depleted oil and gas reservoir by the low-pressure injection well, and is used for the next cycle;

[0073] The depleted oil and gas reservoir high-pressure gas storage unit is used for high-pressure carbon dioxide storage and release;

[0074] The low-pressure gas storage unit of the depleted oil and gas reservoir is used for low-pressure carbon dioxide storage and release.

[0075] The further optimization scheme, the waste heat utilization system comprises a heat storage and high-temperature waste heat utilization unit, and a low-temperature waste heat utilization unit;

[0076] The low-temperature waste heat utilization unit is used for utilizing the low-temperature waste heat at the outlet of the low-pressure expander 18 to generate additional energy.

[0077] The heat storage and high-temperature waste heat utilization unit is used for recovering the compression heat of the carbon dioxide compression process, improving the carbon dioxide work process efficiency, and utilizing the high-temperature waste heat generated by the carbon dioxide capture system to improve the heat storage temperature, and simultaneously supplying part of the cold energy and the heat energy to the terminal for use.

[0078] The further optimization scheme, the low-temperature waste heat utilization unit comprises an evaporator 30, a turbine 27, a condenser 28 and a pump 29;

[0079] The heat source side inlet of the evaporator 30 is communicated with the outlet of the low-pressure expander 18, the heat source side outlet of the evaporator 30 is communicated with the inlet of the low-pressure injection well 21, the cold source side outlet of the evaporator 30 is communicated with the inlet of the turbine 27, the outlet of the turbine 27 is communicated with the heat source side inlet of the condenser 28, the heat source side outlet of the condenser 28 is communicated with the inlet of the pump 29, and the outlet of the pump 29 is communicated with the cold source side inlet of the evaporator 30;

[0080] The cold source side inlet of the condenser 28 is used for inputting cold energy.

[0081] The low-temperature waste heat utilization unit is used for utilizing the low-temperature waste heat at the outlet of the low-pressure expander 18 to generate additional energy, and further improving the energy utilization efficiency.

[0082] The low-temperature waste heat utilization system comprises a turbine 27, a condenser 28, a pump 29 and an evaporator 30.

[0083] The heat source side inlet of the evaporator 30 is connected with the outlet of the low-pressure expander 18, the low-temperature waste heat of the carbon dioxide at the outlet of the low-pressure expander 18 is used to convert the organic working medium from liquid state to gas state, the cold source side outlet of the evaporator 30 is connected with the inlet of the turbine 27, the gaseous organic working medium is used to generate power through the turbine 27, the outlet of the turbine 27 is connected with the heat source side of the condenser 28, the organic working medium is cooled to liquid state through the condenser 28, the heat source side outlet of the condenser 28 is connected with the pump 29, the outlet of the pump 29 is connected with the cold source side inlet of the evaporator 30, the liquid organic working medium is returned to the evaporator 30 through the pump 29, and the heat source side outlet of the evaporator 30 is connected with the inlet of the low-pressure injection well 21, and the utilization of the low-temperature waste heat is completed.

[0084] The low-temperature waste heat utilization system can utilize the low-temperature waste heat contained in the carbon dioxide at the outlet of the low-pressure expander 18 to generate additional electricity, improve the energy utilization rate of the system and output more electric energy.

[0085] The cold source side inlet of the condenser 28 in the low-temperature waste heat utilization system is connected to the cold energy, which can utilize the cold energy of liquefied natural gas or other cold energy.

[0086] In a further optimization scheme, the heat storage and high-temperature waste heat utilization unit includes a cold storage tank 25, a heat storage tank 26, a first inter-stage reheater 19, a second inter-stage reheater 20, a first inter-stage cooler 11 and a second inter-stage cooler 12.

[0087] The first inter-stage cooler 11 is connected between the low-pressure compressor 8 and the medium-pressure compressor 9, and the second inter-stage cooler 12 is connected between the medium-pressure compressor 9 and the high-pressure compressor 10.

[0088] The first inter-stage reheater 19 is connected between the high-pressure expander 16 and the medium-pressure expander 17, and the second inter-stage reheater 20 is connected between the medium-pressure expander 17 and the low-pressure expander 18.

[0089] The cold source side of the first inter-stage reheater 19, the second inter-stage reheater 20, the first inter-stage cooler 11 and the second inter-stage cooler 12 is connected to the cold storage tank 25.

[0090] The heat source side of the first inter-stage reheater 19, the second inter-stage reheater 20, the first inter-stage cooler 11 and the second inter-stage cooler 12 is connected to the heat storage tank 26.

[0091] In the energy storage mode, the cold storage tank 25 releases the cooling medium, absorbs the compression heat generated by the carbon dioxide compressed by the low-pressure compressor 8 and the medium-pressure compressor 9 through the first inter-stage cooler 11 and the second inter-stage cooler 12, and recovers and transports to the heat storage tank 26.

[0092] In the energy release mode, the heat storage tank 26 releases heat energy, and the first inter-stage reheater 19 and the second inter-stage reheater 20 increase the temperature of the carbon dioxide after the high-pressure expander 16 and the medium-pressure expander 17 work.

[0093] Part of the cold energy and part of the heat energy of the cold storage tank 25 and the heat storage tank 26 are used for terminal use.

[0094] The cold storage tank 25 and the heat storage tank 26 are used to recover the high-temperature waste heat generated by the carbon dioxide capture system.

[0095] The heat storage and high-temperature waste heat utilization unit is used to recover the compression heat in the compression process, and further increase the heat storage temperature by using the high-temperature waste heat generated by the capture system, while part of the cold energy and heat energy are supplied to the user for use.

[0096] The waste heat utilization system is used in cooperation with the transcritical carbon dioxide energy storage system, and is specifically provided as follows:

[0097] The transcritical carbon dioxide energy storage system specifically comprises a low-pressure compressor 8, a medium-pressure compressor 9, a high-pressure compressor 10, a first inter-stage cooler 11, a second inter-stage cooler 12, a high-pressure expander 16, a medium-pressure expander 17, a low-pressure expander 18, a first inter-stage reheater 19, a second inter-stage reheater 20, a cold storage tank 25, and a heat storage tank 26.

[0098] The transcritical carbon dioxide energy storage system comprises a low-pressure compressor 8, a medium-pressure compressor 9, a high-pressure compressor 10, a first inter-stage cooler 11, a second inter-stage cooler 12, a high-pressure expander 16, a medium-pressure expander 17, a low-pressure expander 18, a first inter-stage reheater 19, a second inter-stage reheater 20, a cold storage tank 25, and a heat storage tank 26.

[0099] The energy storage working mode: during the off-peak period of electricity consumption, the carbon dioxide in the low-pressure production well 22 is released, the temperature and pressure are maintained stable through the low-pressure throttle valve 23 and the cooler 24, and then the carbon dioxide enters the low-pressure compressor 8, the medium-pressure compressor 9 and the high-pressure compressor 10 to be compressed to a high-temperature and high-pressure state, during which the cold storage tank 25 releases the cooling medium, the compressed heat is recovered through the first inter-stage cooler 11 and the second inter-stage cooler 12 and is transported to the heat storage tank 26, and the carbon dioxide is injected into the first depleted oil and gas reservoir storage space from the high-pressure injection well 13, which is the energy storage working mode of the carbon dioxide energy storage system. At the same time of the energy storage working mode, the carbon dioxide captured in the carbon dioxide capture system is injected into the second depleted oil and gas reservoir storage space from the low-pressure injection well 21, so as to ensure the constant outlet pressure of the low-pressure production well 22 and improve the system performance.

[0100] The energy release working mode: during the peak period of electricity consumption, the high-temperature and high-pressure carbon dioxide in the high-pressure production well 14 is released, enters the high-pressure expander 16, the medium-pressure expander 17 and the low-pressure expander 18 to do work after the pressure is stabilized through the high-pressure throttle valve 15, during which the first inter-stage reheater 19 and the second inter-stage reheater 20 further heat the carbon dioxide by using the compressed heat stored in the heat storage tank 26 to improve the work capacity of the carbon dioxide and thus improve the system efficiency. The carbon dioxide after work is introduced into the evaporator 30, and the low-temperature waste heat of the carbon dioxide is utilized, and then the carbon dioxide is injected into the second depleted oil and gas reservoir storage space from the low-pressure injection well 21.

[0101] The transcritical carbon dioxide energy storage system uses the first depleted oil and gas reservoir storage space and the second depleted oil and gas reservoir storage space as gas storage to store carbon dioxide, can use geothermal energy to heat the carbon dioxide in the first depleted oil and gas reservoir storage space and the second depleted oil and gas reservoir storage space, can use more heat energy in the system, and can realize cold, heat and electricity combined production. Therefore, the heat energy in the heat storage tank 26 can be supplied to heat users for use, and the cold energy is recovered and transported to the cold storage tank 25. The cold energy in the cold storage tank 25 can be supplied to cold users for use, and the heat energy is recovered and transported to the heat storage tank 26.

[0102] The outlet of the low-pressure production well 22 is connected with the low-pressure throttle valve 23, the outlet of the low-pressure throttle valve 23 is connected with the inlet of the cooler 24, the outlet of the cooler 24 is connected with the inlet of the low-pressure compressor 8, the outlet of the low-pressure compressor 8 is connected with the heat source side inlet of the first inter-stage cooler 11, the outlet of the medium-pressure compressor 9 is connected with the heat source side inlet of the second inter-stage cooler 12, the heat source side outlet of the first inter-stage cooler 11 is connected with the inlet of the medium-pressure compressor 9, the heat source side outlet of the second inter-stage cooler 12 is connected with the inlet of the high-pressure compressor 10, the outlet of the high-pressure compressor 10 is connected with the high-pressure injection well 13, the cold source side inlets of the first inter-stage cooler 11 and the second inter-stage cooler 12 are both connected with the outlet of the cold storage tank 25, the cold source side outlets of the first inter-stage cooler 11 and the second inter-stage cooler 12 are both connected with the inlet of the heat storage tank 26, and the inlet of the high-pressure injection well 13 is further connected with the outlet of the energy supplementing compressor 7.

[0103] The outlet of the high-pressure production well 14 is connected with the inlet of the high-pressure throttle valve 15, the outlet of the high-pressure throttle valve 15 is connected with the inlet of the high-pressure expander 16, the outlet of the high-pressure expander 16 is connected with the cold source side inlet of the first inter-stage reheater 19, the cold source side outlet of the first inter-stage reheater 19 is connected with the inlet of the medium-pressure expander 17, the outlet of the medium-pressure expander 17 is connected with the cold source side inlet of the second inter-stage reheater 20, the cold source side outlet of the second inter-stage reheater 20 is connected with the inlet of the low-pressure expander 18, the outlet of the low-pressure expander 18 is connected with the heat source side inlet of the evaporator 30, the heat source side outlet of the evaporator 30 is connected with the inlet of the low-pressure injection well 21, the heat source side inlets of the first inter-stage reheater 19 and the second inter-stage reheater 20 are connected with the outlet of the heat storage tank 26, and the heat source side outlets of the first inter-stage reheater 19 and the second inter-stage reheater 20 are connected with the inlet of the cold storage tank 25.

[0104] Further optimization scheme, the carbon dioxide capture system comprises an absorption tower 1, a lean-rich liquid heat exchanger 2, a desorption tower 3, a reboiler 4, an alcohol amine solution / conductive oil heat exchanger 5 and an alcohol amine solution storage tank 6;

[0105] The top inlet of the absorption tower 1 is communicated with the outlet of the alcohol amine solution storage tank 6, the bottom outlet of the absorption tower 1 is communicated with the cold source side inlet of the lean-rich liquid heat exchanger 2, the cold source side outlet of the lean-rich liquid heat exchanger 2 is communicated with the top inlet of the desorption tower 3, the top outlet of the desorption tower 3 is communicated with the inlet of the energy supplementing compressor 7 and the inlet of the low-pressure injection well 21 respectively, the bottom outlet of the desorption tower 3 is communicated with the inlet of the reboiler 4, the top outlet of the reboiler 4 is communicated with the bottom inlet of the desorption tower 3, the bottom outlet of the reboiler 4 is communicated with the heat source side inlet of the lean-rich liquid heat exchanger 2, the heat source side outlet of the lean-rich liquid heat exchanger 2 is communicated with the heat source side inlet of the alcohol amine solution / conductive oil heat exchanger 5, the heat source side outlet of the alcohol amine solution / conductive oil heat exchanger 5 is communicated with the inlet of the alcohol amine solution storage tank 6, the cold source side inlet of the alcohol amine solution / conductive oil heat exchanger 5 is communicated with the outlet of the cold storage tank 25, and the cold source side outlet of the alcohol amine solution / conductive oil heat exchanger 5 is communicated with the inlet of the heat storage tank 26.

[0106] The carbon dioxide capture system is used for capturing carbon dioxide in flue gas, and injecting the carbon dioxide into corresponding depleted oil and gas reservoirs by high-pressure injection well 13 and low-pressure injection well 21 respectively, supplementing formation energy, maintaining constant pressure of high-pressure production well and low-pressure production well outlet in energy storage stage, improving system stability, and improving heat storage temperature by using high-temperature waste heat generated in the system.

[0107] The carbon dioxide capture system comprises an absorption tower 1, a lean- rich liquid heat exchanger 2, a desorption tower 3, a reboiler 4, an alcohol amine solution / heat conducting oil heat exchanger 5 and an alcohol amine solution storage tank 6, the top inlet of the absorption tower 1 is connected with the outlet of the alcohol amine solution storage tank 6; the bottom outlet of the absorption tower 1 is connected with the cold source side inlet of the lean- rich liquid heat exchanger 2; the cold source side outlet of the lean- rich liquid heat exchanger 2 is connected with the top inlet of the desorption tower 3; the top outlet of the desorption tower is connected with the low-pressure injection well 21 and the energy supplementing compressor 7 respectively; the bottom outlet of the desorption tower 3 is connected with the inlet of the reboiler 4, the top outlet of the reboiler 4 is connected with the bottom inlet of the desorption tower 3, and the bottom outlet of the reboiler 4 is connected with the heat source side inlet of the lean- rich liquid heat exchanger 2; the heat source side outlet of the lean- rich liquid heat exchanger 2 is connected with the heat source side inlet of the alcohol amine solution / heat conducting oil heat exchanger 5; the heat source side outlet of the alcohol amine solution / heat conducting oil heat exchanger 5 is connected with the alcohol amine solution storage tank 6; the cold source side inlet of the alcohol amine solution / heat conducting oil heat exchanger 5 is connected with the outlet of the cold storage tank 25, and the cold source side outlet of the alcohol amine solution / heat conducting oil heat exchanger 5 is connected with the inlet of the heat storage tank 26.

[0108] The flue gas of industrial emission carbon dioxide is transported to the bottom of the absorption tower 1 after denitration and desulfurization, and the flue gas at the bottom is countercurrently contacted with alcohol amine lean liquid (alcohol amine solution not absorbing carbon dioxide is called lean liquid) flowing down from the top to realize absorption of carbon dioxide. The flue gas from which carbon dioxide is removed is discharged from the top of the absorption tower 1; the alcohol amine rich liquid is sent into the desorption tower 3 after heat exchange treatment of the lean- rich liquid heat exchanger 2 (the operating temperature of the absorption tower 1 is lower than that of the desorption tower 3, so it needs to be heated through the lean- rich liquid heat exchanger 2) to perform desorption and regeneration treatment. In the desorption process, the rich liquid is decomposed by steam heating in the desorption tower 3, and alcohol amine and carbon dioxide are regenerated. At this time, part of the alcohol amine solution not absorbing carbon dioxide is discharged through the bottom, enters the reboiler 4 again to be heated to completely desorb carbon dioxide, and the desorbed carbon dioxide enters the desorption tower 3 and is discharged from the top, and is injected into the depleted oil and gas reservoir by the low-pressure injection well 21 and the high-pressure injection well 13 in energy storage and energy release modes respectively; the desorbed alcohol amine solution is transported into the alcohol amine solution storage tank 6 after being cooled to be equivalent to the temperature of the flue gas by the lean- rich liquid heat exchanger 2 and the alcohol amine solution / heat conducting oil heat exchanger 5 (which can also be an alcohol amine solution / cooling water heat exchanger or other heat storage medium) again, and is recycled for use again in the next capture system operation.

[0109] The carbon dioxide captured by the carbon dioxide capture system, i.e. the carbon dioxide discharged from the top of the desorption tower 3, is utilized in the transcritical carbon dioxide energy storage system.

[0110] When the transcritical carbon dioxide energy storage system is in the energy storage mode, the carbon dioxide at the top is injected into the depleted oil and gas reservoir by the low-pressure injection well 21 to maintain the stability of the energy storage stage pressure; when the transcritical carbon dioxide energy storage system is in the energy release mode, the carbon dioxide at the top is compressed by the energy supplementing compressor 7 and then injected into the depleted oil and gas reservoir by the high-pressure injection well 13 to maintain the stability of the energy release stage pressure.

[0111] The temperature of the carbon dioxide captured by the carbon dioxide capture system is relatively high after heat exchange in the lean-rich liquid heat exchanger 2, and the alcohol amine solution / conductive oil heat exchanger 5 is used for heat exchange to increase the temperature of the heat storage tank 26 by using high-temperature waste heat.

[0112] In the description of the present application, it should be understood that the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the present application, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0113] The above-described embodiments are only used to describe the preferred modes of the present application, and do not limit the scope of the present application, and various modifications and improvements to the technical solutions of the present application made by those skilled in the art without departing from the design spirit of the present application shall fall within the protection scope of the present application.

Claims

1. A transcritical carbon dioxide energy storage system based on energy compensation of gas storage, characterized in that, The application relates to a carbon dioxide capture system, a transcritical carbon dioxide energy storage system, and a waste heat utilization system. The transcritical carbon dioxide energy storage system comprises an energy storage unit, an energy release unit, a depleted oil and gas reservoir high-pressure gas storage unit, and a depleted oil and gas reservoir low-pressure gas storage unit. In the energy storage mode, the carbon dioxide capture system delivers carbon dioxide to the depleted oil and gas reservoir low-pressure gas storage unit, and the energy storage unit compresses the carbon dioxide in the depleted oil and gas reservoir low-pressure gas storage unit into a high-pressure state and delivers the carbon dioxide to the depleted oil and gas reservoir high-pressure gas storage unit. In the energy release mode, the carbon dioxide capture system compresses carbon dioxide into a high-pressure state through a supplemental compressor (7) and delivers the carbon dioxide to the depleted oil and gas reservoir high-pressure gas storage unit, and the energy release unit releases the high-pressure carbon dioxide in the depleted oil and gas reservoir high-pressure gas storage unit and generates power through work, and delivers the carbon dioxide in a low-pressure state to the depleted oil and gas reservoir low-pressure gas storage unit. The depleted oil and gas reservoir high-pressure gas storage unit comprises a high-pressure injection well (13) and a high-pressure recovery well (14), a first inlet of the high-pressure injection well (13) is communicated with an outlet of the supplemental compressor (7), a second inlet of the high-pressure injection well (13) is communicated with an outlet of the energy storage unit, an outlet of the high-pressure injection well (13) is communicated with an inlet of a first depleted oil and gas reservoir storage space, an outlet of the first depleted oil and gas reservoir storage space is communicated with an inlet of the high-pressure recovery well (14), and an outlet of the high-pressure recovery well (14) is communicated with an inlet of the energy release unit through a high-pressure throttling valve (15). The depleted oil and gas reservoir low-pressure gas storage unit comprises a low-pressure injection well (21) and a low-pressure recovery well (22), a first inlet of the low-pressure injection well (21) is communicated with one of the outlets of the carbon dioxide capture system, a second inlet of the low-pressure injection well (21) is communicated with an outlet of the energy release unit, and an outlet of the low-pressure injection well (21) is communicated with an inlet of a second depleted oil and gas reservoir storage space. The energy release unit comprises a high-pressure expander (16), a medium-pressure expander (17), and a low-pressure expander (18) which are sequentially communicated. An inlet of the high-pressure expander (16) is communicated with an outlet of the high-pressure throttling valve (15). An outlet of the low-pressure expander (18) is communicated with an inlet of the low-pressure injection well (21). The waste heat utilization system is used for inter-stage heating of carbon dioxide during movement of the high-pressure expander (16), the medium-pressure expander (17), and the low-pressure expander (18) and low-temperature waste heat utilization. The energy storage unit comprises a low-pressure compressor (8), a medium-pressure compressor (9), and a high-pressure compressor (10) which are sequentially communicated. ​ ​ 2. The transcritical carbon dioxide based energy storage system according to claim 1, wherein: ​ The inlet of the low-pressure compressor (8) is communicated with the outlet of the low-pressure recovery well (22), and the outlet of the high-pressure compressor (10) is communicated with the second inlet of the high-pressure injection well (13); The waste heat utilization system is used for inter-stage heat absorption of carbon dioxide during movement of the low-pressure compressor (8), the medium-pressure compressor (9) and the high-pressure compressor (10).

3. The transcritical carbon dioxide based energy storage system according to claim 2, wherein: The outlet of the low-pressure recovery well (22) is communicated with the inlet of a low-pressure throttle valve (23), the outlet of the low-pressure throttle valve (23) is communicated with the inlet of a cooler (24), and the outlet of the cooler (24) is communicated with the inlet of the low-pressure compressor (8).

4. The transcritical carbon dioxide based energy storage system according to claim 2, wherein: The waste heat utilization system comprises a heat storage and high-temperature waste heat utilization unit and a low-temperature waste heat utilization unit; The low-temperature waste heat utilization unit is used for utilizing low-temperature waste heat at the outlet of the low-pressure expander (18) to generate additional energy; The heat storage and high-temperature waste heat utilization unit is used for recovering compression heat of carbon dioxide compression, improving carbon dioxide work process efficiency, and improving heat storage temperature by utilizing high-temperature waste heat generated by the carbon dioxide capture system, while supplying part of cold energy and heat energy to a terminal for use.

5. The transcritical carbon dioxide based energy storage system according to claim 4, wherein: The low-temperature waste heat utilization unit comprises an evaporator (30), a turbine (27), a condenser (28) and a pump (29); The heat source side inlet of the evaporator (30) is communicated with the outlet of the low-pressure expander (18), the heat source side outlet of the evaporator (30) is communicated with the inlet of the low-pressure injection well (21), the cold source side outlet of the evaporator (30) is communicated with the inlet of the turbine (27), the outlet of the turbine (27) is communicated with the heat source side inlet of the condenser (28), the heat source side outlet of the condenser (28) is communicated with the inlet of the pump (29), and the outlet of the pump (29) is communicated with the cold source side inlet of the evaporator (30); The cold source side inlet of the condenser (28) is used for inputting cold energy.

6. The transcritical carbon dioxide based energy storage system according to claim 4, wherein: The heat storage and high-temperature waste heat utilization unit comprises a cold storage tank (25), a heat storage tank (26), a first inter-stage reheater (19), a second inter-stage reheater (20), a first inter-stage cooler (11) and a second inter-stage cooler (12); The first inter-stage cooler (11) is arranged between the low-pressure compressor (8) and the medium-pressure compressor (9), and the second inter-stage cooler (12) is arranged between the medium-pressure compressor (9) and the high-pressure compressor (10); The first inter-stage reheater (19) is arranged between the high-pressure expander (16) and the medium-pressure expander (17), and the second inter-stage reheater (20) is arranged between the medium-pressure expander (17) and the low-pressure expander (18); The cold source side of the first inter-stage reheater (19), the second inter-stage reheater (20), the first inter-stage cooler (11) and the second inter-stage cooler (12) is communicated with the cold storage tank (25). The heat storage tank (26) is in communication with the heat source side of the first inter-stage reheater (19), the second inter-stage reheater (20), the first inter-stage cooler (11) and the second inter-stage cooler (12); In the energy storage mode, the cold storage tank (25) releases cooling medium, absorbs the compression heat of the carbon dioxide compressed by the low-pressure compressor (8) and the medium-pressure compressor (9) through the first inter-stage cooler (11) and the second inter-stage cooler (12), recovers and transports to the heat storage tank (26); In the energy release mode, the heat storage tank (26) releases heat energy, and the first inter-stage reheater (19) and the second inter-stage reheater (20) increase the temperature of the carbon dioxide after the work of the high-pressure expander (16) and the medium-pressure expander (17); Part of the cold energy and part of the heat energy of the cold storage tank (25) and the heat storage tank (26) are used for terminal use; The cold storage tank (25) and the heat storage tank (26) are used to recover the high-temperature waste heat generated by the carbon dioxide capture system.

7. The transcritical carbon dioxide based energy storage system according to claim 6, wherein: The carbon dioxide capture system comprises an absorption tower (1), a lean-rich liquid heat exchanger (2), a desorption tower (3), a reboiler (4), an alcohol amine solution / conductive oil heat exchanger (5) and an alcohol amine solution storage tank (6); The top inlet of the absorption tower (1) is in communication with the outlet of the alcohol amine solution storage tank (6), the bottom outlet of the absorption tower (1) is in communication with the cold source side inlet of the lean-rich liquid heat exchanger (2), the cold source side outlet of the lean-rich liquid heat exchanger (2) is in communication with the top inlet of the desorption tower (3), the top outlet of the desorption tower (3) is in communication with the inlet of the energy supplementing compressor (7) and the inlet of the low-pressure injection well (21) respectively, the bottom outlet of the desorption tower (3) is communicated with the reboiler (4) inlet, the top outlet of the reboiler (4) is in communication with the bottom inlet of the desorption tower (3), the bottom outlet of the reboiler (4) is in communication with the heat source side inlet of the lean-rich liquid heat exchanger (2), the heat source side outlet of the lean-rich liquid heat exchanger (2) is in communication with the heat source side inlet of the alcohol amine solution / conductive oil heat exchanger (5), the heat source side outlet of the alcohol amine solution / conductive oil heat exchanger (5) is in communication with the inlet of the alcohol amine solution storage tank (6), the cold source side inlet of the alcohol amine solution / conductive oil heat exchanger (5) is in communication with the outlet of the cold storage tank (25), and the cold source side outlet of the alcohol amine solution / conductive oil heat exchanger (5) is in communication with the inlet of the heat storage tank (26).

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