Compressed gas energy storage system based on pressure swing adsorption carbon capture and operation method thereof

Abstract

The invention relates to a compression energy storage and carbon capture technology, in particular to a compressed gas energy storage system based on pressure swing adsorption carbon capture and an operation method of the compressed gas energy storage system. The energy storage system comprises a gas pretreatment device, a gas compression device, a gas storage, a gas expansion device and a pressure swing adsorption carbon capture device. An exhaust port of the gas pretreatment device is connected with a gas inlet of the gas compression device; an exhaust port of the gas compression device is connected with a gas inlet of the gas storage; an exhaust port of the gas storage is connected with a gas inlet of the gas expansion device; and the pressure swing adsorption carbon capture device is arranged between the gas inlet of the gas compression device and the exhaust port of the gas expansion device. According to the energy storage system, in the compressed air energy storage process, potential energy of compressed air can be fully utilized, and more efficient carbon capture is achieved.

Description

Technical Field

[0001] The present invention relates to compressed energy storage and carbon capture technologies, and specifically to a compressed gas energy storage system based on pressure swing adsorption carbon capture and its operation method. Background Art

[0002] As the main power source for power supply, thermal power generation using fossil energy combustion as the energy supply method has led to high carbon emissions. The flue gas generated by thermal power combustion usually contains about 12% carbon dioxide, which has high capture and storage value.

[0003] Currently, carbon dioxide capture usually adopts the chemical absorption method, that is, the gas containing carbon dioxide is introduced into an amine solution for absorption. Since the absorbent is a dilute solution with certain volatility and regeneration often requires heating, the equipment used in this method is relatively large and energy consumption is high. At the same time, there is also the problem of aerosol pollution, which is likely to have an adverse impact on the environment.

[0004] As a new carbon capture technology, pressure swing adsorption uses the different adsorption characteristics of gas components on the adsorbent and the characteristic that the adsorption amount changes with pressure to capture specific gases. This technology has a simple process, low energy consumption, no pollution, and has good development prospects.

[0005] In addition, to achieve power grid peak shaving, an energy storage system is usually configured for thermal power units. Currently, the relatively mature large-scale energy storage technologies mainly include pumped hydro storage, battery energy storage, and compressed air energy storage. Among them, pumped hydro storage is strictly restricted by geographical and ecological conditions, and there are certain limitations in application and promotion. Battery energy storage is restricted by cost and environmental protection issues, and large-scale applications are limited. The main principle of compressed gas energy storage technology is: using a compressor to convert electrical energy into the pressure energy of gas for storage, and using a turbine to convert the pressure energy of gas into electrical energy when needed. In comparison, compressed air energy storage technology has the advantages of flexible site selection, simple structure, large energy storage capacity, reliable technology, long operation life, etc., and has a good market prospect. Summary of the Invention

[0006] In view of the above problems, the present invention provides a compressed gas energy storage system based on pressure swing adsorption carbon capture and its operation method, which can make full use of the potential energy of compressed gas during the process of compressed air energy storage to achieve more efficient carbon capture.

[0007] The first aspect of the present invention provides a compressed gas energy storage system based on pressure swing adsorption carbon capture, including:

[0008] A gas pretreatment device;

[0009] A gas compression device, the exhaust port of the gas pretreatment device is connected to the intake port of the gas compression device;

[0010] Gas storage reservoir, the exhaust port of the gas compression device is connected to the intake port of the gas storage reservoir;

[0011] Gas expansion device, the exhaust port of the gas storage reservoir is connected to the intake port of the gas expansion device;

[0012] Pressure swing adsorption carbon capture device, the pressure swing adsorption carbon capture device is arranged between the intake port of the gas compression device and the exhaust port of the gas expansion device.

[0013] Optionally, the pressure swing adsorption carbon capture device includes:

[0014] At least two pressure swing adsorption towers, one or more layers of adsorption beds are arranged in the pressure swing adsorption towers, and the adsorption beds are filled with adsorbents for adsorbing carbon dioxide in the gas. The adsorbents include one or a combination of activated carbon, silica gel, molecular sieve, metal organic framework materials, etc.;

[0015] Carbon dioxide storage tank, connected to the pressure swing adsorption tower, and the carbon dioxide desorbed from the adsorbent is introduced into the carbon dioxide storage tank.

[0016] Optionally, the pressure swing adsorption carbon capture device further includes a pressure stabilizing tank, which is arranged between the pressure swing adsorption tower and the gas storage reservoir.

[0017] Optionally, multiple pressure swing adsorption towers of the pressure swing adsorption carbon capture device are arranged in parallel and perform a pressure swing adsorption cycle periodically to continuously produce carbon dioxide into the carbon dioxide storage tank.

[0018] Optionally, the gas pretreatment device includes:

[0019] Condenser, the raw gas enters the gas pretreatment device through the intake port of the condenser;

[0020] Desulfurization tower, the exhaust port of the condenser is connected to the intake port of the desulfurization tower;

[0021] Denitrification tower, the exhaust port of the desulfurization tower is connected to the intake port of the denitrification tower;

[0022] Dust collector, the exhaust port of the denitrification tower is connected to the intake port of the dust collector, and the exhaust port of the dust collector is connected to the intake port of the gas compression device.

[0023] Optionally, the gas compression device includes multiple compressors connected in series. The intake port of one compressor is connected to the exhaust port of the gas pretreatment device, and the exhaust port of another compressor is connected to the intake port of the gas storage reservoir; and / or,

[0024] The gas expansion device includes multiple turbines connected in series. The compressed gas entering the gas expansion device drives the turbines to generate electricity. The intake port of one turbine is connected to the exhaust port of the gas storage tank, and the exhaust port of another turbine discharges the remaining gas that has completed the expansion work to the outside.

[0025] Optionally, the system further includes a heat exchange device, which is arranged between the gas compression device and the gas expansion device;

[0026] The heat exchange device includes:

[0027] A heat exchanger, which is arranged near the exhaust port of the compressor and the intake port of the turbine, and inside the pressure swing adsorption tower of the pressure swing adsorption carbon capture device;

[0028] A heat storage tank, with a heat storage medium arranged inside;

[0029] Heat exchange tubes, the heat exchanger and the heat storage tank are connected by the heat exchange tubes, and a heat exchange medium is arranged inside the heat exchange tubes;

[0030] A heat exchange pump, which is arranged inside the heat exchange tubes and drives the heat exchange medium in the heat exchange tubes to circulate between the heat exchanger and the heat storage tank.

[0031] The second aspect of the present invention provides an operation method of the above compressed gas energy storage system based on pressure swing adsorption carbon capture, including the following steps:

[0032] Gas pretreatment step: The gas to be treated enters the gas pretreatment device for pretreatment;

[0033] Gas boosting step: Boost the pressure of the pretreated gas entering the gas compression from the gas pretreatment device;

[0034] Gas storage step: Store the compressed gas entering the gas storage tank from the gas compression device;

[0035] Gas expansion step: Expand and do work on the compressed gas entering the gas expansion device from the gas storage tank;

[0036] Pressure swing adsorption carbon capture step: Perform pressure swing adsorption or storage of carbon dioxide in the gas flowing between the intake port of the gas compression device and the exhaust port of the gas expansion device.

[0037] Optionally, the gas boosting step and the gas storage step are driven by the excess electricity generated by the generator set, and the gas expansion step uses the gas expansion to drive the turbine to generate electricity; in the pressure swing adsorption carbon capture step, the pressure swing adsorption carbon capture device uses the heat energy or air energy generated by the compressed gas to increase the adsorption amount of the adsorbent for carbon dioxide.

[0038] Optionally, the operation method further includes:

[0039] Purge step: The remaining gas in multiple pressure swing adsorption towers after the pressure swing adsorption carbon capture step enters another pressure swing adsorption tower other than itself to purge and regenerate the adsorbent in the other pressure swing adsorption tower.

[0040] Heat exchange step: For:

[0041] Cool down the compressed gas generated by the gas boosting step through heat exchange;

[0042] Heat up the compressed gas before the gas expansion step through heat exchange; and

[0043] Heat up the pressure swing adsorption tower after the pressure swing adsorption carbon capture step through heat exchange.

[0044] The compressed gas energy storage system based on pressure swing adsorption carbon capture provided by the present invention can be applied to peak shaving energy storage in the power system, can convert excess electric energy into the pressure energy and heat energy of flue gas and store them, and at the same time capture carbon dioxide in the flue gas to reduce the carbon emission of thermal power units. When the stored electric energy needs to be used, the potential energy of the flue gas is converted into electric energy and transmitted to the power system. In addition, the pressure energy and heat energy in the compressed flue gas can enable the carbon dioxide contained in the flue gas to be captured more efficiently in the energy storage system, so as to maximize the utilization of flue gas resources. Description of the Drawings

[0045] Figure 1 It is a schematic diagram of the operation module of an energy storage system provided in the first embodiment of the present invention.

[0046] Figure 2 It is another schematic diagram of the operation module of an energy storage system provided in the first embodiment of the present invention.

[0047] Figure 3 It is another schematic diagram of the structure of an energy storage system provided in the first embodiment of the present invention.

[0048] Figure 4 It is a schematic diagram of the operation module of an energy storage system provided in the second embodiment of the present invention.

[0049] Figure 5 It is another schematic diagram of the operation module of an energy storage system provided in the second embodiment of the present invention.

[0050] Figure 6 It is another schematic diagram of the structure of an energy storage system provided in the second embodiment of the present invention.

[0051] Figure 7 It is a schematic diagram of the operation module of an energy storage system provided in the third embodiment of the present invention.

[0052] Figure 8 It is a schematic diagram of an operation module of an energy storage system provided in the fourth embodiment of the present invention.

[0053] Figure 9 It is a schematic structural diagram of a pressure swing adsorption carbon capture device provided in the first embodiment of the present invention.

[0054] Reference numerals: 100 - energy storage system, 1 - gas compression device, 11 - compressor, 2 - gas expansion device, 21 - turbine, 3 - gas storage reservoir, 4 - pressure swing adsorption carbon capture device, 41 - pressure swing adsorption tower, 41A - first pressure swing adsorption tower, 41B - second pressure swing adsorption tower, 411 - intake valve, 412 - product gas valve, 413 - waste gas valve, 42 - carbon dioxide storage tank, 43 - pressure stabilizing tank, 5 - gas pretreatment device, 51 - condenser, 52 - desulfurization tower, 53 - denitration tower, 54 - dust collector. 6 - heat exchange device, 61 - first heat exchanger, 62 - second heat exchanger, 63 - heat storage tank. Detailed implementation manners

[0055] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0056] <First Embodiment>

[0057] Figure 1 It is a schematic diagram of an operation module of an energy storage system 100 provided in this embodiment. Refer to Figure 1 , the energy storage system 100 provided in this embodiment includes a gas pretreatment device 5, a gas compression device 1, a gas storage reservoir 3, a gas expansion device 2, and a pressure swing adsorption carbon capture device 4. Among them, the exhaust port of the gas pretreatment device 5 is connected to the intake port of the gas compression device 1; the exhaust port of the gas compression device 1 is connected to the intake port of the gas storage reservoir 3; the exhaust port of the gas storage reservoir 3 is connected to the intake port of the gas expansion device 2; the pressure swing adsorption carbon capture device 4 is disposed between the intake port of the gas compression device 1 and the exhaust port of the gas expansion device 2.

[0058] During the operation of thermal power units, a large amount of flue gas containing a certain proportion of carbon dioxide is generated. To avoid environmental problems such as greenhouse effect and excessive carbon emissions caused by direct flue gas emissions, the energy storage system 100 provided in this embodiment can not only utilize the excess electric energy generated by the power system during a certain period, compress the flue gas generated by the thermal power unit, and store the compressed flue gas in the gas storage reservoir 3. During the flue gas compression process, the generated flue gas pressure energy and thermal energy are collected and stored by the energy storage system 100. Through the gas expansion device 2 of the energy storage system 100, a part of the energy in the flue gas potential energy generated during the above flue gas compression process can be converted into electric energy again during a certain period and transmitted to the power system to complete the peak regulation of electric energy in the power system. At the same time, the pressure swing adsorption carbon capture device 4 in the energy storage system 100 can also utilize a part of the flue gas potential energy generated during the flue gas compression process to capture and separate carbon dioxide in the flue gas, and this part of carbon dioxide can be transferred to other devices for effective utilization or harmless treatment.

[0059] Reference Figure 1 , the operation process of the energy storage system 100 in this embodiment is as follows: Under the charging condition, the external flue gas enters the gas pretreatment device 5, and the gas pretreatment device 5 removes impurities from the flue gas. The pretreated flue gas enters the gas compression device 1, and the gas compression device 1 compresses it to obtain compressed flue gas. The compressed flue gas enters the pressure swing adsorption carbon capture device 4 for carbon dioxide capture, and the flue gas after adsorption is transported to the gas storage reservoir 3 for storage. Under the deflation condition of the energy storage system 100, the compressed flue gas stored in the gas storage reservoir 3 flows into the gas expansion device 2, and the gas expansion device 2 expands the flue gas to generate electric energy and transports it to external equipment.

[0060] Figure 3 is a schematic structural diagram of the energy storage system 100 provided in this embodiment. Since the flue gas directly discharged from the thermal power unit contains various other impurities that are not conducive to the operation of the energy storage system 100, the flue gas first enters the gas pretreatment device 5 through the air inlet of the gas pretreatment device 5 for flue gas pretreatment and impurity removal. In this embodiment, the gas pretreatment device 5 includes a condenser 51, a desulfurization tower 52, a denitration tower 53, and a dust collector 54. Reference Figure 3 , the original gas enters the gas pretreatment device 5 through the air inlet of the condenser 51; among them, the exhaust port of the condenser 51 is connected to the air inlet of the desulfurization tower 52; the exhaust port of the desulfurization tower 52 is connected to the air inlet of the denitration tower 53; the exhaust port of the denitration tower 53 is connected to the air inlet of the dust collector 54, and the exhaust port of the dust collector 54 is connected to the air inlet of the gas compression device 1. The original flue gas sequentially passes through the condenser 51, the desulfurization tower 52, the denitration tower 53, and the dust collector 54 to complete the removal of water vapor, sulfides, nitrides, and dust. Reference Figure 2, a water outlet is also provided in the condenser 51, and the moisture contained in the raw flue gas is condensed in the condenser 51 and discharged from the water outlet.

[0061] In this embodiment, the gas compression device 1 is used to compress the flue gas to increase the pressure of the flue gas, and the pressure and temperature of the flue gas increase in the gas compression device 1. Refer to Figure 3 , the gas compression device 1 includes multiple compressors 11 connected in series. The intake port of one compressor 11 is connected to the exhaust port of the gas pretreatment device 5, and the exhaust port of another compressor 11 is connected to the intake port of the gas storage tank 3. Multiple compressors 11 connected in series perform multistage compression, which can save compression power consumption and improve the cylinder volume utilization rate of the compressor 11. Part of the surplus electric energy generated by the power system drives the compressor 11 to operate and compresses the raw flue gas entering the compressor 11. At this time, the surplus electric energy is converted into the compression potential energy of the flue gas, including the pressure energy and heat energy of the compressed flue gas. The flue gas compressed in the gas compression device 1 is then transferred to the gas storage tank 3 for storage of the compressed flue gas under the drive of part of the surplus electric energy.

[0062] In this embodiment, when the power system has a peak shaving demand for the electric energy stored in the energy storage system 100, the connection valve between the gas storage tank 3 and the gas expansion device 2 is opened, and the compressed flue gas in the gas storage tank 3 flows to the gas expansion device 2 to expand and do work to meet the power generation needs, and the electric energy generated during the expansion process is transmitted to external equipment. Refer to Figure 3 , the gas expansion device 2 includes multiple turbines 21 connected in series. The compressed gas entering the gas expansion device 2 drives the turbines 21 to generate electricity. The intake port of the first turbine 21 connected to the gas storage tank 3 is connected to the exhaust port of the gas storage tank 3, and the exhaust port of the last turbine 21 connected in series in sequence discharges the remaining flue gas that has completed the expansion work to other equipment outside the energy storage system 100 or directly discharges it to the outside. Multiple turbines 21 connected in series perform multistage expansion, which can effectively improve the expansion work and thus improve the electric energy conversion efficiency of the entire energy storage system 100. In other embodiments, in the gas compression device 1 and the gas expansion device 2, gas compression / expansion can be achieved by a combination of one or more devices or apparatuses, and no specific limitation is made here.

[0063] In this embodiment, the pressure swing adsorption carbon capture device 4 is arranged between the exhaust port of the gas compression device 1 and the intake port of the gas storage tank 3. After the compressed flue gas discharged from the gas compression device 1 enters the pressure swing adsorption carbon capture device 4, the carbon dioxide in the compressed flue gas is subjected to pressure swing adsorption and stored in the pressure swing adsorption carbon capture device 4. The remaining compressed flue gas that has completed carbon dioxide capture will be introduced into the gas storage tank 3 for storage. Refer to Figure 3, the pressure swing adsorption carbon capture device 4 includes two pressure swing adsorption towers 41 and a carbon dioxide storage tank 42. Among them, one or more layers of adsorption beds are provided in the pressure swing adsorption tower 41, and the adsorption beds are filled with adsorbents for adsorbing carbon dioxide in the gas. The adsorbents include one or a combination of activated carbon, silica gel, molecular sieve, and metal-organic framework materials. In other embodiments, other types of adsorbents may also be used according to the specific use environment, and no specific limitations are made here. The carbon dioxide storage tank 42 is connected to the pressure swing adsorption tower 41, and the carbon dioxide desorbed from the adsorbent is introduced into the carbon dioxide storage tank 42. In other embodiments, the number of pressure swing adsorption towers 41 may also be more than two, and the specific number is planned according to the carbon dioxide capture target of the energy storage system 100, and no specific limitations are made here.

[0064] In the above energy storage system 100, pressure swing adsorption is performed on the flue gas before it is compressed and enters the gas storage reservoir 3. Since the partial pressure of carbon dioxide in the compressed flue gas is relatively high, according to the adsorption kinetics analysis, the adsorption capacity of the adsorbent is significantly increased compared to the atmospheric pressure condition. The pressure swing adsorption carbon capture device 4 makes full use of the pressure energy of the compressed gas for carbon dioxide capture, reducing the carbon emissions of the flue gas.

[0065] Reference Figure 3 , the two pressure swing adsorption towers 41 of the pressure swing adsorption carbon capture device 4 are respectively the first pressure swing adsorption tower 41A and the second pressure swing adsorption tower 41B, which are arranged in parallel and periodically perform a pressure swing adsorption cycle to continuously produce carbon dioxide into the carbon dioxide storage tank 42, and the remaining compressed flue gas enters the gas storage reservoir 3 through the exhaust port of the adsorption tower.

[0066] Figure 9 is a schematic structural diagram of the pressure swing adsorption carbon capture device 4 provided in this embodiment. As Figure 9 shown, the pressure swing adsorption carbon capture device 4 further includes an intake valve 411, a product gas valve 412, and an exhaust gas valve 413; the pressure swing adsorption tower 41 completes each link of the pressure swing adsorption carbon capture by adjusting the opening and closing of each valve.

[0067] In this embodiment, the carbon dioxide capture process of the pressure swing adsorption carbon capture device 4 is as follows: Open the intake valve 411 of the first pressure swing adsorption tower 41A and close the waste gas valve 413. At the same time, close the intake valve 411 of the second pressure swing adsorption tower 41B, and make the compressed flue gas flow into the first pressure swing adsorption tower 41A under the drive of pressure. As the flue gas continuously enters the first pressure swing adsorption tower 41A and the flue gas pressure inside reaches the adsorption pressure of the adsorbent for carbon dioxide, close the intake valve 411 to stop the intake. At this time, the adsorbent in the first pressure swing adsorption tower 41A starts to automatically adsorb the carbon dioxide doped in the compressed flue gas in the tower under the high-pressure state, and the adsorbent in the first pressure swing adsorption tower 41A adsorbs the carbon dioxide in the flue gas under the high-pressure state. In the pressure swing adsorption tower 41 in this embodiment, a gas quality detection device (not shown in the figure) is provided. When the gas quality detection device shows that the gas quality in the first pressure swing adsorption tower 41A no longer changes, it means that the carbon dioxide doped in the compressed flue gas in the first pressure swing adsorption tower 41A has been completely adsorbed by the adsorbent or the adsorption amount of the adsorbent for carbon dioxide has reached saturation. At this time, the carbon dioxide adsorption process in the first pressure swing adsorption tower 41A ends. Subsequently, open the waste gas valve 413 of the first pressure swing adsorption tower 41A, and make most of the remaining flue gas that has completed carbon dioxide adsorption be discharged to the gas storage reservoir 3 through the waste gas port of the first pressure swing adsorption tower 41A. At the same time, open the connection valve between the first pressure swing adsorption tower 41A and the second pressure swing adsorption tower 41B, and make a small part of the remaining flue gas in the first pressure swing adsorption tower 41A enter the second pressure swing adsorption tower 41B to purge the adsorption bed layer in the second pressure swing adsorption tower 41B that has previously completed the carbon dioxide adsorption process, thereby restoring the adsorption capacity of the adsorbent in the second pressure swing adsorption tower 41B. The process of the above remaining flue gas entering the gas storage reservoir 3 and the second pressure swing adsorption tower 41B can be driven by the surplus electric energy generated by the power system. As the gas pressure in the first pressure swing adsorption tower 41A continuously decreases to the desorption pressure, the carbon dioxide in the adsorbent starts to automatically desorb from the adsorbent. At this time, close the waste gas valve 413 of the first pressure swing adsorption tower 41A and open the product gas valve 412 of the first pressure swing adsorption tower 41A, and make the carbon dioxide desorbed from the adsorbent be discharged into the carbon dioxide storage tank 42 for storage through the product gas valve 412 of the first pressure swing adsorption tower 41A.

[0068] After the purging process of a small portion of the remaining flue gas in the first pressure swing adsorption tower 41A above on the adsorption bed of the second pressure swing adsorption tower 41B is completed, open the intake valve 411 of the second pressure swing adsorption tower 41B and close the waste gas valve 413. At the same time, close the intake valve 411 of the first pressure swing adsorption tower 41A to allow the compressed flue gas to flow into the second pressure swing adsorption tower 41B under the drive of pressure. Subsequently, in the second pressure swing adsorption tower 41B, repeat the above processes of carbon dioxide adsorption and desorption, and use a small amount of the remaining flue gas in the second pressure swing adsorption tower 41B to purge the adsorption bed layer in the first pressure swing adsorption tower 41A. Through the continuous staggered circulation of each link in the carbon dioxide capture process by the first pressure swing adsorption tower 41A and the second pressure swing adsorption tower 41B, it is possible to ensure continuous intake and exhaust during the operation of the pressure swing adsorption carbon capture device 4, and it will not affect the continuous and stable operation of other devices in the energy storage system 100.

[0069] In this embodiment, the pressure swing adsorption carbon capture device 4 further includes a pressure stabilizing tank 43, which is arranged between the pressure swing adsorption tower 41 and the gas storage reservoir 3. Refer to Figure 2 , the intake port of the pressure stabilizing tank 43 is connected to the waste gas port of the pressure swing adsorption tower 41, and the exhaust port of the pressure stabilizing tank 43 is connected to the intake port of the gas storage reservoir 3, and is used to maintain the stability of the intake pressure for the gas storage reservoir 3 during the process of mutual switching of the pressure swing adsorption carbon capture device 4 in the above-mentioned flue gas intake, carbon dioxide adsorption / desorption, remaining flue gas exhaust, regeneration gas purging and other stages.

[0070] Figure 2 is a schematic diagram of the operation module of another energy storage system 100 provided in this embodiment. The energy storage system 100 further includes a heat exchange device 6. Refer to Figure 2 , the heat exchange device 6 is arranged between the gas compression device 1 and the gas expansion device 2; refer to Figure 3 , the heat exchange device 6 includes a heat exchanger, a heat storage tank 63, heat exchange tubes (not shown in the figure) and a heat exchange pump (not shown in the figure). Among them, the heat exchanger includes a first heat exchanger 61, a second heat exchanger 62 and a third heat exchanger (not shown in the figure). The first heat exchanger 61 is arranged near the exhaust port of the compressor 11, the second heat exchanger 62 is arranged near the intake port of the turbine 21, and the third heat exchanger is arranged in the pressure swing adsorption tower 41 of the pressure swing adsorption carbon capture device 4; a heat storage medium is arranged inside the heat storage tank 63; the heat exchanger and the heat storage tank 63 are connected by heat exchange tubes, and a heat exchange medium is arranged in the heat exchange tubes; the heat exchange pump is arranged in the heat exchange tubes and is used to drive the heat exchange medium in the heat exchange tubes to circulate between the heat exchanger and the heat storage tank 63.

[0071] Through the above-mentioned setting method of the heat exchange device 6, on the one hand, when the flue gas enters the compressor 11 for gas compression, the heat generated is exchanged with the first heat exchanger 61, reducing the temperature of the compressed flue gas. At this time, the density of the compressed flue gas further increases, so that the mass of the flue gas entering the gas storage reservoir from the gas compression device 1 and stored can be further increased. At the same time, the heat of the compressed flue gas is transferred to the heat exchange medium in the heat exchange tube connected to the first heat exchanger 61 through the first heat exchanger 61. Subsequently, driven by the heat exchange pump, the heated heat exchange medium is transferred from the first heat exchanger 61 to the heat storage tank 63, and the heat is transferred to the heat storage medium in the heat storage tank 63 for storage.

[0072] On the other hand, the heat exchange medium in the heat exchange tube connected to the second heat exchanger 62 is heated by absorbing the heat stored in the heat storage tank 63, and the heated heat exchange medium is transferred to the second heat exchanger 62 by the heat exchange pump, so that the second heat exchanger 62 has a certain temperature. Before the compressed flue gas enters the turbine 21 of the gas expansion device 2, it exchanges heat with the second heat exchanger 62, increasing the temperature of the compressed flue gas, and thus improving the expansion work capacity of the compressed flue gas.

[0073] In addition, the heat exchange medium in the heat exchange tube connected to the third heat exchanger is heated by absorbing the heat stored in the heat storage tank 63, and the heated heat exchange medium is transferred to the third heat exchanger by the heat exchange pump, so that the third heat exchanger has a certain temperature. After the flue gas completes the carbon dioxide adsorption process in the pressure swing adsorption tower 41, the temperature in the pressure swing adsorption tower 41 is increased through the third heat exchanger provided in the pressure swing adsorption tower 41, thereby improving the purging efficiency of the regeneration gas for the adsorption bed layer, accelerating the carbon dioxide desorption speed and promoting the regeneration of the adsorbent.

[0074] In this embodiment, between multiple series-connected compressors 11 and multiple turbines 21, and between multiple parallel-connected pressure swing adsorption towers 41, heat exchange devices such as heat exchangers and heat exchange tubes can be respectively provided, which can not only perform multi-stage heat storage to improve the heat storage efficiency, but also perform multi-stage heating to increase the inlet temperature of the gas expansion device 2, thereby improving the energy storage efficiency of the overall energy storage system 100.

[0075] Through the heat exchange process of the above-mentioned heat exchange device 6, the storage and reuse of the heat of the flue gas are completed, which not only improves the carbon dioxide capture efficiency, but also can further reduce energy consumption and improve the overall operation efficiency of the energy storage system 100.

[0076] This embodiment also provides an operation method, which is applied to the compressed gas energy storage system 100 based on pressure swing adsorption carbon capture, and includes the following execution steps: gas pretreatment step, gas boosting step, gas storage step, gas expansion step, pressure swing adsorption carbon capture step.

[0077] The execution steps in the operation method are described below.

[0078] <Gas pretreatment step>

[0079] A large amount of flue gas discharged during the operation of coal-fired power plants, gas turbine power plants, biomass power plants or industrial boilers, especially power plants with thermal power units, contains a certain proportion of carbon dioxide. When this part of the flue gas is introduced into the energy storage system 100, not only can effective carbon dioxide capture be achieved, but also the excess electric energy generated by the power plant can be stored in the energy storage system 100 using compressed gas energy storage technology for peak shaving. The raw flue gas discharged from the thermal power unit contains impurities such as water vapor, sulfides, nitrides, and dust. To prevent the above impurities from affecting the normal operation of the energy storage system 100 and to extend the service life of the energy storage system 100, the raw flue gas needs to be introduced into the gas pretreatment device 5 for pretreatment to effectively remove the impurities.

[0080] <Gas boosting step>

[0081] The flue gas that has completed the gas pretreatment step is discharged from the gas outlet of the gas pretreatment device 5 and then enters the gas compression device 1 for flue gas compression. In this embodiment, the flue gas compression process is completed by the compressor 11 provided in the gas compression device 1, and the electric energy driving the compressor 11 is provided by the excess electric energy generated by the power system. Through the gas boosting step, the excess electric energy is converted into the pressure energy and thermal energy of the compressed flue gas.

[0082] <Gas storage step>

[0083] After the flue gas has completed the gas boosting step, the compressed flue gas is discharged from the gas compression device 1 and then introduced into the gas storage tank 3 for storage and standby. To enable the compressed flue gas to be more completely transferred from the gas compression device 1 to the gas storage tank 3, the excess electric energy generated by the power system can be used to extract the compressed flue gas in the gas compression device 1.

[0084] <Gas expansion step>

[0085] When the power system needs peak shaving and the energy stored in the energy storage system 100 needs to be used for power supply, the compressed flue gas is discharged from the gas storage tank 3 and then enters the gas expansion device 2 for expansion work. In this embodiment, a turbine 21 is provided in the gas expansion device 2, and the compressed flue gas entering the gas expansion device 2 expands to drive the turbine 21 to generate electricity, thus completing the power peak shaving.

[0086] <Pressure swing adsorption carbon capture step>

[0087] Since the flue gas discharged from a thermal power unit contains a certain proportion of carbon dioxide, to avoid environmental problems such as the greenhouse effect caused by this part of carbon dioxide, in this embodiment, pressure swing adsorption carbon capture is used to adsorb or store carbon dioxide in the gas flowing from the inlet of the gas compression device 1 to the outlet of the gas expansion device 2. In this embodiment, the pressure swing adsorption carbon capture device 4 is arranged between the gas compression device 1 and the gas storage reservoir 3. The outlet of the gas compression device 1 is connected to the inlet of the pressure swing adsorption carbon capture device 4; the pressure swing adsorption carbon capture device 4 is connected to the inlet of the gas storage reservoir 3; the flue gas undergoes carbon dioxide adsorption in the pressure swing adsorption carbon capture device 4, and the carbon dioxide in the flue gas is separated and stored.

[0088] The operation method provided in this embodiment further includes a purging step.

[0089] <Purging step>

[0090] After the pressure swing adsorption carbon capture step is completed, a small part of the remaining flue gas in the multiple pressure swing adsorption towers 41 enters another pressure swing adsorption tower 41 other than itself, serving as a regeneration gas to purge the adsorption bed layer in another pressure swing adsorption tower 41, promoting the desorption of carbon dioxide in the adsorbent and completing the regeneration of the adsorbent.

[0091] For another energy storage system 100 provided in this embodiment, the operation method further includes a heat exchange step.

[0092] <Heat exchange step>

[0093] On the one hand, as the flue gas is compressed in the gas boosting step, a part of the electrical energy is converted into the heat of the compressed flue gas. Through the heat exchange step, the compressed flue gas can be cooled by heat exchange at this time, so that the density of the compressed flue gas increases to enhance the energy storage capacity of the energy storage system 100.

[0094] On the other hand, the heat of the compressed flue gas can be stored through the heat exchange step and reused in the purging step and the gas expansion step. Among them, when the flue gas completes carbon dioxide adsorption in the pressure swing adsorption carbon capture step, the heat stored in the heat exchange step is used to heat the pressure swing adsorption tower 41, so that the regeneration gas in the purging step can more fully purge the adsorption bed layer to complete carbon dioxide desorption and adsorbent regeneration. Before the gas expansion step is carried out, the heat stored in the heat exchange step can continue to be used to heat up the compressed flue gas discharged from the gas storage reservoir 3, improving the expansion work capacity of the heated compressed flue gas.

[0095] <Second embodiment>

[0096] Figure 4 It is a schematic diagram of the operation module of an energy storage system 100 provided in this embodiment. As Figure 4As shown, in this embodiment, the energy storage system 100 includes a gas compression device 1, a gas expansion device 2, a gas storage reservoir 3, a pressure swing adsorption carbon capture device 4, and a gas pretreatment device 5. Different from the first embodiment, in this embodiment, the intake port of the pressure swing adsorption carbon capture device 4 is connected to the exhaust port of the gas storage reservoir 3, and the exhaust port of the pressure swing adsorption carbon capture device 4 is connected to the intake port of the gas expansion device 2.

[0097] In this embodiment, in the charging condition of the energy storage system 100, the external flue gas is input into the gas pretreatment device 5. The gas pretreatment device 5 removes impurities from the flue gas. The pretreated flue gas enters the gas compression device 1, and the gas compression device 1 compresses it to obtain compressed flue gas, which is transported to the gas storage reservoir 3 for storage. In the discharging condition of the energy storage system 100, the compressed flue gas stored in the gas storage reservoir 3 flows into the pressure swing adsorption carbon capture device 4. The pressure swing adsorption carbon capture device 4 captures carbon dioxide from the compressed flue gas. The flue gas after carbon dioxide capture enters the gas expansion device 2, and the gas expansion device 2 expands the flue gas to generate electric energy and transports it to external equipment.

[0098] Figure 5 It is a schematic diagram of the operation module of another energy storage system 100 provided in this embodiment. As Figure 5 shown, the energy storage system 100 further includes a heat exchange device 6. The gas compression device 1 is connected to the intake port of the gas storage reservoir 3 through the heat exchange device 6. The gas expansion device 2 is connected to the exhaust port of the pressure swing adsorption carbon capture device 4 through the heat exchange device 6. The pressure swing adsorption carbon capture device 4 is connected to the heat exchange device 6. Specifically, as Figure 6 shown, the exhaust gas port of the pressure swing adsorption tower 41 is connected to the intake port of the pressure stabilizing tank 43. The exhaust port of the pressure stabilizing tank 43 is connected to the intake port of the gas storage reservoir 3. The compressed flue gas is discharged from the exhaust port of the gas storage reservoir 3 and then passes through the second heat exchanger 62 to the gas expansion device 2 to drive the turbine 21 to generate electricity.

[0099] <Third Embodiment>

[0100] Figure 7 It is a schematic diagram of the operation module of an energy storage system 100 provided in this embodiment. As Figure 7 shown, in this embodiment, the energy storage system 100 includes a gas compression device 1, a gas expansion device 2, a gas storage reservoir 3, a pressure swing adsorption carbon capture device 4, and a gas pretreatment device 5. Different from the first and second embodiments, in this embodiment, the intake port of the pressure swing adsorption carbon capture device 4 is connected to the exhaust port of the compressor 11 except the last stage in the gas compression device 1, and the exhaust port of the pressure swing adsorption carbon capture device 4 is connected to the intake port of the next stage compressor 11 in the gas compression device 1.

[0101] In this embodiment, in the charging condition of the energy storage system 100, the flue gas from the outside is input into the gas pretreatment device 5. The gas pretreatment device 5 removes impurities from the flue gas. The pretreated flue gas enters the gas compression device 1. While the gas compression device 1 compresses it to obtain compressed flue gas, the pressure swing adsorption carbon capture device 4 connected inside the gas compression device 1 captures carbon dioxide from the compressed flue gas. The processed gas after carbon capture enters the gas storage tank 3 for storage. In the discharging condition of the energy storage system 100, the high-pressure processed gas stored in the gas storage tank 3 flows into the gas expansion device 2 to expand and generate electric energy, which is then transmitted to external equipment.

[0102] <Fourth Embodiment>

[0103] Figure 8 It is a schematic diagram of the operation module of an energy storage system 100 provided in this embodiment. As Figure 8 shown, in this embodiment, the energy storage system 100 includes a gas compression device 1, a gas expansion device 2, a gas storage tank 3, a pressure swing adsorption carbon capture device 4, and a gas pretreatment device 5. Different from the first, second, and third embodiments, in this embodiment, the inlet of the pressure swing adsorption carbon capture device 4 is connected to the exhaust port of the expander except the last stage in the gas expansion device 2, and the exhaust port of the pressure swing adsorption carbon capture device 4 is connected to the inlet of the next-stage expander in the gas expansion device 2.

[0104] In this embodiment, in the charging condition of the energy storage system 100, the flue gas from the outside is input into the gas pretreatment device 5. The gas pretreatment device 5 removes impurities from the flue gas. The pretreated flue gas enters the gas compression device 1. After the gas compression device 1 compresses it to obtain compressed flue gas, the compressed flue gas enters the gas storage tank 3 for storage. In the discharging condition of the energy storage system 100, while the compressed flue gas stored in the gas storage tank 3 flows into the gas expansion device 2 to expand and generate electric energy and is transmitted to external equipment, the pressure swing adsorption carbon capture device 4 connected inside the gas expansion device 2 captures carbon dioxide from the compressed flue gas.

[0105] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A compressed gas energy storage system based on pressure swing adsorption carbon capture, characterized in that, Comprising: A gas pretreatment device; A gas compression device, the exhaust port of the gas pretreatment device being connected to the intake port of the gas compression device; A gas storage reservoir, the exhaust port of the gas compression device being connected to the intake port of the gas storage reservoir; A gas expansion device, the exhaust port of the gas storage reservoir being connected to the intake port of the gas expansion device; A pressure swing adsorption carbon capture device, the pressure swing adsorption carbon capture device being arranged between the intake port of the gas compression device and the exhaust port of the gas expansion device.

2. The compressed gas energy storage system based on pressure swing adsorption carbon capture according to claim 1, wherein The pressure swing adsorption carbon capture device comprises: At least two pressure swing adsorption towers, one or more layers of adsorption beds being provided in the pressure swing adsorption towers, an adsorbent being filled in the adsorption beds for adsorbing carbon dioxide in the gas, the adsorbent including one or more combinations of activated carbon, silica gel, molecular sieve, metal organic framework material; A carbon dioxide storage tank, connected to the pressure swing adsorption tower, carbon dioxide desorbed from the adsorbent being introduced into the carbon dioxide storage tank.

3. The compressed gas energy storage system based on pressure swing adsorption carbon capture according to claim 2, wherein The pressure swing adsorption carbon capture device further comprises a pressure stabilizing tank, arranged between the pressure swing adsorption tower and the gas storage reservoir.

4. The compressed gas energy storage system based on pressure swing adsorption carbon capture according to claim 2, wherein The multiple pressure swing adsorption towers of the pressure swing adsorption carbon capture device are arranged in parallel and periodically perform a pressure swing adsorption cycle to continuously produce carbon dioxide into the carbon dioxide storage tank.

5. The compressed gas energy storage system based on pressure swing adsorption carbon capture according to claim 1, wherein The gas pretreatment device includes: A condenser, the raw gas entering the gas pretreatment device through the intake port of the condenser; A desulfurization tower, the exhaust port of the condenser being connected to the intake port of the desulfurization tower; A denitration tower, the exhaust port of the desulfurization tower being connected to the intake port of the denitration tower; A dust collector, the exhaust port of the denitration tower being connected to the intake port of the dust collector, and the exhaust port of the dust collector being connected to the intake port of the gas compression device.

6. The compressed gas energy storage system based on pressure swing adsorption carbon capture according to claim 1, wherein The gas compression device includes multiple compressors connected in series, the intake port of one of the compressors being connected to the exhaust port of the gas pretreatment device, and the exhaust port of another compressor being connected to the intake port of the gas storage reservoir; and / or, The gas expansion device includes multiple turbines connected in series, the compressed gas entering the gas expansion device driving the turbines to generate electricity, the intake port of one of the turbines being connected to the exhaust port of the gas storage reservoir, and the exhaust port of another turbine discharging the remaining gas that has completed expansion work to the outside.

7. The compressed gas energy storage system based on pressure swing adsorption carbon capture according to claim 6, wherein It further includes a heat exchange device, the heat exchange device being arranged between the gas compression device and the gas expansion device; The heat exchange device includes: A heat exchanger, arranged near the exhaust port of the compressor and the intake port of the turbine, and inside the pressure swing adsorption tower of the pressure swing adsorption carbon capture device; A heat storage tank, a heat storage medium being arranged inside the heat storage tank; A heat exchange pipe, the heat exchanger and the heat storage tank being connected by the heat exchange pipe, a heat exchange medium being arranged inside the heat exchange pipe; A heat exchange pump, arranged inside the heat exchange pipe, driving the heat exchange medium in the heat exchange pipe to circulate between the heat exchanger and the heat storage tank.

8. An operating method of a compressed gas energy storage system based on pressure swing adsorption carbon capture according to any one of claims 1 to 7, characterized in that, Including the following steps: Gas pretreatment step: The gas to be treated enters the gas pretreatment device for pretreatment; Gas boosting step: The pretreated gas entering the gas compression device from the gas pretreatment device is boosted in pressure; Gas storage step: The compressed gas entering the gas storage reservoir from the gas compression device is stored; Gas expansion step: The compressed gas entering the gas expansion device from the gas storage reservoir performs expansion work; Pressure swing adsorption carbon capture step: Carbon dioxide in the gas flowing from the inlet of the gas compression device to the outlet of the gas expansion device is subjected to pressure swing adsorption or storage.

9. The operating method according to claim 8, characterized in that The gas boosting step and the gas storage step are driven by the excess power generated by the generator set, and the gas expansion step uses gas expansion to drive a turbine to generate electricity; the pressure swing adsorption carbon capture device in the pressure swing adsorption carbon capture step uses the heat energy or air energy generated by the compressed gas to increase the adsorption capacity of the adsorbent for carbon dioxide.

10. The operating method according to claim 8, characterized in that, It further includes: Purge step: After the pressure swing adsorption carbon capture step is completed, the remaining gas in multiple pressure swing adsorption towers enters another pressure swing adsorption tower other than itself to purge and regenerate the adsorbent in the other pressure swing adsorption tower. Heat exchange step: For: Cooling the compressed gas generated by the gas boosting step through heat exchange; Heating the compressed gas before the gas expansion step through heat exchange; and Heating the pressure swing adsorption tower after the pressure swing adsorption carbon capture step is completed through heat exchange.

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