Air carbon capture system coupled with compressed air energy storage

Abstract

The utility model discloses an air carbon capture system coupled with compressed air energy storage. The air carbon capture system comprises a compressed air energy storage system, a heat recovery system and an air carbon capture system, the compressed air energy storage system comprises a multi-stage air compression device, a compressed air storage facility and an air turbine unit; the air carbon capture system comprises a CO2 adsorption-desorption reactor and a CO2 storage tank; the CO2 adsorption-desorption reactor is arranged between two certain stages of compressors of the multi-stage air compression device; the heat recovery system comprises a heat storage tank and a normal-temperature tank. According to the invention, the air carbon capture system is coupled with the compressed air energy storage system, so that the adverse effect of water vapor in air on the selectivity and adsorption capacity of the adsorption material can be reduced, and compared with the traditional direct air carbon capture system, the air capture energy consumption is reduced, the CO2 desorption energy consumption can be reduced, and the energy utilization efficiency is improved.

Description

Technical Field

[0001] This utility model relates to an air carbon capture system coupled with compressed air energy storage, belonging to the field of carbon dioxide capture technology. Background Technology

[0002] Industrial development has led to the combustion of large quantities of fossil fuels, exacerbating CO2 emissions. Globally, CO2 emissions from fossil fuel combustion exceed 35 billion tons annually. Nearly 50% of global CO2 emissions originate from distributed sources. Distributed sources, such as small and medium-sized boiler flue gas, industrial exhaust, and vehicle exhaust, are characterized by small individual emissions, wide distribution, and large numbers. Distributed sources have a large base of CO2 emissions, with atmospheric CO2 having the largest stockpile, but it is also the most difficult to capture due to its lowest concentration. Direct Air Capture (DAC) is a technology that directly captures and obtains high-concentration CO2 from the air, with the potential to address CO2 emissions from distributed sources, providing a solution for sectors where emission reduction is difficult in the short term (such as long-distance transportation and the chemical industry).

[0003] The main technical routes for direct carbon capture (DAC) include chemical absorption, solid-state adsorption, and humidified adsorption. Chemical absorption typically uses alkaline solutions such as NaOH and Ca(OH)₂ to absorb carbon dioxide from the air, and then calcines the precipitated carbonates to obtain the product gas. Its disadvantages include: calcination temperatures exceeding 800℃ during regeneration, water consumption during adsorption, and high energy consumption. Compared to solution absorption, solid-state adsorption technology has a more suitable regeneration temperature, ranging from 80-150℃, avoiding the high latent heat of heating the absorbent and offering significant advantages in reducing equipment corrosion and degradation. Humidified adsorption drives the adsorption / desorption of the adsorbent through changes in temperature and humidity, but for rapid industrial applications, its technological maturity is not as high as solid-state adsorption and chemical absorption. Therefore, solid-state adsorption is a more widely adopted and feasible technical route in the field of direct air carbon capture.

[0004] Because the partial pressure of CO2 in the air is low (40 Pa) and its volume fraction is low (4.2 × 10⁻⁶ Pa), it is difficult to detect CO2 in the air. -4 Existing solid adsorption technologies still face challenges such as high actual capture costs, high energy consumption in the air capture and CO2 regeneration stages, and immature capture devices and processes. Furthermore, for common physical adsorption materials such as zeolite molecular sieves and metal-organic frameworks, water vapor in the air negatively impacts the selectivity and adsorption capacity of these materials; adding air dehumidification equipment further increases equipment costs and system energy consumption. Therefore, how to fully utilize waste heat, low-grade heat sources, and renewable energy to optimize the DAC process and reduce DAC system energy consumption and overall costs is a technical problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0005] The purpose of this invention is to address the problems of low CO2 partial pressure in the air, high energy consumption and cost of DAC technology, and the significant impact of air humidity on the adsorption effect of adsorbents. The invention aims to develop an air carbon capture system coupled with compressed air energy storage, thereby reducing the blower energy consumption and regeneration energy consumption of the DAC system, minimizing the impact of moisture on the adsorption effect of the adsorbent, and improving energy utilization efficiency.

[0006] To achieve the above-mentioned technical objectives and effects, this application provides the following technical solution:

[0007] This invention provides an air carbon capture system coupled with compressed air energy storage, comprising a compressed air energy storage system, a heat recovery system, and an air carbon capture system. The compressed air energy storage system includes a multi-stage air compressor, compressed air storage facilities, and an air turbine unit. The multi-stage air compressor has multiple interconnected single-stage compressors. The air carbon capture system includes a CO2 adsorption-desorption reactor and a CO2 storage tank. The CO2 adsorption-desorption reactor has an internal air channel and a heat storage medium channel. The heat recovery system includes a heat storage tank and an ambient temperature tank. The CO2 adsorption-desorption reactor is positioned between any two compressor stages of the multi-stage air compressor. The air channel inlet of the CO2 adsorption-desorption reactor is connected to the outlet of the preceding compressor stage, and the air channel outlet is distributed via a bypass. The multi-stage air compressor is not connected to the inlet of the next stage compressor, the inlet of the CO2 storage tank, or the atmosphere; the outlet of the multi-stage air compressor is connected to the inlet of the compressed air storage facility, and the outlet of the compressed air storage facility is connected to the inlet of the air turbine unit; the outlet of the air turbine unit is connected to the atmosphere and also connected to the air channel inlet of the CO2 adsorption-desorption reactor via a bypass; the inlet of the heat storage tank is connected to the heat storage medium outlet of both the multi-stage air compressor and the CO2 adsorption-desorption reactor, and the outlet of the heat storage tank is connected to the heat storage medium inlet of both the air turbine unit and the CO2 adsorption-desorption reactor; the inlet of the ambient temperature tank is connected to the heat storage medium channel outlet of the air turbine unit, and the outlet of the ambient temperature tank is connected to the heat storage medium inlet of the multi-stage air compressor; at least one valve is provided between each bypass for switching.

[0008] Preferably, the heat storage medium in the heat storage tank and the ambient temperature tank includes, but is not limited to, water, heat transfer oil or molten salt.

[0009] Preferably, the multi-stage air compression device includes 2-5 stages of compressors, and at least one CO2 adsorption-desorption reactor is provided. When multiple CO2 adsorption-desorption reactors are provided, the multiple CO2 adsorption-desorption reactors are respectively arranged between any two interconnected stages of compressors; when a single CO2 adsorption-desorption reactor is provided, the CO2 adsorption-desorption reactor is arranged between any two stages of compressors.

[0010] Preferably, the air channel of the CO2 adsorption-desorption reactor is filled with CO2 adsorption material, which can be a physical adsorbent such as activated carbon or zeolite, or a chemical adsorbent such as solid amine.

[0011] The air carbon capture system coupled with compressed air energy storage provided by this utility model has the following advantages:

[0012] 1. This utility model utilizes the high-pressure air generated during the compression process in the compressed air energy storage system as the air source for the air carbon capture system, thereby reducing the energy consumption and cost of the blower in the traditional direct air carbon capture system; and by increasing the partial pressure of CO2 in the air, it reduces the energy consumption of the adsorption process.

[0013] 2. This utility model utilizes the compression process in the compressed air energy storage system to remove moisture from the air, effectively reducing the adverse effects of water vapor in the air on the selectivity and adsorption capacity of CO2.

[0014] 3. This utility model utilizes a portion of the compression heat recovered during the compression process of the compressed air energy storage system for the desorption process of the air carbon capture system, thereby reducing CO2 desorption energy consumption and improving energy utilization efficiency. Attached Figure Description

[0015] Figure 1 A schematic diagram of the composition of an air carbon capture system coupled with compressed air energy storage provided for an embodiment of this utility model;

[0016] In the picture:

[0017] 1-Multi-stage air compression device; 1a-Second-stage air compressor; 1b-Third-stage air compressor; 2-Compressed air storage facility; 3-Air turbine unit; 4-CO2 adsorption-desorption reactor; 5-CO2 storage tank; 6-Heat storage tank; 7-Ambient temperature tank. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0019] Reference Figure 1 This utility model provides an air carbon capture system coupled with compressed air energy storage, including a compressed air energy storage system, a heat recovery system and an air carbon capture system.

[0020] The compressed air energy storage system includes a multi-stage air compressor 1, a compressed air storage facility 2, and an air turbine unit 3. The multi-stage air compressor has 2-5 interconnected single-stage compressors. In this embodiment, the multi-stage air compressor 1 preferably includes a 3-stage compressor for pressurizing air in stages. An air carbon capture system is installed in series between the second-stage air compressor 1a and the third-stage air compressor 1b of the multi-stage air compressor 1. In this embodiment, the installation and use of the multi-stage air compressor 1 composed of multiple compressors is prior art and will not be described in detail.

[0021] The air carbon capture system includes a CO2 adsorption-desorption reactor 4 and a CO2 storage tank 5. The CO2 adsorption-desorption reactor 4 has an air channel and a heat storage medium channel. The air channel is filled with molecular sieves, a CO2 adsorption material, to adsorb CO2 from the high-pressure air supplied by the multi-stage air compressor 1. The CO2 adsorption material can be a physical adsorbent such as activated carbon or zeolite, or a chemical adsorbent such as solid amine. The air channel inlet of the CO2 adsorption-desorption reactor 4 is connected to the outlet of the second-stage air compressor 1a, and the air channel outlet is connected to the third-stage air compressor 1a via a bypass. The inlet of air compressor 1b and the inlet of CO2 storage tank 5 are connected to the atmosphere. The outlet of multi-stage air compression unit 1 is connected to the inlet of compressed air storage facility 2 for storing high-pressure lean CO2 air. The outlet of compressed air storage facility 2 is connected to the inlet of air turbine unit 3, and the outlet of air turbine unit 3 is connected to the atmosphere. It is also connected to the air channel inlet of CO2 adsorption-desorption reactor 4 via a bypass. During the energy release stage, high-pressure air enters air turbine unit 3 to generate electricity. After energy release, part of the air is discharged into the atmosphere, and part of it enters CO2 adsorption-desorption reactor 4 via a bypass to cool the adsorption material. Several valves are installed between the outlets of CO2 adsorption-desorption reactor 4 and air turbine unit 3 for switching, and the operation of the system is controlled by adjusting the gas flow direction.

[0022] The heat recovery system includes a heat storage tank 6 and an ambient temperature tank 7. The inlet of the heat storage tank 6 is connected to the heat storage medium outlet of the multi-stage air compressor 1 and the CO2 adsorption-desorption reactor 4, respectively, for storing the heated heat storage medium and recovering the heat of compression generated during the air compression process. The outlet of the heat storage tank 6 is connected to the heat storage medium inlet of the air turbine unit 3 and the CO2 adsorption-desorption reactor 4, respectively, for heating the CO2 adsorption-desorption reactor 4 during the CO2 desorption process and heating the compressed air during the compressed air energy release stage. The inlet of the ambient temperature tank 7 is connected to the heat storage medium channel outlet of the air turbine unit 3, and the outlet of the ambient temperature tank 7 is connected to the heat storage medium inlet of the multi-stage air compressor 1, for storing the ambient temperature heat storage medium after heat exchange. The heat storage medium in the heat storage tank 6 and the ambient temperature tank 7 includes, but is not limited to, water, heat transfer oil or molten salt. In this embodiment, the heat storage medium in the heat recovery system is preferably water.

[0023] This utility model takes an air carbon capture system with a capture capacity of 1000 tons / year coupled with 300MW compressed air energy storage as an example. The working process is as follows:

[0024] The CO2 adsorption process is part of the energy storage stage of the compressed air energy storage system. Air is pressurized in three stages (0.7 MPa, 5 MPa, and 12 MPa) by a multi-stage air compressor 1. A CO2 adsorption-desorption reactor 4, located between the second-stage air compressor 1a and the third-stage air compressor 1b, adsorbs CO2 from the air coming from the second-stage air compressor 1a. The capture efficiency of the CO2 adsorption-desorption reactor 4 is 60%-70%. The air, after CO2 removal, is recompressed by the third-stage compressor and then stored in the compressed air storage facility 2. The heat storage medium in the ambient temperature tank 7 enters the multi-stage compressor 1 to recover the heat of compression and then enters the heat storage tank 6 to achieve heat recovery and storage. The heat storage medium is water, and the storage temperature is 180-220℃.

[0025] The CO2 desorption process occurs between the end of energy storage and the start of energy release in the compressed air energy storage system. The high-temperature heat storage medium in the heat storage tank 6 enters the heat storage medium channel of the CO2 adsorption-desorption reactor 4 to heat the reactor to 80-140°C. After the reactor is heated, the CO2 desorption process will occur, and the desorbed CO2 will enter the CO2 storage tank 5 for storage.

[0026] The reactor cooling process occurs during the energy release phase of the compressed air energy storage system. High-pressure air from the compressed air storage facility 2 enters the air turbine unit 3, and the heat storage medium in the heat recovery system is used to heat the air to improve power generation efficiency. The rated power of the unit is 300MW. The exhaust temperature of the air turbine unit 3 is 50℃. Part of the exhaust is directly discharged into the atmosphere, while the other part bypasses into the CO2 adsorption-desorption reactor 4 to cool the reactor heated during the desorption process, ensuring the normal operation of the reactor in the next adsorption stage. The air after cooling the reactor is finally discharged into the atmosphere.

[0027] The above description is merely a preferred embodiment of this utility model and is not intended to limit this utility model in any form or substance. It should be noted that those skilled in the art can make various improvements and additions without departing from this utility model, and these improvements and additions should also be considered within the protection scope of this utility model. Any modifications, alterations, and equivalent changes made by those skilled in the art without departing from the spirit and scope of this utility model using the disclosed technical content are equivalent embodiments of this utility model. Furthermore, any modifications, alterations, and evolutions made to the above embodiments based on the essential technology of this utility model are still within the scope of the technical solution of this utility model.

Claims

1. An air carbon capture system coupled to compressed air energy storage, characterized in that, The system comprises a compressed air energy storage system, a heat recovery system and an air carbon capture system; the compressed air energy storage system comprises a multi-stage air compressor device (1), a compressed air storage facility (2) and an air turbine unit (3), the multi-stage air compressor device (1) has a plurality of single-stage compressors in communication with each other; the air carbon capture system comprises a CO2 adsorption-desorption reactor (4) and a CO2 storage tank (5), the CO2 adsorption-desorption reactor (4) is internally provided with an air passage and a heat storage medium passage; the heat recovery system comprises a heat storage tank (6) and a normal temperature tank (7); the CO2 adsorption-desorption reactor (4) is arranged between any two-stage compressors of the multi-stage air compressor device (1), the air passage inlet of the CO2 adsorption-desorption reactor (4) is connected with the outlet of the upper-stage compressor, the air passage outlet is connected with the inlet of the lower-stage compressor, the inlet of the CO2 storage tank (5) and the atmosphere through bypasses respectively; the outlet of the multi-stage air compressor device (1) is connected with the inlet of the compressed air storage facility (2), the outlet of the compressed air storage facility (2) is connected with the inlet of the air turbine unit (3); the outlet of the air turbine unit (3) is connected with the atmosphere and the air passage inlet of the CO2 adsorption-desorption reactor (4) through bypasses; the heat storage medium outlets of the multi-stage air compressor device (1) and the CO2 adsorption-desorption reactor (4) are connected with the heat storage tank (6) inlet respectively, the heat storage medium inlets of the air turbine unit (3) and the CO2 adsorption-desorption reactor (4) are connected with the heat storage tank (6) outlet respectively; the heat storage medium passage outlet of the air turbine unit (3) is connected with the inlet of the normal temperature tank (7), the heat storage medium inlet of the multi-stage air compressor device (1) is connected with the outlet of the normal temperature tank (7); at least one valve is arranged between the bypasses for switching.

2. An air carbon capture system coupled with compressed air energy storage of claim 1, wherein, The heat storage medium in the heat storage tank (6) and the normal temperature tank (7) comprises but is not limited to water, heat-conducting oil or molten salt.

3. An air carbon capture system coupled with compressed air energy storage of claim 1, wherein, The multi-stage air compressor device (1) comprises 2-5 stage compressors, the CO2 adsorption-desorption reactor (4) is arranged at least one, when a plurality of CO2 adsorption-desorption reactors (4) are arranged, the plurality of CO2 adsorption-desorption reactors (4) are arranged between any two-stage compressors in communication with each other; when a single CO2 adsorption-desorption reactor (4) is arranged, the CO2 adsorption-desorption reactor (4) is arranged between any two-stage compressors.

4. An air carbon capture system coupled with compressed air energy storage of claim 1, wherein, The air passage of the CO2 adsorption-desorption reactor (4) is filled with CO2 adsorption material, the CO2 adsorption material is physical adsorbent activated carbon, zeolite or chemical adsorbent solid amine.

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