Carbon dioxide storage and release system combined with carbon capture and method of controlling the same

Abstract

The application discloses a carbon dioxide energy storage system combined with carbon capture and a control method thereof. The carbon dioxide energy storage system comprises a carbon capture subsystem and an energy storage subsystem. A gas output pipeline of the carbon capture subsystem is coupled to a gas storage unit of the energy storage subsystem, and the captured carbon dioxide gas is used as a circulating working medium of the energy storage subsystem. A lean liquid conveying pipeline in the carbon capture subsystem is coupled to an energy release unit of the energy storage subsystem, so that the lean liquid with residual heat output from a desorption tower is used as a heat source to evaporate and gasify liquid carbon dioxide input into the energy release unit and reduce the temperature of the lean liquid to improve absorption efficiency. A rich liquid conveying pipeline in the carbon capture subsystem is coupled to a heat circulation unit of the energy storage subsystem, so that a high-temperature heat circulation medium in the heat circulation unit is used as a heat source to heat and warm the rich liquid in the rich liquid conveying pipeline to improve desorption efficiency. The scheme of the application can improve the overall energy efficiency of the system and reduce the cost.

Description

Technical Field

[0001] This invention relates to the field of comprehensive energy utilization technology, and in particular to a carbon dioxide energy storage system combined with carbon capture and its control method. Background Technology

[0002] Currently, global climate change is becoming increasingly prominent, and reducing greenhouse gas emissions, especially carbon dioxide (CO2), has become an international consensus. Among numerous emission reduction methods, carbon capture, utilization, and storage (CCUS) technology has shown great potential. However, traditional amine absorption carbon capture technology faces application challenges due to its high energy consumption. Meanwhile, energy storage technology based on carbon dioxide gas-liquid phase change cycle (CCUS) utilizes surplus electricity or clean energy during off-peak hours to compress and condense gaseous carbon dioxide at room temperature and pressure into liquid carbon dioxide, which is then stored in a tank. The heat generated during compression is stored. During peak electricity demand, the stored heat is used to heat the liquid carbon dioxide back to a gaseous state. The gaseous carbon dioxide drives a turbine to generate electricity, and the gaseous carbon dioxide, after performing work, returns to the storage tank for reuse. This technology, with its advantages of simple structure, flexible layout, and high energy storage efficiency, has gradually attracted widespread attention.

[0003] Carbon sequestration and capture (CFS) and carbon dioxide energy storage both use carbon dioxide as the working medium and have some matching operating parameters. How to combine CFS with carbon dioxide energy storage to further improve carbon utilization and achieve comprehensive and effective resource utilization is a problem that needs to be explored and solved. Currently, there are no reports on schemes combining amine absorption CFS with carbon dioxide phase change energy storage. Summary of the Invention

[0004] In view of this, the present invention provides a carbon dioxide energy storage system and its control method combined with carbon capture, which combines amine absorption carbon capture with carbon dioxide phase change energy storage to solve the problem of how to further improve carbon utilization and achieve comprehensive and effective utilization of resources.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A carbon dioxide energy storage system combined with carbon capture, comprising:

[0007] The carbon capture subsystem includes an absorption tower and a desorption tower that are circulated and connected through a lean liquid delivery pipeline and a rich liquid delivery pipeline, and also includes a gas output pipeline connected to the desorption tower.

[0008] The energy storage subsystem includes a gas storage unit, an energy storage unit, a liquid storage unit, and an energy release unit connected in a closed loop in sequence, and also includes a heat circulation unit connected between the energy storage unit and the energy release unit;

[0009] The gas output pipeline is coupled to the gas storage unit, and is used for transporting the carbon dioxide gas captured by the carbon capture subsystem to the gas storage unit as a circulating working medium of the energy storage subsystem, and multiplexing the energy storage unit as a compression-condensation assembly of the carbon capture subsystem to output liquid carbon dioxide for sequestration.

[0010] The lean liquid delivery pipeline is coupled to the energy release unit, and uses the lean liquid with residual heat output from the desorption tower as a heat source to evaporate and gasify the liquid carbon dioxide input to the energy release unit.

[0011] The rich liquid delivery pipeline is coupled to the heat circulation unit, and uses the high-temperature heat circulation medium in the heat circulation unit as a heat source to heat and warm the rich liquid in the rich liquid delivery pipeline.

[0012] In one specific scheme, the carbon capture subsystem further comprises a lean-rich liquid heat exchanger, the lean liquid delivery pipeline comprises a first lean liquid pipeline, a second lean liquid pipeline and a third lean liquid pipeline, and the rich liquid delivery pipeline comprises a first rich liquid pipeline, a second rich liquid pipeline, a third rich liquid pipeline and a rich liquid heat exchanger; wherein,

[0013] The first lean liquid pipeline is connected between the desorption tower and the lean-rich liquid heat exchanger, the second lean liquid pipeline is connected between the lean-rich liquid heat exchanger and the energy release unit, and the third lean liquid pipeline is connected between the energy release unit and the absorption tower; the first rich liquid pipeline is connected between the absorption tower and the lean-rich liquid heat exchanger, the second rich liquid pipeline is connected between the lean-rich liquid heat exchanger and the rich liquid heat exchanger, the third rich liquid pipeline is connected between the rich liquid heat exchanger and the desorption tower, and the rich liquid heat exchanger is coupled to the heat circulation unit.

[0014] In one specific scheme, the energy release unit is provided with an evaporator, the second lean liquid pipeline is connected between the lean-rich liquid heat exchanger and the evaporator, and the third lean liquid pipeline is connected between the evaporator and the absorption tower.

[0015] In one specific scheme, a fourth lean liquid pipeline is connected between the second lean liquid pipeline and the third lean liquid pipeline, and a cooler is arranged on the fourth lean liquid pipeline, which is used to cool the lean liquid in the second lean liquid pipeline and then deliver the cooled lean liquid to the absorption tower through the third lean liquid pipeline.

[0016] In one specific scheme, a lean liquid pump is arranged on the first lean liquid pipeline, and a rich liquid pump is arranged on the first rich liquid pipeline.

[0017] In one specific embodiment, a gas purification treatment unit is arranged on the gas output pipeline, and the gas purification treatment unit is used to purify the carbon dioxide gas output from the desorption tower before being delivered to the gas storage unit.

[0018] In one specific embodiment, an energy storage heat exchanger is arranged in the energy storage unit, an energy release heat exchanger is arranged in the energy release unit, and the heat circulation unit comprises a heat storage container, a cold storage container, a first connecting pipeline, a second connecting pipeline, a third connecting pipeline, a fourth connecting pipeline, a fifth connecting pipeline, and a sixth connecting pipeline; wherein,

[0019] The first connecting pipeline is connected between the cold storage container and the energy storage heat exchanger, the second connecting pipeline is connected between the energy storage heat exchanger and the heat storage container, the third connecting pipeline is connected between the heat storage container and the energy release heat exchanger, the fourth connecting pipeline is connected between the energy release heat exchanger and the cold storage container, the fifth connecting pipeline is connected between the heat storage container and the rich liquid heat exchanger, and the sixth connecting pipeline is connected between the rich liquid heat exchanger and the cold storage container.

[0020] In one specific embodiment, the fourth connecting pipeline is connected between the energy release heat exchanger and the rich liquid heat exchanger, and the heat circulation medium after heat exchange in the energy release unit is delivered to the cold storage container in sequence via the rich liquid heat exchanger and the sixth connecting pipeline.

[0021] Another aspect of the present application is to provide a control method of the carbon dioxide energy storage system combined with carbon capture as described above, comprising:

[0022] controlling the lean liquid in the absorption tower to absorb carbon dioxide in the industrial flue gas to form rich liquid, and delivering the rich liquid to the desorption tower through the rich liquid delivery pipeline;

[0023] controlling the desorption tower to desorb the rich liquid to obtain lean liquid and carbon dioxide gas, delivering the lean liquid to the absorption tower through the lean liquid delivery pipeline, and delivering the carbon dioxide gas to the gas storage unit through the gas output pipeline;

[0024] in the energy storage stage, controlling the energy storage unit to compress and liquefy the carbon dioxide gas in the gas storage unit to form liquid carbon dioxide and deliver it to the liquid storage unit; wherein the low-temperature heat circulation medium in the heat circulation unit absorbs and stores the heat generated by compressing the carbon dioxide gas in the energy storage unit;

[0025] In the energy releasing stage, the energy releasing unit is controlled to evaporate and gasify the liquid carbon dioxide in the liquid storage unit, and to heat and expand the gasified carbon dioxide to work externally, forming carbon dioxide gas to be delivered to the gas storage unit; wherein the lean liquid with residual heat output from the desorption tower is used as a heat source to evaporate and gasify the liquid carbon dioxide input to the energy releasing unit; and the high-temperature heat circulating medium in the heat circulating unit is used as a heat source to heat and expand the gasified carbon dioxide.

[0026] The high-temperature heat circulating medium in the heat circulating unit is used as a heat source to heat the rich liquid in the rich liquid delivery pipeline to be delivered to the desorption tower.

[0027] In one specific scheme, in the energy releasing stage, the heat circulating medium after heat exchange in the energy releasing unit is subjected to heat exchange with the rich liquid in the rich liquid delivery pipeline, so that the heat circulating medium is further reduced in temperature to be delivered to the heat circulating unit.

[0028] The carbon dioxide energy storage system combined with carbon capture and the control method thereof provided by the embodiments of the present application comprise an amine absorption method-based carbon capture subsystem and a carbon dioxide phase change-based energy storage subsystem coupled with each other, and have the following beneficial effects compared with the prior art:

[0029] (1) The gas output pipeline of the carbon capture subsystem is coupled to the gas storage unit of the energy storage subsystem, and the captured carbon dioxide gas is used as the circulating working medium of the energy storage subsystem, and the energy storage unit of the energy storage subsystem is reused as the compression and condensation assembly of the carbon capture subsystem to output liquid carbon dioxide for sequestration. In this way, on the one hand, the low-pressure carbon dioxide gas produced by the carbon capture subsystem can be directly stored in the gas storage unit, and the gas storage unit of the energy storage subsystem is usually provided with a large-volume gas storage bin to store a large amount of low-pressure carbon dioxide gas, which reduces the continuous production requirement of the downstream equipment in the traditional independent carbon capture system, balances the contradiction between continuous absorption and intermittent compression, and performs compression during off-peak electricity, thereby significantly reducing the operation cost of the compressor, improving the carbon utilization efficiency and economic benefit. On the other hand, in the traditional independent carbon capture system, the carbon dioxide gas separated by carbon capture needs to be pressurized by a compressor, cooled by a heat exchanger, and liquefied and condensed before being sequestrated; and in the traditional independent carbon dioxide energy storage system, the carbon dioxide gas also needs to be pressurized by a compressor, cooled by a heat exchanger, and liquefied and condensed in the energy storage stage, and the two have significant commonality. Therefore, the energy storage unit of the energy storage subsystem is reused as the compression and condensation assembly of the carbon capture subsystem, and one set of energy storage process is adopted, so that carbon sequestration and energy storage are completed at the same time, and the investment cost of the carbon capture subsystem is reduced.

[0030] (2), the lean liquid conveying pipeline in the carbon capture subsystem is coupled to the energy releasing unit of the energy storage subsystem, and the lean liquid with residual heat output from the desorption tower is used as a heat source to evaporate and gasify liquid carbon dioxide input to the energy releasing unit. In a traditional independent carbon capture system, the lean liquid output from the desorption tower is still high in temperature (usually 60-70 DEG C) after heat exchange in a lean-liquid rich-liquid heat exchanger, and needs to be cooled (usually to below 40 DEG C) by introducing an external cold source before being conveyed to the absorption tower. In the carbon dioxide energy storage system of the present application, the lean liquid conveying pipeline is coupled to the energy releasing unit of the energy storage subsystem, and the lean liquid with residual heat is used as a heat source to evaporate and gasify liquid carbon dioxide in the energy releasing stage, thereby realizing evaporation and gasification of liquid carbon dioxide and reducing the temperature of the lean liquid to improve the absorption efficiency of the lean liquid in the absorption tower. Therefore, the dependence of the carbon capture subsystem on external energy (cold source) is reduced, the dependence of the energy storage subsystem on external energy (evaporation heat source) is reduced, internal energy circulation is better realized, the overall energy efficiency of the system is greatly improved, and the cost is reduced.

[0031] (3), the rich liquid conveying pipeline in the carbon capture subsystem is coupled to the heat circulation unit of the energy storage subsystem, and the high-temperature heat circulation medium in the heat circulation unit is used as a heat source to heat and warm the rich liquid in the rich liquid conveying pipeline. In the amine method carbon capture process, amine adsorption liquid regeneration heating (heating the rich liquid before being re-conveyed to the desorption tower to make carbon dioxide gas fully desorbed from the amine adsorption liquid) is the most energy-consuming link, and an external heat source usually needs to be provided to heat the rich liquid before being conveyed to the desorption tower. In the carbon dioxide energy storage system of the present application, the compressor is driven by low-price electricity during off-peak electricity period to compress carbon dioxide gas into high-pressure liquid for storage, the heat generated in the compression process is absorbed and stored by the heat circulation unit, and the stored heat is used for the heating step of amine adsorption liquid regeneration, thereby better realizing internal energy circulation, reducing the energy consumption of the carbon capture link, further optimizing energy utilization efficiency, and reducing cost.

[0032] In summary of the above aspects, the carbon dioxide energy storage system in the present application combines the carbon capture subsystem based on the amine absorption method and the energy storage subsystem based on the phase change of carbon dioxide to construct a coordinated circulation system of material flow (carbon dioxide working medium) and energy flow (thermal energy), and the two systems complement each other to simultaneously realize the dual benefits of improving energy utilization efficiency and reducing the energy consumption of the carbon capture process, thereby greatly reducing production cost. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is a structural schematic diagram of the carbon dioxide energy storage system combined with carbon capture according to an embodiment of the present application;

[0034] Figure 2 is a specific connection structure diagram of the carbon capture subsystem according to an embodiment of the present application;

[0035] Figure 3 is a specific connection structure diagram of the energy storage subsystem of the embodiment of the present application. DETAILED DESCRIPTION

[0036] In order to make the objects, technical solutions and advantages of the present application clearer, the specific embodiments of the present application are described in detail below with reference to the drawings. The examples of these preferred embodiments are illustrated in the drawings. The embodiments of the present application shown in the drawings and described according to the drawings are merely exemplary, and the present application is not limited to these embodiments.

[0037] It should be noted that the same or similar reference numerals in the drawings of the embodiments of the present application correspond to the same or similar components; in the description of the present application, it should be understood that if the orientations or positional relationships indicated by the terms "upper", "lower", "left", "right" and the like are based on the orientations or positional relationships shown in the drawings, they are merely for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore, the terms describing the positional relationships in the drawings are used only for exemplary illustration, and cannot be understood as a limitation on the present patent, for those skilled in the art, the specific meanings of the above terms can be understood according to the specific circumstances.

[0038] Here, it should also be noted that, in order to avoid obscuring the present application due to unnecessary details, only the structures and / or processing steps closely related to the scheme according to the present application are shown in the drawings, and other details not closely related to the present application are omitted.

[0039] The embodiments of the present application first provide a carbon dioxide energy storage system combined with carbon capture, referring to Figures 1 to 3 The carbon dioxide energy storage system mainly comprises a carbon capture subsystem 1 and an energy storage subsystem 2.

[0040] As shown in Figure 1 and Figure 2 , the carbon capture subsystem 1 is a carbon capture process using amine absorption method, and mainly comprises an absorption tower 13 and a desorption tower 14 which are cyclically connected through a lean liquid conveying pipeline 11 and a rich liquid conveying pipeline 12, and further comprises a gas output pipeline 15 connected to the desorption tower 14. The lean liquid absorbs carbon dioxide in the industrial flue gas A1 in the absorption tower 13 to form the rich liquid, the rich liquid is conveyed to the desorption tower 14 through the rich liquid conveying pipeline 12, and the flue gas A2 after absorption and purification is discharged from the top of the absorption tower 13. The desorption tower 14 desorbs the rich liquid to form lean liquid and carbon dioxide gas, the carbon dioxide gas is output through the gas output pipeline 15, and the lean liquid is conveyed back to the absorption tower 13 through the lean liquid conveying pipeline 11 to reabsorb carbon dioxide in the industrial flue gas.

[0041] It should be noted that the lean liquid refers to the regenerated amine adsorption liquid after desorption in the desorption tower 14, and the rich liquid refers to the amine adsorption liquid after adsorbing carbon dioxide gas in the absorption tower 13.

[0042] As a specific case, in the embodiment, as shown in Figure 2 The lean-rich liquid heat exchanger 16 is coupled to each other by the lean liquid conveying pipeline 11 and the rich liquid conveying pipeline 12, and the rich liquid output from the absorption tower 13 and the lean liquid output from the desorption tower 14 are heat exchanged through the lean-rich liquid heat exchanger 16, on the one hand, to increase the temperature of the rich liquid before being conveyed to the desorption tower 14 to improve the desorption efficiency, and on the other hand, to reduce the temperature of the lean liquid before being conveyed to the absorption tower 13 to improve the absorption efficiency.

[0043] As shown in Figure 1 and Figure 3 The energy storage subsystem 2 is a carbon dioxide phase change energy storage based system, and mainly includes a gas storage unit 21, an energy storage unit 22, a liquid storage unit 23 and an energy release unit 24 connected in sequence. The gas storage unit 21 is used to store gaseous carbon dioxide at normal pressure, and the liquid storage unit 23 is used to store liquid carbon dioxide. The gaseous carbon dioxide flowing out of the gas storage unit 21 is converted into liquid carbon dioxide at a preset energy storage pressure through the energy storage unit 22, flows into the liquid storage unit 23, and in this process, energy storage is completed. The liquid carbon dioxide output from the liquid storage unit 23 is converted into gaseous carbon dioxide at normal pressure through the energy release unit 24, flows into the gas storage unit 21, and in this process, energy release and application are completed. Generally, the gaseous carbon dioxide is compressed and liquefied into liquid carbon dioxide in the energy storage unit 22 during the low electricity consumption period or by using wind and light abandoned electricity, and stored in the liquid storage unit 23, and the energy conversion compression energy and heat energy are stored; during the electricity consumption peak period, the liquid carbon dioxide is gasified and expanded to do work by the energy release unit 24, and the stored energy is released and converted into electric energy for use.

[0044] The specific composition and structure of the gas storage unit 21, the energy storage unit 22, the liquid storage unit 23 and the energy release unit 24 can be realized by referring to the existing technology. The gas storage unit 21 is also called a gas storage warehouse, a gas storage library, a gas storage assembly, etc. in the prior art, and the liquid storage unit 23 is also called a liquid storage tank, a liquid storage container, an energy storage container, etc. in the prior art, for example, the technical solutions disclosed in the existing patent application files CN119289275A, CN116221616A, CN117628836A and CN116857027A.

[0045] As a specific case, in the embodiment, as shown in Figure 3As shown, the energy storage unit 22 mainly comprises a compressor 221, an energy storage heat exchanger 222 and a condenser 223 connected between the gas storage unit 21 and the liquid storage unit 23. The gaseous carbon dioxide in the gas storage unit 21 is compressed by the compressor 221, cooled by the energy storage heat exchanger 222 and liquefied by the condenser 223 to form liquid carbon dioxide stored in the liquid storage unit 23.

[0046] As a specific case, in the present embodiment, as shown in Figure 3 As shown, the energy storage unit 22 mainly comprises a compressor 221, an energy storage heat exchanger 222 and a condenser 223 connected between the gas storage unit 21 and the liquid storage unit 23. The gaseous carbon dioxide in the gas storage unit 21 is compressed by the compressor 221, cooled by the energy storage heat exchanger 222 and liquefied by the condenser 223 to form liquid carbon dioxide stored in the liquid storage unit 23.

[0047] As a specific case, in the present embodiment, as shown in Figure 1 and Figure 3 As shown, the energy storage unit 22 mainly comprises a compressor 221, an energy storage heat exchanger 222 and a condenser 223 connected between the gas storage unit 21 and the liquid storage unit 23. The gaseous carbon dioxide in the gas storage unit 21 is compressed by the compressor 221, cooled by the energy storage heat exchanger 222 and liquefied by the condenser 223 to form liquid carbon dioxide stored in the liquid storage unit 23.

[0048] In the present embodiment, the gas output pipeline 15 in the carbon capture subsystem 1 is coupled to the gas storage unit 21 of the energy storage subsystem 2, and the captured carbon dioxide gas (i.e. the carbon dioxide gas obtained by desorption in the desorption tower 14) is input to the gas storage unit 21 as the circulating working medium of the energy storage subsystem 2, and the energy storage unit 22 of the energy storage subsystem 2 is reused as the compression-condensation assembly of the carbon capture subsystem 1 to output liquid carbon dioxide for sequestration. Specifically, a carbon sequestration pipeline 231 can be connected from the liquid storage unit 23.

[0049] Thus, on the one hand, the low-pressure carbon dioxide gas produced by the carbon capture subsystem 1 can be directly stored in the gas storage unit 21. The gas storage unit 21 of the energy storage subsystem 2 is usually provided with a large-volume gas storage bin, which can store a large amount of low-pressure carbon dioxide gas, reduce the continuous production requirement of the downstream equipment in the traditional independent carbon capture system, and well balance the contradiction between continuous absorption and intermittent compression. The compression is performed during off-peak electricity, which significantly reduces the operation cost of the compressor and improves the carbon utilization efficiency and economic benefits. On the other hand, in the traditional independent carbon capture system, the carbon dioxide gas separated by carbon capture needs to be pressurized by a compressor, cooled and condensed by a heat exchanger, and then stored. In the traditional independent carbon dioxide energy storage system, the carbon dioxide gas also needs to be pressurized by a compressor, cooled and condensed by a heat exchanger during the energy storage stage. Both have significant commonalities. Therefore, the energy storage unit 22 of the energy storage subsystem is reused as the compression and condensation assembly of the carbon capture subsystem 1, and a set of energy storage process is adopted to complete energy storage while achieving carbon sequestration, thereby reducing the investment cost of the carbon capture subsystem.

[0050] Further, the gas output pipeline 15 is provided with a gas purification treatment unit 17, which is used for purifying the carbon dioxide gas output from the desorption tower 14 before being delivered to the gas storage unit 21.

[0051] In this embodiment, the lean liquid delivery pipeline 11 in the carbon capture subsystem 1 is coupled to the energy release unit 24 of the energy storage subsystem 2, so that the lean liquid with residual heat output from the desorption tower 14 is used as a heat source to evaporate and gasify the liquid carbon dioxide input into the energy release unit 24. Specifically, the lean liquid delivery pipeline 11 is coupled to the evaporator 241 in the energy release unit 24, so that the lean liquid with residual heat output from the desorption tower 14 is used as a heat source to provide heat to the evaporator 241, and evaporate and gasify the liquid carbon dioxide input into the evaporator 241 from the liquid storage unit 23.

[0052] In the traditional independent amine absorption method carbon capture system, the lean liquid output from the desorption tower 14 is still high in temperature (usually 60-70°C) after heat exchange in the lean-rich liquid heat exchanger 16, and needs to be cooled by introducing an external cold source (usually to below 40°C) before being transported to the absorption tower 13. In this embodiment, the lean liquid transport pipeline 11 is coupled to the energy release unit 24 of the energy storage subsystem 2, and the lean liquid with residual heat is used as the heat source for the evaporation and gasification of liquid carbon dioxide in the energy release stage, achieving the evaporation and gasification of liquid carbon dioxide while reducing the temperature of the lean liquid to improve the absorption efficiency of the lean liquid in the absorption tower 13. Thus, not only does the carbon capture subsystem 1 reduce its dependence on external energy (cold source), but also the energy storage subsystem 2 reduces its dependence on external energy (evaporation heat source), better achieving internal energy circulation, greatly improving the overall energy efficiency of the system, and reducing costs.

[0053] In this embodiment, the rich liquid transport pipeline 12 in the carbon capture subsystem 1 is coupled to the heat circulation unit 25 of the energy storage subsystem 2, and the high-temperature heat circulation medium in the heat circulation unit 25 is used as a heat source to heat and warm the rich liquid in the rich liquid transport pipeline 12.

[0054] In the amine method carbon capture process, amine adsorption liquid regeneration heating (heating the rich liquid before being transported to the desorption tower 14 to fully desorb carbon dioxide gas from the amine adsorption liquid) is the most energy-consuming link, and usually an external heat source is needed to heat the rich liquid before being transported to the desorption tower 14. In this embodiment, during the valley electricity period, the compressor is driven by low-cost electricity to compress the carbon dioxide gas into high-pressure liquid storage, and the heat generated during the compression process is absorbed and stored by the heat circulation unit 25, and the stored heat is used for the heating step of amine adsorption liquid regeneration, better achieving internal energy circulation, reducing the energy consumption of the carbon capture link, further optimizing energy utilization efficiency, and reducing costs.

[0055] In summary, the carbon dioxide energy storage system combined with carbon capture provided by the above embodiments takes industrial exhaust flue gas as a carbon dioxide supply source, uses amine solution absorption-desorption process to obtain high-purity gaseous carbon dioxide, and directly applies the gaseous carbon dioxide as an energy storage medium to a carbon dioxide compression phase change energy storage subsystem: when there is excess power, the excess power is used to drive a compressor in the energy storage subsystem to compress the carbon dioxide gas into liquid for storage, and the heat energy generated in the compression process is recovered to be used for desorption in a desorption tower, thereby replacing the traditional heating method for heating rich liquid and reducing energy consumption; during a peak period of the power grid, the stored high-pressure liquid carbon dioxide is evaporated and gasified to drive a turbine to generate power, the liquid carbon dioxide gasification process absorbs waste heat of lean liquid, the lean liquid is cooled to a suitable temperature, and then is supplemented into the absorption tower, thereby reducing the carbon capture cold energy demand, the generated power is used to supply the carbon capture subsystem to operate, and a closed cycle of 'capturing carbon-storing carbon-storing energy with carbon' is formed. Thus, the carbon capture subsystem based on the amine absorption method and the energy storage subsystem based on carbon dioxide phase change are deeply combined to construct a coordinated circulation system of material flow (carbon dioxide working medium) and energy flow (heat energy), the two systems are complementary to each other, and the dual benefits of improving energy utilization efficiency and reducing carbon capture process energy consumption are simultaneously achieved, thereby greatly reducing the production cost.

[0056] In specific solutions, as shown in Figure 1 and Figure 2 , the lean liquid conveying pipeline 11 includes a first lean liquid pipeline 111, a second lean liquid pipeline 112, and a third lean liquid pipeline 113.

[0057] The first lean liquid pipeline 111 is connected between the desorption tower 14 and the lean-rich liquid heat exchanger 16, the second lean liquid pipeline 112 is connected between the lean-rich liquid heat exchanger 16 and the energy release unit 24 (specifically connected to the evaporator 241), and the third lean liquid pipeline 113 is connected between the energy release unit 24 (specifically connected to the evaporator 241) and the absorption tower 13. Further, the first lean liquid pipeline 111 is provided with a lean liquid pump 115. The lean liquid obtained by desorption and regeneration in the desorption tower 14 is driven by the lean liquid pump 115 to be conveyed to the lean-rich liquid heat exchanger 16 through the first lean liquid pipeline 111 to exchange heat with the low-temperature rich liquid and reduce the temperature, and to increase the temperature of the rich liquid. The lean liquid with reduced temperature in the lean-rich liquid heat exchanger 16 is conveyed to the evaporator 241 in the energy release unit 24 through the second lean liquid pipeline 112 to exchange heat with the liquid carbon dioxide input into the evaporator 241 to further reduce the temperature and make the liquid carbon dioxide evaporate and gasify into carbon dioxide gas. The lean liquid with further reduced temperature in the evaporator 241 is conveyed to the absorption tower 13 through the third lean liquid pipeline 113 to absorb carbon dioxide in the industrial flue gas and form rich liquid.

[0058] As a preferred solution, in the embodiment, a fourth lean liquid pipeline 114 is connected between the second lean liquid pipeline 112 and the third lean liquid pipeline 113, and a cooler 116 is arranged on the fourth lean liquid pipeline 114, and the cooler 116 is configured to cool the lean liquid in the fourth lean liquid pipeline 114. In the non-energy releasing stage, since the energy releasing unit 24 stops running, the lean liquid cannot be further lowered in temperature by heat exchange with the liquid carbon dioxide in the evaporator 241, and at this time, the lean liquid lowered in temperature in the lean-rich liquid heat exchanger 16 is input to the fourth lean liquid pipeline 114 through the second lean liquid pipeline 112, and is further lowered in temperature by the cooler 116, and then is transported to the absorption tower 13 through the third lean liquid pipeline 113.

[0059] In a specific solution, as shown in Figure 1 and Figure 2 , the rich liquid conveying pipeline 12 includes a first rich liquid pipeline 121, a second rich liquid pipeline 122, a third rich liquid pipeline 123, and a rich liquid heat exchanger 124.

[0060] The first rich liquid pipeline 121 is connected between the absorption tower 13 and the lean-rich liquid heat exchanger 16, the second rich liquid pipeline 122 is connected between the lean-rich liquid heat exchanger 16 and the rich liquid heat exchanger 124, the third rich liquid pipeline 123 is connected between the rich liquid heat exchanger 124 and the desorption tower 14, and the rich liquid heat exchanger 124 is coupled to the heat circulation unit 25. Further, a rich liquid pump 125 is arranged on the first rich liquid pipeline 121. The rich liquid obtained in the absorption tower 13 is driven by the rich liquid pump 125 to be transported to the lean-rich liquid heat exchanger 16 through the first rich liquid pipeline 121 to exchange heat with the high-temperature lean liquid and increase the temperature, and to lower the temperature of the lean liquid. The rich liquid increased in temperature in the lean-rich liquid heat exchanger 16 is transported to the rich liquid heat exchanger 124 through the second rich liquid pipeline 122 to exchange heat with the high-temperature heat circulation medium input to the rich liquid heat exchanger 124 from the heat circulation unit 25 to further increase the temperature, and to lower the temperature of the high-temperature heat circulation medium. The rich liquid further increased in temperature in the rich liquid heat exchanger 124 is transported to the desorption tower 14 through the third rich liquid pipeline 123, and in the desorption tower 14, the rich liquid is desorbed to form lean liquid and carbon dioxide gas.

[0061] In the embodiment, as shown in Figure 1 and Figure 3 , the heat circulation unit 25 includes a heat storage container 251, a cold storage container 252, a first connecting pipeline 253, a second connecting pipeline 254, a third connecting pipeline 255, a fourth connecting pipeline 256, a fifth connecting pipeline 257, and a sixth connecting pipeline 258.

[0062] Specifically, the first connecting pipeline 253 is connected between the cold storage container 252 and the energy storage heat exchanger 222, the second connecting pipeline 254 is connected between the energy storage heat exchanger 222 and the heat storage container 251, the third connecting pipeline 255 is connected between the heat storage container 251 and the energy release heat exchanger 242, and the fourth connecting pipeline 256 is connected between the energy release heat exchanger 242 and the cold storage container 252. In the energy storage stage, the cold storage container 252 inputs the stored low-temperature heat cycle medium to the energy storage heat exchanger 222 through the first connecting pipeline 253 to absorb the compression heat and form high-temperature heat cycle medium, which is input to the heat storage container 251 through the second connecting pipeline 254 for storage. In the energy release stage, the heat storage container 251 inputs the stored high-temperature heat cycle medium to the energy release heat exchanger 242 through the third connecting pipeline 255 to release heat and heat the carbon dioxide gas in the energy release heat exchanger 242 to form low-temperature heat cycle medium, which is transported to the cold storage container 252 through the fourth connecting pipeline 256 for storage.

[0063] In the carbon dioxide phase change energy storage system, the heat energy generated in the compression process is collected and is usually used to heat the evaporated carbon dioxide gas in the energy release process. The heat source for energy release is usually only the compression heat in the energy storage process. When combined with carbon capture, a synergistic heat management mechanism can be formed. Since a large amount of compression heat is generated in the process of storing high-pressure carbon dioxide in the carbon capture process, the heat can be stored and used to heat the carbon dioxide gas in the energy release stage, providing high-quality heat for the energy release process, increasing the temperature of the carbon dioxide gas entering the expander, and thus improving the power generation efficiency.

[0064] The fifth connecting pipeline 257 is connected between the heat storage container 251 and the rich liquid heat exchanger 124, and the sixth connecting pipeline 258 is connected between the rich liquid heat exchanger 124 and the cold storage container 252. The heat storage container 251 inputs the stored high-temperature heat cycle medium to the rich liquid heat exchanger 124 through the fifth connecting pipeline 257 to release heat and heat the rich liquid in the rich liquid heat exchanger 124 to form low-temperature heat cycle medium, which is transported to the cold storage container 252 through the sixth connecting pipeline 258 for storage.

[0065] As a preferred solution, in the embodiment, the first connecting pipeline 253 is connected between the cold storage container 252 and the energy storage heat exchanger 222, the second connecting pipeline 254 is connected between the energy storage heat exchanger 222 and the heat storage container 251, the third connecting pipeline 255 is connected between the heat storage container 251 and the energy release heat exchanger 242, and the fourth connecting pipeline 256 is connected between the energy release heat exchanger 242 and the cold storage container 252. Figure 3As shown, the fourth connecting pipeline 256 is connected between the energy releasing heat exchanger 242 and the rich liquid heat exchanger 124. The low-temperature heat cycle medium (also having high residual heat) after heat exchange in the energy releasing heat exchanger 242 of the energy releasing unit 24 is first input to the rich liquid heat exchanger 124 for heat exchange with the rich liquid to further reduce the temperature, and then is delivered to the cold storage container 252 through the sixth connecting pipeline 258 for storage. Thus, in the energy releasing stage, the heat not fully utilized in the energy releasing unit 24 is used to heat the rich liquid, the heat demand is further finely matched, a heat cascade utilization network is constructed, the heat utilization efficiency is improved, the temperature of the rich liquid is increased, and the temperature of the heat cycle medium is further reduced, thereby not only reducing the dependence of the carbon capture subsystem on external energy (heat source), but also more favorably improving the heat storage efficiency of the heat cycle medium in the energy storage stage, greatly improving the overall energy efficiency of the system and reducing the cost.

[0066] Based on the carbon dioxide energy storage system combined with carbon capture provided in the above embodiment, the embodiment of the present application further provides a control method of the carbon dioxide energy storage system, and the control method comprises the following steps:

[0067] Step (one), control the absorption of carbon dioxide in the lean liquid in the absorption tower 13 in the industrial flue gas A1 to form a rich liquid, and deliver the rich liquid to the desorption tower 14 through the rich liquid delivery pipeline 12. In the process of delivering the rich liquid to the desorption tower 14 through the rich liquid delivery pipeline 12, the high-temperature heat cycle medium in the heat cycle unit 25 is used as a heat source to heat and warm the rich liquid in the rich liquid delivery pipeline 12 before being delivered to the desorption tower 14. Wherein, the flue gas A2 after purification by absorption is discharged from the top of the absorption tower 13.

[0068] Step (two), control the desorption of the rich liquid in the desorption tower 14 to obtain lean liquid and carbon dioxide gas, deliver the lean liquid to the absorption tower 13 through the lean liquid delivery pipeline 11, and deliver the carbon dioxide gas to the gas storage unit 21 through the gas output pipeline 15.

[0069] Step (three), in the energy storage stage, control the energy storage unit 22 to compress and liquefy the carbon dioxide gas in the gas storage unit 21 to form liquid carbon dioxide and deliver it to the liquid storage unit 23; wherein the low-temperature heat cycle medium in the heat cycle unit 25 absorbs and stores the heat generated by compressing the carbon dioxide gas in the energy storage unit 22. Wherein, the liquid carbon dioxide in the liquid storage unit 23 can be output to the outside for storage through the carbon storage pipeline 231.

[0070] Step (four), in the energy release stage, the energy release unit 24 is controlled to evaporate and gasify the liquid carbon dioxide in the liquid storage unit 23, and then heat and expand the liquid carbon dioxide to work externally, and form carbon dioxide gas to be delivered to the gas storage unit 21. The lean liquid with residual heat output from the desorption tower 14 is used as a heat source to evaporate and gasify the liquid carbon dioxide input into the energy release unit 24, and the high-temperature heat circulating medium in the heat circulation unit 25 is used as a heat source to heat and expand the evaporated and gasified carbon dioxide gas.

[0071] As a preferred scheme, in step (four), in the energy release stage, the heat circulating medium after heat exchange in the energy release unit 24 is controlled to exchange heat with the rich liquid in the rich liquid delivery pipeline 12, so that the heat circulating medium is further reduced in temperature before being delivered to the heat circulation unit 25.

[0072] In summary, the carbon dioxide energy storage system combined with carbon capture and the control method thereof provided by the above embodiments of the present application deeply combine the carbon capture subsystem based on the amine absorption method and the energy storage subsystem based on the phase change of carbon dioxide, construct a coordinated circulation system of material flow (carbon dioxide working medium) and energy flow (thermal energy), and complement each other, so that the dual benefits of improving energy utilization efficiency and reducing energy consumption in the carbon capture process are realized simultaneously, and the production cost is greatly reduced.

[0073] The above is only a specific embodiment of the present application, and it should be noted that, for those skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A carbon dioxide energy storage system in combination with carbon capture, characterized by, The system comprises: a carbon capture subsystem comprising an absorption tower and a desorption tower in circulation communication through a lean liquid delivery pipeline and a rich liquid delivery pipeline, and further comprising a gas output pipeline connected to the desorption tower; an energy storage subsystem comprising a gas storage unit, an energy storage unit, a liquid storage unit and an energy release unit connected in a closed loop, and further comprising a heat circulation unit connected between the energy storage unit and the energy release unit; wherein the gas output pipeline is coupled to the gas storage unit for delivering carbon dioxide gas captured by the carbon capture subsystem to the gas storage unit as a circulating working medium of the energy storage subsystem, and the energy storage unit is reused as a compression-condensation assembly of the carbon capture subsystem to output liquid carbon dioxide for sequestration; wherein the lean liquid delivery pipeline is coupled to the energy release unit to evaporate and gasify liquid carbon dioxide input into the energy release unit by using the lean liquid output from the desorption tower as a heat source; wherein the carbon capture subsystem further comprises a lean-rich liquid heat exchanger, the lean liquid delivery pipeline comprises a first lean liquid pipeline, a second lean liquid pipeline and a third lean liquid pipeline, the rich liquid delivery pipeline comprises a first rich liquid pipeline, a second rich liquid pipeline, a third rich liquid pipeline and a rich liquid heat exchanger, the energy storage unit is provided with an energy storage heat exchanger, the energy release unit is provided with an energy release heat exchanger, and the heat circulation unit comprises a heat storage container, a cold storage container, a first connecting pipeline, a second connecting pipeline, a third connecting pipeline, a fourth connecting pipeline, a fifth connecting pipeline and a sixth connecting pipeline; wherein the first connecting pipeline is connected between the cold storage container and the energy storage heat exchanger, the second connecting pipeline is connected between the energy storage heat exchanger and the heat storage container, the third connecting pipeline is connected between the heat storage container and the energy release heat exchanger, the fourth connecting pipeline is connected between the energy release heat exchanger and the rich liquid heat exchanger, the fifth connecting pipeline is connected between the heat storage container and the rich liquid heat exchanger, and the sixth connecting pipeline is connected between the rich liquid heat exchanger and the cold storage container; the heat circulation medium after heat exchange in the energy release unit is delivered to the cold storage container in sequence via the rich liquid heat exchanger and the sixth connecting pipeline.

2. The carbon capture integrated carbon dioxide storage energy system of claim 1, wherein, The first lean liquid pipeline is connected between the desorption tower and the lean-rich liquid heat exchanger, the second lean liquid pipeline is connected between the lean-rich liquid heat exchanger and the energy release unit, and the third lean liquid pipeline is connected between the energy release unit and the absorption tower; the first rich liquid pipeline is connected between the absorption tower and the lean-rich liquid heat exchanger, the second rich liquid pipeline is connected between the lean-rich liquid heat exchanger and the rich liquid heat exchanger, and the third rich liquid pipeline is connected between the rich liquid heat exchanger and the desorption tower.

3. The carbon capture integrated carbon dioxide storage energy system of claim 2, wherein, The energy release unit is provided with an evaporator, the second lean liquid pipeline is connected between the lean-rich liquid heat exchanger and the evaporator, and the third lean liquid pipeline is connected between the evaporator and the absorption tower.

4. The carbon capture integrated carbon dioxide storage energy system of claim 3, wherein, A fourth lean liquid pipeline is connected between the second lean liquid pipeline and the third lean liquid pipeline, and a cooler is arranged on the fourth lean liquid pipeline, which is used to cool the lean liquid in the second lean liquid pipeline and then deliver the cooled lean liquid to the absorption tower through the third lean liquid pipeline.

5. The carbon capture integrated carbon dioxide storage energy system of claim 4, wherein, A lean liquid pump is arranged on the first lean liquid pipeline, and a rich liquid pump is arranged on the first rich liquid pipeline.

6. The carbon capture integrated carbon dioxide storage energy system of claim 5, wherein, A gas purification treatment unit is arranged on the gas output pipeline, which is used to purify the carbon dioxide gas output from the desorption tower and then deliver the purified carbon dioxide gas to the gas storage unit.

7. A control method of a carbon dioxide storage energy system in combination with carbon capture as claimed in claim 6, characterized by, Comprise: Control the lean liquid in the absorption tower to absorb the carbon dioxide in the industrial flue gas to form rich liquid, and deliver the rich liquid to the desorption tower through the rich liquid delivery pipeline; Control the desorption tower to desorb the rich liquid to obtain lean liquid and carbon dioxide gas, deliver the lean liquid to the absorption tower through the lean liquid delivery pipeline, and deliver the carbon dioxide gas to the gas storage unit through the gas output pipeline; In the energy storage stage, control the energy storage unit to compress and liquefy the carbon dioxide gas in the gas storage unit to form liquid carbon dioxide and deliver it to the liquid storage unit; wherein the low-temperature heat circulating medium in the heat circulation unit absorbs and stores the heat generated by the energy storage unit compressing the carbon dioxide gas; In the energy release stage, control the energy release unit to evaporate and gasify the liquid carbon dioxide in the liquid storage unit and then do work after heating and expansion to form carbon dioxide gas and deliver it to the gas storage unit; wherein the lean liquid with residual heat output from the desorption tower is used as a heat source to evaporate and gasify the liquid carbon dioxide input into the energy release unit; the high-temperature heat circulating medium in the heat circulation unit is used as a heat source to heat and expand the evaporated and gasified carbon dioxide gas; Wherein, the high-temperature heat circulating medium in the heat circulation unit is used as a heat source to heat and warm the rich liquid in the rich liquid delivery pipeline and then deliver it to the desorption tower.

8. The control method according to claim 7, characterized by, In the energy release stage, control the heat circulating medium after heat exchange in the energy release unit to exchange heat with the rich liquid in the rich liquid delivery pipeline, so that the heat circulating medium is further reduced in temperature and then delivered to the heat circulation unit. In the energy release stage, control the heat circulating medium after heat exchange in the energy release unit to exchange heat with the rich liquid in the rich liquid delivery pipeline, so that the heat circulating medium is further reduced in temperature and then delivered to the heat circulation unit.

Images