A peak-shifting energy utilization carbon capture system based on absorbent storage

Abstract

The present application provides a peak-shifting energy utilization carbon capture system based on absorbent storage, belonging to the technical field of energy environment. The system includes a rich / lean liquid heat exchanger, a lean liquid module, a carbon absorption module, and a rich liquid module connected in sequence. The inlet of the lean liquid module is connected to the outlet of the hot fluid channel of the rich / lean liquid heat exchanger, and the outlet of the rich liquid module is connected to the inlet of the cold fluid channel of the rich / lean liquid heat exchanger. The system also includes a regeneration module and a reboiler connected to each other. The outlet of the cold fluid channel of the rich / lean liquid heat exchanger is connected to the regeneration module, and the reboiler is connected to the inlet of the hot fluid channel of the rich / lean liquid heat exchanger. Through the processing solution of the present application, the high-energy-consuming regeneration process is concentrated in the valley electricity period for operation, realizing power plant peak shaving while improving the economy of the overall operation of the carbon capture and thermal power generation systems.

Description

Technical Field

[0001] This application relates to the technical field of energy and environment, and particularly relates to a peak-shifting energy utilization carbon capture system based on absorbent storage. Background Art

[0002] To address the carbon emission problem brought about by the energy supply mode mainly based on fossil energy consumption, in addition to continuously increasing the utilization ratio of renewable energy represented by solar energy and wind energy, carbon emission reduction during the utilization process of traditional fossil energy is also a core measure in the coming long period. Carbon capture can directly separate CO2 from the fossil energy utilization process, and through carbon sequestration, compress the separated CO2 to a supercritical high-pressure state and transport it to geological environments such as underground saline aquifers, and use geological conditions such as high pressure and sealing to permanently sequester CO2, thereby directly and effectively achieving carbon emission reduction.

[0003] Currently, the carbon capture technical routes include pre-combustion capture, oxy-fuel combustion, and post-combustion capture. Among them, the post-combustion capture technology process is relatively mature and has better adaptability to existing energy utilization systems, and can generally be directly applied to any existing thermal power generation system. Post-combustion capture methods include chemical absorption, physical adsorption / absorption, membrane separation, cryogenic separation, etc. Among them, the chemical absorption method has the most mature process, but its popularization and application are insufficient due to high regeneration energy consumption. The energy consumption of the chemical absorption method is mainly concentrated in the regeneration process of the rich liquid absorbed with CO2 to release CO2 in the regeneration tower and reform into lean liquid. The heating heat source is generally steam directly extracted from the power plant, with too high energy consumption, resulting in a significant decline in the power generation efficiency of the power plant. Summary of the Invention

[0004] In view of this, the embodiments of this application provide a peak-shifting energy utilization carbon capture system based on absorbent storage, which at least partially solves the problem that the heating heat source in the lean liquid regeneration process in the prior art is generally steam directly extracted from the power plant, with too high energy consumption.

[0005] The embodiments of this application provide a peak-shifting energy utilization carbon capture system based on absorbent storage. The system includes a rich-lean liquid heat exchanger, a lean liquid module, a carbon absorption module, and a rich liquid module connected in sequence. The inlet of the lean liquid module is connected to the outlet of the hot fluid channel of the rich-lean liquid heat exchanger, and the outlet of the rich liquid module is connected to the inlet of the cold fluid channel of the rich-lean liquid heat exchanger; the system further includes a connected regeneration module and a reboiler. The outlet of the cold fluid channel of the rich-lean liquid heat exchanger is connected to the regeneration module, and the reboiler is connected to the inlet of the hot fluid channel of the rich-lean liquid heat exchanger;

[0006] The carbon absorption module is used to make the lean absorbent liquid flowing out of the lean liquid module absorb the carbon-containing tail gas from the outside and form a rich absorbent liquid. The rich absorbent liquid successively passes through the rich liquid module, the cold fluid channel of the rich and lean liquid heat exchanger, and the regeneration module to generate the regenerated lean absorbent liquid. The regenerated lean absorbent liquid flows into the reboiler and is heated by external heat source steam to form gas-phase steam and liquid-phase lean absorbent liquid. The gas-phase steam enters the regeneration module as the regeneration heat source, and the liquid-phase lean absorbent liquid flows out to the hot fluid channel of the rich and lean liquid heat exchanger for countercurrent heat and mass transfer with the rich absorbent liquid in the cold fluid channel of the rich and lean liquid heat exchanger. The cooled liquid-phase lean absorbent liquid is stored in the lean liquid module.

[0007] According to a specific implementation manner of an embodiment of the present application, the regeneration module includes a regeneration tower. The first inlet of the regeneration tower is connected to the outlet of the cold fluid channel of the rich and lean liquid heat exchanger. The first outlet of the regeneration tower is connected to the inlet of the reboiler. The second inlet of the regeneration tower is connected to the first outlet of the reboiler. The second outlet of the reboiler is connected to the inlet of the hot fluid channel of the rich and lean liquid heat exchanger. The second outlet of the regeneration tower is successively connected to a regenerated gas condenser, a gas-liquid separator, and the third inlet of the regeneration tower. The gas-liquid separator is also provided with a gas discharge port.

[0008] The regeneration tower is used to perform countercurrent heat and mass transfer between the rich absorbent liquid flowing into the regeneration tower and the steam discharged from the first outlet of the reboiler to the regeneration tower. The rich absorbent liquid releases the absorbed gas to form a regenerated gas and a regenerated lean absorbent liquid. The regenerated gas is cooled by the regenerated gas condenser and separated into gas and liquid by the gas-liquid separator. The generated gas is discharged from the gas discharge port, and the remaining liquid phase flows back through the third inlet of the regeneration tower. The regenerated lean absorbent liquid flows from the first outlet of the regeneration tower to the reboiler and is heated by external heat source steam to form gas-phase steam and liquid-phase lean absorbent liquid. The gas-phase steam enters through the second inlet of the regeneration tower to provide the regeneration heat source, and the liquid-phase lean absorbent liquid flows out through the second outlet of the reboiler to the inlet of the hot fluid channel of the rich and lean liquid heat exchanger.

[0009] According to a specific implementation manner of an embodiment of the present application, a reflux pump is provided between the gas-liquid separator and the third inlet of the regeneration tower. The remaining liquid phase in the gas-liquid separator is driven by the reflux pump to flow back to the regeneration tower.

[0010] According to a specific implementation manner of an embodiment of the present application, a first lean liquid pump is provided between the reboiler and the inlet of the hot fluid channel of the rich and lean liquid heat exchanger. The liquid-phase lean absorbent liquid formed in the reboiler is driven by the first lean liquid pump to flow to the hot fluid channel of the rich and lean liquid heat exchanger.

[0011] According to a specific implementation manner of an embodiment of the present application, the carbon absorption module includes an off-gas pretreatment device and an absorption tower. A first inlet of the absorption tower is connected to the off-gas pretreatment device, a second inlet of the absorption tower is connected to the lean liquid module, a first outlet of the absorption tower is connected to the rich liquid module, and a second outlet of the absorption tower is used for discharging decarbonized gas; the carbon-containing off-gas enters the absorption tower after being treated by the off-gas pretreatment device and is absorbed by the lean liquid of the absorption liquid flowing from the lean liquid module to the absorption tower, generating the rich liquid of the absorption liquid and the decarbonized gas.

[0012] According to a specific implementation manner of an embodiment of the present application, the lean liquid module includes a second lean liquid pump, a lean liquid storage tank, and a lean liquid cooler connected in sequence. An inlet of the lean liquid cooler is connected to an outlet of a hot fluid channel of the rich-lean liquid heat exchanger, and an outlet of the second lean liquid pump is connected to an inlet of the carbon absorption module.

[0013] According to a specific implementation manner of an embodiment of the present application, the rich liquid module includes a rich liquid storage tank and a rich liquid pump connected to each other. An inlet of the rich liquid storage tank is connected to an outlet of the carbon absorption module, and an outlet of the rich liquid pump is connected to an inlet of a cold fluid channel of the rich-lean liquid heat exchanger.

[0014] Beneficial effects

[0015] In the peak-shaving energy utilization carbon capture system based on absorption liquid storage in the embodiment of the present application, the rich liquid formed after the lean liquid absorbs CO2 in the carbon capture system is stored in a storage tank. During the low electricity consumption period, the rich liquid in the rich liquid storage tank enters the regeneration tower and is regenerated by heating with steam provided by the power plant to release CO2, and the formed lean liquid is stored in the lean liquid storage tank, thereby realizing the decoupling of the absorption and regeneration processes of the absorption liquid for CO2, and concentrating the regeneration process during the valley electricity period.

[0016] The present application separates the absorption of CO2 by the absorption liquid and the regeneration process through the storage of the lean liquid and rich liquid of the absorption liquid, and concentrates the high-energy-consuming regeneration process during the valley electricity period. While realizing the peak shaving of the power plant, it improves the economic efficiency of the overall operation of the carbon capture and thermal power generation systems, and effectively promotes the industrialization and popularization of carbon capture technology. Description of the drawings

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0018] Figure 1Schematic diagram of a peak-shifting energy utilization carbon capture system based on absorbent storage according to an embodiment of the present invention;

[0019] Figure 2 Circulation path of the lean absorbent absorbing carbon dioxide link according to an embodiment of the present invention;

[0020] Figure 3 Circulation path of the rich absorbent regeneration link according to an embodiment of the present invention.

[0021] In the figure: 1, tail gas pretreatment device; 2, absorption tower; 3, rich liquid storage tank; 4, rich liquid pump; 5, lean-rich liquid heat exchanger; 6, regeneration tower; 7, reboiler; 8, first lean liquid pump; 9, lean liquid cooler; 10, lean liquid storage tank; 11, second lean liquid pump; 12, regenerated gas condenser; 13, gas-liquid separator; 14, reflux pump. Specific implementation manners

[0022] The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0023] The following uses specific specific examples to illustrate the implementation manners of the present application. Those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts belong to the scope of protection of the present application.

[0024] It should be noted that the following describes various aspects of the embodiments within the scope of the appended claims. It should be obvious that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is illustrative only. Based on the present application, those skilled in the art should understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement the device and / or practice the method. In addition, this device and / or this method can be implemented using other structures and / or functionality in addition to one or more of the aspects described herein.

[0025] It should also be noted that the diagrams provided in the following embodiments only illustrate the basic concept of the present application in a schematic manner. The diagrams only show the components related to the present application, rather than being drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and ratio of each component in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0026] In addition, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the described aspects can be practiced without these specific details.

[0027] Currently, the main research and development directions of the chemical absorption method are to develop new absorbents and optimize the process flow to improve the absorption / regeneration efficiency of the absorbent and reduce the energy consumption of carbon capture. However, the progress is relatively slow, and there is still a certain distance from actual popularization and application. The direct result of high energy consumption is high carbon capture operation cost and poor system investment economy. From the perspective of economy, the concept of off-peak operation can be introduced. The main energy consumption link of absorbent regeneration is set to operate during the low electricity consumption period. At the same time, steam is extracted from the steam power generation system during the low electricity consumption period to reduce the external work output of the steam turbine, which can play a role in peak regulation, and then improve the overall economic benefits of the carbon capture and thermal power generation systems. The specific implementation method is as follows: The rich liquid formed after the lean liquid in the carbon capture system absorbs CO2 is stored in a storage tank. During the low electricity consumption period, the rich liquid in the rich liquid storage tank enters the regeneration tower and is regenerated by the steam provided by the power plant to release CO2. The formed lean liquid is stored in the lean liquid storage tank, thereby realizing the decoupling of the absorption and regeneration processes of the absorbent for CO2, and concentrating the regeneration process during the low electricity consumption period.

[0028] The embodiment of the present application provides a carbon capture system for off-peak energy utilization based on absorbent storage, which will be described in detail below with reference to the drawings.

[0029] Refer to Figure 1 , the carbon capture system for off-peak energy utilization based on absorbent storage includes a rich-lean liquid heat exchanger 5 and a lean liquid module, a carbon absorption module, and a rich liquid module connected in sequence. The inlet of the lean liquid module is connected to the outlet of the hot fluid channel of the rich-lean liquid heat exchanger 5, and the outlet of the rich liquid module is connected to the inlet of the cold fluid channel of the rich-lean liquid heat exchanger 5; the system also includes a connected regeneration module and a reboiler 7. The outlet of the cold fluid channel of the rich-lean liquid heat exchanger 5 is connected to the regeneration module, and the reboiler 7 is connected to the inlet of the hot fluid channel of the rich-lean liquid heat exchanger 5.

[0030] The lean liquid module is used to store the lean absorbent liquid. The carbon absorption module is used to enable the lean absorbent liquid flowing out of the lean liquid module to absorb the external carbon-containing tail gas and form a rich absorbent liquid. The formed rich absorbent liquid is stored in the rich liquid module. When the lean absorbent liquid is regenerated, the rich absorbent liquid sequentially passes through the rich liquid module, the cold fluid channel of the lean-rich liquid heat exchanger 5 and the regeneration module to generate the regenerated lean absorbent liquid. The regenerated lean absorbent liquid flows into the reboiler 7 and is heated by the external heat source steam to form gas-phase steam and liquid-phase lean absorbent liquid. The gas-phase steam enters the regeneration module as the regeneration heat source, and the liquid-phase lean absorbent liquid flows out to the hot fluid channel of the lean-rich liquid heat exchanger 5 to perform countercurrent heat and mass transfer with the rich absorbent liquid in the cold fluid channel of the lean-rich liquid heat exchanger 5. The cooled liquid-phase lean absorbent liquid is stored in the lean liquid module. Among them, the reboiler 7 is also provided with a steam inlet and a steam outlet. The external heat source steam enters from the steam inlet of the reboiler 7 and performs countercurrent heat and mass transfer with the regenerated lean absorbent liquid, and then the external heat source steam that has lost heat flows out from the steam outlet of the reboiler 7.

[0031] In the above embodiment, the rich absorbent liquid formed after the lean absorbent liquid in the carbon capture system absorbs CO2 is stored in the rich liquid module. During the low electricity consumption period, the rich absorbent liquid in the rich liquid module enters the regeneration module and is regenerated by heating with the steam provided by the power plant to release CO2. The formed lean absorbent liquid is stored in the lean liquid module, thereby realizing the decoupling of the absorption and regeneration processes of the absorbent liquid for CO2, and concentrating the regeneration process during the valley electricity period. While realizing the peak shaving of the power plant, the overall operation economy of the carbon capture and thermal power generation system is improved, effectively promoting the industrialization and popularization of carbon capture technology.

[0032] In a specific embodiment, the regeneration module includes a regeneration tower 6. The top of the regeneration tower 6 is provided with a first inlet, a third inlet, and a second outlet. The bottom of the regeneration tower 6 is provided with a first outlet and a second inlet. The first inlet of the regeneration tower 6 is connected to the outlet of the cold fluid channel of the rich and lean liquid heat exchanger 5. The first outlet of the regeneration tower 6 is connected to the inlet of the reboiler 7. The second inlet of the regeneration tower 6 is connected to the first outlet of the reboiler 7. The second outlet of the reboiler 7 is connected to the inlet of the hot fluid channel of the rich and lean liquid heat exchanger 5. The second outlet of the regeneration tower 6 is sequentially connected to a regeneration gas condenser 12, a gas-liquid separator 13, and the third inlet of the regeneration tower 6 to form a complete loop. The top of the gas-liquid separator 13 is provided with a gas discharge outlet. In this embodiment, the regeneration tower 6 is used to perform countercurrent heat and mass transfer between the absorbent rich liquid flowing into the regeneration tower 6 and the steam discharged from the first outlet of the reboiler 7 to the regeneration tower 6. The absorbed gas is released from the absorbent rich liquid to form regeneration gas and the regenerated absorbent lean liquid. The regeneration gas is cooled by the regeneration gas condenser 12 and separated into gas and liquid by the gas-liquid separator 13. The generated gas is discharged from the gas discharge outlet and flows to the subsequent treatment link. The remaining liquid phase flows back through the third inlet of the regeneration tower 6. The regenerated absorbent lean liquid flows from the first outlet of the regeneration tower 6 to the reboiler 7, is heated by external heat source steam to form gas-phase steam and liquid-phase absorbent lean liquid. The gas-phase steam enters through the second inlet of the regeneration tower 6 to provide a regeneration heat source. The liquid-phase absorbent lean liquid flows out from the second outlet of the reboiler 7 to the inlet of the hot fluid channel of the rich and lean liquid heat exchanger 5.

[0033] It should be noted that the regeneration gas entering the regeneration gas condenser 12 is a mixture of CO2 and water vapor, etc. After being condensed by the regeneration gas condenser 12, it forms gaseous CO2 (which may contain a small amount of water vapor) and liquid water (which may dissolve a small amount of CO2), and then enters the gas-liquid separator 13. Therefore, the gas flowing out from the top of the gas-liquid separator 13 is mainly gaseous CO2, and the bottom is not liquid CO2, but water dissolved with a small amount of CO2, that is, the so-called liquid phase. The liquid phase part returns to the regeneration tower 6 again.

[0034] In a specific embodiment, a reflux pump 14 is provided between the gas-liquid separator 13 and the third inlet of the regeneration tower 6. The remaining liquid phase in the gas-liquid separator 13 is driven by the reflux pump 14 to flow back to the regeneration tower 6.

[0035] In a specific embodiment, a first lean liquid pump 8 is provided between the reboiler 7 and the inlet of the hot fluid channel of the rich and lean liquid heat exchanger 5. The liquid-phase absorbent lean liquid formed in the reboiler 7 is driven by the first lean liquid pump 8 to flow to the hot fluid channel of the rich and lean liquid heat exchanger 5. The liquid-phase absorbent lean liquid entering the hot fluid channel of the rich and lean liquid heat exchanger 5 preheats the rich liquid in the cold fluid channel and is cooled at the same time.

[0036] In a specific embodiment, the carbon absorption module includes an exhaust gas pretreatment device 1 and an absorption tower 2. The exhaust gas pretreatment device 1 is used to pretreat the carbon-containing exhaust gas discharged externally. The absorption tower 2 has a first inlet, a second inlet, a first outlet and a second outlet. The first inlet of the absorption tower 2 is connected to the exhaust gas pretreatment device 1, the second inlet of the absorption tower 2 is connected to the lean liquid module, the first outlet of the absorption tower 2 is connected to the rich liquid module, and the second outlet of the absorption tower 2 is an exhaust outlet. The decarbonized gas formed after absorption treatment is exhausted through the second outlet of the absorption tower 2; the carbon-containing exhaust gas enters the absorption tower 2 after being treated by the exhaust gas pretreatment device 1 and is absorbed by the lean liquid of the absorption liquid flowing from the lean liquid module to the absorption tower 2, generating rich liquid of the absorption liquid and decarbonized gas.

[0037] In a specific embodiment, the lean liquid module includes a second lean liquid pump 11, a lean liquid storage tank 10 and a lean liquid cooler 9 connected in sequence. The inlet of the lean liquid cooler 9 is connected to the outlet of the hot fluid channel of the rich-lean liquid heat exchanger 5, and the outlet of the second lean liquid pump 11 is connected to the inlet of the carbon absorption module. Specifically, the second outlet of the reboiler 7, the inlet and outlet of the first lean liquid pump 8, the inlet and outlet of the hot fluid channel of the rich-lean liquid heat exchanger 5, the inlet and outlet of the lean liquid cooler 9, and the inlet of the lean liquid storage tank 10 are connected in sequence to form a lean liquid regenerative cooling and storage channel.

[0038] In a specific embodiment, the rich liquid module includes a connected rich liquid storage tank 3 and a rich liquid pump 4. The inlet of the rich liquid storage tank 3 is connected to the outlet of the carbon absorption module, and the outlet of the rich liquid pump 4 is connected to the inlet of the cold fluid channel of the rich-lean liquid heat exchanger 5.

[0039] The peak-shaving energy utilization carbon capture system based on absorption liquid storage of the present application is divided into three working modes, namely, a single absorption working mode, a single regeneration working mode and a full-state working mode. During peak electricity consumption or non-low electricity consumption periods, only the link of absorbing CO2 with lean liquid of the absorption liquid is carried out, that is, the single absorption working mode, and at the same time, the rich liquid formed by absorbing CO2 is stored in the rich liquid storage tank 3; during low electricity consumption periods, the steam led out from the power plant is used to regenerate the absorption liquid, and the lean liquid obtained by regeneration enters the lean liquid storage tank 10 for storage. At the same time, since the carbon-containing exhaust gas is continuously discharged, the absorption of CO2 by the lean liquid is carried out synchronously at this time, that is, the full-state working mode; if there is no carbon-containing exhaust gas discharged during low electricity consumption periods, only the absorption liquid regeneration link is operated, that is, the single regeneration working mode. The above working modes are described separately as follows:

[0040] 1) Single absorption working mode

[0041] In the single absorption operation mode, a large amount of lean absorbent obtained through regeneration has been stored in the lean liquid storage tank 10. The discharged carbon-containing tail gas is processed by the tail gas pretreatment device 1 and then enters the first inlet at the bottom of the absorption tower 2. At the same time, the lean liquid stored in the lean liquid storage tank 10 is drawn out by the second lean liquid pump 11 and enters the second inlet at the top of the absorption tower 2. The two perform countercurrent heat and mass transfer in the absorption tower. Finally, CO2 in the carbon-containing tail gas is absorbed by the lean liquid, and the decarbonized gas is directly discharged from the second outlet at the top of the absorption tower 2. The lean liquid absorbs CO2 to form rich liquid, which enters the rich liquid storage tank for storage. The flow paths of each medium in the single absorption operation mode are as Figure 2 shown.

[0042] 2) Single regeneration operation mode

[0043] In this mode, a large amount of rich liquid formed by absorbing CO2 has been stored in the rich liquid storage tank 3. At this time, the rich liquid is in a cold state and is drawn out by the rich liquid pump 4 and enters the cold fluid channel of the rich-lean liquid heat exchanger 5, where it exchanges heat with the hot lean liquid driven by the first lean liquid pump 8 and entering the hot fluid channel of the rich-lean liquid heat exchanger 5. The cold rich liquid is heated to a hot state and then enters the first inlet at the upper part of the regeneration tower 6. At the same time, the steam discharged from the first outlet of the reboiler 7 (obtained by heating with external steam) enters the second inlet at the bottom of the regeneration tower 6. The hot rich liquid and the steam perform countercurrent heat and mass transfer in the regeneration tower 6.

[0044] Carbon dioxide is released from the rich liquid to form the regeneration gas, which is discharged from the second outlet at the top of the regeneration tower 6, enters the regeneration gas condenser 12 for cooling, and then enters the gas-liquid separator 13 for gas-liquid separation. The gaseous CO2 is discharged from the second outlet at the top of the gas-liquid separator 13 and enters the subsequent treatment process. The liquid phase part is driven by the reflux pump 14 and refluxes through the third inlet of the regeneration tower 6.

[0045] The absorbent liquid at the bottom of the regeneration tower 6 flows out from the first outlet of the regeneration tower 6, enters the inside of the reboiler 7 through the reboiler 7 inlet, is heated by the external heat source steam, and the formed gaseous steam enters the regeneration tower 6 through the second inlet of the regeneration tower 6 to provide the regeneration heat source. The liquid phase lean liquid at the bottom of the reboiler 7 flows out through the second outlet of the reboiler 7, is driven by the first lean liquid pump 8, and enters the hot fluid channel of the rich-lean liquid heat exchanger 5 to preheat the rich liquid in the cold fluid channel, while being cooled itself. The cooled lean liquid is further cooled by the lean liquid cooler 9 and then enters the lean liquid storage tank 10 for storage.

[0046] The flow paths of each medium in the single regeneration operation mode are as Figure 3 shown.

[0047] 3) Full state operation mode

[0048] In this mode, the absorption and regeneration processes occur simultaneously. However, the working flow rates of the lean / rich solution corresponding to the two processes do not necessarily have to be the same. Due to the flow rate difference, the accumulated lean / rich absorption liquid is stored in the lean / rich solution storage tank, and the insufficient lean / rich solution is obtained from the lean / rich solution storage tank.

[0049] The circulation paths of each medium in the full-state working mode are as Figure 1 shown.

[0050] This application introduces the concept of off-peak operation, setting the main energy-consuming link of absorption liquid regeneration to operate during the low electricity consumption period. At the same time, steam is extracted from the steam power generation system during the valley electricity period to reduce the external work output of the steam turbine, which can play a role in peak shaving, thereby realizing the improvement of the overall economic benefits of the carbon capture and thermal power generation systems. The specific implementation method is as follows: The rich liquid formed after the lean liquid in the carbon capture system absorbs CO2 is stored in the storage tank. During the low electricity consumption period, the rich liquid in the rich liquid storage tank enters the regeneration tower and is regenerated by the steam provided by the power plant to release CO2. The formed lean liquid is stored in the lean liquid storage tank, thereby realizing the decoupling of the absorption and regeneration processes of the absorption liquid for CO2, and concentrating the regeneration process during the valley electricity period.

[0051] Therefore, this patent separates the processes of absorption liquid absorbing CO2 and regeneration by storing the lean and rich solutions of the absorption liquid, and concentrates the high-energy-consuming regeneration process during the valley electricity period. While realizing peak shaving for the power plant, it improves the overall operation economy of the carbon capture and thermal power generation systems, effectively promoting the industrialization and popularization of carbon capture technology.

[0052] The above is only the specific implementation mode of this application, but the protection scope of this application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in this application should be covered within the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claims.

Claims

1. A peak-shifting energy utilization carbon capture system based on absorbent storage, characterized in that, The system includes a lean-rich liquid heat exchanger (5), a lean liquid module, a carbon absorption module, and a rich liquid module connected in sequence. The inlet of the lean liquid module is connected to the outlet of the hot fluid channel of the lean-rich liquid heat exchanger (5), and the outlet of the rich liquid module is connected to the inlet of the cold fluid channel of the lean-rich liquid heat exchanger (5). The system also includes a regeneration module and a reboiler (7) connected to each other. The outlet of the cold fluid channel of the lean-rich liquid heat exchanger (5) is connected to the regeneration module, and the reboiler (7) is connected to the inlet of the hot fluid channel of the lean-rich liquid heat exchanger (5). The carbon absorption module is used to make the lean absorption liquid flowing out of the lean liquid module absorb the external carbon-containing tail gas to form a rich absorption liquid. The rich absorption liquid sequentially passes through the rich liquid module, the cold fluid channel of the lean-rich liquid heat exchanger (5), and the regeneration module to generate a regenerated lean absorption liquid. The regenerated lean absorption liquid flows into the reboiler (7) and is heated by external heat source steam to form a gas-phase steam and a liquid-phase lean absorption liquid. The gas-phase steam enters the regeneration module as a regeneration heat source, and the liquid-phase lean absorption liquid flows out to the hot fluid channel of the lean-rich liquid heat exchanger (5) to perform countercurrent heat and mass transfer with the rich absorption liquid in the cold fluid channel of the lean-rich liquid heat exchanger (5). The cooled liquid-phase lean absorption liquid is stored in the lean liquid module. The regeneration module includes a regeneration tower (6). The first inlet of the regeneration tower (6) is connected to the outlet of the cold fluid channel of the lean-rich liquid heat exchanger (5). The first outlet of the regeneration tower (6) is connected to the inlet of the reboiler (7). The second inlet of the regeneration tower (6) is connected to the first outlet of the reboiler (7). The second outlet of the reboiler (7) is connected to the inlet of the hot fluid channel of the lean-rich liquid heat exchanger (5). The second outlet of the regeneration tower (6) is sequentially connected to a regenerated gas condenser, a gas-liquid separator (13), and the third inlet of the regeneration tower (6). The gas-liquid separator (13) is also provided with a gas discharge port. The regeneration tower (6) is used to perform countercurrent heat and mass transfer between the rich absorption liquid flowing into the regeneration tower (6) and the steam discharged from the first outlet of the reboiler (7) to the regeneration tower (6). The rich absorption liquid releases the absorbed gas to form a regenerated gas and a regenerated lean absorption liquid. The regenerated gas is cooled by the regenerated gas condenser and undergoes gas-liquid separation by the gas-liquid separator (13). The generated gas is discharged from the gas discharge port, and the remaining liquid phase flows back through the third inlet of the regeneration tower (6). The regenerated lean absorption liquid flows from the first outlet of the regeneration tower (6) to the reboiler (7), is heated by external heat source steam to form a gas-phase steam and a liquid-phase lean absorption liquid. The gas-phase steam enters through the second inlet of the regeneration tower (6) to provide a regeneration heat source, and the liquid-phase lean absorption liquid flows out through the second outlet of the reboiler (7) to the inlet of the hot fluid channel of the lean-rich liquid heat exchanger (5).

2. The peak-shifting energy utilization carbon capture system based on absorbent storage according to claim 1, wherein, A reflux pump (14) is provided between the gas-liquid separator (13) and the third inlet of the regeneration tower (6), and the remaining liquid phase in the gas-liquid separator (13) is driven by the reflux pump (14) to flow back to the regeneration tower (6).

3. The peak-shifting energy utilization carbon capture system based on absorbent storage according to claim 1, wherein A first lean liquid pump (8) is provided between the reboiler (7) and the inlet of the hot fluid channel of the lean-rich liquid heat exchanger (5), and the lean liquid of the liquid phase absorption liquid formed in the reboiler (7) is driven by the first lean liquid pump (8) to flow into the hot fluid channel of the lean-rich liquid heat exchanger (5).

4. The peak-shifting energy utilization carbon capture system based on absorbent storage according to claim 1, characterized in that, The carbon absorption module includes a tail gas pretreatment device (1) and an absorption tower (2). The first inlet of the absorption tower (2) is connected to the tail gas pretreatment device (1), the second inlet of the absorption tower (2) is connected to the lean liquid module, the first outlet of the absorption tower (2) is connected to the rich liquid module, and the second outlet of the absorption tower (2) is used for discharging decarbonized gas; the carbon-containing tail gas is processed by the tail gas pretreatment device (1) and then enters the absorption tower (2) and is absorbed by the lean liquid of the absorption liquid flowing from the lean liquid module to the absorption tower (2), generating the rich liquid of the absorption liquid and the decarbonized gas.

5. The peak-shifting energy utilization carbon capture system based on absorbent storage according to any one of claims 1-4, characterized in that The lean liquid module includes a second lean liquid pump (11), a lean liquid storage tank (10) and a lean liquid cooler (9) connected in sequence. The inlet of the lean liquid cooler (9) is connected to the outlet of the hot fluid channel of the lean-rich liquid heat exchanger (5), and the outlet of the second lean liquid pump (11) is connected to the inlet of the carbon absorption module.

6. The peak-shifting energy utilization carbon capture system based on absorbent storage according to any one of claims 1-4, characterized in that, The rich liquid module includes a rich liquid storage tank (3) and a rich liquid pump (4) connected to each other. The inlet of the rich liquid storage tank (3) is connected to the outlet of the carbon absorption module, and the outlet of the rich liquid pump (4) is connected to the inlet of the cold fluid channel of the lean-rich liquid heat exchanger (5).

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