Carbon dioxide trapping system and heat pump type waste heat recycling module thereof

Abstract

The utility model provides a heat pump type waste heat recycling module for a carbon dioxide capturing system and the carbon dioxide capturing system comprising the heat pump type waste heat recycling module. According to the heat pump type waste heat recycling module, waste heat of regenerated gas and compressed regenerated gas is recycled through the waste heat recycling heat pump, and the recycled waste heat is directly or indirectly reused for carbon dioxide desorption through the waste heat utilization device, so that efficient utilization of the waste heat of the regenerated gas and the compressed regenerated gas is achieved; therefore, the heat energy consumption of the carbon dioxide capture system is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of carbon dioxide capture, in particular to a heat pump type waste heat regeneration module for a carbon dioxide capture system and a carbon dioxide capture system comprising the heat pump type waste heat regeneration module. Background Art

[0002] Carbon dioxide capture is an important technical choice for deep emission reduction in fossil energy industries such as thermal power, steel, cement, and chemical industry. Carbon dioxide capture technology based on chemical absorption is considered to be one of the most promising technical routes for large-scale carbon dioxide capture due to its mature process, high capture efficiency, and good flue gas adaptability. The process flow of traditional chemical absorption carbon dioxide capture is as follows: the carbon-containing flue gas emitted by thermal power plants, smelters, cement plants, chemical plants, etc. enters the bottom of the absorption tower after cooling, and contacts the absorbent sprayed from the top of the tower in reverse in the tower. During the gas-liquid contact process, the absorbent reacts chemically with the carbon dioxide in the flue gas to produce products such as carbamate, carbonate, and bicarbonate. The rich liquid after absorbing carbon dioxide is sent to the lean-rich liquid heat exchanger for heat exchange. The heated carbon dioxide rich liquid enters the desorption tower for carbon dioxide desorption and absorbent regeneration. At the bottom of the desorption tower, the carbon dioxide rich liquid exchanges heat with the steam in the reboiler. The absorbent is heated to a certain temperature for carbon dioxide desorption. The desorbed carbon dioxide is discharged from the top of the tower and compressed to a certain pressure after condensation and gas-liquid separation for subsequent transportation and storage. The lean liquid after desorption of carbon dioxide undergoes heat exchange in the lean-rich liquid heat exchanger, and then is cooled by the lean liquid cooler before entering the top of the absorption tower for the second cycle of carbon dioxide capture.

[0003] However, the traditional chemical CO2 capture has technical bottlenecks such as high energy consumption and high operating costs due to insufficient utilization of waste heat and poor cold / heat energy synergy matching, which hinders the commercialization of this technology. In particular, for high-grade regeneration gas waste heat and compressed regeneration gas waste heat, the utilization efficiency is low and the waste heat is not fully utilized, which leads to high energy consumption in the CO2 desorption process. Utility Model Content

[0004] In view of the above problems, the present invention proposes a carbon dioxide capture system and a heat pump type waste heat regeneration module thereof, which overcome the above problems or at least partially solve the above problems.

[0005] One purpose of the utility model is to fully utilize the waste heat of regenerated gas and compressed regenerated gas.

[0006] Another object of the present invention is to achieve full quality improvement of the recovered regeneration gas and the waste heat of the compressed regeneration gas, thereby improving the energy efficiency of the system.

[0007] In particular, according to one aspect of the utility model, a heat pump type waste heat regeneration module for a carbon dioxide capture system is provided, comprising: a desorption tower having a regeneration gas outlet, a gas-liquid separator connected to the regeneration gas outlet of the desorption tower through a pipeline, and a regeneration gas compression device connected to the gas outlet of the gas-liquid separator; wherein the heat pump type waste heat regeneration module further comprises:

[0008] The fourth heat pump waste heat recovery and utilization component includes:

[0009] a fourth waste heat recovery heat pump, comprising a sixth waste heat recovery heat exchanger arranged in a pipeline between the regeneration gas outlet of the desorption tower and the gas-liquid separator and a seventh waste heat recovery heat exchanger connected to the regeneration gas compression device, the sixth waste heat recovery heat exchanger being configured to allow the heat pump working fluid flowing therethrough to perform heat exchange with the regeneration gas output from the regeneration gas outlet in the sixth waste heat recovery heat exchanger to recover the waste heat of the regeneration gas, and the seventh waste heat recovery heat exchanger being configured to allow the heat pump working fluid flowing therethrough to perform heat exchange with the compressed regeneration gas generated by the regeneration gas compression device in the seventh waste heat recovery heat exchanger to recover the waste heat of the compressed regeneration gas; and

[0010] The fourth waste heat utilization device is correspondingly connected to the working fluid loop of the fourth waste heat recovery heat pump and is connected to the bottom of the desorption tower. It is configured to utilize the recovered regeneration gas waste heat and the compressed regeneration gas waste heat to heat the lean liquid at the bottom of the desorption tower through heat exchange to desorb carbon dioxide.

[0011] Optionally, the heat pump working fluid flowing through the sixth waste heat recovery heat exchanger and the seventh waste heat recovery heat exchanger is the same sixth heat pump working fluid;

[0012] The fourth waste heat recovery heat pump is a single-stage compression heat pump, which includes a seventh waste heat recovery heat exchanger, a sixth waste heat recovery heat exchanger, a sixth working medium compressor and a sixth throttle valve which are sequentially connected through pipelines to form a sixth working medium loop for circulating the sixth heat pump working medium, and the fourth waste heat utilization device is connected in the pipeline between the sixth working medium compressor and the sixth throttle valve;

[0013] The sixth working medium loop is configured to allow the sixth heat pump working medium flowing out of the sixth throttle valve to flow into the seventh waste heat recovery heat exchanger and the sixth waste heat recovery heat exchanger in liquid state in sequence to exchange heat with the compressed regeneration gas and the regeneration gas respectively and then undergo phase change to be converted into steam, and after being compressed by the sixth working medium compressor, enter the sixth waste heat utilization device to heat the lean liquid at the bottom of the desorption tower, and then pass through the sixth throttle valve for throttling and cooling to be converted into liquid state, thereby completing the working medium cycle.

[0014] Optionally, the heat pump working fluid flowing through the sixth waste heat recovery heat exchanger and the seventh waste heat recovery heat exchanger is the same sixth heat pump working fluid;

[0015] The fourth waste heat recovery heat pump is a single-stage compression heat pump, comprising a seventh waste heat recovery heat exchanger, a sixth waste heat recovery heat exchanger, a sixth working fluid compressor and a sixth throttle valve, wherein the seventh waste heat recovery heat exchanger and the sixth waste heat recovery heat exchanger are connected in parallel and then sequentially connected to the sixth working fluid compressor and the sixth throttle valve through a pipeline to form a sixth working fluid loop for circulating the working fluid of the sixth heat pump, and the fourth waste heat utilization device is connected in the pipeline between the sixth working fluid compressor and the sixth throttle valve;

[0016] The sixth working fluid loop is configured to allow the sixth heat pump working fluid flowing out of the sixth throttle valve to be diverted in liquid form into the seventh waste heat recovery heat exchanger and the sixth waste heat recovery heat exchanger to undergo phase change and be converted into steam after heat exchange with the compressed regeneration gas and the regeneration gas respectively, and then enter the sixth waste heat utilization device to heat the lean liquid at the bottom of the desorption tower after being compressed by the sixth working fluid compressor, and then pass through the sixth throttle valve for throttling and cooling to be converted into liquid, thereby completing the working fluid cycle.

[0017] Optionally, the fourth waste heat recovery heat pump includes a mutually independent regeneration gas waste heat recovery heat pump unit and a compressed regeneration gas waste heat recovery heat pump unit, wherein the regeneration gas waste heat recovery heat pump unit includes a sixth waste heat recovery heat exchanger to recover the waste heat of the regeneration gas, and the compressed regeneration gas waste heat recovery heat pump unit includes a seventh waste heat recovery heat exchanger to recover the waste heat of the compressed regeneration gas;

[0018] The fourth waste heat utilization device includes a mutually independent regeneration gas waste heat utilization device and a compressed regeneration gas waste heat utilization device, wherein the regeneration gas waste heat utilization device is connected to the working fluid loop of the regeneration gas waste heat recovery heat pump unit and is connected to the bottom of the desorption tower, and is configured to utilize the recovered regeneration gas waste heat to heat the middle-lean liquid at the bottom of the desorption tower through heat exchange to desorb carbon dioxide; the compressed regeneration gas waste heat utilization device is connected to the working fluid loop of the compressed regeneration gas waste heat recovery heat pump unit and is connected to the bottom of the desorption tower, and is configured to utilize the recovered compressed regeneration gas waste heat to heat the middle-lean liquid at the bottom of the desorption tower through heat exchange to desorb carbon dioxide.

[0019] Optionally, the regeneration gas waste heat recovery heat pump unit is a single-stage compression heat pump, comprising a sixth waste heat recovery heat exchanger, a seventh working fluid compressor and a seventh throttle valve which are sequentially connected through pipelines to form a seventh working fluid loop for circulating the seventh heat pump working fluid, and the regeneration gas waste heat utilization device is connected in the pipeline between the seventh working fluid compressor and the seventh throttle valve;

[0020] The seventh working fluid loop is configured so that the seventh heat pump working fluid flows into the sixth waste heat recovery heat exchanger in liquid form, undergoes a phase change and is converted into steam after heat exchange with the regeneration gas, is compressed by the seventh working fluid compressor, enters the regeneration gas waste heat utilization device to heat the lean liquid at the bottom of the desorption tower, and then passes through the seventh throttle valve for throttling and cooling to be converted into liquid form, and then flows into the sixth waste heat recovery heat exchanger.

[0021] Optionally, the compressed regeneration gas waste heat recovery heat pump unit is a single-stage compression heat pump, comprising a seventh waste heat recovery heat exchanger, an eighth working fluid compressor and an eighth throttle valve which are sequentially connected through pipelines to form an eighth working fluid loop for circulating the eighth heat pump working fluid, and the compressed regeneration gas waste heat utilization device is connected in the pipeline between the eighth working fluid compressor and the eighth throttle valve;

[0022] The eighth working fluid loop is configured to allow the eighth heat pump working fluid to flow into the seventh waste heat recovery heat exchanger in a liquid state, undergo a phase change and be converted into steam after heat exchange with the compressed regeneration gas, be compressed by the eighth working fluid compressor and enter the compressed regeneration gas waste heat utilization device to heat the lean liquid at the bottom of the desorption tower, then pass through the eighth throttle valve for throttling and cooling to be converted into a liquid state, and then flow into the seventh waste heat recovery heat exchanger.

[0023] Optionally, the regeneration gas compression device includes a multi-stage sub-compressor, and the multi-stage sub-compressors are sequentially connected in series to form a step-by-step compression structure;

[0024] The seventh waste heat recovery heat exchanger includes a plurality of interstage heat exchangers in parallel, and the plurality of interstage heat exchangers and the multi-stage sub-compressors are arranged at intervals along the flow direction of the compressed regeneration gas, wherein each interstage heat exchanger except the last interstage heat exchanger arranged along the flow direction of the compressed regeneration gas is arranged between the outlet of the previous stage sub-compressor and the inlet of the next stage sub-compressor, and the compressed gas inlet of the last interstage heat exchanger is connected to the compressed gas outlet of the last stage sub-compressor.

[0025] Optionally, the regeneration gas compression device includes a multi-stage sub-compressor, and the multi-stage sub-compressors are sequentially connected in series to form a step-by-step compression structure;

[0026] The seventh waste heat recovery heat exchanger includes a plurality of interstage heat exchangers connected in series, and the plurality of interstage heat exchangers and the multi-stage sub-compressors are arranged at intervals along the flow direction of the compressed regeneration gas, wherein each interstage heat exchanger except the last interstage heat exchanger arranged along the flow direction of the compressed regeneration gas is arranged between the outlet of the previous stage sub-compressor and the inlet of the next stage sub-compressor, and the compressed gas inlet of the last interstage heat exchanger is connected to the compressed gas outlet of the last stage sub-compressor.

[0027] Optionally, each waste heat utilization device includes a first reboiler, which is configured to perform heat exchange between the medium-lean liquid drawn from the bottom of the desorption tower and the working fluid after absorbing heat in the corresponding waste heat recovery heat pump to desorb carbon dioxide, and then return to the bottom of the desorption tower, and make the working fluid after heat exchange at least partially undergo phase change to liquid working fluid, and output the working fluid after heat exchange; or

[0028] Each waste heat utilization device includes a second reboiler connected to the bottom of the desorption tower, a condensing heat exchanger connected to the working fluid loop of the corresponding waste heat recovery heat pump, and a flash evaporator connected between the second reboiler and the condensing heat exchanger, wherein the condensing heat exchanger is configured to perform heat exchange between water entering the condensing heat exchanger and the working fluid after absorbing heat in the corresponding waste heat recovery heat pump to produce a high-temperature fluid, and to at least partially condense the working fluid after the heat exchange into a liquid working fluid, and output the working fluid after the heat exchange; the flash evaporator is configured to flash the high-temperature fluid from the condensing heat exchanger to produce water vapor and liquid water, and output the water vapor and liquid water to the second reboiler and the condensing heat exchanger respectively; the second reboiler is configured to perform heat exchange between the lean liquid drawn from the bottom of the desorption tower and the water vapor from the flash evaporator to desorb carbon dioxide, and then return to the bottom of the desorption tower, and at the same time, the water vapor is condensed into condensed water and then output to the condensing heat exchanger.

[0029] According to another aspect of the utility model, a carbon dioxide capture system is also provided, comprising: an absorption tower and a lean-rich liquid heat exchanger; wherein the carbon dioxide capture system also comprises any of the aforementioned heat pump type waste heat regeneration modules, wherein the cold rich liquid inlet, hot rich liquid outlet, hot lean liquid inlet and cold lean liquid outlet of the lean-rich liquid heat exchanger are respectively connected to the rich liquid outlet of the absorption tower, the first rich liquid feed inlet of the desorption tower, the hot lean liquid outlet of the desorption tower and the lean liquid feed inlet of the absorption tower through pipelines.

[0030] In the heat pump type waste heat regeneration and utilization module and the carbon dioxide capture system provided by the utility model, the waste heat of the regenerated gas and the compressed regenerated gas is recovered by a waste heat recovery heat pump, and the recovered waste heat is reused for carbon dioxide desorption by a waste heat utilization device, so as to realize full utilization of the waste heat of the regenerated gas and the compressed regenerated gas.

[0031] Furthermore, in the heat pump type waste heat regeneration module and carbon dioxide capture system provided by the utility model, a single-stage compression heat pump is used to fully improve the waste heat of the recovered regeneration gas and the compressed regeneration gas, which has a higher COP efficiency, thereby improving the energy efficiency of the system.

[0032] The above description is only an overview of the technical solution of the utility model. In order to more clearly understand the technical means of the utility model, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are listed below.

[0033] Based on the detailed description of the specific embodiments of the present invention in combination with the accompanying drawings below, those skilled in the art will become more aware of the above and other purposes, advantages and features of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solution of the utility model, some embodiments of the utility model will be described below with reference to the accompanying drawings. Those skilled in the art should understand that the same figure number indicates the same or similar parts or components in different drawings; the drawings of the utility model are not necessarily drawn to scale. In the drawings:

[0035] Figure 1 It is a schematic structural block diagram of a heat pump type waste heat regeneration module according to an embodiment of the utility model;

[0036] Figure 2 It is a schematic structural block diagram of a heat pump type waste heat regeneration module according to another embodiment of the utility model;

[0037] Figure 3 This is a structural schematic diagram of a heat pump type waste heat regeneration module according to an embodiment of the utility model;

[0038] Figure 4 It is a structural schematic diagram of a heat pump type waste heat regeneration module according to another embodiment of the utility model;

[0039] Figure 5 It is a structural schematic diagram of a heat pump type waste heat regeneration module according to another embodiment of the utility model;

[0040] Figure 6 is a schematic structural block diagram of a carbon dioxide capture system according to an embodiment of the utility model;

[0041] Figure 7 is a schematic structural block diagram of a carbon dioxide capture system according to another embodiment of the utility model;

[0042] Figure 8 is a schematic structural block diagram of a carbon dioxide capture system according to another embodiment of the utility model;

[0043] Fig. 9 It is a structural schematic diagram of a carbon dioxide capture system according to an embodiment of the utility model;

[0044] Fig.10 It is a structural schematic diagram of a carbon dioxide capture system according to an embodiment of the utility model;

[0045] Fig.11 It is a partial structural schematic diagram of a carbon dioxide capture system according to an embodiment of the utility model;

[0046] Fig.12 A schematic diagram of a third or fourth waste heat recovery heat exchanger using multi-stage parallel sub-heat exchangers according to an embodiment of the utility model;

[0047] Fig.13A schematic diagram of a third or fourth waste heat recovery heat exchanger using multi-stage series sub-heat exchangers according to an embodiment of the utility model;

[0048] Fig.14 It is a structural schematic diagram of a carbon dioxide capture system according to an embodiment of the utility model;

[0049] Fig.15 is a schematic structural block diagram of a carbon dioxide capture system according to an embodiment of the utility model;

[0050] Fig.16 It is a structural schematic diagram of a carbon dioxide capture system according to an embodiment of the utility model;

[0051] Fig.17 It is a structural schematic diagram of a carbon dioxide capture system according to an embodiment of the utility model;

[0052] Fig.18 It is a structural schematic diagram of a carbon dioxide capture system according to an embodiment of the utility model;

[0053] Fig.19 It is a partial structural schematic diagram of a carbon dioxide capture system according to an embodiment of the utility model;

[0054] Fig. 20 It is a structural schematic diagram of a carbon dioxide capture system according to an embodiment of the utility model;

[0055] Fig.21 It is a schematic diagram of a regeneration gas compression device using multi-stage compression and a corresponding waste heat recovery heat exchanger using multi-stage parallel inter-stage heat exchangers according to an embodiment of the utility model;

[0056] Fig. 22 It is a schematic diagram of a regeneration gas compression device using multi-stage compression and a corresponding waste heat recovery heat exchanger using multi-stage series inter-stage heat exchangers according to an embodiment of the utility model;

[0057] Fig.23 It is a schematic diagram of the structure of each waste heat utilization device according to an embodiment of the utility model;

[0058] Fig.24 It is a structural schematic diagram of each waste heat utilization device according to another embodiment of the utility model;

[0059] Fig.25 This is a comparison diagram of the change in CO2 reaction heat before and after introducing metal ions into an organic amine absorbent according to an embodiment of the utility model. DETAILED DESCRIPTION

[0060] It should be understood by those skilled in the art that the embodiments described below are only a part of the embodiments of the present invention, rather than all the embodiments of the present invention, and the embodiments are intended to explain the technical principles of the present invention, rather than to limit the protection scope of the present invention. Based on the embodiments provided by the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should still fall within the protection scope of the present invention.

[0061] Moreover, one or more examples of embodiments of the utility model are shown in the accompanying drawings. Each example is provided by way of explanation of the utility model and is not a limitation of the utility model. In fact, it is obvious to those skilled in the art that various modifications and variations can be made to the utility model without departing from the scope or spirit of the utility model. For example, a feature shown or described as part of one embodiment can be used together with another embodiment to produce yet another embodiment.

[0062] It should be noted that in the description of the present invention, the terms "center", "upper", "lower", "top", "bottom", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings, which are only for the convenience of description, and do not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", "third" and the like are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0063] Furthermore, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate component, or it can be a communication between the two elements. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0064] In addition, it should be noted that, for the purpose of keeping the images clear, some connecting lines are omitted in the multiple drawings of the present application, and the same letters are used to indicate that two points are actually connected, that is, two points represented by the same letters are actually connected. Figure 2 In the figure, point R at the regeneration gas waste heat utilization device 560 is actually connected to point R at the bottom of the desorption tower 130.

[0065] The embodiment of the present utility model provides a heat pump type waste heat regeneration module 600 for a carbon dioxide capture system 10 .

[0066] Figure 1 It is a schematic structural block diagram of a heat pump type waste heat regeneration module 600 according to an embodiment of the utility model.

[0067] See also Figure 1 As shown, the heat pump type waste heat regeneration and utilization module 600 may include a desorption tower 130 having a regeneration gas outlet 133, a gas-liquid separator 191 connected to the regeneration gas outlet 133 of the desorption tower 130 through a pipeline, a regeneration gas compression device 140 connected to the gas outlet of the gas-liquid separator 191, and a fourth heat pump type waste heat recovery and utilization component 45.

[0068] The gas-liquid separator 191 is connected between the regeneration gas outlet 133 and the regeneration gas compression device 140. The liquid outlet of the gas-liquid separator 191 is connected to the liquid return port at the top of the desorption tower 130. The carbon dioxide regeneration gas flowing out of the regeneration gas outlet 133 enters the gas-liquid separator 191 for gas-liquid separation. The separated liquid returns to the desorption tower 130 from the liquid return port.

[0069] The fourth heat pump type waste heat recovery and utilization component 45 may include a fourth waste heat recovery heat pump 450 and a fourth waste heat utilization device 460 .

[0070] The fourth waste heat recovery heat pump 460 includes a sixth waste heat recovery heat exchanger 451 disposed in a pipeline between the regeneration gas outlet 133 of the desorption tower 130 and the gas-liquid separator 191, and a seventh waste heat recovery heat exchanger 452 connected to the regeneration gas compression device 140. The sixth waste heat recovery heat exchanger 451 is configured to allow the heat pump working fluid flowing therethrough to exchange heat with the regeneration gas output from the regeneration gas outlet 133 in the sixth waste heat recovery heat exchanger 451 to recover the waste heat of the regeneration gas. The seventh waste heat recovery heat exchanger 452 is configured to allow the heat pump working fluid flowing therethrough to exchange heat with the compressed regeneration gas generated by the regeneration gas compression device 140 in the seventh waste heat recovery heat exchanger 452 to recover the waste heat of the compressed regeneration gas.

[0071] The fourth waste heat utilization device 460 is correspondingly connected to the working fluid loop of the fourth waste heat recovery heat pump 450 and is connected to the bottom of the desorption tower 130. It is configured to utilize the recovered regeneration gas waste heat and the compressed regeneration gas waste heat to heat the lean liquid at the bottom of the desorption tower 130 through heat exchange to desorb carbon dioxide.

[0072] The heat pump type waste heat regeneration and utilization module 600 provided in the embodiment of the utility model recovers the waste heat of the regenerated gas and the compressed regenerated gas through a waste heat recovery heat pump, and reuses the recovered waste heat for carbon dioxide desorption through a waste heat utilization device, so as to fully utilize the waste heat of the regenerated gas and the compressed regenerated gas.

[0073] Figure 2It is a schematic structural block diagram of a heat pump waste heat regeneration module 600 according to another embodiment of the utility model.

[0074] See also Figure 2 As shown, in some optional embodiments, the fourth waste heat recovery heat pump 450 includes a mutually independent regeneration gas waste heat recovery heat pump unit 550 and a compressed regeneration gas waste heat recovery heat pump unit 650, wherein the regeneration gas waste heat recovery heat pump unit 550 includes a sixth waste heat recovery heat exchanger 451 to recover the waste heat of the regeneration gas, and the compressed regeneration gas waste heat recovery heat pump unit 650 includes a seventh waste heat recovery heat exchanger 452 to recover the waste heat of the compressed regeneration gas.

[0075] The fourth waste heat utilization device 460 includes a regeneration gas waste heat utilization device 560 and a compressed regeneration gas waste heat utilization device 660 which are independent of each other. The regeneration gas waste heat utilization device 560 is connected to the working fluid loop of the regeneration gas waste heat recovery heat pump unit 550 and is connected to the bottom of the desorption tower 130, and is configured to utilize the recovered regeneration gas waste heat to heat the middle lean liquid at the bottom of the desorption tower 130 through heat exchange to desorb carbon dioxide. The compressed regeneration gas waste heat utilization device 660 is connected to the working fluid loop of the compressed regeneration gas waste heat recovery heat pump unit 650 and is connected to the bottom of the desorption tower 130, and is configured to utilize the recovered compressed regeneration gas waste heat to heat the middle lean liquid at the bottom of the desorption tower 130 through heat exchange to desorb carbon dioxide.

[0076] In some further embodiments, see Figure 3 As shown, the regeneration gas waste heat recovery heat pump unit 550 is a single-stage compression heat pump, including a sixth waste heat recovery heat exchanger 451, a seventh working medium compressor 552 and a seventh throttle valve 553, which are sequentially connected through pipelines to form a seventh working medium loop 554 for circulating the seventh heat pump working medium. The regeneration gas waste heat utilization device 560 is connected in the pipeline between the seventh working medium compressor 552 and the seventh throttle valve 553.

[0077] The seventh working fluid loop 554 is configured to allow the seventh heat pump working fluid to flow into the sixth waste heat recovery heat exchanger 451 in liquid form, undergo a phase change and be converted into steam after exchanging heat with the regenerated gas, and then enter the regenerated gas waste heat utilization device 560 after being compressed by the seventh working fluid compressor 552 to heat the lean liquid at the bottom of the desorption tower 130, and then pass through the seventh throttle valve 553 for throttling and cooling to be converted into liquid form, and then flow into the sixth waste heat recovery heat exchanger 451.

[0078] Continue to see Figure 3In some further embodiments, the compressed regeneration gas waste heat recovery heat pump unit 650 is a single-stage compression heat pump, including a seventh waste heat recovery heat exchanger 452, an eighth working medium compressor 652 and an eighth throttle valve 653, which are sequentially connected through pipelines to form an eighth working medium loop 654 for circulating the eighth heat pump working medium. The compressed regeneration gas waste heat utilization device 660 is connected in the pipeline between the eighth working medium compressor 652 and the eighth throttle valve 653.

[0079] The eighth working fluid loop 654 is configured to allow the eighth heat pump working fluid to flow into the seventh waste heat recovery heat exchanger 452 in a liquid state, undergo a phase change and be converted into steam after heat exchange with the compressed regeneration gas, and then enter the compressed regeneration gas waste heat utilization device 660 after being compressed by the eighth working fluid compressor 652 to heat the lean liquid at the bottom of the desorption tower 130, and then pass through the eighth throttle valve 653 for throttling and cooling to be converted into a liquid state, and then flow into the seventh waste heat recovery heat exchanger 452.

[0080] Figure 4 FIG. 6 is a schematic structural diagram of a heat pump waste heat regeneration module 600 according to another embodiment of the present invention.

[0081] See also Figure 4 As shown, in some optional embodiments, the heat pump working fluid flowing through the sixth waste heat recovery heat exchanger 451 and the seventh waste heat recovery heat exchanger 452 is the same sixth heat pump working fluid. The fourth waste heat recovery heat pump 450 is a single-stage compression heat pump, which includes a seventh waste heat recovery heat exchanger 452, a sixth waste heat recovery heat exchanger 451, a sixth working fluid compressor 453 and a sixth throttle valve 454, which are sequentially connected through pipelines to form a sixth working fluid loop 455 for the circulation of the sixth heat pump working fluid. The fourth waste heat utilization device 460 is connected in the pipeline between the sixth working fluid compressor 453 and the sixth throttle valve 454.

[0082] The sixth working fluid loop 455 is configured to allow the sixth heat pump working fluid flowing out of the sixth throttle valve 454 to flow into the seventh waste heat recovery heat exchanger 452 and the sixth waste heat recovery heat exchanger 451 in liquid state in sequence to undergo phase change and be converted into steam after heat exchange with the compressed regeneration gas and the regeneration gas respectively, and then enter the sixth waste heat utilization device 460 after being compressed by the sixth working fluid compressor 453 to heat the lean liquid at the bottom of the desorption tower 130, and then pass through the sixth throttle valve 454 for throttling and cooling to be converted into liquid state, thereby completing the working fluid cycle.

[0083] Figure 5 Schematic diagram of the structure of a heat pump waste heat regeneration module 600 according to another embodiment of the utility model.

[0084] See also Figure 5As shown, in some optional embodiments, the heat pump working fluid flowing through the sixth waste heat recovery heat exchanger 451 and the seventh waste heat recovery heat exchanger 452 is the same sixth heat pump working fluid. The fourth waste heat recovery heat pump 450 is a single-stage compression heat pump, including the seventh waste heat recovery heat exchanger 452, the sixth waste heat recovery heat exchanger 451, the sixth working fluid compressor 453 and the sixth throttle valve 454. The seventh waste heat recovery heat exchanger 452 and the sixth waste heat recovery heat exchanger 451 are connected in parallel and then sequentially connected to the sixth working fluid compressor 453 and the sixth throttle valve 454 through a pipeline to form a sixth working fluid loop 455 for the circulation of the sixth heat pump working fluid. The fourth waste heat utilization device 460 is connected in the pipeline between the sixth working fluid compressor 453 and the sixth throttle valve 454.

[0085] The sixth working fluid loop 455 is configured to allow the sixth heat pump working fluid flowing out of the sixth throttle valve 454 to be diverted in liquid form into the seventh waste heat recovery heat exchanger 452 and the sixth waste heat recovery heat exchanger 451 to undergo phase change and be converted into steam after heat exchange with the compressed regeneration gas and the regeneration gas respectively. After merging, the working fluid is compressed by the sixth working fluid compressor 453 and then enters the sixth waste heat utilization device 460 to heat the lean liquid at the bottom of the desorption tower 130. Thereafter, the working fluid is throttled and cooled by the sixth throttle valve 454 to be converted into liquid, thereby completing the working fluid cycle.

[0086] The heat pump waste heat regeneration module 600 provided in the embodiment of the utility model utilizes a single-stage compression heat pump to fully improve the waste heat of the recovered regeneration gas and the compressed regeneration gas, and has a higher COP efficiency, thereby improving the energy efficiency of the system.

[0087] In some optional embodiments, the regeneration gas compression device 140 may adopt multi-stage compression. Accordingly, the seventh waste heat recovery heat exchanger 452 may include a plurality of inter-stage heat exchangers 851. These inter-stage heat exchangers 851 may be connected in parallel or in series to recover the waste heat of each stage of compressed gas.

[0088] Fig.21 Schematic diagram of a regeneration gas compression device 140 using multi-stage compression and a seventh waste heat recovery heat exchanger 452 using multi-stage parallel inter-stage heat exchangers 851 according to an embodiment of the present invention. Fig.21 As shown, the regeneration gas compression device 140 includes a multi-stage sub-compressor 140', and the multi-stage sub-compressors 140' are sequentially connected in series to form a step-by-step compression structure. That is, the carbon dioxide regeneration gas adopts a multi-stage compression process.

[0089] When multiple interstage heat exchangers 851 are connected in parallel, the multiple interstage heat exchangers 851 and the multi-stage sub-compressor 140' are arranged at intervals along the flow direction of the regenerated gas. Each interstage heat exchanger 851 except the last interstage heat exchanger 851 arranged along the flow direction of the compressed regenerated gas is arranged between the outlet of the previous sub-compressor 140' and the inlet of the next sub-compressor 140'. The compressed gas inlet of the last interstage heat exchanger 851 is connected to the compressed gas outlet of the last sub-compressor 140', and the compressed gas outlet can be connected to other subsequent carbon dioxide processing sections for subsequent storage and transportation. The working fluid inlet 851a of each interstage heat exchanger 851 can be connected to the source component of the cryogenic liquid working fluid (for example, the corresponding throttle valve) through a pipeline. The working fluid outlet 851b of each inter-stage heat exchanger 851 can be connected to the corresponding working fluid compressor respectively, or it can be first connected to a confluence node (such as a confluence pipe, not shown in the figure), and the confluence node is further connected to the corresponding working fluid compressor. The working fluid steam output from the working fluid outlet 851b of all inter-stage heat exchangers 851 is collected through the confluence node and then transported to the corresponding working fluid compressor.

[0090] Fig. 22 Schematic diagram of a regeneration gas compression device 140 using multi-stage compression and a seventh waste heat recovery heat exchanger 452 using multi-stage series inter-stage heat exchangers 851 according to an embodiment of the present invention. Fig. 22 As shown, the regeneration gas compression device 140 includes a multi-stage sub-compressor 140', and the multi-stage sub-compressors 140' are sequentially connected in series to form a stage-by-stage compression structure.

[0091] In the case where multiple interstage heat exchangers 851 are connected in series, the multiple interstage heat exchangers 851 and the multi-stage sub-compressors 140' are arranged at intervals along the flow direction of the regenerated gas. Each interstage heat exchanger 851 except the last interstage heat exchanger 851 arranged along the flow direction of the compressed regenerated gas is arranged between the outlet of the previous sub-compressor 140' and the inlet of the next sub-compressor 140'. The compressed gas inlet of the last interstage heat exchanger 851 is connected to the compressed gas outlet of the last sub-compressor 140', and the compressed gas outlet can be connected to other subsequent carbon dioxide processing sections for subsequent storage and transportation. Along the direction of working fluid flow, the working fluid inlet 851a of the first interstage heat exchanger 851 is connected to the source component of the low-temperature liquid working fluid (for example, the corresponding throttle valve) through a pipeline, the working fluid outlet 851b of the last interstage heat exchanger 851 is connected to the corresponding working fluid compressor, and the working fluid outlet 851b of each interstage heat exchanger 851 between the first and the last is connected to the working fluid inlet 851a of the next adjacent sub-heat exchanger interstage heat exchanger 851.

[0092] In some optional embodiments, the power source of the regeneration gas compression device 140 is electrical energy, or high-temperature and high-pressure gas.

[0093] Figure 6 Schematic diagram of the structure of a carbon dioxide capture system 10 according to an embodiment of the present invention.

[0094] See also Figure 6 As shown, in some embodiments, the carbon dioxide capture system 10 of the utility model may include an absorption tower 110, a lean-rich liquid heat exchanger 120, and the aforementioned heat pump type waste heat regeneration module 600. The cold rich liquid inlet 121, the hot rich liquid outlet 122, the hot lean liquid inlet 123 and the cold lean liquid outlet 124 of the lean-rich liquid heat exchanger 120 are respectively connected to the rich liquid outlet 111 of the absorption tower 110, the first rich liquid feed inlet 131 of the desorption tower 130, the hot lean liquid outlet 132 of the desorption tower 130 and the lean liquid feed inlet 112 of the absorption tower 110 through pipelines.

[0095] Figure 7 It is a schematic structural block diagram of a carbon dioxide capture system 10 according to an embodiment of the present invention. Figure 8 It is a schematic structural block diagram of a carbon dioxide capture system 10 according to another embodiment of the present invention.

[0096] See also Figure 7 As shown, the carbon dioxide capture system 10 may generally include an absorption tower 110 , a lean and rich liquid heat exchanger 120 , and a desorption tower 130 .

[0097] The absorption tower 110 has a lean liquid feed inlet 112 and a rich liquid outlet 111 at the bottom. The absorption tower 110 may also have a flue gas inlet 115 (eg, Figure 2 As shown). The desorption tower 130 has a first rich liquid feed inlet 131 and a hot lean liquid outlet 132 at the bottom. The first rich liquid feed inlet 131 is arranged on the tower body of the desorption tower 130, and can be located in the middle or upper middle part of the tower body, depending on the feed temperature of the rich liquid. The cold rich liquid inlet 121, the hot rich liquid outlet 122, the hot lean liquid inlet 123 and the cold lean liquid outlet 124 of the lean-rich liquid heat exchanger 120 are respectively connected to the rich liquid outlet 111 of the absorption tower 110, the first rich liquid feed inlet 131 of the desorption tower 130, the hot lean liquid outlet 132 of the desorption tower 130 and the lean liquid feed inlet 112 of the absorption tower 110 through pipelines.

[0098] The carbon dioxide capture system 10 also includes a first heat pump type waste heat recovery and utilization component 15, which includes a first waste heat recovery heat pump 150 and a first waste heat utilization device 160; a first diverter 200; and a second heat pump type waste heat recovery and utilization component 25, which includes: a second waste heat recovery heat pump 250 and a second waste heat utilization device 260.

[0099] The first waste heat recovery heat pump 150 includes a first waste heat recovery heat exchanger 151 disposed in a pipeline between the cold lean liquid outlet 124 of the lean-rich liquid heat exchanger 120 and the lean liquid feed port 112 of the absorption tower 110. The first waste heat recovery heat pump 150 is configured to recover lean liquid waste heat based on heat exchange between the first heat pump working fluid and the lean liquid in the first waste heat recovery heat exchanger 151.

[0100] The first waste heat utilization device 160 is connected to the working fluid loop of the first waste heat recovery heat pump 150 and is connected to the bottom of the desorption tower 130. It is configured to utilize the recovered lean liquid waste heat to heat the medium lean liquid at the bottom of the desorption tower 130 through heat exchange to desorb carbon dioxide.

[0101] The first splitter 200 is disposed in a pipeline between the hot lean liquid outlet 132 of the desorption tower 130 and the hot lean liquid inlet 123 of the lean-rich liquid heat exchanger 120 , and is configured to split the hot lean liquid output from the desorption tower 130 .

[0102] The second waste heat recovery heat pump 250 includes a second waste heat recovery heat exchanger 251 disposed between the first flow splitter 200 and the first waste heat recovery heat exchanger 151. The second waste heat recovery heat exchanger 251 is configured to allow the second heat pump working fluid to perform heat exchange with the lean liquid of the split flow to absorb heat, and output the lean liquid after heat exchange to the first waste heat recovery heat exchanger 151.

[0103] The second waste heat utilization device 260 is connected to the working fluid loop of the second waste heat recovery heat pump 250 and is connected to the bottom of the desorption tower 130. It is configured to use the heat of the second heat pump working fluid to heat the lean liquid at the bottom of the desorption tower 130 through heat exchange to desorb carbon dioxide.

[0104] In the carbon dioxide capture system 10 provided in the embodiment of the utility model, the hot lean liquid output from the desorption tower 130 is diverted by the first diverter 200, and the diverted hot lean liquid in the high temperature section and the lean liquid in the medium temperature section cooled by the lean-rich liquid heat exchanger are respectively recovered by the second waste heat recovery heat pump 250 and the first waste heat recovery heat pump 150 for waste heat recovery, and the recovered waste heat is respectively used to heat the medium lean liquid at the bottom of the desorption tower 130 for carbon dioxide desorption, thereby realizing the cascade utilization of the lean liquid waste heat, so as to achieve the purpose of fully utilizing the lean liquid waste heat.

[0105] See also Figure 8 As shown, in some embodiments, the carbon dioxide capture system 10 may further include a second splitter 100. The desorption tower 130 also has a second rich liquid feed inlet 136. Similarly, the second rich liquid feed inlet 136 may be located in the middle or upper middle portion of the tower body, depending on the feed temperature of the rich liquid passing therethrough.

[0106] The second splitter 100 is disposed in a pipeline between the rich liquid outlet 111 of the absorption tower 110 and the cold rich liquid inlet 121 of the lean-rich liquid heat exchanger 120 , and is configured to split the rich liquid output from the absorption tower 110 .

[0107] The first heat pump type waste heat recovery and utilization component 15 may also include a first coupling heat exchanger 180. The first coupling heat exchanger 180 is connected to the working medium loop of the first waste heat recovery heat pump 150 and is located downstream of the first waste heat utilization device 160, and is respectively connected to the second splitter 100 and the second rich liquid feed port 136 of the desorption tower 130, and is configured to make the working medium output from the first waste heat utilization device 160 and the rich liquid diverted from the second splitter 100 perform heat exchange therein, and output the heat-exchanged rich liquid to the second rich liquid feed port 136 of the desorption tower 130. The working medium after heat exchange circulates in the working medium loop of the first waste heat recovery heat pump 150.

[0108] In the carbon dioxide capture system 10 with cascaded utilization of waste heat of the lean liquid provided in the embodiment of the utility model, the heat energy recovered from the lean liquid in the medium temperature section is recycled through the first coupling heat exchanger 180, and the working fluid after carbon dioxide desorption is further heat exchanged with the diverted cold rich liquid to preheat the cold rich liquid, thereby realizing coupled utilization of energy inside the carbon dioxide capture system and effectively reducing the heat consumption and operating cost of the carbon dioxide capture system.

[0109] In some optional embodiments, the first waste heat recovery heat pump 150 and the second waste heat recovery heat pump 250 may both be compression heat pumps. Compared with the waste heat recovery absorption heat pump commonly used in the prior art, the compression heat pump has a higher COP.

[0110] According to the temperature level of the recovered waste heat and the temperature level to which it is desired to be raised, the first waste heat recovery heat pump 150 and the second waste heat recovery heat pump 250 may be selected as single-stage or multi-stage compression heat pumps.

[0111] In some optional embodiments, since the lean liquid after cooling by the lean-rich liquid heat exchanger is in the medium temperature section, the first waste heat recovery heat pump 150 can be a single-stage or multi-stage compression heat pump to fully improve the quality of the recovered waste heat. Since the diverted hot lean liquid is in the high temperature section, the second waste heat recovery heat pump 250 can be a single-stage compression heat pump, which can reduce equipment costs while meeting the requirements of recovering waste heat and improving its quality.

[0112] Fig. 9 FIG. 1 is a structural schematic diagram of a carbon dioxide capture system 10 according to an embodiment of the present invention.

[0113] See also Fig. 9As shown, in some optional embodiments, the first waste heat recovery heat pump 150 is a two-stage compression heat pump, which includes a first heat pump unit and a second heat pump unit. The first heat pump unit includes a first waste heat recovery heat exchanger 151, a first working fluid compressor 152, a first working fluid heat exchanger 153 and a first throttle valve 154, which are sequentially connected through pipelines to form a first working fluid loop 157 for the first heat pump working fluid to circulate. The second heat pump unit includes a first working fluid heat exchanger 153, a second working fluid compressor 155 and a second throttle valve 156, which are sequentially connected through pipelines to form a second working fluid loop 158 for the third heat pump working fluid to circulate. The first waste heat utilization device 160 and the first coupling heat exchanger 180 are sequentially connected in the pipeline between the second working fluid compressor 155 and the second throttle valve 156 according to the flow direction of the third heat pump working fluid.

[0114] The first working fluid loop 157 is configured to allow the first heat pump working fluid to flow into the first waste heat recovery heat exchanger 151 in liquid form to absorb the lean liquid waste heat and then undergo a phase change to become steam, and then enter the first working fluid heat exchanger 153 after being compressed by the first working fluid compressor 152 to exchange heat with the liquid third heat pump working fluid, and then pass through the first throttle valve 154 for throttling and cooling to become liquid, and then flow into the first waste heat recovery heat exchanger 151.

[0115] The second working fluid loop 158 is configured to allow the third heat pump working fluid to flow into the first working fluid heat exchanger 153 in liquid form, undergo a phase change and be converted into steam after heat exchange with the first heat pump working fluid, and then enter the first waste heat utilization device 160 after being compressed by the second working fluid compressor 155 to heat the lean liquid at the bottom of the desorption tower 130, and then enter the first coupling heat exchanger 180 to exchange heat with the diverted rich liquid, and then pass through the second throttle valve 156 for throttling and cooling to be converted into liquid, and then flow into the first working fluid heat exchanger 153.

[0116] In this embodiment, a two-stage compression heat pump is used to fully improve the quality of the recovered medium-temperature section lean liquid waste heat.

[0117] The first heat pump working fluid and the third heat pump working fluid can be selected according to actual application requirements. In some embodiments, for example, the first heat pump working fluid can be 1663mz, and the third heat pump working fluid can be R245fa.

[0118] Continue to see Fig. 9 In some optional embodiments, the second waste heat recovery heat pump 250 includes a second waste heat recovery heat exchanger 251, a third working medium compressor 252 and a third throttle valve 253 which are sequentially connected through pipelines to form a third working medium loop 254 for circulating the second heat pump working medium. The second waste heat utilization device 260 is connected in the pipeline between the third working medium compressor 252 and the third throttle valve 253.

[0119] The third working fluid loop 254 is configured to allow the second heat pump working fluid to flow into the second waste heat recovery heat exchanger 251 in liquid form, exchange heat with the lean liquid in the branched path, undergo a phase change and be converted into steam, and then enter the second waste heat utilization device 260 after being compressed by the third working fluid compressor 252 to heat the lean liquid at the bottom of the desorption tower 130, and then pass through the third throttle valve 253 for throttling and cooling to be converted into liquid form, and then flow into the second waste heat recovery heat exchanger 251.

[0120] In this embodiment, the waste heat of the split hot lean liquid in the high temperature section is recovered in an economical and efficient manner through a single-stage compression heat pump.

[0121] The second heat pump working fluid can be selected according to actual application requirements. In some embodiments, for example, the second heat pump working fluid can be R245fa or water.

[0122] Fig.11 It is a partial structural diagram of a carbon dioxide capture system 10 according to an embodiment of the present invention, wherein for the sake of simplicity of illustration, other components not related to the absorption reaction heat recovery of the absorption tower 110 are omitted.

[0123] See also Fig.11 As shown, in some optional embodiments, the carbon dioxide capture system 10 may further include a third waste heat recovery heat exchanger 641, whose absorbent inlet 351a and absorbent outlet 351b are respectively connected to the absorbent outlet 113 and the absorbent return port 114 of the absorption tower 110, and whose working fluid inlet 351c and working fluid outlet 351d are connected to the working fluid loop of the first waste heat recovery heat pump 150 in parallel with the working fluid inlet and working fluid outlet of the first waste heat recovery heat exchanger 151, so that the first heat pump working fluid is divided into the first waste heat recovery heat exchanger 151 and the third waste heat recovery heat exchanger 641, and the first heat pump working fluid flowing out of the first waste heat recovery heat exchanger 151 and the third waste heat recovery heat exchanger 641 is combined and circulated. The third waste heat recovery heat exchanger 641 is configured to perform heat exchange between the absorbent drawn from the absorption tower 110 and the first heat pump working fluid entering it.

[0124] In this embodiment, the third waste heat recovery heat exchanger 641 is integrated into the first waste heat recovery heat pump 150, so that the waste heat of the lean liquid and the reaction waste heat of the absorption liquid can be recovered simultaneously through a compression heat pump, which simplifies the equipment structure and saves equipment costs. In addition, the working fluid replaces the traditional cooling water to achieve the cooling function of the lean liquid, the absorption liquid, etc., thereby greatly reducing the cooling water consumption in the carbon dioxide capture process and further reducing the carbon capture operating cost.

[0125] Fig.10 FIG. 1 is a structural schematic diagram of a carbon dioxide capture system 10 according to an embodiment of the present invention.

[0126] See also Fig.10As shown, in some optional embodiments, the carbon dioxide capture system 10 may further include a third heat pump type waste heat recovery component 35 , which includes a third waste heat recovery heat pump 350 and a third waste heat utilization device 360 ​​.

[0127] The third waste heat recovery heat pump 350 includes a fourth waste heat recovery heat exchanger 351 disposed between the absorbent outlet 113 and the absorbent return port 114 of the absorption tower 110. The third waste heat recovery heat pump 350 is configured to recover the absorption reaction waste heat of the absorption tower 110 by exchanging heat with the absorbent drawn from the absorption tower 110 in the fourth waste heat recovery heat exchanger 351 based on the fourth heat pump working fluid.

[0128] The third waste heat utilization device 360 ​​is connected to the working fluid loop of the third waste heat recovery heat pump 350 and is connected to the bottom of the desorption tower 130. It is configured to utilize the recovered absorption reaction waste heat to heat the lean liquid at the bottom of the desorption tower 130 through heat exchange to desorb carbon dioxide.

[0129] In some further embodiments, the carbon dioxide capture system 10 may further include a second coupled heat exchanger 280. The second coupled heat exchanger 280 is connected to the working fluid loop of the third waste heat recovery heat pump 350 and is located downstream of the third waste heat utilization device 360, and is respectively connected to the second splitter 100 and the third rich liquid feed port 137 of the desorption tower 130, and is configured to make the working fluid output from the third waste heat utilization device 360 ​​and another rich liquid diverted from the second splitter 100 perform heat exchange therein, and output the heat-exchanged rich liquid to the third rich liquid feed port 137 of the desorption tower 130. The working fluid after heat exchange circulates in the working fluid loop of the third waste heat recovery heat pump 350.

[0130] In this embodiment, by providing an independent third waste heat recovery heat pump 350, the reaction waste heat of the absorption liquid can be recovered in a targeted manner, thereby realizing efficient recovery and quality improvement of the reaction waste heat of the absorption liquid. At the same time, while recovering the waste heat of the lean liquid and the reaction waste heat of the absorption liquid, the working fluid replaces the traditional cooling water to realize the cooling function of the lean liquid, the absorption liquid, etc., thereby greatly reducing the cooling water consumption in the carbon dioxide capture process and further reducing the carbon capture operation cost.

[0131] In some optional embodiments, the third waste heat recovery heat pump 350 may be a single-stage or multi-stage compression heat pump according to the temperature level of the recovered waste heat and the temperature level to which it is desired to be raised.

[0132] Continue to see Fig.10In some optional embodiments, the third waste heat recovery heat pump 350 is a two-stage compression heat pump, which includes a third heat pump unit and a fourth heat pump unit. The third heat pump unit includes a fourth waste heat recovery heat exchanger 351, a fourth working fluid compressor 352, a second working fluid heat exchanger 353 and a fourth throttle valve 354, which are sequentially connected through pipelines to form a fourth working fluid loop 357 for circulating the fourth heat pump working fluid. The fourth heat pump unit includes a second working fluid heat exchanger 353, a fifth working fluid compressor 355 and a fifth throttle valve 356, which are sequentially connected through pipelines to form a fifth working fluid loop 358 for circulating the fifth heat pump working fluid. The third waste heat utilization device 360 ​​and the second coupling heat exchanger 280 are sequentially connected in the pipeline between the fifth working fluid compressor 355 and the fifth throttle valve 356 according to the flow direction of the fifth heat pump working fluid.

[0133] The fourth working fluid loop 357 is configured to allow the fourth heat pump working fluid to flow into the fourth waste heat recovery heat exchanger 351 in liquid form to absorb the reaction waste heat, undergo a phase change and be converted into steam, be compressed by the fourth working fluid compressor 352, enter the second working fluid heat exchanger 353 to exchange heat with the liquid fifth heat pump working fluid, then pass through the fourth throttle valve 354 for throttling and cooling to be converted into liquid form, and then flow into the fourth waste heat recovery heat exchanger 351.

[0134] The fifth working fluid loop 358 is configured to allow the fifth heat pump working fluid to flow into the second working fluid heat exchanger 353 in liquid form, undergo a phase change and be converted into steam after heat exchange with the fourth heat pump working fluid, and then enter the third waste heat utilization device 360 ​​after being compressed by the fifth working fluid compressor 355 to heat the lean liquid at the bottom of the desorption tower 130, and then enter the second coupled heat exchanger 280 to exchange heat with another rich liquid diverted out, and then pass through the fifth throttle valve 356 for throttling and cooling to be converted into liquid form, and then flow into the second working fluid heat exchanger 353.

[0135] In this embodiment, a two-stage compression heat pump is used to fully improve the quality of the reaction waste heat of the recovered absorption liquid.

[0136] The fourth heat pump working fluid and the fifth heat pump working fluid can be selected according to actual application requirements. In some embodiments, for example, the fourth heat pump working fluid can be 1663mz, and the fifth heat pump working fluid can be R245fa.

[0137] It should be noted that, in order to facilitate the purpose of the third waste heat recovery heat exchanger 641 to recover the absorption reaction heat in the absorption tower 110, Fig.11The third waste heat recovery heat exchanger 641 is shown as being disposed in the absorption tower 110, but this does not mean that the third waste heat recovery heat exchanger 641 must be disposed in the absorption tower 110. Those skilled in the art can understand that the third waste heat recovery heat exchanger 641 can be disposed outside the absorption tower 110, and the absorbent in the absorption tower 110 is introduced into the third waste heat recovery heat exchanger 641 through the absorbent outlet 113 and the absorbent return port 114 of the absorption tower 110 for heat exchange and then the absorbent is returned to the absorption tower 110.

[0138] In some optional embodiments, the third waste heat recovery heat exchanger 641 or the fourth waste heat recovery heat exchanger 351 may include a plurality of sub-heat exchangers 351', and these sub-heat exchangers 351' may be connected in parallel or in series. Here, a plurality refers to 2 or more.

[0139] Fig.12 FIG. 6 is a schematic diagram of a third waste heat recovery heat exchanger 641 or a fourth waste heat recovery heat exchanger 351 using multi-stage parallel sub-heat exchangers according to an embodiment of the present invention. Figure 6 As shown, when multiple sub-heat exchangers 351' are connected in parallel, the absorbent inlet 351a and the absorbent outlet 351b of each sub-heat exchanger 351' are respectively connected to the corresponding absorbent outlet 113 and the absorbent return port 114 on the absorption tower 110. The working fluid inlet 351c of each sub-heat exchanger 351' can be connected to the working fluid loop connected to the third waste heat recovery heat exchanger 641 or the fourth waste heat recovery heat exchanger 351 through a pipeline to receive the inflow of low-temperature liquid working fluid. The working fluid outlet 351d of each sub-heat exchanger 351' can also be connected to the working fluid loop connected to the third waste heat recovery heat exchanger 641 or the fourth waste heat recovery heat exchanger 351 to return the working fluid after heat exchange to the working fluid loop for circulation.

[0140] Fig.13 FIG. 6 is a schematic diagram of a third waste heat recovery heat exchanger 641 or a fourth waste heat recovery heat exchanger 351 using a multi-stage series sub-heat exchanger according to an embodiment of the present invention. Figure 7As shown, in the case where multiple sub-heat exchangers 351' are connected in series, the absorbent inlet 351a and the absorbent outlet 351b of each sub-heat exchanger 351' are respectively connected to the corresponding absorbent outlet 113 and the absorbent return port 114 on the absorption tower 110. Along the direction of the working medium flow, the working medium inlet 351c of the first sub-heat exchanger 351' is connected to the working medium loop connected to the third waste heat recovery heat exchanger 641 or the fourth waste heat recovery heat exchanger 351 through a pipeline to receive the inflow of low-temperature liquid working medium, the working medium outlet 351d of the last sub-heat exchanger 351' is connected to the working medium loop connected to the third waste heat recovery heat exchanger 641 or the fourth waste heat recovery heat exchanger 351, and the working medium outlet 351d of each sub-heat exchanger 351' between the first and the last is connected to the working medium inlet 351c of the next adjacent sub-heat exchanger 351'.

[0141] In the embodiment of the utility model, the second flow divider 100 and the first flow divider 200 can adopt a variety of flow dividing devices, such as a multi-way flow dividing valve, etc. In some embodiments, different combinations of flow dividing devices can also be adopted according to the number of rich liquid or lean liquid flow paths that are finally divided. Fig.10 As shown, if the rich liquid needs to be divided into four rich liquid diversions, two three-way valves 100 can be combined as a diverter. The specific diverters 100 and 200 can be selected and combined according to actual application requirements, and the utility model does not make specific restrictions on this.

[0142] In some optional embodiments, a fourth rich liquid feed port 138 is provided at the top of the desorption tower 130. The fourth rich liquid feed port 138 is connected to an outlet of the diverter 100, so that one path of rich liquid diverted by the diverter 100 directly enters the desorption tower 130 via the fourth rich liquid feed port 138. In this embodiment, a portion of the carbon dioxide rich liquid flowing out of the bottom of the absorption tower 110 is diverted and directly enters the desorption tower 130, and energy recovery is performed inside the desorption tower, thereby further improving energy recovery and utilization efficiency.

[0143] In some optional embodiments, the desorption tower 130 also includes a regeneration gas outlet 133 located at the top. The carbon dioxide capture system 10 may also include a regeneration gas cooler 190 and a gas-liquid separator 191 connected in sequence to the regeneration gas outlet 133. The liquid outlet of the gas-liquid separator 191 is connected to the liquid return port at the top of the desorption tower 130. The carbon dioxide regeneration gas flowing out of the regeneration gas outlet 133 enters the regeneration gas cooler 190 for condensation, and then enters the gas-liquid separator 191 for gas-liquid separation. The condensed and separated liquid returns to the desorption tower 130 from the liquid return port.

[0144] In some optional embodiments, the carbon dioxide capture system 10 may further include a fourth heat pump type waste heat recovery component 45. The fourth heat pump type waste heat recovery component 45, the desorption tower 130 and the regeneration gas compression device 140 constitute a heat pump type waste heat regeneration module 600.

[0145] Fig.14 FIG. 1 is a schematic diagram of the structure of a carbon dioxide capture system 10 according to an embodiment of the present invention. Fig.14 As shown, in some embodiments, the carbon dioxide capture system 10 may include a first heat pump type waste heat recovery component 15, a second heat pump type waste heat recovery component 25, a third heat pump type waste heat recovery component 35, and a fourth heat pump type waste heat recovery component 45. The specific structures of these heat pump type waste heat recovery components are as described above and will not be repeated here.

[0146] In some embodiments of the present invention, an absorbent is also provided. The absorbent is a CO2 composite absorbent comprising a cyclic organic amine, a sterically hindered amine, a metal complexing agent and water. The CO2 composite absorbent can be applied to a carbon dioxide capture system 10 that performs self-heat recovery after diverting the hot lean liquid output from the desorption tower 130 through the first diverter 200.

[0147] In some embodiments, the total mass proportion of the cyclic organic amine, sterically hindered amine and metal complexing agent in the composite absorbent may be 20-60%, for example, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%.

[0148] In some preferred embodiments, the total mass proportion of the cyclic organic amine, the sterically hindered amine and the metal complexing agent in the composite absorbent may be 30-40%.

[0149] In some specific embodiments, the CO2 composite absorbent comprises, by mass: 8-25% of a cyclic organic amine, 10-35% of a sterically hindered amine, 0.1-2.0% of a metal complexing agent and the remainder of water.

[0150] In some more specific embodiments, the mass proportion of the cyclic organic amine in the CO2 composite absorbent may be 10%, 12%, 15%, 18%, 20%, 22%, etc.

[0151] In some more specific embodiments, the mass proportion of the sterically hindered amine in the CO2 composite absorbent may be 12%, 15%, 18%, 20%, 22%, 25%, 27%, 30%, 33%, etc.

[0152] In some more specific embodiments, the mass proportion of the metal complexing agent in the CO2 composite absorbent may be 0.3%, 0.5%, 0.7%, 1.0%, 1.2%, 1.5%, 1.8%, etc.

[0153] In some optional embodiments, the cyclic organic amine can be a mixture of one or more of piperazine, N-hydroxyethylpiperazine, 1-(2-hydroxyethyl)-4-aminopiperidine, 4-hydroxy-1-methylpiperidine, 3-aminomethylpyridine, N-aminoethylpiperazine, and aniline.

[0154] In some optional embodiments, the sterically hindered amine may be a mixture of one or more of 2-amino-2-methyl-1-propanol, isopropanolamine, sodium aminoisobutyrate, and 2-amino-2-ethyl-1,3-propanediol.

[0155] In some optional embodiments, the metal complexing agent may be one of ethylenediaminetetraacetic acid, tartaric acid tetrahydrate, or a mixture thereof.

[0156] The carbon capture performance of different absorbent formulations is compared below, see Table 1 for details.

[0157] Table 1

[0158]

[0159] The proportions in Table 1 are all mass proportions, and each formula contains 0.5% ethylenediaminetetraacetic acid and 0.5% tartaric acid tetrahydrate. The saturated CO2 load was determined by the bubbling method at a CO2 volume concentration of 10%; the average CO2 absorption rate was determined by the bubbling method at a CO2 volume concentration of 10%, and the CO2 system concentration at the outlet was monitored in real time during the experiment; the CO2 reaction heat was measured by the C80 microcalorimeter to measure the Joule heat, and then the average CO2 reaction heat was obtained by integration; the desorption temperature was obtained by Aspen Plus simulation under 2 bar conditions; the desorption energy consumption was obtained by calculating the reaction heat, sensible heat and latent heat, of which the sensible heat was obtained by Aspen Plus simulation under the condition of 5K for the lean and rich liquid heat exchanger, and the latent heat was calculated by Aspen Plus simulation under the condition of rich liquid diversion optimization according to the temperature and the molar ratio of CO2 / H2O.

[0160] As can be seen from Table 1, the composite absorbent of cyclic organic amine and sterically hindered amine is superior to the benchmark ethanolamine absorbent in key performances such as CO2 load, CO2 absorption rate, CO2 reaction heat and desorption energy consumption. The reason is that the cyclic organic amine contains a polyamine structure, and the concentration of amine groups per unit mole of molecules is significantly higher than that of monoethanolamine, which increases the CO2 absorption rate and absorption capacity; at the same time, the sterically hindered amine doubles its theoretical CO2 absorption capacity compared to primary ethanolamine by accepting reaction protons. Therefore, the composite absorbent increases the CO2 absorption amount and absorption rate per unit mass of solvent, while reducing the CO2 reaction heat and the desorption temperature and heat energy consumption during the solvent regeneration process. In the utility model, after coupling with the heat pump process, the temperature difference between the cold end and the hot end is reduced, the COP performance of the heat pump is improved, the heat pump load and electrical energy efficiency are reduced, and the energy utilization efficiency of the carbon capture system is improved as a whole.

[0161] Furthermore, in some implementation cases, in order to increase the long-term stable operation performance of the absorbent, antioxidants, anti-corrosion agents and anti-foaming agents are added to the absorbent.

[0162] Specifically, by mass, the content of antioxidant in the absorbent is 0.1-1%, for example, 0.2%, 0.4%, 0.5%, 0.7%, 0.9% and the like; the content of corrosion inhibitor is 0.1-1%, for example, 0.2%, 0.4%, 0.5%, 0.7%, 0.9% and the like; the content of anti-foaming agent is 0.01-0.1%, for example, 0.02%, 0.03%, 0.05%, 0.06%, 0.08% and the like.

[0163] In some specific embodiments, the antioxidant is a mixture of one or more of sodium metavanadate, potassium bismuth citrate, and sodium antimony gluconate. The corrosion inhibitor is a mixture of one or more of sodium molybdate, sodium tungstate, thiourea, sodium vanadate, potassium orthophosphate, sodium borate, and diethanolglycine. The anti-foaming agent is one of dimethyl silicone oil and polypropylene glycol or a mixture thereof.

[0164] Fig.15 1 is a schematic structural block diagram of a carbon dioxide capture system 10 according to an embodiment of the present invention, wherein the carbon dioxide capture system 10 recovers and utilizes waste heat by a heat pump.

[0165] See also Fig.15 As shown, the carbon dioxide capture system 10 may generally include an absorption tower 110 , a lean and rich liquid heat exchanger 120 , and a desorption tower 130 .

[0166] The absorption tower 110 has a lean liquid feed inlet 112 and a rich liquid outlet 111 at the bottom. The absorption tower 110 may also have a flue gas inlet 115 (eg, Fig.16As shown). The desorption tower 130 has a first rich liquid feed inlet 131 and a hot lean liquid outlet 132 at the bottom. The first rich liquid feed inlet 131 is arranged on the tower body of the desorption tower 130, and can be located in the middle or upper middle part of the tower body, depending on the feed temperature of the rich liquid. The cold rich liquid inlet 121, the hot rich liquid outlet 122, the hot lean liquid inlet 123 and the cold lean liquid outlet 124 of the lean-rich liquid heat exchanger 120 are respectively connected to the rich liquid outlet 111 of the absorption tower 110, the first rich liquid feed inlet 131 of the desorption tower 130, the hot lean liquid outlet 132 of the desorption tower 130 and the lean liquid feed inlet 112 of the absorption tower 110 through pipelines.

[0167] The carbon dioxide capture system 10 also includes: a second diverter 100, which is arranged in the pipeline between the rich liquid outlet 111 of the absorption tower 110 and the cold rich liquid inlet 121 of the lean-rich liquid heat exchanger 120, and is configured to divert the rich liquid output by the absorption tower 110; and at least one of the first heat pump type waste heat recovery and utilization component 15 and the third heat pump type waste heat recovery and utilization component 35.

[0168] The first heat pump type waste heat recovery and utilization component 15 may include a first waste heat recovery heat pump 150 , a first waste heat utilization device 160 , and a first coupling heat exchanger 180 .

[0169] The first waste heat recovery heat pump 150 includes a first waste heat recovery heat exchanger 151 disposed in a pipeline between the cold lean liquid outlet 124 of the lean-rich liquid heat exchanger 120 and the lean liquid feed port 112 of the absorption tower 110. The first waste heat recovery heat pump 150 is configured to recover lean liquid waste heat based on heat exchange between the first heat pump working fluid and the lean liquid in the first waste heat recovery heat exchanger 151.

[0170] The first waste heat utilization device 160 is connected to the working fluid loop of the first waste heat recovery heat pump 150 and is connected to the bottom of the desorption tower 130. It is configured to utilize the recovered lean liquid waste heat to heat the medium lean liquid at the bottom of the desorption tower 130 through heat exchange to desorb carbon dioxide.

[0171] The first coupling heat exchanger 180 is connected to the working fluid loop of the first waste heat recovery heat pump 150 and is located downstream of the first waste heat utilization device 160. It is respectively connected to the second diverter 100 and the second rich liquid feed port 136 of the desorption tower 130. It is configured to allow the working fluid output from the first waste heat utilization device 160 to exchange heat with the rich liquid diverted from the second diverter 100, and output the rich liquid after heat exchange to the second rich liquid feed port 136 of the desorption tower 130.

[0172] The third heat pump type waste heat recovery and utilization component 35 includes a third waste heat recovery heat pump 350 , a third waste heat utilization device 360 ​​and a second coupling heat exchanger 280 .

[0173] The third waste heat recovery heat pump 350 includes a fourth waste heat recovery heat exchanger 351 disposed between the absorbent outlet and the absorbent return outlet of the absorption tower 110. The third waste heat recovery heat pump 350 is configured to perform heat exchange with the absorbent drawn from the absorption tower 110 in the fourth waste heat recovery heat exchanger 351 based on the fourth heat pump working fluid to recover the absorption reaction waste heat of the absorption tower 110.

[0174] The third waste heat utilization device 360 ​​is connected to the working fluid loop of the third waste heat recovery heat pump 350 and is connected to the bottom of the desorption tower 130. It is configured to utilize the recovered absorption reaction waste heat to heat the lean liquid at the bottom of the desorption tower 130 through heat exchange to desorb carbon dioxide.

[0175] The second coupling heat exchanger 280 is connected to the working fluid loop of the third waste heat recovery heat pump 350 and is located downstream of the third waste heat utilization device 360. It is respectively connected to the second diverter 100 and the third rich liquid feed port 137 of the desorption tower 130. It is configured to allow the working fluid output from the third waste heat utilization device 360 ​​to exchange heat with the rich liquid diverted from the second diverter 100, and output the rich liquid after heat exchange to the third rich liquid feed port 137 of the desorption tower 130.

[0176] In this embodiment, the first heat pump type waste heat recovery and utilization component 15 and / or the third heat pump type waste heat recovery and utilization component 35 are used to recover and improve the quality of the lean liquid waste heat and / or the reaction waste heat of the absorption liquid in the carbon dioxide capture system after cooling through the lean and rich liquid heat exchanger, thereby improving the energy efficiency of the system. At the same time, the residual energy after carbon dioxide desorption is fully utilized by coupling the heat exchanger to preheat the cold rich liquid diverted, thereby realizing the coupled utilization of the internal energy of the carbon dioxide capture system and effectively reducing the heat consumption and operating cost of the carbon dioxide capture system.

[0177] It should be noted that Fig.15 The first heat pump type waste heat recovery component 15 and the third heat pump type waste heat recovery component 35 are only shown as examples, but it does not mean that the first heat pump type waste heat recovery component 15 and the third heat pump type waste heat recovery component 35 must be provided in the carbon dioxide capture system 10. Those skilled in the art should be aware that only one of the first heat pump type waste heat recovery component 15 and the third heat pump type waste heat recovery component 35 can be provided in the carbon dioxide capture system 10.

[0178] In some optional embodiments, the first waste heat recovery heat pump 150 may be a single-stage or multi-stage compression heat pump.

[0179] Fig.16 FIG. 1 is a structural schematic diagram of a carbon dioxide capture system 10 according to an embodiment of the present invention.

[0180] See also Fig.16 As shown, in some embodiments, the first waste heat recovery heat pump 150 is a two-stage compression heat pump. The first waste heat recovery heat pump 150 includes a first heat pump unit and a second heat pump unit. The first heat pump unit includes a first waste heat recovery heat exchanger 151, a first working fluid compressor 152, a first working fluid heat exchanger 153 and a first throttle valve 154 that are sequentially connected through pipelines to form a first working fluid loop 157 for the first heat pump working fluid to circulate. The second heat pump unit includes a first working fluid heat exchanger 153, a second working fluid compressor 155 and a second throttle valve 156 that are sequentially connected through pipelines to form a second working fluid loop 158 for the third heat pump working fluid to circulate.

[0181] The first waste heat utilization device 160 and the first coupling heat exchanger 180 are sequentially connected in the pipeline between the second working medium compressor 155 and the second throttle valve 153 according to the flow direction of the third heat pump working medium.

[0182] The first working fluid loop 157 is configured to allow the first heat pump working fluid to flow into the first waste heat recovery heat exchanger 151 in liquid form to absorb the lean liquid waste heat and then undergo a phase change to become steam, and then enter the first working fluid heat exchanger 153 after being compressed by the first working fluid compressor 152 to exchange heat with the liquid third heat pump working fluid, and then pass through the first throttle valve 154 for throttling and cooling to become liquid, and then flow into the first waste heat recovery heat exchanger 151.

[0183] The second working fluid loop 158 is configured to allow the third heat pump working fluid to flow into the first working fluid heat exchanger 153 in liquid form, undergo a phase change and be converted into steam after heat exchange with the first heat pump working fluid, and then enter the first waste heat utilization device 160 after being compressed by the second working fluid compressor 155 to heat the lean liquid at the bottom of the desorption tower 130, and then enter the first coupling heat exchanger 180 to exchange heat with the diverted rich liquid, and then pass through the second throttle valve 156 for throttling and cooling to be converted into liquid, and then flow into the first working fluid heat exchanger 153.

[0184] In this embodiment, a two-stage compression heat pump is used to fully improve the quality of the recovered medium-temperature section lean liquid waste heat.

[0185] In some optional embodiments, the third waste heat recovery heat pump 350 may be a single-stage or multi-stage compression heat pump.

[0186] Fig. 20 FIG. 1 is a structural schematic diagram of a carbon dioxide capture system 10 according to an embodiment of the present invention.

[0187] See also Fig. 20As shown, in some embodiments, the third waste heat recovery heat pump 350 is a two-stage compression heat pump, including a third heat pump unit and a fourth heat pump unit. The third heat pump unit includes a fourth waste heat recovery heat exchanger 351, a fourth working fluid compressor 352, a second working fluid heat exchanger 353 and a fourth throttle valve 354, which are sequentially connected through pipelines to form a fourth working fluid loop 357 for circulating the fourth heat pump working fluid. The fourth heat pump unit includes a second working fluid heat exchanger 353, a fifth working fluid compressor 355 and a fifth throttle valve 356, which are sequentially connected through pipelines to form a fifth working fluid loop 358 for circulating the fifth heat pump working fluid.

[0188] The third waste heat utilization device 360 ​​and the second coupling heat exchanger 280 are sequentially connected in the pipeline between the fifth working medium compressor 355 and the fifth throttle valve 356 according to the flow direction of the fifth heat pump working medium.

[0189] The fourth working fluid loop 357 is configured to allow the fourth heat pump working fluid to flow into the fourth waste heat recovery heat exchanger 351 in liquid form to absorb the reaction waste heat, undergo a phase change and be converted into steam, be compressed by the fourth working fluid compressor 352, enter the second working fluid heat exchanger 353 to exchange heat with the liquid fifth heat pump working fluid, then pass through the fourth throttle valve 354 for throttling and cooling to be converted into liquid form, and then flow into the fourth waste heat recovery heat exchanger 351.

[0190] The fifth working fluid loop 358 is configured to allow the fifth heat pump working fluid to flow into the second working fluid heat exchanger 353 in liquid form, undergo a phase change and be converted into steam after heat exchange with the fourth heat pump working fluid, and then enter the third waste heat utilization device 360 ​​after being compressed by the fifth working fluid compressor 355 to heat the lean liquid at the bottom of the desorption tower 130, and then enter the second coupled heat exchanger 280 to exchange heat with another rich liquid diverted out, and then pass through the fifth throttle valve 356 for throttling and cooling to be converted into liquid form, and then flow into the second working fluid heat exchanger 353.

[0191] In this embodiment, a two-stage compression heat pump is used to fully improve the quality of the reaction waste heat of the recovered absorption liquid.

[0192] Fig.17 FIG. 1 is a schematic diagram of the structure of a carbon dioxide capture system 10 according to an embodiment of the present invention. Fig.17As shown, in some embodiments, the carbon dioxide capture system 10 further includes a gas-liquid separator 191, which is connected to the regeneration gas outlet 133 of the desorption tower 130 through a pipeline, and a regeneration gas compression device 140, which is connected to the gas outlet of the gas-liquid separator 191. The carbon dioxide capture system 10 may also include a fifth waste heat recovery heat exchanger 731, which is respectively connected to the second splitter 100, the regeneration gas compression device 140 and the fifth rich liquid feed port 139 of the desorption tower 130, and is configured to allow the rich liquid diverted from the second splitter 100 to exchange heat with the compressed regeneration gas generated by the regeneration gas compression device 140 therein, and output the rich liquid after heat exchange to the fifth rich liquid feed port 139.

[0193] In some optional embodiments, the carbon dioxide capture system 10 may further include a fourth heat pump type waste heat recovery component 45. The fourth heat pump type waste heat recovery component 45, the desorption tower 130 and the regeneration gas compression device 140 constitute a heat pump type waste heat regeneration module 600.

[0194] Fig.19 1 is a partial structural diagram of a carbon dioxide capture system 100 according to an embodiment of the present invention, wherein for the sake of simplicity of illustration, other components not related to the regeneration waste heat recovery of the desorption tower 130 are omitted.

[0195] For example, see Fig.19 As shown, in some embodiments, the carbon dioxide capture system 100 further includes a gas-liquid separator 191, which is connected to the regeneration gas outlet 133 of the desorption tower 130 through a pipeline, and a regeneration gas compression device 140, which is connected to the gas outlet of the gas-liquid separator 191. The gas-liquid separator 191 is connected between the regeneration gas outlet 133 and the regeneration gas compression device 140. The liquid outlet of the gas-liquid separator 191 is connected to the liquid return port at the top of the desorption tower 130. The carbon dioxide regeneration gas flowing out of the regeneration gas outlet 133 enters the gas-liquid separator 191 for gas-liquid separation. The separated liquid returns to the desorption tower 130 from the liquid return port.

[0196] The carbon dioxide capture system 100 may further include a fourth heat pump type waste heat recovery and utilization component 45. The fourth heat pump type waste heat recovery and utilization component 45 includes a fourth waste heat recovery heat pump 450 and a fourth waste heat utilization device 460. The fourth waste heat recovery heat pump 450 includes a sixth waste heat recovery heat exchanger 451 arranged in a pipeline between the regeneration gas outlet 133 of the desorption tower 130 and the gas-liquid separator 191 and a seventh waste heat recovery heat exchanger 452 connected to the regeneration gas compression device 140. The sixth waste heat recovery heat exchanger 451 is configured to allow the sixth heat pump working fluid to exchange heat with the regeneration gas output from the regeneration gas outlet 133 in the sixth waste heat recovery heat exchanger 451 to recover the waste heat of the regeneration gas. The seventh waste heat recovery heat exchanger 452 is configured to allow the sixth heat pump working fluid to exchange heat with the compressed regeneration gas generated by the regeneration gas compression device 140 in the seventh waste heat recovery heat exchanger 452 to recover the waste heat of the compressed regeneration gas. The fourth waste heat utilization device 460 is connected to the working fluid loop of the fourth waste heat recovery heat pump 450 and is connected to the bottom of the desorption tower 130. It is configured to utilize the recovered regeneration gas waste heat and the compressed regeneration gas waste heat to heat the lean liquid at the bottom of the desorption tower 130 through heat exchange to desorb carbon dioxide.

[0197] In some further embodiments (e.g. Figure 4 As shown in FIG. 1 , the fourth waste heat recovery heat pump 450 is a single-stage compression heat pump, which includes a seventh waste heat recovery heat exchanger 452, a sixth waste heat recovery heat exchanger 451, a sixth working medium compressor 453 and a sixth throttle valve 454, which are sequentially connected through pipelines to form a sixth working medium loop 455 for circulating the sixth heat pump working medium. The fourth waste heat utilization device 460 is connected in the pipeline between the sixth working medium compressor 453 and the sixth throttle valve 454.

[0198] The sixth working fluid loop 455 is configured to allow the sixth heat pump working fluid flowing out of the sixth throttle valve 454 to flow into the seventh waste heat recovery heat exchanger 452 and the sixth waste heat recovery heat exchanger 451 in liquid state in sequence to undergo phase change and be converted into steam after heat exchange with the compressed regeneration gas and the regeneration gas respectively, and then enter the sixth waste heat utilization device 460 after being compressed by the sixth working fluid compressor 453 to heat the lean liquid at the bottom of the desorption tower 130, and then pass through the sixth throttle valve 454 for throttling and cooling to be converted into liquid state, thereby completing the working fluid cycle.

[0199] In some further embodiments (e.g. Fig.19As shown in FIG. 1 , the fourth waste heat recovery heat pump 450 is a single-stage compression heat pump, including a seventh waste heat recovery heat exchanger 452, a sixth waste heat recovery heat exchanger 451, a sixth working fluid compressor 453 and a sixth throttle valve 454. The seventh waste heat recovery heat exchanger 452 and the sixth waste heat recovery heat exchanger 451 are connected in parallel and then sequentially connected to the sixth working fluid compressor 453 and the sixth throttle valve 454 through a pipeline to form a sixth working fluid loop 455 for circulating the working fluid of the sixth heat pump. The fourth waste heat utilization device 460 is connected in the pipeline between the sixth working fluid compressor 453 and the sixth throttle valve 454.

[0200] The sixth working fluid loop 455 is configured to allow the sixth heat pump working fluid flowing out of the sixth throttle valve 454 to be diverted in liquid form into the seventh waste heat recovery heat exchanger 452 and the sixth waste heat recovery heat exchanger 451 to undergo phase change and be converted into steam after heat exchange with the compressed regeneration gas and the regeneration gas respectively, and then enter the sixth waste heat utilization device 460 after being compressed by the sixth working fluid compressor 453 to heat the lean liquid at the bottom of the desorption tower 130, and then pass through the sixth throttle valve 454 for throttling and cooling to be converted into liquid, thereby completing the working fluid cycle.

[0201] Fig.18 FIG. 1 is a structural schematic diagram of a carbon dioxide capture system 10 according to an embodiment of the present invention.

[0202] In some embodiments, when one of the first heat pump type waste heat recovery and utilization component 15 and the third heat pump type waste heat recovery and utilization component 35 is set in the carbon dioxide capture system 10 to correspondingly recover and utilize one of the lean liquid waste heat and the absorption liquid reaction waste heat, the carbon dioxide capture system 10 may also include another waste heat recovery heat exchanger for recovering the other of the lean liquid waste heat and the absorption liquid reaction waste heat, and the working fluid inlet and working fluid outlet of the other waste heat recovery heat exchanger are connected to the working fluid loop of the waste heat recovery heat pump of the first heat pump type waste heat recovery and utilization component 15 or the third heat pump type waste heat recovery and utilization component 35 in parallel with the working fluid inlet and working fluid outlet of the waste heat recovery heat exchanger in the first heat pump type waste heat recovery and utilization component 15 or the third heat pump type waste heat recovery and utilization component 35.

[0203] For example, Fig.18As shown, in some embodiments, when the first heat pump type waste heat recovery and utilization component 15 is provided in the carbon dioxide capture system 10 but the third heat pump type waste heat recovery and utilization component 35 is not provided, the carbon dioxide capture system 10 may further include a third waste heat recovery heat exchanger 641, whose absorbent inlet 351a and absorbent outlet 351b are respectively connected to the absorbent outlet 113 and the absorbent return port 114 of the absorption tower 110, and whose working fluid inlet 351c and working fluid outlet 351d are connected to the working fluid loop of the first waste heat recovery heat pump 150 in parallel with the working fluid inlet and working fluid outlet of the first waste heat recovery heat exchanger 151, so that the first heat pump working fluid is divided into the first waste heat recovery heat exchanger 151 and the third waste heat recovery heat exchanger 641, and the first heat pump working fluid flowing out of the first waste heat recovery heat exchanger 151 and the third waste heat recovery heat exchanger 641 is combined and circulated. The third waste heat recovery heat exchanger 641 is configured to perform heat exchange between the absorbent drawn out from the absorption tower 110 and the first heat pump working fluid entering therein.

[0204] Those skilled in the art can understand that, similarly, when the third heat pump type waste heat recovery and utilization component 35 is provided in the carbon dioxide capture system 10 but the first heat pump type waste heat recovery and utilization component 15 is not provided, another waste heat recovery heat exchanger can also be provided between the lean liquid feed inlet 112 of the absorption tower 110 and the cold lean liquid outlet 124 of the lean-rich liquid heat exchanger 120, and the other waste heat recovery heat exchanger can be connected to the working fluid loop of the third waste heat recovery heat pump 350 in parallel with the fourth waste heat recovery heat exchanger 351.

[0205] Continue to see Fig.18 As shown, in some embodiments, the fourth heat pump type waste heat recovery and utilization component 45 may further include a third coupled heat exchanger 380. The third coupled heat exchanger 380 is connected to the working medium loop of the fourth waste heat recovery heat pump 450 and is located downstream of the fourth waste heat utilization device 460, and is connected to the pipeline between the second splitter 100 and the cold rich liquid inlet 121 of the lean-rich liquid heat exchanger 120, and is configured to make the working medium output from the fourth waste heat utilization device 450 and the rich liquid diverted from the second splitter 100 perform heat exchange therein, and output the rich liquid after heat exchange to the cold rich liquid inlet 121 of the lean-rich liquid heat exchanger 120.

[0206] Fig.23 It is a schematic structural diagram of each waste heat utilization device according to an embodiment of the utility model.

[0207] See also Fig.23As shown, in some optional embodiments, the first waste heat utilization device 160, the second waste heat utilization device 260, the third waste heat utilization device 360, the third waste heat utilization device 460, the regeneration gas waste heat utilization device 560 and / or the compressed regeneration gas waste heat utilization device 660 may each include a first reboiler 171. The first reboiler 171 is configured to heat-exchange the lean liquid drawn from the bottom of the desorption tower 130 with the working fluid after absorbing heat in the corresponding waste heat recovery heat pump to desorb carbon dioxide, and then return to the bottom of the desorption tower 130, and make the working fluid after heat exchange at least partially undergo phase change to liquid working fluid, and output the working fluid after heat exchange.

[0208] Specifically, the first reboiler 171 has a middle lean liquid inlet 171a, a middle lean liquid outlet 171b, a working fluid inlet 171c and a working fluid outlet 171d. A middle lean liquid outlet 134 and a middle lean liquid return port 135 are provided at the bottom of the desorption tower 130. The middle lean liquid inlet 171a and the middle lean liquid outlet 171b of the first reboiler 171 are respectively connected to the bottom of the desorption tower 130 to receive the middle lean liquid flowing in from the desorption tower 130 and to flow out the middle lean liquid to the desorption tower 130, respectively, and the working fluid inlet 171c and the working fluid outlet 171d are respectively connected to the working fluid loop where the first reboiler 171 is located to receive the working fluid flowing in and return the working fluid flowing out to the working fluid loop.

[0209] In this embodiment, the first reboiler 171 can be regarded as a condenser, and the carbon dioxide lean liquid drawn from the bottom of the desorption tower 13 is used as a condensing medium to exchange heat with the high-temperature compressed working fluid steam. The lean liquid directly absorbs the heat released by the compressed working fluid steam to desorb carbon dioxide, and the compressed working fluid steam is cooled and condensed. In this way, the reboiler and the working fluid condenser are combined into one, which simplifies the structure while efficiently utilizing the recovered waste heat, reduces the number of equipment, and reduces the system equipment cost.

[0210] Fig.24 It is a schematic structural diagram of each waste heat utilization device according to another embodiment of the utility model.

[0211] See also Fig.24As shown, in some other optional embodiments, the first waste heat utilization device 160, the second waste heat utilization device 260, the third waste heat utilization device 360, the third waste heat utilization device 460, the regeneration gas waste heat utilization device 560 and / or the compressed regeneration gas waste heat utilization device 660 may each include a second reboiler 172 and a condensing heat exchanger 174. The condensing heat exchanger 174 is connected to the working medium loop of the corresponding waste heat recovery heat pump where the waste heat utilization device is located, and is configured to make the condensed water entering the condensing heat exchanger 174 perform heat exchange with the compressed working medium steam to generate water vapor, and make the compressed working medium steam after heat exchange at least partially condense into liquid working medium, and output the working medium after heat exchange. The second reboiler 172 is connected to the bottom of the desorption tower 130 and the condensing heat exchanger 174 respectively, and is configured to allow the lean liquid drawn from the bottom of the desorption tower 130 to exchange heat with water vapor from the condensing heat exchanger 174 to desorb carbon dioxide, and then return to the bottom of the desorption tower 130, and condense the water vapor into water to output to the condensing heat exchanger 174.

[0212] Optionally, a water vapor compression device (not shown) may be provided between the second reboiler 172 and the condensing heat exchanger 174 to compress and heat the generated water vapor. The compressed and heated water vapor then enters the second reboiler 172 .

[0213] In this embodiment, by setting up a condensing heat exchanger 174, water is used as a condensing medium to exchange heat with the high-temperature compressed working fluid steam to generate water vapor, and then the water vapor is used to enter the second reboiler 172 to heat the lean liquid in the carbon dioxide drawn from the bottom of the desorption tower 13 to achieve carbon dioxide desorption. This method can not only efficiently utilize the recovered waste heat, but also directly utilize the original reboiler of the desorption tower without modifying the reboiler (such as selecting a material suitable for the working fluid) or changing the operating conditions and process of the reboiler, thereby reducing the modification cost of the system.

[0214] In some further embodiments, see Fig.24 As shown, the aforementioned first waste heat utilization device 160, the second waste heat utilization device 260, the third waste heat utilization device 360, the third waste heat utilization device 460, the regeneration gas waste heat utilization device 560 and / or the compressed regeneration gas waste heat utilization device 660 can each further include a flash evaporator 173 connected between the second reboiler 172 and the condensing heat exchanger 174. The second reboiler 172 has a middle lean liquid inlet 172a, a middle lean liquid outlet 172b, a water vapor inlet 172c and a condensed water outlet 172d. The flash evaporator 173 has a fluid inlet 173a, a liquid outlet 173b and a water vapor outlet 173c. The condensing heat exchanger 174 has a working fluid inlet 174a, a working fluid outlet 174b, a condensed water inlet 174c and a fluid outlet 174d.

[0215] The working medium inlet 174a and working medium outlet 174b of the condensing heat exchanger 174 are respectively connected to the working medium loop of the corresponding waste heat recovery heat pump where the waste heat utilization device is located, and the condensing heat exchanger 174 is configured to make the condensed water entering the condensing heat exchanger 174 and the compressed working medium steam flowing in exchange for heat to produce high-temperature fluid (high-temperature water, water vapor, or a mixture of the two), and make the compressed working medium steam after heat exchange at least partially condense into liquid working medium, and output the working medium after heat exchange through the working medium outlet 174b. The fluid inlet 173a of the flash evaporator 173 is connected to the fluid outlet 174d of the condensing heat exchanger 174, and the liquid outlet 173b is connected to the condensed water inlet 174c of the condensing heat exchanger 174, and the flash evaporator 173 is configured to flash the high-temperature fluid from the condensing heat exchanger 174 to produce water vapor and liquid water. The liquid water produced in the flash evaporator 173 is output to the condensing heat exchanger 174 through the liquid outlet 173b and the condensed water inlet 174c. The middle lean liquid inlet 172a, the middle lean liquid outlet 172b, the water vapor inlet 172c and the condensed water outlet 172d of the second reboiler 172 are respectively connected to the middle lean liquid outlet and the middle lean liquid return port at the bottom of the desorption tower 130, the water vapor outlet 173c of the flash evaporator 173 and the condensed water inlet 174c of the condensing heat exchanger 174, and the second reboiler 172 is configured to make the middle lean liquid drawn from the bottom of the desorption tower 130 heat exchange with the water vapor from the flash evaporator 173 to desorb carbon dioxide, and then return to the bottom of the desorption tower, while condensing the water vapor into condensed water and outputting it to the condensing heat exchanger 174.

[0216] Optionally, a water vapor compression device (not shown) may be provided between the second reboiler 172 and the flash evaporator 173 to compress and heat the generated water vapor. The compressed and heated water vapor then enters the second reboiler 172 .

[0217] In this embodiment, the flash evaporator 173 is used to flash evaporate the high-temperature fluid generated by the condensing heat exchanger 174, so as to further improve the quality of the generated water vapor, thereby further improving the utilization efficiency of the recovered waste heat.

[0218] In some embodiments of the present invention, an absorbent is also provided. The absorbent is a CO2 composite absorbent comprising a cyclic organic amine, a sterically hindered amine, a soluble metal salt and water. The CO2 composite absorbent can be applied to a carbon dioxide capture system 10 that uses a heat pump to recover waste heat without diverting the lean liquid output from the desorption tower 130.

[0219] In some embodiments, the total mass proportion of cyclic organic amines, sterically hindered amines and soluble metal salts in the composite absorbent may be 20-60%, for example, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%.

[0220] In some preferred embodiments, the total mass proportion of the cyclic organic amine, the sterically hindered amine and the soluble metal salt in the composite absorbent may be 30-45%.

[0221] In some specific embodiments, the CO2 composite absorbent comprises, by mass: 10-25% of a cyclic organic amine, 10-35% of a sterically hindered amine, 3-12% of a soluble metal salt and the remainder of water.

[0222] In some more specific embodiments, the mass proportion of the cyclic organic amine in the CO2 composite absorbent may be 10%, 12%, 15%, 18%, 20%, 22%, etc.

[0223] In some more specific embodiments, the mass proportion of the sterically hindered amine in the CO2 composite absorbent may be 12%, 15%, 18%, 20%, 22%, 25%, 27%, 30%, 33%, etc.

[0224] In some more specific embodiments, the mass proportion of the soluble metal salt in the CO2 composite absorbent may be 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, etc.

[0225] In some optional embodiments, the cyclic organic amine can be a mixture of one or more of piperazine, N-hydroxyethylpiperazine, 1-(2-hydroxyethyl)-4-aminopiperidine, 4-hydroxy-1-methylpiperidine, 3-aminomethylpyridine, and N-aminoethylpiperazine.

[0226] In some optional embodiments, the sterically hindered amine may be a mixture of one or more of 2-amino-2-methyl-1-propanol, isopropanolamine, sodium aminoisobutyrate, and 2-amino-2-ethyl-1,3-propanediol.

[0227] In some optional embodiments, the soluble metal salt may be a mixture of one or more of zinc sulfate, nickel sulfate, copper sulfate, cobalt sulfate, and manganese sulfate.

[0228] The compound absorbent of cyclic organic amine and sterically hindered amine has the advantages of high CO2 load, low CO2 reaction heat and low desorption energy consumption. The reason is that the cyclic organic amine contains a polyamine structure, and the concentration of amine groups per unit mole of molecule is significantly higher than that of monoethanolamine, which increases the CO2 absorption capacity; sterically hindered amine doubles its theoretical CO2 absorption capacity compared with primary ethanolamine by accepting reaction protons. Therefore, the compound absorbent increases the CO2 absorption per unit mass of solution, while reducing the CO2 reaction heat and heat energy consumption in the solvent regeneration process.

[0229] The inventors of the present application also studied the changes in the CO2 reaction heat before and after the metal ions were introduced into the organic amine absorbent. Fig.25 shown.

[0230] Depend on Fig.25 It can be seen that on the basis of the composite absorbent of cyclic organic amine and sterically hindered amine, the introduction of metal ions into the composite absorbent further reduces the CO2 reaction heat. This is because the metal ions form a metal organic amine complex with the composite absorbent, and the metal complex forms a chemical reaction heat buffer medium based on Le Chatelier dynamic equilibrium under the action of the CO2 acid effect. This buffer medium stores the reaction heat released during the absorption of CO2 by organic amine in the dissociation bond energy of the metal complex, and releases the stored energy for CO2 desorption through its complex exothermic reaction in CO2 desorption, thereby recovering the CO2 reaction heat. Taking the composite absorbent of 12% piperazine / 28% 2-amino-2-methyl-1-propanol / 5% nickel sulfate as an example, the reaction heat is reduced from 73kJ / molCO2 to 69kJ / molCO2, and the desorption energy consumption is reduced from 2.6GJ / tonCO2 to 2.4GJ / tonCO2. The desorption energy consumption is obtained by adding the reaction heat, sensible heat and latent heat. The sensible heat is obtained by ASPENPlus simulation under the condition of 5K of the lean and rich liquid heat exchanger, and the latent heat is calculated by ASPEN PLUS simulation under the condition of rich liquid diversion optimization.

[0231] At the same time, the Lewis acid properties of transition metal ions can change the pH of the organic amine system, promote the transformation of carbamate to bicarbonate, and reduce the desorption temperature while reducing the CO2 reaction heat. Taking the 12% piperazine / 28% 2-amino-2-methyl-1-propanol / 5% nickel sulfate composite absorbent as an example, the desorption temperature is reduced from 117°C to 112°C under 2bar conditions. The reduction in desorption temperature helps to reduce the temperature difference between the cold and hot ends of the heat pump process. Taking R245fa as an example, the COP performance is improved from 2.2 to 2.4, which improves the heat pump efficiency and carbon capture energy utilization efficiency.

[0232] In the description provided herein, a large number of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

[0233] At this point, those skilled in the art should recognize that, although multiple exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications that conform to the principles of the present invention can still be directly determined or derived from the contents disclosed in the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and recognized as covering all such other variations or modifications.

Claims

1. A heat pump waste heat regeneration module for a carbon dioxide capture system, comprising: A desorption tower having a regeneration gas outlet, a gas-liquid separator connected to the regeneration gas outlet of the desorption tower through a pipeline, and a regeneration gas compression device connected to the gas outlet of the gas-liquid separator; characterized in that the heat pump type waste heat regeneration module also includes: The fourth heat pump waste heat recovery and utilization component includes: a fourth waste heat recovery heat pump, comprising a sixth waste heat recovery heat exchanger arranged in a pipeline between the regeneration gas outlet of the desorption tower and the gas-liquid separator and a seventh waste heat recovery heat exchanger connected to the regeneration gas compression device, the sixth waste heat recovery heat exchanger being configured to allow the heat pump working fluid flowing therethrough to exchange heat with the regeneration gas output from the regeneration gas outlet in the sixth waste heat recovery heat exchanger to recover the waste heat of the regeneration gas, and the seventh waste heat recovery heat exchanger being configured to allow the heat pump working fluid flowing therethrough to exchange heat with the compressed regeneration gas generated by the regeneration gas compression device in the seventh waste heat recovery heat exchanger to recover the waste heat of the compressed regeneration gas; and The fourth waste heat utilization device is correspondingly connected to the working fluid loop of the fourth waste heat recovery heat pump and is connected to the bottom of the desorption tower. It is configured to utilize the recovered regeneration gas waste heat and the compressed regeneration gas waste heat to heat the lean liquid at the bottom of the desorption tower through heat exchange to desorb carbon dioxide.

2. The heat pump waste heat regeneration module according to claim 1, characterized in that: The heat pump working fluid flowing through the sixth waste heat recovery heat exchanger and the seventh waste heat recovery heat exchanger is the same sixth heat pump working fluid; The fourth waste heat recovery heat pump is a single-stage compression heat pump, which includes the seventh waste heat recovery heat exchanger, the sixth waste heat recovery heat exchanger, the sixth working medium compressor and the sixth throttle valve which are sequentially connected through pipelines to form a sixth working medium loop for circulating the working medium of the sixth heat pump, and the fourth waste heat utilization device is connected in the pipeline between the sixth working medium compressor and the sixth throttle valve; The sixth working fluid loop is configured to allow the sixth heat pump working fluid flowing out of the sixth throttle valve to flow into the seventh waste heat recovery heat exchanger and the sixth waste heat recovery heat exchanger in liquid state in sequence to undergo phase change and be converted into steam after heat exchange with the compressed regeneration gas and the regeneration gas respectively, and then enter the sixth waste heat utilization device after being compressed by the sixth working fluid compressor to heat the lean liquid at the bottom of the desorption tower, and then pass through the sixth throttle valve for throttling and cooling to be converted into liquid state, thereby completing the working fluid cycle.

3. The heat pump waste heat regeneration module according to claim 1, characterized in that: The heat pump working fluid flowing through the sixth waste heat recovery heat exchanger and the seventh waste heat recovery heat exchanger is the same sixth heat pump working fluid; The fourth waste heat recovery heat pump is a single-stage compression heat pump, comprising the seventh waste heat recovery heat exchanger, the sixth waste heat recovery heat exchanger, a sixth working fluid compressor and a sixth throttle valve, wherein the seventh waste heat recovery heat exchanger and the sixth waste heat recovery heat exchanger are connected in parallel and then sequentially connected to the sixth working fluid compressor and the sixth throttle valve through a pipeline to form a sixth working fluid loop for circulating the working fluid of the sixth heat pump, and the fourth waste heat utilization device is connected to the pipeline between the sixth working fluid compressor and the sixth throttle valve; The sixth working fluid loop is configured to allow the sixth heat pump working fluid flowing out of the sixth throttle valve to be diverted in a liquid state into the seventh waste heat recovery heat exchanger and the sixth waste heat recovery heat exchanger to undergo a phase change and be converted into steam after heat exchange with the compressed regeneration gas and the regeneration gas respectively, and then enter the sixth waste heat utilization device to heat the lean liquid at the bottom of the desorption tower after being compressed by the sixth working fluid compressor, and then pass through the sixth throttle valve for throttling and cooling to be converted into a liquid state, thereby completing the working fluid cycle.

4. The heat pump waste heat regeneration module according to claim 1, characterized in that: The fourth waste heat recovery heat pump includes a mutually independent regeneration gas waste heat recovery heat pump unit and a compressed regeneration gas waste heat recovery heat pump unit, wherein the regeneration gas waste heat recovery heat pump unit includes the sixth waste heat recovery heat exchanger to recover the waste heat of the regeneration gas, and the compressed regeneration gas waste heat recovery heat pump unit includes the seventh waste heat recovery heat exchanger to recover the waste heat of the compressed regeneration gas; The fourth waste heat utilization device includes a mutually independent regeneration gas waste heat utilization device and a compressed regeneration gas waste heat utilization device, wherein the regeneration gas waste heat utilization device is connected to the working fluid loop of the regeneration gas waste heat recovery heat pump unit and is connected to the bottom of the desorption tower, and is configured to utilize the recovered regeneration gas waste heat to heat the middle-lean liquid at the bottom of the desorption tower through heat exchange to desorb carbon dioxide; the compressed regeneration gas waste heat utilization device is connected to the working fluid loop of the compressed regeneration gas waste heat recovery heat pump unit and is connected to the bottom of the desorption tower, and is configured to utilize the recovered compressed regeneration gas waste heat to heat the middle-lean liquid at the bottom of the desorption tower through heat exchange to desorb carbon dioxide.

5. The heat pump waste heat regeneration module according to claim 4, characterized in that: The regeneration gas waste heat recovery heat pump unit is a single-stage compression heat pump, comprising the sixth waste heat recovery heat exchanger, the seventh working fluid compressor and the seventh throttle valve which are sequentially connected through pipelines to form a seventh working fluid loop for circulating the seventh heat pump working fluid, and the regeneration gas waste heat utilization device is connected to the pipeline between the seventh working fluid compressor and the seventh throttle valve; The seventh working fluid loop is configured to allow the seventh heat pump working fluid to flow into the sixth waste heat recovery heat exchanger in a liquid state, undergo a phase change and be converted into steam after exchanging heat with the regenerated gas, and then enter the regenerated gas waste heat utilization device after being compressed by the seventh working fluid compressor to heat the lean liquid at the bottom of the desorption tower, and then pass through the seventh throttle valve for throttling and cooling to be converted into a liquid state, and then flow into the sixth waste heat recovery heat exchanger.

6. The heat pump waste heat regeneration module according to claim 4, characterized in that: The compressed regeneration gas waste heat recovery heat pump unit is a single-stage compression heat pump, comprising the seventh waste heat recovery heat exchanger, the eighth working medium compressor and the eighth throttle valve which are sequentially connected through pipelines to form an eighth working medium loop for circulating the eighth heat pump working medium, and the compressed regeneration gas waste heat utilization device is connected to the pipeline between the eighth working medium compressor and the eighth throttle valve; The eighth working fluid loop is configured to allow the eighth heat pump working fluid to flow into the seventh waste heat recovery heat exchanger in a liquid state, undergo a phase change and be converted into steam after heat exchange with the compressed regeneration gas, be compressed by the eighth working fluid compressor and enter the compressed regeneration gas waste heat utilization device to heat the lean liquid at the bottom of the desorption tower, then pass through the eighth throttle valve for throttling and cooling to be converted into a liquid state, and then flow into the seventh waste heat recovery heat exchanger.

7. The heat pump waste heat regeneration module according to any one of claims 1 to 6, characterized in that: The regeneration gas compression device comprises a multi-stage sub-compressor, and the multi-stage sub-compressors are connected in series in sequence to form a step-by-step compression structure; The seventh waste heat recovery heat exchanger includes a plurality of interstage heat exchangers in parallel, and the plurality of interstage heat exchangers and the multi-stage sub-compressors are arranged at intervals along the flow direction of the compressed regeneration gas, wherein each interstage heat exchanger except the last interstage heat exchanger arranged along the flow direction of the compressed regeneration gas is arranged between the outlet of the previous stage sub-compressor and the inlet of the next stage sub-compressor, and the compressed gas inlet of the last interstage heat exchanger is connected to the compressed gas outlet of the last stage sub-compressor.

8. The heat pump waste heat regeneration module according to any one of claims 1 to 6, characterized in that: The regeneration gas compression device comprises a multi-stage sub-compressor, and the multi-stage sub-compressors are connected in series in sequence to form a step-by-step compression structure; The seventh waste heat recovery heat exchanger includes a plurality of interstage heat exchangers connected in series, and the plurality of interstage heat exchangers and the multi-stage sub-compressors are arranged at intervals along the flow direction of the compressed regeneration gas, wherein each interstage heat exchanger except the last interstage heat exchanger arranged along the flow direction of the compressed regeneration gas is arranged between the outlet of the previous stage sub-compressor and the inlet of the next stage sub-compressor, and the compressed gas inlet of the last interstage heat exchanger is connected to the compressed gas outlet of the last stage sub-compressor.

9. The heat pump waste heat regeneration module according to any one of claims 1 to 6, characterized in that: Each waste heat utilization device includes a first reboiler, which is configured to heat-exchange the medium-lean liquid drawn from the bottom of the desorption tower with the working fluid after absorbing heat in the corresponding waste heat recovery heat pump to desorb carbon dioxide, and then return to the bottom of the desorption tower, and make the working fluid after heat exchange at least partially undergo phase change to liquid working fluid, and output the working fluid after heat exchange; or Each waste heat utilization device includes a second reboiler connected to the bottom of the desorption tower, a condensing heat exchanger connected to the working fluid loop of the corresponding waste heat recovery heat pump, and a flash evaporator connected between the second reboiler and the condensing heat exchanger, wherein the condensing heat exchanger is configured to allow water entering the condensing heat exchanger to perform heat exchange with the working fluid after absorbing heat in the corresponding waste heat recovery heat pump to produce a high-temperature fluid, and to cause the working fluid after the heat exchange to at least partially condense into a liquid working fluid, and output the working fluid after the heat exchange; the flash evaporator is configured to flash the high-temperature fluid from the condensing heat exchanger to produce water vapor and liquid water, and output the water vapor and liquid water to the second reboiler and the condensing heat exchanger respectively; the second reboiler is configured to allow the lean liquid drawn from the bottom of the desorption tower to perform heat exchange with the water vapor from the flash evaporator to desorb carbon dioxide, and then return to the bottom of the desorption tower, and at the same time, the water vapor is condensed into condensed water and then output to the condensing heat exchanger.

10. A carbon dioxide capture system comprising: Absorption tower and lean-rich liquid heat exchanger; characterized in that the carbon dioxide capture system also includes a heat pump type waste heat regeneration module according to any one of claims 1 to 9, wherein the cold rich liquid inlet, hot rich liquid outlet, hot lean liquid inlet and cold lean liquid outlet of the lean-rich liquid heat exchanger are respectively connected to the rich liquid outlet of the absorption tower, the first rich liquid feed inlet of the desorption tower, the hot lean liquid outlet of the desorption tower and the lean liquid feed inlet of the absorption tower through pipelines.

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