Carbon dioxide capture coupled with waste heat recovery system

Abstract

The application discloses a carbon dioxide capturing and waste heat recycling system, which comprises a capturing assembly and a heat exchanging assembly. The capturing assembly comprises an absorption tower, a regeneration tower and a drying tower. A lean-rich liquid heat exchanger is arranged between the absorption tower and the regeneration tower. A part of rich liquid is heat exchanged with lean liquid through the lean-rich liquid heat exchanger. The flow of the rich liquid and the flow of the lean liquid through the lean-rich liquid heat exchanger are matched, so that the rich liquid reaches the expected temperature rising effect. A reboiler is arranged at the bottom of the regeneration tower. The reboiler heats the rich liquid by using steam to generate regeneration gas. The regeneration gas is dried by using a drying agent in the drying tower, and the drying agent can be heated and regenerated. The heat exchanging assembly is connected with the absorption tower, the regeneration tower and the drying tower. Another part of the rich liquid is preheated by using the waste heat of the water vapor generated by the used steam, the regeneration gas and / or the drying agent. The energy utilization rate is improved, the energy consumption is reduced, and the rich liquid reaches the expected temperature rising effect.

Description

Technical Field

[0001] This invention relates to the field of flue gas purification technology, and in particular to a carbon dioxide capture coupled with waste heat recovery system. Background Technology

[0002] Carbon dioxide, a major greenhouse gas produced by burning fossil fuels, contributes to global warming. Some power plants reduce carbon dioxide emissions and protect the environment by installing carbon capture systems after the boilers to capture carbon dioxide from the flue gas.

[0003] The carbon capture system includes an absorption tower and a regeneration tower. Flue gas passes through the absorption tower and carbon dioxide is captured by an absorbent. The absorbent that captures carbon dioxide is heated and desorbed in the regeneration tower. The desorbed carbon dioxide is compressed and stored or converted into valuable industrial raw materials.

[0004] In this process, the absorbent flowing out of the absorption tower after capturing carbon dioxide is a low-temperature rich solution, while the absorbent flowing out of the regeneration tower after heating and desorption is a high-temperature lean solution. Related technologies include installing a lean-rich solution heat exchanger between the absorption tower and the regeneration tower to achieve heat exchange between the low-temperature rich solution and the high-temperature lean solution. This preheats the low-temperature rich solution and precools the high-temperature lean solution, improving energy utilization and reducing energy consumption.

[0005] However, the mismatch between the flow rates of the low-temperature rich solution and the high-temperature lean solution resulted in limited heating of the low-temperature rich solution, failing to achieve the expected heating effect. Summary of the Invention

[0006] This invention is based on the inventor's discoveries and understanding of the following facts and problems:

[0007] In related technologies, the absorbent is an organic amine solution, and water is used as the solvent. During the heating and desorption process of the rich liquid in the regeneration tower, the desorbed carbon dioxide carries water vapor out of the regeneration tower, resulting in the loss of the regenerated lean liquid. The amount of lean liquid is lower than that of rich liquid, which leads to a mismatch between the flow rates of lean and rich liquids in the lean-rich liquid heat exchanger, and the rich liquid cannot achieve the expected heating effect.

[0008] Furthermore, a reboiler is installed at the bottom of the regeneration tower. Steam from the power generation system is drawn into the reboiler as a heat source to heat and regenerate the absorbent. The used steam flows back into the power generation system. The regenerated gas exiting the regeneration tower is subsequently dehydrated and compressed, and finally the compressed carbon dioxide is stored. Specifically, the regenerated gas is first condensed and separated from moisture by a cooler and separator, and then passes through a drying tower where moisture is removed using a desiccant. The saturated desiccant can be heated for regeneration.

[0009] However, the heat in the steam after use in the reboiler, the heat in the regenerated gas flowing out of the regeneration tower, and the heat in the water vapor heated by the desiccant are not fully utilized, and there is a problem of energy waste.

[0010] The present application aims to at least partially solve one of the technical problems in the related art.

[0011] To this end, an embodiment of the present application proposes a carbon dioxide capture coupled waste heat recycling system, which has the characteristics of reasonable matching of energy utilization and high energy utilization rate.

[0012] The carbon dioxide capture coupled waste heat recycling system of the embodiment of the present application comprises:

[0013] A capture assembly, comprising an absorption tower, a regeneration tower and a drying tower connected in sequence, a lean-rich liquid heat exchanger is arranged between the absorption tower and the regeneration tower, a part of rich liquid flowing out of the absorption tower exchanges heat with lean liquid flowing out of the regeneration tower through the lean-rich liquid heat exchanger, and the flow rate of the rich liquid and the flow rate of the lean liquid passing through the lean-rich liquid heat exchanger are matched, a reboiler is arranged at the bottom of the regeneration tower, the reboiler is used to heat the rich liquid flowing into the regeneration tower by using steam as a heat source, the drying tower has a drying mode and a regeneration mode, in the drying mode, the drying tower is used to adsorb moisture in the regeneration gas generated by heating the rich liquid in the regeneration tower by using a desiccant, and in the regeneration mode, the drying tower is used to heat the desiccant after regeneration and adsorption saturation;

[0014] A heat exchange assembly connected with the absorption tower, the regeneration tower, the reboiler and the drying tower, the heat exchange assembly is used to use the steam after heating the regenerated rich liquid of the reboiler, the regeneration gas generated by heating the rich liquid of the regeneration tower and / or the water vapor generated by heating the regenerated desiccant of the drying tower as a heat source to preheat another part of the rich liquid flowing out of the absorption tower.

[0015] The carbon dioxide capture coupled waste heat recycling system of the embodiment of the present application divides the rich liquid flowing out of the absorption tower into two parts. One part of the rich liquid is preheated by using lean liquid, and the flow rate of this part of the rich liquid is matched with the flow rate of the lean liquid to ensure the expected temperature rise effect. The remaining part of the rich liquid is preheated by using the waste heat of the capture and regeneration process, which fully utilizes the waste heat of the capture and regeneration process, not only improves the energy utilization rate and reduces the energy consumption, but also ensures that the rich liquid reaches the expected temperature rise effect.

[0016] In some embodiments, the carbon dioxide capture system further comprises a power generation assembly, the power generation assembly comprising a boiler and a steam turbine assembly connected in series, the steam turbine assembly connected to the reboiler to extract steam from the steam turbine assembly as a heat source for the reboiler, the heat exchange assembly comprising a first heat exchanger connected to the absorber, the regenerator, the reboiler and the boiler to preheat the rich solution from the absorber with the steam from the reboiler after heating the regenerated rich solution in the first heat exchanger, and the rich solution preheated in the first heat exchanger flows into the regenerator together with the rich solution exchanged in the lean-rich solution heat exchanger.

[0017] In some embodiments, a first water cooler is provided between the first heat exchanger and the boiler to condense the steam from the first heat exchanger after preheating the rich solution in the first water cooler and return the condensed steam to the boiler.

[0018] In some embodiments, the heat exchange assembly further comprises a second heat exchanger connected to the absorber and the regenerator to preheat the rich solution from the absorber with the regenerator gas from the regenerator in the second heat exchanger, and the rich solution preheated in the second heat exchanger flows into the regenerator together with the rich solution exchanged in the lean-rich solution heat exchanger.

[0019] In some embodiments, the capture assembly further comprises a second water cooler, a regenerator gas separator and a centrifugal compressor assembly connected in series, the second water cooler connected to the second heat exchanger to condense the regenerator gas from the second heat exchanger after preheating the rich solution in the second water cooler and flow into the regenerator gas separator, the gaseous phase medium separated from the regenerator gas separator is carbon dioxide gas, and the carbon dioxide gas is compressed from gas phase to liquid phase in the centrifugal compressor assembly, the centrifugal compressor assembly connected to the drying tower to flow into the drying tower after drying with the drying agent and flow back to the centrifugal compressor assembly.

[0020] In some embodiments, the drying tower has a plurality of drying towers, at least one of the drying towers operates in the drying mode, and at least one of the drying towers operates in the regeneration mode.

[0021] The drying tower operates in the drying mode, the carbon dioxide gas flowing into the drying tower is dried with the drying agent and flows back to the centrifugal compressor assembly.

[0022] The drying tower operates in the regeneration mode, the carbon dioxide gas flowing into the drying tower is used as a heating medium for the regeneration of the drying agent.

[0023] In some embodiments, the trapping assembly further comprises an electric heater connected to the drying tower, the carbon dioxide gas stream in the drying tower operating in the regeneration mode flows to the electric heater for heating, the heated carbon dioxide gas stream flows back into the drying tower to heat the regenerating desiccant and generate water vapor, to generate a mixed gas of carbon dioxide gas and water vapor.

[0024] In some embodiments, the heat exchanging assembly further comprises a third heat exchanger connected to the absorption tower, the regeneration tower and the drying tower, to preheat the rich liquid flowing out of the absorption tower with the mixed gas of the drying tower in the third heat exchanger, and the preheated rich liquid through the third heat exchanger flows into the regeneration tower together with the rich liquid exchanged by the lean-rich liquid heat exchanger.

[0025] In some embodiments, the trapping assembly further comprises a third water cooler and a dry gas separator connected in sequence, the third water cooler is connected to the third heat exchanger, to condense the mixed gas after preheating the rich liquid in the third heat exchanger through the third water cooler, and the dry gas separator is connected to the drying tower, to make the gaseous phase medium separated by the dry gas separator flow back to the centrifugal compressor set after drying in the drying tower operating in the drying mode.

[0026] In some embodiments, the centrifugal compressor set comprises multiple centrifugal compressors connected in sequence, the inlet of the drying tower is connected to the centrifugal compressor at the upper level through a pipeline, and the outlet of the drying tower is connected to the centrifugal compressor at the lower level through a pipeline. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is a schematic diagram of a carbon dioxide trapping system coupled with waste heat reuse according to an embodiment of the present application.

[0028] REFERENCE NUMERALS

[0029] Absorption tower 1, regeneration tower 2, lean-rich liquid heat exchanger 3, reboiler 4, drying tower 5, boiler 6, steam turbine set 7, first heat exchanger 8, first water cooler 9, second heat exchanger 10, second water cooler 11, regeneration gas separator 12, centrifugal compressor set 13, electric heater 14, third heat exchanger 15, third water cooler 16, dry gas separator 17. DETAILED DESCRIPTION

[0030] The embodiments of the present application are described in detail below with reference to the accompanying drawings. The embodiments described below are exemplary and are intended to explain the present application, and should not be understood as limiting the present application.

[0031] The carbon dioxide capture coupled waste heat recovery system of the present invention is described below with reference to the accompanying drawings.

[0032] like Figure 1 As shown, the carbon dioxide capture coupled waste heat recovery system of this embodiment includes: a capture component and a heat exchange component.

[0033] The collection assembly includes an absorption tower 1, a regeneration tower 2, and a drying tower 5 connected in sequence. The absorption tower 1 is used to collect carbon dioxide from the flue gas after desulfurization and denitrification using an absorbent (organic amine solution). The regeneration tower 2 is used to desorb the carbon dioxide collected in the absorbent. The drying tower 5 is used to dry and dehydrate the desorbed carbon dioxide.

[0034] A lean-rich liquid heat exchanger 3 is installed between the absorption tower 1 and the regeneration tower 2. A portion of the rich liquid flowing out of the absorption tower 1 exchanges heat with the lean liquid flowing out of the regeneration tower 2 through the lean-rich liquid heat exchanger 3. The flow rates of the rich liquid and the lean liquid through the lean-rich liquid heat exchanger 3 are matched to ensure that the rich liquid achieves the expected heating effect, avoiding the problem in related technologies where the flow rates of the lean liquid and rich liquid are mismatched, resulting in the rich liquid failing to achieve the expected heating effect. Another portion of the rich liquid is preheated by other means to ensure that all the rich liquid flowing out of the absorption tower 1 is preheated before flowing into the regeneration tower 2 for heating and regeneration.

[0035] In other words, the problem of related technologies failing to achieve the expected heating effect is due to the flow rate of the rich solution being greater than that of the lean solution. The carbon dioxide capture coupled with waste heat recovery system of this invention extracts a portion of the rich solution for preheating using other methods, thereby reducing the flow rate of the rich solution exchanging heat with the lean solution. This allows the flow rate of the remaining rich solution to match the flow rate of the lean solution, thus achieving the expected heating effect.

[0036] A reboiler 4 is installed at the bottom of the regeneration tower 2. Steam is drawn from the power plant's generator system as a heat source. The absorbent in the regeneration tower 2 flows into the reboiler 4 and is regenerated by heating with steam. The generated regeneration gas includes carbon dioxide and water, both of which are in a gaseous state. After heat exchange between the steam and the absorbent in the reboiler 4, the temperature of the steam decreases. Therefore, the remaining heat in the cooled steam and the heat in the regeneration gas can be used to preheat the portion of the rich liquid flowing out of the absorber tower 1 that exceeds the lean liquid flow rate.

[0037] Furthermore, the drying tower 5 has a drying mode and a regeneration mode. When the drying tower 5 is in drying mode, the regeneration gas flows into the drying tower 5 and the desiccant adsorbs the moisture in the regeneration gas. After the desiccant is saturated, the drying tower 5 operates in regeneration mode, heating and regenerating the saturated desiccant. The regeneration product is water vapor, and the heat in the water vapor can also be used to preheat the portion of the rich liquid flowing out of the absorption tower 1 that exceeds the lean liquid flow rate.

[0038] Thus, the heat exchange assembly is connected with the absorption tower 1, the regeneration tower 2, the reboiler 4 and the drying tower 5. The steam cooled by the reboiler 4, the regenerated gas flowing out of the regeneration tower 2 and the water vapor flowing out of the drying tower 5 are transported to the heat exchange assembly, and the part of the rich liquid flowing out of the absorption tower 1 exceeding the lean liquid flow is also transported to the heat exchange assembly, so that the rich liquid is preheated by the waste heat in the carbon capture and regeneration process, which not only improves the energy utilization rate and reduces the energy consumption, but also achieves the expected warming effect.

[0039] In addition, the amount of carbon dioxide loaded by the absorbent determines the difference between the lean liquid flow and the rich liquid flow. The more the amount of carbon dioxide that the absorbent can load, the greater the difference between the rich liquid flow and the lean liquid flow, that is, the more the amount of the rich liquid that needs to be additionally extracted and preheated by other means. Conversely, the less the amount of carbon dioxide that the absorbent can load, the closer the rich liquid flow and the lean liquid flow.

[0040] The carbon dioxide capture and waste heat recycling system of the embodiment of the present application has multiple heat sources for preheating the rich liquid, so that the amount of the extracted rich liquid can be increased, so that the absorbent can load more carbon dioxide, thereby improving the carbon dioxide capture efficiency.

[0041] Optionally, as shown in Figure 1 The carbon dioxide capture and waste heat recycling system of the embodiment of the present application further includes a power generation assembly. The power generation assembly includes a boiler 6 and a steam turbine unit 7, the boiler 6 is connected with the steam turbine unit 7, and the boiler 6 sends steam into the steam turbine unit 7 to do work. The steam turbine unit 7 includes a high-pressure cylinder, a medium-pressure cylinder and a low-pressure cylinder connected in sequence, wherein the medium-pressure cylinder is connected with the reboiler 4 to extract steam from the medium-pressure cylinder as a heat source of the reboiler 4.

[0042] It can be understood that the advantage of extracting steam from the medium-pressure cylinder is balance and stability. The steam temperature of the high-pressure cylinder is too high, and the main function of the high-pressure cylinder is to use the expansion of high-pressure steam to do work, so that extracting steam from the high-pressure cylinder will affect the power generation effect. The steam grade of the low-pressure cylinder is low, and the effect of passing into the reboiler 4 to heat the regenerated absorbent is poor.

[0043] The heat exchange assembly includes a first heat exchanger 8, and the first heat exchanger 8 is connected with the absorption tower 1, the regeneration tower 2, the reboiler 4 and the boiler 6. The steam cooled by the reboiler 4 and exchanged with the absorbent is transported to the first heat exchanger 8, and a part of the rich liquid flowing out of the absorption tower 1 is also transported to the first heat exchanger 8, and the rich liquid is preheated by the waste heat in the cooled steam.

[0044] Moreover, the preheating effect of the cooled steam on the rich liquid and the preheating effect of the lean liquid on the rich liquid are substantially the same, so that the rich liquid preheated by the first heat exchanger 8 and the rich liquid heat-exchanged by the lean-rich liquid heat exchanger 3 are mixed with each other, and flow into the regeneration tower 2 together.

[0045] A first water cooler 9 is arranged between the first heat exchanger 8 and the boiler 6, so that the steam after being preheated by the first heat exchanger 8 flows into the first water cooler 9 to be condensed into water, and then returns to the boiler 6. The cooling source of the first water cooler 9 is the cooling water delivered by the water cooling tower of the power plant.

[0046] Thus, the first heat exchanger 8 is used to recycle the waste heat in the steam after being cooled by the reboiler 4, so as to improve the energy utilization rate and reduce the energy consumption of the system during the carbon capture and regeneration process.

[0047] In some embodiments, as shown in Figure 1 The heat exchange assembly further includes a second heat exchanger 10 connected with the absorption tower 1 and the regeneration tower 2. The regeneration gas generated by heating the rich solution in the regeneration tower 2 is delivered into the second heat exchanger 10, and a part of the rich solution flowing out of the absorption tower 1 is also delivered into the second heat exchanger 10. The rich solution is preheated by the heat in the regeneration gas, so as to recycle the waste heat of the regeneration gas and improve the energy utilization rate.

[0048] In addition, the preheating effect of the rich solution by the regeneration gas and the preheating effect of the rich solution by the lean solution are basically the same. The rich solution preheated by the second heat exchanger 10 and the rich solution exchanged by the lean-rich solution heat exchanger 3 are mixed with each other and then flow into the regeneration tower 2.

[0049] Optionally, as shown in Figure 1 The capture assembly further includes a second water cooler 11, a regeneration gas separator 12 and a centrifugal compressor set 13 connected in sequence.

[0050] The second water cooler 11 is connected with the second heat exchanger 10. The regeneration gas flowing out of the regeneration tower 2 is cooled by the second heat exchanger 10 and then flows into the second water cooler 11. The cooling source of the second water cooler 11 is the cooling water delivered by the water cooling tower of the power plant, which is used to condense the water in the regeneration gas.

[0051] The condensed regeneration gas flows into the regeneration gas separator 12 for separation. The separated liquid phase medium is weak alkaline water, which is returned to the water circulation pipeline of the carbon capture system. The separated gas phase medium is carbon dioxide gas, which is compressed from gas to liquid in the centrifugal compressor set 13. The finally produced liquid carbon dioxide is delivered to the underground storage or used to prepare industrial products through a pipeline.

[0052] The centrifugal compressor set 13 is connected with the drying tower 5, so that the preliminarily pressurized carbon dioxide gas flows into the drying tower 5 to be dried and then flows back to the centrifugal compressor set 13. After being preliminarily pressurized, the carbon dioxide gas is helpful to capture and remove the water therein.

[0053] For example, centrifugal compressor unit 13 includes a multi-stage centrifugal compressor connected sequentially via pipelines. The multi-stage centrifugal compressors are defined sequentially from upstream to downstream of the gas flow as a first-stage centrifugal compressor, an intermediate-stage centrifugal compressor, and a final-stage centrifugal compressor. The first-stage centrifugal compressor is connected to a regenerator gas separator 12, so that the carbon dioxide separated by the regenerator gas separator 12 flows to the first-stage and intermediate-stage centrifugal compressors for compression. The intermediate-stage centrifugal compressor is connected to the inlet of a drying tower 5 to draw the pre-compressed carbon dioxide into the drying tower 5 for drying. The final-stage centrifugal compressor is connected to the outlet of the drying tower 5, so that the dried carbon dioxide flows back to the final-stage centrifugal compressor for compression to a liquid state.

[0054] In some embodiments, such as Figure 1 As shown, there are multiple drying towers 5, which are arranged in parallel. At least one drying tower 5 operates in drying mode, and at least one drying tower 5 operates in regeneration mode.

[0055] Understandably, when the desiccant in drying tower 5, which is currently in drying mode, becomes saturated, the process will switch from carbon dioxide gas to drying tower 5 after the desiccant heating and regeneration is complete. This ensures the continuity of the carbon dioxide gas drying process and improves drying efficiency.

[0056] When the drying tower 5 is in drying mode, the carbon dioxide gas extracted from the centrifugal compressor unit 13 flows into the drying tower 5, is dried by the desiccant, and then flows back to the centrifugal compressor unit 13 for compression.

[0057] When the drying tower 5 is in regeneration mode, the carbon dioxide gas extracted from the centrifugal compressor unit 13 is first heated before flowing into the drying tower 5 as the heating medium for desiccant regeneration. After the desiccant regeneration is complete, the carbon dioxide gas is dried and then flows back to the centrifugal compressor unit 13.

[0058] Therefore, by making full use of the system's own products, there is no need to introduce external heating media, avoiding the need to modify the tower and increase economic costs.

[0059] Optionally, such as Figure 1 As shown, the trapping assembly also includes an electric heater 14, which is connected to the drying tower 5. When the drying tower 5 operates in regeneration mode, carbon dioxide gas extracted from the centrifugal compressor unit 13 flows to the electric heater 14 for heating. The heated carbon dioxide gas then flows back into the drying tower 5 to regenerate the desiccant. The product of the desiccant's regeneration is water vapor, producing a mixture of carbon dioxide gas and water vapor.

[0060] The heat exchange assembly further comprises a third heat exchanger 15 connected with the absorption tower 1, the regeneration tower 2 and the drying tower 5. The mixed gas generated by heating the desiccant in the drying tower 5 for regeneration is transported into the third heat exchanger 15, and a part of the rich liquid flowing out of the absorption tower 1 is also transported into the third heat exchanger 15, and the rich liquid is preheated by using the heat of the mixed gas, so that the waste heat of the mixed gas is reused, and the energy utilization rate is improved.

[0061] In addition, the preheating effect of the mixed gas on the rich liquid and the preheating effect of the lean liquid on the rich liquid are basically the same, so that the rich liquid preheated by the third heat exchanger 15 and the rich liquid heat-exchanged by the lean-rich liquid heat exchanger 3 are mixed with each other and flow into the regeneration tower 2 together.

[0062] The trapping assembly further comprises a third water cooler 16 and a dry gas separator 17 connected with each other, and the cooling source of the third water cooler 16 comes from the cooling water transported by the water cooling tower of the power plant. The third water cooler 16 is connected with the third heat exchanger 15, so that the mixed gas cooled by the third heat exchanger 15 flows into the third water cooler 16, and the water vapor in the mixed gas is condensed by using the cooling water.

[0063] The condensed mixed gas flows into the dry gas separator 17 for separation, and the condensed water separated out is directly discharged to the waste water treatment system of the power plant or used for coal plant spraying or used for ash, and the carbon dioxide gas separated out flows back to the centrifugal compressor set 13 for compression after being dried in the drying tower 5 in the drying mode.

[0064] The carbon dioxide trapping and waste heat reuse system of the embodiment of the present application reasonably utilizes the structure of the plurality of drying towers 5, and a part of the carbon dioxide gas preliminarily pressurized is sent into the drying tower 5 in the drying mode for direct drying treatment. Another part is sent into the drying tower 5 in the regeneration mode, heated by using the electric heater 14, and then used for the heating regeneration process of the saturated desiccant. After the desiccant is regenerated, the mixed gas is condensed and separated, and the separated carbon dioxide gas is sent into the drying tower 5 in the drying mode for drying treatment. Therefore, not only the continuity of carbon dioxide drying is ensured, the drying efficiency is improved, but also the collaborative ability of the system is highlighted, and the value of the system itself is improved.

[0065] In the description of the application, it is to be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the application and simplifying the description, and do not indicate or imply that the devices or elements indicated thereby must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the application.

[0066] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated thereby. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise explicitly specified and limited.

[0067] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected or in communication with each other; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication or interaction relationship of two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0068] In the present application, unless otherwise explicitly specified and limited, the first feature "on" or "under" the second feature can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be that the first feature is directly above or obliquely above the second feature, or it can only mean that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature can be that the first feature is directly below or obliquely below the second feature, or it can only mean that the horizontal height of the first feature is less than that of the second feature.

[0069] In this disclosure, the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" mean that a particular feature, structure, material, or characteristic is included in at least one embodiment or example of the present disclosure. The illustrative appearances of the above-mentioned terms in various places in the specification are not necessarily referred to the same embodiment or example. Moreover, the particular features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples. Furthermore, the terminology "comprising" is used in the disclosure as comprising, but not limited to, any indicated features, integers, steps or components. It is also to be understood that the terminology "comprising" can be replaced by the terminology "consisting of" or "consisting essentially of" in some embodiments or examples.

[0070] Although the above-mentioned embodiments have been shown and described, it is to be understood that the above-mentioned embodiments are exemplary, and should not be understood as limiting the present disclosure, and the changes, modifications, replacements and variations of the above-mentioned embodiments made by those skilled in the art are within the protection scope of the present disclosure.

Claims

1. A carbon dioxide capture coupled with waste heat recovery system, characterized in that, include: The collection assembly includes an absorption tower, a regeneration tower, and a drying tower connected in sequence. A lean-rich liquid heat exchanger is provided between the absorption tower and the regeneration tower. A portion of the rich liquid flowing out of the absorption tower exchanges heat with the lean liquid flowing out of the regeneration tower through the lean-rich liquid heat exchanger, and the flow rates of the rich liquid and the lean liquid through the lean-rich liquid heat exchanger are matched. A reboiler is provided at the bottom of the regeneration tower, which is used to heat the rich liquid flowing into the regeneration tower using steam as a heat source. The drying tower has a drying mode and a regeneration mode. In the drying mode, the drying tower is used to adsorb moisture in the regeneration gas generated by heating the rich liquid in the regeneration tower using a desiccant. In the regeneration mode, the drying tower is used to heat and regenerate the desiccant after adsorption saturation. A heat exchange assembly is connected to the absorption tower, the regeneration tower, the reboiler, and the drying tower. The heat exchange assembly is used to preheat another part of the rich liquid flowing out of the absorption tower by using the steam generated after heating and regenerating the rich liquid from the reboiler, the regeneration gas generated after heating the rich liquid from the regeneration tower, and / or the water vapor generated after heating and regenerating the desiccant from the drying tower as heat sources. A power generation assembly, comprising a connected boiler and a turbine unit, the turbine unit being connected to the reboiler to extract steam from the turbine unit as a heat source for the reboiler; The heat exchange assembly includes a first heat exchanger, which is connected to the absorption tower, the regeneration tower, the reboiler, and the boiler, so that the steam after the reboiler heats and regenerates the rich liquid preheats the rich liquid flowing out of the absorption tower in the first heat exchanger, and the rich liquid preheated by the first heat exchanger and the rich liquid that has exchanged heat through the lean and rich liquid heat exchanger flow together into the regeneration tower. The heat exchange assembly further includes a second heat exchanger, which is connected to the absorption tower and the regeneration tower, so that the regeneration gas generated by the regeneration tower heating the rich regeneration liquid preheats the rich liquid flowing out of the absorption tower in the second heat exchanger, and the rich liquid preheated by the second heat exchanger flows into the regeneration tower together with the rich liquid that has exchanged heat through the lean and rich liquid heat exchanger.

2. The carbon dioxide capture coupled waste heat recovery system according to claim 1, characterized in that, A first water cooler is provided between the first heat exchanger and the boiler so that the steam after preheating the rich liquid in the first heat exchanger is condensed by the first water cooler and returned to the boiler.

3. The carbon dioxide capture coupled waste heat recovery system according to claim 1, characterized in that, The collection assembly further includes a second water cooler, a regenerated gas separator, and a centrifugal compressor unit connected in sequence. The second water cooler is connected to the second heat exchanger so that the regenerated gas, after being preheated and enriched in the second heat exchanger, is condensed by the second water cooler and then flows to the regenerated gas separator for separation. The gaseous medium separated by the regenerated gas separator is carbon dioxide gas, and the carbon dioxide gas flows to the centrifugal compressor unit and is compressed from a gaseous state to a liquid state. The centrifugal compressor unit is connected to the drying tower so that the initially pressurized carbon dioxide gas flows to the drying tower for drying and then flows back to the centrifugal compressor unit.

4. The carbon dioxide capture coupled waste heat recovery system according to claim 3, characterized in that, The drying towers are multiple, and at least one of the drying towers operates in the drying mode, and at least one of the drying towers operates in the regeneration mode; The drying tower operates in the drying mode, and the carbon dioxide gas flowing into the drying tower is dried by the desiccant and then flows back to the centrifugal compressor unit. The drying tower operates in the regeneration mode, and the carbon dioxide gas flowing into the drying tower is used as a heating medium for desiccant regeneration.

5. The carbon dioxide capture coupled waste heat recovery system according to claim 4, characterized in that, The trapping assembly also includes an electric heater connected to the drying tower. When the drying tower is operating in the regeneration mode, carbon dioxide gas flows to the electric heater for heating. The heated carbon dioxide gas then flows back into the drying tower to heat and regenerate the desiccant and generate water vapor, thus producing a mixture of carbon dioxide gas and water vapor.

6. The carbon dioxide capture coupled waste heat recovery system according to claim 5, characterized in that, The heat exchange assembly further includes a third heat exchanger, which is connected to the absorption tower, the regeneration tower and the drying tower, so that the mixed gas in the drying tower preheats the rich liquid flowing out of the absorption tower in the third heat exchanger, and the rich liquid preheated by the third heat exchanger and the rich liquid that has exchanged heat through the lean-rich liquid heat exchanger flow together into the regeneration tower.

7. The carbon dioxide capture coupled waste heat recovery system according to claim 6, characterized in that, The trapping assembly also includes a connected third water cooler and a dry gas separator. The third water cooler is connected to the third heat exchanger so that the preheated liquid-rich mixed gas from the third heat exchanger is condensed by the third water cooler and then flows to the dry gas separator for separation. The dry gas separator is connected to the drying tower so that the gaseous medium separated by the dry gas separator flows to the drying tower operating the drying mode for drying and then flows back to the centrifugal compressor unit.

8. The carbon dioxide capture coupled waste heat recovery system according to any one of claims 3-7, characterized in that, The centrifugal compressor unit includes a series of centrifugal compressors connected in sequence. The inlet of the drying tower is connected to the centrifugal compressor located at the upper stage via a pipeline, and the outlet of the drying tower is connected to the centrifugal compressor located at the lower stage via a pipeline.

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