Carbon dioxide trapping coupling waste heat recycling system

Abstract

The invention discloses a carbon dioxide capture coupling waste heat recycling system, the system comprises a capture assembly and a heat exchange assembly, the capture assembly comprises an absorption tower, a regeneration tower and a drying tower, a rich and lean solution heat exchanger is arranged between the absorption tower and the regeneration tower, and a part of rich solution exchanges heat with lean solution through the rich and lean solution heat exchanger; and the flow of the rich solution and the flow of the barren solution of the barren-rich solution heat exchanger are matched, so that the expected heating effect of the rich solution is ensured. The bottom of the regeneration tower is provided with a reboiler, the reboiler utilizes steam to heat rich liquid to generate regenerated gas, the regenerated gas is dried in the drying tower by utilizing a drying agent, the drying agent can be heated and regenerated, and the heat exchange assembly is connected with the absorption tower, the regeneration tower and the drying tower. And the other part of the pregnant solution is preheated by using the waste heat of the used steam, the regenerated gas and / or the water vapor generated by regeneration of the drying agent, so that the energy utilization rate is increased, the energy consumption is reduced, and the pregnant solution is ensured to achieve an expected heating effect.

Description

Technical Field

[0001] The present invention relates to the technical field of flue gas purification, and in particular to a carbon dioxide capture coupled waste heat recovery system. Background Art

[0002] Carbon dioxide in flue gas produced by the combustion of fossil fuels is one of the main greenhouse gases and will aggravate global warming. Some power plants install carbon capture systems after the boilers to capture carbon dioxide in the flue gas discharged by the boilers, thereby reducing carbon dioxide emissions and protecting the environment.

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

[0004] The absorbent after capturing carbon dioxide flowing out of the absorption tower is a low-temperature rich liquid, and the absorbent after heating and desorption flowing out of the regeneration tower is a high-temperature lean liquid. In the related art, a lean-rich liquid heat exchanger is arranged between the absorption tower and the regeneration tower to realize heat exchange between the low-temperature rich liquid and the high-temperature lean liquid, so as to preheat the low-temperature rich liquid and precool the high-temperature lean liquid, improve energy utilization, and reduce energy consumption.

[0005] However, the flow rates of the low-temperature rich liquid and the high-temperature lean liquid do not match, which limits the temperature rise of the low-temperature rich liquid and makes it impossible to achieve the expected temperature rise effect. Summary of the invention

[0006] The present invention is based on the inventor's discovery and understanding of the following facts and problems:

[0007] In the related art, 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 will flow out of the regeneration tower together with the water vapor, resulting in the loss of the regenerated lean liquid. The amount of lean liquid is lower than that of rich liquid, which leads to the flow mismatch between the lean liquid and the rich liquid in the lean-rich liquid heat exchanger, and the rich liquid cannot achieve the expected heating effect.

[0008] In addition, a reboiler is provided at the bottom of the regeneration tower, and steam from the power generation system is extracted as the heat source of the reboiler to heat and regenerate the absorbent, and the used steam flows back to the power generation system. The regeneration gas flowing out of the regeneration tower is subsequently dehydrated and compressed, and finally the compressed carbon dioxide is sealed. The regeneration gas is first condensed and separated from the water by a cooler and a separator, and then passes through a drying tower and uses a desiccant to remove the water. The adsorption saturated desiccant can be heated and regenerated.

[0009] However, the heat in the steam used in the reboiler, the heat in the regeneration gas flowing out of the regeneration tower, and the heat in the water vapor for heating and regenerating the desiccant are not fully utilized, resulting in a problem of energy waste.

[0010] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

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

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

[0013] A capture component, the capture component comprises 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 part of the rich liquid flowing out of the absorption tower is heat-exchanged with the lean liquid flowing out of the regeneration tower through the lean-rich liquid heat exchanger, and the flow rate of the rich liquid passing through the lean-rich liquid heat exchanger matches the flow rate of the lean liquid, a reboiler is provided at the bottom of the regeneration tower, the reboiler is used to use steam as a heat source to heat the rich liquid flowing into the regeneration tower, the drying tower has a drying mode and a regeneration mode, in the drying mode, the drying tower is used to use a desiccant to absorb moisture in the regeneration gas generated by heating the rich liquid in the regeneration tower, and in the regeneration mode, the drying tower is used to heat the desiccant after regeneration adsorption saturation;

[0014] A heat exchange component is connected to the absorption tower, the regeneration tower, the reboiler and the drying tower. The heat exchange component is used to utilize the steam after the rich liquid is heated and regenerated in the reboiler, the regeneration gas generated by the rich liquid heated in the regeneration tower and / or the water vapor generated by the desiccant heated and regenerated in the drying tower as heat sources to preheat another part of the rich liquid flowing out of the absorption tower.

[0015] The carbon dioxide capture coupled waste heat recovery system of the embodiment of the present invention divides the rich liquid flowing out of the absorption tower into two parts. One part of the rich liquid is preheated by the lean liquid, and the flow rate of the rich liquid matches the flow rate of the lean liquid to ensure the expected heating effect. The remaining part of the rich liquid is preheated by the waste heat of the capture and regeneration process, which fully utilizes the waste heat of the capture and regeneration process, not only improving energy utilization and reducing energy consumption, but also ensuring that the rich liquid achieves the expected heating effect.

[0016] In some embodiments, the carbon dioxide capture coupled waste heat recovery system also includes a power generation component, which includes a connected boiler and a steam turbine unit, and the steam turbine unit is connected to the reboiler to extract steam from the steam turbine unit as a heat source for the reboiler. The heat exchange component includes a first heat exchanger, and the first heat exchanger is connected to the absorption tower, the regeneration tower, the reboiler and the boiler, so that the steam after heating and regenerating the rich liquid in the reboiler 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 flows into the regeneration tower together with the rich liquid heat exchanged by the lean-rich liquid heat exchanger.

[0017] In some embodiments, a first water cooler is provided between the first heat exchanger and the boiler, so that the preheated liquid-rich steam of the first heat exchanger is condensed through the first water cooler and then returned to the boiler.

[0018] In some embodiments, the heat exchange component also includes a second heat exchanger, which is connected to the absorption tower and the regeneration tower, so that the regeneration gas generated by heating the regenerated rich liquid in the regeneration tower 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 heat exchanged by the lean-rich liquid heat exchanger.

[0019] In some embodiments, the capture assembly also includes a second water cooler, a regeneration gas separator and a centrifugal compressor unit connected in sequence, the second water cooler is connected to the second heat exchanger so that the preheated liquid-rich regeneration gas of the second heat exchanger is condensed through the second water cooler and then flows to the regeneration gas separator for separation, the gaseous medium separated by the regeneration gas separator is carbon dioxide gas, and the carbon dioxide gas flows to the centrifugal compressor unit and is compressed from gas to liquid, 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.

[0020] In some embodiments, there are a plurality of drying towers, 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;

[0021] The drying tower operates in the drying mode, and the carbon dioxide gas flowing to the drying tower is dried by the desiccant and then flows back to the centrifugal compressor unit;

[0022] The drying tower operates in the regeneration mode, and the carbon dioxide gas flowing to the drying tower is used as a heating medium for regenerating the desiccant.

[0023] In some embodiments, the capture assembly further includes an electric heater connected to the drying tower. The carbon dioxide gas in the drying tower running the regeneration mode flows to the electric heater for heating. The heated carbon dioxide gas flows back into the drying tower to heat the regenerated desiccant and generate water vapor, thereby generating a mixture of carbon dioxide gas and water vapor.

[0024] In some embodiments, the heat exchange component also includes a third heat exchanger, which is connected to the absorption tower, the regeneration tower and the drying tower, so that the mixed gas from 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 flows into the regeneration tower together with the rich liquid heat exchanged by the lean-rich liquid heat exchanger.

[0025] In some embodiments, the capture 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 of the third heat exchanger is condensed through the third water cooler and then flows to the dry gas separator for separation, and the dry gas separator is connected to the drying tower so that the gas phase medium separated by the dry gas separator flows to the drying tower running the drying mode for drying and then flows back to the centrifugal compressor unit.

[0026] In some embodiments, the centrifugal compressor unit includes multiple stages of centrifugal compressors connected in sequence, the inlet of the drying tower is connected to the centrifugal compressor at the upper stage via a pipeline, and the outlet of the drying tower is connected to the centrifugal compressor at the lower stage via a pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of a carbon dioxide capture coupled waste heat recovery system according to an embodiment of the present invention.

[0028] Reference numerals:

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

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

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

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

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

[0034] A lean-rich liquid heat exchanger 3 is provided between the absorption tower 1 and the regeneration tower 2. A portion of the rich liquid flowing out of the absorption tower 1 is heat exchanged with the lean liquid flowing out of the regeneration tower 2 through the lean-rich liquid heat exchanger 3, and the flow of the rich liquid through the lean-rich liquid heat exchanger 3 matches the flow of the lean liquid to ensure that the rich liquid can achieve the expected heating effect, avoiding the problem in the related art that the lean liquid and rich liquid flow rates do not match, resulting in the rich liquid not being able to achieve the expected heating effect. The other 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 the related art failing to achieve the expected heating effect is that the flow rate of the rich liquid is greater than the flow rate of the lean liquid. The carbon dioxide capture coupled waste heat recovery system of the embodiment of the present invention extracts a portion of the rich liquid and uses other means to preheat it, thereby reducing the flow rate of the rich liquid for heat exchange with the lean liquid, so that the flow rate of the remaining rich liquid matches the flow rate of the lean liquid, thereby achieving the expected heating effect.

[0036] A reboiler 4 is provided at the bottom of the regeneration tower 2. Steam is extracted from the power generation system of the power plant as a heat source. The absorbent in the regeneration tower 2 flows into the reboiler 4 and is heated and regenerated by steam. The generated regeneration gas includes carbon dioxide and water, both of which are in gaseous state. After the steam and the absorbent exchange heat in the reboiler 4, the temperature of the steam decreases. Therefore, the remaining heat in the steam after the temperature decreases and the heat in the regeneration gas can be used to preheat the part of the rich liquid that exceeds the flow rate of the lean liquid flowing out of the absorption tower 1.

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

[0038] Thus, the heat exchange component is connected to the absorption tower 1, the regeneration tower 2, the reboiler 4 and the drying tower 5. The steam after cooling through the reboiler 4, the regeneration 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 component, and the part of the rich liquid that exceeds the lean liquid flow rate flowing out of the absorption tower 1 is also transported to the heat exchange component, so as to make full use of the waste heat in the carbon capture regeneration process to preheat the rich liquid, which not only improves the energy utilization rate and reduces energy consumption, but also achieves the expected heating effect.

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

[0040] The carbon dioxide capture coupled waste heat recovery system of the embodiment of the present invention has multiple heat sources for preheating the rich liquid, thereby increasing the amount of additional rich liquid extracted so that the absorbent can carry more carbon dioxide, thereby improving the carbon dioxide capture efficiency.

[0041] Alternatively, if Figure 1 As shown, the carbon dioxide capture coupled waste heat recovery system of the embodiment of the present invention also includes a power generation component. The power generation component includes a boiler 6 and a steam turbine unit 7, and the boiler 6 is connected to the steam turbine unit 7. The boiler 6 sends steam into the steam turbine unit 7 to perform 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 to the reboiler 4 to extract steam from the medium-pressure cylinder as a heat source for the reboiler 4.

[0042] It is understandable that the advantage of extracting steam from the medium-pressure cylinder is balanced 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. Extracting steam from the high-pressure cylinder will affect the power generation effect. The steam quality of the low-pressure cylinder is low, and the effect of heating and regenerating the absorbent in the reboiler 4 is poor.

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

[0044] Furthermore, the preheating effect of the cooled steam on the rich liquid is substantially the same as the preheating effect of the lean liquid on the rich liquid, 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 provided between the first heat exchanger 8 and the boiler 6, so that the steam after preheating rich liquid through the first heat exchanger 8 flows into the first water cooler 9 and condenses into water, and then returns to the boiler 6. The cold source of the first water cooler 9 comes from the cooling water transported by the water cooling tower of the power plant.

[0046] Therefore, the first heat exchanger 8 is used to recycle the waste heat in the steam after the temperature is reduced by the reboiler 4, thereby improving the energy utilization rate and cooperating with the system to reduce consumption during the carbon capture and regeneration process.

[0047] In some embodiments, Figure 1 As shown, the heat exchange assembly also includes a second heat exchanger 10, which is connected to the absorption tower 1 and the regeneration tower 2. The regeneration gas generated by heating and regenerating the rich liquid in the regeneration tower 2 is transported to the second heat exchanger 10, and a portion of the rich liquid flowing out of the absorption tower 1 is also extracted and transported to the second heat exchanger 10, and the heat in the regeneration gas is used to preheat the rich liquid, so as to realize the waste heat recycling of the regeneration gas and improve the energy utilization rate.

[0048] Furthermore, the preheating effect of the regeneration gas on the rich liquid is substantially the same as the preheating effect of the lean liquid on the rich liquid, so that the rich liquid preheated by the second heat exchanger 10 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.

[0049] Alternatively, if Figure 1 As shown, the capture assembly further includes a second water cooler 11, a regeneration gas separator 12 and a centrifugal compressor unit 13 which are connected in sequence.

[0050] The second water cooler 11 is connected to the second heat exchanger 10. The regenerated gas flowing out of the regeneration tower 2 passes through the second heat exchanger 10 for heat exchange and cooling and then flows into the second water cooler 11. The cold source of the second water cooler 11 comes from the cooling water delivered by the water cooling tower of the power plant, and the cooling water is used to condense the moisture in the regenerated gas.

[0051] The condensed regeneration gas flows into the regeneration gas separator 12 for separation, and the separated liquid phase medium is weak alkaline water, which is replenished into the water circulation pipeline of the carbon capture system. The separated gas phase medium is carbon dioxide gas, and the carbon dioxide gas flows into the centrifugal compressor unit 13 to be compressed from gas to liquid, and the liquid carbon dioxide finally produced is transported to underground storage or industrial product preparation through pipelines.

[0052] The centrifugal compressor unit 13 is connected to the drying tower 5 so that the initially pressurized carbon dioxide gas flows into the drying tower 5 for drying and then flows back to the centrifugal compressor unit 13. The initial pressurization of the carbon dioxide gas helps to capture and remove moisture therein.

[0053] For example, the centrifugal compressor unit 13 includes a multi-stage centrifugal compressor connected in sequence via pipelines, and the multi-stage centrifugal compressors are defined as a first-stage centrifugal compressor, an intermediate-stage centrifugal compressor, and a final-stage centrifugal compressor from upstream to downstream of the gas flow. The first-stage centrifugal compressor is connected to the regeneration gas separator 12 so that the carbon dioxide separated by the regeneration gas separator 12 flows to the first-stage centrifugal compressor and the intermediate-stage centrifugal compressor for compression. The intermediate-stage centrifugal compressor is connected to the inlet of the drying tower 5 to extract the carbon dioxide after preliminary compression and enter 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 into a liquid state.

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

[0055] It is understandable that when the desiccant in the drying tower 5 which is running the drying mode is saturated with adsorption, the carbon dioxide gas is switched to the drying tower 5 after the heating and regeneration of the desiccant is completed, so as to ensure the continuity of the carbon dioxide gas drying process and improve the drying efficiency.

[0056] When the drying tower 5 operates in a 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 and then flows into the drying tower 5 as a heating medium for desiccant regeneration. After the desiccant regeneration is completed, the carbon dioxide gas is dried and then flows back to the centrifugal compressor unit 13.

[0058] In this way, the system's own products are fully utilized, and there is no need to introduce external heating medium, which avoids the need to change the tower and increase economic costs.

[0059] Alternatively, if Figure 1 As shown, the capture assembly further includes an electric heater 14, which is connected to the drying tower 5. When the drying tower 5 operates in the regeneration mode, the carbon dioxide gas extracted from the centrifugal compressor unit 13 flows to the electric heater 14 for heating, and the heated carbon dioxide gas flows back into the drying tower 5 to heat and regenerate the desiccant. The product of the heating and regeneration of the desiccant is water vapor, so as to produce a mixed gas of carbon dioxide gas and water vapor.

[0060] The heat exchange assembly also includes a third heat exchanger 15, which is connected to the absorption tower 1, the regeneration tower 2 and the drying tower 5. The mixed gas generated by heating and regenerating the desiccant in the drying tower 5 is transported to the third heat exchanger 15, and a portion of the rich liquid flowing out of the absorption tower 1 is also extracted and transported to the third heat exchanger 15, and the heat in the mixed gas is used to preheat the rich liquid, so as to realize the waste heat recycling of the mixed gas and improve the energy utilization rate.

[0061] Furthermore, the preheating effect of the mixed gas on the rich liquid is substantially the same as the preheating effect of the lean liquid on the rich liquid, 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 capture assembly also includes a third water cooler 16 and a dry gas separator 17 connected to each other. The cooling source of the third water cooler 16 comes from the cooling water delivered by the water cooling tower of the power plant. The third water cooler 16 is connected to the third heat exchanger 15 so that the mixed gas after heat exchange and temperature reduction through the third heat exchanger 15 flows into the third water cooler 16, and the water vapor in the mixed gas is condensed by the cooling water.

[0063] The condensed mixed gas flows into the dry gas separator 17 for separation, and the separated condensate is directly discharged to the wastewater treatment system of the power plant or used for coal plant spraying or for ash accompanying. The separated carbon dioxide gas flows into the drying tower 5 which is running in the drying mode for drying, and then flows back to the centrifugal compressor unit 13 for compression.

[0064] The carbon dioxide capture coupled waste heat recovery system of the embodiment of the present invention rationally utilizes the structure of multiple drying towers 5 to send a portion of the initially pressurized carbon dioxide gas into the drying tower 5 operating in the drying mode for direct drying treatment. The other portion is sent to the drying tower 5 operating in the regeneration mode, and after being heated by the electric heater 14, it is first used in the heating regeneration process of the adsorbed saturated desiccant. After the desiccant is regenerated, the mixed gas is condensed and separated, and the separated carbon dioxide gas is then sent to the drying tower 5 operating in the drying mode for drying treatment. In this way, not only the continuity of carbon dioxide drying is ensured and the drying efficiency is improved, but also the system's ability to coordinate and cooperate is highlighted, thereby improving the value of the system itself.

[0065] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0066] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0067] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0068] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean 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, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0069] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0070] Although the above embodiments have been shown and described, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. Changes, modifications, substitutions and variations of the above embodiments by those of ordinary skill in the art are all within the scope of protection of the present invention.

Claims

1. A carbon dioxide capture coupled waste heat recovery system, characterized in that: include: A capture component, the capture component comprises 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 part of the rich liquid flowing out of the absorption tower is heat-exchanged with the lean liquid flowing out of the regeneration tower through the lean-rich liquid heat exchanger, and the flow rate of the rich liquid passing through the lean-rich liquid heat exchanger matches the flow rate of the lean liquid, a reboiler is provided at the bottom of the regeneration tower, the reboiler is used to use steam as a heat source to heat the rich liquid flowing into the regeneration tower, the drying tower has a drying mode and a regeneration mode, in the drying mode, the drying tower is used to use a desiccant to absorb moisture in the regeneration gas generated by heating the rich liquid in the regeneration tower, and in the regeneration mode, the drying tower is used to heat the desiccant after regeneration adsorption saturation; A heat exchange component is connected to the absorption tower, the regeneration tower, the reboiler and the drying tower. The heat exchange component is used to utilize the steam after the rich liquid is heated and regenerated in the reboiler, the regeneration gas generated by the rich liquid heated in the regeneration tower and / or the water vapor generated by the desiccant heated and regenerated in the drying tower as heat sources to preheat another part of the rich liquid flowing out of the absorption tower.

2. The carbon dioxide capture coupled waste heat recovery system according to claim 1 is characterized in that: It also includes a power generation component, which includes a connected boiler and a steam turbine unit. The steam turbine unit is connected to the reboiler to extract steam from the steam turbine unit as a heat source for the reboiler. The heat exchange component 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 heating and regenerating the rich liquid in the reboiler 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 flows into the regeneration tower together with the rich liquid heat exchanged by the lean-rich liquid heat exchanger.

3. The carbon dioxide capture coupled waste heat recovery system according to claim 2 is characterized in that: A first water cooler is provided between the first heat exchanger and the boiler, so that the preheated liquid-rich steam of the first heat exchanger is condensed through the first water cooler and then returned to the boiler.

4. The carbon dioxide capture coupled waste heat recovery system according to claim 2 is characterized in that: The heat exchange component also includes a second heat exchanger, which is connected to the absorption tower and the regeneration tower, so that the regeneration gas generated by heating the regenerated rich liquid in the regeneration tower 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 heat exchanged by the lean-rich liquid heat exchanger.

5. The carbon dioxide capture coupled waste heat recovery system according to claim 4 is characterized in that: The capture assembly also includes a second water cooler, a regeneration gas separator and a centrifugal compressor unit connected in sequence. The second water cooler is connected to the second heat exchanger so that the regeneration gas after preheating and enriching the liquid in the second heat exchanger is condensed through the second water cooler and then flows to the regeneration gas separator for separation. The gaseous medium separated by the regeneration gas separator is carbon dioxide gas, and the carbon dioxide gas flows to the centrifugal compressor unit and is compressed from gas to liquid. 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.

6. The carbon dioxide capture coupled waste heat recovery system according to claim 5 is characterized in that: There are a plurality of drying towers, at least one of which operates in the drying mode, and at least one of which operates in the regeneration mode; The drying tower operates in the drying mode, and the carbon dioxide gas flowing to 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 to the drying tower is used as a heating medium for regenerating the desiccant.

7. The carbon dioxide capture coupled waste heat recovery system according to claim 6 is characterized in that: The capture component also includes an electric heater, which is connected to the drying tower. The carbon dioxide gas in the drying tower running the regeneration mode flows to the electric heater for heating, and the heated carbon dioxide gas flows back into the drying tower to heat the regenerated desiccant and generate water vapor, so as to produce a mixed gas of carbon dioxide gas and water vapor.

8. The carbon dioxide capture coupled waste heat recovery system according to claim 7 is characterized in that: The heat exchange assembly also 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 flows into the regeneration tower together with the rich liquid heat exchanged by the lean-rich liquid heat exchanger.

9. The carbon dioxide capture coupled waste heat recovery system according to claim 8, characterized in that: The capture 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 of the third heat exchanger is condensed through 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 gas phase medium separated by the dry gas separator flows to the drying tower running the drying mode for drying and then flows back to the centrifugal compressor unit.

10. The carbon dioxide capture coupled waste heat recovery system according to any one of claims 5 to 9, characterized in that: The centrifugal compressor unit includes multiple stages of centrifugal compressors connected in sequence. The inlet of the drying tower is connected to the centrifugal compressor at the upper stage via a pipeline, and the outlet of the drying tower is connected to the centrifugal compressor at the lower stage via a pipeline.

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