A high-temperature steam heat pump-based carbon capture waste heat recovery and utilization system

Abstract

The application relates to the technical field of flue gas carbon dioxide recovery, and discloses a carbon capture waste heat recovery and utilization system based on a high-temperature steam heat pump. The carbon capture waste heat recovery and utilization system comprises a carbon dioxide absorption tower and a desorption tower which are connected to absorb carbon dioxide and make the enriched liquid after absorption desorb in the desorption tower. The high-temperature steam heat pump comprises an evaporator, an efficient device, a compressor and a steam generator which are connected in sequence through pipelines. The outlet of the heat medium side channel of the evaporator is connected with the carbon dioxide absorption tower. The refrigerant discharged from the outlet of the refrigerant channel of the evaporator enters the cold medium side channel of the efficient device, the compressor and the steam generator in sequence. The refrigerant after heat exchange in the steam generator returns to the evaporator through the heat medium side channel of the efficient device. The steam generator is connected with the desorption tower. The heat of the flue gas is recovered by the refrigerant to generate steam for the desorption tower, so that the energy loss of steam generation is reduced, and the external energy consumption of the desorption process is reduced.

Description

Technical Field

[0001] This application relates to the field of flue gas carbon dioxide recovery technology, for example to a carbon capture waste heat recovery and utilization system based on a high-temperature steam heat pump. Background Technology

[0002] CO2 capture and utilization in power plants is a crucial technological pathway for emission reduction. It allows for the conversion and utilization of CO2 into resources and energy, generating economic benefits simultaneously. Currently, the amine method is widely used, as amine solutions exhibit excellent carbon dioxide absorption performance, achieving high capture efficiency. However, the desorption process consumes a significant amount of heat, resulting in high energy consumption for the entire carbon capture system, and the capture process also generates waste heat.

[0003] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this application, and therefore may include information that does not constitute prior art known to those skilled in the art. Utility Model Content

[0004] To provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. This summary is not intended as a general commentary, nor is it intended to identify key / important components or describe the scope of protection of these embodiments, but rather as a prelude to the detailed description that follows.

[0005] This disclosure provides a carbon capture waste heat recovery and utilization system based on a high-temperature steam heat pump. Through the cooperation of various devices of the high-temperature steam heat pump, steam is directly generated by absorbing waste heat from flue gas and supplied to the desorption tower, thereby reducing the energy loss of steam production, improving the electrothermal conversion efficiency, and reducing the external energy consumption of the desorption process.

[0006] In some embodiments, a carbon capture waste heat recovery and utilization system based on a high-temperature steam heat pump includes: A carbon dioxide absorption tower and a desorption tower are connected to absorb flue gas and then send the rich liquid after absorption to the desorption tower for desorption. The high-temperature steam heat pump includes an evaporator, a high-efficiency unit, a compressor, and a steam generator connected in sequence via pipelines. The outlet of the heat medium side channel of the evaporator is connected to a carbon dioxide absorption tower, and the inlet of the heat medium side channel of the evaporator is connected to a flue gas source. The refrigerant discharged from the outlet of the refrigerant channel of the evaporator enters the refrigerant side channel of the high-efficiency unit, the compressor, and the steam generator in sequence. The refrigerant after heat exchange in the steam generator returns to the evaporator after passing through the heat medium side channel of the high-efficiency unit. The steam generator is connected to a desorption tower. The water in the steam generator absorbs the heat of the high-temperature refrigerant and evaporates directly into steam, which is then supplied to the desorption tower to heat the rich liquid in the desorption tower.

[0007] Optionally, the carbon capture waste heat recovery system also includes a direct contact heat exchanger. The flue gas passage of the direct contact heat exchanger is connected to the carbon dioxide absorption tower, and the circulating water passage of the direct contact heat exchanger is connected to the heat medium side passage of the evaporator. The heat medium side passage in the evaporator exchanges heat with the refrigerant passage to recover waste heat from the flue gas through the circulating water and heat the refrigerant in the evaporator.

[0008] Optionally, the high-temperature steam heat pump also includes a preheater. The preheater is equipped with a water supply channel and a refrigerant channel. The refrigerant discharged from the steam generator exchanges heat with the water supply through the refrigerant channel of the preheater and then enters the heat medium side channel of the high-efficiency unit. The water supply channel of the preheater is connected to the steam generator so as to preheat the water entering the steam generator with the waste heat of the refrigerant.

[0009] Optionally, the high-temperature steam heat pump also includes a reboiler connected to the desorption tower, and a steam generator connected to the reboiler to heat the rich liquid in the desorption tower with steam generated by the steam generator.

[0010] Optionally, the high-temperature steam heat pump also includes an economizer, wherein the refrigerant passage of the preheater is connected to the inlet of the heat medium side passage of the economizer, and the outlet of the heat medium side passage of the economizer is connected to the heat medium side passage of the high-efficiency unit. A branched gas supply circuit is installed on the pipeline connecting the economizer and the high-efficiency unit. The refrigerant outlet of the gas supply circuit is connected to the inlet of the refrigerant side channel of the economizer, and the outlet of the refrigerant side channel of the economizer is connected to the compressor. This allows the refrigerant heat exchanged between the refrigerant heat exchange channel of the economizer and the gas supply circuit, so that the refrigerant that has absorbed heat in the gas supply circuit is supplied to the compressor.

[0011] Optionally, the high-temperature steam heat pump also includes a first expansion valve, which is located on the pipeline connecting the inlet of the refrigerant passage of the evaporator and the outlet of the heat medium side passage of the high-efficiency unit.

[0012] Optionally, the carbon dioxide absorption tower is provided with a lean liquid inlet, and the rich liquid passage connecting the carbon dioxide absorption tower and the desorption tower is provided with two channels. One of the rich liquid passages is provided with a lean-rich liquid heat exchanger. The lean liquid outlet of the desorption tower is connected to the lean-rich liquid heat exchanger, and the lean liquid outlet of the lean-rich liquid heat exchanger is connected to the lean liquid inlet of the carbon dioxide absorption tower, so that the rich liquid and the lean liquid can exchange heat through the lean-rich liquid heat exchanger.

[0013] Optionally, the carbon capture waste heat recovery system also includes an interstage cooler. The cooling channels of the interstage cooler are connected to the first liquid outlet and the first liquid inlet of the carbon dioxide absorption tower, respectively. The first liquid outlet is located above the first liquid inlet, and the first liquid inlet is located above the flue gas inlet of the carbon dioxide absorption tower, so as to cool the lean liquid in the absorption tower.

[0014] Optionally, the carbon capture waste heat recovery system also includes a scrubbing liquid cooler, which has a flue gas inlet and a flue gas outlet respectively connected to the top of the carbon dioxide absorption tower, so that the flue gas is cooled by passing through the scrubbing liquid cooler.

[0015] Optionally, the carbon capture waste heat recovery system also includes a gas-liquid separator, with the desorption tower having a gas outlet connected to the inlet of the gas-liquid separator.

[0016] The carbon capture waste heat recovery and utilization system based on a high-temperature steam heat pump provided in this disclosure can achieve the following technical effects: The carbon dioxide absorption tower absorbs carbon dioxide from the flue gas, while the desorption tower desorbs carbon dioxide gas from the rich liquid discharged from the carbon dioxide absorption tower. An evaporator, high-efficiency heat exchanger, compressor, and steam generator form a high-temperature steam heat pump. The evaporator or direct-contact heat exchanger absorbs waste heat from the flue gas, serving as a low-temperature heat source for the high-temperature steam heat pump, thus realizing the recovery and utilization of flue gas heat and generating steam to supply the desorption tower, improving electrothermal conversion efficiency and reducing external energy consumption in the decarbonization process. The evaporator, high-efficiency heat exchanger, and steam generator work together to recover waste heat from the flue gas and convert it into heat for the refrigerant. The steam generator directly generates steam using the heat from the refrigerant, avoiding energy loss during the flash steam generation process and improving steam generation efficiency.

[0017] The above general description and the description below are exemplary and illustrative only and are not intended to limit this application. Attached Figure Description

[0018] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations and drawings do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are shown as similar elements. The drawings are not to be scaled. And wherein: Figure 1 This is a schematic diagram of a carbon capture and waste heat recovery system based on a high-temperature steam heat pump, according to the first embodiment of this utility model.

[0019] Figure 2 This is a schematic diagram of a carbon capture and waste heat recovery system based on a high-temperature steam heat pump, according to the second embodiment of this utility model.

[0020] Figure label: 1-Exhaust fan, 2-Carbon dioxide absorption tower, 3-Rich liquid pump, 4-Rich / lean liquid heat exchanger, 5-Desorption tower, 6-Gas-liquid separator, 7-Lean liquid pump, 8-Lean liquid cooler, 9-Interstage cooler, 10-Tail gas scrubbing pump, 11-Scrubber cooler, 12-Reboiler, 13-Steam generator, 14-Preheater, 15-Make-up water valve, 16-Economizer, 17-Second expansion valve, 18-Compressor, 19-High-efficiency unit, 20-First expansion valve, 21-Evaporator, 22-Direct contact heat exchanger, 23-Water pump. Detailed Implementation

[0021] To provide a more detailed understanding of the features and technical content of the embodiments of this disclosure, the implementation of the embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for illustrative purposes only and are not intended to limit the embodiments of this disclosure. In the following technical description, for ease of explanation, several details are used to provide a full understanding of the disclosed embodiments. However, one or more embodiments may still be implemented without these details. In other cases, well-known structures and devices may be simplified in their depiction to simplify the drawings.

[0022] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this disclosure described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0023] In this disclosure, the terms "upper," "lower," "inner," "middle," "outer," "front," and "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for better description of the embodiments of this disclosure and their implementations, and are not intended to limit the indicated devices, elements, or components to having a specific orientation, or to require them to be constructed and operated in a specific orientation. Furthermore, some of the aforementioned terms may be used to indicate other meanings besides orientation or positional relationship; for example, the term "upper" may in some cases indicate a dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in the embodiments of this disclosure according to the specific circumstances.

[0024] Furthermore, the terms "set up," "connect," and "fix" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this disclosure according to the specific circumstances.

[0025] Unless otherwise stated, the term "multiple" means two or more.

[0026] It should be noted that, unless otherwise specified, the embodiments and features described in the present disclosure can be combined with each other.

[0027] Combination Figure 1 This disclosure provides a carbon capture waste heat recovery and utilization system based on a high-temperature steam heat pump. The carbon capture waste heat recovery and utilization system based on a high-temperature steam heat pump includes: a carbon dioxide absorption tower 2 and a desorption tower 5. The carbon dioxide absorption tower 2 is connected to the desorption tower 5 to absorb flue gas, and the rich liquid after absorption is sent to the desorption tower 5 for desorption. The high-temperature steam heat pump includes an evaporator 21, a high-efficiency heat exchanger 19, a compressor 18, and a steam generator 13 connected in sequence by pipelines. The outlet of the heat medium side channel of the evaporator 21 is connected to the carbon dioxide absorption tower 2, and the inlet of the heat medium side channel of the evaporator 21 is connected to the flue gas source. The refrigerant discharged from the outlet of the refrigerant channel of the evaporator 21 enters the refrigerant side channel of the high-efficiency heat exchanger 19, the compressor 18, and the steam generator 13 in sequence. The refrigerant after heat exchange in the steam generator 13 returns to the evaporator 21 after passing through the heat medium side channel of the high-efficiency heat exchanger 19. The steam generator 13 is connected to the desorption tower 5. The water in the steam generator 13 absorbs the heat of the high-temperature refrigerant and evaporates directly into steam, which is then supplied to the desorption tower 5 to heat the rich liquid in the desorption tower 5.

[0028] The evaporator 21 can be a finned tube heat exchanger, which can be a spiral finned tube heat exchanger, etc., and has a good heat exchange effect.

[0029] Carbon dioxide absorption tower 2 is used for the absorption of carbon dioxide from flue gas. The absorbent can be an alkanolamine solution, which has a good absorption effect. Desorption tower 5 is used to desorb the rich liquid discharged from carbon dioxide absorption tower 2 after carbon dioxide absorption, so as to obtain carbon dioxide gas and desorbed lean liquid respectively. The absorbent can be reused to collect and reuse carbon dioxide in flue gas.

[0030] Evaporator 21 allows for heat exchange of the flue gas before it enters the carbon dioxide absorption tower 2, lowering its temperature and facilitating decarbonization. It also enables the recovery of waste heat from the flue gas. This recovered waste heat is then used in the refrigerant heat exchange process of the high-temperature steam heat pump via evaporator 21, facilitating efficient steam generation. Steam generator 13 uses the heat from the refrigerant to heat water and generate steam. The steam from generator 13 can exchange heat with the rich liquid in desorption tower 5, increasing its temperature and improving the desorption efficiency. This reduces external energy consumption during carbon dioxide desorption and increases energy utilization.

[0031] There are many ways to exchange heat between the steam obtained from the steam generator 13 and the rich liquid in the desorption tower 5, such as through the reboiler 12, or by directly installing a heat exchanger in the desorption tower 5.

[0032] The high-temperature steam heat pump of this application uses an evaporator 21, a high-efficiency unit 19, a compressor 18, and a steam generator 13 to directly generate steam. Compared with the flash steam generation method, this method can avoid energy loss in the flash steam generation process, improve steam generation efficiency, and increase electrothermal conversion rate.

[0033] Through the heat exchange process of the high-efficiency unit 19, the low-pressure gaseous refrigerant exchanges heat with the high-pressure refrigerant after heat exchange in the steam generator 13, further increasing the temperature of the low-pressure gaseous refrigerant to obtain superheated gaseous refrigerant. The superheated gaseous refrigerant then enters the compressor 18 for compression to obtain high-temperature, high-pressure refrigerant. This reduces the energy consumption of the high-temperature steam heat pump and improves the steam production efficiency of the steam generator 13.

[0034] like Figure 2 As shown, optionally, the carbon capture waste heat recovery and utilization system also includes a direct contact heat exchanger 22. The flue gas passage of the direct contact heat exchanger 22 is connected to the carbon dioxide absorption tower 2, and the circulating water passage of the direct contact heat exchanger 22 is connected to the heat medium side passage of the evaporator 21. The heat medium side passage in the evaporator 21 exchanges heat with the refrigerant passage to recover the waste heat of the flue gas through the circulating water and heat the refrigerant in the evaporator 21.

[0035] A spray structure can be installed inside the direct contact heat exchanger 22. Through the direct contact heat exchanger 22, low-temperature intermediate circulating water exchanges heat with the flue gas, significantly reducing the water vapor content in the cooled flue gas and releasing a large amount of latent heat of vaporization. The intermediate circulating water absorbs the sensible heat of the flue gas and the latent heat of vaporization of the water vapor, and then exchanges heat with the refrigerant in the heat pump through the evaporator 21. The recovered waste heat is used as a low-temperature heat source for the high-temperature steam heat pump unit to generate high-temperature steam.

[0036] This disclosure allows for heat exchange with flue gas via a direct contact heat exchanger 22 or an evaporator 21. Both methods can effectively recover waste heat from the flue gas and improve the recovery efficiency.

[0037] Optionally, the high-temperature steam heat pump also includes a preheater 14, which is provided with a water supply channel and a refrigerant channel. The refrigerant discharged from the steam generator 13 exchanges heat with the water supply through the refrigerant channel of the preheater 14 and then enters the heat medium side channel of the high-efficiency unit 19. The water supply channel of the preheater 14 is connected to the steam generator 13 so as to preheat the water entering the steam generator 13 by the waste heat of the refrigerant.

[0038] The preheater 14 preheats the water added to the steam generator 13, increasing the water temperature, reducing the energy consumption of the steam generator 13, and improving the steam production efficiency of the steam generator 13, which is beneficial for the desorption of rich liquid in the desorption tower 5. Therefore, adding the preheater 14 and the high-efficiency unit 19 can optimize energy utilization and improve system performance.

[0039] A water supply valve 15 can be installed on the water supply pipe connected to the inlet of the water supply channel of the preheater 14.

[0040] Optionally, the high-temperature steam heat pump also includes a reboiler 12 connected to the desorption tower 5, and a steam generator 13 connected to the reboiler 12 to heat the rich liquid in the desorption tower 5 with steam generated by the steam generator 13.

[0041] The reboiler 12 allows heat exchange between the steam generated by the steam generator and the rich liquor in the desorption tower 5, resulting in a higher-temperature rich liquor and condensate. The higher-temperature rich liquor enters the desorption tower 5 and undergoes stripping to desorb CO2. The desorbed rich liquor becomes lean liquor and flows out from the bottom of the desorption tower 5. The condensate obtained from the reboiler 12 can be used as makeup water, heated by the preheater 14, and then enters the steam generator, achieving the recycling of condensate.

[0042] Optionally, the high-temperature steam heat pump also includes an economizer 16, wherein the refrigerant passage of the preheater 14 is connected to the inlet of the heat medium side passage of the economizer 16, and the outlet of the heat medium side passage of the economizer 16 is connected to the heat medium side passage of the high-efficiency unit 19. A branched gas supply circuit is provided on the pipeline connecting the economizer 16 and the high-efficiency unit 19. The refrigerant outlet of the gas supply circuit is connected to the inlet of the refrigerant side channel of the economizer 16. The outlet of the refrigerant side channel of the economizer 16 is connected to the compressor 18. The heat exchange channel of the economizer 16 and the gas supply circuit exchange heat, so that the refrigerant that has absorbed heat in the gas supply circuit is supplied to the compressor 18.

[0043] The economizer 16 utilizes the waste heat of the refrigerant to heat the refrigerant in the make-up gas circuit. The heated refrigerant then enters the compressor 18 and is compressed into a high-pressure, high-temperature refrigerant, which then enters the steam generator 13 for heat exchange, facilitating better steam generation. Adding a make-up gas circuit effectively widens the operating temperature range of the heat pump.

[0044] Optionally, the high-temperature steam heat pump also includes a first expansion valve 20, which is disposed on the pipeline connecting the inlet of the refrigerant passage of the evaporator 21 and the outlet of the heat medium side passage of the high-efficiency unit 19.

[0045] Optionally, a second expansion valve 17 is provided in the gas replenishment circuit. The refrigerant in the gas replenishment circuit is throttled and depressurized by the second expansion valve 17 and then enters the economizer 16 to absorb heat and become superheated vapor before entering the compressor 18.

[0046] Optionally, the carbon dioxide absorption tower 2 is provided with a lean liquid inlet, and the carbon dioxide absorption tower 2 and the desorption tower 5 are connected by two rich liquid passages. One of the rich liquid passages is provided with a lean-rich liquid heat exchanger 4. The lean liquid outlet of the desorption tower 5 is connected to the lean-rich liquid heat exchanger 4, and the lean liquid outlet of the lean-rich liquid heat exchanger 4 is connected to the lean liquid inlet of the carbon dioxide absorption tower 2, so that the rich liquid and the lean liquid can exchange heat through the lean-rich liquid heat exchanger 4.

[0047] The rich solution (absorbent containing carbon dioxide) obtained from carbon dioxide absorber 2 enters desorption tower 5 directly for desorption, while the other side passes through lean-rich solution heat exchanger 4 to exchange heat with the lean solution before entering desorption tower 5. The rich and lean solutions exchange heat through the lean-rich solution heat exchanger 4, utilizing the residual heat of the lean solution to raise the temperature of the rich solution. After heat exchange, the lean solution returns to carbon dioxide absorber 2 to absorb CO2 from the flue gas, becoming rich solution and flowing out from the bottom of the absorber. This forms a cyclical process of lean and rich solutions, allowing for repeated decarbonization of the flue gas. The increased temperature of the rich solution facilitates the desorption process, improving the desorption efficiency.

[0048] Optionally, the carbon capture waste heat recovery system also includes a lean liquor cooler 8 and a lean liquor pump 7. A lean-rich liquor heat exchanger 4 is connected sequentially to the lean liquor pump 7 and the lean liquor cooler 8. The outlet of the lean liquor cooler 8 is connected to the carbon dioxide absorption tower 2. This allows the lean liquor to be cooled before entering the carbon dioxide absorption tower 2, improving the absorption efficiency of carbon dioxide in the flue gas. The lean liquor, after heat exchange with the rich liquor, undergoes further cooling in the lean liquor cooler 8 before entering the carbon dioxide absorption tower 2, which is beneficial for improving the decarbonization effect of the flue gas.

[0049] Optionally, the carbon capture waste heat recovery and utilization system also includes an interstage cooler 9. The cooling channels of the interstage cooler 9 are connected to the first liquid outlet and the first liquid inlet of the carbon dioxide absorption tower 2, respectively. The first liquid outlet is located above the first liquid inlet, and the first liquid inlet is located above the flue gas inlet of the carbon dioxide absorption tower 2, so as to cool the lean liquid in the carbon dioxide absorption tower 2.

[0050] Interstage cooler 9 cools the absorbent liquid from the middle of carbon dioxide absorption tower 2, thereby improving the absorbent liquid's ability to absorb carbon dioxide from flue gas.

[0051] Optionally, the carbon capture waste heat recovery system also includes a scrubbing liquid cooler 11. The scrubbing liquid cooler 11 has a flue gas inlet and a flue gas outlet respectively connected to the top of the carbon dioxide absorption tower 2, so that the flue gas is cooled by passing through the scrubbing liquid cooler 11. The decarbonization tail gas is washed and cooled by the scrubbing liquid before being discharged.

[0052] Optionally, the carbon capture waste heat recovery system also includes a gas-liquid separator 6. The desorption tower 5 is provided with a gas outlet, which is connected to the inlet of the gas-liquid separator 6. The CO2 desorbed in the desorption tower 5, along with water vapor, exits from the top of the desorption tower 5. After being separated and cooled by the gas-liquid separator 6 to remove moisture, a CO2 product gas with a purity of 99.5% (dry gas) or higher is obtained, which then enters subsequent processing stages such as compression for further treatment.

[0053] like Figure 1 and Figure 2 As shown, the process flow of the carbon capture waste heat recovery and utilization system based on a high-temperature steam heat pump in this application is as follows: Flue gas system flow: After desulfurization, the flue gas is cooled by a direct contact heat exchanger 22 and then sent to the carbon dioxide absorption tower 2 by an induced draft fan 1 for decarbonization treatment. The water vapor content in the cooled flue gas is significantly reduced, releasing a large amount of latent heat of vaporization. The intermediate circulating water can absorb the sensible heat of the flue gas and the latent heat of vaporization of the water vapor. The carbon dioxide absorption tower 2 uses a new type of absorbent to absorb CO2 in the flue gas; the absorbent liquid is cooled from the middle of the carbon dioxide absorption tower 2 by an interstage cooler 9. The decarbonized tail gas is discharged after washing, and the tail gas washing liquid is circulated by the tail gas washing pump 10 and cooled by the washing liquid cooler 11.

[0054] Alternatively, the flue gas and refrigerant exchange heat in the evaporator 21, with the refrigerant directly absorbing heat from the flue gas as a low-temperature heat source for the heat pump cycle system.

[0055] Rich liquor system process: After absorbing CO2 in carbon dioxide absorption tower 2, the absorbent becomes rich liquor. It is then pumped out by rich liquor pump 3 and divided into two streams: one stream directly enters desorption tower 5 for desorption, and the other stream exchanges heat with lean liquor in lean-rich liquor heat exchanger 4 before entering desorption tower 5. Under the heating action of reboiler 12, CO2 in the rich liquor is desorbed through stripping. The desorbed rich liquor becomes lean liquor and flows out from the bottom of desorption tower 5.

[0056] Lean liquor system process: The lean liquor flowing out from the bottom of the desorption tower 5 absorbs the heat of the rich liquor in the lean-rich liquor heat exchanger 4, and then enters the lean liquor cooler 8 through the lean liquor pump 7 for cooling. After cooling, it enters the carbon dioxide absorption tower 2 to absorb CO2 in the flue gas, and becomes rich liquor, which flows out from the bottom of the carbon dioxide absorption tower 2.

[0057] CO2 capture process: The CO2 desorbed in the desorption tower 5, along with water vapor, is discharged from the top of the desorption tower 5 and then separated and cooled by the gas-liquid separator 6 to remove moisture.

[0058] The intermediate circulating water process when the direct contact heat exchanger 22 is set up is as follows: After absorbing the heat of the flue gas in the direct contact heat exchanger 22, the intermediate circulating water is pumped into the evaporator 21 by the water pump 23 to exchange heat with the refrigerant and cool down. Then it enters the direct contact heat exchanger 22 to spray and contact the flue gas for heat exchange.

[0059] Refrigerant flow: The refrigerant of the high-temperature steam heat pump absorbs heat from the intermediate circulating water (or flue gas) in the evaporator 21, evaporating into a low-pressure gaseous state. It then enters the high-efficiency unit 19 to exchange heat with the high-pressure refrigerant, and after further superheating, enters the compressor 18. After compression and enthalpy increase, it becomes a high-temperature, high-pressure gas, releasing heat in the steam generator 13 to heat and soften the water, producing steam. The refrigerant after releasing heat enters the preheater 14 to preheat the makeup water, and then enters the economizer 16 to exchange heat with the refrigerant in the gas replenishment circuit. After heat exchange, the refrigerant is divided into two paths. The refrigerant in the main path enters the high-efficiency unit 19 to release heat, and then enters the evaporator 21 after being throttled and depressurized by the first expansion valve 20, completing the cycle. The refrigerant in the gas replenishment circuit enters the economizer 16 after being throttled and depressurized by the second expansion valve 17, absorbing heat and becoming superheated steam before entering the compressor 18.

[0060] Steam process: After being preheated by the preheater 14, the makeup water enters the steam generator 13, where it absorbs heat from the refrigerant and evaporates directly into steam, which then enters the reboiler 12 to provide heat for the desorption process in the desorption tower 5.

[0061] The foregoing description and accompanying drawings fully illustrate embodiments of the present disclosure to enable those skilled in the art to practice them. Other embodiments may include structural and other changes. The embodiments represent only possible variations. Individual components and functions are optional unless explicitly required, and the order of operation may vary. Parts and features of some embodiments may be included or substituted for parts and features of other embodiments. Embodiments of the present disclosure are not limited to the structures described above and shown in the accompanying drawings, and various modifications and changes may be made without departing from its scope. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A carbon capture and waste heat recovery system based on a high-temperature steam heat pump, characterized in that, include: A carbon dioxide absorption tower and a desorption tower are connected to each other to absorb carbon dioxide and then send the rich liquid after absorption to the desorption tower for desorption. The high-temperature steam heat pump includes an evaporator, a high-efficiency unit, a compressor, and a steam generator connected in sequence via pipelines. The outlet of the heat medium side channel of the evaporator is connected to a carbon dioxide absorption tower, and the inlet of the heat medium side channel of the evaporator is connected to a flue gas source. The refrigerant discharged from the outlet of the refrigerant channel of the evaporator enters the refrigerant side channel of the high-efficiency unit, the compressor, and the steam generator in sequence. The refrigerant after heat exchange in the steam generator returns to the evaporator after passing through the heat medium side channel of the high-efficiency unit. The steam generator is connected to a desorption tower. The water in the steam generator absorbs the heat of the high-temperature refrigerant and evaporates directly into steam, which is then supplied to the desorption tower to heat the rich liquid in the desorption tower.

2. The carbon capture and waste heat recovery system according to claim 1, characterized in that, The carbon capture waste heat recovery system also includes a direct contact heat exchanger. The flue gas passage of the direct contact heat exchanger is connected to the carbon dioxide absorption tower, and the circulating water passage of the direct contact heat exchanger is connected to the heat medium side passage of the evaporator. The heat medium side passage in the evaporator exchanges heat with the refrigerant passage to recover waste heat from the flue gas through the circulating water and heat the refrigerant in the evaporator.

3. The carbon capture and waste heat recovery system according to claim 1 or 2, characterized in that, The high-temperature steam heat pump also includes a preheater, which is equipped with a water supply channel and a refrigerant channel. The refrigerant discharged from the steam generator exchanges heat with the water supply through the refrigerant channel of the preheater and then enters the heat medium side channel of the high-efficiency unit. The water supply channel of the preheater is connected to the steam generator so as to preheat the water entering the steam generator with the waste heat of the refrigerant.

4. The carbon capture and waste heat recovery system according to claim 1 or 2, characterized in that, The high-temperature steam heat pump also includes a reboiler, which is connected to the desorption tower, and a steam generator connected to the reboiler, so as to heat the rich liquid in the desorption tower with steam generated by the steam generator.

5. The carbon capture and waste heat recovery system according to claim 3, characterized in that, The high-temperature steam heat pump also includes an economizer. The refrigerant passage of the preheater is connected to the inlet of the heat medium side passage of the economizer, and the outlet of the heat medium side passage of the economizer is connected to the heat medium side passage of the high-efficiency unit. A branched gas supply circuit is installed on the pipeline connecting the economizer and the high-efficiency unit. The refrigerant outlet of the gas supply circuit is connected to the inlet of the refrigerant side channel of the economizer. The outlet of the refrigerant side channel of the economizer is connected to the compressor. The heat exchange channel of the economizer exchanges heat with the gas supply circuit, so that the refrigerant after heat exchange in the gas supply circuit is supplied to the compressor.

6. The carbon capture waste heat recovery and utilization system according to claim 1 or 2, characterized in that, The high-temperature steam heat pump also includes a first expansion valve, which is located on the pipeline connecting the inlet of the refrigerant channel of the evaporator and the outlet of the heat medium side channel of the high-efficiency unit.

7. The carbon capture and waste heat recovery system according to claim 1 or 2, characterized in that, The carbon dioxide absorption tower is equipped with a lean liquid inlet. There are two rich liquid passages connecting the carbon dioxide absorption tower and the desorption tower. One of the rich liquid passages is equipped with a lean-rich liquid heat exchanger. The lean liquid outlet of the desorption tower is connected to the lean-rich liquid heat exchanger, and the lean liquid outlet of the lean-rich liquid heat exchanger is connected to the lean liquid inlet of the carbon dioxide absorption tower, so that the rich liquid and the lean liquid can exchange heat through the lean-rich liquid heat exchanger.

8. The carbon capture and waste heat recovery system according to claim 1 or 2, characterized in that, The carbon capture waste heat recovery and utilization system also includes an interstage cooler. The cooling channels of the interstage cooler are connected to the first liquid outlet and the first liquid inlet of the carbon dioxide absorption tower, respectively. The first liquid outlet is located above the first liquid inlet, and the first liquid inlet is located above the flue gas inlet of the carbon dioxide absorption tower, so as to cool the lean liquid in the absorption tower.

9. The carbon capture and waste heat recovery system according to claim 1 or 2, characterized in that, The carbon capture waste heat recovery system also includes a scrubbing liquid cooler, which has a flue gas inlet and a flue gas outlet that are respectively connected to the top of the carbon dioxide absorption tower, so that the flue gas is cooled by passing through the scrubbing liquid cooler.

10. The carbon capture waste heat recovery system according to claim 1 or 2, characterized in that, The carbon capture waste heat recovery system also includes a gas-liquid separator. The desorption tower is equipped with a gas outlet, which is connected to the inlet of the gas-liquid separator.

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