Carbon capture system based on multi-stage pressure gradient flashing

Abstract

The application discloses a carbon capture system based on multi-stage pressure gradient flashing, which comprises an absorption tower, a regeneration tower, a lean-liquid and rich-liquid heat exchange assembly and a flashing device. The lean-liquid and rich-liquid heat exchange assembly is provided with a cold-side flow channel and a hot-side flow channel. The cold-side flow channel is communicated with a rich-liquid pipeline between the absorption tower and the regeneration tower, and the hot-side flow channel is communicated with a lean-liquid pipeline between the absorption tower and the regeneration tower. The flashing device comprises a shell, and the shell comprises a plurality of flashing chambers, a first inlet, a liquid-phase outlet and a gas-phase outlet. Liquid in the regeneration tower can enter the flashing chambers in sequence through the first inlet and be flashed, the flashed liquid phase flows to the absorption tower through the liquid-phase outlet and the lean-liquid pipeline, and the flashed gas phase flows to the regeneration tower through the gas-phase outlet. The regeneration process of the overall system is optimized in the embodiment, the absorption and regeneration efficiency is improved, the carbon capture system can be better applied to large-scale treatment of high-concentration flue gas, the absorption effect in the absorption tower is improved, and the carbon capture cost is reduced.

Description

Technical Field

[0001] This invention belongs to the field of carbon capture technology, and specifically relates to a carbon capture system based on multi-stage pressure gradient flash evaporation. Background Technology

[0002] In the field of industrial carbon capture, solvent absorption is currently the mainstream carbon capture technology. However, the high energy consumption during solvent regeneration leads to high carbon capture costs.

[0003] In related technologies, the rich liquid solvent that has absorbed carbon dioxide needs to be regenerated to release the carbon dioxide and allow the absorbent to be recycled. However, the regeneration towers in these technologies suffer from problems such as low desorption and regeneration efficiency, high energy consumption, and insufficient carbon dioxide purity, resulting in high energy consumption and low efficiency in system operation, making it difficult to meet the needs of large-scale treatment of high-concentration flue gas. Summary of the Invention

[0004] The present invention aims to at least partially solve one of the technical problems in the related art.

[0005] Therefore, embodiments of the present invention propose a carbon capture system based on multi-stage pressure gradient flash evaporation.

[0006] The carbon capture system based on multi-stage pressure gradient flash evaporation according to an embodiment of the present invention includes:

[0007] An absorption tower having a lean liquid inlet and a rich liquid outlet; A regeneration tower having a rich liquid inlet and a lean liquid outlet, a lean liquid pipeline being provided between the lean liquid outlet and the lean liquid inlet, and a rich liquid pipeline being provided between the rich liquid inlet and the rich liquid outlet; A lean-rich liquid heat exchange assembly, the lean-rich liquid heat exchange assembly having a cold-side flow channel and a hot-side flow channel, the cold-side flow channel being connected to the rich liquid pipe, and the hot-side flow channel being connected to the lean liquid pipe; A flash evaporation device, comprising a housing, the housing including multiple flash chambers, a first inlet, a liquid phase outlet and a gas phase outlet, the first inlet and the liquid phase outlet being connected to the lean liquid pipeline, and the gas phase outlet being connected to the regeneration tower; The liquid in the regeneration tower can enter the flash chamber for flash evaporation through the first inlet. The flashed liquid phase flows to the absorption tower through the liquid phase outlet and the lean liquid pipeline, and the flashed gas phase flows to the regeneration tower through the gas phase outlet.

[0008] This embodiment recovers waste heat from the lean liquor using a lean-rich liquor heat exchanger to preheat the rich liquor, significantly reducing the heating energy consumption of the regeneration tower and solving the problem of high energy consumption in solvent regeneration. This embodiment also employs a multi-stage flash evaporation device to deeply treat the regenerated lean liquor, desorbing residual carbon dioxide. This improves the purity of the lean liquor, enhances subsequent absorption efficiency, and allows the flash vapor phase to be refluxed back to the regeneration tower to recover heat and improve carbon dioxide desorption. By optimizing the overall system regeneration process, this embodiment improves desorption-regeneration efficiency and can be better applied to the large-scale treatment of high-concentration flue gas, improving absorption efficiency in the absorption tower and reducing carbon capture costs.

[0009] In some embodiments, the housing is provided with a plurality of partitions, which separate the inner cavity of the housing and form a plurality of flash chambers. The flash evaporation device further includes a pressure regulating component, which communicates with the flash chambers to regulate the pressure of the flash chambers.

[0010] In some embodiments, the pressure in the plurality of flash chambers decreases progressively along the liquid flow direction within the housing.

[0011] In some embodiments, the plurality of flash chambers are arranged sequentially from bottom to top, and in two adjacent flash chambers, the pressure of the lower flash chamber is greater than the pressure of the upper flash chamber.

[0012] In some embodiments, the first inlet is connected to the lowest flash chamber among the plurality of flash chambers, and a liquid flow channel is provided between two adjacent flash chambers so that the lean liquid can flow upward under the action of the pressure difference between the two adjacent flash chambers.

[0013] In some embodiments, the inner cavity of the housing further includes a drain chamber located at the bottom of the housing, and a downcomer is provided between the uppermost flash chamber and the drain chamber in the plurality of flash chambers, and the liquid phase outlet is connected to the drain chamber; And / or, the flash chambers are 3 to 6, some of the flash chambers have a pressure of 0.15 MPa to 0.25 MPa, some of the flash chambers have a pressure of 0.08 MPa to 0.15 MPa, and some of the flash chambers have a pressure of 0.03 MPa to 0.08 MPa; And / or, the temperature range of the liquid flowing into the flash evaporator is 80 degrees Celsius to 120 degrees Celsius; And / or, the flash evaporation device includes a plurality of riser pipes connected between two adjacent flash chambers, the inner cavity of the riser pipe being configured as the liquid flow channel, so that liquid in the lower flash chamber can flow into the upper flash chamber through the riser pipe.

[0014] In some embodiments, a wire mesh demister is also included, and a vent pipe is provided on the partition between two adjacent flash chambers. The wire mesh demister is located below the vent pipe, and a pressure control valve is provided on the vent pipe.

[0015] In some embodiments, the gas phase outlet is connected to the middle or lower part of the regeneration tower; And / or, it also includes a heat pump and a reboiler, the reboiler being connected to the regeneration tower to heat the liquid at the bottom of the regeneration tower, a gas phase reflux pipe between the gas phase outlet and the regeneration tower, and the heat pump being located on the gas phase reflux pipe and between the reboiler to recover the heat of the gas phase in the gas phase reflux pipe and transfer the heat to the liquid flowing from the regeneration tower into the reboiler.

[0016] In some embodiments, a control system is also included, which is connected to the flash evaporator to adjust the pressure of different flash chambers in the flash evaporator.

[0017] In some embodiments, the lean liquid pipeline between the lean liquid outlet and the lean-rich liquid heat exchange assembly includes a first branch pipeline and a second branch pipeline. The first inlet and the liquid phase outlet of the flash evaporator are connected to the first branch pipeline. The first end of the second branch pipeline is connected to the bottom of the regeneration tower, and the second end of the second branch pipeline is connected to the lean-rich liquid heat exchange assembly. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a carbon capture system based on multi-stage pressure gradient flash evaporation according to an embodiment of the present invention.

[0019] Figure 2 This is a schematic diagram of the flash evaporation device according to an embodiment of the present invention.

[0020] Figure label: 1. Absorption tower; 2. Regeneration tower; 3. Heat exchanger assembly for liquids of varying strengths and deficiencies; 41. Lean solution pipeline; 411. First branch pipeline; 412. Second branch pipeline; 42. Rich solution pipeline; 5. Flash evaporator; 51. Shell; 52. Flash chamber; 53. First inlet; 54. Liquid phase outlet; 55. Gas phase outlet; 56. Baffle; 57. Drainage chamber; 581. Downcomer; 582. Riser; 583. Vent pipe; 584. Pressure control valve; 59. Wire mesh demister; 6. Heat pump; 61. Evaporator; 62. Condenser; 7. Reboiler; 8. Control system. Detailed Implementation

[0021] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0022] See Figure 1 and Figure 2 The carbon capture system based on multi-stage pressure gradient flash evaporation according to an embodiment of the present invention includes an absorption tower 1, a regeneration tower 2, a lean and rich liquor heat exchange assembly 3, and a flash evaporation device 5. The absorption tower 1 has a lean liquor inlet and a rich liquor outlet.

[0023] The regeneration tower 2 has a rich liquid inlet and a lean liquid outlet. A lean liquid pipe 41 is provided between the lean liquid outlet and the lean liquid inlet, and a rich liquid pipe 42 is provided between the rich liquid inlet and the rich liquid outlet. The lean-rich liquid heat exchange assembly 3 has a cold side flow channel and a hot side flow channel. The cold side flow channel is connected to the rich liquid pipe 42, and the hot side flow channel is connected to the lean liquid pipe 41. In this embodiment, the absorption tower 1 receives lean liquid (regenerated absorbent) through the lean liquid inlet. The lean liquid absorbs carbon dioxide from the flue gas in the absorption tower 1 to form rich liquid. The rich liquid is transported to the regeneration tower 2 through the rich liquid outlet and the rich liquid pipe 42. In the lean-rich liquid heat exchange assembly 3, the rich liquid flows through the cold side flow channel, and the high-temperature lean liquid discharged from the regeneration tower 2 flows through the hot side flow channel. The two exchange heat, the rich liquid is preheated, reducing the energy consumption required for the regeneration tower 2 to heat the rich liquid, and the lean liquid is initially cooled, thereby improving the carbon dioxide capture effect in the absorption tower 1.

[0024] The flash evaporation unit 5 includes a shell 51, which includes multiple flash chambers 52, a first inlet 53, a liquid outlet 54, and a gas outlet 55. The first inlet 53 and the liquid outlet 54 are connected to the lean liquid pipeline 41, and the gas outlet 55 is connected to the regeneration tower 2. The liquid in the regeneration tower 2 can enter the flash chambers 52 sequentially through the first inlet 53 for flash evaporation. The flashed liquid phase flows to the absorption tower 1 through the liquid outlet 54 and the lean liquid pipeline 41, and the flashed gas phase flows to the regeneration tower 2 through the gas outlet 55.

[0025] The regeneration tower 2 desorbs and regenerates the preheated rich liquid, releasing carbon dioxide. The regenerated liquid can be transported to the flash evaporator 5 through the lean liquid outlet and lean liquid pipeline 41. The liquid flowing into the flash evaporator 5 can be lean liquid, or rich liquid that has not been fully desorbed, or some of the rich liquid can be directly transported to the first inlet 53.

[0026] In this embodiment, the lean liquor enters the flash evaporator 5 through the first inlet 53 and sequentially passes through multiple flash chambers 52 for flash evaporation. During the flash evaporation process, a small amount of residual carbon dioxide in the lean liquor is desorbed to form a gas phase. The liquid phase (lean liquor) after flash evaporation flows to the absorption tower 1 for recycling after passing through the liquid phase outlet 54, the lean liquor pipeline 41, and the lean-rich liquor heat exchange assembly 3. The gas phase (containing carbon dioxide) after flash evaporation flows back to the regeneration tower 2 through the gas phase outlet 55. The heat in the gas phase can supplement the heat of the regeneration tower 2 and can also be used as booster steam.

[0027] In this embodiment, the waste heat of the lean liquor is recovered by the lean-rich liquor heat exchange component 3 to preheat the rich liquor, which can significantly reduce the heating energy consumption of the regeneration tower 2 and solve the problem of high energy consumption in solvent regeneration. In this embodiment, the regenerated lean liquor is further treated by a multi-stage flash evaporation device 5 to desorb residual carbon dioxide, thereby improving the purity of the lean liquor and increasing the subsequent absorption efficiency. At the same time, the flash vapor phase can be refluxed to the regeneration tower 2 to recover heat and improve the desorption effect of carbon dioxide.

[0028] This embodiment optimizes the regeneration process of the overall system, improves the desorption and regeneration efficiency, and can be better applied to the large-scale treatment of high-concentration flue gas, thereby improving the absorption effect in the absorption tower and reducing carbon capture costs.

[0029] In some embodiments, the housing 51 is provided with a plurality of partitions 56, which separate the inner cavity of the housing 51 and form a plurality of flash chambers 52. The flash evaporation device 5 also includes a pressure regulating component, which is connected to the flash chambers 52 to regulate the pressure of the flash chambers 52.

[0030] In this embodiment, there can be 2, 3, or 5 partitions, which can divide the inner cavity of the shell 51 into multiple relatively independent chambers. The pressure of each flash chamber 52 can be independently adjusted and controlled. The pressure adjustment component can be (such as a pressure reducing valve, vacuum pump, etc.) connected to each flash chamber 52. During application, the pressure of each flash chamber 52 can be precisely adjusted according to process requirements to provide a suitable pressure environment for lean liquor flash evaporation and ensure that the residual carbon dioxide in the lean liquor can be fully desorbed.

[0031] The independent flash chamber 52 in this embodiment can avoid mutual pressure interference between the flash chambers 52, ensuring the stability of the flash evaporation process; the pressure regulating component can flexibly adjust the pressure of each flash chamber 52 to adapt to the flash evaporation requirements of different concentrations of lean solution, improve flash evaporation efficiency, ensure that residual carbon dioxide in the lean solution is fully desorbed, further improve the purity of the lean solution and the carbon dioxide recovery rate, realize the design of multi-stage pressure gradient, and improve the flash evaporation effect.

[0032] In some embodiments, the pressure in the plurality of flash chambers 52 decreases stepwise along the liquid flow direction within the housing 51.

[0033] In this embodiment, after the lean liquid is discharged from the regeneration tower 2, it can sequentially enter multiple flash chambers 52 along a preset flow direction, with the pressure in each flash chamber 52 decreasing gradually. The multiple flash chambers 52 can be designed in a multi-stage gradient pattern of high pressure, medium pressure, and low pressure. The lean liquid undergoes flash vaporization in the high-pressure flash chamber 52, medium-pressure flash chamber 52, and low-pressure flash chamber 52, thereby avoiding the violent vaporization caused by a single flash evaporation, allowing dissolved gases to be released step by step, improving the separation effect, and reducing the impact on subsequent pipelines. This avoids problems such as water hammer, vibration, and poor drainage, achieving a stepped deep flash evaporation.

[0034] The multi-stage pressure gradient design in this embodiment can solve the problem of low desorption efficiency in regeneration tower 2. The gradient pressure can avoid problems such as lean liquid splashing and gas phase entrainment caused by one-time pressure reduction, ensuring a stable flash evaporation process, while reducing energy consumption and further reducing carbon capture costs.

[0035] Furthermore, multiple flash chambers 52 are arranged sequentially from bottom to top, and in two adjacent flash chambers 52, the pressure of the lower flash chamber 52 is greater than the pressure of the upper flash chamber 52.

[0036] In this embodiment, multiple flash chambers 52 are arranged vertically from bottom to top, with the lower flash chamber 52 having a higher pressure than the upper flash chamber 52, forming a pressure gradient from bottom to top. The lean liquid discharged from the regeneration tower 2 enters from the lowest flash chamber 52. Under the action of the pressure difference, the lean liquid can automatically flow upward and pass through each flash chamber 52 in sequence to complete the stepped flash evaporation, without the need for additional conveying equipment.

[0037] The vertically arranged pressure gradient design in this embodiment utilizes pressure difference to achieve automatic flow of the lean solution. Simultaneously, by leveraging the pressure difference and vertical height difference, it balances the stability of the liquid, avoiding problems such as violent splashing, reducing the investment and operating energy consumption of conveying equipment, lowering system energy consumption, and improving stability. The vertical arrangement of the flash chamber 52 also saves floor space, adapting to the site requirements of large-scale production, increasing integration, improving space utilization, allowing for more concentrated equipment layout, reducing pipeline length, and ensuring sufficient desorption of carbon dioxide from the lean solution through stepped flash evaporation, improving lean solution purity and carbon dioxide recovery rate, and optimizing system operating efficiency.

[0038] In some embodiments, the first inlet 53 is connected to the lowest flash chamber 52 among a plurality of flash chambers 52, and a liquid flow channel is provided between two adjacent flash chambers 52 so that the lean liquid can flow upward under the action of the pressure difference between the two adjacent flash chambers 52.

[0039] In this embodiment, the first inlet 53 is connected to the lowest flash chamber 52. The lean liquid discharged from the regeneration tower 2 directly enters the lowest high-pressure flash chamber 52. After the initial flash evaporation is completed, under the pressure difference between adjacent flash chambers 52, it flows upward into the upper low-pressure flash chamber 52 through the liquid flow channel, and the flash evaporation treatment of each flash chamber 52 is completed in sequence. The liquid flow channel provides guidance for the flow of lean liquid, ensuring that the lean liquid flows smoothly and avoiding leakage or poor flow.

[0040] In this embodiment, the inflow path and flow pattern of the lean liquid are clearly defined. Pressure and height differences can be used to achieve automatic upward flow of the lean liquid and balance its stability, eliminating the need for additional transport power and reducing energy consumption. The liquid flow channel ensures smooth flow of the lean liquid, preventing localized stagnation and improving flash evaporation efficiency. The structural design of this embodiment is simple, easy to process and maintain, and suitable for the long-term stable operation of large-scale systems.

[0041] Optionally, the flash evaporation device 5 includes a plurality of riser pipes 582, which are connected between two adjacent flash chambers 52. The inner cavity of the riser pipe 582 is configured as the liquid flow channel, and the liquid in the lower flash chamber 52 can flow into the upper flash chamber 52 through the riser pipe 582.

[0042] In this embodiment, the first inlet 53 is connected to the lowest flash chamber 52. The lean liquid discharged from the regeneration tower 2 directly enters the lowest high-pressure flash chamber 52. After the initial flash evaporation is completed, under the pressure difference between the adjacent flash chambers 52, it flows upward into the upper low-pressure flash chamber 52 through the riser pipe 582, and the flash evaporation treatment of each flash chamber 52 is completed in sequence.

[0043] The riser pipe 582 guides the flow of lean liquid, using the pressure difference between the upper and lower flash chambers 52 as a driving force to propel the lean liquid upwards, ensuring stable flow and preventing leakage or obstruction. The riser pipe 582 is structurally compatible with vertically arranged flash chambers 52, facilitating directional flow of the lean liquid, preventing localized stagnation, and improving flash evaporation efficiency. The riser pipe 582 in this embodiment features a simple design, is easy to manufacture and maintain, and can further optimize the flash evaporation effect of multi-stage pressure gradients, ensuring complete desorption of carbon dioxide from the lean liquid.

[0044] Furthermore, the inner cavity of the shell 51 also includes a drain chamber 57, which is located at the bottom of the shell 51. A downcomer is provided between the uppermost flash chamber 52 and the drain chamber 57, and the liquid phase outlet 54 is connected to the drain chamber 57.

[0045] In this embodiment, the drain chamber 57 is located at the bottom of the shell 51. The liquid phase (lean liquid) after flash evaporation in the uppermost flash chamber 52 flows into the drain chamber 57 through the downcomer. The drain chamber 57 collects the lean liquid and then transports it to the lean liquid pipeline 41 through the liquid phase outlet 54, flowing towards the absorption tower 1. The downcomer in this embodiment can ensure a stable flow of lean liquid into the drain chamber 57, reduce lean liquid splashing and gas phase entrainment, and ensure the purity of the lean liquid.

[0046] In this embodiment, there are 3 to 6 flash chambers 52, with some flash chambers having a pressure of 0.15 MPa to 0.25 MPa, some flash chambers having a pressure of 0.08 MPa to 0.15 MPa, and some flash chambers having a pressure of 0.03 MPa to 0.08 MPa.

[0047] At least three flash chambers 52 form a multi-stage pressure gradient, achieving deep desorption of carbon dioxide from the lean solution and ensuring thorough desorption. The drain chamber 57 enables the centralized collection of the lean solution after flash evaporation, avoiding poor transport caused by the dispersed flow of the lean solution and improving the lean solution transport efficiency.

[0048] For example, the pressure in the middle flash chamber is 0.08 MPa to 0.15 MPa, and the pressure in the uppermost flash chamber is 0.03 MPa to 0.08 MPa. This allows for staged flash evaporation of the fluid.

[0049] This embodiment optimizes the internal space of the shell 51 to ensure stable and efficient flow of lean liquid, avoiding dead zones or high flow resistance, thereby improving the efficiency, stability, and reliability of flash evaporation.

[0050] Optionally, the temperature range of the liquid flowing into the flash evaporator is 80 degrees Celsius to 120 degrees Celsius. This embodiment can be combined with a multi-stage flash evaporation chamber to achieve efficient flash evaporation of the liquid, thereby optimizing the carbon dioxide load from 0.2 mol / mol to 0.05 mol / mol.

[0051] In some embodiments, the flash evaporation device 5 further includes a wire mesh demister 59, and a vent pipe 583 is provided on the partition 56 between two adjacent flash evaporation chambers 52. The wire mesh demister 59 is located below the vent pipe 583, and a pressure control valve 584 is provided on the vent pipe 583.

[0052] In this embodiment, the vent pipe 583 between adjacent flash chambers 52 is used to connect the gas phase of each flash chamber 52, allowing the gas phase generated by flashing to flow smoothly upwards and eventually return to the regeneration tower 2 through the gas phase outlet 55. A wire mesh demister 59 is located below the vent pipe 583. When the lean liquid flashes to generate the gas phase, a small amount of lean liquid droplets may be entrained in the gas phase. The wire mesh demister 59 can intercept these droplets, causing them to fall back into the lean liquid in the flash chamber 52, preventing the lean liquid from being lost with the gas phase.

[0053] Optionally, under pressure, the liquid in the upper flash chamber 52 will not flow through the vent pipe 583 into the lower flash chamber 52. The channels in the vent pipe 583 can be arranged with micropores side by side, which can prevent the liquid from flowing downward and ensure that the gas can flow upward.

[0054] The wire mesh demister 59 in this embodiment can effectively intercept lean liquid droplets in the gas phase, reduce absorbent loss, lower operating costs, prevent lean liquid droplets from re-entering the regeneration tower 2, ensure stable desorption efficiency of the regeneration tower 2, and improve the purity of the reflux gas phase. The wire mesh demister can also level the liquid phase in the flash chamber 52 below, preventing violent turbulence or splashing of the liquid phase.

[0055] In some embodiments, the gas phase outlet 55 is connected to the middle or lower part of the regeneration tower 2.

[0056] In this embodiment, the gas phase outlet 55 is connected to the middle or lower part of the regeneration tower 2. The gas phase (containing carbon dioxide) generated by flash evaporation flows back to the middle or lower part of the regeneration tower 2, which can replenish the heat in the regeneration tower 2, contact the rich liquid in the regeneration tower 2, further desorb the carbon dioxide in the rich liquid, improve the carbon dioxide purity and regeneration efficiency, and at the same time, it can be used as booster steam to improve the carbon dioxide desorption effect.

[0057] In some embodiments, the carbon capture system based on multi-stage pressure gradient flash evaporation further includes a heat pump 6 and a reboiler 7. The reboiler 7 is connected to the regeneration tower 2 to heat the liquid at the bottom of the regeneration tower 2. A gas phase reflux pipe is provided between the gas phase outlet 55 and the regeneration tower 2. The heat pump 6 is located on the gas phase reflux pipe and between the reboiler 7 to recover the heat of the gas phase in the gas phase reflux pipe and exchange the heat with the liquid flowing from the regeneration tower 2 into the reboiler 7.

[0058] In this embodiment, the reboiler 7 can be used to heat the liquid at the bottom of the regeneration tower 2, providing heat for the rich liquid desorption. When the gas phase generated by flash evaporation flows through the gas phase reflux pipe, the heat pump 6 recovers the heat in the gas phase and transfers it to the liquid flowing into the reboiler 7, realizing the recovery and reuse of heat.

[0059] The heat pump 6 may include an evaporator 61 and a condenser 62. The evaporator 61 is connected to a gas phase reflux pipe, and the condenser 62 is connected to the pipes at the inlet of the regeneration tower 2 and the reboiler 7. A compressor is installed between the evaporator 61 and the condenser 62. The compressor can compress the heat-exchanged working fluid and then deliver it to the condenser 62. The condenser 62 uses the heat of the working fluid to transfer to the rich liquid in the pipe between the inlet of the regeneration tower 2 and the reboiler 7, thereby reducing the energy consumption of the regeneration tower 2.

[0060] In this embodiment, heat pump 6 recovers waste heat from the gas phase to provide some heat to reboiler 7, reducing the external heat source requirement of reboiler 7, further reducing system energy consumption, alleviating the pain point of high energy consumption in rich liquid regeneration, and at the same time achieving the requirement of efficient carbon capture.

[0061] In some embodiments, the carbon capture system based on multi-stage pressure gradient flash evaporation further includes a control system 8, which is connected to the flash evaporation device 5 to adjust the pressure of different flash chambers 52 in the flash evaporation device 5.

[0062] The control system 8 in this embodiment can be connected to the pressure regulating component of the flash evaporation device 5. Through a preset program and pressure data fed back from sensors, it adjusts the pressure of each flash chamber 52 in real time, keeping the pressure of each flash chamber 52 within a preset gradient range. At the same time, the control system 8 can flexibly adjust the pressure gradient according to changes in operating conditions such as flue gas concentration and rich liquid flow rate, ensuring stable flash evaporation efficiency and desorption effect.

[0063] This embodiment can achieve automated and precise adjustment of the pressure of the flash evaporator 5, reduce manual operation, reduce human error, ensure the stability of multi-level pressure gradient, improve flash evaporation efficiency and system operation stability. This embodiment can flexibly adapt to different working conditions, avoid fluctuations in working conditions, optimize the flash evaporation conditions of the flash evaporator 5, thereby improving the system's adaptability and large-scale operation capability.

[0064] In some embodiments, the lean liquid pipeline 41 between the lean liquid outlet and the lean-rich liquid heat exchange assembly 3 includes a first branch pipeline 411 and a second branch pipeline 412. The first inlet 53 and the liquid phase outlet 54 of the flash evaporator 5 are connected to the first branch pipeline 411. The first end of the second branch pipeline 412 is connected to the bottom of the regeneration tower 2, and the second end of the second branch pipeline 412 is connected to the lean-rich liquid heat exchange assembly 3.

[0065] In this embodiment, the lean liquid discharged from the regeneration tower 2 can be divided into two paths. One path enters the flash evaporator 5 through the first branch pipe 411, completes the flash evaporation treatment, returns to the first branch pipe 411 through the liquid phase outlet 54, and flows to the lean-rich liquid heat exchange assembly 3. The other path flows directly to the lean-rich liquid heat exchange assembly 3 through the second branch pipe 412. The second branch pipe 412 can merge with the lean liquid from the first branch pipe 411, which is connected to the liquid phase outlet 54 of the flash evaporator 5, and after joint heat exchange and cooling, enter the absorption tower 1.

[0066] The lean liquor in the second branch pipe 412 originates from the bottom of the regeneration tower 2 and is at a higher temperature, further providing heat to the lean-rich liquor heat exchange assembly 3. This dual-branch pipe design allows for flexible adjustment of the lean liquor flow rate into the flash evaporator 5, adapting to different flash evaporation requirements. The high-temperature lean liquor in the second branch pipe 412 supplements the heat of the lean-rich liquor heat exchange assembly 3, further enhancing the preheating effect of the rich liquor and reducing the energy consumption of the regeneration tower 2. This embodiment also prevents the entire system from being affected by a failure of the flash evaporator 5, improving the reliability and stability of the system and ensuring continuous and stable large-scale production.

[0067] This embodiment can artificially create a multi-stage unbalanced state by setting up multiple flash chambers 52 with progressively decreasing pressure, thereby forcing the segmented desorption of carbon dioxide, breaking the balance limitation of single-stage flash evaporation, and improving the overall removal rate. This embodiment can also realize the cascade utilization of thermal energy. As the flash evaporation process is accompanied by a decrease in temperature, the system can achieve energy recycling by recovering the latent heat and sensible heat of the flash gas, significantly reducing regeneration energy consumption.

[0068] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0069] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0070] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0071] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0072] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0073] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A carbon capture system based on multi-stage pressure gradient flash evaporation, characterized in that, include: An absorption tower having a lean liquid inlet and a rich liquid outlet; A regeneration tower having a rich liquid inlet and a lean liquid outlet, a lean liquid pipeline being provided between the lean liquid outlet and the lean liquid inlet, and a rich liquid pipeline being provided between the rich liquid inlet and the rich liquid outlet; A lean-rich liquid heat exchange assembly, the lean-rich liquid heat exchange assembly having a cold-side flow channel and a hot-side flow channel, the cold-side flow channel being connected to the rich liquid pipe, and the hot-side flow channel being connected to the lean liquid pipe; A flash evaporation device, comprising a housing, the housing including multiple flash chambers, a first inlet, a liquid phase outlet and a gas phase outlet, the first inlet and the liquid phase outlet being connected to the lean liquid pipeline, and the gas phase outlet being connected to the regeneration tower; The liquid in the regeneration tower can enter the flash chamber for flash evaporation through the first inlet. The flashed liquid phase flows to the absorption tower through the liquid phase outlet and the lean liquid pipeline, and the flashed gas phase flows to the regeneration tower through the gas phase outlet.

2. The carbon capture system based on multi-stage pressure gradient flash evaporation according to claim 1, characterized in that, The housing is provided with multiple partitions, which separate the inner cavity of the housing and form multiple flash chambers. The flash evaporation device also includes a pressure regulating component, which is connected to the flash chamber to regulate the pressure of the flash chamber.

3. The carbon capture system based on multi-stage pressure gradient flash evaporation according to claim 2, characterized in that, The pressure in the multiple flash chambers decreases progressively along the liquid flow direction within the shell.

4. The carbon capture system based on multi-stage pressure gradient flash evaporation according to claim 2, characterized in that, The multiple flash chambers are arranged sequentially from bottom to top, and in two adjacent flash chambers, the pressure of the lower flash chamber is greater than the pressure of the upper flash chamber.

5. The carbon capture system based on multi-stage pressure gradient flash evaporation according to claim 4, characterized in that, The first inlet is connected to the lowest flash chamber among the plurality of flash chambers, and a liquid flow channel is provided between two adjacent flash chambers so that the lean liquid can flow upward under the action of the pressure difference between the two adjacent flash chambers.

6. The carbon capture system based on multi-stage pressure gradient flash evaporation according to claim 5, characterized in that, The inner cavity of the shell also includes a drain chamber, which is located at the bottom of the shell. A downcomer is provided between the uppermost flash chamber and the drain chamber among the plurality of flash chambers, and the liquid phase outlet is connected to the drain chamber. And / or, the flash chambers are 3 to 6, some of the flash chambers have a pressure of 0.15 MPa to 0.25 MPa, some of the flash chambers have a pressure of 0.08 MPa to 0.15 MPa, and some of the flash chambers have a pressure of 0.03 MPa to 0.08 MPa; And / or, the temperature range of the liquid flowing into the flash evaporator is 80 degrees Celsius to 120 degrees Celsius; And / or, the flash evaporation device includes a plurality of riser pipes connected between two adjacent flash chambers, the inner cavity of the riser pipe being configured as the liquid flow channel, so that liquid in the lower flash chamber can flow into the upper flash chamber through the riser pipe.

7. The carbon capture system based on multi-stage pressure gradient flash evaporation according to claim 4, characterized in that, It also includes a wire mesh demister, and a vent pipe is provided on the partition between two adjacent flash chambers. The wire mesh demister is located below the vent pipe, and a pressure control valve is provided on the vent pipe.

8. The carbon capture system based on multi-stage pressure gradient flash evaporation according to any one of claims 1 to 7, characterized in that, The gas phase outlet is connected to the middle or lower part of the regeneration tower; And / or, it also includes a heat pump and a reboiler, the reboiler being connected to the regeneration tower to heat the liquid at the bottom of the regeneration tower, a gas phase reflux pipe between the gas phase outlet and the regeneration tower, and the heat pump being located on the gas phase reflux pipe and between the reboiler to recover the heat of the gas phase in the gas phase reflux pipe and transfer the heat to the liquid flowing from the regeneration tower into the reboiler.

9. The carbon capture system based on multi-stage pressure gradient flash evaporation according to any one of claims 1 to 7, characterized in that, It also includes a control system connected to the flash evaporator to adjust the pressure of different flash chambers in the flash evaporator.

10. The carbon capture system based on multi-stage pressure gradient flash evaporation according to any one of claims 1 to 7, characterized in that, The lean liquid pipeline between the lean liquid outlet and the lean-rich liquid heat exchange assembly includes a first branch pipeline and a second branch pipeline. The first inlet and the liquid phase outlet of the flash evaporator are connected to the first branch pipeline. The first end of the second branch pipeline is connected to the bottom of the regeneration tower, and the second end of the second branch pipeline is connected to the lean-rich liquid heat exchange assembly.

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