Carbon capture device and method

Abstract

The invention discloses a carbon capture device and method, which are used for integrating CO2 absorption and desorption processes of carbon capture in the same device, the device at least comprises: an absorption unit arranged at the upper part of the device; in the absorption unit, the absorption slurry is in contact with carbon-containing gas from top to bottom so as to carry out gas-liquid mass transfer under a high-pressure condition; the solid phase part of the absorption slurry is powder of a supported ionic liquid, and the ionic liquid is an amino-containing ionic liquid; the desorption unit is arranged below the absorption unit and is isolated by a liquid seal; under the vacuum condition, the absorbed slurry is subjected to CO2 desorption in a desorption unit, the desorbed slurry is recycled after being subjected to gas-liquid separation, and CO2 is discharged. According to the invention, the gas-liquid mass transfer efficiency can be effectively improved and the absorption rate of CO2 can be increased through the nano-micro interface strengthening effect; absorption and desorption are integrated into the whole device, different areas are isolated in a liquid sealing mode, and the functions of high-pressure absorption and vacuum desorption can be achieved in the same device.

Description

Carbon capture devices and methods Technical Field

[0001] This invention relates to the field of carbon capture technology, and in particular to a carbon capture device and method with enhanced nano-micro interface. Background Technology

[0002] The excessive use of fossil fuels has led to the generation of large amounts of greenhouse gases, especially excessive emissions of CO2. Currently, the atmospheric CO2 concentration has reached 0.0182 mol / m³. 3 Compared to 0.0125 mol / m before the Industrial Revolution 3 There has been a significant improvement. Therefore, efficient CO2 capture and separation is an urgent priority for solving the environmental crisis and developing renewable energy.

[0003] Currently, the organic amine method is the most commonly used separation technique. Taking monoethanolamine as an example, CO2 can react with it to form the corresponding water-soluble salt, and heating it can release CO2, thereby achieving CO2 capture and enrichment. However, the amine absorption method also has significant drawbacks. First, amine solvents such as MEA have poor stability, especially prone to decomposition in the presence of oxygen or other impurities. Second, the separation unit needs to reduce the concentration of sulfur oxides and carbon oxides in the combustion exhaust gas to 1 mL / m³. 3 The solvent must be of a certain grade; otherwise, it will react with the absorbent solvent and deteriorate rapidly. Furthermore, such solvents are corrosive, requiring expensive equipment; regeneration requires higher temperatures, resulting in additional energy consumption.

[0004] Physical absorption utilizes the differences in solubility of gases in a gas mixture within a physical solvent to achieve absorption and separation. Under specific conditions, such as the properties of the solute and solvent, and factors like system temperature, pressure, and concentration, the equilibrium vapor pressure of the dissolved gases exhibits different behaviors. The physical absorption process is primarily driven by the difference in CO2 partial pressure between the gas and liquid phases. When CO2 passes through the absorption section and is absorbed by the lean liquid, transforming it into a rich liquid, the device used is called an absorber; when the rich liquid desorbs CO2 through separation or regeneration, the equipment used is called a regenerator. This technology, through continuous solution replenishment, can form a cycle, allowing the absorbent to be continuously desorbed and reused multiple times. Furthermore, physical absorption methods achieve optimal performance at low temperatures and high pressures. The absorption and desorption processes of physical absorption are relatively simple, with a single operation, resulting in lower operating costs, lower energy consumption, and less equipment corrosion.

[0005] For example, Korean Patent KR102634991B1 discloses a carbon dioxide capture system using ionic liquids. This system expands the heat transfer area between the flue gas and the ionic liquid generated in industrial processes, enabling effective temperature control of the ionic liquid with minimal energy consumption. This allows for efficient cooling of the ionic liquid while using a small amount of it, and the system stores carbon dioxide after regenerating the ionic liquid by selectively absorbing carbon dioxide using the waste heat from high-temperature waste gas. This method uses ionic liquids to absorb CO2 via physical absorption. However, this type of physical absorption method suffers from low mass transfer efficiency between CO2 molecules and the liquid, resulting in a slow absorption rate and consequently low carbon capture efficiency. Furthermore, the CO2 absorption and desorption processes are conducted in separate reactors under significantly different operating conditions, leading to substantial equipment investment.

[0006] Therefore, there is an urgent need for a carbon capture device and method that can not only effectively improve gas-liquid mass transfer efficiency, thereby improving the CO2 absorption efficiency of carbon capture, but also complete the absorption and desorption processes in the same reactor, effectively reducing equipment investment while ensuring the cyclic absorption effect.

[0007] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0008] The purpose of this invention is to provide a carbon capture device and method with enhanced nano-micro interface. The absorbent system consists of a solid phase and a liquid phase, with the solid phase being a powder of supported ionic liquid and the liquid phase being an ionic liquid containing amine groups. This can effectively improve gas-liquid mass transfer efficiency and increase the CO2 absorption rate.

[0009] Another objective of this invention is to provide a carbon capture device and method with enhanced nano-micro interface, which integrates absorption and desorption into a single device and isolates different areas by using a liquid seal, thereby achieving the functions of high-pressure absorption and vacuum desorption in the same device.

[0010] To achieve the above objectives, according to a first aspect of the present invention, a carbon capture device is provided for integrating the CO2 absorption and desorption processes of carbon capture into the same device, comprising at least: an absorption unit disposed at the upper part of the device; in the absorption unit, an absorption slurry is contacted from top to bottom with a carbon-containing gas from bottom to top, performing gas-liquid mass transfer under high pressure; the solid phase of the absorption slurry is a powder of a supported ionic liquid, the ionic liquid being an ionic liquid containing amine groups; a desorption unit disposed below the absorption unit and isolated by a liquid seal; under vacuum conditions, the absorbed slurry undergoes CO2 desorption in the desorption unit, and the desorbed slurry is recycled after gas-liquid separation, with CO2 discharged externally.

[0011] Furthermore, in the above technical solution, the absorption unit is preferably a packed tower structure, with a liquid distributor at the top, a gas distributor at the bottom, and packing material in the middle; a cone-shaped liquid seal structure is provided below the gas distributor to receive the absorbed slurry and maintain a certain liquid level.

[0012] Furthermore, in the above technical solution, the desorption unit can be set in multiple stages; the diameter of the first-stage desorption unit is larger than the diameter of the absorption unit, and the diameter of the multi-stage desorption units increases progressively.

[0013] Furthermore, in the above technical solution, the solid content of the absorbent slurry is preferably 0.5-30% by weight; the ionic liquid is preferably one or more of [APMIm][Br], [Hmim][NTf2], [BMIm][Ac], and the carrier can be one or more of alumina, silica gel, titanium dioxide, activated carbon, and molecular sieve; the loading of the ionic liquid is preferably 2-50%; and the liquid phase of the absorbent slurry can be one or more of water and alcohol systems.

[0014] Furthermore, in the above technical solution, the packing material of the absorption unit can be one or more of the following: annular, saddle-shaped, and corrugated.

[0015] Furthermore, in the above technical solution, a liquid level regulating unit can be provided at a corresponding position of the conical liquid seal structure to isolate the pressure operating range between the absorption unit and the multi-stage desorption unit and to control the circulation rate of the slurry. The liquid level regulating unit may include: a regulating valve, which is located at the bottom of the conical liquid seal structure; a differential pressure level gauge, which is interlocked with the regulating valve to control the liquid seal height of adjacent units and maintain the required pressure range, and to control the circulation rate of the slurry.

[0016] Furthermore, in the above technical solution, the desorption unit is preferably set in two stages; wherein, the first stage desorption unit can be a plate tower structure, and the plate tower is preferably arranged in an alternating manner and has an overflow weir, which is used to extend the residence time of the slurry to be desorbed in the plate tower.

[0017] Furthermore, in the above technical solution, gas discharge pipelines can be installed at the top of the primary desorption unit and between the trays to discharge the desorbed CO2 in a timely manner, and the slurry after gas-liquid separation can be recycled.

[0018] Furthermore, in the above technical solution, the secondary desorption unit can be a tank-type structure, and preferably, a stirring blade is provided inside the tank-type structure, which can further desorb CO2 under a higher vacuum degree than the primary desorption unit.

[0019] Furthermore, in the above technical solution, a gas discharge pipeline is installed at the top of the secondary desorption unit to discharge the desorbed CO2 in a timely manner, and the slurry after gas-liquid separation can be recycled.

[0020] Furthermore, in the above technical solution, the slurry desorbed in the secondary desorption unit can be pumped by a slurry circulation pump to the liquid distributor in the absorption unit for recycling.

[0021] Furthermore, in the above technical solution, the top of the absorption unit is equipped with a tower top mixing gas pipeline. After gas-liquid separation, the decarbonized gas is discharged, and the liquid can be returned to the liquid distributor for recycling.

[0022] According to a second aspect of the present invention, the present invention provides a carbon capture method, using the aforementioned apparatus, comprising at least the following steps: A. CO2 absorption process: In the absorption unit, the absorption slurry is countercurrently contacted with carbon-containing gas from top to bottom, and gas-liquid mass transfer is performed under high pressure. The irregular movement of solid particles in the slurry is used to suppress the coalescence of bubbles during the gas-liquid mass transfer process. The solid particles in the slurry use ionic liquids containing amine functional groups as the centers for CO2 adsorption, adsorbing CO2 from the gas phase and then passing through the gas-liquid interface to transport CO2 to the liquid phase for absorption; B. A portion of the absorbed slurry forms a liquid seal at the bottom of the absorption unit. The liquid seal controls the required pressure and slurry circulation rate in the absorption unit and the primary desorption unit through interlocking; C. CO2 desorption process: Another portion of the absorbed slurry enters the primary desorption unit and performs primary CO2 desorption under vacuum. The desorbed slurry is recycled.

[0023] Furthermore, in the above technical solution, step C may also include a secondary desorption process, with primary desorption and secondary desorption separated by a liquid seal, and the secondary desorption preferably having a higher vacuum degree than the primary desorption.

[0024] Furthermore, in the above technical solution, the residence time of the slurry can be extended during the primary desorption process by using staggered tower plates and overflow weir structures; the slurry can be stirred during the secondary desorption process.

[0025] Furthermore, in the above technical solution, the slurry after primary desorption and / or secondary desorption is returned to the absorption unit for recycling, and the desorbed CO2 is discharged.

[0026] Furthermore, in the above technical solution, the decarbonized gas obtained in the CO2 absorption process is discharged after gas-liquid separation, and the separated liquid is recycled as absorption slurry.

[0027] Furthermore, in the above technical solution, the operating temperature of the CO2 absorption process can be 5 to 50°C; the operating pressure can be 0 to 2 MPa; and the liquid-to-gas volume ratio can be 0.1 to 2.

[0028] Furthermore, in the above technical solution, the operating temperature of the first-stage desorption process can be 5 to 50°C, and the operating pressure can be -50 to 0 kPa; the operating temperature of the second-stage desorption process can be 5 to 50°C, and the operating pressure can be -150 to -80 kPa.

[0029] Furthermore, in the above technical solution, the CO2 concentration of the carbon-containing gas can range from 10% to 80%.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1) This invention constructs an absorbent system with nano-micro interface enhancement function, using a supported ionic liquid as the solid phase and a solvent as the liquid phase. Through a matching process, the nano-micro interface enhancement effect is utilized to effectively improve gas-liquid mass transfer efficiency and increase the CO2 absorption rate. Specifically, the absorbent system with nano-micro interface enhancement function can utilize the irregular movement of solid particles in the slurry to inhibit bubble coalescence during gas-liquid mass transfer. It also helps to reduce the liquid film thickness at the gas-liquid interface, increase the gas-liquid mass transfer area, and reduce mass transfer resistance, playing a key role in enhancing the mass transfer process. Simultaneously, the ionic liquid containing amine functional groups in the solid particles serves as the CO2 adsorption center. Combined with the slurry system, CO2 can be selectively adsorbed from the gas phase and then transported across the gas-liquid interface to the liquid phase for absorption. This absorbent system plays a crucial role in the efficient transport of CO2 and can significantly improve absorption efficiency.

[0032] 2) This invention uses liquid seal isolation to isolate pressure changes in different areas, thereby realizing the functions of high pressure absorption + multi-stage vacuum desorption; this invention reduces the scale of equipment and investment costs, and enhances the desorption efficiency of CO2 through multi-stage desorption, ensuring the decarbonization performance of the slurry system during recycling.

[0033] 3) The composition and ratio of the absorbent system of the present invention have been selected and verified by the inventors through experiments. The absorbent system has the best nano-micro interface enhancement function, gas-liquid mass transfer efficiency and CO2 absorption rate.

[0034] 4) By setting the primary desorption unit as a plate tower with staggered arrangement of the plates and an overflow weir, the present invention can effectively extend the residence time of the slurry to be desorbed in the plate tower, thereby improving the desorption effect; by adopting a tank-type structure for the secondary desorption unit and setting stirring blades inside the tank-type structure, and performing desorption under a higher vacuum, the deep desorption effect can be further improved.

[0035] 5) The present invention provides a regulating valve at the conical liquid seal structure, and interlocks with the corresponding regulating valve through a differential pressure level gauge. The liquid seal height of adjacent units can be controlled by the interlock and the required pressure range can be maintained. At the same time, the circulation rate of the slurry can also be controlled.

[0036] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it according to the contents of the specification, and to make the above and other objects, technical features and advantages of the present invention easier to understand, one or more preferred embodiments are listed below and described in detail with reference to the accompanying drawings. Attached Figure Description

[0037] Figure 1 is a schematic diagram of the connection structure of the carbon capture device of the present invention.

[0038] Explanation of key figure labels:

[0039] 1-Absorption unit; 11-Carbon-containing gas inlet line; 12-Gas distributor; 13-Packaging; 14-Liquid distributor; 15-Top mixed gas line; 16-Absorption unit gas-liquid separator; 17-Liquid reflux line after absorption; 18-Absorption unit regulating valve; 19-Absorption unit differential pressure level gauge; 2-First-stage desorption unit; 21-Train with overflow weir; 22-First-stage top gas discharge line; 23 / 24-Gas discharge line between trays. 25-First-stage vacuum pump; 26-Gas-liquid separator of desorption unit; 27-Regulating valve of first-stage desorption unit; 28-Differential pressure level gauge of first-stage desorption unit; 3-Second-stage desorption unit; 31-Agitator; 32 / 34-Second-stage top gas discharge pipeline; 33-Second-stage vacuum pump; 35-Liquid return pipeline after desorption; 36-Regulating valve of second-stage desorption unit; 37-Differential pressure level gauge of second-stage desorption unit; 4-Slurry circulation pump; 41-Slurry circulation pipeline after desorption. Detailed Implementation

[0040] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0041] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprising" shall be understood to include the stated elements or components without excluding other elements or other components.

[0042] In this document, for ease of description, spatial relative terms such as “below,” “under,” “down,” “above,” “above,” “upper,” etc., are used to describe the relationship of one element or feature to another element or feature in the accompanying drawings. It should be understood that spatial relative terms are intended to encompass different orientations of an object in use or operation, in addition to those depicted in the figures. For example, if an object in the figure is flipped, an element described as “below” or “under” another element or feature would be oriented “above” that element or feature. Thus, the exemplary term “below” can encompass both the downward and upward orientations. An object may also have other orientations (rotated 90 degrees or other orientations), and the spatial relative terms used herein should be interpreted accordingly.

[0043] In this document, the terms "first," "second," etc., are used to distinguish two different elements or parts, and are not used to define specific positions or relative relationships. In other words, in some embodiments, the terms "first," "second," etc., can also be used interchangeably.

[0044] As shown in Figure 1, this invention provides a carbon capture device that integrates the CO2 absorption and desorption processes in the same device, comprising at least an absorption unit 1 and a desorption unit. The absorption unit 1 is located at the top of the device; in the absorption unit 1, the absorbent slurry contacts the carbon-containing gas from top to bottom, undergoing gas-liquid mass transfer under high pressure; the solid phase of the absorbent slurry is a powder of a supported ionic liquid, which is an ionic liquid containing amine groups. The desorption unit is located below the absorption unit 1 and is isolated by a liquid seal; under vacuum conditions, the absorbed slurry undergoes CO2 desorption in the desorption unit, and the desorbed slurry is recycled after gas-liquid separation, with CO2 discharged externally. The desorption unit is configured in at least one stage, preferably multiple stages (Figure 1 illustrates two stages, namely a primary desorption unit 2 and a secondary desorption unit 3); the diameter of the primary desorption unit 2 is preferably larger than the diameter of the absorption unit 1, and the diameters of the multiple desorption units are preferably progressively larger (as shown in Figure 1, the diameter of the secondary desorption unit 3 is larger than the diameter of the primary desorption unit 2).

[0045] Using the above-mentioned technical solution of this invention, an absorbent system with nano-micro interface enhancement function is constructed using a supported ionic liquid as the solid phase and a solvent as the liquid phase. Through a matching process, the nano-micro interface enhancement effect is utilized to effectively improve gas-liquid mass transfer efficiency and increase the CO2 absorption rate. Specifically, the absorbent system with nano-micro interface enhancement function can utilize the irregular movement of solid particles in the slurry to suppress bubble coalescence during gas-liquid mass transfer. It also helps to reduce the liquid film thickness at the gas-liquid interface, increase the gas-liquid mass transfer area, and reduce mass transfer resistance, playing a key role in enhancing the mass transfer process. Simultaneously, the ionic liquid containing amine functional groups in the solid particles serves as the center for CO2 adsorption. Combined with the slurry system, CO2 can be selectively adsorbed from the gas phase and then transported across the gas-liquid interface to the liquid phase for absorption. This absorbent system plays an important role in the efficient transport of CO2 and can significantly improve absorption efficiency. In addition, the liquid seal isolation method can isolate pressure changes in different areas, thereby realizing the function of high pressure absorption + multi-stage vacuum desorption. This invention reduces the scale of equipment and investment costs, and enhances the desorption efficiency of CO2 through two-stage or multi-stage desorption, ensuring the decarbonization performance of the slurry system during recycling.

[0046] Further, preferably but not limitingly, the solid content of the absorbent slurry is 0.5-30% by weight; the ionic liquid is one or more of [APMIm][Br], [Hmim][NTf2], [BMIm][Ac], and the support is one or more of alumina, silica gel, titanium dioxide, activated carbon, and molecular sieve; the loading of the ionic liquid is 1-70%, preferably 2-50%; and the liquid phase of the absorbent slurry is one or more of water and alcohol systems. The inventors have verified through experiments that the nano-micro interface enhancement function of the above absorbent system achieves the best gas-liquid mass transfer efficiency and CO2 absorption rate.

[0047] As shown in Figure 1, the absorption unit 1 can be a packed tower structure or a plate tower structure, preferably a packed tower structure. A liquid distributor 14 is provided at the top of the tower, a gas distributor 12 is provided at the bottom, and packing 13 is filled in the middle. A conical liquid seal structure is provided below the gas distributor 12 to receive the absorbed slurry and maintain a certain liquid level. The packing 13 can be one or more of annular, saddle-shaped, and corrugated shapes, preferably one or more of Pall rings and wire mesh corrugations. A gas-liquid separator 16 is provided at the top of the absorption unit 1. The gas phase is the purified gas after CO2 removal, and the liquid phase is the entrained liquid, which is returned for recycling via the return pipeline 17. A liquid level regulating unit is provided at the corresponding position of the conical liquid seal structure to isolate the pressure operating range between the absorption unit 1 and the primary desorption unit 2, and between the primary desorption unit 2 and the secondary desorption unit 3, and to control the slurry circulation rate. The liquid level control unit includes control valves (specifically, control valve 18 between absorption unit 1 and primary desorption unit 2; and control valve 27 between primary desorption unit 2 and secondary desorption unit 3) and differential pressure level gauges (specifically, differential pressure level gauge 19 of absorption unit is interlocked with control valve 18; and differential pressure level gauge 28 of primary desorption unit is interlocked with control valve 27). The control valves are located at the bottom of the corresponding conical liquid seal structure, and the differential pressure level gauges are interlocked with the corresponding control valves. This interlocking controls the liquid seal height of adjacent units and maintains the required pressure range, while also controlling the slurry circulation rate.

[0048] As shown in Figure 1, the primary desorption unit 2 can be a plate tower or a packed tower structure, preferably a plate tower structure. The plates of the plate tower are preferably staggered and have an overflow weir (i.e., plate 21 with an overflow weir in Figure 1), which can be used to extend the residence time of the slurry to be desorbed in the plate tower. Furthermore, gas discharge pipelines are provided at the top of the primary desorption unit 2 and between the plates (i.e., the primary top gas discharge pipeline 22 and the gas discharge pipelines between the plates 23 / 24 in Figure 1), so that the desorbed CO2 can be discharged in a timely manner, and the slurry after gas-liquid separation can be recycled.

[0049] As further shown in Figure 1, the secondary desorption unit 3 preferably adopts a tank-type structure, and the tank-type structure may be equipped with stirring blades. The secondary desorption of the present invention preferably further desorbs CO2 under a higher vacuum degree than that of the primary desorption unit. A gas discharge pipeline (i.e., the secondary top gas discharge pipeline 32 / 34 in Figure 1) is provided at the top of the secondary desorption unit 3 to discharge the desorbed CO2 in a timely manner, and the slurry after gas-liquid separation is recycled.

[0050] As further shown in Figure 1, the desorbed slurry in the secondary desorption unit 3 is pumped by the slurry circulation pump 4 to the liquid distributor 14 in the absorption unit 1 for recycling. This invention completes the aforementioned high-pressure absorption and two-stage vacuum desorption in different units within the same device, enabling the recycling of the absorbent and allowing for continuous operation of the entire process. This not only improves absorption efficiency but also effectively reduces the scale of the equipment and investment costs.

[0051] Referring to Figure 1, the present invention also provides a carbon capture method, which, using the aforementioned apparatus, includes at least the following steps:

[0052] Step S101, CO2 absorption process: In absorption unit 1, the absorption slurry is in countercurrent contact with carbon-containing gas (the CO2 concentration of the carbon-containing gas can range from 10% to 80%, preferably 15% to 50%) from top to bottom, performing gas-liquid mass transfer under high pressure. The irregular movement of solid particles in the slurry suppresses bubble coalescence during the gas-liquid mass transfer process. The solid particles in the slurry, with ionic liquids containing amine functional groups as CO2 adsorption centers, adsorb CO2 from the gas phase and then pass through the gas-liquid interface, transporting CO2 to the liquid phase for absorption. That is, the carbon-containing gas enters from the bottom of absorption unit 1, and the slurry system enters from the top of absorption unit 1, absorbing CO2 in countercurrent contact within the absorption unit. The decarbonized gas enters the gas-liquid separator 16 of the absorption unit, the gas phase is discharged as decarbonized gas, and the collected liquid phase is returned to absorption unit 1. The slurry that has absorbed CO2 is discharged from the bottom of the absorption unit and enters the first-stage desorption unit 2. The operating temperature of the CO2 absorption process can be 5–50℃, preferably 25–35℃; the operating pressure can be 0–2MPa, preferably 0.2–1MPa; and the liquid-to-gas volume ratio can be 0.1–2, preferably 0.3–0.8.

[0053] In step S102, a portion of the absorbed slurry forms a liquid seal at the bottom of the absorption unit 1. The liquid seal controls the required pressure and slurry circulation rate in the absorption unit 1 and the first-stage desorption unit 2 through the interlocking of the regulating valve and the differential pressure level gauge.

[0054] Step S103, CO2 desorption process: Another portion of the slurry after absorption enters the primary desorption unit 2, where primary CO2 desorption is performed under vacuum. The desorbed slurry can be recycled. Preferably, but not limitingly, this step may also include a secondary desorption process. The primary and secondary desorption processes are also isolated by a liquid seal (the interlock control process is the same as in step S102). The secondary desorption has a higher vacuum degree than the primary desorption. The slurry from the absorption unit 1 undergoes primary CO2 desorption under vacuum. The desorbed gas is discharged from the top of the primary desorption unit 2 and enters the gas-liquid separator 26 of the desorption unit. The gas phase is high-purity CO2, and the collected liquid phase can be returned to the secondary desorption unit 3. The slurry after primary desorption is discharged from the bottom and enters the secondary desorption unit 3. Under the higher vacuum of the secondary desorption unit 3, further desorption occurs, improving the CO2 desorption efficiency and ensuring the decarbonization capacity of the slurry system. The desorbed gas is discharged from the top of the secondary desorption unit 3 and enters the gas-liquid separator 26. The gas phase is high-purity CO2, and the separated liquid phase can be returned to the secondary desorption unit 3. Preferably, but not limitingly, the residence time of the slurry can be extended during the primary desorption process using staggered trays and an overflow weir structure; the slurry can be stirred during the secondary desorption process. The desorbed slurry in the secondary desorption unit can be returned to the absorption unit 1 for recycling. The operating temperature of the primary desorption process can be 5–50℃, preferably 25–35℃; the operating pressure can be -200–0 kPa, preferably -50–0 kPa. The operating temperature for the secondary desorption process is 5–50℃, preferably 25–35℃; the operating pressure can be -300–-20 kPa, preferably -150–-80 kPa.

[0055] The carbon capture method of the present invention can achieve the same technical effect as the aforementioned device, and will not be described in detail here.

[0056] Example 1

[0057] Referring to Figure 1, nitrogen and carbon dioxide from the utility system pass through a ball valve and a filter, and then are reduced and stabilized by a pressure reducing valve. After the flow rate is measured by the gas mass flow control, the two gases are mixed to prepare a raw material gas with a CO2 concentration of 40.2%, which enters the absorption unit 1 of the packing tower structure at a rate of 599.48 L / h.

[0058] The slurry from the secondary desorption unit 3, after passing through a ball valve and filter, is pumped by a centrifugal pump (i.e., slurry circulation pump 4) into a flow meter and control valve for metering. The slurry is then sprayed into the packed tower at a rate of 553.84 L / h from the liquid distributor 14 at the top, where it comes into countercurrent contact with the raw gas at the bottom of the tower at 25°C and 0.6 MPa for absorption. The absorbed CO2 gas enters the gas-liquid separator 16 from the top of the tower for water sedimentation. The sedimented liquid is collected in the gas-liquid separator and returned to the packed tower. The decarbonized gas is discharged after the pressure of the absorption unit 1 is stabilized by the back pressure valve. The slurry at the bottom of the absorption tower, after its level is controlled by the absorption unit regulating valve 18 and the absorption unit differential pressure level gauge 19, enters the primary desorption unit 3. The CO2 concentration in the decarbonized gas after absorption unit 1 is 1.86%, and the carbon capture efficiency is 95.37%.

[0059] After the slurry from absorption unit 1 enters the primary desorption unit 2, it flows downwards through tray 21 with an overflow weir, undergoing desorption under a vacuum of 25℃ and -10kPa. The desorbed CO2 is extracted from the top of the tray column and the pipelines between the trays in the primary desorption unit 2; it then enters the gas-liquid separator 26 for water sedimentation. The settled liquid is collected in the gas-liquid separator and returned to the secondary desorption unit 3. The resulting CO2 is mixed with the CO2 desorbed in the secondary desorption unit, and the gas concentration is tested before being discharged into the atmosphere. The tested CO2 purity is 99.7%. The slurry at the bottom of the primary desorption unit 2 enters the secondary desorption unit 3 after its level is controlled by the primary desorption unit regulating valve 27 and the primary desorption unit differential pressure level gauge 28.

[0060] After the slurry from the primary desorption unit 2 enters the secondary desorption unit 3, it undergoes deep desorption by stirring at 2000 rpm under a vacuum of 25℃ and -60 kPa. The desorbed CO2 is extracted from the top and enters the gas-liquid separator 26 for water sedimentation. The settled liquid is collected in the separator and returned to the secondary desorption unit 3. The obtained CO2 is mixed with the CO2 desorbed from the primary desorption unit and then discharged. The slurry at the bottom of the secondary desorption unit 3 is controlled by the interlock between the secondary desorption unit regulating valve 36 and the secondary desorption unit differential pressure level gauge 37, and then transported to the absorption unit 1 by a centrifugal pump (i.e., the slurry circulation pump 4) to complete the recycling of the slurry.

[0061] The foregoing description of specific exemplary embodiments of the present invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. Any simple modifications, equivalent changes, and alterations made to the foregoing exemplary embodiments should fall within the scope of protection of the present invention.

Claims

1. A carbon capture device, characterized in that, The device integrates the CO2 absorption and desorption processes for carbon capture into a single unit, comprising: an absorption unit disposed at the top of the device; in the absorption unit, an absorption slurry contacts carbon-containing gas from top to bottom and from bottom to top, performing gas-liquid mass transfer under high pressure; the solid phase of the absorption slurry is a powder of a supported ionic liquid, wherein the ionic liquid contains amine groups; and a desorption unit disposed below the absorption unit and isolated by a liquid seal; under vacuum conditions, the absorbed slurry undergoes CO2 desorption in the desorption unit, and the desorbed slurry is recycled after gas-liquid separation, with CO2 discharged externally.

2. The carbon capture device according to claim 1, characterized in that, The absorption unit is a packed tower structure with a liquid distributor at the top, a gas distributor at the bottom, and packing material in the middle. Below the gas distributor is a cone-shaped liquid seal structure for receiving the absorbed slurry and maintaining a certain liquid level.

3. The carbon capture device according to claim 2, characterized in that, The desorption unit is configured in multiple stages; the diameter of the first-stage desorption unit is larger than the diameter of the absorption unit, and the diameter of the multi-stage desorption units increases progressively.

4. The carbon capture device according to claim 1, characterized in that, The solid content of the absorbent slurry is 0.5-30% by weight; the ionic liquid is one or more of [APMIm][Br], [Hmim][NTf2], [BMIm][Ac], and the carrier is one or more of alumina, silica gel, titanium dioxide, activated carbon, and molecular sieve; the loading of the ionic liquid is 2-50%; and the liquid phase of the absorbent slurry is one or more of water and alcohol systems.

5. The carbon capture device according to claim 2, characterized in that, The packing material of the absorption unit is one or more of the following: annular, saddle-shaped, and corrugated.

6. The carbon capture device according to claim 3, characterized in that, The cone-shaped liquid seal structure is equipped with a liquid level regulating unit at the corresponding position, which is used to isolate the pressure operating range between the absorption unit and the multi-stage desorption unit and to control the circulation rate of the slurry.

7. The carbon capture device according to claim 6, characterized in that, The liquid level regulating unit includes: a regulating valve disposed at the bottom of the conical liquid seal structure; a differential pressure level gauge interlocked with the regulating valve, which controls the liquid seal height of adjacent units and maintains the required pressure range through interlocking, and controls the circulation rate of the slurry.

8. The carbon capture device according to claim 3, characterized in that, The desorption unit is configured in two stages; the first stage desorption unit is a plate tower structure, with the plates of the plate tower arranged alternately and having an overflow weir, which is used to extend the residence time of the slurry to be desorbed in the plate tower.

9. The carbon capture device according to claim 8, characterized in that, Gas discharge pipelines are installed at the top of the primary desorption unit and between the trays to discharge the desorbed CO2 in a timely manner, and the slurry after gas-liquid separation is recycled.

10. The carbon capture device according to claim 8, characterized in that, The secondary desorption unit is a tank-type structure with stirring blades inside, which further desorbs CO2 under a higher vacuum degree than the primary desorption unit.

11. The carbon capture device according to claim 10, characterized in that, The secondary desorption unit is equipped with a gas discharge pipeline at the top to discharge the desorbed CO2 in a timely manner, and the slurry after gas-liquid separation is recycled.

12. The carbon capture device according to claim 11, characterized in that, The slurry desorbed in the secondary desorption unit is pumped to the liquid distributor in the absorption unit by the slurry circulation pump for recycling.

13. The carbon capture device according to claim 2, characterized in that, The absorption unit is equipped with a tower top mixing gas pipeline. After gas-liquid separation, the decarbonized gas is discharged and the liquid is returned to the liquid distributor for recycling.

14. A carbon capture method, characterized in that, The apparatus according to any one of claims 1 to 13 comprises the following steps: A. CO2 absorption process: In the absorption unit, the absorption slurry is in countercurrent contact with the carbon-containing gas from bottom to top, and gas-liquid mass transfer is carried out under high pressure. The irregular movement of solid particles in the slurry is used to suppress the coalescence of bubbles during the gas-liquid mass transfer process. The solid particles in the slurry use ionic liquids containing amine functional groups as the centers for CO2 adsorption, adsorbing CO2 from the gas phase and then passing through the gas-liquid interface to transport CO2 to the liquid phase for absorption; B. A portion of the absorbed slurry forms a liquid seal at the bottom of the absorption unit. The liquid seal controls the required pressure and slurry circulation rate in the absorption unit and the primary desorption unit through interlocking; C. CO2 desorption process: Another portion of the absorbed slurry enters the primary desorption unit and performs primary CO2 desorption under vacuum. The desorbed slurry is recycled.

15. The carbon capture method according to claim 14, characterized in that, Step C also includes a secondary desorption process, in which the primary and secondary desorption processes are isolated by a liquid seal, and the secondary desorption process has a higher vacuum degree than the primary desorption process.

16. The carbon capture method according to claim 15, characterized in that, During the first-stage desorption process, the residence time of the slurry is extended by using staggered tower plates and an overflow weir structure; during the second-stage desorption process, the slurry is stirred.

17. The carbon capture method according to claim 15, characterized in that, The slurry after primary and / or secondary desorption is returned to the absorption unit for recycling, and the desorbed CO2 is discharged.

18. The carbon capture method according to claim 14, characterized in that, The decarbonized gas obtained in the CO2 absorption process is discharged after gas-liquid separation, and the separated liquid is recycled as absorption slurry.

19. The carbon capture method according to claim 14, characterized in that, The operating temperature of the CO2 absorption process is 5–50°C; the operating pressure is 0–2 MPa; and the liquid-to-gas volume ratio is 0.1–2.

20. The carbon capture method according to claim 15, characterized in that, The operating temperature of the first-stage desorption process is 5–50°C, and the operating pressure is -50–0 kPa; the operating temperature of the second-stage desorption process is 5–50°C, and the operating pressure is -150–-80 kPa.

21. The carbon capture method according to claim 14, characterized in that, The CO2 concentration of the carbon-containing gas ranges from 10% to 80%.

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