A bubble barrier-eliminating analytical column apparatus and method

Abstract

The application discloses a kind of analytic tower devices and methods for eliminating bubble barrier, belong to carbon dioxide capture technical field, including analytic tower, air pipe, first purging unit and second purging unit;The catalyst bed layer is equipped in the analytic tower, for resolving CO2 And provide CO2 tail gas to first purging component and second purging component;The first purging unit is fixed in the inner wall of the analytic tower, and is placed below the catalyst bed layer;One end of the second purging unit is fixed in the inner wall of the analytic tower, and the other end extends into the catalyst bed layer;The first purging unit and the second purging unit are used to provide the gas that peeling catalyst surface adheres bubble;One end of the air pipe is communicated with the exhaust pipe of the analytic tower, and the other end extends into the interior of the analytic tower, and is communicated with first purging unit and second purging unit respectively.The application uses active purging, effectively eliminates the bubble on the surface of catalyst, reduces energy consumption and reduces cost.

Description

Technical Field

[0001] This invention belongs to the field of carbon dioxide capture technology, specifically relating to an analytical tower device and method for eliminating bubble barriers. Background Technology

[0002] In the amine-based carbon capture process, the amine solution in the absorption tower absorbs CO2 to generate a rich solution. This rich solution then enters the stripping tower (regeneration tower), where CO2 is released under heating conditions in the presence of a catalyst (such as a solid acid catalyst or a metal oxide catalyst). During stripping, a large number of CO2 bubbles nucleate, grow, and aggregate on the catalyst surface and inside the amine solution. These bubbles form a gas film barrier around the catalyst particles, hindering sufficient contact between the amine solution and the active sites of the catalyst, leading to a decrease in stripping efficiency and a reduction in the reaction rate.

[0003] Industrially, bubble desorption is mainly assisted by mechanical stirring, ultrasonic oscillation, and the addition of defoamers. Patent CN117815712A discloses a foam elimination device and method for tower equipment. This patent mainly uses mechanical rotation and defoamers, but it suffers from complex solutions and high energy consumption. Patent CN119565332A discloses a regeneration tower device and a carbon dioxide capture system incorporating it. A bubble-breaking structure is set below the packing structure inside the regeneration tower. The bubble-breaking structure includes a rotating shaft and multiple blades set on the rotating shaft. The impeller directly breaks the bubbles through mechanical rotation. Although this solution does not require the addition of defoamers, it requires a motor drive mechanism, which leads to wear and maintenance issues for rotating parts. In summary, current defoaming methods have many drawbacks: 1) Whether adding internal components or adjusting the flow field, most methods rely on waiting for bubbles to naturally desorb or being carried away by the overall flow, lacking active purging methods for bubbles adhering to the catalyst surface; 2) High operating costs: mechanical stirring and ultrasonic solutions consume a lot of energy, while defoamers need to be added continuously, both of which are long-term expenses; 3) Difficult engineering modifications: the solutions require replacing tower internals or adding large moving equipment, resulting in long on-site construction cycles and are not suitable for continuously operating industrial plants. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a desorption tower device and method for eliminating bubble barriers. This invention utilizes the CO2 tail gas generated by the desorption tower and adopts an active purging method to eliminate bubble barriers in the catalyst bed, thus solving the drawbacks of the prior art such as high energy consumption, complex equipment, difficult construction and high operating costs.

[0005] This invention provides the following technical solution:

[0006] In a first aspect, a desorption tower device for eliminating bubble barriers is provided, comprising a desorption tower, an air intake pipe, a first purging unit, and a second purging unit; The desorption tower is equipped with a catalyst bed for desorbing CO2 and supplying CO2 tail gas to the first purging assembly and the second purging assembly; The first purging unit is fixed to the inner wall of the desorption tower and placed below the catalyst bed; one end of the second purging unit is fixed to the inner wall of the desorption tower, and the other end extends into the catalyst bed; the first purging unit and the second purging unit are used to provide gas to strip bubbles adhering to the catalyst surface; One end of the air intake pipe is connected to the exhaust pipe of the analytical tower, and the other end extends into the interior of the analytical tower and is connected to the first purging unit and the second purging unit respectively.

[0007] Furthermore, the first purging unit includes an annular tube assembly, which includes one or more annular tubes connected to the gas inlet pipe. Each annular tube is arranged concentrically with the desorption tower and positioned 10-20 mm below the catalyst bed. The annular tube has multiple first openings on the side facing away from the catalyst bed.

[0008] Furthermore, the first purging unit is a sintered plate connected to the gas inlet pipe. The sintered plate is horizontally placed 50-100 mm below the catalyst bed, and its sidewall is fixed to the inner wall of the desorption tower. The sintered plate has a porous metal structure, and the porosity of the sintered plate surface is 15% to 40%.

[0009] Furthermore, the second purging assembly includes multiple Venturi injection rods, with one side of each Venturi injection rod evenly distributed along the desorption tower and the other side extending into the middle of the catalyst bed, and connected to the gas inlet pipe respectively.

[0010] Furthermore, the gas inlet pipe is sequentially provided with a gas-liquid separator, a filter, a first flow meter, and a regulating valve along the gas flow direction; The bottom of the gas-liquid separator is connected to the rich liquid feed pipe of the desorption tower via a condensate reflux pipe.

[0011] Furthermore, the catalyst bed is equipped with an end differential pressure transmitter, and the rich liquid inlet pipe of the desorption tower is equipped with a second flow meter and a CO2 detection unit.

[0012] In a second aspect, a method for eliminating bubble barriers using an analytical column apparatus employing any one of the first aspects is provided, comprising: Inert gas is introduced into the stripping tower to start the amine liquid circulation; After the amine solution circulation stabilizes, turn off the inert gas, open the priming pipe, and purge the catalyst bed based on the purging gas volume benchmark value. The rich liquid flow rate and CO2 loading are monitored in real time, and the rich liquid feedforward signal is obtained based on the rich liquid design flow rate and CO2 loading threshold. The pressure difference change of the catalyst bed is monitored in real time to obtain the pressure difference feedback signal. The rich liquid feedforward signal and the pressure difference feedback signal are superimposed to dynamically adjust the purging gas volume, determine the final value of the purging gas volume, and purge the catalyst bed. After the reaction is complete, close the gas inlet pipe, shut off the amine solution circulation, and stop the operation.

[0013] Furthermore, the purge gas volume reference value is 10~15 mL / min.

[0014] Furthermore, the real-time monitoring of the rich solution flow rate and CO2 load, and the generation of a rich solution feedforward signal based on the rich solution design flow rate and CO2 load threshold, includes: Real-time monitoring of the rich liquid flow rate, and determination of the first purge gas volume based on the rich liquid design flow rate and purge gas volume benchmark values, including: When the rich liquid flow rate is greater than or equal to 80% of the rich liquid design flow rate, the first purging gas volume is 115-150% of the baseline value of the purging gas volume. For every 10% increase in the rich liquid flow rate, the first purging gas volume increases by 15% of the baseline value of the purging gas volume. When 50% of the design flow rate of the rich liquid is less than the flow rate of the rich liquid and less than 80% of the design flow rate of the rich liquid, the first purge gas volume is the reference value of the purge gas volume. When the rich liquid flow rate is ≤ 50% of the rich liquid design flow rate, the first purging gas volume is 30%~70% of the purging gas volume benchmark value. Among them, for every 10% decrease in the rich liquid flow rate, the first purging gas volume is reduced by 10% of the purging gas volume benchmark value. Real-time monitoring of CO2 load, and determination of the second purge gas volume based on CO2 load threshold and purge gas volume baseline: When the CO2 loading is ≥0.40 mol / mol, the second purge gas volume is 120%~150% of the purge gas volume baseline value; When 0.25 mol / mol < CO2 loading < 0.40 mol / mol, the second purge gas volume is the baseline value for the purge gas volume; When the CO2 loading is ≤0.25 mol / mol, the second purge gas volume is 50%~70% of the baseline purge gas volume. The rich liquid feedforward signal is obtained based on the maximum value of the first purge gas volume and the second purge gas volume.

[0015] Furthermore, the real-time monitoring of the pressure difference change in the catalyst bed to obtain the pressure difference feedback signal includes: The pressure differential rise rate of the catalyst bed is monitored in real time, and the purging gas volume is dynamically adjusted based on the purging gas volume baseline value to determine the third purging gas volume. When the rate of pressure rise is ≥0.5 kPa / min and the duration is ≥1 min, the first step length is increased to obtain the third purge gas volume, and the first purge gas increment is 10%~20% of the purge gas volume baseline value; When the differential pressure recovery rate is ≤0.1 kPa / min, stop increasing the first step length and restore the purge gas volume to the baseline value; The absolute value of the pressure difference in the catalyst bed is monitored in real time, and the purging gas volume is dynamically adjusted based on the pressure difference reference value and the purging gas volume reference value to determine the fourth purging gas volume. When the absolute value of the pressure difference is greater than or equal to 130% of the pressure difference reference value, the second step size is increased to obtain the fourth purge gas volume. The second step size is 20% to 30% of the purge gas volume reference value. When the absolute value of the pressure difference is less than or equal to 105% of the pressure difference reference value, the purge gas volume is restored to the reference value at a rate of 5% / min. The differential pressure feedback signal is obtained based on the maximum values ​​of the third and fourth purge gas volumes.

[0016] Furthermore, the rich liquid feedforward signal and the differential pressure feedback signal are superimposed to dynamically adjust the purge gas flow rate, determine the final value of the purge gas flow rate, and terminate the purge gas flow to purge the catalyst bed, including: The rich liquid feedforward signal and the differential pressure feedback signal are superimposed to obtain the calculated purge gas volume value, and the final value of the real-time purge gas volume is determined. The determination of the final value of the real-time purge gas volume includes: When the calculated purge air volume is greater than 150% of the purge air volume reference value, the final purge air volume is 150% of the purge air volume reference value, and an alarm signal is issued simultaneously. When 20% of the purge gas volume baseline value ≤ the purge gas volume calculated value ≤ 150% of the purge gas volume baseline value, the final purge gas volume value is the purge gas volume calculated value. When the calculated purge air volume is less than 20% of the purge air volume reference value, the final purge air volume value is 20% of the purge air volume reference value. The catalyst bed is purged based on the final value of the real-time purging gas volume.

[0017] Compared with the prior art, the beneficial effects of the present invention are: (1) The analytical tower device provided by the present invention is provided with a first purging unit and a second purging unit. Each purging unit is connected to the exhaust pipe of the analytical tower through an air intake pipe. The CO2 tail gas produced by the system is directly used as the purging gas to purge the catalyst bed. The shear force of the airflow is used to peel off the adhering bubbles, forming an active and efficient bubble barrier. This reduces the long-term coverage of the catalyst surface by bubbles and local overheating. At the same time, the shearing and scouring effect of the airflow is slight and will not cause significant wear of the catalyst particles. This effectively improves the catalytic rate and extends the service life of the catalyst. (2) According to the rich liquid flow rate, CO2 load or bed pressure difference signal, the purge gas volume can be dynamically adjusted to adapt to flue gas load fluctuations. The purge gas uses CO2-containing tail gas produced by the system itself, without adding any chemical agents, and will not pollute the amine liquid or produce by-products such as heat-stable salts, which is conducive to extending the service life of the equipment and reducing maintenance costs. (3) This invention only needs to overcome the resistance of the pipeline and distributor (generally a pressure drop of 2~5 kPa), and can utilize the residual pressure at the top of the tower. No additional pressurization is required. The additional power consumption per ton of CO2 is less than 0.05 kWh, which is about 5% of that of the mechanical defoaming solution. (4) The analytical tower device provided by the present invention is easy to modify. It only requires adding an exhaust gas pipeline and a gas-liquid separator outside the tower, and installing a ring pipe, a sintered plate distributor or a Venturi spray rod inside the tower. It does not require replacing the internal parts of the tower or adding large moving equipment. The modification can generally be completed in 3 to 5 days of shutdown. Attached Figure Description

[0018] Figure 1 This is the desorption tower device for eliminating bubble barriers in Embodiment 1 of the present invention; Figure 2 The first purging unit in Embodiment 1 of the present invention is an annular tube assembly for eliminating bubble barriers in the analytical tower device. Figure 3 The first purging unit in Embodiment 1 of the present invention is a desorption tower device for eliminating bubble barriers using a sintered plate; Figure 4 This is a flowchart of the method for eliminating bubble barriers in Embodiment 2 of the present invention.

[0019] The following are labeled in the diagram: 1. Desorption tower; 2. Catalyst bed; 3. Gas inlet pipe; 4. First purging unit; 41. Annular pipe assembly; 411. First opening; 42. Sintered plate; 421. Fixture; 5. Second purging unit; 6. First flow meter; 7. Second flow meter; 8. Rich liquid inlet pipe; 9. Gas-liquid separator; 10. Filter; 11. Control valve; 12. Condensate return pipe. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0021] It should be noted that in the description of this invention, the terms "front", "rear", "left", "right", "upper", "lower", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and do not require that this invention must be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0022] In the description of this invention, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0023] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0024] In the description of this invention, unless otherwise stated, "a plurality of" means two or more. The terms "comprising," "including," "having," "containing," etc., as used herein are open-ended, meaning they include but are not limited to.

[0025] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0026] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0027] Example 1

[0028] This embodiment provides a desorption tower device for eliminating bubble barriers, including a desorption tower 1, an air intake pipe 3, a first purging unit 4, and a second purging unit 5;

[0029] like Figure 1As shown, the stripping tower 1 contains a catalyst bed 2, on which catalyst is uniformly arranged to provide a catalytic environment for CO2 stripping. An exhaust pipe is located at the top of the stripping tower 1, through which CO2 is collected. In this embodiment, the installation positions of the stripping tower 1, catalyst bed 2, and exhaust pipe are consistent with those of existing equipment and installation positions, and are adapted to meet actual needs.

[0030] like Figure 1 As shown, one end of the gas inlet pipe 3 is connected to the exhaust pipe at the top of the analytical column 1, allowing CO2 in the exhaust pipe to flow to the gas inlet pipe 3. In one possible embodiment, a T-junction is installed on the exhaust pipe at the top of the analytical column 1, connecting one end of the gas inlet pipe 3 to the exhaust pipe. In some possible embodiments, the nominal diameter of the exhaust pipe is DN150 to DN300, and the nominal diameter of the gas inlet pipe is DN25 to DN50. The gas temperature exiting from the top of the analytical column is 80 to 120°C, and the gas contains water vapor and a small amount of ammonia. To ensure that the gas inlet pipe 3 obtains pure CO2, a gas-liquid separator 9, a filter 10, a first flow meter 6, and a regulating valve 11 are sequentially installed on the gas inlet pipe 3. In one possible embodiment, a wire mesh demister may be installed inside the gas-liquid separator 9 to block liquid droplets. A condensate return pipe 12 is provided at the bottom of the gas-liquid separator 9, which is connected to the rich liquid feed pipe 8 of the analytical column 1. In one possible embodiment, a filter 10 is installed after the gas-liquid separator 9 to trap dust and prevent nozzle clogging. In one possible embodiment, the filter 10 is a 10 μm filter. The other end of the gas inlet pipe 3 is connected to the interior of the desorption tower 1 and the pipeline distributor of the desorption tower 1, and is connected to the first purging unit 4 and the second purging unit 5 respectively. In one possible embodiment, multiple branch pipes can be opened on the gas inlet pipe 3 for independent connection to each purging unit. A first flow meter 6 and a regulating valve are installed after the gas-liquid separator and the filter and before the distributor inside the tower to regulate the purging gas flow rate.

[0031] like Figure 1 As shown, the first purging unit 4 is fixed to the inner wall of the desorption tower 1 and placed below the catalyst bed 2. Figure 2As shown, in one possible embodiment, the first purging unit 4 is an annular tube assembly 41. The annular tube assembly 41 is suitable for stripping towers with small diameters. The annular tube assembly 41 is placed 10-20 mm below the catalyst bed 2 and is arranged concentrically with the stripping tower 1. In one possible embodiment, the annular tube assembly 41 is made of stainless steel and bent into an annular gas distribution pipe concentric with the tower body of the stripping tower 1. The annular tube assembly 41 is welded and fixed to the inner wall of the stripping tower 1 by angle steel brackets. The annular tube assembly 41 includes one or more annular tubes, each with a nominal diameter of DN15-DN25, and each annular tube is connected to a branch of the gas inlet pipe 3. In one possible embodiment, the number of annular tubes is arranged in stages according to the tower diameter of the stripping tower 1: when the tower diameter is <1.5 m, one annular tube is provided; when the tower diameter is between 1.5 and 3 m, two concentric annular tubes are provided; when the tower diameter is >3 m, three or more concentric annular tubes are provided. The spacing between adjacent annular tubes is 150-250 mm. Each annular tube has several 0.5-1 mm first openings 411, facing downwards or diagonally downwards, avoiding upward openings to prevent backflow and blockage by catalyst particles or amine liquid. The total area of ​​the openings on the annular tubes accounts for approximately 0.5%-1.5% of the tower cross-sectional area to ensure uniform distribution of the purging gas.

[0032] like Figure 3 As shown, in one possible embodiment, the first purging unit 4 includes a sintered plate 42, which is horizontally installed 5-10 cm below the catalyst bed 2. The sintered plate 42 is positioned below the catalyst bed 2 and connected to a branch of the gas inlet pipe 3. In one possible embodiment, the sintered plate 42 is a porous metal sintered plate, and the connection between the sintered plate 42 and the branch of the gas inlet pipe 3 adopts the commonly used connection method for sintered plates and pipes. The sidewall of the sintered plate 42 is connected to the inner wall of the desorption tower 1 by a fastener. In one possible embodiment, the fastener 421 is an annular support angle steel or a grid bracket welded on the desorption tower 1. In one possible embodiment, a heat-resistant sealing gasket is used to seal the edge of the sintered plate 42 with the tower wall of the desorption tower 1 to prevent short-circuiting of the gas flow, such as a graphite composite gasket or flexible graphite packing. In one possible embodiment, the pretreated CO2 tail gas in the gas inlet pipe 3 enters the annular sealed gas chamber of the sintering plate 42, passes through the micropores on the entire sintering plate 42 from bottom to top, and enters the catalyst bed 2, achieving uniform gas distribution across the entire cross-section of the catalyst bed 2. The plate surface porosity is 15%~40% (depending on the sintering plate material and pore size), the overall pressure drop is 2~5 kPa, and the gas distribution uniformity is good, making it suitable for industrial conditions with high requirements for gas flow uniformity and large bed cross-sections. In some possible embodiments, a low-frequency vibrating gas distribution plate can be installed on the sintering plate 42 to further reduce the minimum purging gas volume.

[0033] like Figure 1As shown, one end of the second purging unit 5 is fixed to the inner wall of the desorption tower 1, and the other end extends into the catalyst bed 2. The second purging unit 5 includes multiple Venturi spray rods. One side of each Venturi spray rod is evenly arranged along the cross-section of the desorption tower 1, and the other side extends into the middle of the catalyst bed 2 and is connected to the gas inlet pipe 3. The CO2 tail gas generated at the top of the desorption tower 1 is connected to each Venturi spray rod through the gas inlet pipe. The high-speed spray of the Venturi spray rods forms a local negative pressure to entrain the adhesive liquid and spray it out simultaneously, which has both flushing and mixing effects. It is suitable for complex systems that are prone to scaling and have high adhesive viscosity, and its structural complexity is relatively higher.

[0034] In some possible embodiments, nitrogen can be used as an auxiliary gas if there is insufficient CO2 exhaust gas, but the economic efficiency will be reduced.

[0035] In some possible embodiments, the desorption tower 1 also includes a third purging assembly, which is a multi-layer distribution tube. The multi-layer distribution tube is inserted from the middle (halfway up the height) of the catalyst bed 2 to achieve segmented purging, suitable for industrial towers with a bed height greater than 3 m.

[0036] In some possible embodiments, purge gas is pre-mixed into the rich liquid feed line at the bottom of the desorption tower 1 to form a gas-liquid two-phase flow that enters the tower, and the desorption is assisted by the Taylor bubble breakage effect.

[0037] In some possible embodiments, the purging unit provided in this embodiment is combined with the catalyst bed to modify the catalyst surface hydrophobically (e.g., by coating with a hydrophobic coating or a superhydrophobic coating). This can reduce bubble adhesion by 50%–80%, allowing for use with a smaller purging gas volume (reducing the purging gas volume by 30%–50%). The effect is confirmed by contact angle measurement (target ≥120°), bubble adhesion testing, or high-speed imaging to observe bubble desorption behavior. The purging is combined with low-pressure ultrasonic waves (2040 kHz, 0.05–0.2 W / cm²). 2 By combining these methods, the bubble residence time can be reduced by 60% to 80%, and the purge air volume can be further reduced by 30% to 50%. This can be confirmed by using high-speed cameras to statistically analyze the bubble residence time or by comparing it with the critical purge air volume.

[0038] Example 2

[0039] like Figure 4 As shown, this embodiment, based on the analytical tower apparatus of Embodiment 1, provides a method for eliminating bubble barriers, including the following steps.

[0040] S0. Conduct a preliminary experiment to eliminate air bubbles and determine the baseline for bubble purging.

[0041] In one possible embodiment, a purge gas rate gradient experiment was conducted on a laboratory-scale pilot-scale apparatus (column diameter approximately 50-100 mm, catalyst loading height approximately 500 mm) to investigate the effects of different purge gas rates on the catalyst surface bubble coverage, CO2 desorption rate, and amine entrainment rate. The purge gas was simulated CO2-containing tail gas from the top of the desorption column (CO2 concentration approximately 85%, the remainder being water vapor and N2). The CO2 tail gas entered the annular tube assembly 41 via the initiator tube 3 and was ejected from below the catalyst bed 2. A high-speed camera was used to photograph the bubble coverage on the catalyst bed 2 surface through a viewing window on the side wall of the desorption column 1, and the bubble coverage was statistically analyzed using image processing software. The desorption rate was obtained by online analysis of the outlet gas CO2 concentration using gas chromatography and calculation of the CO2 release per unit time. The amine entrainment rate was determined by weighing the collected liquid in a wire mesh demister downstream of the catalyst bed 2 outlet. Experimental results show that: without the introduction of purge gas, approximately 72% of the catalyst surface area is covered by adhering bubbles; when the purge gas flow rate increases to 5 mL / min, the bubble coverage rate decreases to approximately 35%, and the CO2 desorption rate increases by approximately 18% compared to the unpurged state; when the purge gas flow rate reaches 10 mL / min, the coverage rate further decreases to approximately 12%, and the desorption rate increases by approximately 36%; when the purge gas flow rate is 15 mL / min, the coverage rate is only about 6%, and the desorption rate increases by approximately 42%, which is already very significant; when the purge gas flow rate continues to increase to 20 mL / min, the coverage rate decreases to approximately 3%, and the desorption rate increases by approximately 45%, but the amine entrainment rate increases significantly from 0.2% to 1.5%, indicating that excessive purge gas flow has caused significant amine entrainment problems, constituting a limiting factor for the safe upper limit of the purge gas flow rate.

[0042] Based on the above data, a purge gas flow rate of 10–15 mL / min represents the optimal operating range, achieving a high desorption rate (36%–42% improvement) while maintaining a low risk of amine entrainment (entrainment rate ≤0.5%). In subsequent practical engineering projects, the purge gas flow rate will be based on this range and dynamically adjusted according to actual operating conditions. The industrial scale-up values ​​corresponding to the above data need to be proportionally converted based on the ratio of column cross-sectional area to catalyst loading to maintain a consistent apparent gas velocity. 150% of the purge gas flow rate baseline corresponds to the critical value for a sudden increase in amine entrainment rate under small-scale conditions, serving as a safety upper limit.

[0043] S1. Inert gas is introduced into the stripping tower 1 to start the amine liquid circulation.

[0044] According to the actual engineering requirements, a CO2 capture device is arranged, and an inert gas, such as nitrogen, is introduced into the stripping tower 1. The flow rate of the inert gas is about 10% to 20% of the baseline value of the purging gas flow rate, in order to protect the catalyst bed 2 and prevent the amine liquid from flowing back into the gas inlet pipe.

[0045] S2. After the amine liquid circulation stabilizes, turn off the inert gas and open the priming pipe 3. Based on the purging gas volume benchmark value, purge the catalyst bed 2.

[0046] After the amine liquid circulation stabilizes, the nitrogen gas is gradually reduced and switched to CO2 tail gas. At the same time, based on the purge gas volume benchmark value, the purge gas volume is increased to the set value to purge the catalyst bed 2. During the entire purging process, the annular tube assembly 41, sintering plate 42, and Venturi spray rod can be selectively activated according to the purge gas volume requirements and CO2 capture requirements to purge in a coordinated manner and efficiently remove the bubble barrier of the catalyst bed 2.

[0047] S3. Monitor the rich liquid flow rate and CO2 load in real time, and obtain the rich liquid feedforward signal based on the rich liquid design flow rate and CO2 load threshold; monitor the pressure difference change of catalyst bed 2 in real time to obtain the pressure difference feedback signal; superimpose the rich liquid feedforward signal and the pressure difference feedback signal, dynamically adjust the purging gas volume, determine the final value of the real-time purging gas volume, and purge the catalyst bed 2 with the final value of the real-time purging gas volume.

[0048] Based on preliminary experiments to eliminate bubbles, the baseline value for the purge gas flow rate was determined to be 10–15 mL / min. The purge gas flow rate of catalyst bed 2 was then dynamically adjusted based on the rich liquid flow rate and CO2 loading at the rich liquid inlet pipe 8 of the stripping column 1, as well as the pressure difference changes in catalyst bed 2.

[0049] 1. Monitor the rich liquid flow rate of the rich liquid inlet pipe 8 of the analyzer 1 in real time, and obtain the rich liquid feedforward signal based on the rich liquid design flow rate and the purge gas volume benchmark value, including:

[0050] A second flow meter 7 and an online CO2 analyzer are installed on the rich liquid inlet pipe 8 of the analytical tower 1 to monitor the rich liquid flow rate of the rich liquid inlet pipe 8 in real time. Based on the rich liquid design flow rate and the purge gas volume benchmark value, the first purge gas volume is determined, including:

[0051] When the rich liquid flow rate is greater than or equal to 80% of the rich liquid design flow rate, the first purging gas volume is 115-150% of the baseline value of the purging gas volume. For every 10% increase in the rich liquid flow rate, the first purging gas volume increases by 15% of the baseline value of the purging gas volume.

[0052] When 50% of the design flow rate of the rich liquid is less than the flow rate of the rich liquid and less than 80% of the design flow rate of the rich liquid, the first purge gas volume is the reference value of the purge gas volume.

[0053] When the rich liquid flow rate is ≤ 50% of the rich liquid design flow rate, the first purging gas volume is 30%~70% of the purging gas volume reference value. For every 10% decrease in the rich liquid flow rate, the first purging gas volume is reduced by 10% of the purging gas volume reference value.

[0054] 2. Monitor the CO2 load of the rich liquid inlet pipe 8 in real time using an online CO2 analyzer. Determine the second purge gas volume based on the CO2 load threshold and the purge gas volume benchmark value:

[0055] When the CO2 loading is ≥0.40 mol / mol, the second purge gas volume is 120%~150% of the purge gas volume baseline value;

[0056] When 0.25 mol / mol < CO2 loading < 0.40 mol / mol, the second purge gas volume is the baseline value for the purge gas volume;

[0057] When the CO2 loading is ≤0.25 mol / mol, the second purge gas volume is 50%~70% of the baseline purge gas volume.

[0058] The rich liquid feedforward signal is obtained based on the maximum value of the first purge gas volume and the second purge gas volume.

[0059] In some possible embodiments, before switching to CO2 tail gas to purge catalyst bed 2, the rich liquid flow rate and CO2 loading can be monitored in advance, and the purge gas volume can be adjusted in advance based on the purge gas volume benchmark value.

[0060] 3. Monitor the pressure difference change in catalyst bed 2 in real time, and dynamically adjust the blowing gas volume based on the rate of pressure difference surge, including:

[0061] Differential pressure transmitters are installed at both ends of the catalyst bed to monitor the rate of pressure surge in catalyst bed 2 in real time. Based on the purge gas volume reference value, the purge gas volume is dynamically adjusted to determine the third purge gas volume.

[0062] When the rate of pressure differential rise is ≥0.5 kPa / min and the duration is ≥1 min, the first step length is increased to obtain the third purge gas volume. The first step length is 10%~20% of the purge gas volume baseline value.

[0063] When the differential pressure recovery rate is ≤0.1 kPa / min, stop increasing the first step length and restore the purge gas volume to the baseline value.

[0064] 4. Monitor the absolute value of the pressure difference in catalyst bed 2 in real time, and dynamically adjust the purging gas volume based on the pressure difference reference value and the purging gas volume reference value to determine the fourth purging gas volume:

[0065] When the absolute value of the pressure difference is greater than or equal to 130% of the pressure difference reference value, the second step size is increased to obtain the fourth purge gas volume. The second step size is 20% to 30% of the purge gas volume reference value.

[0066] When the absolute value of the pressure difference is less than or equal to 105% of the pressure difference reference value, the purge gas volume is restored to the reference value at a rate of 5% / min.

[0067] The differential pressure feedback signal is obtained based on the maximum values ​​of the third and fourth purge gas volumes.

[0068] In some possible embodiments, the differential pressure reference value is 3~8 kPa.

[0069] 5. Superimpose the rich liquid feedforward signal and the differential pressure feedback signal, dynamically adjust the purging gas flow rate, determine the final value of the real-time purging gas flow rate, and use the final value of the real-time purging gas flow rate to purge the catalyst bed 2, including:

[0070] The rich liquid feedforward signal and the differential pressure feedback signal are superimposed to obtain the calculated value of the purge gas volume, and the final value of the real-time purge gas volume is determined. The final value of the real-time purge gas volume includes...

[0071] When the calculated purge air volume is greater than 150% of the purge air volume reference value, the final purge air volume is 150% of the purge air volume reference value, and an alarm signal is issued simultaneously.

[0072] When 20% of the purge gas volume baseline value ≤ the purge gas volume calculated value ≤ 150% of the purge gas volume baseline value, the final purge gas volume value is the purge gas volume calculated value.

[0073] When the calculated purge gas volume is less than 20% of the purge gas volume reference value, the final purge gas volume is 20% of the purge gas volume reference value, and the minimum protection gas volume is maintained.

[0074] During continuous operation, the DCS / PLC system automatically adjusts and executes the purge gas volume setpoint based on the method described in this embodiment. If the load is extremely low (e.g., rich liquid flow rate ≤ design flow rate × 30% and CO2 load ≤ 0.20 mol / mol), the control system automatically reduces the purge gas volume to 20%~30% of the purge gas volume reference value or maintains the minimum protective gas volume (nitrogen) to save gas consumption.

[0075] In some possible embodiments, CO2 exhaust gas is purged intermittently (purging for 1 minute and stopping for 5 minutes), reducing the total gas consumption by about 30%, which is suitable for systems where bubble formation is slow. CO2 exhaust gas is purged using pulse purging, which uses a solenoid valve to release high-pressure gas instantaneously (0.3~0.5 MPa, pulse width 0.1~0.5 s), using shock waves to desorb bubbles, resulting in even lower gas consumption.

[0076] In some possible embodiments, this method can also adjust the purging rate in segments according to the CO2 content of the flue gas at the absorber outlet (range 0~25%, accuracy ±1% FS). When the CO2 content is ≤8%, the purging gas rate is 30%~50% of the baseline purging gas rate; when the CO2 content is between 8% and 15%, the purging gas rate is 70%~100% of the baseline purging gas rate; when the CO2 content is ≥15%, the purging gas rate is 110%~150% of the baseline purging gas rate (not exceeding 150% of the baseline value, i.e., the value corresponding to 20 mL / min in the preliminary experiment of S0). This mapping relationship is established based on the quantitative experimental data of purging gas rate, bubble coverage, and desorption rate in the preliminary experiment of S0.

[0077] S4. After the reaction is complete, close the gas inlet pipe 3, shut off the amine liquid circulation, and stop the operation.

[0078] The shutdown procedure is the reverse of the startup procedure. Based on the S3 control logic, the purge gas volume is gradually reduced, and after confirming there is no risk of amine backflow, the purge gas pipeline valve is closed, and then the amine circulation is stopped.

[0079] This invention utilizes CO2 tail gas to remove bubbles from the catalyst surface. The entire purging process only needs to overcome the resistance of the pipeline and distributor (typically a pressure drop of 2-5 kPa), which can be achieved using the residual pressure at the top of the desorption tower 1, without the need for additional pressurization. The additional power consumption per ton of CO2 is less than 0.05 kWh, approximately 5% of that of mechanical defoaming methods. Due to the improved desorption efficiency, the reboiler temperature of the desorption tower 1 can be appropriately reduced (approximately 5-10°C), and the regeneration heat consumption per ton of CO2 can be reduced by 0.3-0.6 GJ.

[0080] The analytical tower device of this invention is simple, requiring only minor modifications to the existing analytical tower, resulting in low cost and easy operation. This invention employs active purging to eliminate bubble barriers in the catalyst bed, overcoming the drawbacks of existing technologies such as high energy consumption, complex equipment, difficult construction, and high operating costs. Eliminating bubbles on the catalyst surface using CO2 exhaust gas reduces long-term bubble coverage and localized overheating. Simultaneously, the shearing and scouring effect of the airflow is minimal, preventing significant wear on catalyst particles and extending catalyst lifespan.

[0081] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A desorption tower apparatus for eliminating bubble barriers, characterized in that, It includes a purging tower (1), a gas venting pipe (3), a first purging unit (4), and a second purging unit (5); The desorption tower (1) is equipped with a catalyst bed (2) for desorbing CO2 and supplying CO2 tail gas to the first purging assembly (4) and the second purging assembly (5); The first purging unit (4) is fixed to the inner wall of the desorption tower (1) and placed below the catalyst bed (2); one end of the second purging unit (5) is fixed to the inner wall of the desorption tower (1) and the other end extends into the catalyst bed (2); the first purging unit (1) and the second purging unit (5) are used to provide gas to strip the bubbles adhering to the catalyst surface; One end of the air intake pipe (3) is connected to the exhaust pipe of the analytical tower (1), and the other end extends into the interior of the analytical tower (1) and is connected to the first purging unit (4) and the second purging unit (5) respectively.

2. The desorption tower apparatus for eliminating bubble barriers according to claim 1, characterized in that, The first purging unit (4) is an annular tube assembly (41). The annular tube assembly (41) includes one or more annular tubes connected to the gas inlet tube (3). Each annular tube is arranged concentrically with the desorption tower (1) and placed 10-20 mm below the catalyst bed (2). The annular tube has multiple first openings on the side facing away from the catalyst bed.

3. The desorption tower device for eliminating bubble barriers in CO2 tail gas according to claim 1, characterized in that, The first purging unit (4) is a sintered plate (42) connected to the gas inlet pipe (3). The sintered plate (42) is horizontally placed 50~100 mm below the catalyst bed (2), and its sidewall is fixed to the inner wall of the desorption tower (1). The sintered plate (42) has a porous metal structure, and the porosity of the sintered plate (42) is 15%~40%.

4. The desorption tower apparatus for eliminating bubble barriers according to claim 1, characterized in that, The second purging assembly (5) includes multiple Venturi spray rods, one side of each Venturi spray rod is evenly distributed along the desorption tower (1), and the other side extends into the middle of the catalyst bed (2), and is connected to the gas inlet pipe (3) respectively.

5. The desorption tower apparatus for eliminating bubble barriers according to claim 1, characterized in that, The gas inlet pipe (3) is provided with a gas-liquid separator (9), a filter (10), a first flow meter (6) and a regulating valve (11) in sequence along the gas flow direction; The bottom of the gas-liquid separator (9) is connected to the rich liquid feed pipe (8) of the desorption tower (1) through the condensate return pipe (12); And / or, the surface of the catalyst bed (2) is provided with a differential pressure transmitter, and the rich liquid inlet pipe (8) of the desorption tower (1) is provided with a second flow meter (7) and a CO2 detection unit.

6. A method for eliminating bubble barriers using the desorption tower apparatus for eliminating bubble barriers according to any one of claims 1 to 5, characterized in that, include: Inert gas is introduced into the stripping tower (1) to start the amine liquid circulation; After the amine liquid circulation stabilizes, the inert gas is turned off and the gas inlet pipe (3) is opened. Based on the purging gas volume reference value, the catalyst bed (2) is purged. Real-time monitoring of rich liquid flow rate and CO2 load, and based on the rich liquid design flow rate and CO2 load threshold, a rich liquid feedforward signal is obtained; real-time monitoring of the pressure difference change of the catalyst bed (2) is obtained; the rich liquid feedforward signal and the pressure difference feedback signal are superimposed, the purge gas volume is dynamically adjusted, the real-time final value of the purge gas volume is determined, and the catalyst bed (2) is purged with the real-time final value of the purge gas volume. After the reaction is complete, close the gas inlet pipe (3), shut off the amine liquid circulation, and stop the operation.

7. The method for eliminating bubble barriers according to claim 1, characterized in that, The purge gas volume reference value is 10~15 mL / min.

8. The method for eliminating bubble barriers according to claim 6, characterized in that, The real-time monitoring of the rich solution flow rate and CO2 load, and the generation of a rich solution feedforward signal based on the rich solution design flow rate and CO2 load threshold, includes: Real-time monitoring of the rich liquid flow rate, and determination of the first purge gas volume based on the rich liquid design flow rate and purge gas volume benchmark values, including: When the rich liquid flow rate is greater than or equal to 80% of the rich liquid design flow rate, the first purging gas volume is 115-150% of the purging gas volume benchmark value. For every 10% increase in the rich liquid flow rate, the first purging gas volume increases by 15% of the purging gas volume benchmark value. When 50% of the design flow rate of the rich liquid is less than the flow rate of the rich liquid and less than 80% of the design flow rate of the rich liquid, the first purge gas volume is the reference value of the purge gas volume. When the rich liquid flow rate is ≤ 50% of the rich liquid design flow rate, the first purging gas volume is 30%~70% of the purging gas volume benchmark value. Among them, for every 10% decrease in the rich liquid flow rate, the first purging gas volume is reduced by 10% of the purging gas volume benchmark value. Real-time monitoring of CO2 load, and determination of the second purge gas volume based on CO2 load threshold and purge gas volume baseline: When the CO2 loading is ≥0.40 mol / mol, the second purge gas volume is 120%~150% of the purge gas volume baseline value; When 0.25 mol / mol < CO2 loading < 0.40 mol / mol, the second purge gas volume is the baseline value for the purge gas volume; When the CO2 loading is ≤0.25 mol / mol, the second purge gas volume is 50%~70% of the baseline purge gas volume. The rich liquid feedforward signal is obtained based on the maximum value of the first purge gas volume and the second purge gas volume.

9. The method for eliminating bubble barriers according to claim 8, characterized in that, The real-time monitoring of the pressure difference change in the catalyst bed (2) to obtain the pressure difference feedback signal includes: The rate of pressure surge in the catalyst bed (2) is monitored in real time. Based on the purge gas volume benchmark value, the purge gas volume is dynamically adjusted to determine the third purge gas volume. When the rate of pressure differential rise is ≥0.5 kPa / min and the duration is ≥1 min, the first step length is increased to obtain the third purge gas volume. The first step length is 10%~20% of the purge gas volume baseline value. When the differential pressure recovery rate is ≤0.1 kPa / min, stop increasing the first step length and restore the purge gas volume to the baseline value; The absolute value of the pressure difference in the catalyst bed (2) is monitored in real time, and the purge gas volume is dynamically adjusted based on the pressure difference reference value and the purge gas volume reference value to determine the fourth purge gas volume: When the absolute value of the pressure difference is greater than or equal to 130% of the pressure difference reference value, the second step size is increased to obtain the fourth purge gas volume. The second step size is 20% to 30% of the purge gas volume reference value. When the absolute value of the pressure difference is less than or equal to 105% of the pressure difference reference value, the purge gas volume is restored to the reference value at a rate of 5% / min. The differential pressure feedback signal is obtained based on the maximum values ​​of the third and fourth purge gas volumes.

10. The method for eliminating bubble barriers according to claim 10, characterized in that, The rich liquid feedforward signal and the differential pressure feedback signal are superimposed to dynamically adjust the purging gas flow rate, determine the final value of the real-time purging gas flow rate, and purge the catalyst bed (2) with the final value of the real-time purging gas flow rate, including: The rich liquid feedforward signal and the differential pressure feedback signal are superimposed to obtain the calculated purge gas volume value, and the final value of the real-time purge gas volume is determined. The determination of the final value of the real-time purge gas volume includes: When the calculated purge air volume is greater than 150% of the purge air volume reference value, the final purge air volume is 150% of the purge air volume reference value, and an alarm signal is issued simultaneously. When 20% of the purge gas volume baseline value ≤ the purge gas volume calculated value ≤ 150% of the purge gas volume baseline value, the final purge gas volume value is the purge gas volume calculated value. When the calculated purge air volume is less than 20% of the purge air volume reference value, the final purge air volume value is 20% of the purge air volume reference value. The catalyst bed (2) is purged based on the final value of the real-time purging gas volume.

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