Carbon dioxide absorption device and method

Abstract

The invention relates to the technical field, in particular to a carbon dioxide absorption device and method.The carbon dioxide absorption device comprises an absorption tower, an absorption liquid supply loop, a primary absorption liquid circulation loop and a controller; a smoke inlet is formed in the bottom end of the absorption tower body, a smoke outlet is formed in the top end of the absorption tower body, and the secondary absorption unit and the primary absorption unit are sequentially arranged in the absorption tower body from top to bottom; the second-stage absorption unit comprises a second liquid distributor, an ultrasonic nebulizer, a high-voltage electrostatic generator and a second-stage absorption layer which are sequentially arranged at intervals from top to bottom, and the absorption liquid supply loop is located outside the absorption tower body; the first-stage absorption unit comprises a first liquid collector, a positive electrode plate, a first liquid distributor and a first-stage absorption layer which are sequentially arranged at intervals from top to bottom, and a first-stage absorption liquid circulation loop is located outside the absorption tower body; the absorption efficiency of CO2 can be effectively improved, and amine escape is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon dioxide absorption, and in particular to a carbon dioxide absorption device and method. Background Art

[0002] As the main source of carbon emissions, high-emission industries such as thermal power generation and steel smelting are in urgent need of efficient and feasible carbon capture technology. At present, amine absorption technology has become the mainstream technology for large-scale low-concentration CO2 capture due to its high process maturity, complete material and equipment supply chain, and rich engineering application cases. This technology uses a solution system with amine compounds (such as methyldiethanolamine MDEA, diethanolamine DEA, etc.) as absorbents to capture and separate CO2 using gas-liquid phase change.

[0003] However, traditional amine absorption technology still faces the following key problems in engineering applications:

[0004] 1. Low mass transfer efficiency and large equipment size

[0005] In traditional spray absorption towers, the particle size of the absorption liquid is relatively large (usually 100-500μm), resulting in a small gas-liquid contact area, significant liquid film resistance, and a long CO2 mass transfer path with a low rate. In order to achieve the capture efficiency requirements, an absorption tower with a larger diameter and height (usually a tower diameter ≥10m and a tower height ≥30m) is required, which significantly increases equipment investment and floor space.

[0006] 2. Amine escape and environmental pollution risks

[0007] During the absorption-desorption cycle, the temperature of the flue gas increases after decarbonization (usually to 50-80°C), resulting in a decrease in solubility and carrying some unreacted amine components, degradation products and moisture into the subsequent system, causing amine loss, equipment corrosion, secondary pollution and increased operating costs.

[0008] In response to the above problems, researchers in this field have proposed a variety of improvement solutions, but there are still limitations:

[0009] Patent CN116850755A proposes to form an irregular liquid film by vibrating the packing layer with sonic waves. Although this can slightly increase the gas-liquid contact area and generate micro-turbulence, the mass transfer efficiency is limited because the particle size of the absorption liquid does not change, and the amine escape cannot be effectively suppressed.

[0010] Patent CN115350567A uses high-speed centrifugal separation to recover micro-droplets in flue gas. Although it can reduce amine loss, the centrifugal process consumes a lot of energy and has poor capture efficiency for droplets with a particle size of less than 10 μm.

[0011] Patent CN118543225B disrupts the flue gas flow field by rotating / moving the packing layer. Although it strengthens the gas-liquid collision contact, it requires a complex mechanical structure to support the movement of multiple layers of packing, has poor long-term operating reliability, and has limited improvement in mass transfer efficiency.

[0012] Patent CN116020256A utilizes pressure difference to form turbulence to prolong the gas-liquid contact time, but the mixer structure causes the pressure resistance of the absorption tower to increase, limiting its application under large flow conditions.

[0013] In summary, none of the existing technical solutions have broken through the core bottleneck of traditional amine absorption technology, that is, how to achieve the coordinated optimization of efficient mass transfer and low amine escape in a smaller equipment volume. With the urgent need for low-carbon transformation in thermal power, steel and other industries, the development of an amine absorption technology method with high absorption efficiency and compact equipment structure has become a technical problem that needs to be solved urgently in this field. Summary of the invention

[0014] The purpose of the present application is to provide a carbon dioxide absorption device and method that can effectively increase the amount of gas processed, improve the CO2 absorption efficiency and reduce amine escape.

[0015] To achieve the above-mentioned purpose, a carbon dioxide absorption device used in the present application comprises: an absorption tower, an absorption liquid supply circuit, a primary absorption liquid circulation circuit and a controller;

[0016] The absorption tower comprises: an absorption tower body, a primary absorption unit, and a secondary absorption unit. The bottom end of the absorption tower body is provided with a smoke inlet, the top end of the absorption tower body is provided with a smoke outlet, and the secondary absorption unit and the primary absorption unit are sequentially arranged in the absorption tower body from top to bottom;

[0017] The secondary absorption unit comprises a second liquid distributor, an ultrasonic atomizer, a high-voltage electrostatic generator and a secondary absorption layer which are sequentially arranged from top to bottom, the absorption liquid supply loop is located outside the absorption tower body, and the two ends of the absorption liquid supply loop are respectively a liquid inlet end and a liquid supply end, the liquid supply end of the absorption liquid supply loop is connected to the second liquid distributor, and the absorption liquid supply loop is provided with a secondary feed pump for pumping the absorption liquid of the absorption liquid supply loop from the liquid inlet end to the liquid supply end;

[0018] The primary absorption unit comprises a first liquid collector, a positive electrode plate, a first liquid distributor, and a primary absorption layer which are sequentially arranged from top to bottom. The primary absorption liquid circulation loop is located outside the absorption tower body, and the two ends of the primary absorption liquid circulation loop are a liquid inlet end and a liquid supply end, respectively. The liquid inlet end of the primary absorption liquid circulation loop is connected to the first liquid collector, and the liquid supply end is connected to the first liquid distributor. The primary absorption liquid circulation loop is provided with a primary feed pump for pumping the absorption liquid in the first liquid collector from the liquid inlet end to the liquid supply end.

[0019] The controller is electrically connected to the ultrasonic atomizer, the high-voltage electrostatic generator, the positive electrode plate, the primary feed pump and the secondary feed pump respectively.

[0020] As a preferred technical solution, a secondary cooler is further provided on the absorption liquid supply circuit, one end of the secondary cooler is connected to the secondary feed pump, and the other end is connected to the supply end of the absorption liquid supply circuit.

[0021] As a preferred technical solution, a primary cooler is further provided on the primary absorption liquid circulation loop, one end of the primary cooler is connected to the primary feed pump, and the other end is connected to the liquid supply end of the absorption liquid supply loop.

[0022] As a preferred technical solution, the carbon dioxide absorption device further includes a washing water supply circuit, and the absorption tower further includes an amine recovery unit.

[0023] The amine recovery unit includes a third liquid distributor, an amine recovery layer, and a second liquid collector which are arranged in sequence from top to bottom. The second liquid collector is used to store washing water. The washing water supply loop is located outside the absorption tower body, and the two ends of the washing water supply loop are respectively a liquid inlet end and a liquid supply end. The liquid inlet end of the washing water supply loop is connected to the second liquid collector, and the liquid supply end is connected to the third liquid distributor. The washing water supply loop is provided with a three-stage feed pump for pumping the washing water in the second liquid collector from the liquid inlet end to the liquid supply end.

[0024] As a preferred technical solution, a three-stage cooler is further provided on the washing water supply circuit, one end of the three-stage cooler is connected to the three-stage feed pump, and the other end is connected to the supply end of the washing water supply circuit.

[0025] As a preferred technical solution, the carbon dioxide absorption device also includes a washing water recovery loop, which is located outside the absorption tower body, and the two ends of the washing water recovery loop are respectively a liquid inlet end and a liquid supply end, the liquid inlet end of the washing water recovery loop is connected to the three-stage cooler, and the liquid supply end is connected to the liquid inlet end of the absorption liquid supply loop.

[0026] As a preferred technical solution, the carbon dioxide absorption device also includes a plurality of component monitoring devices, which are respectively arranged at the liquid inlet end of the absorption liquid supply circuit and the liquid inlet end of the washing water supply circuit, and are respectively used to monitor the absorption liquid, water and amine component content of the washing water in the absorption liquid supply circuit and the washing water supply circuit.

[0027] As a preferred technical solution, the carbon dioxide absorption device further includes a desorption tower, an absorption liquid desorption circuit, and an absorption liquid recovery circuit.

[0028] The desorption tower comprises a desorption tower body and a desorption unit, wherein a gas outlet is provided at the top of the desorption tower body, a liquid outlet is provided at the bottom of the desorption tower body, and the desorption unit is arranged in the desorption tower body;

[0029] The desorption unit includes a fourth liquid distributor, a secondary packing layer, a primary packing layer, and a third liquid collector which are arranged in sequence from top to bottom. The absorption liquid desorption circuit and the absorption liquid recovery circuit are respectively located outside the desorption tower body, and the two ends of the absorption liquid desorption circuit and the absorption liquid recovery circuit are respectively a liquid inlet end and a liquid supply end. The liquid inlet end of the absorption liquid desorption circuit is connected to the bottom of the absorption tower body, and the liquid supply end is connected to the fourth liquid distributor. The absorption liquid desorption circuit is provided with a four-stage feed pump for pumping the absorption liquid at the bottom of the absorption tower body from the liquid inlet end to the fourth liquid distributor. The liquid inlet end of the absorption liquid recovery circuit is connected to the bottom of the desorption tower body, and the liquid supply end is connected to the liquid inlet end of the absorption liquid supply circuit. The absorption liquid recovery circuit is provided with a five-stage feed pump for pumping the absorption liquid at the bottom of the desorption tower body from the bottom of the desorption tower body to the liquid inlet end of the absorption liquid supply circuit.

[0030] As a preferred technical solution, a heat exchanger is also provided on the absorption liquid desorption circuit. The heat exchanger is arranged between the four-stage feed pump and the fourth liquid distributor, and one end of the heat exchanger is connected to the liquid supply end of the absorption liquid desorption circuit, and the other end is connected to the liquid inlet end of the absorption liquid recovery circuit.

[0031] The present application also provides a carbon dioxide absorption method, which adopts the carbon dioxide absorption device as described above, including: a controller controls a primary feed pump, a secondary feed pump, a positive electrode plate, an ultrasonic atomizer and a high-voltage electrostatic generator to start, controls the primary feed pump to transport the absorption liquid from the liquid inlet end of the absorption liquid supply circuit to the liquid supply end of the absorption liquid supply circuit, controls the ultrasonic atomizer to atomize the absorption liquid, controls the high-voltage electrostatic generator to negatively charge the atomized absorption liquid, controls the positive electrode plate to make the negatively charged absorption liquid fall to the liquid inlet end of the primary absorption liquid circulation circuit, and controls the secondary feed pump to transport the absorption liquid from the liquid inlet end of the primary absorption liquid circulation circuit to the liquid supply end of the primary absorption liquid circulation circuit.

[0032] The carbon dioxide absorption device provided by the above technical solution has the following beneficial effects compared with the prior art:

[0033] 1. The ultrasonic atomizer is used to refine the particle size of the absorption liquid, which effectively increases the gas-liquid contact area and enhances the mass transfer efficiency; and the absorption liquid is charged with negative electricity through a high-voltage electrostatic generator. The negative charge can promote the protonated amine group (-NH3+) in the absorption liquid to transform to the unprotonated direction, making the absorption liquid more nucleophilic and easier to react chemically with CO2; the increase in absorption efficiency greatly increases the gas processing volume of the device, and more flue gas can be processed without increasing the size of the device and the circulation volume of the absorption liquid, thereby reducing cost investment and operating consumption.

[0034] 2. A primary absorption layer and a secondary absorption layer are set to form a multi-stage absorption structure, wherein the secondary absorption layer uses atomized charged absorption liquid, and the unsaturated absorption liquid is cooled and then refluxed to the primary absorption layer to continue the reaction, thereby realizing graded absorption and cascade utilization of the absorption liquid;

[0035] 3. The positive electrode plate is used to make the negatively charged absorption liquid flow downward under the combined effect of Coulomb force and gravity, which effectively reduces the escape of amines. The amine recovery unit is set up to spray washing water to recover the amine components, degradation products and moisture in the decarbonized flue gas, which further reduces the escape of amines and avoids pollution to the environment.

[0036] 4. Each functional unit is connected through pipes and valves to form a closed circulation system, which effectively reduces the equipment's footprint and operational complexity. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic diagram of the structure of the present invention;

[0038] Wherein: 1. absorption tower; 11. absorption tower body; 110. smoke inlet; 111. smoke outlet; 12. primary absorption unit; 120. first liquid collector; 121. plate with positive electrode; 122. first liquid distributor; 123. primary absorption layer; 13. secondary absorption unit; 130. second liquid distributor; 131. ultrasonic atomizer; 132. high voltage electrostatic generator; 133. secondary absorption layer;

[0039] 2. Absorption liquid supply circuit; 21. Secondary feed pump; 22. Secondary cooler; 23. Liquid storage tank; 24. Water replenisher; 25. Amine replenisher;

[0040] 3. Primary absorption liquid circulation loop; 31. Primary feed pump; 32. Primary cooler;

[0041] 4. Amine recovery unit; 41. Third liquid distributor; 42. Amine recovery layer; 43. Second liquid collector;

[0042] 5. Washing water supply circuit; 51. Three-stage feed pump; 52. Three-stage cooler;

[0043] 6. Washing water recovery circuit;

[0044] 7. Component monitoring device;

[0045] 8. desorption tower; 80. desorption tower body; 81. fourth liquid distributor; 82. secondary packing layer; 83. primary packing layer; 84. third liquid collector; 85. gas outlet; 86. reboiler;

[0046] 9. Absorption liquid desorption circuit; 91. Four-stage feed pump; 92. Heat exchanger;

[0047] 10. Absorption liquid recovery circuit; 101. Five-stage feed pump. DETAILED DESCRIPTION

[0048] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0049] In the description of the present application, it should be understood that the terms "front", "rear", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, in the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0050] See also Figure 1 , a carbon dioxide absorption device provided in an embodiment of the present application, comprising: an absorption tower 1, an absorption liquid supply loop 2, a primary absorption liquid circulation loop 3 and a controller;

[0051] The absorption tower 1 comprises: an absorption tower body 11, a primary absorption unit 12, and a secondary absorption unit 13. The bottom end of the absorption tower body 11 is provided with a smoke inlet 110, and the top end of the absorption tower body 11 is provided with a smoke outlet 111. The secondary absorption unit 13 and the primary absorption unit 12 are sequentially arranged in the absorption tower body 11 from top to bottom.

[0052] The secondary absorption unit 13 comprises a second liquid distributor 130, an ultrasonic atomizer 131, a high-voltage electrostatic generator 132 and a secondary absorption layer 133 which are sequentially arranged from top to bottom. The absorption liquid supply loop 2 is located outside the absorption tower body 11, and the two ends of the absorption liquid supply loop 2 are respectively a liquid inlet end and a liquid supply end. The liquid supply end of the absorption liquid supply loop 2 is connected to the second liquid distributor 130. The absorption liquid supply loop 2 is provided with a secondary feed pump 21 for pumping the absorption liquid of the absorption liquid supply loop 2 from the liquid inlet end to the liquid supply end.

[0053] The primary absorption unit 12 comprises a first liquid collector 120, a positive electrode plate 121, a first liquid distributor 122, and a primary absorption layer 123 which are sequentially arranged from top to bottom. The primary absorption liquid circulation loop 3 is located outside the absorption tower body 11, and the two ends of the primary absorption liquid circulation loop 3 are respectively a liquid inlet end and a liquid supply end. The liquid inlet end of the primary absorption liquid circulation loop 3 is connected to the first liquid collector 120, and the liquid supply end is connected to the first liquid distributor 122. The primary absorption liquid circulation loop 3 is provided with a primary feed pump 31 for pumping the absorption liquid in the first liquid collector 120 from the liquid inlet end to the liquid supply end.

[0054] The controller is electrically connected to the ultrasonic atomizer 131 , the high-voltage electrostatic generator 132 , the positive electrode plate 121 , the primary feed pump 31 and the secondary feed pump 21 , respectively.

[0055] In this embodiment, the spraying of the absorption liquid must be completed first. The controller controls the ultrasonic atomizer 131, the high-voltage electrostatic generator 132, the positive electrode plate 121, the primary feed pump 31 and the secondary feed pump 21 to start. The secondary feed pump 21 extracts the absorption liquid from the liquid storage tank 23, enters through the liquid inlet of the absorption liquid supply circuit 2 and transports it to the liquid outlet. Then the absorption liquid enters the second liquid distributor 130, and is sprayed by the second liquid distributor 130 to the ultrasonic atomizer 131 for atomization. After atomization, The absorption liquid enters the high-voltage electrostatic generator 132 and is negatively charged, and the negatively charged absorption liquid then enters the secondary absorption layer 133; the absorption liquid in the secondary absorption layer 133 falls into the first liquid collector 120 under the action of gravity and the positive electrode plate 121, and the primary feed pump 31 extracts the absorption liquid from the first liquid collector 120, enters through the liquid inlet of the primary absorption liquid circulation loop 3 and transports it to the liquid outlet, and then the absorption liquid enters the first liquid distributor 122, and is sprayed into the primary absorption layer 123 by the first liquid distributor. Then, when the primary absorption layer 123 and the secondary absorption layer 133 are full of absorption liquid, the pretreated flue gas is introduced at the smoke inlet 110 of the absorption tower 1, and the flue gas enters the primary absorption layer 123 and the secondary absorption layer 133 in turn to react with the absorption liquid, and the absorption liquid absorbs CO2 in the flue gas, and the flue gas after two absorptions is discharged through the smoke outlet 111 at the top of the absorption tower body.

[0056] On the one hand, the device refines the particle size of the absorption liquid by setting an ultrasonic atomizer 131, significantly increasing the surface area of ​​the absorption liquid, and the fine absorption liquid particles have a shorter diffusion path, small mass transfer resistance, and a higher absorption rate, thereby improving the utilization rate of the absorption liquid. The atomized absorption liquid is more evenly distributed in the tower, reducing the situation of partial gas-liquid flow short circuit or dead zone that may exist in the absorption tower 1 of the traditional spraying; on the other hand, a high-voltage electrostatic generator 132 is set to make the atomized absorption liquid negatively charged, and a positive electrode plate 121 is set under the first liquid collector 120, so that the negatively charged absorption liquid flows downward rapidly under the superposition of Coulomb force and gravity, effectively reducing the escape of amines. And the negative charge can promote the transformation of the protonated amine group in the absorption liquid to the unprotonated direction, so the negatively charged absorption liquid has a higher nucleophilicity and is more likely to react chemically with CO2, thereby having a faster reaction speed and higher absorption efficiency.

[0057] Furthermore, the absorption liquid supply loop 2 is also provided with a secondary cooler 22, one end of which is connected to the secondary feed pump 21, and the other end is connected to the liquid supply end of the absorption liquid supply loop 2. At the same time, the primary absorption liquid circulation loop 3 is also provided with a primary cooler 32, one end of which is connected to the primary feed pump 31, and the other end is connected to the liquid supply end of the absorption liquid supply loop 2. Coolers are respectively provided in the absorption liquid supply loop 2 and the primary absorption liquid circulation loop 3. Before the device is started, the predetermined temperature of the coolant is set. After the device is started, the coolant entering the two loops can be cooled by the cooler to reduce its temperature to the predetermined temperature, thereby further improving the absorption efficiency of the coolant for CO2 in the high-temperature flue gas.

[0058] Furthermore, the carbon dioxide absorption device further comprises a washing water supply circuit 5, and the absorption tower 1 further comprises an amine recovery unit 4.

[0059] The amine recovery unit 4 includes a third liquid distributor 41, an amine recovery layer 42, and a second liquid collector 43 which are arranged in sequence from top to bottom. The second liquid collector 43 is used to store washing water. The washing water supply loop 5 is located outside the absorption tower body 11, and the two ends of the washing water supply loop 5 are respectively a liquid inlet end and a liquid supply end. The liquid inlet end of the washing water supply loop 5 is connected to the second liquid collector 43, and the liquid supply end is connected to the third liquid distributor 41. The washing water supply loop 5 is provided with a three-stage feed pump 51 for pumping the washing water in the second liquid collector 43 from the liquid inlet end to the liquid supply end.

[0060] In this embodiment, an amine recovery unit 4 is arranged in the absorption tower 1, and the flue gas after decarbonization is cooled by water washing, and the amine substances and water carried in the flue gas are recovered, thereby reducing amine escape and reducing environmental pollution. The specific operation is as follows: before the device is started, an appropriate amount of washing water is added to the second liquid collector 43. After the device is started, the three-stage feed pump 51 continuously extracts washing water from the second liquid collector 43, and transports the washing water to the third liquid distributor 41 through the washing water supply circuit 5. The washing water is sprayed to the amine recovery layer 42 by the third liquid distributor 41. When the flue gas that has undergone secondary absorption enters the amine recovery layer 42, the flue gas reacts with the washing water, cools the flue gas, and recovers the amine substances and water carried in the flue gas. The flue gas after amine recovery is discharged through the smoke outlet 111 at the top of the absorption tower body.

[0061] Furthermore, the washing water supply loop 5 is provided with a tertiary cooler 52, one end of which is connected to the tertiary feed pump 51, and the other end is connected to the supply end of the washing water supply loop 5. The tertiary cooler 52 is provided to cool the washing water, so that the washing water can further cool the flue gas, increase the reaction rate with the flue gas, and increase the recovery efficiency of the amine substance and water carried in the flue gas.

[0062] In addition, in order to detect the CO2 absorption efficiency of the device and the effect of preventing amine escape, the applicant compared the operating effects under different working conditions. The results are as follows:

[0063] Table 1

[0064]

[0065] It can be seen from Table 1 that as the temperature of the pretreated flue gas increases and the CO2 concentration in the flue gas at the smoke inlet 110 increases, the CO2 absorption rate is always higher than 90%, and the amine concentration in the flue gas at the smoke outlet 111 is always lower than ppm. In traditional technology, the CO2 absorption rate is generally around 80% to 90%, and the amine concentration in the flue gas at the smoke outlet 111 is generally around 10ppm to 20ppm. It can be seen that compared with traditional technology, Example 1 of the present application can effectively increase the absorption rate of carbon dioxide and reduce amine escape.

[0066] Furthermore, the carbon dioxide absorption device further comprises a washing water recovery loop 6, the washing water recovery loop 6 is located outside the absorption tower body 11, and the two ends of the washing water recovery loop 6 are respectively a liquid inlet end and a liquid supply end, the liquid inlet end of the washing water recovery loop 6 is connected to the tertiary cooler 52, and the liquid supply end is connected to the liquid inlet end of the absorption liquid supply loop 2. By recovering the washing water after reacting with the flue gas, the recovered washing water is rich in amine components and can supplement the absorption liquid.

[0067] Furthermore, the carbon dioxide absorption device also includes a plurality of component monitoring devices 7, which are respectively arranged at the liquid inlet end of the absorption liquid supply loop 2 and the liquid inlet end of the washing water supply loop 5, and are respectively used to monitor the absorption liquid, water and amine component content of the washing water on the absorption liquid supply loop 2 and the washing water supply loop 5.

[0068] In this embodiment, the present application further provides a water replenisher 24 and an amine replenisher 25 at the liquid storage tank 23 to replenish water and amine components to the absorption liquid in the liquid storage tank 23, and further provides a water replenisher 24 outside the absorption tower 1 and connected to the second liquid collector 43 to replenish water to the washing water in the second liquid collector 43. When the component monitoring device 7 detects that the components (water and amine components) of the absorption liquid entering the liquid inlet end of the absorption liquid supply loop 2 or the washing water entering the liquid inlet end of the washing water supply loop 5 are insufficient, the controller controls the corresponding water replenisher 24 and amine replenisher 25 to replenish the components to ensure the effect of the absorption liquid and the washing water.

[0069] Furthermore, the carbon dioxide absorption device further comprises a desorption tower 8, an absorption liquid desorption circuit 9, and an absorption liquid recovery circuit 10.

[0070] The desorption tower 8 comprises a desorption tower body 80 and a desorption unit. The top of the desorption tower body 80 is provided with a gas outlet 85, the bottom of the desorption tower body 80 is provided with a liquid outlet, and the desorption unit is arranged in the desorption tower body 80;

[0071] The desorption unit comprises a fourth liquid distributor 81, a secondary packing layer 82, a primary packing layer 83, and a third liquid collector 84 which are arranged in sequence from top to bottom. The absorption liquid desorption circuit 9 and the absorption liquid recovery circuit 10 are respectively located outside the desorption tower body 80, and the two ends of the absorption liquid desorption circuit 9 and the absorption liquid recovery circuit 10 are respectively a liquid inlet end and a liquid supply end. The liquid inlet end of the absorption liquid desorption circuit 9 is connected to the bottom of the absorption tower body 11, and the liquid supply end is connected to the fourth liquid distributor 81. The absorption liquid desorption circuit 9 is provided with a four-stage feed pump 91 for pumping the absorption liquid at the bottom of the absorption tower body 11 from the liquid inlet end to the fourth liquid distributor 81, the liquid inlet end of the absorption liquid recovery circuit 10 is connected to the bottom of the desorption tower body 80, and the liquid supply end is connected to the liquid inlet end of the absorption liquid supply circuit 2, and the absorption liquid recovery circuit 10 is provided with a five-stage feed pump 101 for pumping the absorption liquid at the bottom of the desorption tower body 80 from the bottom of the desorption tower body 80 to the liquid inlet end of the absorption liquid supply circuit 2.

[0072] In this embodiment, the desorption unit further includes a reboiler 86 connected between the third liquid collector 84 and the bottom of the desorption tower body 80 . The absorption liquid falling into the bottom of the absorption tower body 11 has a high CO2 concentration and is called "rich liquid". The four-stage feed pump 91 extracts the "rich liquid" from the bottom of the absorption tower body 11 and transports it to the desorption tower body 80 through the absorption liquid desorption circuit 9. After being sprayed by the fourth liquid distributor 81, the "rich liquid" enters the secondary packing layer 82 and the primary packing layer 83 in turn, and finally falls into the third liquid collector 84, and then flows into the reboiler 86 to be heated to a certain temperature. After heating, the CO2 in the "rich liquid" is separated, and the separated CO2 forms bubbles and gradually rises to exchange heat with the "rich liquid" that subsequently enters the absorption tower body 11 in the primary packing layer 83 and the secondary packing layer 82 in turn, until the separated CO2 rises to the top of the desorption tower body 80. By arranging a gas-liquid separation device at the top of the desorption tower body 80, CO2 can be separated from a small amount of absorbent droplets that may be carried to obtain relatively pure CO2, which can be used for subsequent compression, storage or utilization processes. The "rich liquid" from which CO2 is separated becomes "lean liquid", and the five-stage feed pump 101 draws the "lean liquid" from the bottom of the desorption tower body 80 and transports it to the liquid storage tank 23 through the absorption liquid recovery loop 10 to complete the recovery and utilization of the absorption liquid and reduce the loss of the absorption liquid.

[0073] Furthermore, a heat exchanger 92 is provided on the absorption liquid desorption circuit 9, and the heat exchanger 92 is provided between the four-stage feed pump 91 and the fourth liquid distributor 81, and one end of the heat exchanger 92 is connected to the liquid supply end of the absorption liquid desorption circuit 9, and the other end is connected to the liquid inlet end of the absorption liquid recovery circuit 10. The heat exchanger 92 can exchange heat between the "rich liquid" extracted from the bottom of the absorption tower body 11 by the four-stage feed pump 91 and the "lean liquid" extracted from the bottom of the desorption tower body 80 by the five-stage feed pump 101, so as to increase the temperature of the "rich liquid" entering the desorption tower body 80 and reduce the temperature of the "lean liquid" entering the liquid storage tank 23.

[0074] The present application also provides a carbon dioxide absorption method, which adopts the carbon dioxide absorption device as described above, including: a controller controls a primary feed pump 31, a secondary feed pump 21, a positive electrode plate 121, an ultrasonic atomizer 131 and a high-voltage electrostatic generator 132 to start, controls the primary feed pump 31 to transport the absorption liquid from the liquid inlet end of the absorption liquid supply loop 2 to the liquid supply end of the absorption liquid supply loop 2, controls the ultrasonic atomizer 131 to atomize the absorption liquid, controls the high-voltage electrostatic generator 132 to negatively charge the atomized absorption liquid, controls the positive electrode plate 121 to make the negatively charged absorption liquid fall to the liquid inlet end of the primary absorption liquid circulation loop 3, and controls the secondary feed pump 21 to transport the absorption liquid from the liquid inlet end of the primary absorption liquid circulation loop 3 to the liquid supply end of the primary absorption liquid circulation loop 3. This method can be used to absorb the pretreated flue gas twice, and the atomized absorption liquid can better absorb the flue gas, effectively improve the absorption efficiency of CO2 in the flue gas, reduce the reaction time with the flue gas, and effectively prevent amine escape after the absorption liquid reacts with the flue gas.

[0075] In summary, the carbon dioxide absorption device and method provided in this embodiment can not only effectively increase the gas-liquid contact area and enhance the mass transfer efficiency, but also realize the graded absorption of carbon dioxide to improve the absorption efficiency. It also recovers the amine components, degradation products and moisture in the decarbonized flue gas through water washing, effectively reduces amine escape and avoids pollution to the environment. The overall device forms a closed circulation system, which effectively reduces the equipment's footprint and operational complexity.

[0076] This specification discloses the present application with reference to the accompanying drawings, and also enables those skilled in the art to implement the present application, including making and using any device or system, using suitable materials, and using any combined method. The scope of the present application is defined by the technical solution for protection, and includes other examples that occur to those skilled in the art. As long as such other examples include structural elements that are not different from the literal language of the technical solution for protection, or such other examples contain equivalent structural elements that are not substantially different from the literal language of the technical solution for protection, such other examples should be considered to be within the scope of protection determined by the technical solution for protection of the present application.

Claims

1. A carbon dioxide absorption device, characterized in that: include: Absorption tower, absorption liquid supply loop, primary absorption liquid circulation loop and controller; The absorption tower comprises: an absorption tower body, a primary absorption unit, and a secondary absorption unit. The bottom end of the absorption tower body is provided with a smoke inlet, the top end of the absorption tower body is provided with a smoke outlet, and the secondary absorption unit and the primary absorption unit are sequentially arranged in the absorption tower body from top to bottom; The secondary absorption unit comprises a second liquid distributor, an ultrasonic atomizer, a high-voltage electrostatic generator and a secondary absorption layer which are sequentially arranged from top to bottom, the absorption liquid supply loop is located outside the absorption tower body, and the two ends of the absorption liquid supply loop are respectively a liquid inlet end and a liquid supply end, the liquid supply end of the absorption liquid supply loop is connected to the second liquid distributor, and the absorption liquid supply loop is provided with a secondary feed pump for pumping the absorption liquid of the absorption liquid supply loop from the liquid inlet end to the liquid supply end; The primary absorption unit comprises a first liquid collector, a positive electrode plate, a first liquid distributor, and a primary absorption layer which are sequentially arranged from top to bottom. The primary absorption liquid circulation loop is located outside the absorption tower body, and the two ends of the primary absorption liquid circulation loop are a liquid inlet end and a liquid supply end, respectively. The liquid inlet end of the primary absorption liquid circulation loop is connected to the first liquid collector, and the liquid supply end is connected to the first liquid distributor. The primary absorption liquid circulation loop is provided with a primary feed pump for pumping the absorption liquid in the first liquid collector from the liquid inlet end to the liquid supply end. The controller is electrically connected to the ultrasonic atomizer, the high-voltage electrostatic generator, the positive electrode plate, the primary feed pump and the secondary feed pump respectively.

2. The carbon dioxide absorption device according to claim 1, characterized in that The absorption liquid supply circuit is also provided with a secondary cooler, one end of the secondary cooler is connected to the secondary feed pump, and the other end is connected to the supply end of the absorption liquid supply circuit.

3. The carbon dioxide absorption device according to claim 1, characterized in that The primary absorption liquid circulation loop is also provided with a primary cooler, one end of the primary cooler is connected to the primary feed pump, and the other end is connected to the liquid supply end of the absorption liquid supply loop.

4. The carbon dioxide absorption device according to claim 1, characterized in that It also includes a washing water supply loop, and the absorption tower also includes an amine recovery unit. The amine recovery unit includes a third liquid distributor, an amine recovery layer, and a second liquid collector which are arranged in sequence from top to bottom. The second liquid collector is used to store washing water. The washing water supply loop is located outside the absorption tower body, and the two ends of the washing water supply loop are respectively a liquid inlet end and a liquid supply end. The liquid inlet end of the washing water supply loop is connected to the second liquid collector, and the liquid supply end is connected to the third liquid distributor. The washing water supply loop is provided with a three-stage feed pump for pumping the washing water in the second liquid collector from the liquid inlet end to the liquid supply end.

5. The carbon dioxide absorption device according to claim 4, characterized in that The washing water supply circuit is also provided with a three-stage cooler, one end of the three-stage cooler is connected to the three-stage feed pump, and the other end is connected to the supply end of the washing water supply circuit.

6. The carbon dioxide absorption device according to claim 5, characterized in that It also includes a washing water recovery loop, which is located outside the absorption tower body, and the two ends of the washing water recovery loop are respectively a liquid inlet end and a liquid supply end, the liquid inlet end of the washing water recovery loop is connected to the three-stage cooler, and the liquid supply end is connected to the liquid inlet end of the absorption liquid supply loop.

7. The carbon dioxide absorption device according to claim 6, characterized in that It also includes a plurality of component monitoring devices, which are respectively arranged at the liquid inlet end of the absorption liquid supply circuit and the liquid inlet end of the washing water supply circuit, and are respectively used to monitor the absorption liquid, water and amine component content of the washing water in the absorption liquid supply circuit and the washing water supply circuit.

8. The carbon dioxide absorption device according to any one of claims 1 to 7, characterized in that: It also includes a desorption tower, an absorption liquid desorption circuit, and an absorption liquid recovery circuit. The desorption tower comprises a desorption tower body and a desorption unit, wherein a gas outlet is provided at the top of the desorption tower body, a liquid outlet is provided at the bottom of the desorption tower body, and the desorption unit is arranged in the desorption tower body; The desorption unit includes a fourth liquid distributor, a secondary packing layer, a primary packing layer, and a third liquid collector which are arranged in sequence from top to bottom. The absorption liquid desorption circuit and the absorption liquid recovery circuit are respectively located outside the desorption tower body, and the two ends of the absorption liquid desorption circuit and the absorption liquid recovery circuit are respectively a liquid inlet end and a liquid supply end. The liquid inlet end of the absorption liquid desorption circuit is connected to the bottom of the absorption tower body, and the liquid supply end is connected to the fourth liquid distributor. The absorption liquid desorption circuit is provided with a four-stage feed pump for pumping the absorption liquid at the bottom of the absorption tower body from the liquid inlet end to the fourth liquid distributor. The liquid inlet end of the absorption liquid recovery circuit is connected to the bottom of the desorption tower body, and the liquid supply end is connected to the liquid inlet end of the absorption liquid supply circuit. The absorption liquid recovery circuit is provided with a five-stage feed pump for pumping the absorption liquid at the bottom of the desorption tower body from the bottom of the desorption tower body to the liquid inlet end of the absorption liquid supply circuit.

9. The carbon dioxide absorption device according to claim 8, characterized in that A heat exchanger is also provided on the absorption liquid desorption circuit. The heat exchanger is arranged between the four-stage feed pump and the fourth liquid distributor, and one end of the heat exchanger is connected to the liquid supply end of the absorption liquid desorption circuit, and the other end is connected to the liquid inlet end of the absorption liquid recovery circuit.

10. A method for absorbing carbon dioxide, characterized in that: A carbon dioxide absorption device according to any one of claims 1 to 9, comprising: The controller controls the start-up of the primary feed pump, the secondary feed pump, the positive electrode plate, the ultrasonic atomizer and the high-voltage electrostatic generator, controls the primary feed pump to transport the absorption liquid from the liquid inlet end of the absorption liquid supply circuit to the liquid supply end of the absorption liquid supply circuit, controls the ultrasonic atomizer to atomize the absorption liquid, controls the high-voltage electrostatic generator to negatively charge the atomized absorption liquid, controls the positive electrode plate to make the negatively charged absorption liquid fall to the liquid inlet end of the primary absorption liquid circulation circuit, and controls the secondary feed pump to transport the absorption liquid from the liquid inlet end of the primary absorption liquid circulation circuit to the liquid supply end of the primary absorption liquid circulation circuit.

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