Enhanced carbon dioxide trapping system and decarburization method thereof

Abstract

The invention provides an enhanced carbon dioxide trapping system and a decarburization method thereof. The system comprises a multi-stage enhanced reaction tower, and the multi-stage enhanced reaction tower is provided with a flue gas pipeline, a rich liquid feed port and a discharge port; a strengthening unit is arranged in the multi-stage strengthening reaction tower, a circulating pipeline is further arranged on the outer side of the multi-stage strengthening reaction tower, and a circulating pump and a flow control valve are sequentially arranged on the circulating pipeline. According to the enhanced carbon dioxide capture system, by means of the mode that the multiple stages of enhanced reaction towers and the circulating pipeline are combined, CO2 existing in flue gas can be efficiently captured, meanwhile, regeneration energy consumption is greatly reduced, and the CO2 absorption rate can be well increased.

Description

Technical Field

[0001] The present invention belongs to the technical field of flue gas purification, and in particular relates to an enhanced carbon dioxide capture system and a decarbonization method thereof. Background Art

[0002] In the field of carbon capture, decarbonization technology is widely used. Nowadays, carbon capture technology is used to capture and store carbon dioxide, thereby effectively reducing the content of carbon dioxide in the atmosphere and combating climate change. Direct capture of carbon dioxide can substantially reduce the content of carbon dioxide in the atmosphere to form negative emissions, reduce greenhouse gas emissions, and promote energy transformation and sustainable development. Therefore, achieving negative carbon emissions is a very critical technology.

[0003] However, most of today's carbon capture technologies are costly, including the high cost of building and operating carbon capture facilities, and the carbon capture process itself consumes a lot of energy, especially when using chemical absorption, which requires a lot of energy to provide heat and pressure. Even so, when consuming a lot of energy to capture carbon dioxide, the capture efficiency that can be achieved is also limited. Most current carbon capture methods can achieve low capture efficiency. Therefore, how to achieve efficient capture of carbon dioxide while reducing the energy consumption required for the decarbonization process is the key to carbon capture technology.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The first purpose of the present invention is to provide an enhanced carbon dioxide capture system, which can efficiently capture CO2 present in flue gas while greatly reducing regeneration energy consumption and greatly improving the CO2 absorption rate by combining a multi-stage enhanced reaction tower and a circulation pipeline.

[0006] The second object of the present invention is to provide a decarbonization method, which uses the enhanced carbon dioxide capture system provided by the present invention to efficiently capture carbon dioxide in flue gas using an absorbent, thereby greatly improving the capture efficiency of carbon dioxide.

[0007] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted: A reinforced carbon dioxide capture system comprises a multi-stage reinforced reaction tower, on which a flue gas pipeline, a rich liquid feed port and a discharge port are arranged; an enhanced unit is arranged inside the multi-stage reinforced reaction tower, and a circulation pipeline is also arranged outside the multi-stage reinforced reaction tower, on which a circulation pump and a flow control valve are arranged in sequence.

[0008] In the system of the present invention, it mainly realizes the enhanced capture of carbon dioxide through a multi-stage enhanced reaction tower, wherein an enhanced unit is arranged in the multi-stage enhanced reaction tower to increase the load of the reaction liquid introduced into the reaction tower, which can effectively promote the gas-liquid mass transfer process and improve the removal rate of CO2 in the flue gas. In addition, the reaction liquid is deflected through an external circulation pipeline, so that the reaction liquid entering from the top of the enhanced reaction tower is re-input from the bottom of the tower to the top of the tower through the setting of the circulation pipeline when it reaches the bottom of the tower, which can well increase the reaction time of the reaction liquid in the enhanced reaction tower and further improve the removal rate of CO2 in the flue gas. In addition, a flow control valve is arranged on the circulation pipeline to control the flow of the rich liquid flowing into the enhanced reaction tower so that it is at 2m 3 / h-8m 3 / h flow rate, when the reaction liquid flows into the enhanced reaction tower, the removal of carbon dioxide in the flue gas can achieve excellent results. This is because in order to achieve enhanced absorption of carbon dioxide, the present invention requires nearly saturated rich liquid and flue gas to flow into the enhanced reaction tower at a certain flow rate, and the flue gas is broken into microbubbles after being processed by the enhanced unit, so that the flue gas broken into microbubbles and the rich liquid form a stable gas-liquid mixture. In this way, the load of the reaction liquid is greatly increased, and the removal of CO2 is improved. If the flow rate is too low, the reaction system in the enhanced reaction tower will be saturated prematurely, affecting the capture of carbon dioxide in the flue gas; if the flow rate is too fast, the load in the reaction liquid will be too low, so that the reaction liquid cannot absorb carbon dioxide in the flue gas, thereby affecting the removal effect of carbon dioxide.

[0009] Preferably, as a further implementable solution, the multi-stage enhanced reaction tower is a two-stage enhanced reaction tower, wherein the two-stage enhanced reaction tower comprises a first-stage enhanced reaction tower and a second-stage enhanced reaction tower.

[0010] Preferably, as a further implementable scheme, a first enhancement unit is arranged at the top of the first-stage enhanced reaction tower, and a disc-shaped duct is arranged below the first enhancement unit; the rich liquid feed port and the flue gas duct are arranged in sequence at the top of the first-stage enhanced reaction tower, and a discharge port and a circulation feed port are respectively arranged on both sides of the first-stage enhanced reaction tower.

[0011] In the enhanced carbon dioxide capture system of the present invention, a two-stage enhanced reaction tower is mainly used, wherein the two-stage enhanced reaction tower includes a first-stage enhanced reaction tower and a second-stage enhanced reaction tower. In the first-stage enhanced reaction tower of the present invention, the raw material mainly enters through the rich liquid feed port and the flue gas pipeline arranged at the top of the first-stage enhanced reaction tower, and then the flue gas is broken into microbubbles through the first enhanced unit arranged at the top of the first-stage enhanced reaction tower, and then mixed with the rich liquid to form a stable gas-liquid mixture. The treated gas-liquid mixture, i.e., the reaction liquid, has a higher load capacity, which can improve the capture capacity of the reaction liquid for carbon dioxide in the flue gas, and further remove the carbon dioxide in the flue gas. In addition, the present invention further increases the reaction time of the reaction liquid in the first-stage enhanced reaction tower by arranging a disc-shaped conduit below the first enhanced unit. In the process of the reaction liquid running from top to bottom, the descending speed of the reaction liquid will gradually decrease until it stops after running to the bottom of the reactor, and the gas phase in the reaction liquid will gradually rise in the liquid phase under the influence of buoyancy, and the gas phase in the reaction liquid can be arranged The residence time of the gas phase in the liquid phase is longer, thereby further improving the removal of carbon dioxide in the flue gas.

[0012] Preferably, as a further implementable solution, the circulation pipeline is arranged outside the first-stage enhanced reaction tower, and the circulation pump is connected to the circulation feed inlet.

[0013] In the present invention, the first-stage enhanced reaction tower and the circulation pipeline are combined to allow the reaction liquid to flow in from the top of the enhanced reaction tower. The reaction time of the enhanced reaction tower is increased through the disc-shaped conduit, and the reaction liquid can reach the bottom of the enhanced reaction tower from top to bottom. Subsequently, the reaction liquid reaching the bottom is introduced from the top of the reaction tower again through the circulation pipeline, thereby further increasing the reaction time of the reaction liquid, making the decarbonization reaction more sufficient and thorough, and further improving the removal of carbon dioxide in the flue gas. The present invention introduces the reaction liquid from the top of the enhanced reaction tower, so that the reaction liquid can move from top to bottom in the reaction tower. As the reaction liquid descends to the bottom of the reaction tower, its speed will decrease accordingly until it stops. Since the reaction liquid moves from top to bottom, the gas phase in the reaction liquid will be affected by buoyancy and gradually rise in the liquid phase. During the rising process, the rate of the gas phase gradually decreases. Through such an arrangement, the residence time of the gas phase in the liquid phase can be increased, thereby improving the removal effect of carbon dioxide. Therefore, the present invention greatly increases the residence time of the gas phase in the liquid phase by combining a disc-shaped conduit and a circulation pipeline, so that the decarbonization reaction is more sufficient and complete, and the removal effect of carbon dioxide is further improved.

[0014] Preferably, as a further implementable scheme, flue gas ducts are provided at the top and bottom of the second-stage enhanced reaction tower, and a supersaturated rich liquid feed port and a supersaturated rich liquid discharge port are respectively provided on both sides of the second-stage enhanced reaction tower, and the supersaturated rich liquid feed port and the discharge port are connected; a second enhanced unit is provided at the bottom of the second-stage enhanced reaction tower, and the second enhanced unit is connected to the supersaturated rich liquid feed port.

[0015] In the present invention, a second-stage enhanced reaction tower is provided to achieve preliminary gas-liquid separation, and a second enhanced unit is provided at the bottom of the second-stage enhanced reaction tower so that the introduced saturated rich liquid can further absorb carbon dioxide in the flue gas. This is because the setting of the second enhanced unit can well increase the load in the saturated rich liquid, and accompanied by flue gas with a high carbon dioxide concentration, the saturated rich liquid can break through the bottleneck and absorb carbon dioxide in the flue gas again, thereby improving its absorption effect on carbon dioxide. In the second-stage enhanced reaction tower, the present invention introduces saturated rich liquid and high-concentration flue gas from the bottom of the second-stage enhanced reaction tower, and forms a stable gas-liquid mixture after being processed by the second enhanced unit. At this time, the gas-liquid mixture moves from bottom to top in the second-stage enhanced reaction tower. As the gas-liquid mixture rises, the flue gas after decarbonization can be discharged through the flue gas duct at the top of the second-stage enhanced reaction tower, thereby achieving a preliminary gas-liquid separation effect.

[0016] Preferably, as a further implementable scheme, it also includes an absorption tower, which is connected to the first-stage enhanced reaction tower through the rich liquid feed port, wherein a flow control valve is arranged between the absorption tower and the rich liquid feed port for controlling the flow rate of the rich liquid when flowing into the enhanced reaction tower.

[0017] Preferably, as a further feasible solution, a flue gas outlet and an absorbent feed port are provided at the top of the absorption tower, and a flue gas feed pipeline is also provided at the bottom of the absorption tower for introducing decarbonized flue gas.

[0018] Preferably, as a further implementable scheme, the absorbent feed port is connected to the absorbent liquid storage tank, and the absorbent liquid storage tank is connected to the absorption tower through the absorbent feed port; a flow control valve is also provided between the absorbent storage tank and the absorbent feed port for controlling the flow rate of the absorbent when flowing into the absorption tower.

[0019] In the present invention, the carbon dioxide in the flue gas is primarily removed by an absorption tower, wherein the absorbent is stored in an absorbent liquid storage tank connected thereto. When the flue gas is removed, the absorbent flows out of the absorbent liquid storage tank, and then the flow rate is controlled by a flow control valve from the absorbent feed port at the top of the absorption tower to ensure the full progress of the reaction. After entering the absorption tower, the absorbent will react with the flue gas that needs to be decarbonized entering the flue gas pipeline to obtain a rich liquid, and the flue gas after the preliminary decarbonization will be discharged from the flue gas outlet at the top of the absorption tower, and the rich liquid will flow into the first-stage enhanced reaction tower through the rich liquid arranged at the top of the first-stage enhanced reaction tower through the flow control valve to control its flow rate. Thereby, the rich liquid can better remove carbon dioxide from the flue gas. After entering the first-stage enhanced reaction tower through the feed port, it is mixed with the flue gas entering from the flue gas duct set at the top of the first-stage enhanced reaction tower, and then it is processed by the first enhanced unit to form a stable gas-liquid mixture for further decarbonization reaction. After the reaction is complete, saturated rich liquid is obtained. Subsequently, the saturated rich liquid will flow into the second-stage enhanced reaction tower through the discharge port set on the side of the first-stage enhanced reaction tower, and mix with the flue gas entering from the flue gas duct set at the bottom of the second-stage enhanced reaction tower. After being processed by the second-stage enhanced unit, a stable gas-liquid mixture is obtained, which further improves the removal of carbon dioxide in the flue gas and obtains supersaturated rich liquid.

[0020] Preferably, as a further implementable scheme, it also includes a heat exchanger, a gas-liquid separation tank and a regeneration tower connected in sequence, and the gas-liquid separation tank is connected to the second-stage enhanced reaction tower; interstage heating units and heat exchangers are respectively arranged on both sides of the regeneration tower, and a regeneration gas cooler and a gas-liquid separation tank connected in sequence are also arranged on the top of the regeneration tower, and a reboiler is connected to the bottom of the regeneration tower.

[0021] After decarbonization is completed, the final gas-liquid emulsion will flow out through the supersaturated rich liquid discharge port set on the side of the second-stage enhanced reaction tower, and flow into the gas-liquid separation tank connected to it for gas-liquid separation. Then the gas will be discharged through the top of the gas-liquid separation tank, and the separated liquid will flow into the heat exchanger for lean and rich liquid heat exchange. When the lean liquid is heated to 40°C through the heat exchanger, it will be transported to the absorbent storage tank for circulation through the circulation system, and the rich liquid will be passed into the regeneration tower for regeneration. The regeneration tower heats the introduced rich liquid through the regeneration tower heating unit and reboiler arranged on the outside, so that a large amount of CO2 in the reaction rich liquid is released and then transported to the regeneration gas cooler through the top of the regeneration tower for cooling, and then gas-liquid separation is achieved through the gas-liquid separation tank to obtain high-purity CO2.

[0022] The present invention also provides a decarbonization method performed by the enhanced carbon dioxide capture system, comprising the following steps: The flue gas and absorbent are mixed, broken into microbubbles and then subjected to decarbonization reaction. After gas-liquid separation, high-purity CO2 gas is obtained.

[0023] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention provides an enhanced carbon dioxide capture system, which can efficiently capture CO2 in flue gas while greatly reducing regeneration energy consumption by combining a multi-stage enhanced reaction tower and a circulation pipeline, and can also well improve the CO2 absorption rate.

[0024] (2) A decarbonization method provided by the present invention, which uses the enhanced carbon dioxide capture system provided by the present invention to efficiently capture carbon dioxide in flue gas using an absorbent, thereby greatly improving the carbon dioxide capture efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings: Figure 1 A structural diagram of an enhanced carbon dioxide capture system provided by the present invention; Figure 2 This is a schematic flow chart of the flue gas CO2 absorption method provided by the present invention.

[0026] In the accompanying drawings, the components represented by the reference numerals are listed as follows: 1. First stage enhanced reaction tower; 2. Second stage enhanced reaction tower; 3. First enhanced unit; 4. Second enhanced unit; 5. Flue gas duct; 6. Rich liquid feed port; 7. Flow control valve 1; 8. Circulation pump; 9. Circulation feed port; 10. Flow control valve 2; 11. Discharge port; 12. Flue gas duct; 13. Supersaturated rich liquid discharge port; 14. Gas-liquid separation tank 1; 15. Heat exchanger; 16. Flow control valve 3; 17. Absorption tower; 18. Absorbent storage tank; 19. Regeneration tower; 20. Interstage heating unit; 21. Gas-liquid separation tank 2; 22. Regeneration gas cooler; 23. Reboiler. DETAILED DESCRIPTION

[0027] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be understood by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0028] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", 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 limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0029] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] In order to more clearly explain the technical solution of the present invention, it is described in the form of specific embodiments below.

[0031] Example 1 See also Figure 1 As shown, the present invention is an enhanced carbon dioxide capture system, which includes 1. a first-stage enhanced reaction tower; 2. a second-stage enhanced reaction tower; 3. a first enhanced unit; 4. a second enhanced unit; 5. a flue gas duct; 6. a rich liquid feed port; 7. a flow control valve 1; 8. a circulating pump; 9. a circulating feed port; 10. a flow control valve 2; 11. a discharge port; 12. a flue gas duct; 13. a supersaturated rich liquid discharge port; 14. a gas-liquid separation tank 1; 15. a heat exchanger; 16. a flow control valve 3; 17. an absorption tower; 18. an absorbent storage tank; 19. a regeneration tower; 20. an interstage heating unit; 21. a gas-liquid separation tank 2; 22. a regenerated gas cooler; 23. a reboiler.

[0032] The flue gas used in this embodiment is the flue gas generated by coal-fired power plants and the chemical industry. The conditions for pre-treating the feed gas are: pressure 0.11 MPa, temperature 40°C, and the components in the flue gas are 5% H2O, 10.2% CO2, 79.8% N2, and 5% O2. The absorbent formulation in the absorbent storage tank 18 is amine-water, consisting of 30 wt % 2-(dimethylamino)ethanol (DMAE) and 70 wt % H O; See also Figure 2 The specific carbon dioxide capture process is as follows: the absorbent is introduced into the absorbent storage tank 18, and then the absorbent flows into the absorbent tower 17 from the absorbent feed port at the top of the absorbent tower 17 through the absorbent storage tank 18, and when the absorbent flows into the absorbent tower 17, the absorbent is controlled by the flow control valve 3 at a rate of 2m 3 / h flows into the absorption tower 17, and at the same time, the flue gas is introduced into the absorption tower 17 from the flue gas feed pipeline arranged at the bottom of the absorption tower 17. The preliminary decarbonized flue gas obtained after the absorbent and the flue gas undergo preliminary decarbonization reaction in the absorption tower 17 will be discharged from the flue gas outlet arranged at the top of the absorption tower 17, and the obtained rich liquid will flow out of the absorption tower 17, and flow into the first-stage enhanced reaction tower 1 through the rich liquid feed port 6 arranged at the top of the first-stage enhanced reaction tower, and a new round of flue gas will also be introduced from the flue gas pipeline arranged at the top of the first-stage enhanced reaction tower 1, and pass into the first enhanced unit 3 together with the rich liquid. After being processed by the first enhanced unit 3, the rich liquid and the flue gas can form a stable gas-liquid mixture for further decarbonization reaction, and then gradually descend from top to bottom to the bottom of the first-stage enhanced reaction tower 1 through the disc-shaped conduit arranged below the first enhanced unit 3, and then the circulating pump 8 sucks out the reaction liquid inside the first-stage enhanced reaction tower 1, and then enters the first-stage enhanced reaction tower 1 again from the circulating feed port 9 arranged at the top of the first-stage enhanced reaction tower 1; The saturated rich liquid will flow out from the discharge port 11 provided on the side of the first-stage enhanced reaction tower 2, and then flow into the second-stage enhanced reaction tower 2. At the same time, a new round of flue gas will also be introduced from the flue gas duct 12 provided at the bottom of the second-stage enhanced reaction tower 2, and will be introduced into the second enhanced unit 4 together with the saturated rich liquid. After being processed by the second enhanced unit 4, the saturated rich liquid and the flue gas form a stable gas-liquid mixture for further decarbonization reaction. Subsequently, the decarbonized flue gas will be discharged from the top of the second-stage enhanced reaction tower 2, and the supersaturated rich liquid will flow out from the supersaturated rich liquid discharge port 13 provided on the side of the second-stage enhanced reaction tower 2. Subsequently, the supersaturated rich liquid flows into the gas-liquid separation tank 14 for gas-liquid separation, wherein the supersaturated rich liquid in the gas-liquid separation tank 14 will achieve natural gas-liquid separation due to gravity, and the separated gas will be discharged from the top of the gas-liquid separation tank 14, and the separated liquid will flow into the heat exchanger 15 for heat exchange, wherein the lean liquid obtained after the heat exchange is completed will flow from the top of the heat exchanger through the top of the absorbent storage tank into the absorbent storage tank for recycling, and the rich liquid will flow from the heat exchanger 15 into the regeneration tower 19, and after passing through the regeneration tower The interstage heating unit 20 and the reboiler 23 arranged on the outside of 19 heat the liquid flowing into the regeneration tower, so that the CO2 in the liquid is released in large quantities. The released CO2 will be sent to the top of the regeneration tower and transported to the regeneration gas cooler for cooling. After cooling, it will pass through the gas-liquid separation tank 21 again to achieve gas-liquid separation. The high-purity CO2 obtained after separation will be discharged from the top of the gas-liquid separation tank 21, and the liquid will flow into the regeneration tower 19 from the bottom of the gas-liquid separation tank 21 again for circulation heating.

[0033] Comparative Example 1 The specific implementation is consistent with Example 1, except that the disc-shaped conduit is not provided.

[0034] Comparative Example 2 The specific implementation method is consistent with Example 1, except that the first strengthening unit is not used, and the disc-shaped duct is connected to the flue gas duct and the rich liquid feed port.

[0035] Comparative Example 3 The specific implementation method is consistent with Example 1, except that the circulation pipeline is not used.

[0036] Comparative Example 4 The specific implementation method is consistent with Example 1, except that the second strengthening unit is not used.

[0037] Comparative Example 5 The specific implementation is consistent with that of Example 1, except that the flow control valve 8 is not used.

[0038] Experimental Example 1 CO2 load and regeneration energy consumption measurement The supersaturated rich solution obtained after treatment according to Example 1 and Comparative Examples 1-5 was titrated to determine the final CO2 absorption load. The specific determination method is as follows: Detection steps: Take 1g of supersaturated rich liquid and add it to 30g of water for absorption. Add the diluted liquid into a closed reactor connected to a gas measuring tube. Add dilute sulfuric acid into the reactor to release the absorbed CO2 from the liquid phase, and measure the change in total gas volume in the gas measuring tube. Use the formula to determine the total CO2 load a.

[0039] The calculation formula is as follows:

[0040] Where a is the carbon dioxide load (mol / kg), mabs is the sample mass of the absorbent (kg), and are the volume changes of the gas tube and the acid burette, respectively.

[0041] The above test detection method is not only applicable to the CO2 absorption process, but also can be applied to the determination of CO2 regeneration energy consumption. The regeneration test is carried out through pilot equipment and measured using an electric meter. The measured energy consumption includes three parts: reaction heat, sensible heat for solution heating and evaporation heat for water evaporation.

[0042] Test steps: The regeneration temperature was maintained at 373.15 K, the liquid flow rate was 0 to 100 mL / min, and the gas flow rate was 0 to 30 L / min; the regeneration energy consumption was measured using an ammeter.

[0043] The final measurement results are shown in Table 1 below:

[0044] According to the above Table 1, the enhanced carbon dioxide capture system and decarbonization method provided by the present invention are provided with a multi-stage enhanced reaction tower, and an enhanced unit is provided in the tower of the multi-stage enhanced reaction tower, so as to increase the load of the reaction liquid introduced into the reaction tower, which can effectively promote the gas-liquid mass transfer process, improve the removal rate of CO2 in the flue gas, reduce the regeneration energy consumption, and realize the deflection of the reaction liquid through the external circulation pipeline, so that the reaction liquid entering from the top of the enhanced reaction tower is re-input from the bottom of the tower to the top of the tower through the setting of the circulation pipeline when reaching the bottom of the tower, thereby being able to well increase the residence time of the reaction liquid in the enhanced reaction tower, and further improve the removal rate of CO2 in the flue gas.

[0045] By comparing Example 1 with Comparative Example 1, it can be known that the arrangement of the disc-shaped conduit is necessary for the present invention, because the arrangement of the disc-shaped conduit below the first enhanced unit further increases the residence time of the reaction liquid in the first-stage enhanced reaction tower. In the process of the reaction liquid running from top to bottom, the falling speed of the reaction liquid will gradually decrease until it stops after running to the bottom of the reactor, and the gas phase in the reaction liquid will gradually rise in the liquid phase under the influence of buoyancy, and the arrangement of the disc-shaped conduit can make the gas phase in the reaction liquid stay in the liquid phase for a longer time, thereby further improving the removal of carbon dioxide in the flue gas.

[0046] By comparing Example 1 and Comparative Example 2, it can be known that, for the present invention, the provision of the first intensification unit is very necessary. This is because the present invention arranges the first intensification unit inside the first-stage intensified reaction tower, thereby breaking the flue gas into microbubbles and mixing them with rich liquid to form a stable gas-liquid mixture. The treated gas-liquid mixture, i.e., the reaction liquid, has a higher loading capacity, thereby improving the reaction liquid's ability to capture carbon dioxide in the flue gas, effectively promoting the gas-liquid mass transfer process, and improving the removal rate of CO2 in the flue gas.

[0047] By comparing Example 1 and Comparative Example 3, it can be seen that the setting of the circulation pipeline is very important for the present invention. This is because the present invention mainly combines the first-stage enhanced reaction tower and the circulation pipeline so that the reaction liquid can flow in from the top of the enhanced reaction tower. The residence time of the reaction liquid in the enhanced reaction tower is increased through the conduit, and the reaction liquid can also reach the bottom of the enhanced reaction tower from top to bottom. Subsequently, the reaction liquid reaching the bottom is introduced from the top of the reaction tower again through the circulation pipeline, thereby further increasing the residence time of the reaction liquid, making the decarbonization reaction more sufficient and thorough, and further improving the removal of carbon dioxide in the flue gas. The present invention introduces the reaction liquid from the top of the enhanced reaction tower, so that the reaction liquid can move from top to bottom in the reaction tower. As the reaction liquid descends to the bottom of the reaction tower, its speed will decrease accordingly until it stops. Since the reaction liquid moves from top to bottom, the gas phase in the reaction liquid will be affected by buoyancy and gradually rise in the liquid phase. During the rising process, the gas rate gradually decreases. Through such an arrangement, the residence time of the gas phase in the liquid phase can be increased, further improving the removal effect of carbon dioxide. Therefore, the present invention greatly increases the residence time of the gas phase in the liquid phase by combining a disc conduit and a circulation pipeline, so that the decarbonization reaction is more sufficient and complete, and the removal effect of carbon dioxide is further improved.

[0048] By comparing Example 1 and Comparative Example 4, it can be seen that the setting of the second enhanced unit can further absorb carbon dioxide in the flue gas for the present invention. This is because the setting of the second enhanced unit can well increase the load in the supersaturated rich liquid, and accompanied by the flue gas with a high carbon dioxide concentration, the supersaturated rich liquid can break through the bottleneck and absorb the carbon dioxide in the flue gas again, thereby achieving an efficient carbon dioxide absorption effect. In the second-stage enhanced reaction tower, the present invention introduces supersaturated rich liquid and high-concentration flue gas from the bottom of the second-stage enhanced reaction tower, and forms a stable gas-liquid mixture after being processed by the second enhanced unit. At this time, the gas-liquid mixture moves from bottom to top in the second-stage enhanced reaction tower. As the gas-liquid mixture rises, the flue gas after decarbonization can be discharged through the flue gas duct at the top of the second-stage enhanced reaction tower, thereby achieving a preliminary gas-liquid separation effect. By comparing Example 1 with Comparative Example 5, it can be seen that the flow control valve of the present invention is set to control the amount of rich liquid flowing into the first stage enhanced reaction tower by the absorbent to be at 2m 3 / h-8m 3 When the flow rate is 0.0447 W / h, when the reaction liquid flows into the enhanced reaction tower, the removal of carbon dioxide in the flue gas can achieve excellent results. This is because in order to achieve enhanced absorption of carbon dioxide, the present invention requires nearly saturated rich liquid and flue gas to flow into the enhanced reaction tower at a certain flow rate. After being processed by the enhanced unit, the flue gas is broken into microbubbles, so that the flue gas broken into microbubbles and the rich liquid form a stable gas-liquid mixture. In this way, the load of the reaction liquid is greatly increased, and the removal of CO2 is improved. If the flow rate is too low, the reaction system in the enhanced reaction tower will be saturated prematurely, affecting the capture of carbon dioxide in the flue gas; if the flow rate is too fast, the load in the reaction liquid will be too low, so that the reaction liquid cannot absorb carbon dioxide in the flue gas, thereby affecting the removal effect of carbon dioxide.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An enhanced carbon dioxide capture system, characterized in that: It comprises a multi-stage enhanced reaction tower, on which a flue gas duct, a rich liquid feed port and a discharge port are arranged; an enhanced unit is arranged inside the multi-stage enhanced reaction tower, and a circulation pipeline is also arranged outside the multi-stage enhanced reaction tower, on which a circulation pump and a flow control valve are arranged in sequence.

2. The enhanced carbon dioxide capture system according to claim 1, characterized in that: The multi-stage enhanced reaction tower is a two-stage enhanced reaction tower, wherein the two-stage enhanced reaction tower comprises a first-stage enhanced reaction tower and a second-stage enhanced reaction tower.

3. The enhanced carbon dioxide capture system according to claim 2, characterized in that: A first strengthening unit is arranged at the top of the first-stage strengthening reaction tower, and a disc-shaped duct is arranged below the first strengthening unit; the rich liquid feed port and the flue gas duct are arranged in sequence at the top of the first-stage strengthening reaction tower, and a discharge port and a circulation feed port are respectively arranged on both sides of the first-stage strengthening reaction tower.

4. The enhanced carbon dioxide capture system according to claim 3, characterized in that: The circulation pipeline is arranged outside the first-stage enhanced reaction tower, and the circulation pump is connected to the circulation feed inlet.

5. The enhanced carbon dioxide capture system according to claim 2, characterized in that: The top and bottom of the second-stage enhanced reaction tower are both provided with flue gas ducts, and both sides of the second-stage enhanced reaction tower are respectively provided with a supersaturated rich liquid feed inlet and a supersaturated rich liquid discharge port, and the supersaturated rich liquid feed inlet is connected to the discharge port; a second enhanced unit is provided at the bottom of the second-stage enhanced reaction tower, and the second enhanced unit is connected to the supersaturated rich liquid feed inlet.

6. The enhanced carbon dioxide capture system according to claim 2, characterized in that: It also includes an absorption tower, which is connected to the first-stage enhanced reaction tower through the rich liquid feed port, wherein a flow control valve is arranged between the absorption tower and the rich liquid feed port for controlling the flow rate of the rich liquid when flowing into the enhanced reaction tower.

7. The enhanced carbon dioxide capture system according to claim 6, characterized in that The top of the absorption tower is provided with a flue gas outlet and an absorbent feed port, and the bottom of the absorption tower is also provided with a flue gas feed pipeline for introducing decarbonized flue gas.

8. The enhanced carbon dioxide capture system according to claim 7, characterized in that The absorbent feed port is connected to the absorbent liquid storage tank, and the absorbent liquid storage tank is connected to the absorption tower through the absorbent feed port; a flow control valve is also provided between the absorbent storage tank and the absorbent feed port for controlling the flow rate of the absorbent when flowing into the absorption tower.

9. The enhanced carbon dioxide capture system according to claim 8, characterized in that It also includes a gas-liquid separation tank, a heat exchanger and a regeneration tower connected in sequence, wherein the gas-liquid separation tank is connected to the second-stage enhanced reaction tower; an interstage heating unit is arranged on the outside of the regeneration tower, a regeneration gas cooler and a gas-liquid separation tank connected in sequence are also arranged on the top of the regeneration tower, and a reboiler is connected to the bottom of the regeneration tower.

10. A decarbonization method performed by the enhanced carbon dioxide capture system according to any one of claims 1 to 9, characterized in that: The following steps are involved: The flue gas and absorbent are mixed, broken into microbubbles and then subjected to decarbonization reaction. After gas-liquid separation, high-purity CO2 gas is obtained.

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