Flue gas purification and CO2 capture and coupling system and carbon capture method
The flue gas purification and CO2 capture system addresses high energy consumption and cost issues by using waste heat from flue gas to generate superheated poor liquid for CO2 desorption, achieving significant cost reductions and operational improvements.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- HUANENG CLEAN ENERGY RES INST
- Filing Date
- 2025-12-23
- Publication Date
- 2026-07-07
AI Technical Summary
The high energy consumption and cost associated with carbon capture in CCUS technology, particularly due to steam consumption for CO2 regeneration, and the need for significant modifications to existing equipment systems, hinder its widespread adoption.
A flue gas purification and CO2 capture system that utilizes a portion of the poor liquid discharged from the regeneration tower to exchange heat with high-temperature flue gas, forming superheated poor liquid to provide steam and heat for CO2 desorption, reducing the reliance on external superheated steam and minimizing equipment modifications.
This system effectively reduces energy consumption and capture costs by 40-50% while improving operational safety and stability, avoiding issues like pipe leakage and equipment vibration, and reducing the impact on power generation units.
Smart Images
Figure 2026113437000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of carbon capture, utilization and storage (CCUS) technology, and specifically to a flue gas purification and CO2 capture combined system and method.
Background Art
[0002] Carbon capture, utilization and storage (CCUS) is an important means for the large-scale low-carbon utilization of fossil energy, and plays an important driving and guarantee role in the country's energy security and the construction of an energy power country. High energy consumption and high cost are the main obstacles to the large-scale popularization of CCUS technology. However, the carbon capture cost accounts for 75% of the total chain cost. Reducing the carbon capture cost is an international issue that must be urgently solved for the development of CCUS technology. The capture cost mainly lies in the steam consumption during regeneration. That is, the heat required for CO2 regeneration is usually supplied from the superheated steam extracted from the power generation unit of the power plant. Since a large amount of steam is consumed, the carbon capture cost is relatively high, and the proportion of the steam cost in the total capture cost reaches about 50%. In addition, when steam is extracted, the power generation efficiency of the power plant decreases, the auxiliary load loss of the power plant increases, and the capture cost further rises. Moreover, accessing the CO2 capture system requires significant modification of the existing equipment system, which affects the flue gas purification treatment. In related technologies, it has also been proposed to use the waste heat of flue gas to supply heat to the carbon capture system instead of extracting superheated steam. However, there are many problems such as insufficient heat utilization in the system, unreasonable temperature matching, and relatively high energy consumption, which affect the actual use, so there is a need for improvement.
Summary of the Invention
Problems to be Solved by the Invention
[0003] The present invention intends to solve at least to some extent one of the technical problems in the related art.
Means for Solving the Problems
[0004] Therefore, the present invention proposes a flue gas purification and CO2 capture and coupling system. This flue gas purification and CO2 capture and coupling system has the advantage of reducing the energy consumption required for capture.
[0005] The flue gas purification and CO2 capture / combination system includes a flue gas generator, a flue gas purification device, and a CO2 capture device.
[0006] The flue gas discharged from the flue gas generator is purified by the flue gas purification device and then enters the CO2 collection device, where it undergoes CO2 collection and decarbonization before finally being discharged to the outside, simultaneously completing the separation and storage of CO2. Here, the CO2 collection device includes an absorption tower and a regeneration tower. The rich liquid CO2 collected in the absorption tower flows into the regeneration tower and is desorbed into regenerated gas and poor liquid by heat. The regenerated gas and poor liquid are discharged from the regeneration tower, respectively. A portion of the poor liquid discharged from the regeneration tower exchanges heat with the flue gas discharged from the flue gas generator that did not enter the CO2 collection device, becoming superheated poor liquid. The superheated poor liquid returns to the regeneration tower, providing steam and heat for the desorption. The superheated poor liquid is characterized in that it is CO2 poor liquid that maintains a state of awaiting boiling under a preset pressure.
[0007] In some embodiments, the flue gas generator includes a boiler and an air preheater, and the flue gas discharged from the boiler passes through the air preheater and then exchanges heat with a portion of the poor liquid.
[0008] In some embodiments, the CO2 collection equipment includes a reboiler, and the flue gas generated from the flue gas generator passes through the reboiler to exchange heat with a portion of the poor liquid, and the portion of the poor liquid after heat exchange returns to the regeneration tower to provide heat for the regeneration reaction.
[0009] In some embodiments, the CO2 capture device further includes a rich-liquid heat exchanger, where the rich liquid discharged from the absorption tower passes through the rich-liquid heat exchanger and enters the regeneration tower, and the rest of the poor liquid discharged from the regeneration tower enters the rich-liquid heat exchanger, exchanges heat with the rich liquid flowing through the rich-liquid heat exchanger, and then enters the absorption tower.
[0010] In some embodiments, the flue gas purification equipment includes a denitrification tower and a desulfurization tower, and the flue gas discharged from the boiler passes through the denitrification tower, the air preheater and the desulfurization tower to enter the absorption tower, where it undergoes CO2 capture and decarbonization before becoming decarbonized flue gas, which is then discharged to the outside from inside the absorption tower.
[0011] In some embodiments, the CO2 collection device further includes a pressurizing pump, which is located between the regeneration tower and the reboiler, and is used to pressurize a portion of the poor liquid to raise its boiling point.
[0012] In some embodiments, the CO2 collection device further includes a pressure reducing valve, which is located between the reboiler and the regeneration tower and adjacent to the regeneration tower, and is used to reduce the pressure of the superheated poor liquid after it has passed through the reboiler and exchanged heat with the flue gas, thereby lowering the boiling point of the superheated poor liquid, which then returns to the regeneration tower and releases steam.
[0013] In some embodiments, the regeneration tower has a poor liquid inlet, where the superheated poor liquid after depressurization returns to the regeneration tower through the poor liquid inlet, and the poor liquid inlet is lower than the filler in the regeneration tower and higher than the liquid level of the poor liquid tank at the bottom of the regeneration tower.
[0014] In some embodiments, the pressurizing pump pressurizes a portion of the poor liquid discharged from the regeneration tower to 3-7 atmospheres.
[0015] In some embodiments, the pressure reducing valve reduces the pressure of the superheated poor liquid discharged from the reboiler to 1.2-2.0 atmospheres.
[0016] In some embodiments, the gas phase accounts for 2%-15% of the total mass of the poor liquid returned to the regeneration column after depressurization.
[0017] In some embodiments, the mass percentage of the poor liquid portion relative to the total poor liquid discharged from the regeneration tower is 20%-60%.
[0018] In some embodiments, the CO2 collection device further includes a rich liquid preheater, and the rich liquid generated from the absorption tower passes sequentially through the rich liquid preheater and the poor liquid heat exchanger before entering the regeneration tower, and the regenerated gas generated from the regeneration tower enters the rich liquid preheater and exchanges heat with the rich liquid that has passed through the rich liquid preheater.
[0019] In some embodiments, the CO2 capture device further includes a flue gas reheater, and the remaining portion of the poor liquid discharged from the regeneration tower passes through the rich-poor-rich liquid heat exchanger and the flue gas reheater in order to enter the absorption tower, and the decarbonized flue gas discharged from the absorption tower enters the flue gas reheater, exchanges heat with the poor liquid that has passed through the flue gas reheater, and is then discharged to the outside.
[0020] In some embodiments, the CO2 collection device further includes a flow control valve used to control the ratio of flue gas discharged from the desulfurization tower to enter the flue gas reheater and to enter the absorption tower.
[0021] In some embodiments, a flow meter, often paired with a flow control valve, is installed to monitor the flow rate of flue gas entering the CO2 collection device.
[0022] In some embodiments, the flue gas purification equipment further includes two flow control valves and a blower, the blower being installed between the desulfurization flue gas outlet of the desulfurization tower and the prewash tower, one of the control valves being installed between the desulfurization flue gas outlet of the desulfurization tower and the intake of the flue gas reheater to control the amount of desulfurization flue gas discharged from the desulfurization tower entering the flue gas reheater, the other control valve being installed between the desulfurization flue gas outlet of the desulfurization tower and the blower to control the amount of flue gas entering the prewash tower from the desulfurization tower, and the two control valves being controlled in conjunction with each other.
[0023] In some embodiments, the flue gas purification equipment further includes a pre-wash tower, a dust collector, and a chimney, and the CO2 collection equipment further includes a CO2 compressor, wherein the dust collector is located between the reboiler and the desulfurization tower and is used to remove dust from the flue gas discharged from the reboiler, and the CO2 compressor is connected to the rich liquid preheater and compresses the regenerated gas after heat exchange with the rich liquid in the rich liquid preheater.
[0024] The flue gas purification and CO2 capture and coupling method of the present invention is as follows: Flue gas discharged from flue gas generators is purified by flue gas purification equipment before entering CO2 capture equipment. After CO2 capture and decarbonization, it is finally discharged to the outside, simultaneously completing CO2 storage. The CO2 capture equipment includes an absorption tower and a regeneration tower. The rich liquid CO2 captured in the absorption tower flows into the regeneration tower, where it is desorbed into regenerated gas and poor liquid by heat. The regenerated gas and poor liquid are then discharged from the regeneration tower, respectively. A portion of the poor liquid discharged from the regeneration tower exchanges heat with the flue gas discharged from the flue gas generator before it enters the CO2 capture equipment to become superheated poor liquid, and this superheated poor liquid returns to the regeneration tower, providing steam and heat for the desorption process.
[0025] In some embodiments, the combined method for flue gas purification and CO2 capture according to the embodiments of the present invention further includes pressurizing a part of the lean liquid discharged from the regeneration tower to raise its boiling point, where, after pressurization, a part of the lean liquid exchanges heat with the flue gas discharged from the flue gas generating equipment and not entering the CO2 capture equipment.
[0026] In some embodiments, the combined method for flue gas purification and CO2 capture according to the embodiments of the present invention further includes depressurizing the superheated lean liquid to lower its boiling point, where the superheated lean liquid after depressurization returns to the regeneration tower.
[0027] In some embodiments, the superheated lean liquid after depressurization returns to below the filler in the regeneration tower.
[0028] In some embodiments, the rich liquid discharged from the absorption tower is sequentially heat-exchanged with the regeneration gas discharged from the regeneration tower and the other part of the lean liquid discharged from the regeneration tower, and then flows into the regeneration tower.
[0029] In some embodiments, the combined method for flue gas purification and CO2 capture according to the embodiments of the present invention passes the flue gas discharged from the flue gas generating equipment through denitrification, air preheating, heat exchange with a part of the lean liquid discharged from the regeneration tower, dust removal, and desulfurization in sequence. A part of the desulfurized flue gas and the other part of the lean liquid discharged from the regeneration tower and heat-exchanged with the rich liquid are both heat-exchanged with the decarbonated flue gas discharged from the absorption tower. The other part of the lean liquid after heat-exchanging with the decarbonated flue gas flows into the absorption tower. A part of the flue gas after desulfurization and the decarbonated flue gas after heat-exchanging with the other part of the lean liquid are discharged to the outside, and another part of the desulfurized flue gas enters the absorption tower.
[0030] In some embodiments, the ratio of a part of the desulfurized flue gas that exchanges heat with the decarbonated flue gas to another part of the desulfurized flue gas entering the absorption tower is controlled.
[0031] In some embodiments, the flue gas can originate from multiple locations where high-temperature flue gas is generated, such as power plant boilers, cement plant exhaust gases, and steel plant exhaust gases. [Effects of the Invention]
[0032] The present invention uses a portion of the poor liquid discharged from the regeneration tower to exchange heat with high-temperature flue gas that has not entered the CO2 capture equipment after leaving the flue gas generator, forming superheated poor liquid which returns to the regeneration tower to provide regeneration reaction vapor and heat to CO2. A portion of the superheated poor liquid vaporizes and returns to the regeneration tower, promoting the desorption of CO2 within the regeneration tower. In other words, the heat required for CO2 regeneration is provided from the high-temperature flue gas, and the poor liquid is heated by the flue gas to form vapor which participates in the regeneration process. By replacing some, or even all, of the conventional vapor from outside the system, the consumption of expensive superheated vapor can be avoided, the energy consumption of the system can be effectively reduced, and the capture cost per ton of CO2 can be reduced by 40%-50%.
[0033] At the same time, using the system of the present invention is advantageous when adding additional equipment when modifying existing related equipment, and the system modification cost is significantly reduced by simply increasing the amount of piping.
[0034] Furthermore, this invention utilizes pressurized poor liquid to exchange heat with flue gas to form superheated poor liquid, and prevents the superheated poor liquid from vaporizing in large quantities within the reboiler under pressurized conditions, thus avoiding equipment vibration or gas etching phenomena caused by gas collision with the heat exchange tubes or heat exchange walls of the reboiler. As a result, this invention has the advantage of improving equipment service life, operational stability, and safety.
[0035] Therefore, the flue gas purification and CO2 capture and coupling system of the embodiment of the present invention has the advantage of improving operational safety and reducing capture costs. [Brief explanation of the drawing]
[0036] [Figure 1]This is a schematic diagram of a flue gas purification and CO2 capture and coupling system according to an embodiment of the present invention. [Figure 2] This is a schematic diagram of a flue gas purification and CO2 capture and coupling system according to another embodiment of the present invention. [Modes for carrying out the invention]
[0037] The embodiments of the present invention will be described in detail below, and examples of these embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are illustrative and intended to interpret the present invention, and should not be understood as limiting the present invention.
[0038] The flue gas purification and CO2 capture / combination system of an embodiment of the present invention will be described below with reference to the attached drawings, where the flue gas originates from a power plant boiler 1. The combination system is, in particular, the combination of a flue gas treatment system and a CO2 capture system. Here, the flue gas discharged from boiler 1 is desulfurized and denitrified, and then CO2 is captured using a CO2 absorbent solution. After carbon capture, the flue gas becomes decarbonized flue gas and is discharged to the outside. Commonly used CO2 absorbent solutions include, but are not limited to, organic amine solutions, alkaline amino acid salt solutions, alkaline inorganic salt solutions, and ionic liquid and metal-organic framework solutions.
[0039] As shown in Figure 1, Example 1, the flue gas purification and CO2 capture and coupling system of the present invention, includes a boiler 1, a denitrification tower 2, an air preheater 3, a reboiler 4, a dust collector 17, a desulfurization tower 16, a pre-wash tower 14, an absorption tower 13, a rich liquid preheater 10, a poor liquid heat exchanger 9, a regeneration tower 6, a pressure pump 7, a pressure reducing valve 5, a flue gas reheater 18, a chimney 19, and a CO2 compressor 11.
[0040] The flue gas discharged from boiler 1 enters denitrification tower 2 and is denitrified. After denitrification, the flue gas passes sequentially through air preheater 3 and reboiler 4 before entering dust collector 17 for dust removal. After dust removal, the flue gas is desulfurized in desulfurization tower 16. After desulfurization, the flue gas is sent from blower 15 to pre-wash tower 14 for pre-washing. After pre-washing, the flue gas enters absorption tower 13, where CO2 is captured by an absorbent solution (poor liquid) to become decarbonized flue gas. The absorbent solution becomes rich liquid after capturing CO2 in absorption tower 13. The decarbonized flue gas is discharged from the top of absorption tower 13, enters flue gas reheater 18, is reheated in flue gas reheater 18, and then discharged into chimney 19. The rich liquid in the absorption tower 13 is transported from the bottom of the absorption tower 13 by the rich liquid pump 12, and flows sequentially through the rich liquid preheater 10 and the poor liquid heat exchanger 9 before entering the regeneration tower 6. In the regeneration tower 6, the rich liquid is superheated and desorbed to regenerate it and obtain regenerated gas. The rich liquid is desorbed and regenerated to become poor liquid, and the regenerated gas enters the CO2 compressor 11, where it is compressed and stored. The poor liquid is then returned to the absorption tower 13 for reuse.
[0041] It should be noted that conventional CO2 capture processes have relatively high renewable energy consumption and operating costs. The rich liquid with CO2 supported on the absorbent is all sent to the regeneration tower 6 for heating and regeneration. However, the proportion of water in the absorbent is relatively high (generally over 70%), and the heating and volatilization of water during the high-temperature CO2 desorption process consumes a huge amount of energy (over 50%). Therefore, changing the water environment in the regeneration process and reducing the degree of water participation in the regeneration process is expected to maximize the use of steam heat and reduce renewable energy consumption. In general technology, heat necessary for regeneration is usually introduced from an external source, for example, by using steam generated from a power plant's steam turbine. This process requires matching equipment such as piping, while consuming superheated steam and increasing energy consumption. At the same time, the flue gas discharged from boiler 1 has a relatively high temperature, remaining at 350-400°C even after passing through denitrification tower 2. After passing through the air preheater, the temperature can be maintained at 100-180°C and is applied to provide the heat necessary for desorption to the rich liquid. Therefore, rationally utilizing the heat in this section to obtain the heat necessary for the absorbent regeneration process is an important means of reducing the overall energy consumption of the system.
[0042] In this embodiment, the overall energy consumption of the coupled system is effectively reduced by changing the steam environment during the regeneration process by drawing out a portion of the poor liquid discharged from the regeneration tower 6 and exchanging heat with the boiler 1 flue gas to form a superheated liquid. Here, the superheated poor liquid is a superheated CO2 poor liquid that is maintained in a state awaiting boiling under a predetermined pressure, and the predetermined pressure is generally superatmospheric pressure. Selectively, the flue gas can be derived from several locations where high-temperature flue gas is generated, such as power plant boilers, cement plant exhaust gases, and steel plant exhaust gases.
[0043] Specifically, as shown in Figure 1, a portion of the poor liquid discharged from the regeneration tower 6 enters one end of the reboiler 4, and the other orthogonal end of the reboiler 4 is connected to the boiler 1 by piping. As a result, a portion of this poor liquid exchanges heat with the flue gas that has passed through the reboiler 4. After heat exchange, the temperature of a portion of the poor liquid rises, forming a superheated poor liquid of mixed liquid steam. This superheated poor liquid returns to the regeneration tower 6 along the piping, and the steam in the superheated poor liquid is released, providing the heat necessary for the regeneration process and enabling efficient utilization of the waste heat of the flue gas. It should be noted that in this embodiment, the poor liquid is heated by the flue gas to form a superheated poor liquid, and the steam in the superheated poor liquid participates in the regeneration process, thereby avoiding the consumption of expensive superheated steam by replacing some or all of the conventional steam derived from the steam turbine. For example, conventional CO2 rich-liquid desorption requires steam extracted from the power generation unit to heat and desorb the rich liquid in the regeneration tower. Thus, the present invention reduces the impact on the power generation unit and lowers the energy consumption and cost of carbon capture.
[0044] The remaining portion of the poor liquid discharged from the regeneration tower 6 enters the poor-to-rich liquid heat exchanger 9, facilitating heat exchange with the rich liquid flowing through the poor-to-rich liquid heat exchanger 9. The remaining portion of the poor liquid after heat exchange enters the absorption tower 13, where it is used to capture CO2 in the absorption flue gas.
[0045] On the other hand, in the embodiment of the present invention, the flue gas generated from the power plant boiler 1 first passes through the denitrification tower 2 to be denitrified, and the temperature of the high-temperature flue gas when it exits the boiler 1 can be reduced from about 800-1000°C to about 350-400°C, and is further cooled to about 100-180°C by an air preheater. At this point, the flue gas still has a relatively high temperature and relatively high available energy (exergy), and may be used to supplement the regeneration process with the highest energy consumption, or it may be used to supplement the absorbent regeneration process with the highest energy consumption. Therefore, a reboiler 4 with a thermal energy collection function is added, and a portion of the poor liquid generated in the regeneration tower 6 is extracted and enters the reboiler 4, where it exchanges heat with the high-temperature flue gas after denitrification to form superheated poor liquid. This superheated poor liquid enters the regeneration tower 6 and becomes a gas-liquid two-phase state. Here, the gas flows upward in the regeneration tower 6, conducting the accompanying heat to the filler layer to promote the desorption reaction of CO2 in the rich liquid, enabling effective utilization of the residual heat of the flue gas. The liquid phase flows to the bottom of the tower and is recycled. The temperature of the flue gas flowing through the reboiler 4 is approximately between 100°C and 180°C, and the temperature of the poor liquid discharged from the regeneration tower 6 is approximately between 80°C and 140°C. It is necessary to maintain a heat exchange temperature difference of more than 5°C between the two, and the heat exchange between the two within the reboiler 4 has the advantage of reducing relative heat loss.
[0046] On the other hand, it should be noted that in this embodiment, the transfer of residual heat from the flue gas utilizes a portion of the poor liquid drawn from the regeneration tower 6. By selecting this portion of the poor liquid, the temperature of this portion of the poor liquid is relatively appropriate, and because the poor liquid itself is recovered and reused, the difficulty of modifying existing equipment with additional equipment required for heat exchange is reduced, thereby lowering modification costs. It should also be noted that in this field, related technologies have proposed a method in which a portion of the flue gas directly discharged from the boiler 1 heats the rich liquid (45-65°C) discharged from the regeneration tower 6 in the reboiler 4, and after heat exchange, the rich liquid is circulated and returned to the regeneration tower 6. However, the inventors of the present invention have found through research that, because the flue gas temperature from boiler 1 is relatively high (approximately 800-1000°C), the above method results in severe thermal decomposition of the absorbent in the rich liquid, and the rich liquid is rich in absorbed CO2. As a result, the piping becomes filled with desorbed CO2 gas after heat exchange with the high-temperature flue gas under normal pressure. These gases collide with the piping, creating noise and easily causing leaks. Furthermore, scale easily forms in the piping, leading to blockages, affecting operation, and potentially causing serious safety accidents. In contrast, the embodiment of the present invention uses a relatively low temperature and utilizes heat exchange between the poor liquid and flue gas to provide at least some of the heat necessary for absorbent regeneration using the residual heat of the flue gas. Since the poor liquid is less likely to desorb CO2 in the piping, the amount of CO2 gas in the piping is small.
[0047] Simultaneously, a poor-liquid pump 8 capable of pressurizing is provided in the piping at the bottom of the regeneration tower 6, and a portion of this drawn-out poor-liquid is first pressurized to 3-7 atmospheres via this poor-liquid pump 8. Preferably, the poor-liquid pump 8 pressurizes the poor-liquid to 3-6 atmospheres, which lowers the boiling point of the poor-liquid after it has been heated in the reboiler 4 and then heated by heat exchange after pressurization, making it less likely to vaporize. This reduces the vapor content in the poor-liquid in this section of the piping. The poor-liquid fluid under relatively high pressure absorbs heat from the flue gas to form superheated poor-liquid, and this superheated poor-liquid is accompanied by heat absorbed from the flue gas, and its temperature reaches the desorption temperature required for the regeneration process, which can help ensure the smooth progress of the regeneration process. Simultaneously, before the heat-exchanged poor liquid re-enters the regeneration tower 6, a pressure reducing control valve is added to further reduce the pressure of the heated, high-pressure superheated poor liquid to 1-2 atmospheres, lowering its boiling point. As a result of the reduced pressure, some of the liquid in the superheated poor liquid volatilizes and turns into hot vapor, which returns to the regeneration tower 6 and participates in the regeneration process. Furthermore, some of the poor liquid returns to the regeneration tower 6 after the pressure reduction, and the mass percentage of the gas phase in the total returned poor liquid is 2%-15%. If it exceeds 15%, problems such as gas collisions with the pipes occur due to the excess gas filling the piping. If it is less than 2%, the accompanying heat is reduced and it returns to the regeneration tower 6, reducing the waste heat utilization rate.
[0048] In another embodiment, the pressure pump 7 is installed adjacent to the poor liquid outlet of the regeneration tower 6, and the pressure reducing valve 5 is installed adjacent to the poor liquid inlet of the regeneration tower 6. For example, the pressure reducing valve 5 can be attached to the poor liquid inlet of the regeneration tower 6. The poor liquid inlet of the regeneration tower 6 is located below the filler inside the regeneration tower 6, for example, adjacent to the bottom surface of the filler. More preferably, the poor liquid inlet is higher than the poor liquid level at the bottom of the regeneration tower 6, and the superheated poor liquid that returns into the regeneration tower 6 first comes into contact with the poor liquid below the regeneration tower 6 for heat exchange. This avoids the problem of low desorption efficiency due to the inability to fully utilize the heat attached to the poor liquid in this portion for desorption of the rich liquid, and further improves the desorption efficiency of the rich liquid.
[0049] In another embodiment, the mass percentage of this poor liquid relative to the total poor liquid discharged from the regeneration tower 6 is 20%-60%.
[0050] In another embodiment, the regenerated gas is discharged from the top of the regeneration tower 6, at which point the temperature of the regenerated gas is 60°C or higher, meaning it still has a certain amount of heat. This gas is then guided into the rich liquid preheater 10, where it exchanges heat with the rich liquid from the absorption tower 13. In other words, the regenerated gas is used to heat the rich liquid flowing from the absorption tower 13 to the regeneration tower 6, thereby recovering the heat associated with the regenerated gas and using it to regenerate the adsorbent. After the heat exchange with the rich liquid, the regenerated gas is finally compressed and stored in the CO2 compressor 11.
[0051] In another embodiment, the flue gas enters the reboiler 4 after denitrification and before dust removal, meaning that the residual heat of the flue gas is utilized after denitrification and before dust removal. Although processing the high-temperature flue gas by the dust collector 17 is relatively difficult and the flue gas needs to be cooled to 90°C, the flue gas temperature after denitrification can still reach 180°C. Therefore, it is relatively more rational to install the reboiler 4 between the denitrification tower 2 and the dust collector 17 to utilize the residual heat of the flue gas.
[0052] In another embodiment, the decarbonized flue gas discharged from the absorption tower 13 is heated in the flue gas reheater 18 before entering and being discharged into the chimney 19, thereby increasing the flue gas temperature in the chimney 19 (generally raising the flue gas temperature to 80°C or higher) and reducing the "white mist" phenomenon from the chimney 19.
[0053] In the flue gas purification and CO2 capture / coupling system of the embodiment of the present invention, the efficiency of heat circulation utilization within the system, such as the waste heat of the flue gas and the heat associated with regenerated gas and the lean liquid, is improved, steam consumption is significantly reduced, and CO2 capture costs can be lowered by 40%-50%. At the same time, by adopting this system, the impact on the power generation unit due to steam extraction is reduced, and additional equipment such as steam desaturators and pressure reducers is reduced. Furthermore, by adopting the heat exchange mode of this system, problems such as pipe leakage, collision vibration, and gas etching, which are prone to occur in related technologies due to gas collision with piping, are overcome, improving the operational performance and safety of the system.
[0054] The following describes another specific embodiment of the flue gas purification and CO2 capture and coupling system of the present invention with reference to Figure 2.
[0055] Compared to the embodiment shown in Figure 1, as shown in Figure 2, the flue gas purification and CO2 capture coupling system of another embodiment of the present invention further includes a flow control valve 20, which is used to control the ratio of flue gas discharged from the desulfurization tower 16 that enters the flue gas reheater 18 and the absorption tower 13, that is, it can control the flow rate of flue gas that enters the CO2 capture. In addition, a portion of the poor liquid discharged from the regeneration tower 6 does not return directly to the absorption tower 13 after heat exchange with the rich liquid discharged from the absorption tower 13 in the poor-to-rich liquid heat exchanger 9, but enters the flue gas reheater 18, where it heat exchanges with the decarbonized flue gas before returning to the absorption tower 13, that is, the heat of this portion of the poor liquid is reused to replenish the temperature of the discharged flue gas.
[0056] The flue gas purification and CO2 capture coupling system of the embodiment of the present invention can control the amount of flue gas entering the pre-wash tower 14 and absorption tower 13 from the desulfurization tower 16 and the amount of flue gas entering the flue gas reheater 18 from the desulfurization tower 16 by the flow control valve 20. This allows for flexible adjustment of the amount of flue gas entering the absorption tower 13 for carbon capture according to the carbon capture load capacity of the coupling system. For example, it eliminates the need to consume expensive superheated steam for carbon capture, and eliminates the need to extract steam from the power generation unit. Furthermore, it reduces the energy consumption and cost of carbon capture, avoids impact on the power generation unit, reduces the difficulty and cost of modifying conventional power generation units, and improves the coupling performance of flue gas purification and CO2 capture. On the other hand, if the carbon capture flow fails, all the flue gas can enter the flue gas reheater 18 and then be discharged from the chimney 19, without affecting the discharge of purified flue gas or the operation of the power generation unit.
[0057] Furthermore, a portion of the poor liquid discharged from the regeneration tower 6 passes through the poor-to-rich liquid heat exchanger 9 and enters the flue gas reheater 18, where it exchanges heat with the decarbonized flue gas. By utilizing the heat contained in this portion of the poor liquid to heat the decarbonized flue gas, the heat supplied to the flue gas reheater 18 by other heat sources is reduced, further lowering energy consumption and reducing the "white mist" phenomenon caused by discharge from the chimney 19. By controlling the flow rate control valve 20 so that a portion of the desulfurized flue gas enters the flue gas reheater 18, the temperature of the decarbonized flue gas can be further increased, and the "white mist" phenomenon caused by discharge from the chimney 19 can be better avoided.
[0058] For example, as shown in Figure 2, the flue gas purification and CO2 capture coupling system of an embodiment of the present invention further includes a flow meter 21 set with a flow control valve to monitor the flow rate of flue gas entering the CO2 capture equipment. The flow meter 21 is installed between the flow control valve and the blower 15. Furthermore, the flow control valve 20 may be a three-way valve, the inlet of which is connected to the outlet of the desulfurized flue gas of the desulfurization tower 16. One outlet of the three-way valve is connected to the blower 15 for supplying the desulfurized flue gas to the pre-wash tower 14, the other outlet of the three-way valve is connected to the intake of the flue gas reheater 18, and the decarbonized flue gas outlet in the absorption tower 13 is also connected to the intake of the flue gas reheater 18, and the flow meter 21 is installed between the flow control valve and the blower 15. The blower 15 can introduce the flue gas from the outlet of the desulfurization tower 16 into the pre-wash tower 14.
[0059] In some other embodiments, the flow control valve 20 may be two independently installed control valves. For example, one control valve may be located between the desulfurization flue gas outlet of the desulfurization tower 16 and the intake of the flue gas reheater 18 to control the amount of desulfurization flue gas discharged from the desulfurization tower 16 entering the flue gas reheater 18, and the other control valve may be located between the desulfurization flue gas outlet of the desulfurization tower 16 and the blower 15 to control the amount of flue gas entering the pre-wash tower 14 from the desulfurization tower 16. Of course, the two control valves must be controlled in conjunction with each other.
[0060] The embodiment of the present invention shown in Figure 2 may be the same as other embodiments of the embodiment shown in Figure 1, and will not be described further here.
[0061] The following describes the corresponding flue gas purification and CO2 capture and coupling methods of the present invention in conjunction with Example 1.
[0062] The flue gas purification and CO2 capture and coupling method of the present invention is as follows: Flue gas discharged from flue gas generators is purified by flue gas purification equipment before entering CO2 capture equipment. After CO2 capture and decarbonization, it is finally discharged to the outside, while simultaneously completing CO2 storage. The CO2 capture equipment includes an absorption tower 13 and a regeneration tower 6. The rich liquid CO2 captured in the absorption tower 13 flows into the regeneration tower 6, where it is desorbed into regenerated gas and poor liquid by heat. The regenerated gas and poor liquid are then discharged from the regeneration tower 6, respectively. A portion of the poor liquid discharged from the regeneration tower 6 undergoes heat exchange with flue gas discharged from the flue gas generator before it enters the CO2 capture equipment, becoming superheated poor liquid, and this superheated poor liquid returns to the regeneration tower to provide steam and heat for desorption.
[0063] In the flue gas purification and CO2 capture coupling method of the embodiment of the present invention, a portion of the poor liquid discharged from the regeneration tower 6 is placed in the reboiler 4 and heat is exchanged with the flue gas that has passed through the reboiler 4. After heat exchange, a portion of the poor liquid returns to the regeneration tower 6, and by utilizing the waste heat of the flue gas to heat this portion of the poor liquid in the reboiler 4, the absorbent is regenerated using the waste heat of the flue gas. This replaces some or all of the conventional steam heating, thereby avoiding the consumption of expensive superheated steam, for example, steam extracted from the power generation unit, reducing the impact on the power generation unit and lowering the energy consumption and cost of carbon capture.
[0064] Furthermore, compared to related technologies that utilize the heat exchange between the rich liquid and flue gas in the regeneration tower 6 to utilize the residual heat of the flue gas, the embodiment of the present invention utilizes the heat exchange between the poor liquid, which has a relatively low temperature and relatively low CO2 content, and the flue gas to utilize the residual heat of the flue gas to provide at least some of the heat necessary for absorbent regeneration. As a result, the poor liquid is less likely to vaporize in the piping, and because the amount of gas in the piping is small, the gas does not collide with the piping or walls, reducing the risk of leakage, reducing vibration, reducing gas etching, improving operational performance, and increasing safety. This overcomes the drawbacks of using heat exchange between the rich liquid and flue gas in related technologies. Moreover, because the temperature difference between the temperature of the poor liquid discharged from the regeneration tower 6 and the temperature of the flue gas flowing through the reboiler 4 is relatively small, the heat exchange between the two in the reboiler 4 has the advantage of reducing relative heat loss.
[0065] The following describes a specific embodiment of the present invention: a flue gas purification and CO2 capture and coupling method. This method involves the flue gas discharged from the boiler 1 passing through a denitrification tower 2, an air preheater 3, a reboiler 4, a dust collector 17, a desulfurization tower 16, and a pre-wash tower 14 in order before entering an absorption tower 13. In the absorption tower 13, CO2 is captured from the flue gas using an absorbent solution, the flue gas becomes decarbonized flue gas, which is then discharged from the top of the absorption tower 13, enters a flue gas reheater 18, and then enters a chimney 19 from the flue gas reheater 18 and is discharged to the outside.
[0066] The absorbent solution becomes a rich liquid after capturing CO2 in the absorption tower 13. The rich liquid then enters the rich liquid preheater 10, then the poor liquid heat exchanger 9, and finally the regeneration tower 6 where desorption and regeneration take place, generating regenerated gas, and the absorbent solution becomes a poor liquid.
[0067] The regenerated gas is discharged from the top of the regeneration tower 6, enters the rich liquid preheater 10, and undergoes heat exchange with the rich liquid from the absorption tower 13. After heat exchange, the regenerated gas is compressed and stored.
[0068] A portion of the poor liquid in the regeneration tower 6 is discharged from the bottom of the regeneration tower 6 and enters the poor-to-rich liquid heat exchanger 9, where it exchanges heat with the rich liquid from the rich liquid preheater 10 before entering the absorption tower 13, where it is used for CO2 absorption and collection. A portion of the poor liquid in the regeneration tower 6 is discharged from the bottom of the regeneration tower 6, pressurized, and enters the reboiler 4, where it exchanges heat with the denitrified flue gas that has passed through the reboiler 4 to form superheated poor liquid. After depressurization, the superheated poor liquid returns to the bottom of the filler in the regeneration tower 6, and some of the gas flows upward through the filler, providing steam and heat for the desorption of the rich liquid in the regeneration tower 6.
[0069] The flue gas purification and CO2 capture coupling method of the embodiment of the present invention utilizes a portion of the poor liquid discharged from the regeneration tower 6 to exchange heat with the denitrified flue gas and return it to the regeneration tower 6. This allows the residual heat of the flue gas to be used for desorption and regeneration of the absorbent, and the regenerated gas is used to exchange heat with the rich liquid discharged from the absorption tower 13. This further utilizes the heat added by the regenerated gas, thereby enhancing the thermal circulation utilization of the system. As a result, by replacing some or all of the conventional steam heating, the consumption of expensive superheated steam can be avoided, and the cost of CO2 capture can be significantly reduced.
[0070] Furthermore, by utilizing heat exchange between the poor liquid and flue gas, compared to the related technology of utilizing heat exchange between the rich liquid and flue gas in the regeneration tower 6, the poor liquid is less likely to vaporize or desorb CO2 absorbed in the piping, resulting in a smaller amount of gas in the piping, reducing the risk of pipe leakage as the gas does not collide with the piping or walls, reducing vibrations caused by collisions, reducing gas etching, resulting in better operational performance and higher safety. In addition, the poor liquid is discharged from the regeneration tower 6, first pressurized, then depressurized after heat exchange with the flue gas, and returned to the regeneration tower 6. This better reduces problems such as collisions, vibrations, and gas etching caused by the vaporization or desorption of CO2 in the piping of the poor liquid, and also allows for better utilization of the residual heat of the flue gas exchanged with the flue gas accompanied by the poor liquid.
[0071] The decarbonized flue gas passes through the flue gas reheater 18 and enters the chimney 19 for discharge, thereby reducing the "white mist" phenomenon from the chimney 19.
[0072] The following describes another specific embodiment of the present invention: a method for purifying flue gas and capturing and coupling CO2.
[0073] Compared to the above embodiment, in this other specific embodiment, instead of returning directly to the absorption tower 13 after heat exchange with the rich liquid in the poor-to-rich liquid heat exchanger 9, a portion of the poor liquid discharged from the regeneration tower 6 enters the flue gas reheater 18, where it exchanges heat with the decarbonized flue gas before returning to the absorption tower 13. This allows for better utilization of the heat attached to this portion of the poor liquid, improves the heat circulation utilization rate within the system, better avoids "white mist" from the chimney 19, and reduces the heat supply to the flue gas reheater 18 from other heat sources. On the other hand, by controlling the ratio of desulfurized flue gas entering the absorption tower 13 and the flue gas reheater 18, the amount of flue gas entering the absorption tower 13 for carbon capture can be flexibly adjusted according to the carbon capture load capacity of the coupling system. For example, it is possible to eliminate the need to consume expensive superheated steam for carbon capture, and for example, to eliminate the need to extract steam from the power generation unit. Furthermore, this reduces the energy consumption and cost of carbon capture, avoids impact on the power generation unit, lowers the difficulty and cost of modifying conventional power generation units, and improves the coupling performance of flue gas purification and carbon capture. On the other hand, if the carbon capture flow fails, all of the flue gas can enter the flue gas reheater 18 and then be discharged from the chimney 19, without affecting the discharge of purified flue gas or the operation of the power generation unit.
[0074] Another embodiment of the flue gas purification and CO2 capture and coupling method of the present invention may be the same as other embodiments of the flue gas purification and CO2 capture and coupling method of the above embodiment, and will not be described further here.
[0075] In the description of this invention, it should be understood that the directions or positional relationships indicated by terms such as "center," "vertical," "horizontal," "length," "width," "thickness," "top," "bottom," "front," "back," "left," "right," "perpendicular," "horizontal," "top," "bottom," "inside," "outside," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" are directions or positional relationships shown based on the accompanying drawings and are used solely to facilitate the description and simplification of the invention. They do not indicate or suggest that the shown devices or elements have a specific orientation or are structured and operated in a specific direction, and therefore should not be understood as limitations to the invention.
[0076] Furthermore, the terms “first” and “second” are used solely for descriptive purposes and should not be understood as indicating or implying relative importance or implicitly representing the number of technical features being referred to. Thus, features designated as “first” and “second” may explicitly or implicitly include at least one such feature. In the description of this invention, “multiple” means at least two, for example, two, three, etc., unless otherwise specifically limited.
[0077] In this invention, the terms “attached,” “connected,” “connected,” and “fixed” should be understood broadly unless otherwise explicitly stated or limited. Unless otherwise specified, for example, a fixed connection may be a detachable connection, an integrated connection may be mechanically connected, an electrically connected connection may be electrical, a direct connection may be an indirect connection via an intermediate medium, or an internal communication between two elements or an interaction relationship between two elements. Those skilled in the art will be able to understand the specific meaning of the above terms in this invention based on the specific context.
[0078] In this invention, unless otherwise explicitly stated or limited, the first feature being "above" or "below" the second feature may mean that the first and second features are in direct contact, or that they are indirectly in contact through an intermediate mediator. Furthermore, the first feature being "above," "above," and "above" the second feature may mean that the first feature is directly above or diagonally above the second feature, or that the height of the first feature level is higher than that of the second feature. The first feature being "below," "below," and "below" the second feature may mean that the first feature is directly below or diagonally below the second feature, or that the height of the first feature level is lower than that of the second feature.
[0079] In this invention, terms such as “one embodiment,” “several embodiments,” “example,” “specific example,” or “several examples” mean that the specific features, structures, materials, or characteristics described in relation to an embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the exemplary expressions of the above terms do not necessarily apply to the same embodiment or example. The specific features, structures, materials, or characteristics described may be combined in an appropriate manner in any one or more embodiments or examples. Notwithstanding the fact that those skilled in the art can link and combine different embodiments or examples and features of different embodiments or examples described herein, as long as they do not contradict each other.
[0080] Although embodiments of the present invention have been described above, these embodiments are illustrative and do not imply any limitations of the present invention. Those skilled in the art can modify, alter, substitute, and transform these embodiments within the scope of the present invention. [Explanation of Symbols]
[0081] Boiler 1, Denitration tower 2, Air preheater 3, Reboiler 4, Pressure reducing valve 5, regeneration tower 6, Pressure pump 7, 8-pack of poor fluid, poor liquid heat exchanger 9, Liquid preheater 10, CO2 compressor 11, Liquid pump 12, Absorption tower 13, Prewash tower 14, Blower 15, Desulfurization tower 16, Dust collector 17, reheater 18, Chimney 19, Flow control valve 20, Flow meter 21.
Claims
1. Flue gas purification and CO ２ A collection and coupling system comprising a flue gas generator, a flue gas purification device, and CO ２ Including a collection device, the flue gas discharged from the flue gas generating device is purified by the flue gas purification device before the CO ２ CO enters the collection device. ２ After being captured and decarbonized, CO2 is ultimately released into the environment. ２ The separation and storage of the CO2 is completed, and here, ２ The collection equipment includes an absorption tower and a regeneration tower, and CO2 is collected within the absorption tower. ２ The rich liquid from which the CO2 has been collected flows into the regeneration tower and is desorbed into regeneration gas and poor liquid by heat, and the regeneration gas and poor liquid are discharged from the regeneration tower, and a portion of the poor liquid discharged from the bottom of the regeneration tower is the CO2 discharged from the flue gas generator. ２ The flue gas, which is not present in the collection equipment, undergoes heat exchange to become a superheated, poor liquid, and this superheated, poor liquid returns to the regeneration tower, providing steam and heat for the desorption process. The regeneration tower has an inlet for lean liquid and a lean liquid outlet located at the bottom of the regeneration tower. The inlet for lean liquid is lower than the filler in the regeneration tower and higher than the liquid level of the lean liquid tank at the bottom of the regeneration tower. The CO ２ The collection equipment includes a reboiler, a pressure pump, and a pressure reducing valve. The pressure pump is provided between the regeneration tower and the reboiler and is adjacent to the lean liquid outlet of the regeneration tower. The pressure reducing valve is provided between the reboiler and the regeneration tower and is adjacent to the inlet for lean liquid of the regeneration tower. The flue gas generated by the flue gas generating equipment passes through the reboiler and exchanges heat with a part of the lean liquid. The pressure pump is used to pressurize a part of the lean liquid to raise its boiling point. The pressure reducing valve is used to reduce the pressure of the superheated lean liquid after it passes through the reboiler and exchanges heat with the flue gas to lower the boiling point of the superheated lean liquid. Here, the superheated lean liquid after pressure reduction returns to the regeneration tower through the inlet for lean liquid and releases steam. A flue gas purification and CO ２ collection and combination system, characterized in that.
2. The flue gas generating device includes a boiler and an air preheater, and the flue gas discharged from the boiler passes through the air preheater and then exchanges heat with a portion of the poor liquid, characterized in that the flue gas purification and CO2 purification described in 1 are performed. ２ Collection and coupling system.
3. The aforementioned CO ２ The collection device further includes a rich-liquid heat exchanger, where the rich liquid discharged from the absorption tower passes through the rich-liquid heat exchanger and enters the regeneration tower, and the rest of the poor liquid discharged from the regeneration tower enters the rich-liquid heat exchanger, exchanges heat with the rich liquid flowing through the rich-liquid heat exchanger, and then enters the absorption tower. and / or the flue gas purification equipment includes a denitrification tower and a desulfurization tower, and the flue gas discharged from the boiler passes through the denitrification tower, the air preheater and the desulfurization tower and enters the absorption tower, CO ２ Flue gas purification and CO2 purification according to claim 2, characterized in that after collection and decarbonization, it becomes a decarbonized flue gas and is discharged to the outside from inside the absorption tower. ２ Collection and coupling system.
4. The aforementioned pressurizing pump pressurizes a portion of the poor liquid discharged from the regeneration tower to 3-7 atmospheres. and / or, the pressure reducing valve reduces the pressure of the superheated poor liquid discharged from the reboiler to 1.2-2.0 atmospheres. And / or, in the portion of the poor liquid returned to the regeneration column after depressurization, the mass percentage of the gas phase relative to the total returned poor liquid is 2%-15%. The flue gas purification and CO2 purification according to claim 3, characterized in that the mass percentage of the portion of the poor liquid to the total poor liquid discharged from the regeneration tower is 20% to 60%. ２ Collection and coupling system.
5. The aforementioned CO ２ The collection equipment further includes a rich liquid preheater, and the rich liquid generated from the absorption tower passes sequentially through the rich liquid preheater and the poor liquid heat exchanger before entering the regeneration tower, and the regenerated gas generated from the regeneration tower enters the rich liquid preheater and exchanges heat with the rich liquid that has passed through the rich liquid preheater. and / or the CO ２ The collection equipment further includes a flue gas reheater, and the remaining portion of the poor liquid discharged from the regeneration tower passes sequentially through the rich-poor-rich liquid heat exchanger and the flue gas reheater before entering the absorption tower, and the decarbonized flue gas discharged from the absorption tower enters the flue gas reheater, exchanges heat with the poor liquid that has passed through the flue gas reheater, and is then discharged to the outside, characterized in that the flue gas purification and CO2 collection equipment according to claim 3 further includes a flue gas reheater, the remaining portion of the poor liquid discharged from the regeneration tower passes sequentially through the rich-poor-rich liquid heat exchanger and the flue gas reheater before entering the absorption tower, and the decarbonized flue gas discharged from the absorption tower enters the flue gas reheater, exchanges heat with the poor liquid that has passed through the flue gas reheater, and is then discharged to the outside ２ Collection and coupling system.
6. The aforementioned CO ２ The collection device further includes a flow control valve, which is used to control the ratio of flue gas discharged from the desulfurization tower to enter the flue gas reheater and the absorption tower, and / or a flow meter set with the flow control valve is further installed, characterized in that the flue gas purification and CO2 collection device according to claim 5 is further characterized in that the collection device further includes a flow control valve, which is used to control the ratio of flue gas discharged from the desulfurization tower to enter the flue gas reheater and the absorption tower, and / or a flow meter set with the flow control valve is further installed. ２ Collection and coupling system.
7. The flue gas purification equipment further includes a pre-wash tower, a dust collector, and a chimney, and the CO ２ CO collection equipment ２ The compressor further includes, wherein the dust collector is located between the reboiler and the desulfurization tower and is used to remove dust from the flue gas coming out of the reboiler, and the CO ２ The compressor is connected to the rich liquid preheater and compresses the regenerated gas that has undergone heat exchange with the rich liquid in the rich liquid preheater. and / or, the flue gas purification equipment further includes two flow control valves and a blower, the blower being installed between the desulfurization flue gas outlet of the desulfurization tower and the prewash tower, one of the control valves being installed between the desulfurization flue gas outlet of the desulfurization tower and the intake of the flue gas reheater to control the amount of desulfurization flue gas discharged from the desulfurization tower entering the flue gas reheater, the other control valve being installed between the desulfurization flue gas outlet of the desulfurization tower and the blower to control the amount of flue gas entering the prewash tower from the desulfurization tower, and the two control valves being controlled in conjunction, characterized in that the flue gas purification and CO2 purification according to claim 5 ２ Collection and coupling system.
8. Flue gas purification and CO2 purification according to any one of claims 1 to 7 ２ A collection and coupling system is employed to purify the flue gas and CO ２ The collection and binding method is, Flue gas discharged from flue gas generating equipment is purified by flue gas purification equipment before CO2 is released. ２ CO enters the collection device. ２ After being captured and decarbonized, CO2 is ultimately released into the environment. ２ The storage of the CO2 has been completed, ２ The collection equipment includes an absorption tower and a regeneration tower, and CO2 is collected within the absorption tower. ２ The rich liquid collected flows into the regeneration tower and is desorbed into regeneration gas and poor liquid by heat, and the regeneration gas and poor liquid are discharged from the regeneration tower, respectively. A portion of the poor liquid discharged from the bottom of the regeneration tower is the CO2 discharged from the flue gas generator. ２ The CO2 is heated and becomes a superheated, poor liquid through heat exchange with the flue gas before it enters the collection equipment, and this superheated, poor liquid returns to the regeneration tower, providing steam and heat for the desorption process, thereby removing the CO2 discharged from the flue gas generator. ２ The flue gas before it enters the collection device is the CO ２ The collection device passes through a reboiler and exchanges heat with a portion of the poor liquid, The process involves pressurizing a portion of the poor liquid discharged from the regeneration tower to raise its boiling point, and the portion of the poor liquid after pressurization is the CO2 discharged from the flue gas generator. ２ It involves heat exchange with flue gas that is not present in the collection device, Flue gas purification and CO2 purification are characterized by the following: reducing the pressure of the superheated poor liquid to lower its boiling point, and returning the superheated poor liquid after the pressure reduction to the bottom of the filler in the regeneration tower. ２ Collection and binding method.
9. A portion of the poor liquid discharged from the regeneration tower is pressurized to raise its boiling point, and a portion of the pressurized poor liquid is then used to collect the CO2 discharged from the flue gas generator. ２ Flue gas purification and CO2 purification according to claim 8, characterized in that the flue gas not in the collection device is heat-exchanged, the superheated poor liquid is depressurized to lower its boiling point, and the superheated poor liquid after depressurization is returned to the regeneration tower. ２ Collection and binding method.
10. Flue gas purification and CO2 purification according to claim 9, characterized in that the rich liquid discharged from the absorption tower is sequentially heat-exchanged with the regenerated gas discharged from the regenerated tower and the rest of the poor liquid discharged from the regenerated tower before being flowed into the regenerated tower. ２ Collection and binding method.
11. Flue gas purification and CO2 purification according to claim 10, further comprising passing the flue gas discharged from the flue gas generator through denitrification, air preheating, heat exchange with a portion of the poor liquid discharged from the regeneration tower, dust removal, and desulfurization in that order, a portion of the desulfurized flue gas and the remaining portion of the poor liquid discharged from the regeneration tower and after heat exchange with the rich liquid together with the decarbonized flue gas discharged from the absorption tower, the remaining portion of the poor liquid after heat exchange with the decarbonized flue gas flowing into the absorption tower, a portion of the desulfurized flue gas and the decarbonized flue gas after heat exchange with the remaining portion of the poor liquid being discharged to the outside, and another portion of the desulfurized flue gas entering the absorption tower. ２ Collection and binding method.
12. Flue gas purification and CO2 purification according to claim 11, characterized by controlling the ratio of a portion of the desulfurized flue gas that exchanges heat with the decarbonized flue gas to another portion of the desulfurized flue gas that enters the absorption tower. ２ Collection and binding method.