Flue gas purification and carbon capture coupling equipment

Abstract

The utility model provides flue gas purification and carbon capture coupling equipment and a flue gas purification and carbon capture coupling method. The flue gas purification and carbon capture coupling equipment comprises a boiler, a reboiler, a flue gas purification device and a carbon capture device, the boiler is connected with the flue gas purification device and the carbon capture device, the carbon capture device comprises an adsorption tower and a desorption tower, the carbon capture device comprises a pressure pump arranged between the desorption tower and the reboiler, and the adsorption tower is connected with the reboiler. The method comprises the following steps: heating and desorbing flue gas into regenerated gas and barren liquor in a desorption tower, pressurizing a part of barren liquor discharged from the desorption tower by a pressurizing pump, then exchanging heat with flue gas which is discharged from a boiler and does not enter a carbon capture device in a reboiler to become overheated barren liquor, and returning the overheated barren liquor to the desorption tower to provide steam and heat for the desorption tower, and the pressure pump is used for pressurizing the part of barren liquor to increase the boiling point of the barren liquor. Therefore, the flue gas purification and carbon capture coupling equipment disclosed by the embodiment of the utility model has the advantages of low energy consumption and capture cost and high operation stability and safety.

Description

TECHNICAL FIELD

[0001] The utility model relates to carbon capture utilization and storage (CCUS) technical field, concretely relates to a flue gas purification and carbon capture coupling equipment. BACKGROUND

[0002] Carbon capture utilization and storage (CCUS) is an important means of large-scale low-carbon utilization of fossil energy. High energy consumption and high cost are the main obstacles to the large-scale promotion of CCUS technology, and the cost of carbon capture accounts for 75% of the total chain cost. Reducing the cost of carbon capture is an international problem that needs to be solved urgently for the development of CCUS technology. The cost of capture mainly lies in the steam consumption in the regeneration process, that is, the heat required for CO2 regeneration is usually provided by superheated steam extracted from the generator set of the power plant. A large amount of steam is consumed, resulting in high carbon capture cost, and the steam cost accounts for about 50% of the total capture cost. In addition, the extraction of steam will lead to a decrease in power plant generation efficiency and an increase in power plant auxiliary load loss, further increasing the capture cost. In addition, the access of the CO2 capture system requires a large amount of modification of the original equipment system, thereby affecting the flue gas purification treatment. The related technology also proposes to use flue gas waste heat to replace the extraction of superheated steam to provide heat for the carbon capture system, but there are still many problems such as insufficient heat utilization in the system, unreasonable temperature matching, high energy consumption, etc., which affect the actual use, and therefore there is a need for improvement. CONTENT OF THE UTILITY MODEL

[0003] The utility model aims to solve one of the technical problems in the related art at least to some extent.

[0004] To this end, the utility model provides a flue gas purification and carbon capture coupling equipment. The flue gas purification and carbon capture coupling equipment has the advantages of reducing capture energy consumption.

[0005] The flue gas purification and carbon capture coupling equipment of the utility model comprises a boiler, a reboiler, a flue gas purification device and a carbon capture device, the boiler is connected with the flue gas purification device and the carbon capture device, the flue gas purification device comprises a prewashing tower, the flue gas discharged by the boiler is purified through the prewashing tower of the flue gas purification device and then enters the carbon capture device, and finally is discharged outward after CO2 capture and decarburization, and the separation and storage of CO2 are completed at the same time, wherein the carbon capture device comprises an adsorption tower and a desorption tower, the rich liquid in which CO2 is captured in the adsorption tower flows into the desorption tower and is desorbed into regenerated gas and lean liquid by heating, the regenerated gas and the lean liquid are discharged from the desorption tower, a part of the lean liquid discharged from the desorption tower exchanges heat with the flue gas discharged by the boiler and not entering the carbon capture device in the reboiler to become superheated lean liquid, and the superheated lean liquid returns to the desorption tower to provide steam and heat for the desorption tower.

[0006] In some embodiments, the flue gas cleaning and carbon capture coupling device further comprises an air preheater, wherein the flue gas discharged from the boiler exchanges heat with the portion of lean liquid after passing through the air preheater.

[0007] In some embodiments, the carbon capture device further comprises a lean-rich liquid heat exchanger, wherein the rich liquid discharged from the adsorption tower enters the desorption tower after exchanging heat with another portion of lean liquid discharged from the desorption tower in the lean-rich liquid heat exchanger, and the another portion of lean liquid enters the lean-rich liquid heat exchanger after exchanging heat with the rich liquid flowing through the lean-rich liquid heat exchanger and then enters the adsorption tower.

[0008] In some embodiments, the flue gas cleaning device comprises a denitration tower and a desulfurization tower, wherein the flue gas discharged from the boiler enters the adsorption tower after passing through the denitration tower, the air preheater and the desulfurization tower, and becomes decarbonized flue gas after CO2 capture decarbonization and is discharged from the adsorption tower.

[0009] In some embodiments, the CO2 capture device further comprises a pressurizing pump, wherein the pressurizing pump is arranged between the desorption tower and the reboiler, and is used to pressurize the portion of lean liquid to increase the boiling point thereof.

[0010] In some embodiments, the carbon capture device further comprises a depressurizing valve, wherein the depressurizing valve is arranged between the reboiler and the desorption tower and adjacent to the desorption tower, and is used to depressurize the superheated lean liquid after exchanging heat with the flue gas in the reboiler to reduce the boiling point of the superheated lean liquid, and wherein the superheated lean liquid after depressurization returns to the desorption tower and releases steam.

[0011] In some embodiments, the desorption tower has a lean liquid inlet, wherein the superheated lean liquid after depressurization returns to the desorption tower through the lean liquid inlet, and the lean liquid inlet is lower than the packing in the desorption tower and higher than the lean liquid pool liquid level of the bottom of the desorption tower.

[0012] In some embodiments, the pressurizing pump pressurizes the portion of lean liquid discharged from the desorption tower to 3-7 atmospheres.

[0013] In some embodiments, the depressurizing valve depressurizes the superheated lean liquid discharged from the reboiler to 1.2-2.0 atmospheres.

[0014] In some embodiments, among the portion of lean liquid after depressurization and returning to the desorption tower, the mass percentage of the vapor phase in the total returning lean liquid is 2%-15%.

[0015] In some embodiments, the mass percentage of the portion of lean liquid in the total lean liquid discharged from the desorption tower is 20%-60%.

[0016] In some embodiments, the carbon capture device further comprises a rich liquid preheater, the rich liquid generated in the adsorption tower enters the desorption tower in sequence through the rich liquid preheater and the lean-rich liquid heat exchanger, the regenerated gas generated in the desorption tower enters the rich liquid preheater to exchange heat with the rich liquid passing through the rich liquid preheater.

[0017] In some embodiments, the carbon capture device further comprises a flue gas reheater, the another part of the lean liquid discharged from the desorption tower enters the adsorption tower in sequence through the lean-rich liquid heat exchanger and the flue gas reheater, the decarburized flue gas discharged from the adsorption tower enters the flue gas reheater to exchange heat with the lean liquid passing through the flue gas reheater and is discharged outward.

[0018] In some embodiments, the carbon capture device further comprises a flow control valve, the flow control valve is used to control the proportion of flue gas entering the flue gas reheater and entering the adsorption tower from the desulfurization tower; and / or, a flow meter matched with the flow control valve is further arranged.

[0019] In some embodiments, the flue gas purification device further comprises a dust remover and a chimney; the carbon capture device further comprises a CO2 compressor, wherein the dust remover is arranged between the reboiler and the desulfurization tower and is used to remove dust from the flue gas coming out of the reboiler, and the CO2 compressor is connected with the rich liquid preheater to compress the regenerated gas which exchanges heat with the rich liquid in the rich liquid preheater.

[0020] In some embodiments, the flue gas purification device further comprises two flow control valves and an induced draft fan, the induced draft fan is arranged between the desulfurized flue gas outlet of the desulfurization tower and the pre-washing tower, one of the control valves is arranged between the desulfurized flue gas outlet of the desulfurization tower and the gas inlet of the flue gas reheater to control the amount of desulfurized flue gas discharged from the desulfurization tower entering the flue gas reheater, and the other control valve is arranged between the desulfurized flue gas outlet of the desulfurization tower and the induced draft fan to control the amount of flue gas entering the pre-washing tower from the desulfurization tower, and the two control valves are linked to control.

[0021] The part of the lean liquid discharged from the desorption tower is used to exchange heat with the high-temperature flue gas which does not enter the carbon capture device after leaving the flue gas generating device to form superheated lean liquid and return to the desorption tower to provide steam and heat for the CO2 regeneration reaction, the superheated lean liquid part is vaporized and returned to the desorption tower to promote the desorption of CO2 in the desorption tower, that is, the heat required for CO2 regeneration is provided by the high-temperature flue gas, the flue gas is used to heat the lean liquid to form steam to participate in the regeneration process, which can partially or even completely replace the traditional steam from the outside of the system, thereby avoiding the consumption of high-value superheated steam and effectively reducing the system energy consumption, and the capture cost per ton of CO2 can be reduced by 40%-50%.

[0022] Meanwhile, the system of the utility model is favorable for adding additional equipment when transforming existing related equipment, only needs to increase a pipeline, and the system transformation cost is greatly reduced.

[0023] In addition, the lean liquid is superheated by heat exchange with flue gas, and the superheated lean liquid is not vaporized in the reboiler in a pressurized state, so that the device vibration or cavitation phenomenon caused by gas impacting the heat exchange pipe or heat exchange wall of the reboiler can be avoided.

[0024] Therefore, the flue gas purification and carbon capture coupling device has the advantages of improving operation safety and reducing capture cost. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a schematic diagram of the flue gas purification and carbon capture coupling device of the utility model embodiment.

[0026] Figure 2 is a schematic diagram of the flue gas purification and carbon capture coupling device of another utility model embodiment.

[0027] REFERENCE NUMERALS:

[0028] Boiler 1;

[0029] Denitration tower 2;

[0030] Air preheater 3;

[0031] Reboiler 4;

[0032] Pressure reducing valve 5;

[0033] Desorption tower 6;

[0034] Pressurizing pump 7;

[0035] Lean liquid pump 8;

[0036] Lean and rich liquid heat exchanger 9;

[0037] Rich liquid preheater 10;

[0038] CO2 compressor 11;

[0039] Rich liquid pump 12;

[0040] Adsorption tower 13;

[0041] Pre-washing tower 14;

[0042] Induced draft fan 15;

[0043] Desulfurization tower 16;

[0044] Dust remover 17;

[0045] Reheater 18;

[0046] Chimney 19;

[0047] Flow control valve 20;

[0048] Flow meter 21. DETAILED DESCRIPTION

[0049] The embodiments of the present application are described in detail below, examples of which are shown in the accompanying drawings. The embodiments described below by reference to the drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0050] The flue gas purification and carbon capture coupling equipment of the embodiments of the present application is described below with reference to the accompanying drawings, wherein the flue gas comes from a power plant boiler 1. The flue gas purification and carbon capture coupling equipment refers to the coupling of a flue gas treatment system and a CO2 capture system. The flue gas discharged by the boiler 1 is subjected to CO2 capture by a CO2 absorbent solution after desulfurization and denitrification, and the flue gas after carbon capture becomes decarbonized flue gas and is discharged externally. Common CO2 absorbent solutions include but are not limited to organic amine solution, amino acid salt alkaline solution, inorganic salt alkaline solution, ionic liquid and metal organic framework solution, etc.

[0051] As Figure 1 , the flue gas purification and carbon capture coupling equipment of the embodiments of the present application includes the boiler 1, a denitration tower 2, an air preheater 3, a reboiler 4, a dust remover 17, a desulfurization tower 16, a prewashing tower 14, an adsorption tower 13, a rich-liquid preheater 10, a lean-rich liquid heat exchanger 9, a desorption tower 6, a pressurizing pump 7, a pressure reducing valve 5, a flue gas reheater 18, a chimney 19 and a CO2 compressor 11.

[0052] The flue gas discharged by the boiler 1 enters the denitration tower 2 for denitrification, and the flue gas after denitrification enters the dust remover 17 for dust removal in sequence through the air preheater 3 and the reboiler 4, and the flue gas after dust removal enters the desulfurization tower 16 for desulfurization. The flue gas after desulfurization is sent by the induced draft fan 15 into the prewashing tower 14 for prewashing, and the flue gas after prewashing enters the adsorption tower 13. The flue gas is subjected to CO2 capture by the absorbent solution (lean liquid) in the adsorption tower 13, and becomes decarbonized flue gas. The absorbent solution becomes rich liquid after capturing CO2 in the adsorption tower 13. The decarbonized flue gas is discharged from the top of the adsorption tower 13, enters the flue gas reheater 18, is reheated in the flue gas reheater 18, and then enters the chimney 19 for discharge. The rich liquid in the adsorption tower 13 is transported from the bottom of the adsorption tower 13 by the rich-liquid pump 12, flows through the rich-liquid preheater 10 and the lean-rich liquid heat exchanger 9 in sequence, and enters the desorption tower 6. The rich liquid is heated and desorbed for regeneration in the desorption tower 6, and regenerative gas is obtained. The rich liquid becomes lean liquid after desorption and regeneration, the regenerative gas enters the CO2 compressor 11 for compression and storage, and the lean liquid flows back to the adsorption tower 13 for reuse.

[0053] It is worth noting that the existing CO2 capture process has high energy consumption and operating cost in the regeneration process, and the rich liquid after the CO2 absorption is sent to the desorption tower 6 for heating and regeneration. Due to the high proportion of water in the absorbent (generally more than 70%), the heating and volatilization of water in the high-temperature CO2 desorption process will consume a large amount of energy (more than 50%). Therefore, changing the water environment of the regeneration process and reducing the participation of water in the regeneration process will be expected to maximize the use of steam heat and reduce the energy consumption of regeneration. In the conventional technology, the heat required for regeneration is usually introduced from the outside, for example, using the steam generated by the steam turbine of the power plant. This process not only needs to match the pipeline and other equipment, but also consumes superheated steam, thereby increasing the energy consumption. At the same time, the flue gas discharged from the boiler 1 has a high temperature, i.e. 350-400℃ even after passing through the denitration tower 2, and the temperature can still be maintained at 100-180℃ after passing through the air preheater, which is suitable for providing the heat required for the desorption of the rich liquid. Therefore, the reasonable use of this part of heat to obtain the heat required for the regeneration process of the absorbent will be an important means to reduce the overall energy consumption of the equipment.

[0054] In the embodiment, the steam environment of the regeneration process is changed by introducing part of the lean liquid discharged from the desorption tower 6 to exchange heat with the flue gas of the boiler 1 to form superheated liquid, thereby effectively reducing the overall energy consumption of the coupled system. The superheated lean liquid specifically refers to the superheated CO2 lean liquid maintained in a boiling state at a preset pressure, and the preset pressure generally refers to a superatmospheric pressure. Alternatively, the flue gas can come from a power plant boiler, a cement plant tail gas, a steel plant tail gas or other places that generate high-temperature flue gas.

[0055] Specifically, as shown in Figure 1 The part of the lean liquid discharged from the desorption tower 6 enters one end of the reboiler 4, and the other end of the reboiler 4 is connected to the boiler 1 through a pipeline, so that the part of the lean liquid exchanges heat with the flue gas passing through the reboiler 4 in the reboiler 4. After heat exchange, the temperature of part of the lean liquid is increased, forming a superheated lean liquid of mixed liquid steam, and the superheated lean liquid returns to the desorption tower 6 along the pipeline, and the steam in the superheated lean liquid is released to provide the heat required for the regeneration process, thereby achieving efficient use of the waste heat of the flue gas. It is worth noting that in the embodiment, the flue gas is used to heat the lean liquid to form a superheated lean liquid, and the steam in the superheated lean liquid participates in the regeneration process, which can partially or even completely replace the steam from the traditional steam turbine, thereby avoiding the consumption of high-value superheated steam. For example, the traditional CO2 rich liquid desorption needs to extract steam from the generator set to heat and desorb the rich liquid in the desorption tower. Therefore, the utility model reduces the influence on the generator set and reduces the energy consumption and cost of carbon capture.

[0056] Another part of the lean liquid discharged from the desorption tower 6 enters the lean-rich liquid heat exchanger 9 to exchange heat with the rich liquid flowing through the lean-rich liquid heat exchanger 9, and another part of the lean liquid after heat exchange enters the adsorption tower 13 to capture and absorb CO2 in the flue gas in the adsorption tower 13.

[0057] In another aspect, in the embodiment of the utility model, the flue gas generated by the power plant boiler 1 is first subjected to denitration in the denitration tower 2, the temperature of the high-temperature flue gas from the outlet of the boiler 1 can be reduced from about 800-1000℃ to about 350-400℃, and the flue gas is further cooled to about 100-180℃ by the air preheater, at this time, the flue gas still has a relatively high temperature and a relatively high available energy (enthalpy), which can be used to supplement the regeneration process with the highest energy consumption, and can be used to supplement the absorbent regeneration with the highest energy consumption. Therefore, a reboiler 4 with the function of heat collection is additionally provided, and a part of the lean liquid generated in the desorption tower 6 is extracted to exchange heat with the high-temperature flue gas after denitration in the reboiler 4 to form superheated lean liquid, and the superheated lean liquid enters the desorption tower 6 to become a gas-liquid two-phase state, in which the gas body can flow upward in the desorption tower 6 to conduct the heat carried by the gas body to the filler layer to promote the desorption reaction of CO2 in the rich liquid, thereby realizing the effective utilization of the flue gas waste heat, and the liquid phase flows to the bottom of the tower for recycling. The temperature of the flue gas flowing through the reboiler 4 is between about 100℃-180℃, and the temperature of the lean liquid discharged from the desorption tower 6 is between about 80℃-140℃, and the heat exchange temperature difference between the two should be greater than 5℃, so that the heat exchange between the two in the reboiler 4 has the advantage of reducing the relative heat loss.

[0058] On the other hand, it is worth noting that in the present embodiment, the transfer of flue gas waste heat is achieved by a portion of lean liquid drawn from the desorption tower 6. This portion of lean liquid is selected based on the fact that its temperature is relatively suitable, and based on the fact that the recycling of the lean liquid itself can reduce the additional equipment required for heat exchange, thereby reducing the difficulty of modifying the existing equipment and reducing the cost of modification. In addition, it is worth noting that in the related art, a portion of flue gas directly discharged from the boiler 1 is heated by the reboiler 4 to heat the rich liquid (45-65°C) discharged from the desorption tower 6, and the heated rich liquid is circulated back to the desorption tower 6. However, the present inventors have found and realized that, due to the relatively high temperature (generally 800-1000°C) of the flue gas from the boiler 1, the above-mentioned scheme will cause the thermal degradation of the absorbent in the rich liquid to be serious, and the rich liquid is rich in absorbed CO2, which will fill the pipeline with desorbed CO2 gas after heat exchange with the high-temperature flue gas under normal pressure. These gases not only cause noise by impacting the pipeline, but also easily cause leakage, and the pipeline is prone to scaling, which causes blockage, affects operation, and even causes major safety accidents. In comparison, the embodiment of the present application utilizes the relatively low temperature of the lean liquid and the heat exchange between the lean liquid and the flue gas to provide at least a portion of the heat required for the regeneration of the absorbent using the flue gas waste heat. Since the lean liquid is less likely to desorb CO2 in the pipeline, the amount of CO2 gas in the pipeline is small.

[0059] Further, the pipeline at the bottom of the desorption tower 6 is provided with a lean liquid pump 8 that can pressurize the lean liquid, and the portion of the lean liquid drawn will be pressurized to 3-7 atmospheres by the lean liquid pump 8. Preferably, the lean liquid pump 8 pressurizes the lean liquid to 3-6 atmospheres, so that its boiling point is lowered after being heated by the reboiler 4, and the pressurized lean liquid after heat exchange is less likely to vaporize, reducing the content of the vapor in the portion of the pipeline. The lean liquid under relatively high pressure absorbs heat from the flue gas to form superheated lean liquid, which carries the heat absorbed from the flue gas and has a temperature that can reach the desorption temperature required by the regeneration process, thereby facilitating the smooth progress of the regeneration process. Further, a portion of the lean liquid after heat exchange is provided with a pressure reduction control valve before re-entering the desorption tower 6, further reducing the pressure of the superheated lean liquid with heat to 1-2 atmospheres to lower its boiling point. Due to the lowered boiling point, a portion of the liquid in the superheated lean liquid volatilizes to become hot steam after pressure reduction, and returns to the desorption tower 6 for regeneration. Further, the mass percentage of the vapor phase in the portion of the lean liquid returned to the desorption tower 6 after pressure reduction is 2%-15% of the total returned lean liquid. If it exceeds 15%, it will cause the pipeline to be filled with too much gas, causing problems such as gas impacting the pipeline. If it is less than 2%, it will reduce the heat carried back to the desorption tower 6, thereby reducing the utilization rate of waste heat.

[0060] In another embodiment, the pressurized pump 7 is arranged adjacent to the lean liquid outlet of the desorption tower 6, and the pressure reducing valve 5 is arranged adjacent to the lean liquid inlet of the desorption tower 6, for example, the pressure reducing valve 5 can be installed at the lean liquid inlet of the desorption tower 6. The lean liquid inlet of the desorption tower 6 is located below the filler in the desorption tower 6, for example, adjacent to the bottom surface of the filler. More preferably, the lean liquid inlet is higher than the lean liquid level at the bottom of the desorption tower 6, thereby avoiding the overheated lean liquid returning to the desorption tower 6 first contacting and exchanging heat with the lean liquid below the desorption tower 6, avoiding the problem of low desorption efficiency due to the failure to fully utilize the heat carried by the part of the lean liquid for the desorption of the rich liquid, and further improving the desorption efficiency of the rich liquid.

[0061] In another embodiment, the part of the lean liquid accounts for 20%-60% of the total mass percentage of the lean liquid discharged from the desorption tower 6.

[0062] In another embodiment, the regeneration gas is discharged from the top of the desorption tower 6, and the temperature of the regeneration gas is above 60℃, that is, still has a certain amount of heat, which is guided into the rich liquid preheater 10 to exchange heat with the rich liquid from the adsorption tower 13, that is, the regeneration gas is used to heat the rich liquid flowing from the adsorption tower 13 to the desorption tower 6, thereby recovering the heat carried by the regeneration gas for adsorbent regeneration, and the regeneration gas after heat exchange with the rich liquid finally enters the CO2 compressor 11 for compression and storage.

[0063] In another embodiment, the flue gas enters the reboiler 4 before dust removal after denitrification, that is, the flue gas waste heat is utilized before dust removal after denitrification. Because the dust remover 17 is relatively difficult to handle high-temperature flue gas, the flue gas needs to be cooled to 90℃, and the temperature of the flue gas after denitrification can still be as high as 180℃, so it is relatively reasonable to set the reboiler 4 between the denitrification tower 2 and the dust remover 17 to utilize the flue gas waste heat.

[0064] In another embodiment, the decarbonized flue gas discharged from the adsorption tower 13 is heated by the flue gas reheater 18 and then enters the chimney 19 for discharge, thereby increasing the flue gas discharge temperature of the chimney 19 (generally increasing the flue gas discharge temperature to above 80℃), and reducing the phenomenon of “white smoke” of the chimney 19.

[0065] The flue gas purification and carbon capture coupling equipment of the embodiment of the utility model, the efficiency of the heat recycling of the flue gas waste heat and the heat in the system such as the heat carried by the regeneration gas and the lean liquid is improved, the steam consumption is sufficiently reduced, and the CO2 capture cost can be reduced by 40%-50%. Meanwhile, by using the system, the influence of the steam extraction on the generator set is reduced, and the additional equipment such as the steam pressure and temperature reducer is reduced. In addition, by using the heat exchange mode of the system, the problems of gas impact on the pipeline, pipeline leakage, impact vibration and cavitation in the related art are overcome, and the operation performance and safety of the system are improved.

[0066] The following will be described with reference to the accompanying drawings Figure 2The utility model discloses a flue gas purification and carbon capture coupling equipment.

[0067] With Figure 1 Compared with the embodiment shown as Figure 2 The flue gas purification and carbon capture coupling equipment of another embodiment of the utility model further includes flow control valve 20, and flow control valve 20 is used to control the proportion of flue gas from desulfurizing tower 16 into flue gas reheater 18 and into adsorption tower 13, that is, the flue gas flow into CO2 capture can be controlled.In addition, after the heat exchange between the part of lean liquid from desorption tower 6 and the rich liquid from adsorption tower 13 in lean-rich liquid heat exchanger 9, the lean liquid does not return to adsorption tower 13 directly, but returns to adsorption tower 13 after the heat exchange between the lean liquid and the decarburization flue gas in flue gas reheater 18, that is, the heat of the part of lean liquid is used again to supplement the temperature of the discharged flue gas.

[0068] The flue gas purification and carbon capture coupling equipment of the embodiment of the utility model can control the flue gas amount from desulfurizing tower 16 into prewashing tower 14 and adsorption tower 13 and the flue gas amount from desulfurizing tower 16 into flue gas reheater 18 through flow control valve 20, so that the flue gas amount into adsorption tower 13 for carbon capture can be adjusted flexibly according to the carbon capture load capacity of the coupling system, for example, the high-value superheated steam can not be consumed for carbon capture completely, for example, the steam can not be extracted from the generator set completely, the energy consumption and cost of carbon capture are further reduced, the influence on the generator set is avoided, the difficulty and cost of the modification of the existing generator set are reduced, and the coupling performance of flue gas purification and CO2 capture is improved.On the other hand, when the carbon capture process fails, the flue gas can be discharged through chimney 19 after entering flue gas reheater 18 completely, and the discharge of the purified flue gas and the operation of the generator set are not affected.

[0069] In addition, after the heat exchange between the part of lean liquid from desorption tower 6 and the rich liquid from adsorption tower 13 in lean-rich liquid heat exchanger 9, the lean liquid does not return to adsorption tower 13 directly, but returns to adsorption tower 13 after the heat exchange between the lean liquid and the decarburization flue gas in flue gas reheater 18, that is, the heat of the part of lean liquid is used again to supplement the temperature of the discharged flue gas.

[0070] For example, Figure 2As shown in the figure, the flue gas purification and carbon capture coupling device of the embodiment of the present utility model further includes a flowmeter 21 supporting the flow control valve to monitor the flow rate of the flue gas entering the carbon capture device. The flowmeter 21 is arranged between the flow control valve and the induced draft fan 15. Further, the flow control valve 20 can also be a three-way valve, and the inlet of the three-way valve is connected to the desulfurized flue gas outlet of the desulfurization tower 16. One outlet of the three-way valve is connected to the induced draft fan 15 for supplying desulfurized flue gas to the pre-scrubbing tower 14, and the other outlet of the three-way valve is connected to the inlet of the flue gas reheater 18. The outlet of the decarbonized flue gas in the adsorption tower 13 is also connected to the inlet of the flue gas reheater 18. The flowmeter 21 is arranged between the flow control valve and the induced draft fan 15. The induced draft fan 15 can introduce the flue gas at the outlet of the desulfurization tower 16 into the pre-scrubbing tower 14.

[0071] Optionally, in some other embodiments, the flow control valve 20 can also be two separately arranged control valves. For example, one control valve is arranged between the desulfurized flue gas outlet of the desulfurization tower 16 and the inlet of the flue gas reheater 18 to control the amount of desulfurized flue gas discharged from the desulfurization tower 16 entering the flue gas reheater 18, and the other control valve is arranged between the desulfurized flue gas outlet of the desulfurization tower 16 and the induced draft fan 15 to control the amount of flue gas entering the pre-scrubbing tower 14 from the desulfurization tower 16. Of course, the two control valves need to be controlled in a linked manner.

[0072] Figure 2 The embodiment of the present utility model shown in Figure 1 The remaining aspects of the shown embodiment can be the same and will not be described in detail here.

[0073] The corresponding flue gas purification and CO2 capture coupling method of the embodiment of the present utility model will be described below in conjunction with Embodiment 1.

[0074] The flue gas purification and CO2 capture coupling method of the embodiment of the present utility model includes:

[0075] The flue gas discharged from the flue gas generating device is purified by the flue gas purification device and then enters the carbon capture device. After CO2 capture and decarbonization, it is finally discharged to the outside, and at the same time, the storage of CO2 is completed. The carbon capture device includes an adsorption tower 13 and a desorption tower 6. The rich liquid that has captured CO2 in the adsorption tower 13 flows into the desorption tower 6 and is thermally desorbed into a regenerated gas and a lean liquid. The regenerated gas and the lean liquid are respectively discharged from the desorption tower 6;

[0076] A part of the lean liquid discharged from the desorption tower 6 is exchanged heat with the flue gas discharged from the flue gas generating device before entering the carbon capture device to become superheated lean liquid, and the superheated lean liquid returns to the desorption tower to provide steam and heat for the desorption tower.

[0077] The flue gas purification and CO2 capture coupling method of the embodiment of the utility model, through the part of lean liquid discharged in the desorption tower 6 enters the reboiler 4 and exchanges heat with the flue gas passing through the reboiler 4, part of the lean liquid after heat exchange returns to the desorption tower 6, namely, the part of lean liquid is heated in the reboiler 4 by using the flue gas waste heat, thereby using the flue gas waste heat to regenerate the absorbent, which can partially or even completely replace the traditional steam heating, thereby avoiding the consumption of high-value superheated steam, such as steam heating extracted from the generator set, thereby reducing the influence on the generator set, reducing the energy consumption and cost of carbon capture.

[0078] In addition, compared with the related art using the rich liquid in the desorption tower 6 to exchange heat with the flue gas to utilize the flue gas waste heat, the embodiment of the utility model uses the lean liquid with relatively low temperature and low CO2 content to exchange heat with the flue gas to utilize the flue gas waste heat to provide at least part of the heat required for absorbent regeneration, since the lean liquid is not easy to vaporize in the pipeline, the amount of gas in the pipeline is small, thereby not causing gas impact on the pipeline or wall surface, reducing the risk of leakage, reducing vibration, reducing cavitation, good running performance, high safety, thereby overcoming the defects caused by using the rich liquid to exchange heat with the flue gas in the related art. Moreover, the temperature difference between the lean liquid discharged from the desorption tower 6 and the flue gas temperature from the reboiler 4 is small, thereby the heat exchange between the two in the reboiler 4 has the advantage of reducing the relative heat loss.

[0079] The flue gas purification and CO2 capture coupling method of the embodiment of the utility model is described below, which comprises: the flue gas discharged from the boiler 1 passes through the denitration tower 2, the air preheater 3, the reboiler 4, the dust remover 17, the desulfurization tower 16 and the prewashing tower 14 in turn and enters the adsorption tower 13, the CO2 capture of the flue gas is carried out in the adsorption tower 13 by using the absorbent solution, the flue gas becomes the decarbonized flue gas and is discharged from the top of the adsorption tower 13 to enter the flue gas reheater 18, and then enters the chimney 19 from the flue gas reheater 18 to be discharged outward.

[0080] The absorbent solution becomes the rich liquid after capturing the CO2 in the adsorption tower 13, the rich liquid enters the rich liquid preheater 10, then enters the lean and rich liquid heat exchanger 9 from the rich liquid preheater 10, and then enters the desorption tower 6 for desorption and regeneration to produce the regenerated gas, and the absorbent solution becomes the lean liquid.

[0081] The regenerated gas is discharged from the top of the desorption tower 6 to enter the rich liquid preheater 10 and exchange heat with the rich liquid from the adsorption tower 13, and the regenerated gas after heat exchange is compressed and stored.

[0082] A portion of the lean liquor in desorption tower 6 is discharged from the bottom of desorption tower 6 and enters the lean-rich liquor heat exchanger 9. After exchanging heat with the rich liquor from the rich liquor preheater 10, it enters the adsorption tower 13 for CO2 absorption and capture. Another portion of the lean liquor in desorption tower 6 is discharged from the bottom of desorption tower 6, pressurized, and enters the reboiler 4. It exchanges heat with the denitrified flue gas passing through the reboiler 4 to form a superheated lean liquor. After depressurization, the superheated lean liquor returns to the bottom of the packing material in desorption tower 6, where the gas flows upward through the packing material, providing steam and heat for the desorption of the rich liquor in desorption tower 6.

[0083] The flue gas purification and CO2 capture coupling method of this utility model utilizes a portion of the lean liquid discharged from desorption tower 6 to exchange heat with the denitrified flue gas before returning it to desorption tower 6. This utilizes the waste heat of the flue gas for absorbent desorption and regeneration. Furthermore, the regenerated gas exchanges heat with the rich liquid discharged from adsorption tower 13, further utilizing the heat carried by the regenerated gas and improving the heat recycling of the equipment. This can partially or even completely replace traditional steam heating, thereby avoiding the consumption of high-value superheated steam and significantly reducing CO2 capture costs.

[0084] Furthermore, compared to the related technology that utilizes rich liquor within the desorption tower 6 for heat exchange with flue gas, the lean liquor is less prone to vaporization and desorption of absorbed CO2 within the pipeline. The smaller volume of gas in the pipeline prevents gas from impacting the pipeline or walls, reducing the risk of pipeline leakage, minimizing vibration caused by impact, and reducing cavitation. This results in better operational performance and higher safety. Moreover, the lean liquor discharged from the desorption tower 6 is first pressurized, then exchanges heat with the flue gas, and finally depressurized before returning to the desorption tower 6. This further reduces the vaporization or desorption of CO2 by the lean liquor within the pipeline, and the resulting impact, vibration, and cavitation problems. Simultaneously, it allows for better utilization of the waste heat from the flue gas exchanged with the lean liquor.

[0085] The decarbonized flue gas passes through the flue gas reheater 18 and enters the chimney 19 for emission, reducing the "white smoke" phenomenon emitted from the chimney 19.

[0086] The following describes another specific embodiment of the flue gas purification and CO2 capture coupling method of this utility model.

[0087] Compared with the above embodiment, in this another specific embodiment, a part of the lean liquid discharged from the desorption tower 6 is returned to the adsorption tower 13 after heat exchange with the rich liquid in the lean-rich liquid heat exchanger 9 and heat exchange with the flue gas after decarbonization in the flue gas reheater 18, instead of being directly returned to the adsorption tower 13, so that the heat carried by the part of the lean liquid can be better utilized, the heat recycling rate in the equipment is improved, and the "white smoke" from the chimney 19 is better avoided, and the heat supply to the flue gas reheater 18 through other heat sources is reduced. On the other hand, the proportion of the flue gas after desulfurization entering the adsorption tower 13 and the flue gas reheater 18 is controlled, so that the amount of flue gas entering the adsorption tower 13 for carbon capture can be flexibly adjusted according to the carbon capture load capacity of the coupled system, for example, the carbon capture can be completely realized without consuming high-value superheated steam, for example, completely without extracting steam from the generator set, further reducing the energy consumption and cost of carbon capture, avoiding the influence on the generator set, reducing the difficulty and cost of modification of the existing generator set, and improving the coupling performance of flue gas purification and carbon capture. On the other hand, when the carbon capture process fails, the flue gas can be discharged through the chimney 19 after entering the flue gas reheater 18, without affecting the emission of the purified flue gas and the operation of the generator set.

[0088] The flue gas purification and CO2 capture coupling method of another embodiment of the utility model can be the same as other aspects of the flue gas purification and CO2 capture coupling method of the above embodiment, which will not be described here.

[0089] In the description of the utility model, it is understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the utility model and simplifying the description, and therefore cannot be understood as indicating or implying that the indicated device or element must have a particular orientation, structure and operation, and therefore cannot be understood as limiting the utility model.

[0090] In addition, the terms "first" and "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" can explicitly or implicitly include at least one of the features. In the description of the utility model, the meaning of "multiple" is at least two, for example, two, three, etc., unless otherwise specifically limited.

[0091] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected or can communicate with each other; it can be directly connected, or it can be indirectly connected through an intermediate medium, it can be the internal communication of two elements or the interaction relationship of two elements, unless otherwise explicitly limited. For ordinary skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0092] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature. The first and second features can be in direct contact, or the first and second features can be in indirect contact through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be directly above or obliquely above the first feature, or only indicate that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature can be directly below or obliquely below the first feature, or only indicate that the horizontal height of the first feature is less than that of the second feature.

[0093] In the present application, the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, the skilled in the art can combine and combine the different embodiments or examples described in the present application and the features of the different embodiments or examples without contradiction.

[0094] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present application. The ordinary skilled in the art can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A flue gas cleaning and carbon capture coupling apparatus, characterized in that, The application relates to a flue gas purification and carbon capture coupling device. The device comprises a boiler, a reboiler, a flue gas purification device and a carbon capture device, the boiler is connected with the flue gas purification device and the carbon capture device, the flue gas purification device comprises a prewashing tower, flue gas discharged from the boiler is purified through the prewashing tower of the flue gas purification device and then enters the carbon capture device, after CO2 capture and decarburization, the flue gas is finally discharged, meanwhile, CO2 separation and storage are completed, wherein the carbon capture device comprises an adsorption tower and a desorption tower, rich liquid in which CO2 is captured flows into the desorption tower and is desorbed into regenerated gas and lean liquid by heating, the regenerated gas and the lean liquid are discharged from the desorption tower, a part of the lean liquid discharged from the desorption tower exchanges heat with flue gas discharged from the boiler and not entering the carbon capture device in the reboiler to become superheated lean liquid, and the superheated lean liquid returns to the desorption tower to provide steam and heat for the desorption tower.

2. The flue gas cleaning and carbon capture coupling device of claim 1, wherein, The device further comprises an air preheater, flue gas discharged from the boiler exchanges heat with the part of the lean liquid after passing through the air preheater.

3. The flue gas cleaning and carbon capture coupling device of claim 2, wherein, The carbon capture device further comprises a lean liquid-rich liquid heat exchanger, wherein the rich liquid discharged from the adsorption tower enters the desorption tower through the lean liquid-rich liquid heat exchanger, and another part of the lean liquid discharged from the desorption tower enters the lean liquid-rich liquid heat exchanger to exchange heat with the rich liquid flowing through the lean liquid-rich liquid heat exchanger and then enters the adsorption tower.

4. The flue gas cleaning and carbon capture coupling device of claim 3, wherein, The flue gas purification device comprises a denitration tower and a desulfurization tower, flue gas discharged from the boiler enters the adsorption tower through the denitration tower, the air preheater and the desulfurization tower, after CO2 capture and decarburization, the flue gas becomes decarburized flue gas and is discharged from the adsorption tower.

5. The flue gas purification and carbon capture coupling device according to claim 4, wherein The CO2 capture device further comprises a pressurizing pump, the pressurizing pump is arranged between the desorption tower and the reboiler, and the pressurizing pump is used for pressurizing the part of the lean liquid to increase the boiling point of the part of the lean liquid; And / or, the carbon capture device further comprises a pressure reducing valve, the pressure reducing valve is arranged between the reboiler and the desorption tower and adjacent to the desorption tower, and the pressure reducing valve is used for reducing the pressure of the superheated lean liquid after exchanging heat with the flue gas in the reboiler to reduce the boiling point of the superheated lean liquid, wherein the superheated lean liquid after pressure reduction returns to the desorption tower and releases steam.

6. The flue gas cleaning and carbon capture coupling device of claim 5, wherein, The desorption tower has a lean liquid inlet, wherein the superheated lean liquid after pressure reduction returns to the desorption tower through the lean liquid inlet, the lean liquid inlet is lower than the filler in the desorption tower and higher than the lean liquid pool liquid level of the bottom of the desorption tower.

7. The flue gas cleaning and carbon capture coupling device of claim 6, wherein, The pressurizing pump pressurizes the part of the lean liquid discharged from the desorption tower to 3-7 atm; And / or, the pressure reducing valve reduces the pressure of the superheated lean liquid discharged from the reboiler to 1.2-2.0 atm; And / or, in the part of the lean liquid after pressure reduction and returning to the desorption tower, the mass percentage of the steam phase in the total returning lean liquid is 2%-15%; And / or, the mass percentage of the part of the lean liquid in the total lean liquid discharged from the desorption tower is 20%-60%.

8. The flue gas cleaning and carbon capture coupling device of claim 7, wherein, The carbon capture device further comprises a rich liquid preheater, the rich liquid generated in the adsorption tower enters the desorption tower in sequence through the rich liquid preheater and the lean-rich liquid heat exchanger, the regenerated gas generated in the desorption tower enters the rich liquid preheater to exchange heat with the rich liquid passing through the rich liquid preheater; And / or, the carbon capture device further comprises a flue gas reheater, the another part of the lean liquid discharged from the desorption tower enters the adsorption tower in sequence through the lean-rich liquid heat exchanger and the flue gas reheater, the decarburized flue gas discharged from the adsorption tower enters the flue gas reheater to exchange heat with the lean liquid passing through the flue gas reheater and is discharged outward.

9. The flue gas cleaning and carbon capture coupling device according to claim 8, characterized in that, The carbon capture device further comprises a flow control valve, the flow control valve is used to control the proportion of flue gas entering the flue gas reheater and entering the adsorption tower from the desulfurization tower; and / or, a flow meter matched with the flow control valve is further provided.

10. The flue gas cleaning and carbon capture coupled device according to claim 8 or 9, characterized in that, The flue gas cleaning device further comprises a dust remover and a chimney, and the carbon capture device further comprises a CO2 compressor, wherein the dust remover is arranged between the reboiler and the desulfurization tower and is used to remove dust from the flue gas coming out of the reboiler, and the CO2 compressor is connected with the rich liquid preheater to compress the regenerated gas which has exchanged heat with the rich liquid in the rich liquid preheater; And / or, the flue gas cleaning device further comprises two flow control valves and an induced draft fan, the induced draft fan is arranged between the desulfurized flue gas outlet of the desulfurization tower and the pre-washing tower, one of the control valves is arranged between the desulfurized flue gas outlet of the desulfurization tower and the gas inlet of the flue gas reheater to control the amount of desulfurized flue gas discharged from the desulfurization tower entering the flue gas reheater, and the other control valve is arranged between the desulfurized flue gas outlet of the desulfurization tower and the induced draft fan to control the amount of flue gas entering the pre-washing tower from the desulfurization tower, and the two control valves are linked to control.

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