Ammonia water decarburization system and method suitable for wet desulphurization clean flue gas

Abstract

The invention discloses an ammonia water decarburization system suitable for wet desulphurization clean flue gas, the ammonia water decarburization system comprises a cooling tower, a decarburization tower, a pre-carbonization tower and a washing tower, the cooling tower is provided with a flue gas inlet and a flue gas outlet, the flue gas outlet is communicated with the decarburization tower, flue gas is suitable for entering the cooling tower for cooling through the flue gas inlet, and the pre-carbonization tower is communicated with the washing tower. The cooled flue gas enters the decarbonization tower through the flue gas outlet so as to be decarbonized through an ammonia water solution in the decarbonization tower, the decarbonized flue gas enters the pre-carbonization tower from the decarbonization tower so as to be further decarbonized through the ammonia water solution in the pre-carbonization tower, and then the decarbonized flue gas enters the washing tower from the pre-carbonization tower so as to be washed. According to the ammonia water decarburization system suitable for the wet desulphurization clean flue gas, the decarburization process is stable, the cost is saved, and the ammonia water decarburization system has great environmental protection benefits and economic benefits.

Description

Technical Field

[0001] This invention relates to the field of carbon dioxide emission reduction technology, and more specifically, to an ammonia decarbonization system and method suitable for wet desulfurization of flue gas. Background Technology

[0002] my country's energy sector has undergone transformation and restructuring. According to the *China Energy Statistical Yearbook* and data from the Ministry of Ecology and Environment, CO2 emissions from boilers (including industrial boilers and power plant boilers) account for approximately 30%–35% of the country's total emissions (around 2020 data). Decarbonizing the flue gas after desulfurization from coal-fired boilers will significantly reduce CO2 emissions. Currently, some power plants use CCUS technology to decarbonize the flue gas after desulfurization; however, how to utilize the large amount of CO2 captured has become a new problem.

[0003] Carbon capture is generally categorized into pre-combustion capture, in-combustion capture, and post-combustion capture. The first two processes are difficult to completely eliminate and are challenging to implement. Post-combustion carbon capture technology is the most mature, with relatively low construction costs, and is commonly used in coal-fired power plants. The process includes adsorption, chemical absorption, and membrane separation. Chemical absorption is the most widely used method, employing alkaline solvents such as alcohols / ammonia to capture carbon dioxide, converting it into other substances or desorbing it into pure carbon dioxide for further utilization.

[0004] However, the degradation of alkanolamines in related technologies is costly, and as chemical substances, alkanolamines are chemically unstable and prone to chemical degradation. In addition, the high concentration of carbon dioxide desorbed by the alkanolamine method has limited utilization pathways. Summary of the Invention

[0005] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, embodiments of this invention propose an ammonia decarbonization system and method suitable for wet desulfurization of flue gas.

[0006] The ammonia decarbonization system for wet desulfurization of flue gas according to embodiments of the present invention includes: Cooling towers, decarbonization towers, precarbonization towers, and scrubbing towers The cooling tower has a flue gas inlet and a flue gas outlet. The flue gas outlet is connected to the decarbonization tower. The flue gas is suitable for entering the cooling tower through the flue gas inlet for cooling. The cooled flue gas enters the decarbonization tower through the flue gas outlet for decarbonization by passing through the ammonia solution in the decarbonization tower. The decarbonized flue gas then enters the precarbonization tower for further decarbonization by passing through the ammonia solution in the precarbonization tower. Subsequently, the precarbonization tower enters the washing tower for washing.

[0007] The ammonia decarbonization system for wet desulfurization of flue gas in this embodiment of the invention involves the flue gas, after being cooled by a cooling tower, passing sequentially through a decarbonization tower and a precarbonization tower. By convection with the ammonia solution, the ammonia solution can capture carbon dioxide in the flue gas. Furthermore, the reaction between carbon dioxide and the ammonia solution can generate ammonium bicarbonate, which can be used as ammonium fertilizer or compound fertilizer in agriculture. This achieves carbon dioxide capture and resource utilization, the decarbonization process is stable, and it saves costs, resulting in significant environmental and economic benefits.

[0008] In some embodiments, the ammonia decarbonization system for wet desulfurization of flue gas further includes a cooling device, which includes a cooling circulation pump and a cooling nozzle. The cooling nozzle is located inside the cooling tower and at the top of the cooling tower, while the cooling circulation pump is located at the bottom of the cooling tower. The cooling circulation pump is used to pump the coolant in the cooling tower into the cooling nozzle.

[0009] In some embodiments, the ammonia decarbonization system suitable for wet desulfurization of flue gas further includes: An induced draft fan is provided between the cooling tower and the decarbonization tower and at the bottom of the decarbonization tower. The induced draft fan is connected to the flue gas outlet and is used to introduce the flue gas in the cooling tower into the decarbonization tower. A carbonization circulation pump is located at the bottom of the decarbonization tower and is used to pump the ammonia solution in the decarbonization tower into the top of the decarbonization tower so as to contact the flue gas in the decarbonization tower.

[0010] In some embodiments, the ammonia decarbonization system suitable for wet desulfurization of flue gas further includes: The first washing device includes a first circulating pump and a first nozzle. The first nozzle is located inside the washing tower, and the first circulating pump is located at the bottom of the washing tower for pumping the washing liquid inside the washing tower into the first nozzle. The second washing device includes a second circulation pump, a second nozzle and a first water tank. The second nozzle is located inside the washing tower and above the first nozzle. The washing liquid flowing out of the second nozzle washes the flue gas and then flows into the first water tank for storage. The second circulation pump is used to pump the washing liquid in the first water tank into the second nozzle. The third washing device includes a third circulation pump, a third nozzle, and a second water tank. The third nozzle is located inside the washing tower and above the second nozzle. The washing liquid flowing out of the third nozzle washes the flue gas and then flows into the second water tank for storage. The third circulation pump is used to pump the washing liquid in the second water tank into the third nozzle. Part of the washing liquid in the second water tank can enter the first water tank.

[0011] In some embodiments, the ammonia decarbonization system for wet desulfurization of flue gas further includes flow meters, and the flow meters are provided at the outlets of the cooling circulation pump, the carbonization circulation pump, the first circulation pump, the second circulation pump, and the third circulation pump to detect the flow rate of the solution.

[0012] In some embodiments, the ammonia decarbonization system for wet desulfurization of flue gas further includes a precarbonization circulation pump, which is located at the bottom of the precarbonization tower and is used to pump the ammonia solution in the precarbonization tower into the top of the precarbonization tower so as to contact the flue gas in the precarbonization tower.

[0013] In some embodiments, the ammonia decarbonization system suitable for wet desulfurization of flue gas further includes: The fixed valve tray is provided in both the decarbonization tower and the precarbonization tower. The fixed valve tray includes a plate body, a cover plate and support columns. The plate body has a plurality of spaced openings. A cover plate is provided on some of the openings. The cover plates and the plate body are spaced apart and connected by the support columns. A channel is formed between adjacent support columns. The channel communicates with the openings. Flue gas can be discharged sequentially through the openings and the channel. The packing material is provided in the cooling tower, the decarbonization tower, the precarbonization tower, and the scrubbing tower. Flue gas can pass through the packing material, and the packing material is arranged alternately with the fixed valve tray.

[0014] In some embodiments, the ammonia decarbonization system for wet desulfurization of flue gas further includes a crystallizer, a thickener, a centrifuge, a dryer, a packaging box, and an ammonium bicarbonate warehouse. The ammonia solution in the decarbonization tower contacts the carbon dioxide in the flue gas to generate an ammonium bicarbonate solution. The ammonium bicarbonate solution passes through the crystallizer, the thickener, the centrifuge, and the dryer in sequence to form fertilizer, which is then packaged in the packaging box and stored in the ammonium bicarbonate warehouse.

[0015] In some embodiments, the ammonia decarbonization system for wet desulfurization of flue gas further includes a liquid ammonia tank and a liquid ammonia dilution device. The liquid ammonia tank is connected to the liquid ammonia dilution device, and the liquid ammonia dilution device is connected to the cooling tower and the precarbonization tower. The liquid ammonia tank contains liquid ammonia, and the liquid ammonia in the liquid ammonia tank is diluted in the liquid ammonia dilution device and then enters the cooling tower and the precarbonization tower respectively.

[0016] The ammonia decarbonization method for wet desulfurization flue gas according to embodiments of the present invention includes: The desulfurized flue gas enters the cooling tower through the flue gas inlet for cooling. After being cooled, the flue gas enters the decarbonization tower through the flue gas outlet and comes into countercurrent contact with the ammonia solution sprayed inside the decarbonization tower to decarbonize the flue gas. After being decarbonized in the decarbonization tower, the flue gas enters the precarbonization tower and comes into countercurrent contact with the ammonia solution sprayed in the precarbonization tower to further decarbonize the flue gas. The flue gas enters the scrubbing tower from the precarbonization tower for multi-stage water scrubbing. The scrubbed flue gas meets the standards and is then discharged.

[0017] The ammonia decarbonization method for wet desulfurization of flue gas according to the embodiments of the present invention is simple, has high decarbonization efficiency, is stable, and saves costs, thus having significant environmental and economic benefits. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of an ammonia decarbonization system for wet desulfurization of flue gas according to an embodiment of the present invention.

[0019] Figure 2 This is a schematic diagram of a valve tray for an ammonia decarbonization system applicable to wet desulfurization of flue gas according to an embodiment of the present invention.

[0020] Figure 3 This is a cross-sectional view of a portion of the structure of the valve tray of an ammonia decarbonization system for wet desulfurization of flue gas, according to an embodiment of the present invention.

[0021] Reference numerals: 1. Cooling tower; 11. Flue gas inlet; 12. Flue gas outlet; 2. Decarbonization tower; 21. First air inlet; 22. First air outlet; 3. Precarbonization tower; 31. Second air inlet; 32. Second air outlet; 4. Scrubbing tower; 41. Third air inlet; 42. Third air outlet; 5. Cooling device; 51. Cooling circulation pump; 52. Cooling nozzle; 61. Exhaust fan; 62. Carbonization circulation pump; 71. First scrubbing device; 711. First circulation pump; 712. First nozzle; 72. Second scrubbing device; 721. Second circulation pump; 722. Second nozzle; 723. First water tank; 73. Third... Washing device; 731, Third circulation pump; 732, Third nozzle; 733, Second water tank; 74, Process water tank; 75, Demister flushing water pump; 76, Flow meter; 77, Pre-carbonization circulation pump; 78, Valve tray; 781, Plate body; 7811, Opening; 782, Cover plate; 783, Support column; 79, Packing; 81, Crystallizer; 82, Thickener; 83, Centrifuge; 84, Dryer; 85, Packing box; 86, Ammonium bicarbonate warehouse; 87, Crystallization pump; 88, Mother liquor tank; 89, Mother liquor pump; 91, Liquid ammonia tank; 92, Liquid ammonia dilution device; 93, MVR device; 94, Ammonia absorption device. Detailed Implementation

[0022] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0023] like Figures 1-3 As shown, the ammonia decarbonization system for wet desulfurization of flue gas according to an embodiment of the present invention includes a cooling tower 1, a decarbonization tower 2, a precarbonization tower 3, and a scrubbing tower 4. The cooling tower 1 has a flue gas inlet 11 and a flue gas outlet 12, which is connected to the decarbonization tower 2. The flue gas is suitable for entering the cooling tower 1 through the flue gas inlet 11 for cooling. The cooled flue gas enters the decarbonization tower 2 through the flue gas outlet 12 for decarbonization by passing through the ammonia solution in the decarbonization tower 2. The decarbonized flue gas then enters the precarbonization tower 3 from the decarbonization tower 2 for further decarbonization by passing through the ammonia solution in the precarbonization tower 3. Subsequently, the precarbonization tower 3 enters the scrubbing tower 4 for scrubbing.

[0024] The ammonia decarbonization system for wet desulfurization of flue gas in this embodiment of the invention involves the flue gas, after being cooled by cooling tower 1, passing sequentially through decarbonization tower 2 and precarbonization tower 3. By convection with the ammonia solution, the ammonia solution can capture carbon dioxide in the flue gas, and the reaction between carbon dioxide and the ammonia solution can generate ammonium bicarbonate, which can be used as ammonium fertilizer or compound fertilizer in agriculture. This achieves carbon dioxide capture and resource utilization, the decarbonization process is stable, and it saves costs, resulting in significant environmental and economic benefits.

[0025] Specifically, the flue gas inlet 11 is located at the bottom of the cooling tower 1, and the flue gas outlet 12 is located at the top of the cooling tower 1. The decarbonization tower 2 has a first inlet 21 and a first outlet 22. The first inlet 21 is located at the bottom of the decarbonization tower 2 and communicates with the flue gas outlet 12, while the first outlet 22 is located at the top of the decarbonization tower 2. The precarbonization tower 3 has a second inlet 31 and a second outlet 32. The second inlet 31 is located at the bottom of the precarbonization tower 3 and communicates with the first outlet 22, while the second outlet 32 ​​is located at the top of the precarbonization tower 3. The scrubbing tower 4 has a third inlet 41 and a third outlet 42. The third inlet 41 is located at the bottom of the scrubbing tower 4 and communicates with the second outlet 32, while the third outlet 42 is located at the top of the scrubbing tower 4.

[0026] In some embodiments, the ammonia decarbonization system for wet desulfurization of flue gas further includes a cooling device 5. The cooling device 5 includes a cooling circulation pump 51 and a cooling nozzle 52. The cooling nozzle 52 is disposed inside the cooling tower 1 and located at the top of the cooling tower 1. The cooling circulation pump 51 is located at the bottom of the cooling tower 1 and is used to pump the coolant in the cooling tower 1 into the cooling nozzle 52.

[0027] Specifically, flue gas enters cooling tower 1 through flue gas inlet 11, flowing from the bottom to the top of cooling tower 1. Cooling nozzles 52 spray cooling water downwards from the top of cooling tower 1, allowing the coolant to convect with the flue gas for better cooling. Cooling circulation pump 51 pumps the coolant from cooling tower 1 into cooling nozzles 52, circulating the coolant within cooling tower 1 for reuse and cost savings.

[0028] Optionally, a portion of the coolant pumped out by the cooling circulation pump 51 can enter the desulfurization unit and the scrubbing tower 4 respectively.

[0029] In some embodiments, the ammonia decarbonization system for wet desulfurization of flue gas further includes an induced draft fan 61 and a carbonization circulation pump 62. The induced draft fan 61 is located between the cooling tower 1 and the decarbonization tower 2, at the bottom of the decarbonization tower 2. The induced draft fan 61 is connected to the flue gas outlet 12 and is used to introduce the flue gas from the cooling tower 1 into the decarbonization tower 2. The carbonization circulation pump 62 is located at the bottom of the decarbonization tower 2 and is used to pump the ammonia solution from the decarbonization tower 2 to the top of the decarbonization tower 2 to contact the flue gas within the decarbonization tower 2.

[0030] Specifically, the induced draft fan 61 connects the flue gas outlet 12 and the first inlet, and is used to introduce the flue gas in the cooling tower 1 into the decarbonization tower 2. The flue gas flows from the bottom to the top of the decarbonization tower 2, and the carbonization circulation pump 62 pumps the ammonia solution in the decarbonization tower 2 from the bottom to the top, so that the sprayed ammonia solution can convect with the flue gas, enhancing the collision effect between the flue gas and the ammonia solution and improving the capture effect of the ammonia solution on carbon dioxide in the flue gas.

[0031] In some embodiments, the ammonia decarbonization system suitable for wet desulfurization of flue gas further includes a first scrubbing device 71, a second scrubbing device 72, and a third scrubbing device 73. The first scrubbing device 71 includes a first circulating pump 711 and a first nozzle 712. The first nozzle 712 is located inside the scrubbing tower 4, and the first circulating pump 711 is located at the bottom of the scrubbing tower 4, used to pump the scrubbing liquid inside the scrubbing tower 4 into the first nozzle 712. The second scrubbing device 72 includes a second circulating pump 721, a second nozzle 722, and a first water tank 723. The second nozzle 722 is located inside the scrubbing tower 4 and above the first nozzle 712. The scrubbing liquid flowing out of the second nozzle 722 scrubs the flue gas and then flows into the first water tank 723 for storage. The second circulating pump 721 is used to pump the scrubbing liquid in the first water tank 723 into the second nozzle 722. The third washing device 73 includes a third circulation pump 731, a third nozzle 732, and a second water tank 733. The third nozzle 732 is located inside the washing tower 4 and above the second nozzle 722. The washing liquid flowing out of the third nozzle 732 washes the flue gas and then flows into the second water tank 733 for storage. The third circulation pump 731 is used to pump the washing liquid in the second water tank 733 into the third nozzle 732. Part of the washing liquid in the second water tank 733 can enter the first water tank 723.

[0032] Specifically, the flue gas entering the scrubbing tower 4 through the third air inlet 41 is sequentially convected with the scrubbing liquid sprayed from the first nozzle 712, the second nozzle 722 and the third nozzle 732. The flue gas is scrubbed multiple times by the scrubbing liquid, so that the residual NH3, aerosols and other substances in the flue gas are washed to a standard state, so that they can be discharged from the third air outlet 42.

[0033] Specifically, the first circulation pump 711 pumps the washing liquid in the washing tower 4 into the first nozzle 712 for recycling. The washing liquid sprayed from the second nozzle 722 can flow into the first water tank 723. The second circulation pump 721 pumps the washing liquid in the first water tank 723 into the second nozzle 722 for recycling. In addition, the second circulation pump 721 can pump a portion of the washing liquid in the first water tank 723 into the washing tower 4 to replenish the washing liquid in the washing tower 4. The washing liquid sprayed from the third nozzle 732 can flow into the second water tank 733. The third circulation pump 731 pumps the washing liquid in the second water tank 733 into the third nozzle 732 for recycling. In addition, the third circulation pump 731 can pump a portion of the washing liquid in the second water tank 733 into the first water tank 723 to replenish the washing liquid in the first water tank 723.

[0034] In addition, a portion of the washing liquid pumped into the third nozzle 732 by the third circulation pump 731 can be pumped into the top of the precarbonization tower 3, the decarbonization tower 2 and the cooling tower 1 respectively, so as to wash the flue gas in the precarbonization tower 3, the decarbonization tower 2 and the cooling tower 1 respectively.

[0035] Optionally, the ammonia decarbonization system suitable for wet desulfurization of flue gas also includes a process water tank 74 and a demister flushing water pump 75. Demineralized water is introduced into the process water tank 74, and the demister flushing water pump 75 pumps the demineralized water in the process water tank 74 into the top of the scrubbing tower 4 to scrub the flue gas in the scrubbing tower 4, so as to ensure that the residual NH3, aerosols and other substances in the flue gas can be scrubbed to the standard state.

[0036] In some embodiments, the ammonia decarbonization system suitable for wet desulfurization of flue gas further includes a flow meter 76. The outlets of the cooling circulation pump 51, the carbonization circulation pump 62, the first circulation pump 711, the second circulation pump 721, and the third circulation pump 731 are all equipped with flow meters 76 to detect the flow rate of the solution.

[0037] In some embodiments, the ammonia decarbonization system for wet desulfurization of flue gas further includes a precarbonization circulation pump 77, which is located at the bottom of the precarbonization tower 3 and is used to pump the ammonia solution in the precarbonization tower 3 into the top of the precarbonization tower 3 so as to contact the flue gas in the precarbonization tower 3.

[0038] Specifically, the flue gas in the decarbonization tower 2 enters the precarbonization tower 3 sequentially through the first outlet 22 and the second inlet 31. The flue gas flows from the bottom to the top of the precarbonization tower 3. The precarbonization circulation pump 77 pumps the ammonia solution in the precarbonization tower 3 from the bottom to the top of the precarbonization tower 3 so that the sprayed ammonia solution can convect with the flue gas, enhance the collision effect between the flue gas and the ammonia solution, and improve the capture effect of the ammonia solution on carbon dioxide in the flue gas.

[0039] Specifically, a portion of the ammonia solution pumped out by the precarbonation circulation pump 77 can enter the decarbonization tower 2 to replenish the ammonia solution in the decarbonization tower 2.

[0040] In some embodiments, the ammonia decarbonization system suitable for wet desulfurization of flue gas further includes a valve tray 78. Both the decarbonization tower 2 and the precarbonization tower 3 are equipped with valve trays 78, which include a plate body 781, a cover plate 782, and support columns 783. The plate body 781 has multiple spaced openings 7811, and a cover plate 782 is correspondingly provided on some of the openings 7811. The cover plates 782 and the plate body 781 are spaced apart and connected by support columns 783. A channel is formed between adjacent support columns 783, and the channel communicates with the openings 7811, allowing flue gas to be discharged sequentially through the openings 7811 and the channel.

[0041] Specifically, the flue gas blown out horizontally through the opening 7811 and the channel can collide with each other to form a turbulent state and come into contact with the ammonia solution, which enhances the gas-liquid mass transfer effect. When the ammonia solution falls onto the top of the cover plate 782, some droplets will break into smaller droplets and bounce back, increasing the gas-liquid mass transfer area and enhancing the rectification effect of the component on the flue gas and the crushing function of the slurry particles. Therefore, under the same resistance conditions, the constant valve tray 78 has higher efficiency.

[0042] In some embodiments, the ammonia decarbonization system suitable for wet desulfurization of flue gas further includes packing 79. The cooling tower 1, decarbonization tower 2, precarbonization tower 3 and scrubbing tower 4 are all equipped with packing 79. Flue gas can pass through the packing 79, and the packing 79 and the fixed valve plate 78 are arranged alternately.

[0043] Specifically, the packing material 79 in cooling tower 1, decarbonization tower 2, precarbonization tower 3 and washing tower 4 is at least two, and the at least two packing materials 79 are arranged at intervals. The packing material 79 can be arranged alternately with the fixed valve plate 78 to further enhance the mass transfer effect of gas and liquid in the tower.

[0044] In some embodiments, the multiple cover plates 782 are divided into multiple groups, and the multiple groups of cover plates 782 are arranged at intervals approximately along the diameter direction of the plate body 781, with an opening 7811 between two adjacent groups of cover plates 782.

[0045] In some embodiments, the ammonia decarbonization system suitable for wet desulfurization of flue gas further includes a crystallizer 81, a thickener 82, a centrifuge 83, a dryer 84, a packaging box 85, and an ammonium bicarbonate warehouse 86. The ammonia solution in the decarbonization tower 2 contacts the carbon dioxide in the flue gas to generate an ammonium bicarbonate solution. The ammonium bicarbonate solution sequentially passes through the crystallizer 81, thickener 82, centrifuge 83, and dryer 84 to form fertilizer, which is then packaged in the packaging box 85 and stored in the ammonium bicarbonate warehouse 86.

[0046] Specifically, part of the ammonium bicarbonate solution pumped out by the carbonization circulation pump 62 enters the crystallizer 81 for crystallization, enters the thickener 82 to concentrate the solid particles in the suspension, enters the centrifuge 83 to separate the solid particles from the liquid, and the solid particles enter the dryer 84 for drying to form fertilizer. The fertilizer is then packaged in the packaging box 85 and stored in the ammonium bicarbonate warehouse 86.

[0047] Specifically, the ammonia decarbonization system applicable to wet desulfurization of flue gas also includes a crystallization pump 87, which is positioned between the crystallizer 81 and the thickener 82 to pump the ammonium bicarbonate solution in the crystallizer 81 into the thickener 82.

[0048] Specifically, the ammonia decarbonization system applicable to wet desulfurization of flue gas also includes a mother liquor tank 88 and a mother liquor pump 89. The mother liquor tank 88 is connected to a thickener 82 and a centrifuge 83. The ammonia solution in the thickener 82 and centrifuge 83 can enter the mother liquor tank 88, and the mother liquor pump 89 can pump the ammonia solution in the mother liquor tank 88 into the decarbonization tower 2.

[0049] In some embodiments, the ammonia decarbonization system for wet desulfurization of flue gas further includes a liquid ammonia tank 91 and a liquid ammonia dilution device 92. The liquid ammonia tank 91 is connected to the liquid ammonia dilution device 92, and the liquid ammonia dilution device 92 is connected to the cooling tower 1 and the precarbonization tower 3. The liquid ammonia tank 91 contains liquid ammonia, and the liquid ammonia in the liquid ammonia tank 91 is diluted in the liquid ammonia dilution device 92 and then enters the cooling tower 1 and the precarbonization tower 3 respectively.

[0050] Specifically, the ammonia decarbonization system applicable to wet desulfurization of flue gas also includes an MVR device 93 and an ammonia absorption device 94. The MVR device 93 is connected to the second water tank 733 and the first circulating pump 711. Part of the washing liquid pumped out by the first circulating pump 711 and part of the washing liquid in the second water tank 733 can enter the MVR device 93, where the enriched ammonia is evaporated by MVR technology and enters the ammonia absorption device 94 for purification and reuse in the washing and purification of flue gas. The ammonia absorption device 94 then enters the precarbonization tower 3 and the liquid ammonia dilution device 92 for recycling.

[0051] The ammonia decarbonization method for wet desulfurization flue gas according to embodiments of the present invention includes: The desulfurized flue gas enters the cooling tower 1 through the flue gas inlet 11 for cooling.

[0052] After being cooled, the flue gas enters the decarbonization tower 2 through the flue gas outlet 12 and comes into countercurrent contact with the ammonia solution sprayed inside the decarbonization tower 2 to decarbonize the flue gas.

[0053] After being decarbonized in decarbonization tower 2, the flue gas enters precarbonization tower 3 and comes into countercurrent contact with the ammonia solution sprayed in precarbonization tower 3 to further decarbonize the flue gas.

[0054] The flue gas enters the scrubbing tower 4 from the precarbonization tower 3 for multi-stage water scrubbing. The scrubbed flue gas meets the standards and is then discharged.

[0055] The ammonia decarbonization method for wet desulfurization of flue gas according to the embodiments of the present invention is simple, has high decarbonization efficiency, is stable, and saves costs, thus having significant environmental and economic benefits.

[0056] Specifically, the desulfurized flue gas first enters cooling tower 1, where it is cooled to approximately 40°C by circulating cooling water before entering the carbonization tower. In the carbonization tower, it reacts with sprayed ammonia solution, generating ammonium bicarbonate solution which is then sent to the recovery process to produce solid ammonium bicarbonate. After exiting the carbonization tower, the flue gas enters pre-carbonization tower 3, where it reacts with sprayed ammonia solution. A portion of the pre-carbonized ammonia solution is pumped to the main carbonization tower for decarbonization. The flue gas exiting pre-carbonization tower 3 undergoes a three-stage water scrubbing process in scrubbing tower 4, removing residual NH3 and aerosols before being discharged in compliance with standards. The ammonia-enriched circulating scrubbing liquid evaporates ammonia using MVR device 93. The ammonia evaporated by MVR device 93 is then absorbed by water to form ammonia water, which is pumped to the main decarbonization tower, thus achieving the capture and recovery of residual ammonia from the clean flue gas.

[0057] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0058] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0059] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0060] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0061] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0062] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of the present invention.

Claims

1. An ammonia decarbonization system suitable for wet desulfurization of flue gas, characterized in that, include: Cooling tower (1), decarbonization tower (2), precarbonization tower (3), and scrubbing tower (4), The cooling tower (1) has a flue gas inlet (11) and a flue gas outlet (12). The flue gas outlet (12) is connected to the decarbonization tower (2). The flue gas is suitable to enter the cooling tower (1) through the flue gas inlet (11) for cooling. The cooled flue gas enters the decarbonization tower (2) through the flue gas outlet (12) for decarbonization through the ammonia solution in the decarbonization tower (2). The decarbonized flue gas enters the precarbonization tower (3) from the decarbonization tower (2) for further decarbonization through the ammonia solution in the precarbonization tower (3). Then, the precarbonization tower (3) enters the washing tower (4) for washing.

2. The ammonia decarbonization system for wet desulfurization of flue gas according to claim 1, characterized in that, It also includes a cooling device (5), which includes a cooling circulation pump (51) and a cooling nozzle (52). The cooling nozzle (52) is located inside the cooling tower (1) and at the top of the cooling tower (1). The cooling circulation pump (51) is located at the bottom of the cooling tower (1). The cooling circulation pump (51) is used to pump the coolant in the cooling tower (1) into the cooling nozzle (52).

3. The ammonia decarbonization system for wet desulfurization of flue gas according to claim 2, characterized in that, Also includes: An induced draft fan (61) is provided between the cooling tower (1) and the decarbonization tower (2) and is located at the bottom of the decarbonization tower (2). The induced draft fan (61) is connected to the flue gas outlet (12) and is used to introduce the flue gas in the cooling tower (1) into the decarbonization tower (2). A carbonization circulation pump (62) is provided at the bottom of the decarbonization tower (2) to pump the ammonia solution in the decarbonization tower (2) into the top of the decarbonization tower (2) so as to contact the flue gas in the decarbonization tower (2).

4. The ammonia decarbonization system for wet desulfurization of flue gas according to claim 3, characterized in that, Also includes: The first washing device (71) includes a first circulating pump (711) and a first nozzle (712). The first nozzle (712) is located inside the washing tower (4). The first circulating pump (711) is located at the bottom of the washing tower (4) and is used to pump the washing liquid in the washing tower (4) into the first nozzle (712). The second washing device (72) includes a second circulation pump (721), a second nozzle (722) and a first water tank (723). The second nozzle (722) is located inside the washing tower (4) and above the first nozzle (712). The washing liquid flowing out of the second nozzle (722) washes the flue gas and then flows into the first water tank (723) for storage. The second circulation pump (721) is used to pump the washing liquid in the first water tank (723) into the second nozzle (722). The third washing device (73) includes a third circulation pump (731), a third nozzle (732), and a second water tank (733). The third nozzle (732) is located inside the washing tower (4) and above the second nozzle (722). The washing liquid flowing out of the third nozzle (732) washes the flue gas and then flows into the second water tank (733) for storage. The third circulation pump (731) is used to pump the washing liquid in the second water tank (733) into the third nozzle (732). Part of the washing liquid in the second water tank (733) can enter the first water tank (723).

5. The ammonia decarbonization system for wet desulfurization of flue gas according to claim 4, characterized in that, It also includes flow meters (76), which are provided at the outlets of the cooling circulation pump (51), the carbonization circulation pump (62), the first circulation pump (711), the second circulation pump (721), and the third circulation pump (731) to detect the flow rate of the solution.

6. The ammonia decarbonization system for wet desulfurization of flue gas according to claim 1, characterized in that, It also includes a pre-carbonization circulation pump (77), which is located at the bottom of the pre-carbonization tower (3) and is used to pump the ammonia solution in the pre-carbonization tower (3) into the top of the pre-carbonization tower (3) so as to contact the flue gas in the pre-carbonization tower (3).

7. The ammonia decarbonization system for wet desulfurization of flue gas according to claim 1, characterized in that, Also includes: A valve tray (78) is provided in both the decarbonization tower (2) and the precarbonization tower (3). The valve tray (78) includes a plate body (781), a cover plate (782), and a support column (783). The plate body (781) is provided with a plurality of spaced openings (7811). A cover plate (782) is provided on some of the openings (7811). The cover plate (782) and the plate body (781) are spaced apart and connected by the support column (783). A channel is formed between adjacent support columns (783). The channel is connected to the openings (7811). Flue gas can be discharged through the openings (7811) and the channel in sequence. The packing (79) is provided in the cooling tower (1), the decarbonization tower (2), the precarbonization tower (3) and the washing tower (4). Flue gas can pass through the packing (79). The packing (79) and the fixed valve plate (78) are arranged alternately.

8. The ammonia decarbonization system for wet desulfurization of flue gas according to claim 1, characterized in that, It also includes a crystallizer (81), a thickener (82), a centrifuge (83), a dryer (84), a packaging box (85), and an ammonium bicarbonate warehouse (86). The ammonia solution in the decarbonation tower (2) comes into contact with carbon dioxide in the flue gas to generate an ammonium bicarbonate solution. The ammonium bicarbonate solution passes through the crystallizer (81), the thickener (82), the centrifuge (83), and the dryer (84) in sequence to form fertilizer. It is then packaged in the packaging box (85) and stored in the ammonium bicarbonate warehouse (86).

9. The ammonia decarbonization system for wet desulfurization of flue gas according to claim 1, characterized in that, It also includes a liquid ammonia tank (91) and a liquid ammonia dilution device (92). The liquid ammonia tank (91) is connected to the liquid ammonia dilution device (92). The liquid ammonia dilution device (92) is connected to the cooling tower (1) and the pre-carbonization tower (3). The liquid ammonia tank (91) contains liquid ammonia. The liquid ammonia in the liquid ammonia tank (91) is diluted in the liquid ammonia dilution device (92) and then enters the cooling tower (1) and the pre-carbonization tower (3) respectively.

10. A method for ammonia decarbonization of flue gas suitable for wet desulfurization, characterized in that, include: The desulfurized flue gas enters the cooling tower (1) through the flue gas inlet (11) for cooling; After being cooled, the flue gas enters the decarbonization tower (2) through the flue gas outlet (12) and comes into countercurrent contact with the ammonia solution sprayed inside the decarbonization tower (2) to decarbonize the flue gas; After being decarbonized in the decarbonization tower (2), the flue gas enters the precarbonization tower (3) and comes into countercurrent contact with the ammonia solution sprayed in the precarbonization tower (3) to further decarbonize the flue gas; The flue gas enters the scrubbing tower (4) from the precarbonization tower (3) for multi-stage water scrubbing. The scrubbing flue gas meets the standards and is then discharged.

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