Aluminum anode carbon flue gas carbon capture system and method

Abstract

The present invention discloses a carbon capture system and method for flue gas from aluminum anode carbon, comprising: a photovoltaic-steam turbine combined power generation device, a flue gas treatment device, and a carbon capture device; the flue gas treatment device includes an ammonia storage tank, a urea storage tank, a calciner, a roaster, an electric precipitator, a heat exchanger, a catalytic reactor, a desulfurization tower, a CO catalytic bed, and a wet dust collector; the carbon capture device includes a second waste heat boiler, a reaction tower, a second condenser, a compressor, and a carbon storage tank. The present invention utilizes a photovoltaic-steam turbine combined power generation system to achieve cascaded energy utilization and low-carbon emissions, effectively reducing the overall energy consumption ratio of the carbon capture system. The introduction of devices such as the electric precipitator, catalytic reactor, and desulfurization tower significantly improves the separation purity and recovery rate of carbon dioxide. A steam purge method is used to effectively enhance the gas driving force, thereby accelerating the desorption process of carbon dioxide and improving desorption efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon capture, and in particular to a system and method for capturing carbon from flue gas produced by anode carbon for aluminum. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] One of the major sources of carbon emissions is the oxidation and combustion of fossil fuels in the industrial sector, particularly the emission of carbon dioxide (CO2). Fossil fuels, as carbon-containing compounds, are primarily composed of elements such as carbon (C), hydrogen (H), oxygen (O), nitrogen (N), and sulfur (S). During combustion, incomplete oxidation of fossil fuels releases flue gases containing CO2, of which CO2 accounts for approximately 20%. This CO2 release into the atmosphere significantly enhances the greenhouse effect and has a profound impact on global climate change.

[0004] Therefore, the use of carbon capture and storage (CCS) technology to efficiently separate and capture carbon dioxide from flue gases produced by combustion is one of the key strategies to mitigate greenhouse gas emissions and achieve carbon neutrality goals. Carbon dioxide capture and storage technology (CCS) is a technical process designed to separate CO2 from industrial emission sources or point sources and transport it to designated locations via pipelines or ships for geological storage or utilization. The main components of this technology include the capture, transportation, and final compression and injection storage of CO2. Among them, the CO2 capture link is the starting point and key bottleneck of the entire CCS value chain. Due to the high cost of the CO2 capture link, which accounts for about 70% of the total cost of CCS technology, the development of efficient and low-cost capture technology is crucial to reducing the overall carbon emission reduction cost and promoting the commercialization and popularization of CCS technology.

[0005] Existing industrial flue gas carbon capture technologies rely heavily on fossil fuels, using energy-intensive combustion processes as their power source. This results in high system energy consumption, which not only increases operating costs but also reduces the carbon emission benefits of carbon capture over its lifecycle. Furthermore, the purity of carbon dioxide separated during the capture process is generally low, limiting the storage or utilization of CO2. Furthermore, the absorbent regeneration efficiency of carbon capture systems is low, reducing the absorbent's recyclability and increasing system operating costs and energy consumption. Summary of the Invention

[0006] In order to solve the above problems, the present invention proposes a carbon capture system and method for anode carbon flue gas for aluminum, which utilizes photovoltaic-steam turbine combined power generation to achieve cascade utilization of energy and low-carbon emissions, effectively reducing the comprehensive energy consumption ratio of the carbon capture system; and introduces electric tar collectors, catalytic reactors, desulfurization towers and other devices to significantly improve the separation purity and recovery rate of carbon dioxide, and adopts a steam purge method to effectively enhance the gas driving force, thereby accelerating the desorption process of carbon dioxide and improving the desorption efficiency.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a carbon capture system for flue gas from an aluminum anode carbon, comprising:

[0009] A power generation device, a flue gas treatment device, and a carbon capture device, wherein the power generation device is connected to the flue gas treatment device and the carbon capture device respectively; the power generation device includes a first waste heat boiler, a steam turbine, a first condenser, and a deaerator, wherein the first waste heat boiler is connected to the steam turbine via a first steam pipeline, the output end of the steam turbine is connected to the first condenser, the output end of the first condenser is connected to the deaerator, and the output end of the deaerator is connected to the first waste heat boiler to form a water circulation loop;

[0010] The flue gas treatment device includes an ammonia storage tank, a urea storage tank, a calciner, a roaster, an electric tar collector, a heat exchanger, a catalytic reactor, a desulfurization tower, a CO catalytic bed, and a wet dust collector, wherein the ammonia storage tank and the urea storage tank are connected to the calciner, the roaster, and the catalytic reactor via a first delivery pipe, a second delivery pipe, and a third flue gas pipe, respectively; the electric tar collector is connected to the catalytic reactor via the heat exchanger; the catalytic reactor is connected to the desulfurization tower via a flue gas exhaust pipe; the output end of the desulfurization tower is connected to the CO catalytic bed; the output end of the CO catalytic bed is connected to the wet dust collector; and the wet dust collector is connected to the carbon capture device;

[0011] The carbon capture device includes a second waste heat boiler, a reaction tower, a second condenser, a compressor and a carbon storage tank, wherein the output end of the second waste heat boiler is connected to the reaction tower through a second air supply pipeline, the output end of the wet dust collector is connected to the reaction tower, and the output end of the reaction tower is connected to the second condenser, the compressor and the carbon storage tank in sequence.

[0012] According to a further technical solution, the power generation device also includes a photovoltaic panel, an inverter, a transformer and a cooling tower; wherein the terminal of the photovoltaic panel is connected to the inverter via a first cable, the inverter is connected to the steam turbine via a second cable, and the inverter is also connected to the transformer via a third cable; the first condenser is connected to the cooling tower via a return water pipe.

[0013] According to a further technical solution, the flue gas treatment device further includes a lime slurry storage tank and an air compressor; wherein the lime slurry storage tank is connected to the desulfurization tower, and the air compressor is connected to the CO catalytic bed through a first air supply pipeline.

[0014] According to a further technical solution, the flue gas treatment device further includes a desulfurization circulation pump, which pumps the lime slurry from the bottom of the desulfurization tower to the top of the desulfurization tower.

[0015] According to a further technical solution, the output end of the reaction tower is further connected to a first exhaust pipeline and a second exhaust pipeline, and a vacuum pump is provided on the second exhaust pipeline.

[0016] According to a further technical solution, the calcining furnace is connected to the first waste heat boiler via a first flue gas pipeline, and the first waste heat boiler is further connected to the electric tar precipitator via a second flue gas pipeline.

[0017] According to a further technical solution, the roasting furnace is connected to the second waste heat boiler via a fourth flue gas pipeline, and the second waste heat boiler is further connected to the electric tar precipitator via a third flue gas pipeline.

[0018] According to a further technical solution, the output end of the second waste heat boiler is further connected to the heat exchanger via a second steam pipeline.

[0019] In a second aspect, the present invention provides a method for capturing carbon from flue gas produced by an aluminum anode carbon, based on the aluminum anode carbon flue gas capture system described in the first aspect, comprising:

[0020] The calciner and roaster respectively receive ammonia water and urea conveyed by the first and second conveying pipelines and then perform selective non-catalytic reduction. The high-temperature flue gas generated by the calciner enters the first waste heat boiler through the first flue gas pipeline and then enters the electric tar precipitator through the second flue gas pipeline; the high-temperature flue gas generated by the roaster enters the second waste heat boiler through the fourth flue gas pipeline and then enters the electric tar precipitator through the third flue gas pipeline; the flue gas in the electric tar precipitator first enters the heat exchanger to increase the temperature and then enters the catalytic reactor for selective catalytic reduction reaction;

[0021] The flue gas after selective catalytic reduction enters the desulfurization tower for desulfurization, the flue gas after desulfurization enters the CO catalytic bed for catalytic oxidation reaction, the flue gas after catalytic oxidation enters the wet dust collector for purification, and the purified flue gas enters the reaction tower for carbon capture.

[0022] A further technical solution also includes that the carbon capture process includes a room temperature absorption stage and a desorption stage. The room temperature absorption stage is: capturing the carbon dioxide in the purified flue gas in the reaction tower, and the pure flue gas is discharged through the first exhaust pipe; the desorption stage is divided into a vacuuming stage and a steam purge stage, which are carried out in sequence. The vacuuming stage is that the vacuum pump discharges the residual flue gas in the reaction tower through the second exhaust pipe; the steam purge stage is that the high-temperature steam generated by the second waste heat boiler enters the reaction tower through the second air supply pipe, and the high-temperature steam is mixed with the carbon dioxide captured in the room temperature absorption stage, and the mixed gas enters the second condenser for cooling and separation. After separation, the carbon dioxide enters the compressor for compression, and finally the pure carbon dioxide enters the carbon storage tank for storage.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. This invention utilizes a combined photovoltaic-steam turbine power generation system. Photovoltaic panels convert solar energy into electricity. A steam turbine utilizes high-temperature, high-pressure steam to generate power, converting thermal energy into mechanical energy, which is then converted back into electricity by a generator. By combining renewable energy photovoltaic power generation with the efficient thermodynamic cycle of a steam turbine, this system achieves cascaded energy utilization and low carbon emissions, effectively reducing the overall energy consumption of the carbon capture system. Furthermore, this system utilizes a preheating boiler to recover waste heat from flue gas, further reducing system energy consumption and improving energy efficiency.

[0025] 2. This invention utilizes selective non-catalytic reduction (SNCR) and selective catalytic reduction (SCR) technologies using ammonia and urea to effectively remove nitrogen oxides from flue gas. A limestone-gypsum desulfurization process removes sulfur dioxide and other sulfides from flue gas. The catalytic oxidation of carbon monoxide to carbon dioxide increases the concentration of carbon dioxide in the flue gas, facilitating its capture in subsequent steps. This invention utilizes a series of high-efficiency flue gas purification devices and advanced gas separation processes to significantly improve the separation purity and recovery rate of carbon dioxide.

[0026] 3. This invention utilizes steam purge and vacuum desorption methods during the carbon capture process, significantly improving the desorption efficiency of carbon dioxide by enhancing the gas-phase driving force. Furthermore, the system further optimizes the regeneration performance of the absorbent within the reaction tower by regulating the gas pressure, temperature, and flow rate within the absorption tower, significantly increasing the absorbent's recycling efficiency and ensuring the stability and efficiency of the entire regeneration process. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0028] Figure 1This is a schematic structural diagram of a carbon capture system for flue gas from an aluminum anode carbon according to the present invention;

[0029] Among them, 101, photovoltaic panel; 102, inverter; 103, transformer; 104, first waste heat boiler; 105, steam turbine; 106, first fan; 107, first condenser; 108, cooling tower; 109, first water pump; 110, deaerator; 111, second water pump; 201, ammonia storage tank; 202, urea storage tank; 203, calciner; 204, roaster; 205, first centrifugal pump; 206, second centrifugal pump; 207, third centrifugal pump; 208, second fan; 209, third fan; 210, electric tar precipitator; 211, circulating Circulating pump; 212, heat exchanger; 213, catalytic reactor; 214, desulfurization tower; 215, desulfurization pump; 216, lime slurry storage tank; 217, desulfurization circulating pump; 218, CO catalytic bed; 219, air compressor; 220, wet dust collector; 301, second waste heat boiler; 302, fourth fan; 303, fifth fan; 304, reaction tower; 305, vacuum pump; 306, sixth fan; 307, second condenser; 308, compressor; 309, carbon storage tank; 4, first cable; 5, second cable; 6, third cable; 7, main cable 8. First delivery pipeline; 801. First regulating valve; 9. Second delivery pipeline; 901. Second regulating valve; 10. Third delivery pipeline; 11. Third regulating valve; 12. First flue gas pipeline; 13. Second flue gas pipeline; 131. First stop valve; 14. Third flue gas pipeline; 141. Second stop valve; 15. Fourth flue gas pipeline; 16. First steam pipeline; 17. First water supply pipeline; 171. Third stop valve; 18. Return water pipeline; 181. Fourth stop valve; 19. Flue gas exhaust pipeline; 191. First regulating valve; 192. Second regulating valve ; 193, third regulating valve; 194, fourth regulating valve; 195, fifth regulating valve; 20, second steam pipeline; 21, fifth stop valve; 22, slurry supply pipeline; 221, sixth regulating valve; 23, circulation pipeline; 231, seventh regulating valve; 24, first air supply pipeline; 25, first exhaust pipeline; 251, first exhaust valve; 26, second exhaust pipeline; 261, second exhaust valve; 27, second air supply pipeline; 271, air intake valve; 28, mixed gas exhaust pipeline; 281, third exhaust valve; 282, sixth stop valve; 283, seventh stop valve; DETAILED DESCRIPTION

[0030] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0031] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0032] In the absence of conflict, the embodiments of the present invention and the features thereof may be combined with each other.

[0033] Example 1

[0034] This embodiment provides a carbon capture system for flue gas from an aluminum anode carbon. Figure 1 The structural diagram of the flue gas carbon capture system for aluminum anode carbon is shown as follows, which includes a power generation device, a flue gas treatment device and a carbon capture device, wherein the power generation device is connected to the flue gas treatment device and the carbon capture device respectively.

[0035] like Figure 1 As shown, the power generation device is a photovoltaic-steam turbine combined power generation device, comprising: photovoltaic panels 101, inverter 102, transformer 13, first waste heat boiler 104, steam turbine 105, first condenser 107, deaerator 110, and cooling tower 108. The photovoltaic panels 101 terminals are connected to the inverter 102 via a first cable 4, the inverter 102 and steam turbine 105 are connected via a second cable 5, and the inverter 102 and transformer 103 are connected via a third cable 6. Inverter 102 converts the direct current (DC) from the photovoltaic panels 101 and steam turbine 105 into alternating current (AC), which is then adjusted by transformer 103 to meet the needs of the power consumption equipment. Transformer 103 is connected to all power consumption equipment in the system via a main cable 7. The first waste heat boiler is connected to the steam turbine through a first steam pipeline 16, and the steam turbine, the first condenser and the deaerator are connected through a first water supply pipeline 17. Specifically: the output end of the steam turbine is connected to the first condenser, the output end of the first condenser is connected to the deaerator, and the output end of the deaerator is connected to the first waste heat boiler to form a water circulation loop, wherein a first water pump 109 is provided between the first condenser and the deaerator, and a third stop valve 171 is provided between the first water pump 109 and the first condenser 107. After the high-temperature steam generated by the first waste heat boiler performs work in the steam turbine 105, the exhaust steam enters the first condenser 107 and is cooled by cooling water, and is transported to the deaerator 110 by the first water pump 109 to remove the dissolved oxygen content in the water, thereby preventing boiler corrosion, and then enters the first waste heat boiler 104 to form a water circulation loop.

[0036] The first condenser is connected to the cooling tower via a return line 18. Specifically, the output of the first condenser is connected to the input of the cooling tower, which in turn is connected back to the first condenser. A second water pump 111 is provided between the output of the cooling tower and the first condenser, and a fourth shut-off valve 181 is provided between the second water pump 111 and the cooling tower. After being heated, the cooling water in the first condenser 107 flows through the return line 18 into the cooling tower for cooling, and is then pumped back to the first condenser 107 by the first water pump 109 to continue cooling the exhaust steam.

[0037] like Figure 1 As shown, the flue gas treatment device includes: an ammonia storage tank 201, a urea storage tank 202, a calciner 203, a roaster 204, an electric tar collector 210, a heat exchanger 212, a catalytic reactor 213, a desulfurization tower 214, a lime slurry storage tank 216, a desulfurization circulation pump 217, a CO catalytic bed 218, an air compressor 219 and a wet dust collector 220. The ammonia storage tank and the urea storage tank are connected to the calciner, the roaster and the catalytic reactor through the first delivery pipe 8, the second delivery pipe 9 and the third flue gas pipe 10 respectively. Specifically, a first centrifugal pump 205 is provided on the first delivery pipe 8 and between the ammonia storage tank 201, the urea storage tank 202 and the calciner, and a first regulating valve 801 is provided between the first centrifugal pump 205 and the ammonia storage tank 201, the urea storage tank 202; on the second delivery pipe 9 and at A second centrifugal pump 206 is installed between the ammonia storage tank 201, the urea storage tank 202, and the calciner, and a second regulating valve 901 is installed between the second centrifugal pump 206 and the ammonia storage tanks 201 and urea storage tanks 202. A third centrifugal pump 207 is installed on the third delivery pipeline 10, between the ammonia storage tanks 201 and urea storage tanks 202 and the catalytic reactor, and a third regulating valve 11 is installed between the third centrifugal pump 207 and the ammonia storage tanks 201 and urea storage tanks 202. The calciner is connected to the first waste heat boiler via a first flue gas pipeline 12. The purpose is to: the high-temperature flue gas generated by the calciner 203 enters the first waste heat boiler 104 through the first flue gas pipeline 12, and the high-temperature steam generated by the first waste heat boiler 104 enters the steam turbine through the first steam pipeline 16 to generate power. The calciner is connected to the second waste heat boiler via a fourth flue gas pipeline 15. The first waste heat boiler is also connected to the electric tar precipitator via a second flue gas pipeline 13. A second fan 208 is installed on the second flue gas pipeline. A first stop valve 131 is installed between the second fan 208 and the first waste heat boiler 104. The second waste heat boiler is also connected to the electric tar precipitator via a third flue gas pipeline 14. A third fan 209 is installed on the third flue gas pipeline. A second stop valve 141 is installed between the third fan 209 and the second waste heat boiler 301. The flue gas from the first waste heat boiler 104 and the second waste heat boiler 301 enters the electric tar precipitator 210 through the second fan 208 and the third fan 209, respectively.

[0038] The electric tar collector 210, the heat exchanger 212, the catalytic reactor 213, the desulfurization tower 214, the CO catalytic bed 218 and the wet dust collector 220 are connected through a flue gas exhaust pipeline 19, wherein the electric tar collector is connected to the catalytic reactor through the heat exchanger, the catalytic reactor is connected to the desulfurization tower through the flue gas exhaust pipeline, the output end of the desulfurization tower is connected to the CO catalytic bed, the output end of the CO catalytic bed is connected to the wet dust collector, and the wet dust collector is connected to the carbon capture device. Specifically: the output end of the electric tar collector 210 is connected to the heat exchanger 212, and the output end of the second waste heat boiler is also connected to the heat exchanger through the second steam pipeline 20, the output end of the heat exchanger is connected to the catalytic reactor, and a first regulating valve 191 is provided between the heat exchanger and the catalytic reactor; the output end of the catalytic reactor is connected to the desulfurization tower, and a second regulating valve 192 is provided between the catalytic reactor 213 and the desulfurization tower 214; the output end of the desulfurization tower is connected to the CO catalytic bed. A third regulating valve 193 is provided between the desulfurization tower 214 and the CO catalytic bed 218 ; the output end of the CO catalytic bed is connected to the wet dust collector, and a fourth regulating valve 194 is provided between the CO catalytic bed 218 and the wet dust collector 220 .

[0039] A circulation pump 211 is provided on the second steam pipeline 20, and a fifth stop valve 21 is provided between the circulation pump 211 and the second waste heat boiler 301. The second steam pipeline 20 is designed because the selective catalytic reduction (SCR) of ammonia water and urea in the catalytic reactor 213 needs to be carried out in a medium temperature range of 200-450°C. The flue gas temperature from the electric tar precipitator 210 is relatively low, and heat is exchanged with the high-temperature steam from the second waste heat boiler 301 in the heat exchanger 212, thereby increasing the flue gas temperature and providing temperature conditions for the subsequent catalytic reduction reaction. The lime slurry storage tank 216 is connected to the desulfurization pump via a slurry supply line 22. A desulfurization pump 215 is installed on this line. A sixth regulating valve 221 is installed between the desulfurization pump 215 and the lime slurry storage tank 216. A circulation line 23 connects the desulfurization circulation pump 217 to the desulfurization tower 214. A seventh regulating valve 231 is installed between the desulfurization circulation pump 217 and the desulfurization tower 214. The desulfurization circulation pump pumps lime slurry from the bottom of the desulfurization tower back to the top, thereby recycling the desulfurizer and improving its utilization rate. The outlet of the air compressor 219 is connected to the inlet of the CO catalytic bed 218; the air compressor 219 and the CO catalytic bed 218 are connected via a first air supply line 24. The air compressor 219 provides high-temperature air to the CO catalytic bed 218, providing the temperature and oxygen conditions for the catalytic oxidation of CO to CO2.

[0040] like Figure 1As shown, the carbon capture device includes a second waste heat boiler 301, a reaction tower 304, a vacuum pump 305, a second condenser 307, a compressor 308 and a carbon storage tank 309, wherein the output end of the second waste heat boiler is connected to the reaction tower through a second air supply pipeline 27, the output end of the wet dust collector is connected to the reaction tower, and the output end of the reaction tower is connected to the second condenser, the compressor and the carbon storage tank in sequence. Specifically: a fifth fan 303 is provided on the second air supply pipeline 27, an air intake valve 271 is provided between the fifth fan 303 and the reaction tower 304, and the output end of the reaction tower is also connected to the first exhaust pipeline 25 and the second exhaust pipeline 26 respectively, wherein the vacuum pump 305 is provided on the second exhaust pipeline 26, and the first exhaust valve 251 is provided on the first exhaust pipeline 25, and a second exhaust valve 261 is provided between the vacuum pump and the reaction tower. The reaction tower 304, the second condenser 307, the compressor 308, and the carbon storage tank 309 are connected by a mixed gas exhaust pipeline 28. Specifically: a sixth fan 306 is provided between the output end of the reaction tower 304 and the second condenser 307, a third exhaust valve 281 is provided between the sixth fan 306 and the reaction tower 304, a sixth stop valve 282 is provided between the second condenser 307 and the compressor 308; and a seventh stop valve 283 is provided between the compressor 308 and the carbon storage tank 309.

[0041] Example 2

[0042] This embodiment provides a method for capturing carbon from flue gas produced by carbon anodes for aluminum. This method, based on the carbon capture system for flue gas produced by carbon anodes for aluminum provided in Example 1, includes the following steps: During the operation of a photovoltaic-steam turbine combined power generation device, the electricity generated by photovoltaic panels 101 and the electricity generated by the work of hot steam in steam turbine 105 flow into inverter 102 via first and second cables 4 and 5, respectively. Inverter 102 converts the electricity into alternating current (AC), which is then transmitted to a transformer via a third cable 6 for current and voltage regulation. Transformer 103 connects to various electrical devices in the system via a main cable 7 to provide power to these devices.

[0043] The high-temperature steam in the first waste heat boiler 104 is transported via the first steam pipeline 16 to the steam turbine 105 for power generation. The exhaust steam is then fed by the first fan 106 to the first condenser 107, where it is cooled by cooling water. The exhaust steam is then pumped by the first water pump 109 through the first water supply pipeline 17 to the deaerator 110, where dissolved oxygen is removed. The exhaust steam then enters the first waste heat boiler 104, forming a closed water circulation loop. The cooling water in the first condenser 107 is heated, flows through the return water pipeline 18, and then enters the cooling tower 108 for condensation. The exhaust steam is then pumped by the second water pump 111 to the first condenser 107, where it continues to cool the exhaust steam.

[0044] During the flue gas purification process, the calciner and the roaster receive ammonia water and urea transported by the first and second transport pipelines respectively and perform selective non-catalytic reduction. This process requires selective non-catalytic reduction (SNCR) of ammonia water and urea. SNCR needs to be carried out in a high temperature range of 850-1100°C, does not require a catalyst, and is suitable for being carried out in the calciner 203 or the roaster 204. The high-temperature flue gas generated by the calciner enters the first waste heat boiler through the first flue gas pipeline for heat recovery treatment, and then enters the electric tar precipitator through the second flue gas pipeline; the high-temperature flue gas generated by the roaster enters the second waste heat boiler through the fourth flue gas pipeline, and then enters the electric tar precipitator through the third flue gas pipeline; the electric tar precipitator 210 is mainly used to remove tar, asphaltene, carbon black and other hydrocarbons in the flue gas, especially organic matter generated during the high-temperature process. These substances may condense into fine particles during the flue gas cooling process. The flue gas is treated by the electric tar precipitator 210, which can effectively remove these particles and tar, preventing them from entering subsequent processing steps, thereby protecting subsequent equipment from pollution. In addition, in subsequent steps, such as selective catalytic reduction (SCR) and catalytic oxidation of CO to CO2, catalysts are required. If tar and other particulate matter are not removed, they may be deposited on the catalyst surface, resulting in reduced catalyst activity or poisoning. Therefore, it is necessary to remove these substances before catalytic steps such as SCR. After being treated by the electric tar precipitator 210, the flue gas undergoes selective catalytic reduction (SCR) of ammonia and urea to minimize the nitrogen oxide content. Since SCR needs to be carried out in a medium temperature range of 200-450°C and requires a catalyst, a temperature increase treatment is performed before the catalytic reactor 213. The flue gas from the electric tar precipitator first enters the heat exchanger for temperature increase before entering the catalytic reactor for selective catalytic reduction. Specifically, the high-temperature steam in the second waste heat boiler 301 is transported to the heat exchanger 212 by the circulating pump 211 through the second steam pipeline 20, and heat exchange is carried out with the flue gas from the electric tar precipitator 210, thereby achieving the purpose of temperature increase. Subsequently, the flue gas in the heat exchanger 212 enters the catalytic reactor 213 through the flue gas exhaust pipeline 19. At the same time, the third centrifugal pump 207 transports ammonia and urea to the catalytic reactor 213 through the third delivery pipeline 10 for selective catalytic reduction.

[0045] After the selective catalytic reduction, the flue gas enters the desulfurization tower for desulfurization. The desulfurization pump 215 transports the lime slurry to the desulfurization tower 214 through the slurry supply pipeline 22 to react with sulfur oxides. The desulfurization circulation pump 217 pumps the lime slurry from the bottom of the desulfurization tower 214 back to the top of the desulfurization tower 214, thereby realizing the recycling of the desulfurizer and improving the utilization rate of the desulfurizer. In the lime-gypsum desulfurization step, the main reaction is the reaction of calcium oxide (CaO) with sulfur dioxide (SO2) to form calcium sulfite (CaSO3), which then reacts with oxygen to form calcium sulfate (CaSO4). The side reaction is the reaction of calcium oxide with carbon dioxide to form calcium carbonate (CaCO3). In conventional flue gas components, the concentration of carbon dioxide is usually higher than that of sulfur dioxide because carbon dioxide is one of the main by-products of burning fossil fuels, while the concentration of sulfur dioxide depends on the sulfur content in the fuel and the conditions of the combustion process. Although carbon dioxide reacts with calcium oxide to form calcium carbonate (CaCO3) during this process, this reaction is not the primary purpose of the flue gas desulfurization process and is generally inefficient. This is primarily because sulfur dioxide, a stronger reducing agent, reacts much faster with calcium oxide than with carbon dioxide. Furthermore, the resulting calcium sulfite is extremely unstable, and its further oxidation to calcium sulfate is relatively rapid. The concentration of CO2 in flue gas is typically much higher than that of SO2, but due to its relatively stable chemical properties, CO2 is not easily removed. Furthermore, the reaction of CO2 with CaO is reversible, and the resulting CaCO3 can decompose back into CaO and CO2 at high temperatures. Therefore, during the flue gas desulfurization step, only small amounts of CO2 can be captured under specific conditions, such as relatively low temperatures and high CO2 partial pressures. Since carbon monoxide in flue gas is stable and generally does not react directly with calcium oxide, the catalytic oxidation of carbon monoxide to carbon dioxide is performed after the lime-gypsum desulfurization step to further mitigate side reactions. After the lime-gypsum desulfurization step, the vast majority of SO₂ in the flue gas has been removed, reducing its poisoning effect on the CO catalytic oxidation catalyst and improving the efficiency of CO conversion to CO₂. The desulfurized flue gas enters the CO catalytic bed for catalytic oxidation. After catalytic oxidation, the flue gas enters the wet dust collector for purification. The purified flue gas then enters the reaction tower for carbon capture. Specifically, flue gas from the desulfurization tower 214 enters the CO catalytic bed 218 via the flue gas exhaust line 19. Simultaneously, the air compressor 219 delivers high-temperature compressed air to the CO catalytic bed 218 via the first air supply line 24 for catalytic oxidation. After a series of treatment steps, most pollutants in the flue gas have been removed, but it may still contain fine particulate matter and residual pollutants. Wet dust removal further purifies the flue gas, ensuring more effective carbon capture. Furthermore, wet dust removal helps lower the flue gas temperature, providing optimal temperature conditions for the ambient absorption stage of carbon capture.The flue gas from the CO catalytic bed 218 enters the wet dust collector 220 through the flue gas exhaust pipeline 19 for treatment, thereby completing the flue gas purification process.

[0046] The carbon capture process includes a room-temperature absorption stage and a desorption stage. The room-temperature absorption stage involves capturing carbon dioxide from the purified flue gas in the reaction tower, and the purified flue gas is discharged through the first exhaust pipeline. Specifically, the fifth regulating valve 195 and the first exhaust valve 251 remain open, and the flue gas from the wet dust collector 220 enters the reaction tower 304 through the flue gas exhaust pipeline 19 via the fourth fan 302. After the absorbent captures carbon dioxide, the purified flue gas is discharged through the first exhaust pipeline 25. The desorption stage is divided into a vacuuming stage and a steam purge stage, which are performed sequentially. In the vacuuming stage, a vacuum pump discharges the residual flue gas in the reaction tower through the second exhaust pipeline. Specifically, the fifth regulating valve 195, the first exhaust valve 251, the air inlet valve 271, and the third exhaust valve 281 are closed, and the second exhaust valve 261 is opened. The vacuum pump 305 discharges the residual flue gas in the reaction tower 304 through the second exhaust pipeline 26. During the steam purge phase, high-temperature steam generated by the second waste heat boiler enters the reaction tower through the second air supply pipeline. The high-temperature steam mixes with the carbon dioxide captured during the normal-temperature absorption phase. The mixed gas then enters the second condenser for cooling and separation. After separation, the carbon dioxide enters the compressor for compression, and the purified carbon dioxide enters the carbon storage tank for storage. Specifically, the second exhaust valve 261, the fifth regulating valve 195, and the first exhaust valve 251 are closed, and the air inlet valve 271 and the third exhaust valve 281 are opened. High-temperature steam generated by the second waste heat boiler 301 enters the reaction tower 304 through the second air supply pipeline 27 via the fifth fan 303. After a period of time, the high-temperature steam and carbon dioxide mixture enters the second condenser 307 for cooling and separation. The mixture then enters the compressor 308 for compression through the mixed gas exhaust pipeline 28, and the purified carbon dioxide enters the carbon storage tank 309 for storage.

[0047] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

[0048] Although the above describes the specific embodiments of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without any creative work are still within the scope of protection of the present invention.

Claims

1. A carbon capture system for flue gas from an aluminum anode, characterized in that: include: A power generation device, a flue gas treatment device, and a carbon capture device, wherein the power generation device is connected to the flue gas treatment device and the carbon capture device respectively; the power generation device includes a first waste heat boiler, a steam turbine, a first condenser, and a deaerator, wherein the first waste heat boiler is connected to the steam turbine via a first steam pipeline, the output end of the steam turbine is connected to the first condenser, the output end of the first condenser is connected to the deaerator, and the output end of the deaerator is connected to the first waste heat boiler to form a water circulation loop; The flue gas treatment device includes an ammonia storage tank, a urea storage tank, a calciner, a roaster, an electric tar collector, a heat exchanger, a catalytic reactor, a desulfurization tower, a CO catalytic bed, and a wet dust collector, wherein the ammonia storage tank and the urea storage tank are connected to the calciner, the roaster, and the catalytic reactor via a first delivery pipe, a second delivery pipe, and a third flue gas pipe, respectively; the electric tar collector is connected to the catalytic reactor via the heat exchanger; the catalytic reactor is connected to the desulfurization tower via a flue gas exhaust pipe; the output end of the desulfurization tower is connected to the CO catalytic bed; the output end of the CO catalytic bed is connected to the wet dust collector; and the wet dust collector is connected to the carbon capture device; The carbon capture device includes a second waste heat boiler, a reaction tower, a second condenser, a compressor and a carbon storage tank, wherein the output end of the second waste heat boiler is connected to the reaction tower through a second air supply pipeline, the output end of the wet dust collector is connected to the reaction tower, and the output end of the reaction tower is connected to the second condenser, the compressor and the carbon storage tank in sequence.

2. The anode carbon flue gas carbon capture system for aluminum according to claim 1, characterized in that: The power generation device also includes a photovoltaic panel, an inverter, a transformer and a cooling tower; wherein the terminal of the photovoltaic panel is connected to the inverter via a first cable, the inverter is connected to the steam turbine via a second cable, and the inverter is also connected to the transformer via a third cable; the first condenser is connected to the cooling tower via a return water pipeline.

3. The anode carbon flue gas carbon capture system for aluminum according to claim 1, characterized in that: The flue gas treatment device further includes a lime slurry storage tank and an air compressor; wherein the lime slurry storage tank is connected to the desulfurization tower, and the air compressor is connected to the CO catalytic bed through a first air supply pipeline.

4. The aluminum anode carbon flue gas carbon capture system according to claim 3, characterized in that: The flue gas treatment device further comprises a desulfurization circulation pump, which pumps lime slurry from the bottom of the desulfurization tower to the top of the desulfurization tower.

5. The anode carbon flue gas carbon capture system for aluminum according to claim 1, characterized in that: The output end of the reaction tower is further connected to a first exhaust pipeline and a second exhaust pipeline respectively, and a vacuum pump is provided on the second exhaust pipeline.

6. The aluminum anode carbon flue gas carbon capture system according to claim 1, characterized in that: The calcining furnace is connected to the first waste heat boiler through a first flue gas pipeline, and the first waste heat boiler is further connected to the electric tar precipitator through a second flue gas pipeline.

7. The aluminum anode carbon flue gas carbon capture system according to claim 1, characterized in that: The roasting furnace is connected to the second waste heat boiler through a fourth flue gas pipeline, and the second waste heat boiler is further connected to the electric tar precipitator through a third flue gas pipeline.

8. The aluminum anode carbon flue gas carbon capture system according to claim 1, characterized in that: The output end of the second waste heat boiler is also connected to the heat exchanger through a second steam pipeline.

9. A method for capturing carbon from flue gas produced by an aluminum anode carbon, based on the aluminum anode carbon flue gas capture system according to any one of claims 1 to 8, characterized in that: include: The calciner and roaster respectively receive ammonia water and urea conveyed by the first and second conveying pipelines and then perform selective non-catalytic reduction. The high-temperature flue gas generated by the calciner enters the first waste heat boiler through the first flue gas pipeline and then enters the electric tar precipitator through the second flue gas pipeline; the high-temperature flue gas generated by the roaster enters the second waste heat boiler through the fourth flue gas pipeline and then enters the electric tar precipitator through the third flue gas pipeline; the flue gas in the electric tar precipitator first enters the heat exchanger to increase the temperature and then enters the catalytic reactor for selective catalytic reduction reaction; The flue gas after selective catalytic reduction enters the desulfurization tower for desulfurization, the flue gas after desulfurization enters the CO catalytic bed for catalytic oxidation reaction, the flue gas after catalytic oxidation enters the wet dust collector for purification, and the purified flue gas enters the reaction tower for carbon capture.

10. The method for capturing carbon from flue gas produced by an aluminum anode according to claim 9, wherein: It also includes that the carbon capture process includes a room temperature absorption stage and a desorption stage. The room temperature absorption stage is: capturing carbon dioxide in the purified flue gas in the reaction tower, and the pure flue gas is discharged through the first exhaust pipe; the desorption stage is divided into a vacuuming stage and a steam purge stage, which are carried out in sequence. The vacuuming stage is that the vacuum pump discharges the residual flue gas in the reaction tower through the second exhaust pipe; the steam purge stage is that the high-temperature steam generated by the second waste heat boiler enters the reaction tower through the second air supply pipe, and the high-temperature steam is mixed with the carbon dioxide captured in the room temperature absorption stage. The mixed gas enters the second condenser for cooling and separation. The separated carbon dioxide enters the compressor for compression, and finally the pure carbon dioxide enters the carbon storage tank for storage.

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