Anode carbon flue gas carbon capture system and method for aluminum

Abstract

The invention discloses an aluminum anode carbon flue gas carbon capture system and method. The system comprises a photovoltaic-steam turbine combined power generation device, a flue gas treatment device and a carbon capture device, the flue gas treatment device comprises an ammonia storage tank, a urea storage tank, a calcining furnace, a roasting furnace, an electrical tar precipitator, a heat exchanger, a catalytic reactor, a desulfurizing tower, a CO catalytic bed layer and a wet dust collector; and the carbon capture device comprises a second waste heat boiler, a reaction tower, a second condenser, a compressor and a carbon storage tank. According to the invention, photovoltaic-steam turbine combined power generation is utilized, so that gradient utilization and low-carbon emission of energy are realized, and the comprehensive energy consumption ratio of the carbon capture system is effectively reduced; according to the invention, the carbon dioxide is used as a raw material, the electrical tar precipitator, the catalytic reactor, the desulfurization tower and other devices are introduced, the separation purity and recovery rate of the carbon dioxide are obviously improved, and the gas driving force is effectively enhanced by adopting a steam purging method, so that the desorption process of the carbon dioxide is accelerated and the desorption efficiency is improved.

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 using 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 important sources of carbon emissions is the oxidation and combustion of fossil fuels in the industrial sector, especially the emission of carbon dioxide (CO2). Fossil fuels, as a carbon-containing compound, are mainly composed of elements such as carbon (C), hydrogen (H), oxygen (O), nitrogen (N) and sulfur (S). During the combustion process, the incomplete oxidation of fossil fuels will release flue gas containing CO2, of which carbon dioxide accounts for about 20%. These CO2 emissions into the atmosphere significantly enhance the greenhouse effect and have 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 a designated location 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 which 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] The existing industrial flue gas carbon capture technology is highly dependent on fossil fuels and uses a high-energy combustion process as a power source, resulting in a high system energy consumption ratio, which not only increases operating costs, but also reduces the carbon emission benefits of carbon capture over the life cycle; at the same time, the separation purity of carbon dioxide during the capture process is generally low, limiting the storage or utilization of CO2. In addition, the absorbent regeneration efficiency of the carbon capture system is not high, which reduces the recycling performance of the absorbent and increases the operating cost and energy consumption of the system. 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, and effectively reduce 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 solution:

[0008] In a first aspect, the present invention provides a flue gas carbon capture system for 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 comprises 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 through 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 comprises 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 through a first delivery pipe, a second delivery pipeline and a third flue gas pipeline respectively, the electric tar collector is connected to the catalytic reactor through the heat exchanger, the catalytic reactor is connected to the desulfurization tower through a 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;

[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; and the first condenser is connected to the cooling tower via a return water pipeline.

[0013] According to a further technical solution, the flue gas treatment device further comprises 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 comprises 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 also connected to a first exhaust pipeline and a second exhaust pipeline respectively, and a vacuum pump is arranged 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 also 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 using an aluminum anode carbon, based on the aluminum anode carbon flue gas carbon capture system described in the first aspect, comprising:

[0020] The calciner and roaster respectively receive ammonia water and urea transported by the first and second transport 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 to perform 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 vacuum pump stage and a steam purge stage, which are performed in sequence. The vacuum pump stage is a vacuum pump that 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. The separated 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. The present invention adopts a photovoltaic-steam turbine combined power generation device, which uses photovoltaic panels to convert solar energy into electrical energy. The steam turbine uses high-temperature and high-pressure steam to perform work, converts thermal energy into mechanical energy, and then converts it into electrical energy through a generator. By combining renewable energy photovoltaic power generation with the efficient thermal cycle of the steam turbine, the cascade utilization of energy and low carbon emissions are achieved, effectively reducing the comprehensive energy consumption ratio of the carbon capture system. In addition, the system uses a preheating boiler to recover flue gas waste heat, which further reduces the system energy consumption and improves energy utilization efficiency.

[0025] 2. The present invention uses the selective non-catalytic reduction (SNCR) and selective catalytic reduction (SCR) technologies of ammonia water and urea to effectively remove nitrogen oxides in flue gas; removes sulfur dioxide and other sulfides in flue gas through the limestone gypsum desulfurization process; and increases the concentration of carbon dioxide in flue gas through the catalytic oxidation of carbon monoxide to carbon dioxide, which helps capture carbon dioxide in subsequent steps. The present invention significantly improves the separation purity and recovery rate of carbon dioxide through a series of high-efficiency flue gas purification devices and the use of advanced gas separation processes.

[0026] 3. In the carbon capture process, the present invention adopts a steam purge method and a vacuum desorption method, which greatly improves the desorption efficiency of carbon dioxide by enhancing the gas phase driving force. In addition, the system further optimizes the regeneration performance of the absorbent in the reaction tower by adjusting the gas pressure, temperature and flow rate in the absorption tower, thereby significantly improving the recycling efficiency of the absorbent and ensuring the stability and efficiency of the entire regeneration process. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings in the specification, 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 anode carbon for aluminum 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 collector; 211, circulating Circulating pump; 212, heat exchanger; 213, catalytic reactor; 214, desulfurization tower; 215, desulfurization pump; 216, lime slurry storage tank; 217, desulfurization circulation 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 in conjunction with the accompanying drawings and embodiments.

[0031] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those 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 of the embodiments may be combined with each other.

[0033] Embodiment 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. Specifically:

[0035] like Figure 1 As shown, the power generation device is a photovoltaic-steam turbine combined power generation device, including: photovoltaic panels 101, inverters 102, transformers 13, first waste heat boilers 104, steam turbines 105, first condensers 107, deaerators 110, and cooling towers 108. Among them, the photovoltaic panel 101 terminal is connected to the inverter 102 through a first cable 4, the inverter 102 is connected to the steam turbine 105 through a second cable 5, and the inverter 102 is connected to the transformer 103 through a third cable 6. The inverter 102 converts the direct current from the photovoltaic panel 101 and the steam turbine 105 into alternating current, and then adjusts the current and voltage through the transformer 103 to meet the needs of the electrical equipment. The transformer 103 is connected to all electrical equipment in the system through the main cable 7. The first waste heat boiler is connected to the steam turbine through the first steam pipeline 16, and the steam turbine, the first condenser and the deaerator are connected through the 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 arranged between the first condenser and the deaerator, and a third stop valve 171 is arranged between the first water pump 109 and the first condenser 107. After the high-temperature steam generated by the first waste heat boiler does 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 through the return pipe 18. Specifically, the output end of the first condenser is connected to the input end of the cooling tower, the output end of the cooling tower is connected back to the first condenser, a second water pump 111 is provided between the output end of the cooling tower and the first condenser, and a fourth stop valve 181 is provided between the second water pump 111 and the cooling tower. After the cooling water in the first condenser 107 is heated, it enters the cooling tower through the return pipe 18 for cooling, and is then transported 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 pipeline 9 and the third flue gas pipeline 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 pipeline 9 and between A second centrifugal pump 206 is provided between the ammonia storage tank 201, the urea storage tank 202 and the roasting furnace, and a second regulating valve 901 is provided between the second centrifugal pump 206 and the ammonia storage tank 201, the urea storage tank 202; a third centrifugal pump 207 is provided on the third delivery pipeline 10, and between the ammonia storage tank 201, the urea storage tank 202 and the catalytic reactor, and a third regulating valve 11 is provided between the third centrifugal pump 207 and the ammonia storage tank 201, the urea storage tank 202. The calcining furnace is connected to the first waste heat boiler through the first flue gas pipeline 12, the purpose is: the high-temperature flue gas generated by the calcining furnace 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 do work; the roasting furnace is connected to the second waste heat boiler through the fourth flue gas pipeline 15. The first waste heat boiler is also connected to the electric tar precipitator through the second flue gas pipeline 13, a second fan 208 is provided on the second flue gas pipeline, a first stop valve 131 is provided between the second fan 208 and the first waste heat boiler 104, and the second waste heat boiler is also connected to the electric tar precipitator through the third flue gas pipeline 14, a third fan 209 is provided on the third flue gas pipeline, and a second stop valve 141 is provided 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 the 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 arranged 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 arranged 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 collector 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 through the slurry supply pipeline 22, and a desulfurization pump 215 is arranged on the slurry supply pipeline 22. A sixth regulating valve 221 is arranged between the desulfurization pump 215 and the lime slurry storage tank 216. The desulfurization circulation pump 217 is connected to the desulfurization tower 214 through the circulation pipeline 23. A seventh regulating valve 231 is arranged between the desulfurization circulation pump 217 and the desulfurization tower 214. The desulfurization circulation pump draws the lime slurry from the bottom of the desulfurization tower to the top of the desulfurization tower, thereby realizing the recycling of the desulfurizer and improving the utilization rate of the desulfurizer. 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 through the first air supply pipeline 24. The air compressor 219 provides high-temperature air to the CO catalytic bed 218, providing 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 arranged on the second air supply pipeline 27, an air intake valve 271 is arranged 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 arranged on the second exhaust pipeline 26, and the first exhaust valve 251 is arranged on the first exhaust pipeline 25, and a second exhaust valve 261 is arranged 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 through a mixed gas exhaust pipeline 28. Specifically: a sixth fan 306 is arranged between the output end of the reaction tower 304 and the second condenser 307, a third exhaust valve 281 is arranged between the sixth fan 306 and the reaction tower 304, a sixth stop valve 282 is arranged between the second condenser 307 and the compressor 308; and a seventh stop valve 283 is arranged between the compressor 308 and the carbon storage tank 309.

[0041] Embodiment 2

[0042] This embodiment provides a method for capturing carbon from flue gas of aluminum anode carbon, based on a system for capturing carbon from flue gas of aluminum anode carbon provided in the first embodiment, including: during the operation of the photovoltaic-steam turbine combined power generation device, the electric energy generated by the photovoltaic panel 101 and the electric energy generated by the hot steam in the steam turbine 105 flow into the inverter 102 through the first cable 4 and the second cable 5 respectively, and are converted into alternating current by the inverter 102, and then transmitted to the transformer through the third cable 6 to adjust the current and voltage. The transformer 103 is connected to each electrical device in the system through the main cable 7 to supply power to the electrical devices.

[0043] The high-temperature steam in the first waste heat boiler 104 is transported to the steam turbine 105 through the first steam pipeline 16 to perform work, and then the exhaust steam is sent to the first condenser 107 by the first fan 106 to be cooled by cooling water, and then transported to the deaerator 110 by the first water pump 109 through the first water supply pipeline 17 to remove dissolved oxygen in the water, and then enters the first waste heat boiler 104 to form a closed water circulation loop. After being heated, the cooling water in the first condenser 107 enters the cooling tower 108 through the return water pipeline 18 for condensation, and then is transported to the first condenser 107 by the second water pump 111 to continue cooling the exhaust steam.

[0044] During the flue gas purification process, the calciner and the roaster receive ammonia water and urea transported by the first delivery pipeline and the second delivery pipeline 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 collector 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 collector through the third flue gas pipeline; the electric tar collector 210 is mainly used to remove tar, asphaltene, carbon black and other hydrocarbons in the flue gas, especially organic matter produced 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 collector 210, which can effectively remove these particulate matter and tar, prevent them from entering the subsequent processing steps, and thus protect the 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 collector 210, the flue gas is subjected to selective catalytic reduction (SCR) of ammonia water and urea to minimize the content of nitrogen oxides as much as possible. Since SCR needs to be carried out in the medium temperature range of 200-450°C and requires a catalyst. Therefore, a temperature increase treatment is carried out before the catalytic reactor 213, and the flue gas in the electric tar collector first enters the heat exchanger for temperature increase and then enters the catalytic reactor for selective catalytic reduction reaction. 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 collector 210, thereby achieving the purpose of heating. 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 water and urea to the catalytic reactor 213 through the third transport pipeline 10 for selective catalytic reduction reaction.

[0045] The flue gas after selective catalytic reduction 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), and calcium sulfite 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 when burning fossil fuels, while the concentration of sulfur dioxide depends on the sulfur content in the fuel and the conditions of the combustion process. In this process, although carbon dioxide reacts with calcium oxide to form calcium carbonate (CaCO3), this reaction is not the main purpose of the flue gas desulfurization process, and its efficiency is usually not high. The main reason is that sulfur dioxide, as a strong reducing agent, reacts with calcium oxide much faster than carbon dioxide and calcium oxide, and the generated calcium sulfite is extremely unstable, and the process of further oxidation to calcium sulfate is also relatively rapid. The concentration of CO2 in flue gas is usually much higher than that of SO2, but due to the relatively stable chemical properties of CO2, it is not easy to be removed. In addition, the reaction of CO2 with CaO is reversible, and the generated CaCO3 can be decomposed into CaO and CO2 again at high temperature. Therefore, in the flue gas desulfurization step, only under specific conditions, such as lower temperature and higher CO2 partial pressure, can a small amount of CO2 be captured. Since carbon monoxide in flue gas is stable in nature and generally does not react directly with calcium oxide, the catalytic oxidation of carbon monoxide to carbon dioxide is placed after the lime-gypsum desulfurization step to further weaken the occurrence of side reactions. After the lime-gypsum desulfurization step, most of the SO2 in the flue gas has been removed, thereby reducing the poisoning effect of SO2 on the CO catalytic oxidation catalyst, thereby improving the efficiency of CO conversion to CO2. The desulfurized flue gas enters the CO catalytic bed for catalytic oxidation reaction, the catalytically oxidized flue gas enters the wet dust collector for purification, and the purified flue gas enters the reaction tower for carbon capture. Specifically: the flue gas from the desulfurization tower 214 enters the CO catalytic bed 218 through the flue gas exhaust pipeline 19, and at the same time, the air compressor 219 transports the high-temperature compressed air to the CO catalytic bed 218 through the first air supply pipeline 24 for catalytic oxidation reaction. After a series of treatment steps, most of the pollutants in the flue gas have been removed, but it may still contain tiny particles and residual pollutants. Wet dust removal can further purify the flue gas to ensure that the subsequent carbon capture step is more effective. In addition, wet dust removal helps to reduce the flue gas temperature and provides good temperature conditions for the normal temperature 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 normal temperature absorption stage and a desorption stage. The normal 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 pipeline. Specifically, the fifth regulating valve 195 and the first exhaust valve 251 remain in an open state, and the flue gas from the wet dust collector 220 enters the reaction tower 304 through the flue gas exhaust pipeline 19 through the fourth fan 302. After the absorbent captures carbon dioxide, the pure flue gas is discharged through the first exhaust pipeline 25. The desorption stage is divided into a vacuuming stage and a steam purging 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 pipeline. Specifically, the fifth regulating valve 195, the first exhaust valve 251, the air intake 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. The steam purge stage is when the high-temperature steam generated by the second waste heat boiler enters the reaction tower through the second air supply pipeline, and the high-temperature steam is mixed with the carbon dioxide captured in the normal temperature absorption stage. 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. Specifically: close the second exhaust valve 261, the fifth regulating valve 195 and the first exhaust valve 251, and open the air intake valve 271 and the third exhaust valve 281. The high-temperature steam generated by the second waste heat boiler 301 enters the reaction tower 304 through the second air supply pipeline 27 through the fifth fan 303. After a period of time, the high-temperature steam and carbon dioxide mixed gas enter the second condenser 307 for cooling and separation, and then enters the compressor 308 for compression through the mixed gas exhaust pipeline 28, and the pure carbon dioxide enters the carbon storage tank 309 for storage.

[0047] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0048] Although the above describes the specific implementation mode 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 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 comprises 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 through 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 comprises 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 through a first delivery pipe, a second delivery pipeline and a third flue gas pipeline respectively, the electric tar collector is connected to the catalytic reactor through the heat exchanger, the catalytic reactor is connected to the desulfurization tower through a 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; 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 also 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. A carbon capture system for flue gas from an aluminum anode as claimed in claim 3, characterized in that: The flue gas treatment device also includes 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 as claimed in claim 1, characterized in that: The output end of the reaction tower is also connected to a first exhaust pipeline and a second exhaust pipeline respectively, and a vacuum pump is arranged on the second exhaust pipeline.

6. The anode carbon flue gas carbon capture system for aluminum 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 also connected to the electric tar collector through a second flue gas pipeline.

7. The anode carbon flue gas carbon capture system for aluminum as claimed in 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 also connected to the electric tar precipitator through a third flue gas pipeline.

8. The anode carbon flue gas carbon capture system for aluminum as claimed in 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 using anode carbon for aluminum, based on a system for capturing carbon from flue gas using anode carbon for aluminum according to any one of claims 1 to 8, characterized in that: include: The calciner and roaster respectively receive ammonia water and urea transported by the first and second transport 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 to perform 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. A method for capturing carbon from flue gas using anode carbon for aluminum as claimed in claim 9, characterized in that: 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 pipeline; the desorption stage is divided into a vacuum pumping stage and a steam purge stage which are performed in sequence. The vacuum pumping stage is a vacuum pump that discharges the residual flue gas in the reaction tower through the second exhaust pipeline; 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 pipeline, 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. 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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