Pre-baked anode carbon capture system for industrial electrolytic aluminum and operation method

Abstract

The invention discloses a prebaked anode carbon capture system for industrial electrolytic aluminum and an operation method, and belongs to the field of carbon capture, the prebaked anode carbon capture system comprises a combined power generation device for supplying power to equipment, a flue gas treatment device and a carbon capture device; the flue gas treatment device comprises a roasting furnace and a calcining furnace, flue gas generated by the flue gas treatment device is subjected to multi-stage treatment to provide raw materials for the carbon capture device, and heat generated by the flue gas treatment device is subjected to multi-stage recycling to provide reaction conditions for flue gas treatment and drive a steam turbine to generate power; the carbon capture device comprises an absorption tower and a motor boiler, and the absorption tower receives flue gas and completes carbon capture under the assistance of steam. A series of efficient flue gas treatment units are adopted, and the purity of carbon dioxide is remarkably improved. In addition, the multi-stage regenerative cycle technology is designed, and the comprehensive utilization efficiency of heat energy is improved. And by adopting a steam-assisted vacuum temperature swing adsorption technology, the dynamic adsorption capacity of gas is enhanced, and the cycle service life of an absorbent is prolonged, so that the economical efficiency and the operating performance of the system are optimized.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon capture, and in particular to a prebaked anode carbon capture system for industrial aluminum electrolysis and an operating method. 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] Global warming and frequent extreme weather events have become severe challenges facing the world. Greenhouse gas emissions (especially carbon dioxide) continue to rise, leading to irreversible changes in the earth's climate system and exacerbating the frequency of extreme weather events and natural disasters. Among the many sources of carbon emissions, industrial flue gas emissions account for more than half of the total emissions. With the continuous growth of global demand for electricity and manufacturing, traditional carbon reduction methods such as energy conservation and emission reduction, improving energy efficiency and optimizing energy structure can no longer meet the requirements.

[0004] Carbon capture, utilization and storage (CCUS) is considered a key greenhouse gas reduction strategy worldwide. The technology involves extracting carbon dioxide (CO2) from point source emissions or the atmosphere, capturing it through chemical adsorption, physical separation or biological carbon fixation, and then converting it into economically valuable commodities or storing it through chemical conversion, biological conversion or geological storage to reduce greenhouse gas emissions. In the entire CCUS process, the capture and separation of CO2 often accounts for 40% to 70% of the total cost. This process involves the development of efficient absorbents, the design optimization of absorption towers, and the integration of energy recovery systems. According to market analysis and forecasts, by 2027, the annual output value of the global carbon capture and storage (CCS) market is expected to reach US$6.13 billion. CCUS technology is of great significance for the deep decarbonization of industrial production. It is estimated that by 2060, CCUS technology will be able to achieve a CO2 emission reduction of about 1 billion tons per year, which involves the improvement of carbon capture efficiency, the construction of transportation networks, and the safety monitoring of storage sites.

[0005] Existing industrial flue gas carbon capture technology mainly relies on fossil fuel combustion to provide energy. The overall energy consumption of the system is high and the carbon emissions are large. The high energy consumption leads to high system operating costs and poor economic benefits, which limits the promotion and application of carbon capture technology. At the same time, the traditional physical absorption method or chemical absorption method has low carbon capture efficiency. Due to the presence of various impurity gases, particulate matter and dust in industrial flue gas, the purity of the captured carbon dioxide is not high. 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 view of the above problems, the present invention proposes a prebaked anode carbon capture system and operation method for industrial electrolytic aluminum, which generates electricity by coupling photovoltaic panels with steam turbines to provide sustainable power supply for the entire system. A series of high-efficiency flue gas treatment units are used to significantly improve the purity of carbon dioxide. In addition, a multi-stage heat recovery cycle technology is designed to improve the comprehensive utilization efficiency of thermal energy. In the carbon capture subsystem, steam-assisted vacuum temperature swing adsorption technology is used to enhance the dynamic adsorption capacity of the gas, significantly improve the recycling efficiency of the absorption tower, and reduce the energy consumption in the CO2 desorption process. And extend the cycle service life of the absorbent, thereby optimizing the economy and operating performance of the system.

[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 prebaked anode carbon capture system for industrial aluminum electrolysis, comprising a combined power generation device, wherein the combined power generation device is connected to a flue gas treatment device and a carbon capture device, respectively, to supply power to electrical equipment of the flue gas treatment device and the carbon capture device;

[0009] The flue gas treatment device includes a roaster and a calciner. The flue gas generated by the roaster and the calciner is subjected to multi-stage treatment to provide raw materials for the carbon capture device. The heat generated by the roaster is recycled and utilized in multiple stages to provide reaction conditions for the flue gas treatment process. The heat generated by the calciner is used to heat the waste heat boiler to generate steam to drive the steam turbine for power generation, and is used to heat the heat transfer oil to the required temperature.

[0010] The carbon capture device comprises an absorption tower and a motor boiler. The absorption tower receives the flue gas that has been processed in multiple stages and completes carbon capture and adsorption with the assistance of high-temperature steam generated by the motor boiler.

[0011] As a further implementation method, part of the flue gas generated by the calcining furnace enters the waste heat boiler through the third flue gas pipeline for heat exchange, and the flue gas after heat exchange enters the quenching and tempering tower through the third flue gas pipeline, and the other part enters the second heat exchanger through the second flue gas pipeline for heat exchange with the heat transfer oil, and the flue gas after heat exchange enters the quenching and tempering tower through the second flue gas pipeline.

[0012] As a further implementation method, the flue gas generated by the roasting furnace enters the tempering tower through the first flue gas pipeline, and the flue gas generated by the roasting furnace and the calcining furnace is pretreated in the tempering tower. The pretreated flue gas enters the carbon powder adsorption reactor and the bag dust collector in sequence through the first flue gas pipeline for purification. The purified flue gas enters the first heat exchanger and exchanges heat with the high-temperature air of the first air exhaust pipeline, and then enters the catalytic reactor to remove nitrogen oxides in the flue gas. The flue gas from which nitrogen oxides have been removed enters the first condenser to exchange heat with condensed water for cooling. The cooled flue gas enters the desulfurization tower to remove sulfides in the flue gas. The flue gas carbon monoxide catalytic bed that removes sulfides converts carbon monoxide in the flue gas into carbon dioxide. Then the flue gas enters the wet electrostatic precipitator to remove suspended particulate matter in the flue gas.

[0013] As a further implementation method, the heat generated by the roasting furnace heats the air in the first air exhaust pipeline. Under the action of the first fan, the hot air enters the first heat exchanger through the first air exhaust pipeline to exchange heat with the flue gas to be catalytically reacted, thereby providing temperature conditions for the catalytic reduction reaction of nitrogen oxides in the flue gas. The cooled air after heat exchange enters the air compressor for pressurization treatment. The temperature of the pressurized air increases and is distributed to the carbon monoxide catalyst bed through the second air exhaust pipeline, thereby providing the necessary oxygen and heat energy for the catalytic oxidation reaction of carbon monoxide.

[0014] As a further implementation method, the condensed water undergoes a phase change after heat exchange with the flue gas in the first condenser. The condensed water after the phase change is transported to the carbon monoxide catalyst bed through the second steam pipeline under the action of the steam pump, providing temperature conditions for the catalytic oxidation reaction of carbon monoxide.

[0015] As a further implementation method, the heat transfer oil is stored in an oil storage tank, and a gear pump is used to transport the heat transfer oil to an oil pipeline. The heat transfer oil passes through an expansion tank and a filter in sequence through the oil pipeline and then enters a second heat exchanger. After heat exchange with the high-temperature flue gas of the calcining furnace in the second heat exchanger, the oil temperature rises, and finally the high-temperature heat transfer oil flows into the kneading pot.

[0016] As a further implementation method, a connecting pipeline is provided between the expansion tank and the kneading pot. On the one hand, the connecting pipeline allows the heat transfer oil to flow back from the kneading pot to the expansion tank after completing the heat energy transfer, and on the other hand, it provides necessary buffer space for the volume expansion of the heat transfer oil to relieve system pressure.

[0017] As a further implementation, it also includes a carbon powder silo, which is connected to the carbon powder adsorption reactor. Under the action of the fourth Roots blower, the carbon powder is transported from the carbon powder silo to the carbon powder adsorption reactor.

[0018] As a further implementation, it also includes a powder recovery bin, which is connected to the bag filter through a dust discharge pipe.

[0019] The second aspect of the present invention provides an operation method of a prebaked anode carbon capture system for industrial electrolytic aluminum, based on the prebaked anode carbon capture system for industrial electrolytic aluminum described in the first aspect of the present invention, comprising the following steps:

[0020] The DC power generated by the conversion of hot steam energy in S1, photovoltaic panels and steam turbines is converted into AC power through an inverter, and then the current and voltage of the AC power are precisely adjusted through a transformer and distributed to each power consumption end through cables;

[0021] S2. The flue gas generated by the burning furnace and the calcining furnace is subjected to multi-stage treatment to obtain high-purity carbon dioxide to provide raw materials for the carbon capture device. The heat generated by the roasting furnace is recycled and utilized in multiple stages to provide reaction conditions for the multi-stage treatment of flue gas. The heat generated by the calcining furnace is used to heat the waste heat boiler to generate steam to drive the steam turbine for power generation, and is used to heat the heat transfer oil to the required temperature on the other hand.

[0022] S3, close the air inlet valve, the second exhaust valve and the third exhaust valve, open the fifteenth regulating valve and the first exhaust valve, and introduce high-purity carbon dioxide into the absorption tower. In the absorption tower, the flue gas reacts chemically with the absorbent to capture carbon dioxide, and the treated flue gas is discharged through the first exhaust pipeline to achieve the operation of the normal temperature absorption stage;

[0023] S4, closing the fifteenth regulating valve, the first exhaust valve, the third exhaust valve and the air inlet valve, opening the second exhaust valve, starting the vacuum pump to extract gas from the absorption tower, and discharging it to the external environment through the second exhaust pipeline;

[0024] S5. Close the second exhaust valve, and open the third exhaust valve and the air inlet valve. The high-temperature steam generated by the motor boiler is injected into the absorption tower with the assistance of the third fan. After a certain period of purging, the hot steam and carbon dioxide mixed gas is guided to the second condenser for cooling and separation. The cooled carbon dioxide gas is compressed by the compressor and finally stored in the carbon storage tank.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The prebaked anode carbon capture system for industrial electrolytic aluminum of the present invention is coupled with photovoltaic-turbine combined power generation technology, and efficiently converts solar energy into electrical energy through photovoltaic panels. At the same time, the steam turbine generator set fully utilizes the heat generated in the carbon capture system, drives the steam turbine through high-temperature and high-pressure steam, converts thermal energy into mechanical energy, and then realizes the conversion of mechanical energy into electrical energy. In addition, the system optimizes the cascade utilization of energy, significantly reduces carbon emissions, and significantly improves energy utilization efficiency by adopting flue gas waste heat recovery technology, thereby providing a sustainable and efficient power supply for the entire system, effectively reducing the comprehensive energy consumption ratio of the carbon capture system, and promoting the development of low-carbon and environmentally friendly energy.

[0027] 2. The prebaked anode carbon capture system for industrial electrolytic aluminum of the present invention combines a carbon powder adsorption reactor with a bag filter, which greatly removes stubborn organic pollutants such as polycyclic aromatic hydrocarbons (PAHs), asphaltene, tar, benzo[a]pyrene (BaP) and volatile organic compounds (VOCs) in flue gas; through the selective catalytic reduction (SCR) process, nitrogen oxides (NO x ); In the desulfurization process, this system uses limestone gypsum wet desulfurization (FGD) technology to remove sulfur dioxide and other sulfides in flue gas; in order to further increase the concentration of carbon dioxide in flue gas, this system also uses the technology of catalytic oxidation of carbon monoxide to carbon dioxide, providing favorable conditions for the subsequent carbon capture step. Through a series of gas treatment and separation technologies, this system achieves deep purification of pollutants in flue gas, and significantly improves the separation efficiency and purity of carbon dioxide (CO2), and enhances the recovery rate of CO2.

[0028] 3. The prebaked anode carbon capture system for industrial electrolytic aluminum of the present invention adopts steam-assisted vacuum temperature swing cycle absorption technology in the absorbent regeneration step. By introducing steam, the gas phase driving force in the absorption tower and the mass transfer rate of the adsorbent are effectively enhanced, thereby improving the adsorption efficiency. At the same time, the system achieves efficient switching between adsorption and desorption through temperature swing, so that the adsorbent can be recycled, reducing the consumption and replacement frequency of the adsorbent. In addition, the system can further optimize the absorbent regeneration performance by regulating the operating parameters in the absorption tower, including gas pressure, temperature and flow, thereby improving the overall energy efficiency ratio and operational sustainability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] 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.

[0030] Figure 1 It is a schematic structural diagram of the prebaked anode carbon capture system for industrial electrolytic aluminum of the present invention.

[0031] Among them, 101, photovoltaic panel; 102, steam turbine; 103, inverter; 104, transformer; 201, roasting furnace; 202, quenching and tempering tower; 203, carbon powder adsorption reactor; 204, bag filter; 205, first heat exchanger; 206, catalytic reactor; 207, first condenser; 208, desulfurization tower; 209, CO catalytic bed; 210, wet electrostatic precipitator; 211, carbon powder silo; 212, recovery powder silo; 213, air compressor; 214, oil storage tank; 215, expansion tank; 216, filter; 217, second heat exchanger; 218, kneading pot; 219, calcining furnace; 220, residual Heat boiler; 301, absorption tower; 302, motor boiler; 303, second condenser; 304, compressor; 305, carbon storage tank; 4, first flue gas pipeline; 401, first regulating valve; 402, first Roots blower; 403, second regulating valve; 404, third regulating valve; 5, second flue gas pipeline; 501, fourth regulating valve; 502, second Roots blower; 503, sixteenth regulating valve; 6, third flue gas pipeline; 601, fifth regulating valve; 602, third Roots blower; 603, seventeenth regulating valve; 7, first steam pipeline; 701, sixth regulating valve; 8, oil pipeline; 801, first stop valve; 80 2. Gear pump; 803. Second stop valve; 804. Hot oil circulation pump; 805. Seventh regulating valve; 806. Eighth regulating valve; 9. Carbon powder conveying pipeline; 901. Fourth Roots blower; 902. Frequency conversion regulating valve; 10. Ash unloading pipeline; 105. Pulse valve; 11. First air exhaust pipeline; 111. Third stop valve; 112. First blower; 113. Fourth stop valve; 12. Smoke exhaust pipeline; 121. Ninth regulating valve; 122. Tenth regulating valve; 123. Eleventh regulating valve; 124. Twelfth regulating valve; 125. Thirteenth regulating valve; 126. Fourteenth regulating valve; 127. Fifteenth regulating valve Valve; 128, second fan; 13, second air exhaust pipeline; 131, fifth stop valve; 14, second steam pipeline; 141, sixth stop valve; 142, steam pump; 15, first exhaust pipeline; 151, first exhaust valve; 16, second exhaust pipeline; 161, second exhaust valve; 162, vacuum pump; 17, air supply pipeline; 171, air intake valve; 172, third fan; 18, mixed gas exhaust pipeline; 181, third exhaust valve; 182, seventh stop valve; 183, eighth stop valve; 19, first cable; 20, second cable; 21, third cable; 22, first main cable; 23 second main cable. DETAILED DESCRIPTION

[0032] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0033] It should be noted that the following detailed descriptions are all illustrative and 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.

[0034] In the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.

[0035] Embodiment 1

[0036] like Figure 1 As shown, this embodiment provides a prebaked anode carbon capture system for industrial electrolytic aluminum, comprising:

[0037] It comprises a combined power generation device, which is respectively connected to the flue gas treatment device and the carbon capture device to supply power to the electrical equipment of the flue gas treatment device and the carbon capture device.

[0038] The flue gas treatment device includes a roasting furnace 201 and a calcining furnace 219. The flue gases generated by the roasting furnace 201 and the calcining furnace 219 are subjected to multi-stage treatment to provide raw materials for the carbon capture device. The heat generated by the roasting furnace 201 is recycled and utilized at multiple stages to provide reaction conditions for the flue gas treatment process. The heat generated by the calcining furnace 219 is used to heat the waste heat boiler 220 to generate steam to drive the steam turbine 102 to generate electricity, and is used to heat the heat transfer oil to the required temperature on the one hand.

[0039] The carbon capture device includes an absorption tower 301 and a motor boiler 302 . The absorption tower 301 receives the flue gas that has undergone multi-stage treatment and completes carbon capture and adsorption with the assistance of high-temperature steam generated by the motor boiler 302 .

[0040] The combined power generation device is a photovoltaic-steam turbine combined power generation device, which includes a photovoltaic panel 101 , a steam turbine 102 , an inverter 103 and a transformer 104 .

[0041] The flue gas treatment device includes a roasting furnace 201, a tempering tower 202, a carbon powder adsorption reactor 203, a bag filter 204, a first heat exchanger 205, a catalytic reactor 206, a first condenser 207, a desulfurization tower 208, a CO catalytic bed 209, a wet electrostatic precipitator 210, a carbon powder silo 211, a recovery powder silo 212, an air compressor 213, an oil storage tank 214, an expansion tank 215, a filter 216, a second heat exchanger 217, a kneading pot 218, a calcining furnace 219 and a waste heat boiler 220.

[0042] The carbon capture device includes an absorption tower 301 , a motor boiler 302 , a second condenser 303 , a compressor 304 , and a carbon storage tank 305 .

[0043] The photovoltaic panel 101 terminal is connected to the inverter 103 via a first cable 19 , the inverter 103 is connected to the steam turbine 102 via a second cable 20 , and the inverter 103 is connected to the transformer 104 via a third cable 21 .

[0044] The transformer 104 is connected to the tempering tower 202, the carbon powder adsorption reactor 203, the bag filter 204, the first heat exchanger 205, the catalytic reactor 206, the first condenser 207, the desulfurization tower 208, the CO catalytic bed 209, the wet electrostatic precipitator 210, the air compressor 213, the first Roots blower 402, the second Roots blower 502, the third Roots blower 602, the gear pump 802, the hot oil circulation pump 804, the fourth Roots blower 901, the variable frequency regulating valve 902, the pulse valve 105, the first blower 112, and the steam pump 142 through the first main cable 22.

[0045] The transformer 104 is connected to the motor boiler 302, the second condenser 303, the compressor 304, the second fan 128, the vacuum pump 162, and the third fan 172 through the second main cable 23, and the transformer 104 supplies power to each electrical device through two main cables.

[0046] The roasting furnace 201, the tempering tower 202, the carbon powder adsorption reactor 203, and the bag dust collector 204 are connected through the first flue gas pipeline 4; a first regulating valve 401 and a first Roots blower 402 are arranged between the roasting furnace 201 and the tempering tower 202; a second regulating valve 403 is arranged between the tempering tower 202 and the carbon powder adsorption reactor 203; and a third regulating valve 404 is arranged between the carbon powder adsorption reactor 203 and the bag dust collector 204.

[0047] The carbon powder silo 211 is connected to the carbon powder adsorption reactor 203 via a carbon powder delivery pipeline 9 , and a fourth Roots blower 901 and a variable frequency regulating valve 902 are connected in series to the carbon powder delivery pipeline 9 .

[0048] The powder recovery bin 212 is connected to the bag filter 204 via an ash discharge pipeline 10 , and a pulse valve 105 is serially connected to the ash discharge pipeline 10 .

[0049] The roasting furnace 201 and the first heat exchanger 205 are connected via a first air exhaust pipeline 11 ; a third stop valve 111 and a first fan 112 are connected in series to the first air exhaust pipeline 11 .

[0050] The calcining furnace 219 is connected to the second heat exchanger 217 and the tempering tower 202 through the second flue gas pipeline 5; a fourth regulating valve 501 and a second Roots blower 502 are arranged between the calcining furnace 219 and the second heat exchanger 217; a sixteenth regulating valve 503 is arranged between the second heat exchanger 217 and the tempering tower 202.

[0051] The calcining furnace 219 is connected to the waste heat boiler 220 and the tempering tower 202 through the third flue gas pipeline 6; a fifth regulating valve 601 and a third Roots blower 602 are arranged between the calcining furnace 219 and the waste heat boiler 220; a seventeenth regulating valve 603 is arranged between the waste heat boiler 220 and the tempering tower 202.

[0052] The waste heat boiler 220 is connected to the steam turbine 102 via a first steam pipeline 7 ; a sixth regulating valve 701 is connected in series to the first steam pipeline 7 .

[0053] The oil storage tank 214 is connected to the expansion tank 215, the filter 216, the second heat exchanger 217, and the kneading pot 218 through an oil pipeline 8; a first stop valve 801 and a gear pump 802 are provided between the oil storage tank 214 and the expansion tank 215; a second stop valve 803 and a hot oil circulation pump 804 are provided between the expansion tank 215 and the filter 216; a seventh regulating valve 805 is provided between the filter 216 and the second heat exchanger 217; and an eighth regulating valve 806 is provided between the second heat exchanger 217 and the kneading pot 218.

[0054] The bag filter 204 is connected to the first heat exchanger 205, the catalytic reactor 206, the first condenser 207, the desulfurization tower 208, the CO catalytic bed 209, the wet electrostatic precipitator 210 and the absorption tower 301 through the flue gas exhaust pipeline 12; a ninth regulating valve 121 is arranged between the bag filter 204 and the first heat exchanger 205; and a tenth regulating valve 122 is arranged between the first heat exchanger 205 and the catalytic reactor 206.

[0055] An eleventh regulating valve 123 is provided between the catalytic reactor 206 and the first condenser 207; a twelfth regulating valve 124 is provided between the first condenser 207 and the desulfurization tower 208; a thirteenth regulating valve 125 is provided between the desulfurization tower 208 and the CO catalytic bed 209; a fourteenth regulating valve 126 is provided between the CO catalytic bed 209 and the wet electrostatic precipitator 210; a fifteenth regulating valve 127 and a second fan 128 are provided between the wet electrostatic precipitator 210 and the absorption tower 301;

[0056] The first heat exchanger 205 is connected to the air compressor 213 via a first air exhaust pipeline 11 ; a fourth stop valve 113 is provided between the first heat exchanger 205 and the air compressor 213 .

[0057] The air compressor 213 is connected to the CO catalytic bed 209 via a second air exhaust pipeline 13 ; a fifth stop valve 131 is serially connected to the second air exhaust pipeline 13 .

[0058] The first condenser 207 is connected to the CO catalytic bed 209 via a second steam pipeline 14 ; a sixth stop valve 141 and a steam pump 142 are serially connected to the second steam pipeline 14 .

[0059] The outlet of the absorption tower 301 is connected to the first exhaust pipeline 15; the first exhaust valve 151 is connected in series to the first exhaust pipeline 15; the vacuum pump 162 is connected to the absorption tower 301 through the second exhaust pipeline 16, and the second exhaust valve 161 is connected in series to the second exhaust pipeline 16; the motor boiler 302 is connected to the absorption tower 301 through the air supply pipeline 17; the air intake valve 171 and the third fan 172 are connected in series to the air supply pipeline 17.

[0060] The absorption tower 301 is connected to the second condenser 303, the compressor 304, and the carbon storage tank 305 through a mixed gas exhaust pipeline 18; a third exhaust valve 181 is provided between the absorption tower 301 and the second condenser 303; a seventh stop valve 182 is provided between the second condenser 303 and the compressor 304; and an eighth stop valve 183 is provided between the compressor 304 and the carbon storage tank 305.

[0061] The specific implementation process of this embodiment is as follows: in the photovoltaic-steam turbine combined power generation system, the DC power generated by the photovoltaic panel 101 and the power obtained by the hot steam energy conversion in the steam turbine 102 are respectively introduced into the DC-AC inverter 103 via the first cable 19 and the second cable 20. The inverter 103 is responsible for converting the input DC power into AC power, which is then transmitted to the transformer 104 via the third cable 21. In the transformer 104, the current and voltage are accurately adjusted and distributed to each power consumption end through the first main cable 22 and the second main cable 23, ensuring the power supply quality and stability of the power consumption equipment.

[0062] The temperature of the anode carbon blocks in the heating zone of the roasting furnace 201 reaches as high as 1180°C after air preheating and natural gas heating during the roasting process, and must be cooled before being taken out of the material box. The anode carbon blocks are cooled by using a blower to blow air, and the heat will heat the air blown into the cooling anode to about 600°C with a large flow rate. This part of the heat has a high utilization value, and it is necessary to take measures to recover the heat. The exhaust gas temperature of the roasting furnace 201 is between 80-160°C. The flue gas enters the first heat exchanger 205 after being pretreated by the tempering tower 202, the carbon powder adsorption reactor 203 and the bag filter 204. Since the catalytic reactor 206 needs to be carried out in the medium temperature range of 200-450°C, the roasting flue gas is heat exchanged with the high-temperature air to increase the flue gas temperature, thereby meeting the temperature requirements of the catalytic reactor 206.

[0063] The temperature of the flue gas from the calcining furnace 219 is about 1000°C, and this part of the heat also has a high utilization value. The present invention mainly utilizes the waste heat of the high-temperature calcining flue gas in two ways: one is to use the high-temperature flue gas to heat the waste heat boiler 220 to produce steam to drive the steam turbine for power generation; the other is to heat the high-temperature flue gas with the heat transfer oil, and heat the heat transfer oil below 200°C to about 200-300°C to heat the binder asphalt required for the kneading process and to heat and keep the kneading pot warm, etc. The cooled flue gas and the roasting flue gas are combined into the quenching and tempering tower 202 for treatment.

[0064] The roasting flue gas enters the tempering tower 202 through the first flue gas pipeline 4 from the first Roots blower 402; a part of the calcining flue gas enters the waste heat boiler 220 through the third flue gas pipeline 6 from the third Roots blower 602 for heat exchange, and then enters the tempering tower 202; the other part enters the second heat exchanger 217 through the second flue gas pipeline 5 from the second Roots blower 502 for heat exchange with the heat transfer oil, and then enters the tempering tower 202 for a series of flue gas purification treatment steps.

[0065] The oil storage tank 214 is the terminal storage tank of the thermal oil circulation system and is located at the lowest position of the system, so as to facilitate the use of gravity to assist the bottom suction operation and ensure the continuous supply of oil. The filter 216 is used in the system to filter impurities in the thermal oil and protect the cleanliness of the system. Considering the operating characteristics of the thermal oil under high temperature conditions, its dynamic viscosity is extremely sensitive to temperature changes. Therefore, during the transportation process, it is necessary to ensure the stability of fluid dynamics, maintain a constant flow rate and a suitable delivery pressure. To this end, the system adopts a high-efficiency gear pump 802, which provides sufficient delivery power and precise flow regulation. At the same time, its mechanical structure is simple and the maintenance cycle is long, which greatly improves the operational stability and operational reliability of the system. In addition, the hard tooth surface design of the gear pump 802 reduces wear and extends the service life of the equipment, thereby ensuring the efficient operation of the thermal oil circulation system while reducing the life cycle cost.

[0066] The expansion tank 215 occupies the highest point in the thermal oil circulation system, and its main function is to compensate for the volume expansion of the thermal oil when the temperature rises. In a closed system, if the expansion of the thermal oil volume cannot be effectively alleviated, the system pressure will rise sharply, which may cause equipment damage or safety risks. The access of the expansion tank 215 provides a key guarantee for the internal pressure balance of the system and effectively prevents potential hazards caused by excessive pressure. The core function of the expansion tank 215 is to provide the necessary buffer space for the volume expansion of the thermal oil. During the system heating process, the excess oil can flow smoothly into the expansion tank 215, thereby significantly reducing the pressure inside the system. Systems that lack sufficient expansion space may overflow due to the expansion of the oil volume, which not only wastes resources but also may cause environmental pollution. In addition, since the density of hot oil is lower than that of cold oil, the hot oil will naturally rise in the system. Setting the expansion tank 215 at the highest point of the system cleverly utilizes the thermal expansion and natural convection principles of the oil, so that the hot oil can flow more smoothly into the expansion tank 215 during the expansion process, thereby optimizing the thermal dynamic balance and overall performance of the system.

[0067] The gear pump 802 delivers the heat transfer oil in the oil storage tank 214 to the expansion tank 215 through the oil pipeline 8. The preheated heat transfer oil is further delivered to the filter 216 by the hot oil circulation pump 804 to perform deep purification of the oil to ensure that its impurity content is reduced to a minimum. The purified heat transfer oil then flows into the second heat exchanger 217, exchanges heat with the flue gas generated by high-temperature calcination, and absorbs heat to increase the oil temperature. The heated heat transfer oil flows into the kneading pot 218. During this process, the heat transfer oil not only provides the necessary heat for the kneading and molding operation, but also maintains the temperature of the kneading pot to ensure the uniformity and efficiency of the kneading process. After completing the heat energy transfer, the heat transfer oil flows back to the expansion tank 215, thereby completing a complete hot oil circulation process.

[0068] The roasting and calcining flue gas enters the tempering tower 202 for pretreatment. Through heat exchange, water condensation, dust interception and other processes, the flue gas is cooled, dehumidified and dusted, and the flue gas composition is made more uniform, which is conducive to the subsequent carbon powder adsorption treatment. The treated flue gas enters the first flue gas pipeline 4 from the tempering tower 202. Under the action of the first Roots blower 402, a negative pressure is formed in the pipeline, and the flue gas is collected and led to the carbon powder adsorption reactor 203. After fully contacting with the carbon powder, the carbon powder adsorbs asphalt smoke, tar, benzopyrene, VOCs and other organic pollutants in the flue gas, thereby achieving the purpose of purification. In this process, the fourth Roots blower 901 continuously transports carbon powder from the carbon powder silo 211 to the carbon powder adsorption reactor 203, while maintaining the adsorption efficiency, ensuring the continuous and stable operation of the entire system. The adsorbed flue gas enters the bag filter 204 for solid-gas separation. The bag filter contains baffles, ash hoppers and filter bags. First, the dust enters the ash hopper, and some coarser particles are intercepted by the baffles. Due to inertia, they fall into the ash hopper. Then, the flue gas passes through the filter bag, and the dust is intercepted on the surface of the filter bag. The purified gas enters the first heat exchanger 205 through the flue gas exhaust pipe 12. When the dust on the filter bag accumulates to a certain extent and the resistance increases, compressed air is sprayed into the filter bag through the pulse valve 105, causing the filter bag to expand, shake off the dust, and the dust falls into the ash hopper. The particles and dust in the ash hopper enter the powder recovery bin 212 through the ash unloading pipe 10, and the carbon powder is separated from other particles and dust by the separation equipment to provide raw materials for the molding of the anode carbon block.

[0069] The reaction temperature of the carbon monoxide catalytic bed 209 is between 200-300°C, which is relatively low. The cooled high-temperature air is compressed by the air compressor to meet the temperature requirement of the carbon monoxide catalytic bed 209. The flue gas from the catalytic reactor 206 has a relatively high temperature, and directly entering the desulfurization tower 208 will cause most of the heat loss. Therefore, a first condenser 207 is added between the catalytic reactor 206 and the desulfurization tower 208, and the flue gas transfers most of the heat to the condensed water. After the condensed water is gasified, this part of the heat is transferred to the carbon monoxide catalytic bed 209 through the steam pipe, thereby ensuring the reaction temperature of the catalytic bed. Through these heat exchange steps, efficient recovery and utilization of heat is achieved, thereby achieving the purpose of heat recovery.

[0070] Driven by the first fan 112, the high-temperature air is transported to the first heat exchanger 205 through the first air exhaust pipeline 11, where it exchanges heat with the flue gas from the bag filter 204 to achieve the air cooling process. The cooled air is then introduced into the air compressor 213 for pressurization and distributed to the CO catalytic bed 209 through the second air exhaust pipeline 13 to provide the necessary oxygen and heat energy for the catalytic oxidation reaction.

[0071] The heated flue gas enters the catalytic reactor 206. Under the action of the catalyst, the nitrogen oxides in the flue gas undergo a selective catalytic reduction (SCR) reaction to achieve efficient removal. The flue gas treated by SCR flows into the first condenser 207 and exchanges heat with the condensed water. The condensed water undergoes a phase change after absorbing heat. Under the action of the steam pump 142, the generated steam is transported to the CO catalytic bed 209 through the second steam pipeline 14 to maintain the temperature conditions required for the catalytic reaction. The flue gas cooled by the condenser is further guided to the desulfurization tower 208, and the lime-gypsum wet desulfurization technology is used to effectively remove the sulfides in the flue gas.

[0072] In the lime-gypsum wet flue gas desulfurization (FGD) system, the dominant chemical reaction in the desulfurization tower 208 is the immediate reaction of calcium oxide (CaO) and sulfur dioxide (SO2) to form calcium sulfite (CaSO3). Then, calcium sulfite is rapidly oxidized under the action of oxygen and converted into calcium sulfate (CaSO4). Although calcium oxide can also react with carbon dioxide (CO2) to form calcium carbonate (CaCO3), however, since sulfur dioxide is a strong reducing agent, its reaction kinetics with calcium oxide are significantly better than that of carbon dioxide. In addition, the stability of the generated calcium sulfite is extremely low and it is easy to further oxidize to calcium sulfate. Therefore, the absorption efficiency of carbon dioxide is relatively low during the desulfurization process. Carbon monoxide (CO) in flue gas usually does not react directly with calcium oxide due to its chemical inertness. Therefore, placing the catalytic oxidation process of carbon monoxide after the lime-gypsum desulfurization stage not only effectively reduces the occurrence of side reactions, but also improves the conversion rate of CO to CO2. After the above comprehensive treatment process, most of the pollutants in the flue gas have been effectively removed, but may still contain fine particles and residual pollutants. The application of wet electrostatic precipitator technology can deeply purify the flue gas and ensure the high efficiency of the subsequent carbon capture process. In addition, the wet electrostatic precipitator operation helps to reduce the flue gas temperature, providing an ideal operating temperature for the room temperature carbon capture absorption stage.

[0073] The flue gas treated by the desulfurization process is then introduced into the carbon monoxide catalytic oxidation bed 209. During this process, carbon monoxide is efficiently oxidized under the action of the catalyst and converted into carbon dioxide. After the catalytic oxidation step is completed, the flue gas is transported to the wet electrostatic precipitator 210 through a specific flue gas exhaust pipeline 12, and the suspended particulate matter and other pollutants in the flue gas are effectively separated and removed.

[0074] In the carbon capture device, the flue gas first undergoes a normal temperature absorption stage. During this process, the air intake valve 171, the second exhaust valve 161, and the third exhaust valve 181 are maintained in a closed state, and the fifteenth regulating valve 127 and the first exhaust valve 151 are activated at the same time to ensure that the flue gas is smoothly introduced into the absorption tower 301 through the flue gas exhaust pipeline 12. In the absorption tower 301, the flue gas reacts chemically with the absorbent to capture carbon dioxide. The treated flue gas is then discharged through the first exhaust pipeline 15, realizing the operation of the normal temperature absorption stage.

[0075] Next, the desorption stage of the absorption tower 301 is entered, which is divided into two sub-stages: vacuuming and steam purging. In the vacuuming sub-stage, the fifteenth regulating valve 127, the first exhaust valve 151, the third exhaust valve 181 and the air inlet valve 171 are closed, and the second exhaust valve 161 is opened, and the vacuum pump 162 is started to extract gas from the absorption tower 301 and discharge it to the external environment through the second exhaust pipeline 16.

[0076] In the steam purge sub-stage, the second exhaust valve 161 is closed, and the third exhaust valve 181 and the air inlet valve 171 are opened. In this stage, the high-temperature steam generated by the motor boiler 302 is injected into the absorption tower 301 with the assistance of the third fan 172. After a certain period of purge, the hot steam and carbon dioxide mixed gas are guided to the second condenser 303 for cooling and separation. The cooled carbon dioxide gas is compressed by the compressor 304 and finally stored in the carbon storage tank 305, thereby completing the overall process of the desorption stage.

[0077] Embodiment 2

[0078] This embodiment provides an operation method of a prebaked anode carbon capture system for industrial electrolytic aluminum, based on a prebaked anode carbon capture system for industrial electrolytic aluminum in Embodiment 1.

[0079] The DC power generated by the conversion of hot steam energy in S1, photovoltaic panels and steam turbines is converted into AC power through an inverter, and then the current and voltage of the AC power are precisely adjusted through a transformer and distributed to each power consumption end through cables;

[0080] S2. The flue gas generated by the burning furnace and the calcining furnace is subjected to multi-stage treatment to obtain high-purity carbon dioxide to provide raw materials for the carbon capture device. The heat generated by the roasting furnace is recycled and utilized in multiple stages to provide reaction conditions for the multi-stage treatment of flue gas. The heat generated by the calcining furnace is used to heat the waste heat boiler to generate steam to drive the steam turbine for power generation, and is used to heat the heat transfer oil to the required temperature on the other hand.

[0081] S3, close the air inlet valve, the second exhaust valve and the third exhaust valve, open the fifteenth regulating valve and the first exhaust valve, and introduce high-purity carbon dioxide into the absorption tower. In the absorption tower, the flue gas reacts chemically with the absorbent to capture carbon dioxide, and the treated flue gas is discharged through the first exhaust pipeline to achieve the operation of the normal temperature absorption stage;

[0082] S4, closing the fifteenth regulating valve, the first exhaust valve, the third exhaust valve and the air inlet valve, opening the second exhaust valve, starting the vacuum pump to extract gas from the absorption tower, and discharging it to the external environment through the second exhaust pipeline;

[0083] S5. Close the second exhaust valve, and open the third exhaust valve and the air inlet valve. The high-temperature steam generated by the motor boiler is injected into the absorption tower with the assistance of the third fan. After a certain period of purging, the hot steam and carbon dioxide mixed gas is guided to the second condenser for cooling and separation. The cooled carbon dioxide gas is compressed by the compressor and finally stored in the carbon storage tank.

[0084] 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.

[0085] 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 prebaked anode carbon capture system for industrial aluminum electrolysis, characterized in that: It includes a combined power generation device, which is connected to the flue gas treatment device and the carbon capture device respectively to supply power to the electrical equipment of the flue gas treatment device and the carbon capture device; The flue gas treatment device includes a roaster and a calciner. The flue gas generated by the roaster and the calciner is subjected to multi-stage treatment to provide raw materials for the carbon capture device. The heat generated by the roaster is recycled and utilized in multiple stages to provide reaction conditions for the flue gas treatment process. The heat generated by the calciner is used to heat the waste heat boiler to generate steam to drive the steam turbine for power generation, and is used to heat the heat transfer oil to the required temperature. The carbon capture device comprises an absorption tower and a motor boiler. The absorption tower receives the flue gas that has been processed in multiple stages and completes carbon capture and adsorption with the assistance of high-temperature steam generated by the motor boiler.

2. A prebaked anode carbon capture system for industrial aluminum electrolysis as claimed in claim 1, characterized in that: A part of the flue gas generated by the calcining furnace enters the waste heat boiler through the third flue gas pipeline for heat exchange, and the flue gas after heat exchange enters the quenching and tempering tower through the third flue gas pipeline, and the other part enters the second heat exchanger through the second flue gas pipeline for heat exchange with the heat transfer oil, and the flue gas after heat exchange enters the quenching and tempering tower through the second flue gas pipeline.

3. A prebaked anode carbon capture system for industrial aluminum electrolysis as claimed in claim 1, characterized in that: The flue gas generated by the roasting furnace enters the tempering tower through the first flue gas pipeline, and the flue gas generated by the roasting furnace and the calcining furnace is pretreated in the tempering tower. The pretreated flue gas enters the carbon powder adsorption reactor and the bag filter in sequence through the first flue gas pipeline for purification. The purified flue gas enters the first heat exchanger and exchanges heat with the high-temperature air of the first air exhaust pipeline, and then enters the catalytic reactor to remove nitrogen oxides in the flue gas. The flue gas from which the nitrogen oxides have been removed enters the first condenser to exchange heat with condensed water for cooling. The cooled flue gas enters the desulfurization tower to remove sulfides in the flue gas. The flue gas carbon monoxide catalytic bed from which sulfides are removed converts carbon monoxide in the flue gas into carbon dioxide. Then the flue gas enters the wet electrostatic precipitator to remove suspended particulate matter in the flue gas.

4. A prebaked anode carbon capture system for industrial aluminum electrolysis as claimed in claim 3, characterized in that: The heat generated by the roasting furnace heats the air in the first air exhaust pipeline. Under the action of the first fan, the hot air enters the first heat exchanger through the first air exhaust pipeline to exchange heat with the flue gas to be catalytically reacted, thereby providing temperature conditions for the catalytic reduction reaction of nitrogen oxides in the flue gas. The cooled air after the heat exchange enters the air compressor for pressurization. The temperature of the pressurized air increases and is distributed to the carbon monoxide catalyst bed through the second air exhaust pipeline, thereby providing necessary oxygen and heat energy for the catalytic oxidation reaction of carbon monoxide.

5. A prebaked anode carbon capture system for industrial aluminum electrolysis as claimed in claim 3, characterized in that: The condensed water undergoes a phase change after heat exchange with the flue gas in the first condenser. The condensed water after the phase change is transported to the carbon monoxide catalyst bed through the second steam pipeline under the action of the steam pump, providing temperature conditions for the catalytic oxidation reaction of carbon monoxide.

6. A prebaked anode carbon capture system for industrial aluminum electrolysis as claimed in claim 1, characterized in that: The heat transfer oil is stored in an oil storage tank, and a gear pump is used to transport the heat transfer oil to an oil pipeline. The heat transfer oil passes through an expansion tank and a filter in sequence through the oil pipeline and then enters a second heat exchanger. After heat exchange with the high-temperature flue gas of the calcining furnace in the second heat exchanger, the oil temperature rises, and finally the high-temperature heat transfer oil flows into the kneading pot.

7. A prebaked anode carbon capture system for industrial aluminum electrolysis as claimed in claim 1, characterized in that: A connecting pipeline is provided between the expansion tank and the kneading pot. The connecting pipeline allows the heat transfer oil to flow back from the kneading pot to the expansion tank after the heat energy transfer is completed, and provides necessary buffer space for the volume expansion of the heat transfer oil to relieve system pressure.

8. A prebaked anode carbon capture system for industrial aluminum electrolysis as claimed in claim 1, characterized in that: It also includes a carbon powder silo, which is connected to the carbon powder adsorption reactor. Under the action of the fourth Roots blower, the carbon powder is transported from the carbon powder silo to the carbon powder adsorption reactor.

9. A prebaked anode carbon capture system for industrial aluminum electrolysis as claimed in claim 1, characterized in that: It also includes a powder recovery bin, which is connected to the bag dust collector through a dust discharge pipeline.

10. An operating method of a prebaked anode carbon capture system for industrial aluminum electrolysis, characterized in that: A prebaked anode carbon capture system for industrial electrolytic aluminum according to any one of claims 1 to 9 comprises the following steps: The DC power generated by the conversion of hot steam energy in S1, photovoltaic panels and steam turbines is converted into AC power through an inverter, and then the current and voltage of the AC power are precisely adjusted through a transformer and distributed to each power consumption end through cables; S2. The flue gas generated by the burning furnace and the calcining furnace is subjected to multi-stage treatment to obtain high-purity carbon dioxide to provide raw materials for the carbon capture device. The heat generated by the roasting furnace is recycled and utilized in multiple stages to provide reaction conditions for the multi-stage treatment of flue gas. The heat generated by the calcining furnace is used to heat the waste heat boiler to generate steam to drive the steam turbine for power generation, and is used to heat the heat transfer oil to the required temperature on the other hand. S3, close the air inlet valve, the second exhaust valve and the third exhaust valve, open the fifteenth regulating valve and the first exhaust valve, and introduce high-purity carbon dioxide into the absorption tower. In the absorption tower, the flue gas reacts chemically with the absorbent to capture carbon dioxide, and the treated flue gas is discharged through the first exhaust pipeline to achieve the operation of the normal temperature absorption stage; S4, closing the fifteenth regulating valve, the first exhaust valve, the third exhaust valve and the air inlet valve, opening the second exhaust valve, starting the vacuum pump to extract gas from the absorption tower, and discharging it to the external environment through the second exhaust pipeline; S5. Close the second exhaust valve, and open the third exhaust valve and the air inlet valve. The high-temperature steam generated by the motor boiler is injected into the absorption tower with the assistance of the third fan. After a certain period of purging, the hot steam and carbon dioxide mixed gas is guided to the second condenser for cooling and separation. The cooled carbon dioxide gas is compressed by the compressor and finally stored in the carbon storage tank.

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