Flue gas primary carbon dioxide enrichment negative-pressure variable-temperature recovery device and use method thereof

Abstract

The invention provides a flue gas first-stage carbon dioxide enrichment negative-pressure variable-temperature recovery device and a use method thereof.The flue gas first-stage carbon dioxide enrichment negative-pressure variable-temperature recovery device comprises a fine dust removal device, the output end of the fine dust removal device is connected with a flue gas induced draft fan and a CO2 gas adsorption tower through pipelines, the output end of the flue gas induced draft fan is connected with a flue gas first-stage CO2 enrichment tower through a pipeline, and the output end of the flue gas first-stage CO2 enrichment tower is connected with a CO2 gas adsorption tower through a pipeline; the enriched CO2 gas buffer gas storage cabinet is connected to the output end of the flue gas primary CO2 enrichment tower through a pipeline, the output end of the enriched CO2 gas buffer gas storage cabinet is connected with an enriched CO2 gas pressurization cooling device and a flue gas dehydration device through pipelines, and the method comprises the following steps: S1, carbon dioxide enrichment; s2, cooling and dehydrating; s3, gas recovery; s4, cooling the adsorption tower; and S5, reverse blowing. According to the flue gas primary carbon dioxide enrichment negative-pressure variable-temperature recovery device provided by the invention, firstly, the flue gas of a nonferrous metallurgical furnace is subjected to fine dust removal, the dust content is reduced to 0.5 mg / Nm, the service life of a CO2 enrichment membrane is prolonged, and poisoning of an adsorbent in an adsorption tower can be effectively prevented.

Description

Technical Field

[0001] The present invention relates to the fields of non-ferrous metallurgy and gas separation, and in particular to a negative-pressure variable-temperature recovery device for primary carbon dioxide enrichment in flue gas and its usage method. Background Art

[0002] As the core energy-consuming equipment in the metallurgy industry, non-ferrous metallurgy furnaces have low energy efficiency, high energy consumption, and large carbon dioxide emissions, which are bottleneck problems restricting the realization of the "dual carbon" goal in the non-ferrous metallurgy industry. The carbon dioxide emissions in the non-ferrous metallurgy industry account for more than 6% of the total national emissions. Therefore, carbon emission reduction is the most realistic challenge faced by the metallurgy industry. The end-of-pipe negative-carbon technology for carbon dioxide capture and utilization is an effective way for the green and low-carbon development of China's metallurgy industry under the background of carbon neutrality.

[0003] However, different from iron and steel metallurgy, the non-ferrous metallurgy industry has problems such as coexistence of multiple components in flue gas, high content of harmful substances such as sulfur species, large fluctuations in gas temperature, and high water vapor content during the smelting process, resulting in low carbon dioxide capture efficiency, short equipment service life, and high energy consumption, causing insufficient resource utilization of carbon dioxide in metallurgy furnaces and a severe emission reduction situation.

[0004] Therefore, it is necessary to provide a negative-pressure variable-temperature recovery device for primary carbon dioxide enrichment in flue gas to solve the above technical problems. Summary of the Invention

[0005] The present invention provides a negative-pressure variable-temperature recovery device for primary carbon dioxide enrichment in flue gas, which solves the problems that the existing carbon dioxide capture technology cannot be applied to the carbon dioxide capture field of complex flue gas in non-ferrous metallurgy furnaces, and the existing technology has high energy consumption and low capture efficiency.

[0006] To solve the above technical problems, a negative-pressure variable-temperature recovery device for primary carbon dioxide enrichment in flue gas provided by the present invention includes: A fine dust removal device, the output end of the fine dust removal device is connected to a flue gas induced draft fan and a CO2 gas adsorption tower through pipelines, and the output end of the flue gas induced draft fan is connected to a primary flue gas CO2 enrichment tower through a pipeline; An enriched CO2 gas buffer gas storage tank, the enriched CO2 gas buffer gas storage tank is connected to the output end of the primary flue gas CO2 enrichment tower through a pipeline, and the output end of the enriched CO2 gas buffer gas storage tank is connected to an enriched CO2 gas pressurization and cooling device and a flue gas dehydration device through pipelines; The output end of the CO2 gas adsorption tower is respectively connected to a negative-pressure vacuum recovery CO2 device, an adsorption tower cooling device, a first solar heat transfer oil heating device, and a third solar heat transfer oil heating device through pipelines; A carbon dioxide gas storage tank, the carbon dioxide gas storage tank is connected to the output end of the negative-pressure vacuum recovery CO2 device through a pipeline; Rich CO2 gas pressurized reverse jetting device, the rich CO2 gas pressurized reverse jetting device is connected to the output end of the fine dust removal device through a pipeline; Second solar heat transfer oil heating device, the second solar heat transfer oil heating device 13a is connected to the output end of the flue gas dehydration device through a pipeline.

[0007] Preferably, the rich CO2 gas pressurized reverse jetting device is connected to the flue gas dehydration device through a pipeline.

[0008] Preferably, the adsorption tower cooling device is connected to the carbon dioxide gas storage tank through a pipeline.

[0009] Preferably, the enriched CO2 gas pressurized cooling device is connected to the rich CO2 gas pressurized reverse jetting device and the second solar heat transfer oil heating device through pipelines respectively.

[0010] Preferably, a disassembly component is arranged on one side of the flue gas induced draft fan, the disassembly component 15a includes a disassembly cover, and a first circular block and a second circular block are respectively connected to the surface of the disassembly cover and the surface of the flue gas induced draft fan.

[0011] Preferably, a bolt is arranged between the first circular block and the second circular block.

[0012] Preferably, a threaded sleeve is threadedly connected to the surface of the bolt.

[0013] Method for the flue gas primary carbon dioxide enrichment negative pressure variable temperature recovery device to recover primary carbon dioxide from flue gas, including the following steps: S1. After the flue gas CO2 passes through the fine dust removal device 1a, the flue gas is blown into the primary CO2 enrichment tower 3a by the flue gas induced draft fan 2a and enters the enriched CO2 gas buffer storage tank 4a for temporary storage. At this time, the exhausted gas formed by the flue gas primary CO2 enrichment tower 3a is discharged to the original flue gas system; S2. The CO2 flue gas enriched in S1 is first pressurized to 0.7 Mpa by the enriched CO2 gas pressurized cooling device 5a and cooled to 10 °C. The cold flue gas enters the flue gas dehydration device (6) to remove the condensed moisture in the flue gas. The dried flue gas enters the CO2 gas adsorption tower 7a for CO2 gas adsorption; The CO2 gas adsorption tower 7a is designed with three working states: one is the adsorption state, the second is the variable temperature negative pressure desorption state, and the third is the CO2 gas cooling tower body state. Therefore, three CO2 gas adsorption towers 7a are arranged in parallel; S3. The CO2 gas adsorbed in S2 is sucked out by the negative pressure vacuum CO2 recovery device 8a and pumped into the carbon dioxide gas storage tank 10a. The exhausted gas generated by the adsorption tower flows back to the inlet of the flue gas primary CO2 enrichment tower 3a for re-enrichment; S4. After desorbing CO2 under variable temperature, start the cooling device 9a of the adsorption tower at low temperature, use the low-temperature CO2 gas to cool the adsorption tower, and recycle the used low-temperature CO2 gas into the carbon dioxide gas storage tank 10a; S5. The rich CO2 gas pressurized reverse blowing device 12a of the fine dust removal device 1a described in S1 uses the gas pressurized by the enriched CO2 gas pressurizing and cooling device 5a to perform reverse blowing on the filter element.

[0014] Compared with the related technology, a flue gas primary carbon dioxide enrichment negative pressure variable temperature recovery device provided by the present invention has the following beneficial effects: The present invention provides a flue gas primary carbon dioxide enrichment negative pressure variable temperature recovery device. First, fine dust removal is performed on the flue gas of non-ferrous metallurgical furnaces, and the dust content is reduced to 0.5 mg / Nm³, which prolongs the service life of the CO2 enrichment membrane and can effectively prevent the adsorbent in the adsorption tower from poisoning.

[0015] The CO2 content in the flue gas is pre-enriched to 20%, which can greatly reduce the energy consumption of pressurizing and cooling the flue gas.

[0016] Use the solar heat transfer oil heating system to dry and evaporate the moisture of the flue gas dehydration device. The high water-absorbing resin particles can be reused, avoiding repeated filling of the water-absorbing resin and reducing the workload.

[0017] Use the solar heat transfer oil heating system to perform variable temperature desorption on the adsorption tower. Under the working condition of 200 °C of the heat transfer oil, the desorption efficiency of the adsorption tower is improved.

[0018] Using the solar heat transfer oil heating system reduces the energy consumption index of the entire device. Description of the Drawings

[0019] Figure 1 It is a schematic structural diagram of the first embodiment of a flue gas primary carbon dioxide enrichment negative pressure variable temperature recovery device provided by the present invention; Figure 2 It is a schematic structural diagram of the second embodiment of a flue gas primary carbon dioxide enrichment negative pressure variable temperature recovery device provided by the present invention; Figure 3 is Figure 2 the enlarged schematic diagram of part A shown in

[0020] Reference numerals in the figure: 1a, fine dust removal device; 2a, flue gas induced draft fan; 3a, first-stage flue gas CO2 enrichment tower; 4a, enriched CO2 gas buffer gas storage tank; 5a, enriched CO2 gas pressurization and cooling device; 6a, flue gas dehydration device; 7a, CO2 gas adsorption tower; 8a, negative pressure vacuum CO2 recovery device; 9a, adsorption tower cooling device; 10a, carbon dioxide gas storage tank; 11a, first solar heat transfer oil heating device; 12a, enriched CO2 gas pressurized reverse jet device; 13a, second solar heat transfer oil heating device; 14a, third solar heat transfer oil heating device; 15a, disassembly component; 151a, disassembly cover; 152a, first circular block; 153a, second circular block; 154a, bolt; 155a, threaded sleeve. Specific implementation mode

[0021] The present invention will be further described below in conjunction with the accompanying drawings and the implementation mode.

[0022] First embodiment Please refer to Figure 1 , wherein, Figure 1 is a schematic structural diagram of the first embodiment of a first-stage flue gas CO2 enrichment negative pressure variable temperature recovery device provided by the present invention. A first-stage flue gas CO2 enrichment negative pressure variable temperature recovery device includes: Fine dust removal device 1a, the output end of the fine dust removal device 1a is connected with a flue gas induced draft fan 2a and a CO2 gas adsorption tower 7a through pipelines, and the output end of the flue gas induced draft fan 2a is connected with a first-stage flue gas CO2 enrichment tower 3a through a pipeline; Enriched CO2 gas buffer gas storage tank 4a, the enriched CO2 gas buffer gas storage tank 4a is connected to the output end of the first-stage flue gas CO2 enrichment tower 3a through a pipeline, and the output end of the enriched CO2 gas buffer gas storage tank 4a is connected with an enriched CO2 gas pressurization and cooling device 5a and a flue gas dehydration device 6a through pipelines; The output end of the CO2 gas adsorption tower 7a is respectively connected with a negative pressure vacuum CO2 recovery device 8a, an adsorption tower cooling device 9a, a first solar heat transfer oil heating device 11a and a third solar heat transfer oil heating device 14a through pipelines; Carbon dioxide gas storage tank 10a, the carbon dioxide gas storage tank 10a is connected to the output end of the negative pressure vacuum CO2 recovery device 8a through a pipeline; Enriched CO2 gas pressurized reverse jet device 12a, the enriched CO2 gas pressurized reverse jet device 12a is connected to the output end of the fine dust removal device 1a through a pipeline; Second solar heat transfer oil heating device 13a, the second solar heat transfer oil heating device 13a is connected to the output end of the flue gas dehydration device 6a through a pipeline.

[0023] The CO₂-rich gas pressurized reverse jetting device 12a is connected to the flue gas dehydration device 6a through a pipeline.

[0024] The adsorption tower cooling device 9a is connected to the carbon dioxide gas storage tank 10a through a pipeline.

[0025] The CO₂-enriched gas pressurized cooling device 5a is respectively connected to the CO₂-rich gas pressurized reverse jetting device 12a and the second solar heat transfer oil heating device 13a through pipelines.

[0026] It is applicable to the complex flue gas conditions of non-ferrous metallurgical furnaces. The CO₂ content in the flue gas is generally about 5%, and it contains harmful substances such as F⁻, Cl⁻, and sulfides. After passing through the furnace dust removal system, the dust particles reach 10 mg / Nm³ for emission; after passing through the fine dust removal device 1a, the content of dust particles in the flue gas reaches 0.5 mg / Nm³, and then it is blown into the primary CO₂ enrichment tower 3a of the flue gas by the flue gas induced draft fan 2a and temporarily stored in the CO₂-enriched gas buffer gas storage tank 4a; the exhausted gas formed by the primary CO₂ enrichment tower 3a of the flue gas is discharged to the original flue gas system; the CO₂-enriched flue gas is first pressurized to 0.7 Mpa and cooled to 10 °C through the CO₂-enriched gas pressurized cooling device 5a; the cold flue gas enters the flue gas dehydration device (6) to remove the condensed water in the flue gas; the dry flue gas enters the CO₂ gas adsorption tower 7a for CO₂ gas adsorption; the CO₂ gas adsorption tower 7a is designed with three working states: one is the adsorption state, the second is the variable temperature negative pressure desorption state, and the third is the CO₂ gas cooling tower body state, so three CO₂ gas adsorption towers 7a are arranged in parallel; the adsorbed CO₂ gas is sucked out by the negative pressure vacuum CO₂ recovery device 8a and pumped into the carbon dioxide gas storage tank 10a; the exhausted gas generated by the adsorption tower flows back to the inlet of the primary CO₂ enrichment tower 3a of the flue gas for re-enrichment to improve the capture efficiency; after variable temperature desorption of CO₂, the low-temperature adsorption tower cooling device 9a is started, and the adsorption tower is cooled using low-temperature CO₂ gas, and the used low-temperature CO₂ gas is recovered into the carbon dioxide gas storage tank 10a.

[0027] The first solar heat transfer oil heating device 11a is responsible for providing the required high-temperature heat transfer oil for the negative pressure vacuum CO₂ recovery device 8a. Since the heat transfer oil does not undergo a phase change under the working temperature conditions, when using ordinary solar heat collection tubes, the working temperature of the heat transfer oil can be as high as 200 °C.

[0028] The CO₂-rich gas pressurized reverse jetting device 12a of the fine dust removal device 1a uses the gas pressurized by the CO₂-enriched gas pressurized cooling device 5a for reverse jetting of the filter element.

[0029] Specifically, in the preferred solution, the fine dust removal device 1a is arranged at the inlet position of the carbon dioxide negative pressure variable temperature recovery device, and the designed dust removal precision of the fine dust removal is less than 0.5 mg / Nm³ to meet the working requirements of the flue gas primary CO2 enrichment tower 3a and the CO2 gas adsorption tower 7a and prevent the enrichment membrane and the adsorbent from failing.

[0030] Compared with the related technologies, a flue gas primary carbon dioxide enrichment negative pressure variable temperature recovery device provided by the present invention has the following beneficial effects: The present invention provides a flue gas primary carbon dioxide enrichment negative pressure variable temperature recovery device. First, the flue gas of the non-ferrous metallurgical furnace is subjected to fine dust removal, and the dust content is reduced to 0.5 mg / Nm³, which prolongs the service life of the CO2 enrichment membrane and can effectively prevent the adsorbent in the adsorption tower from being poisoned.

[0031] The CO2 content in the flue gas is pre-enriched to 20%, which can greatly reduce the energy consumption of pressurizing and cooling the flue gas.

[0032] The solar heat transfer oil heating system is used to dry and evaporate the water of the flue gas dehydration device. The highly water-absorbent resin particles can be reused, avoiding the repeated filling of the water-absorbent resin and reducing the workload.

[0033] The solar heat transfer oil heating system is used to perform variable temperature desorption on the adsorption tower. Under the working condition of the heat transfer oil at 200 °C, the desorption efficiency of the adsorption tower is improved.

[0034] Using the solar heat transfer oil heating system reduces the energy consumption index of the entire device.

[0035] Second Embodiment Please refer to Figure 2 and Figure 3 Based on a flue gas primary carbon dioxide enrichment negative pressure variable temperature recovery device provided in the first embodiment of the present application, a second embodiment of the present application proposes another flue gas primary carbon dioxide enrichment negative pressure variable temperature recovery device. The second embodiment is only a preferred manner of the first embodiment, and the implementation of the second embodiment will not affect the independent implementation of the first embodiment.

[0036] Specifically, the difference of a flue gas primary carbon dioxide enrichment negative pressure variable temperature recovery device provided in the second embodiment of the present application is that a disassembly component 15a is arranged on one side of the flue gas induced draft fan 2a. The disassembly component 15a includes a disassembly cover 151a, and a first circular block 152a and a second circular block 153a are respectively connected to the surface of the disassembly cover 151a and the surface of the flue gas induced draft fan 2a.

[0037] A plurality of threaded holes adapted to the bolts 154a are provided between the first circular block 152a and the second circular block 153a. A circular connecting block is connected to one side of the disassembly cover 151a, facilitating the clamping connection of the disassembly cover 151a to one side of the flue gas induced draft fan 2a.

[0038] A bolt 154a is provided between the first circular block 152a and the second circular block 153a.

[0039] A threaded sleeve 155a is threadedly connected to the surface of the bolt 154a.

[0040] The working principle of a flue gas primary carbon dioxide enrichment negative pressure variable temperature recovery device provided by the present invention is as follows: During use, when cleaning the dust inside the flue gas induced draft fan 2a, first remove the threaded sleeve 155a on the surface of the bolt 154a. After the threaded sleeve 155a is removed, then remove the bolt 154a between the first circular block 152a and the second circular block 153a. After the bolt 154a is removed, then drive the first circular block 152a to separate from the flue gas induced draft fan 2a by pulling the disassembly cover 151a, and then the internal components of the flue gas induced draft fan 2a can be cleaned.

[0041] Compared with the related technology, a flue gas primary carbon dioxide enrichment negative pressure variable temperature recovery device provided by the present invention has the following beneficial effects: The present invention provides a flue gas primary carbon dioxide enrichment negative pressure variable temperature recovery device, and a disassembly component 15a is provided on one side of the flue gas induced draft fan 2a, facilitating the cleaning of internal dust after the housing is disassembled after the long-term use of the flue gas induced draft fan 2a.

[0042] In a further embodiment, a method for recovering primary carbon dioxide from flue gas by a flue gas primary carbon dioxide enrichment negative pressure variable temperature recovery device is disclosed, including the following steps: S1. After the flue gas CO2 passes through the fine dust removal device 1a, the flue gas induced draft fan 2a blows the flue gas into the primary CO2 enrichment tower 3a and enters the enriched CO2 gas buffer storage tank 4a for temporary storage. At this time, the waste gas formed by the primary CO2 enrichment tower 3a of the flue gas is discharged to the original flue gas system; S2. The CO2 flue gas enriched in S1 is first pressurized to 0.7 Mpa by the enriched CO2 gas pressurization and cooling device 5a and cooled to 10 °C. The cold flue gas enters the flue gas dehydration device (6) to remove the condensed water in the flue gas. The dried flue gas enters the CO2 gas adsorption tower 7a for CO2 gas adsorption; the CO2 gas adsorption tower 7a is designed with three working states: one is the adsorption state, the second is the variable temperature negative pressure desorption state, and the third is the CO2 gas cooling tower body state. Therefore, three CO2 gas adsorption towers 7a are arranged in parallel; The CO₂ gas adsorbed in S3 and S2 is sucked out by the negative-pressure vacuum CO₂ recovery device 8a and pumped into the CO₂ storage tank 10a. The exhausted gas generated by the adsorption tower flows back to the inlet of the flue gas primary CO₂ enrichment tower 3a for re-enrichment. S4. After desorbing CO₂ by changing the temperature, start the cooling device 9a of the adsorption tower at low temperature, use the low-temperature CO₂ gas to cool the adsorption tower, and recycle the used low-temperature CO₂ gas into the CO₂ storage tank 10a. S5. The pressurized reverse jet device 12a of the rich CO₂ gas of the fine dust removal device 1a described in S1 uses the gas pressurized by the enriched CO₂ gas pressurizing and cooling device 5a to perform reverse jetting on the filter element.

[0043] Compared with the related technology, a flue gas primary carbon dioxide enrichment negative pressure variable temperature recovery device and its use method provided by the present invention have the following beneficial effects: The present invention provides a flue gas primary carbon dioxide enrichment negative pressure variable temperature recovery device and its use method. The exhausted gas generated by its adsorption tower flows back to the inlet of the flue gas primary CO₂ enrichment tower 3a for re-enrichment, improving the capture efficiency. Secondly, the pressurized reverse jet device 12a of the rich CO₂ gas of the fine dust removal device 1a uses the gas pressurized by the enriched CO₂ gas pressurizing and cooling device 5a to perform reverse jetting on the filter element, achieving the cleaning effect of the element and extending the service life of the element.

[0044] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. All equivalent structural or equivalent process transformations made by using the description and drawings of the present invention, or directly or indirectly applied in other related technical fields, are similarly included in the patent protection scope of the present invention.

Claims

1. A flue gas primary carbon dioxide enrichment negative pressure temperature variable recovery device, characterized in that: include: A fine dust removal device, wherein the output end of the fine dust removal device is connected to a flue gas induced draft fan and a CO2 gas adsorption tower through a pipeline, and the output end of the flue gas induced draft fan is connected to a flue gas primary CO2 enrichment tower through a pipeline; An enriched CO2 gas buffer gas storage cabinet, wherein the enriched CO2 gas buffer gas storage cabinet is connected to the output end of the flue gas primary CO2 enrichment tower through a pipeline, and the output end of the enriched CO2 gas buffer gas storage cabinet is connected to an enriched CO2 gas pressurization cooling device and a flue gas dehydration device through a pipeline; The output end of the CO2 gas adsorption tower is respectively connected to a negative pressure vacuum CO2 recovery device, an adsorption tower cooling device, a first solar thermal oil heating device and a third solar thermal oil heating device through pipelines; A carbon dioxide gas storage cabinet, which is connected to the output end of the negative pressure vacuum CO2 recovery device through a pipeline; A CO2-rich gas pressurized reverse blowing device, wherein the CO2-rich gas pressurized reverse blowing device is connected to the output end of the fine dust removal device through a pipeline; The second solar thermal oil heating device 13a is connected to the output end of the flue gas dehydration device through a pipeline.

2. The flue gas primary carbon dioxide enrichment negative pressure temperature variable recovery device according to claim 1, characterized in that: The CO2-rich gas pressurized reverse blowing device is connected to the flue gas dehydration device through a pipeline.

3. The flue gas primary carbon dioxide enrichment negative pressure temperature variable recovery device according to claim 1, characterized in that: The adsorption tower cooling device is connected to the carbon dioxide gas storage cabinet through a pipeline.

4. The flue gas primary carbon dioxide enrichment negative pressure temperature variable recovery device according to claim 1, characterized in that: The enriched CO2 gas pressurized cooling device is connected to the enriched CO2 gas pressurized reverse blowing device and the second solar thermal oil heating device through pipelines.

5. The flue gas primary carbon dioxide enrichment negative pressure temperature variable recovery device according to claim 1, characterized in that: A disassembly assembly is disposed on one side of the flue gas induced draft fan. The disassembly assembly 15a comprises a disassembly cover. A first circular block and a second circular block are connected to a surface of the disassembly cover and a surface of the flue gas induced draft fan, respectively.

6. The flue gas primary carbon dioxide enrichment negative pressure temperature variable recovery device according to claim 5, characterized in that: Bolts are arranged between the first circular block and the second circular block.

7. The flue gas primary carbon dioxide enrichment negative pressure temperature variable recovery device according to claim 6, characterized in that: The surface of the bolt is threadedly connected with a threaded sleeve.

8. A method for recovering primary carbon dioxide from flue gas using the flue gas primary carbon dioxide enrichment negative pressure temperature variable recovery device according to any one of claims 1 to 7, characterized in that: The steps include: S1, after the flue gas CO2 passes through the fine dust removal device 1a, the flue gas induced draft fan 2a blows the flue gas into the primary CO2 enrichment tower 3a, and enters the enriched CO2 gas buffer storage cabinet 4a for temporary storage. At this time, the exhaust gas formed by the primary CO2 enrichment tower 3a is discharged to the original flue gas system; The CO2 flue gas enriched by S2 and S1 is first pressurized to 0.7Mpa and cooled to 10°C by the CO2 enriched gas pressurization cooling device 5a. The cold flue gas enters the flue gas dehydration device (6) to remove the condensed water in the flue gas. The dry flue gas enters the CO2 gas adsorption tower 7a for CO2 gas adsorption. The CO2 gas adsorption tower 7a is designed to have three working states: one is the adsorption state, the second is the variable temperature negative pressure desorption state, and the third is the CO2 gas cooling tower state. Therefore, three CO2 gas adsorption towers 7a are arranged in parallel. The CO2 gas adsorbed in S3 and S2 is sucked out by the negative pressure vacuum CO2 recovery device 8a and pumped into the carbon dioxide gas storage cabinet 10a. The exhaust gas produced by the adsorption tower flows back to the inlet of the flue gas primary CO2 enrichment tower 3a for re-enrichment; S4, after the temperature-variable desorption of CO2, the low-temperature adsorption tower cooling device 9a is turned on, and the low-temperature CO2 gas is used to cool the adsorption tower, and the used low-temperature CO2 gas is recovered into the carbon dioxide gas storage cabinet 10a; The CO2-rich gas pressurized back-blowing device 12a of the fine dust removal device 1a described in S5 and S1 uses the gas pressurized by the CO2-rich gas pressurized cooling device 5a to back-blow the filter element.

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