Modular carbon capture system and method for flue gas treatment in carbon industry

Abstract

The invention discloses a modularized carbon capture system and method for flue gas treatment in the carbon industry, and belongs to the technical field of carbon capture, and the modularized carbon capture system comprises a flue gas treatment module, a solid amine adsorption module and a membrane separation module which are connected in sequence. The flue gas treatment module is used for treating the flue gas, so that the flue gas meets the optimal adsorption state of the solid amine adsorption module, and the damage to the membrane separation module can be avoided while the damage of impurities to the performance of an adsorbent is avoided; cO2 in flue gas is efficiently captured through the solid amine adsorption module, so that the capturing efficiency of CO2 is improved; the solid amine adsorption module sends CO2 rich gas into the membrane separation module for high-purity separation and purification, the membrane assembly does not need high-pressure operation or multi-stage series connection for separation of the CO2 rich gas, energy consumption is low, the solid amine adsorption module exhausts purified flue gas in advance before the CO2 rich gas is sent into the membrane separation module, the membrane assembly is further prevented from being polluted, and the solid amine adsorption module does not need high-pressure operation or multi-stage series connection for separation of the CO2 rich gas. The separation efficiency and the service life of the membrane module are further ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon capture, and particularly relates to a modular carbon capture system and method for flue gas treatment in the carbon industry. Background Technique

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

[0003] In the carbon industry, during the heat treatment processes such as calcination and roasting of key carbon products such as graphite electrodes and carbon blocks, a large amount of high-temperature flue gas is generated. This flue gas has a complex composition, including various atmospheric pollutants such as CO2, pitch fume, tar, SO2, nitrogen oxides (NO x ) and particulate matter (PM); and the volume fraction of CO2 is relatively low, usually maintained in the range of 10% - 15%. When treating the above high-temperature flue gas, carbon capture technology is preferably used.

[0004] In the existing carbon capture technologies, the conventional solvent method has problems such as high energy consumption, relatively serious equipment corrosion, and amine escape; when using the physical adsorption method, although it shows high selectivity for CO2 capture, its application is limited in the scenario of low-concentration CO2 flue gas in the carbon industry, and the adsorbent is easily affected by moisture and impurities, thereby significantly reducing the capture efficiency; the membrane separation method can better handle low-concentration CO2, but in order to achieve a higher CO2 capture concentration, it is necessary to increase the separation pressure difference, resulting in a significant increase in operating energy consumption.

[0005] In order to increase the capture concentration of low-concentration CO2, the prior art discloses a carbon dioxide capture system based on the coupling of membrane separation method and adsorption method. The treated flue gas is first passed through the membrane separation method to increase the concentration of CO2, and then CO2 is collected through the adsorption method.

[0006] However, the above scheme has the following problems when applied to the flue gas in the carbon industry:

[0007] There are many impurities in the flue gas. Even after pretreatment, there are still a certain amount of impurities. When the flue gas directly contacts the membrane module, it is easy to cause surface pollution of the membrane module, resulting in a decrease in separation efficiency and a shortening of the membrane module life; at the same time, the membrane separation of low-concentration CO2 (10% - 15%) requires high-pressure operation or multi-stage series connection, with high energy consumption, and it cannot reduce the operating cost while increasing the capture concentration of low-concentration CO2. Summary of the Invention

[0008] In view of the above problems, the present invention provides a modular carbon capture system and method for flue gas treatment in the carbon industry, which sequentially arranges a flue gas treatment module, a solid amine adsorption module and a membrane separation module, and utilizes the flue gas treatment module to treat the flue gas so that the flue gas meets the optimal adsorption state of the solid amine adsorption module, thereby avoiding impurities from damaging the adsorbent performance of the solid amine adsorption module and also avoiding damage to the membrane separation module; then, CO2 is efficiently captured from the flue gas through two adsorption towers arranged in parallel in the solid amine adsorption module, thereby improving the CO2 capture efficiency; finally, the solid amine adsorption module sends the CO2 rich gas into the membrane separation module for high-purity separation and purification, and the membrane assembly does not require high-pressure operation or multi-stage series connection for separating the CO2 rich gas, and has low energy consumption; in addition, the solid amine adsorption module discharges the purified flue gas before sending the CO2 rich gas into the membrane separation module, thereby further avoiding contamination of the membrane assembly, thereby further ensuring the separation efficiency and life of the membrane assembly.

[0009] To achieve the above object, the present invention adopts the following technical solutions:

[0010] In a first aspect, a modular carbon capture system for flue gas treatment in the carbon industry is provided, comprising a flue gas treatment module, a solid amine adsorption module and a membrane separation module connected in sequence;

[0011] The flue gas treatment module includes a ridge-type demister, a first condenser, a second condenser, and an electric heater which are sequentially connected through a flue gas intake pipeline;

[0012] The solid amine adsorption module includes two identical adsorption towers connected in parallel, both of which are connected to the first vacuum pump and the CO2 gas storage tank through the first CO2 gas pipeline; the bottom air inlet of the adsorption tower is connected to the purge gas pipeline; a one-way valve is arranged on the purge gas pipeline; the top air outlet of the adsorption tower is connected to the CO2 gas storage tank through the second CO2 gas pipeline; the adsorption stage or regeneration stage of the two adsorption towers is carried out alternately;

[0013] The membrane separation module includes a compressor, a molecular sieve dryer, a coalescing filter, a membrane assembly, a second vacuum pump, a booster pump and a CO2 product gas storage tank which are connected in sequence; the CO2 product gas storage tank is connected to a purge gas pipeline.

[0014] Preferably, the electric heater adopts an electric heating wire or a PTC heating element to accurately heat the flue gas temperature to the optimal adsorption temperature range of the solid amine adsorption module; the flue gas inlet pipeline adopts a stainless steel pipe; a first pressure regulating valve is arranged on the main pipeline of the electric heater outlet to stabilize the intake pressure of the two adsorption towers during the adsorption stage.

[0015] Preferably, a first shut-off valve is provided at the inlet of the roof-type demister; a regulating valve is provided between every two adjacent devices among the roof-type demister, the first condenser, the second condenser, and the electric heater; both the regulating valve and the first shut-off valve are electrically controlled valves, and both the electric heater and the electrically controlled valves are connected to the first PLC controller of the flue gas treatment module.

[0016] Preferably, the adsorption tower further includes a top air inlet, a bottom air outlet, and a side air outlet. The top air inlet is connected to the intake branch pipe of the main pipe at the outlet of the electric heater, and an electrically controlled intake valve is provided on the intake branch pipe. Corresponding electrically controlled valves are provided at both the bottom air inlet and the top air outlet.

[0017] Preferably, the bottom air outlets of the two adsorption towers are both connected to the flue gas exhaust pipe, and an exhaust valve is provided on the flue gas exhaust pipe; the side air outlets of the two adsorption towers are both connected to the first vacuum pump, and an inlet valve is provided between the adsorption tower and the first vacuum pump; the first vacuum pump is connected to the CO2 storage tank, and a first outlet valve is provided between the first vacuum pump and the CO2 storage tank; the internal pipes of the solid amine adsorption module are made of carbon steel with a Teflon lining.

[0018] Preferably, the solid amine adsorption module further includes a programmed control valve group, which is connected to all the valves of the solid amine adsorption module and is also connected to the first vacuum pump; the programmed control valve group is connected to the second PLC controller of the solid amine adsorption module.

[0019] Preferably, the inlet of the compressor is connected to the outlet of the CO2 storage tank through the CO2 rich gas exhaust pipe; a shut-off valve is provided between every two adjacent devices among the CO2 storage tank, the compressor, the molecular sieve dryer, and the coalescing filter; a shut-off valve is provided between the second vacuum pump and the booster pump.

[0020] Preferably, a pressure regulating valve is provided at both the inlet and the permeate side of the membrane module; the retentate side of the membrane module is connected to the tail gas outlet pipe; a shut-off valve is provided on the tail gas outlet pipe; the internal pipes of the membrane separation module are made of carbon steel.

[0021] In a second aspect, a capture method for the modular carbon capture system for flue gas treatment in the carbon industry as described above is provided, and the specific steps are as follows:

[0022] The flue gas that has undergone preliminary denitrification, desulfurization, and dust removal pretreatment enters the roof-type demister to remove larger-sized fog droplets and liquid water in the flue gas; then it sequentially enters the first condenser and the second condenser for deep cooling, drying, and dehydration; finally, it enters the electric heater to be heated to the optimal adsorption temperature of the solid amine adsorption module.

[0023] The treated flue gas enters one of the two adsorption towers to adsorb CO2. After the flue gas after adsorption is discharged from the current adsorption tower, the current adsorption tower enters the regeneration stage of the catalyst, and the adsorbed CO2 is sent to the CO2 storage tank for storage; at the same time, the treated flue gas enters the other adsorption tower among the two adsorption towers to adsorb CO2; the adsorption stage or regeneration stage of the two adsorption towers is carried out alternately;

[0024] The CO2 stored in the CO2 storage tank is compressed and heated by a compressor, and then sent to a molecular sieve dryer to further remove the trace moisture in the CO2-rich gas; then sent to a coalescing filter to remove the oil mist and particulate matter in the CO2-rich gas; and then sent to a membrane module for membrane separation and purification; finally sent to the CO2 product storage tank for storage.

[0025] Preferably, during the adsorption and regeneration process, after desorption regeneration, a small amount of CO2 product gas is introduced into the bottom of the adsorption tower for purging; the CO2 product gas uses the product gas from the CO2 product storage tank.

[0026] Compared with the prior art, the advantages and positive effects of the present invention are:

[0027] In the present invention, by sequentially arranging a flue gas treatment module, a solid amine adsorption module, and a membrane separation module, the flue gas is treated by the flue gas treatment module to make the flue gas meet the optimal adsorption state of the solid amine adsorption module, while avoiding damage to the adsorbent performance of the solid amine adsorption module by impurities and also avoiding damage to the membrane separation module; then, the two adsorption towers arranged in parallel in the solid amine adsorption module are used to efficiently capture CO2 from the flue gas, improving the CO2 capture efficiency; finally, the solid amine adsorption module sends the CO2-rich gas to the membrane separation module for high-purity separation and purification. The separation of the CO2-rich gas by the membrane module does not require high-pressure operation or multi-stage series connection, with low energy consumption. Moreover, before the solid amine adsorption module sends the CO2-rich gas to the membrane separation module, the purified flue gas is discharged first, further avoiding pollution of the membrane module and ensuring the separation efficiency and service life of the membrane module. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The specification drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0029] Figure 1 is the overall structural schematic diagram of the modular carbon capture system of Embodiment 1 or 2 of the present invention;

[0030] Figure 2 is the structural schematic diagram of the flue gas treatment module of Embodiment 1 or 2 of the present invention;

[0031] Figure 3It is a schematic structural diagram of the solid amine adsorption module of Embodiment 1 or 2 of the present invention;

[0032] Figure 4 It is a schematic structural diagram of the membrane separation module of Embodiment 1 or 2 of the present invention;

[0033] In the figure:

[0034] 1. Flue gas treatment module; 2. Solid amine adsorption module; 3. Membrane separation module; 101. Roof type demister; 102. First condenser; 102a. First electric control valve; 102b. First temperature sensor; 102c. Second temperature sensor; 103. Second condenser; 103a. Second electric control valve; 103b. Third temperature sensor; 103c. Fourth temperature sensor; 104. Electric heater; 105. First stop valve; 106. First regulating valve; 107. Second regulating valve; 108. Third regulating valve; 109. Flue gas inlet pipeline; 110. First cooling water inlet pipeline; 111. First cooling water drainage pipeline; 112. Second cooling water inlet pipeline; 113. Second cooling water drainage pipeline; 201A. First adsorption tower; 201B. Second adsorption tower; 202. First vacuum pump; 203. CO2 gas storage tank; 204. Program control valve group; 205. First pressure regulating valve; 206. First exhaust valve; 207. Second exhaust valve; 208. First inlet valve; 209. Second inlet valve; 210. First outlet valve; 211. Check valve; 212a. First electric control intake valve; 212b. Second electric control intake valve; 213. First flue gas exhaust pipeline; 214. Second flue gas exhaust pipeline; 215. First CO2 gas transmission pipeline; 216. Purge gas pipeline; 217. Second CO2 gas transmission pipeline; 301. Compressor; 302. Molecular sieve dryer; 303. Coalescing filter; 304. Membrane module; 305. Second vacuum pump; 306. CO2 product gas storage tank; 307. Second stop valve; 308. Third stop valve; 309. Fourth stop valve; 310. Second pressure regulating valve; 311. Third pressure regulating valve; 312. Fifth stop valve; 313. Sixth stop valve; 314. CO2 rich gas exhaust pipeline; 315. Tail gas outlet pipeline; 316. CO2 product outlet pipeline; 317. Booster pump. Detailed implementation mode

[0035] It should be noted that the following detailed description is exemplary and is intended to provide further illustration of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0036] The following combines the drawings to describe the present invention in detail. A modular carbon capture system for flue gas treatment in the carbon industry disclosed in this embodiment is as Figure 1As shown in the figure, it includes a flue gas treatment module 1, a solid amine adsorption module 2, and a membrane separation module 3; among them, the solid amine adsorption module 2 is respectively connected to the flue gas treatment module 1 and the membrane separation module 3.

[0037] The flue gas treatment module 1, the solid amine adsorption module 2, and the membrane separation module 3 are all provided with PLC controllers for their respective modules. The central control room is provided with a distributed control system (DCS system), which communicates with the PLC controllers of each module through industrial Ethernet (Profinet protocol) to realize centralized monitoring, operation management, data analysis, and fault diagnosis tasks for the entire carbon capture system; the DCS system real-time displays the operating parameters of each module, such as pressure, temperature, flow rate, pressure difference, valve status, etc., to facilitate operators for remote monitoring and operation.

[0038] The main function of the flue gas treatment module 1 is to further refine and pre-treat the flue gas to meet the inlet gas requirements of the subsequent solid amine adsorption module 2. The solid amine adsorption module 2 treats the flue gas and captures CO2, and the captured CO2 is sent to the membrane separation module 3 for further compression and collection.

[0039] Specifically, as Figure 2 shown, the flue gas treatment module 1 includes a flue gas inlet pipeline 109. A roof-type demister 101 is arranged on the flue gas inlet pipeline 109. The outlet of the roof-type demister 101 is connected to a first condenser 102 through the flue gas inlet pipeline 109. The outlet of the first condenser 102 is connected to a second condenser 103 through the flue gas inlet pipeline 109. The outlet of the second condenser 103 is connected to an electric heater 104 through the flue gas inlet pipeline 109.

[0040] The flue gas from the carbon production line after preliminary denitrification, desulfurization, and dust removal pretreatment enters the flue gas treatment module 1 through the flue gas inlet pipeline 109. The flue gas first enters the roof-type demister 101, and by using the collision and gravity sedimentation of the roof blades, it efficiently removes larger-sized droplets and liquid water in the flue gas, as well as particulate impurities, ensuring that the droplet concentration in the outlet flue gas is lower than 75mg / m 3 , creating favorable conditions for the subsequent condensation and drying process.

[0041] The flue gas preliminarily treated by the roof-type demister 101 then sequentially enters the first condenser 102 and the second condenser 103. In this embodiment, both of these two-stage condensers adopt efficient shell-and-tube heat exchangers or plate heat exchangers, and use cooling water or chilled water as the cooling medium to deeply cool and dehydrate the flue gas.

[0042] The first condenser 102 mainly reduces the flue gas temperature from the inlet temperature to about 20°C and removes most of the water vapor in the flue gas. The second condenser 103 further reduces the flue gas temperature to about 10°C, ensures that the flue gas dew point is lower than 5°C, maximally removes the residual moisture in the flue gas, and prevents the influence of moisture on the performance of the subsequent solid amine adsorbent. The flue gas after deep condensation and drying finally enters the electric heater 104 for heating.

[0043] As Figure 2 shown, the first condenser 102 includes a first medium side and a first heat exchange side. One end of the first medium side is connected to the roof-type demister 101, and the other end is connected to the second condenser 103; one end of the first heat exchange side is connected to the first cooling water inlet pipeline 110, and the other end is connected to the first cooling water drainage pipeline 111; a first temperature sensor 102b is arranged between the first medium side and the roof-type demister 101, a second temperature sensor 102c is arranged between the first medium side and the second condenser 103, and a first electric control valve 102a is arranged on the first cooling water inlet pipeline 110.

[0044] As Figure 2 shown, the second condenser 103 includes a second medium side and a second heat exchange side. One end of the second medium side is connected to the first condenser, and the other end is connected to the electric heater 104; one end of the second heat exchange side is connected to the second cooling water inlet pipeline 112, and the other end is connected to the second cooling water drainage pipeline 113; a third temperature sensor 103b is arranged between the second medium side and the second condenser 103, a fourth temperature sensor 103c is arranged between the second medium side and the electric heater 104; a second electric control valve 103a is arranged on the second cooling water inlet pipeline 112.

[0045] Electric control valves are respectively arranged on the cooling water inlet pipelines of the first condenser and the second condenser to regulate the cooling water flow rates of the first condenser and the second condenser. Temperature sensors are installed at the inlets and outlets of the medium sides of the first condenser or the second condenser to collect the temperature of the flue gas in real time.

[0046] In this embodiment, the electric heater uses an electric heating wire or a PTC heating element to precisely heat the flue gas temperature to 80 - 100°C to match the optimal adsorption temperature of the solid amine adsorption module 2. Corrosion-resistant 316L stainless steel pipes are used to connect the devices inside the flue gas treatment module 1 to ensure the long-term stable operation of the system in a wet flue gas environment.

[0047] It can be understood that, aiming at the complex characteristics of high humidity and various impurity types in the carbonaceous flue gas, through the treatment process of the demister, condenser, and electric heater, the moisture, droplets, particulate matter, and gaseous impurities in the flue gas can be effectively removed, ensuring that the flue gas entering the solid amine adsorption module meets strict process standards; while avoiding the damage of impurities to the performance of the adsorbent, it can also avoid damaging the membrane separation module 3, guaranteeing the long-term stable and efficient operation of the entire carbon capture system.

[0048] Furthermore, a first stop valve 105 is provided at the inlet of the chevron demister 101 to control the on-off of the flue gas inlet pipeline 109, facilitating the maintenance of subsequent equipment; a first regulating valve 106 is provided between the chevron demister 101 and the first condenser 102; a second regulating valve 107 is provided between the first condenser 102 and the second condenser 103; a third regulating valve 108 is provided between the second condenser 103 and the electric heater 104 to adjust the flue gas flow rate and control process parameters (such as temperature and pressure).

[0049] In this embodiment, between the flue gas treatment module 1 and the solid amine adsorption module 2, a 316L stainless steel pipeline is used for connection, and the interface parameters are temperature 80 - 100 °C, pressure 0.5 - 1.0 Mpa, and the sulfur content in the flue gas ≤ 50 ppm.

[0050] It should be noted that all the regulating valves (the first regulating valve, the second regulating valve, the third regulating valve, the first electric regulating valve, the second electric regulating valve) and the first stop valve in the above flue gas treatment module 1 adopt electric control valves, and the electric heater 104 and the electric control valves are all connected to the first PLC controller of the flue gas treatment module 1. At the same time, all the temperature sensors (the first temperature sensor, the second temperature sensor, the third temperature sensor, the fourth temperature sensor) in the above flue gas treatment module 1 are also connected to the first PLC controller to transmit temperature information to the first PLC controller.

[0051] The first PLC controller automatically adjusts the working states of each device (the electric heater 104, the first condenser, the second condenser) and the opening degrees of each valve according to the preset logic.

[0052] For example: according to the outlet temperature signal of the electric heater 104, adjust the heating power of the electric heater, or adjust the opening degree of the third regulating valve 108 to adjust the flue gas flow rate entering the electric heater.

[0053] Alternatively, the first PLC controller automatically adjusts the opening degree of the corresponding electric control valve according to the temperature difference ΔT1 between the inlet and outlet flue gases on the first medium side or the temperature difference ΔT2 between the inlet and outlet on the second medium side. For example, when ΔT1 or ΔT2 is less than the set value, it indicates insufficient cooling effect. The first PLC controller outputs a signal to control the corresponding electric control valve to increase the opening degree and increase the cooling water flow. When ΔT1 or ΔT2 exceeds the set value, it indicates excessive cooling, and the corresponding electric control valve will be controlled to reduce the opening degree and reduce the cooling water flow.

[0054] In this embodiment, the outlet flue gas temperature on the second medium side of the second condenser needs to be controlled at 10°C ± 2°C to ensure that the electric heater 104 accurately heats the flue gas to 80 - 100°C. If the temperature at the outlet of the second condenser fluctuates, the first PLC controller preferentially adjusts the cooling water flow of the second condenser and then makes fine adjustments through the electric heater 104 to avoid excessive energy consumption of the electric heater 104.

[0055] All of the above control valves, the first stop valve, and all temperature sensors are connected to the first PLC controller of the flue gas treatment module through cables. The first PLC controller communicates using the Profibus protocol. In the central DCS system, the inlet and outlet temperatures, cooling water flow, and the opening degree of the electric control valve of the first condenser or the second condenser can be displayed in real time, supporting manual / auto mode switching, which is convenient for operation and maintenance personnel to monitor abnormal conditions. As Figure 3 As shown, the solid amine adsorption module 2 includes two identical adsorption towers, namely the first adsorption tower 201A and the second adsorption tower 201B. High-performance moisture-resistant solid amine adsorbents, such as quaternary ammonium salt-modified silica gel, are filled inside both adsorption towers. The adsorption towers are designed as common fixed-bed adsorption towers to ensure uniform gas flow distribution and effective utilization of the adsorbent. The adsorption towers are provided with a top inlet, a top outlet, a bottom inlet, a bottom outlet, and a side outlet.

[0056] As Figure 3 As shown, the electric heater 104 is connected to the top inlets of the first adsorption tower 201A and the second adsorption tower 201B through the outlet main pipeline of the electric heater 104. A first pressure control valve 205 is provided on the outlet main pipeline of the electric heater 104 to stabilize the inlet pressure (0.5 - 1.0 MPa) during the adsorption stage. First electric control inlet valves 212a and 212b are respectively provided on the inlet branch pipes from the electric heater 104 to the first adsorption tower 201A and the second adsorption tower 201B, and their opening and closing are controlled by the program control valve group 204 to ensure that the first adsorption tower or the second adsorption tower closes the inlet during the regeneration stage and admits gas during the adsorption stage.

[0057] It should be noted that corresponding electric control valves are provided at the top outlet and the bottom inlet to close / open these outlets / inlets.

[0058] During the adsorption stage, the flue gas enters the first adsorption tower 201A or the second adsorption tower 201B through the flue gas inlet pipeline 109 at a pressure of 0.5 - 1.0 MPa and a temperature of 80 - 100 °C with an airspeed of 1200 h -1 . The CO2 in the flue gas undergoes a chemisorption reaction with the amino functional groups on the surface of the solid amine adsorbent to form stable compounds, such as bicarbonates, and is thus efficiently captured. The adsorption process usually lasts for 5 - 10 minutes. When the adsorbent in the first adsorption tower 201A or the second adsorption tower 201B approaches saturation, the process will switch to the regeneration stage.

[0059] As Figure 3 shown, the bottom gas outlet of the first adsorption tower 201A is connected to the first flue gas exhaust pipeline 213; a first exhaust valve 206 is provided on the first flue gas exhaust pipeline 213; the bottom gas outlet of the second adsorption tower 201B is connected to the second flue gas exhaust pipeline 214; a second exhaust valve 207 is provided on the second flue gas exhaust pipeline 214; for the purified flue gas, the CO2 concentration is reduced to below 1000 ppm and is discharged into the atmosphere after being cooled through the first flue gas exhaust pipeline 213 or the second flue gas exhaust pipeline 214. The first exhaust valve 206 or the second exhaust valve 207 is only opened during the adsorption stage to discharge the purified flue gas; it is closed during the regeneration stage to prevent reverse air flow.

[0060] Taking the first adsorption tower as an example, at the beginning of the adsorption stage, the first electronically controlled intake valve 212a and the first exhaust valve 206 are opened synchronously, and the flue gas continuously flows into the first adsorption tower and is discharged in real time after adsorption treatment; when the adsorbent approaches saturation (about 5 - 10 minutes), the first electronically controlled intake valve 212a and the first exhaust valve are closed, and then the regeneration stage is entered. Adsorption stage: The first electronically controlled intake valve 212a and the first exhaust valve are linked to form a continuous processing channel of "intake - adsorption - exhaust". As Figure 3 shown, both the first adsorption tower 201A and the second adsorption tower 201B are connected to the first vacuum pump 202 and the CO2 storage tank 203. Specifically, the first adsorption tower 201A, the second adsorption tower 201B, the first vacuum pump 202, and the CO2 storage tank 203 are connected through the first CO2 pipeline 215; specifically, the side gas outlet of the first adsorption tower 201A is connected to the first vacuum pump 202, and a first inlet valve 208 is provided between the first vacuum pump 202 and the first adsorption tower 201A; the first vacuum pump 202 is connected to the side gas outlet of the second adsorption tower 201B, and a second inlet valve 209 is provided between the first vacuum pump 202 and the second adsorption tower 201B; the first vacuum pump 202 is connected to the CO2 storage tank 203.

[0061] Furthermore, a first outlet valve 210 is provided between the first vacuum pump 202 and the CO2 gas storage tank 203 to control the connection between the vacuum pump and the gas storage tank, facilitating equipment maintenance.

[0062] It can be understood that when the first outlet valve 210 is opened, the first inlet valve 208 is opened, and the second inlet valve 209 is closed, the first vacuum pump 202 starts. At the same time, the side air outlet of the first adsorption tower 201A is opened, and other air inlets or outlets are closed; it is used for vacuum desorption during the (pressure swing adsorption) PSA regeneration in the first adsorption tower 201A to reduce the pressure inside the first adsorption tower 201A to release CO2. It can also be understood that the pumping rate (or power) of the first vacuum pump 202 can meet the volume and regeneration cycle of the first adsorption tower or the second adsorption tower.

[0063] In the regeneration stage, the pressure swing adsorption (PSA) mode is adopted. First, the first vacuum pump 202 evacuates the first adsorption tower 201A or the second adsorption tower 201B, quickly reducing the pressure to 0.1 - 0.2 MPa. The rapid pressure drop is used to achieve the physical desorption of CO2, enabling the adsorbent to desorb and regenerate. At this time, the CO2-rich gas is transported into the CO2 gas storage tank 203 through the first CO2 pipeline 215 under the action of the first vacuum pump 202.

[0064] As Figure 3 shown, the bottom air inlets of both the first adsorption tower 201A and the second adsorption tower 201B are connected to the purge gas pipeline 216; a check valve 211 is provided on the purge gas pipeline 216, and the check valve 211 adopts an electrically controlled valve; it prevents the reverse flow of the CO2 product gas, thus ensuring the unidirectionality of the process. The top air outlet of the first adsorption tower 201A and the top air outlet of the second adsorption tower 201B are connected to the CO2 gas storage tank 203 through the second CO2 pipeline 217.

[0065] To further improve the regeneration efficiency and the purity of the product CO2, after the desorption of the first adsorption tower 201A or the second adsorption tower 201B is completed, a small amount of CO2 product gas with a purity ≥ 95% is introduced into the first adsorption tower 201A or the second adsorption tower 201B through the second CO2 pipeline 217 as a purge gas to purge the adsorption bed layer of the first adsorption tower 201A or the second adsorption tower 201B, taking away the residual CO2. The amount of the purge gas is 5% of the adsorption gas volume.

[0066] The desorption and purge processes usually last for 3 - 5 minutes, and the regeneration efficiency can reach over 95%.

[0067] The solid amine adsorption module 2 further includes a programmable control valve group 204. The programmable control valve group 204 is connected to the first pressure regulating valve, as well as all the above-mentioned electronically controlled intake valves (the first electronically controlled intake valve, the second electronically controlled intake valve), inlet valves (the first inlet valve, the second inlet valve), exhaust valves (the first exhaust valve, the second exhaust valve), and the electronically controlled valves of the two adsorption towers (the electronically controlled valves of the top gas outlet and the bottom gas inlet). At the same time, it is also connected to the first vacuum pump 202, the first outlet valve 210, and the one-way valve 211, and is used to control the opening and closing of each intake port / gas outlet of the first adsorption tower 201A and the second adsorption tower 201B, to control the start and stop of the first vacuum pump 202, and to control the opening and closing of the first outlet valve 210 and the one-way valve 211. The programmable control valve group 204 is connected to the second PLC controller of the solid amine adsorption module 2 and is controlled by the second PLC controller of the solid amine adsorption module 2 according to the preset logic.

[0068] For example, when the first adsorption tower 201A is adsorbing, the port 212a of the first electronically controlled intake valve of the first adsorption tower 201A is opened, the top gas outlet and the bottom gas inlet are closed, the first inlet valve 208 is closed, the first exhaust valve 206 is opened, and the flue gas enters the first adsorption tower 201A for adsorption treatment and the treated flue gas is discharged in time.

[0069] When the adsorption in the first adsorption tower is approaching saturation, at this time, the first electronically controlled intake valve 212a is closed, and the first exhaust valve 206 is closed; the first intake valve 208 is opened, the first vacuum pump is started, and the first outlet valve 210 is opened; the first adsorption tower begins to enter the regeneration stage.

[0070] When the first adsorption tower 201A is adsorbing, the second adsorption tower 201B is in the regeneration stage. The second electronically controlled intake valve 212b of the second adsorption tower 201B is closed, the second exhaust valve 207 is closed, and the second inlet valve 209 is opened.

[0071] The top gas outlet and the bottom gas inlet of the second adsorption tower are closed, the first vacuum pump 202 is opened for desorption regeneration. At the same time, the adsorbed CO2 is sent to the CO2 storage tank 203 for storage.

[0072] After desorption regeneration, the first vacuum pump 202 is closed, the second inlet valve 209 is opened. At this time, the bottom gas inlet and the top gas outlet are opened, the one-way valve 211 is opened, and the purging work begins. Next, the second adsorption tower 201B will enter the adsorption stage.

[0073] That is, the adsorption stage or regeneration stage of the first adsorption tower and the second adsorption tower is carried out alternately. In this embodiment, the pressure swing adsorption (PSA) mode is adopted in the solid amine adsorption module, and at the same time, the carbon dioxide product gas with a purity of ≥ 95% is used as the purge gas for adsorbent regeneration, realizing the recycling of energy and resources inside the system while effectively reducing energy consumption and operating costs; compared with the traditional temperature swing adsorption (TSA) or chemical desorption and other regeneration methods, it shows significant advantages of lower energy consumption and faster regeneration speed; at the same time, the recycling of the product carbon dioxide gas further reduces the regeneration energy consumption, providing an efficient and sustainable solution for carbon capture in the carbon industry.

[0074] In this embodiment, the solid amine adsorption module 2 adopts a process of two adsorption towers in parallel, which can realize continuous CO2 capture and adsorbent regeneration; the two adsorption towers alternately carry out adsorption and regeneration operations to ensure the continuous operation of the system and improve the capture efficiency; the desorbed CO2-rich gas is collected into the CO2 storage tank 203 and used as the feed gas source for the membrane separation module 3, avoiding the direct contact between the flue gas and the membrane separation module 3.

[0075] The process switching and process control inside the solid amine adsorption module 2 are automatically controlled by the program-controlled valve group 204. In addition, the internal pipes of the solid amine adsorption module 2 are made of carbon steel lined with Teflon to prevent the corrosion of amine substances.

[0076] As Figure 4 shown, the membrane separation module 3 includes a compressor 301, a molecular sieve dryer 302, a coalescing filter 303, a membrane module 304, a second vacuum pump 305, a booster pump 317, and a CO2 product storage tank 306.

[0077] Among them, the compressor 301, the molecular sieve dryer 302, the coalescing filter 303, and the membrane module 304 are connected in sequence through the CO2-rich gas exhaust pipeline 314; in this embodiment, the outlet direction of the compressor 301 is the molecular sieve dryer 302, the outlet direction of the molecular sieve dryer 302 is the coalescing filter 303, and the outlet direction of the coalescing filter 303 is the membrane module 304. The inlet of the compressor 301 is connected to the outlet of the CO2 storage tank 203 through the CO2-rich gas exhaust pipeline 314.

[0078] It can be understood that the solid amine adsorption module sends the CO2-rich gas into the membrane separation module for high-purity separation and purification. The membrane module does not need to operate under high pressure or be connected in series in multiple stages when separating the CO2-rich gas, with low operating energy consumption. And before the solid amine adsorption module sends the CO2-rich gas into the membrane separation module, it first discharges the purified flue gas, which can further avoid the pollution of the membrane module and ensure the separation efficiency and service life of the membrane module.

[0079] The CO2-rich gas (with a concentration of 60%-80%) discharged from the solid amine adsorption module 2 enters the compressor 301 through the CO2-rich gas exhaust pipeline 314 for compression and temperature rise. The compressor 301 can be a screw compressor or a piston compressor, and is selected according to the processing capacity and pressure requirements. In this embodiment, the CO2-rich gas enters the compressor 301, the pressure is increased to 0.8-1.2 MPa, and the temperature is raised to 40-50 °C.

[0080] The CO2-rich gas after pressure and temperature rise enters the molecular sieve dryer 302 and the coalescing filter 303 in sequence for refined pretreatment. The molecular sieve dryer 302 is filled with a high-efficiency molecular sieve adsorbent inside to further remove trace moisture in the CO2-rich gas, ensure that the moisture dew point is lower than -40 °C, and prevent the influence of moisture on the performance of the membrane module 304.

[0081] The coalescing filter 303 is used to remove oil mist and particulate matter in the CO2-rich gas, ensure that the oil mist concentration is lower than 0.1 mg / m 3 , and protect the membrane module 304 from pollution and blockage. The processed CO2-rich gas enters the membrane module 304 for membrane separation and purification.

[0082] Furthermore, a second stop valve 307 is provided between the CO2 storage tank 203 and the compressor 301; a third stop valve 308 is provided between the compressor 301 and the molecular sieve dryer 302; a fourth stop valve 309 is provided between the molecular sieve dryer 302 and the coalescing filter 303 to control the on-off of the pipeline.

[0083] The membrane module 304 is connected to the second vacuum pump 305, the booster pump 317, and the CO2 product storage tank 306 in sequence through the CO2 product outlet pipeline 316; that is, the permeate side direction of the membrane module 304 is the second vacuum pump 305, the outlet direction of the second vacuum pump 305 is the booster pump 317, and the outlet direction of the booster pump 317 is the CO2 product storage tank 306.

[0084] Furthermore, a fifth stop valve 312 is provided between the second vacuum pump 305 and the booster pump 317; a purge gas pipeline 216 is connected to the outlet of the CO2 product storage tank 306.

[0085] The outlet of the CO2 product gas storage tank 306 is connected to the purging gas pipeline 216, and the product gas is sent into the first adsorption tower 201A or the second adsorption tower 201B for purging. It should be noted that since the first adsorption tower 201A or the second adsorption tower 201B has been evacuated to 0.1 - 0.2 MPa (low pressure state) by the first vacuum pump 202 during the regeneration stage, after the CO2 rich gas enters the membrane separation module from the CO2 gas storage tank 203, it is first pressurized to 0.8 - 1.2 MPa (the optimal operating pressure of the membrane module 304) by the compressor 301, and then the high-purity CO2 (permeate side) separated by the membrane module 304 is enriched by the second vacuum pump 305 and finally lifted to 2.0 MPa by the booster pump 317 and stored in the CO2 product gas storage tank 306.

[0086] At this time, the pressure of the CO2 product gas storage tank 306 is 2.0 MPa, which is significantly higher than the pressure during the regeneration of the first adsorption tower 201A or the second adsorption tower 201B. Relying on this pressure difference, when the one-way valve 211 is opened and the bottom air inlet of the first adsorption tower 201A or the second adsorption tower 201B is opened, the purging gas can naturally flow into the bottom of the first adsorption tower 201A or the second adsorption tower 201B.

[0087] The CO2 product purging gas from the CO2 product gas storage tank 306 enters the bottom of the first adsorption tower 201A or the second adsorption tower 201B through the purging gas pipeline 216, purges the adsorption bed layer and takes away the residual CO2; the purged CO2 gas enters the CO2 gas storage tank 203 under the action of the pressure difference through the second CO2 gas pipeline 217, thus completing the regeneration process of the adsorbent, and the regenerated adsorbent can then enter the next adsorption cycle.

[0088] Furthermore, a second pressure regulating valve 310 is provided at the inlet of the membrane module 304, and a third pressure regulating valve 311 is provided on the permeate side, which is used to adjust the tail gas emission amount and balance the pressure difference between the retentate side and the permeate side of the membrane module.

[0089] Furthermore, the retentate side of the membrane module 304 is connected to the tail gas outlet pipeline 315. The pressure on the retentate side of the membrane module 304 (similar to the pressure before the membrane, about 0.8 - 1.2 MPa) is much higher than the atmospheric pressure, and the tail gas can be naturally discharged by relying on its own pressure; a sixth stop valve 313 is provided on the tail gas outlet pipeline 315.

[0090] It should be noted that the membrane module 304 is the core equipment of the membrane separation module 3, which adopts a highly selective hollow fiber composite membrane, such as a membrane material with a CO2 / N2 separation coefficient ≥ 40. At a pre-membrane operating pressure of 0.8 - 1.2 MPa and an operating temperature of 30 - 40 °C, CO2 preferentially permeates through the membrane module and is enriched on the permeate side of the membrane module, while inert gases such as N2 and Ar are retained on the retentate side of the membrane module. The pressure on the retentate side of the membrane module (similar to the pre-membrane pressure, about 0.8 - 1.2 MPa) is much higher than the atmospheric pressure, and inert gases such as N2 and Ar are discharged naturally as tail gases through the tail gas outlet pipeline 315 by their own pressure.

[0091] To improve the membrane separation efficiency and CO2 recovery rate, a second vacuum pump 305 is connected to the permeate side of the membrane module 304 to maintain a low pressure of 0.1 - 0.2 MPa, increase the pressure difference across the membrane module 304, and promote the permeation of CO2. The highly pure CO2 gas (purity ≥ 95%) enriched on the permeate side is collected through the CO2 product outlet pipeline 316 and stored in the CO2 product gas storage tank 306, or directly transported to the user side.

[0092] A third PLC controller is set in the membrane separation module 3. The third PLC controller is connected to the sensors of the following devices through the "analog input module (AI)":

[0093] The third PLC controller is connected to the inlet and outlet pressure sensors of the compressor 301 (monitoring the pre-membrane pressure of 0.8 - 1.2 MPa), and the third PLC controller is connected to the dew point sensor of the molecular sieve dryer 302 (RS485 communication, monitoring the moisture dew point < -40 °C); the third PLC controller is connected to the differential pressure sensor of the coalescing filter (monitoring oil mist / particle blockage and triggering a replacement alarm); the third PLC controller is also connected to the feedback signals of the pressure regulating valves on both sides of the membrane module 304 (0 - 10V voltage, confirming the stability of the pressure difference);

[0094] The third PLC controller controls the following devices through the "digital output module (DO)": The third PLC controller is connected to the start-stop relay of the compressor (24V DC signal, with an overload protection contactor); the third PLC controller is connected to the electric actuators of all stop valves in the membrane separation module (open / close signal, feedback valve status); the third PLC controller is connected to the frequency converter controller of the second vacuum pump (Modbus protocol, adjusting the pumping rate to match the membrane separation efficiency);

[0095] The third PLC controller is connected to the central DCS system through the Profinet industrial Ethernet to upload operation data in real time (such as the current of the compressor, the pressure on the permeate side of the membrane module), and receive remote control instructions (such as manually switching the valve mode).

[0096] The CO2-rich gas (60%-80%) treated by the solid amine adsorption module 2 enters the membrane separation module 3. Since impurities have been efficiently removed, the membrane module 304 (such as a hollow fiber composite membrane) can operate stably for a long time, the CO2 purity on the permeate side is ≥95%, and the energy consumption is significantly reduced. In addition, the pipes inside the membrane separation module 3 are made of carbon steel to meet the design requirements of pressure vessels.

[0097] Between the solid amine adsorption module 2 and the membrane separation module 3, they are connected by a carbon steel pipe lined with Teflon. The interface parameters are CO2-rich gas (concentration 60%-80%) and pressure 0.1-0.2 MPa. Between the membrane separation module 3 and the CO2 product gas storage tank 306 / export pipeline, they are connected by a carbon steel pipe. The interface parameters are CO2 purity ≥95%, dew point < -40°C, and pressure 2.0 MPa.

[0098] In this embodiment, the internal devices of the flue gas treatment module 1 are connected in series, and the flue gas flows through each device in turn for treatment; inside the solid amine adsorption module 2, the first adsorption tower 201A and the second adsorption tower 201B are connected in parallel, and the adsorption and regeneration operations are carried out alternately; the internal devices of the membrane separation module 3 are connected in series, and the CO2-rich gas flows through each device in turn for purification. The flue gas treatment module 1, the solid amine adsorption module 2, and the membrane separation module 3 are all equipped with independent PLC controllers, which are responsible for the control, data acquisition, or safety protection of the internal devices of their respective modules; for example, in the membrane separation module, it can be set that when the pressure on the retentate side of the membrane module exceeds 1.3 MPa, the third PLC controller automatically triggers the following actions: close the second shut-off valve 307; open the sixth shut-off valve 313 to relieve pressure; send an audible and visual alarm to the DCS (red flashing of pressure, accompanied by a buzzer).

[0099] In this embodiment, the internal devices of each module are highly integrated and can be encapsulated in a standardized container-type frame. Each pipe is seamlessly docked and deployed in a "plug and play" manner through standardized interfaces; this design can shorten the on-site installation and commissioning cycle, reduce the installation difficulty and cost, and at the same time endow the system with excellent flexibility and scalability; it is convenient for system maintenance, repair, and rapid troubleshooting of faults, and improves the reliability and operation efficiency of the system.

[0100] Embodiment 2

[0101] This embodiment discloses a capture method of a modular carbon capture system for flue gas treatment in the carbon industry, which uses a modular carbon capture system for flue gas treatment in the carbon industry disclosed in Embodiment 1. The specific steps are as follows:

[0102] Flue gas treatment: The flue gas from the carbon production line after preliminary denitrification, desulfurization, and dust removal pretreatment enters the roof-type demister to remove larger-sized droplets and liquid water in the flue gas; then it enters the first condenser and the second condenser in sequence for deep cooling, drying, and dehydration; finally, it enters the electric heater to be heated to the optimal adsorption temperature of the solid amine adsorption module;

[0103] Adsorption and regeneration: The treated flue gas enters the first adsorption tower 201A to adsorb CO2. After the adsorption, the flue gas is discharged from the first adsorption tower 201A. Then the first adsorption tower 201A enters the regeneration stage of the catalyst, and the adsorbed CO2 is sent to the CO2 storage tank 203 for storage; at the same time, the treated flue gas enters the second adsorption tower 201B to adsorb CO2; the adsorption stage or regeneration stage of the first adsorption tower 201A and the second adsorption tower 201B are carried out alternately;

[0104] Collection: The CO2 stored in the CO2 storage tank 203 is compressed and heated by a compressor, and then sent to the molecular sieve dryer 302 to further remove the trace moisture in the CO2-rich gas; then it is sent to the coalescing filter 303 to remove the oil mist and particulate matter in the CO2-rich gas; then it is sent to the membrane module 304 for membrane separation and purification; finally, it is sent to the CO2 product storage tank 306 for storage after being pressurized by the booster pump 317.

[0105] During the adsorption and regeneration process, after desorption and regeneration, a small amount of CO2 product gas is introduced into the bottom of the first adsorption tower 201A or the second adsorption tower 201B for purging; the CO2 product gas uses the product gas from the CO2 product storage tank 306.

[0106] Although the specific implementation manners of the present invention are described above in conjunction with the drawings, it is not a limitation to the protection scope of the present invention. Those skilled in the art should understand that based on the technical solutions of the present invention, various modifications or deformations that can be made by those skilled in the art without creative efforts are still within the protection scope of the present invention.

Claims

1. A modular carbon capture system for flue gas treatment in the carbon industry, characterized in that: It includes a flue gas treatment module, a solid amine adsorption module and a membrane separation module which are connected in sequence; The flue gas treatment module includes a ridge-type demister, a first condenser, a second condenser, and an electric heater which are sequentially connected through a flue gas intake pipeline; The solid amine adsorption module includes two identical adsorption towers connected in parallel, both of which are connected to the first vacuum pump and the CO2 gas storage tank through the first CO2 gas pipeline; the bottom air inlet of the adsorption tower is connected to the purge gas pipeline; a one-way valve is arranged on the purge gas pipeline; the top air outlet of the adsorption tower is connected to the CO2 gas storage tank through the second CO2 gas pipeline; the adsorption stage or regeneration stage of the two adsorption towers is carried out alternately; The membrane separation module includes a compressor, a molecular sieve dryer, a coalescing filter, a membrane assembly, a second vacuum pump, a booster pump and a CO2 product gas storage tank which are connected in sequence; the CO2 product gas storage tank is connected to a purge gas pipeline.

2. A modular carbon capture system for flue gas treatment in the carbon industry according to claim 1, characterized in that: The electric heater adopts electric heating wire or PTC heating element to accurately heat the flue gas temperature to the optimal adsorption temperature range of the solid amine adsorption module; the flue gas inlet pipeline adopts a stainless steel pipe; a first pressure regulating valve is arranged on the main pipeline of the electric heater outlet to stabilize the inlet pressure of the two adsorption towers during the adsorption stage.

3. A modular carbon capture system for flue gas treatment in the carbon industry according to claim 1, characterized in that: A first stop valve is arranged at the inlet of the ridge-type demister; a regulating valve is arranged between every two adjacent devices of the ridge-type demister, the first condenser, the second condenser and the electric heater; the regulating valve and the first stop valve are both electrically controlled valves, and the electric heater and the electrically controlled valve are both connected to the first PLC controller of the flue gas treatment module.

4. A modular carbon capture system for flue gas treatment in the carbon industry according to claim 2, characterized in that: The adsorption tower also includes a top air inlet, a bottom air outlet, and a side air outlet. The top air inlet is connected to the air inlet branch of the electric heater outlet main pipeline. An electrically controlled air inlet valve is arranged on the air inlet branch. The bottom air inlet and the top air outlet are both provided with corresponding electrically controlled valves.

5. A modular carbon capture system for flue gas treatment in the carbon industry according to claim 4, characterized in that: The bottom air outlets of the two adsorption towers are connected to the flue gas exhaust pipeline, and exhaust valves are arranged on the flue gas exhaust pipeline; the side air outlets of the two adsorption towers are connected to the first vacuum pump, and an inlet valve is arranged between the adsorption tower and the first vacuum pump; the first vacuum pump is connected to the CO2 gas storage tank, and a first outlet valve is arranged between the first vacuum pump and the CO2 gas storage tank; the internal pipeline of the solid amine adsorption module is made of carbon steel and lined with Teflon.

6. A modular carbon capture system for flue gas treatment in the carbon industry according to claim 5, characterized in that: The solid amine adsorption module also includes a program-controlled valve group, which is connected to all valves of the solid amine adsorption module and the first vacuum pump; the program-controlled valve group is connected to the second PLC controller of the solid amine adsorption module.

7. A modular carbon capture system for flue gas treatment in the carbon industry according to claim 1, characterized in that: The inlet of the compressor is connected to the outlet of the CO2 gas storage tank through a CO2 rich gas exhaust pipeline; a stop valve is set between every two adjacent devices of the CO2 gas storage tank, the compressor, the molecular sieve dryer, and the coalescing filter; and a stop valve is set between the second vacuum pump and the booster pump.

8. A modular carbon capture system for flue gas treatment in the carbon industry according to claim 1, characterized in that: A pressure regulating valve is provided at the inlet and permeate side of the membrane assembly; the retention side of the membrane assembly is connected to the tail gas outlet pipeline; a stop valve is provided on the tail gas outlet pipeline; the pipeline inside the membrane separation module is made of carbon steel.

9. A capture method of a modular carbon capture system for flue gas treatment in the carbon industry according to any one of claims 1 to 8, characterized in that: The specific steps are as follows: After the preliminary denitrification, desulfurization and dust removal pretreatment, the flue gas enters the roof-type demister to remove the larger droplets and liquid water in the flue gas; then it enters the first condenser and the second condenser in turn for deep cooling, drying and dehydration; finally it enters the electric heater to be heated to the optimal adsorption temperature of the solid amine adsorption module; The treated flue gas enters one of the two adsorption towers to adsorb CO2. After the adsorbed flue gas is discharged from the current adsorption tower, the current adsorption tower enters the catalyst regeneration stage and sends the adsorbed CO2 into the CO2 gas storage tank for storage; at the same time, the treated flue gas enters the other adsorption tower of the two adsorption towers to adsorb CO2; the adsorption stage or regeneration stage of the two adsorption towers is carried out alternately; The CO2 stored in the CO2 gas storage tank is compressed and heated by a compressor, and then sent to a molecular sieve dryer to further remove trace moisture in the CO2 rich gas; then it is sent to a coalescing filter to remove oil mist and particulate matter in the CO2 rich gas; then it is sent to a membrane assembly for membrane separation and purification; and finally it is sent to a CO2 product gas storage tank for storage.

10. The capture method of a modular carbon capture system for flue gas treatment in the carbon industry according to claim 9, characterized in that: During the adsorption and regeneration process, after desorption and regeneration, a small amount of CO2 product gas is introduced into the bottom of the adsorption tower for purge work; the CO2 product gas uses the product gas from the CO2 product gas storage tank.

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