Membrane separation technology-based low-energy-consumption dual-carbon capture system

Abstract

The invention provides a low-energy-consumption dual-carbon capture system based on a membrane separation technology, and belongs to the technical field of dual-carbon capture. Comprising a condensation water removal unit, a first CO2 trapping unit for trapping CO2 in gas, a first CO trapping unit for trapping CO in the gas and a nitrogen oxide reaction unit which are sequentially connected in the gas flow direction, according to the system, different trapping units are sequentially arranged in the gas flow direction, all the units are matched with one another, CO2, CO and nitric oxide can be effectively trapped, various pollutants can be treated in one system at the same time through the integrated design, useful components in gas are recycled to the maximum extent, resource waste is avoided, and the system is suitable for industrial production. According to the CO2 and CO dual-carbon capture system, the effective recycling of resources is realized, the residual CO2 after the first capture can be captured again, and the content of CO2 and CO in the gas is further reduced, so that the capture rate of the whole system on CO2 and CO is obviously improved, and the dual-carbon target can be better realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of dual carbon capture, and in particular is a low-energy dual carbon capture system based on membrane separation technology. Background Art

[0002] With the acceleration of global industrialization, energy consumption continues to increase, and the combustion of large amounts of fossil fuels leads to CO 2 , CO and nitrogen oxides (NO x ) and other pollutants, which not only cause serious harm to the environment, such as leading to global warming, acid rain, and deterioration of air quality, but also reduce greenhouse gas emissions in the context of responding to climate change.

[0003] Traditional pollutant capture technologies often target single pollutants, such as some CO 2 Capture technology focuses on separating CO from post-combustion exhaust gases 2 , but for the coexistence of CO and NO x The processing capacity is limited, and the existing capture technologies have major problems in terms of energy consumption, such as some CO 2 The capture method requires high temperature, high pressure and other conditions, which leads to a large amount of energy consumption, increases the capture cost, and reduces the economy and sustainability of the capture process.

[0004] As a new separation technology, membrane separation technology has the advantages of energy saving, high efficiency, easy operation and no secondary pollution, and has received extensive attention in the field of carbon capture. Membrane separation uses the difference in the permeation rate of gas molecules in the membrane to achieve separation. By selecting appropriate membrane materials and membrane components, CO 2 , efficient separation of CO.

[0005] Existing capture technologies have major problems in terms of energy consumption, such as some CO 2 The capture method requires high temperature, high pressure and other conditions, which leads to a large amount of energy consumption, increases the capture cost, and reduces the economy and sustainability of the capture process. 2 There is a lack of effective integrated design for capturing CO and nitrogen oxides, and the capture is not thorough. Summary of the invention

[0006] In view of the above-mentioned problems, the present invention provides a low-energy dual-carbon capture system based on membrane separation technology.

[0007] The technical solution of the present invention is: a low-energy dual-carbon capture system based on membrane separation technology, comprising a condensation and water removal unit connected in sequence along the air flow direction, a 2 The first CO2 A capture unit, a first CO capture unit for capturing CO in the gas, and a nitrogen oxide reaction unit;

[0008] The first CO 2 The capture unit has two outlets, one of which is connected to a second CO 2 A capture unit, another outlet of which is connected to the first CO capture unit;

[0009] First CO 2 Capture unit and second CO 2 Each capture unit is equipped with a CO 2 Separation membrane, the first CO 2 Capture unit and second CO 2 The capture units are all connected with pressure regulating devices;

[0010] The first CO capture unit has two outlets, the first outlet is connected to the second CO capture unit, and the second outlet is connected to the nitrogen oxide reaction unit;

[0011] A CO separation membrane is provided in the first CO capture unit and the second CO capture unit, and a gas premixing box is connected to the inlet of the first CO capture unit and the second CO capture unit;

[0012] The second CO capture unit, the nitrogen oxide reaction unit and the second CO 2 The capture units are all connected to tail gas storage tanks.

[0013] Furthermore, the condensation and water removal unit includes a first heat exchanger, a multi-stage condensation component connected to the first heat exchanger, and a 2 The steam-water separator of the capture unit, the multi-stage condensation assembly is composed of a plurality of condensers connected in series in sequence, and a flow regulating valve and a temperature sensor are arranged between two adjacent condensers.

[0014] Note: The air to be treated enters the first CO 2 When in the capture unit, first, the temperature is lowered by the first heat exchanger, so that the water vapor in the air to be treated is easier to condense into liquid water in the subsequent condensation process, and then, it passes through each condenser connected in series in sequence, and the temperature is gradually lowered by the condenser, so that the water vapor in the air to be treated is continuously condensed into liquid water, thereby achieving the purpose of water removal. The temperature of the air after condensation by the previous condenser is monitored in real time by the temperature sensor between the two adjacent condensers. According to the temperature feedback, the flow rate of the air flowing into the next condenser can be adjusted by the flow regulating valve. The air treated by the multi-stage condensation component enters the steam-water separator for steam-water separation, which can more thoroughly remove the moisture in the air and effectively avoid the water vapor on CO 2Interference with the capture process.

[0015] Furthermore, the first CO 2 The capture unit includes a CO2 capture unit connected in parallel to the condensation and water removal unit. 2 Membrane separator and absorber, the CO 2 The membrane separator is connected to a first storage tank, a heater is provided on the absorption tower, a filter is connected to the side wall of the absorption tower and a second heat exchanger is provided at the connection, and the filter is connected to a second storage tank.

[0016] Note: The air treated by the condensation and water removal unit will enter the first CO 2 The capture unit and the CO 2 In the membrane separator and absorption tower, CO 2 Membrane separator for CO in air 2 Membrane separation is performed and the captured CO is stored in the first storage tank. 2 The separated gas enters the first CO capture unit, where the CO in the air is absorbed by the adsorbent in the absorption tower. 2 Adsorption capture and formation of liquid CO 2 The separated gas enters the first CO capture unit, and the captured liquid CO 2 After being discharged and cooled by the second heat exchanger, it is filtered through a filter and stored in the second storage tank. By combining and performing the above two capture methods simultaneously, CO 2 The capture efficiency can be improved to reduce emissions. The respective operating parameters can also be adjusted according to actual conditions to improve the flexibility and adaptability of the system and better cope with CO2 of different concentrations and flows. 2 Capture demand.

[0017] Furthermore, the CO 2 The membrane separator comprises a first shell having a first air inlet and a first air outlet on both sides, a diverter plate arranged in the first shell and close to the first air inlet, the CO 2 The separation membrane is arranged in the first shell and connected to the diverter plate. 2 The separation membrane is composed of a plurality of tubular capture membranes connected to the diverter disk through a plurality of inlet branches and provided with inlet valves at the connection points. A reflux disk is connected to each tubular capture membrane and on the side opposite to the diverter disk through a plurality of outlet branches. A CO 2 Discharge pipe.

[0018] Description: CO 2 Membrane separator for CO in air 2When performing membrane separation capture, air first enters the splitter plate through the first air inlet, and the splitter plate evenly distributes the incoming air and enters the corresponding tubular capture membrane through each air inlet branch pipe. 2 can flow out of the capture membrane and pass through the CO 2 The exhaust pipe is discharged into the first storage tank, and the remaining gas after separation flows into the reflux disk through the outlet branch pipe and is discharged through the first outlet. Compared with a single flat membrane structure, multiple tubular capture membranes can provide a larger membrane area in a limited space, thereby improving CO 2 Separation efficiency with other gases, more CO 2 The molecules have the opportunity to contact the surface of the tubular capture membrane and pass through the tubular capture membrane for separation. If a tubular capture membrane or an air inlet valve fails, it can be located and replaced relatively easily without affecting the normal operation of other parts of the entire membrane separator, reducing maintenance costs and difficulty.

[0019] Furthermore, the tubular capture membrane includes a plurality of first spiral capture membrane bodies connected one-to-one with each of the air inlet branches, and a plurality of second spiral capture membrane bodies uniformly distributed circumferentially around the periphery of each first spiral capture membrane body. The plurality of second spiral capture membrane bodies around the periphery of each first spiral capture membrane body are connected to the reflux disk at one end and to the air inlet end of the first spiral capture membrane body at the other end, and a one-way valve is provided at the connection, and an outlet valve is provided on each outlet branch.

[0020] Note: The gas enters each tubular capture membrane from left to right through the inlet branch. At this time, close the inlet valve at the inlet branch and the outlet valve on the corresponding outlet branch. First, the gas passes through the main body of each first spiral capture membrane. Due to its spiral structure, the contact area between the gas and the first spiral capture membrane is increased, thereby increasing the CO 2 The gas will flow from the tubular capture membrane into the reflux plate, and then flow back from right to left through each second spiral capture membrane body outside the first spiral capture membrane body to the first spiral capture membrane body for repeated treatment, which can ensure that the CO in the gas 2 After the capture is completed, the gas is discharged by opening the outlet valve on the outlet branch pipe. Since a one-way valve is provided at the connection between the second spiral capture membrane body and the inlet end of the first spiral capture membrane body, the gas near the diverter plate can only flow from the second spiral capture membrane body into the first spiral capture membrane body, and cannot flow back, which greatly improves the overall CO 2 Capture rate.

[0021] Furthermore, there are two pressure regulating devices, which are respectively arranged at the first CO 2 Capture unit and the second CO 2 At the inlet of the capture unit, the pressure regulating device includes a pressure sensor and a regulating valve.

[0022] Description: Gas enters the first CO 2 Capture unit or second CO 2 When inside the capture unit, the pressure sensor detects the air pressure value, and the air pressure is adjusted according to the opening of the regulating valve to control the air pressure. 2 Capture unit or second CO 2 The gas pressure of the capture unit is maintained within a stable range, so that the CO 2 Each step in the capture process can be carried out under ideal pressure conditions, thereby improving CO 2 This improves the collection efficiency and, at the same time, keeps the gas pressure within an appropriate range, avoiding frequent startup of excessive pressurization or decompression equipment, thereby reducing this part of additional energy consumption.

[0023] Furthermore, the first CO capture unit includes 2 The capture unit is connected to a CO membrane separator and a CO storage tank, wherein the CO membrane separator comprises a second shell having a second air inlet and a second air outlet on both sides, respectively, and the CO separation membrane arranged in the second shell. The CO storage tank is connected to the bottom end of the second shell, and the second CO capture unit has the same structure as the first CO capture unit.

[0024] Description: After the first CO 2 Before the gas treated by the capture unit flows into the first CO capture unit, it is mixed by a gas premixing box to make the gas composition entering the CO membrane separator uniform, which can ensure a stable and appropriate concentration difference on both sides of the CO membrane separator. The stable concentration difference helps to improve the selective permeability of the CO separation membrane to CO, thereby improving the membrane separation efficiency, so that more CO can be separated through the membrane. The captured CO is stored in a CO storage tank, and the separated gas flows into the nitrogen oxide reaction unit for subsequent treatment.

[0025] Furthermore, the nitrogen oxide reaction unit includes a reactor body, a catalyst bed disposed in the reactor body, and a nitrogen 2 Storage tank, constant temperature heater installed in the reactor body.

[0026] Description: When the nitrogen oxide reaction unit is in use, the gas first enters the reactor body, and the catalyst on the catalyst bed adsorbs the nitrogen oxides in the gas and reduces them to nitrogen. 2The storage tank stores nitrogen. At the same time, the inside of the reactor body is heated by a constant temperature heater to improve the adsorption efficiency of the catalyst for nitrogen oxides. The remaining gas is passed into the tail gas storage tank for storage, which can more effectively reduce the nitrogen oxide content in the gas, make the exhaust gas more in line with environmental protection standards, and reduce the risk of environmental pollution. At the same time, it can also maximize the recovery of useful components in the gas and avoid waste of resources.

[0027] Furthermore, the catalyst bed is filled with a VW-Ti type catalyst.

[0028] Description: The synergistic effect of V, W and Ti can provide multiple active sites, which can effectively adsorb nitrogen oxide molecules and reduce the activation energy of the nitrogen oxide reduction reaction. Nitrogen oxides can be quickly and effectively reduced to nitrogen gas, which improves the conversion efficiency of nitrogen oxides and thus more effectively reduces the nitrogen oxide content in the gas.

[0029] Compared with the prior art, the beneficial effects of the present invention are:

[0030] When the low-energy dual carbon capture system based on membrane separation technology of the present invention is used, a condensation and water removal unit, a first CO 2 The capture unit, the first CO capture unit for capturing CO in the gas, and the nitrogen oxide reaction unit, each unit cooperates with each other to be able to 2 This integrated design allows multiple pollutants to be processed simultaneously in one system, maximizing the recovery of useful components in the gas, avoiding resource waste, and achieving effective resource recycling. 2 Capture unit and second CO 2 Each capture unit is connected to a pressure regulating device, which can 2 Capture unit or CO 2 The gas pressure of the capture unit is maintained within a stable range, so that the CO 2 Each step in the capture process can be carried out under ideal pressure conditions, thereby improving CO 2 The capture efficiency is improved, and at the same time, the gas pressure is kept in an appropriate range, avoiding frequent startup of excessive pressurization or decompression equipment, thereby reducing this part of extra energy consumption; and the first CO 2 The capture unit is also connected to a second CO 2 The first CO capture unit is connected to the second CO capture unit, and can also capture the remaining CO after the first capture. 2 Re-capture to further reduce CO in the gas 2 and CO content, thus significantly improving the overall system’s CO2 and CO capture rate, which helps to better achieve the dual carbon goals; the present invention uses membrane separation to achieve CO 2 The efficient separation of CO does not require high temperature and high pressure conditions, which greatly reduces energy consumption and capture costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0032] Figure 2 is a schematic structural diagram of a multi-stage condensation assembly of the present invention;

[0033] Figure 3 CO of the present invention 2 Schematic diagram of the internal structure of a membrane separator;

[0034] Figure 4 is a schematic structural diagram of a tubular capture membrane of the present invention;

[0035] Figure 5 is a side view of a tubular capture membrane of the present invention;

[0036] Figure 6 It is a schematic structural diagram of the first CO capture unit of the present invention.

[0037] Among them, 1-condensation and water removal unit, 10-first heat exchanger, 11-multi-stage condensation component, 110-condenser, 111-flow regulating valve, 112-temperature sensor, 12-steam-water separator, 2-first CO 2 Capture unit, 20-CO 2 Membrane separator, 200-first storage tank, 21-absorption tower, 210-heater, 211-filter, 212-second heat exchanger, 213-second storage tank, 22-pressure regulating device, 220-pressure sensor, 221-regulating valve, 23-first shell, 230-first air inlet, 231-first air outlet, 232-CO 2 Exhaust pipe, 24-dividing plate, 25-tubular capture membrane, 250-inlet branch pipe, 251-inlet valve, 252-outlet branch pipe, 2520-outlet valve, 253-reflux plate, 254-first spiral capture membrane body, 255-second spiral capture membrane body, 256-check valve, 3-first CO capture unit, 30-second CO capture unit, 31-CO separation membrane, 32-gas premixing box, 33-CO membrane separator, 330-second air inlet, 331-second air outlet, 332-second shell, 34-CO storage tank, 4-nitrogen oxide reaction unit, 40-reactor body, 41-catalyst bed, 42-N 2 Storage tank, 43-constant temperature heater, 5-second CO 2Capture unit, 50- tail gas storage tank, 6-CO 2 Separation membrane. DETAILED DESCRIPTION

[0038] In order to further understand the content of the present invention, the present invention is described in detail below through examples.

[0039] Example 1: Figure 1 As shown, a low-energy dual carbon capture system based on membrane separation technology includes a condensation and water removal unit 1 connected in sequence along the air flow direction, a unit for capturing CO in the gas, and a 2 The first CO 2 A capture unit 2, a first CO capture unit 3 for capturing CO in the gas, and a nitrogen oxide reaction unit 4;

[0040] like Figure 2 As shown, the condensation and water removal unit 1 includes a first heat exchanger 10, a multi-stage condensation component 11 connected to the first heat exchanger 10, and a multi-stage condensation component 11 for connecting the multi-stage condensation component 11 and the first CO 2 The steam-water separator 12 of the capture unit 2, the multi-stage condensation assembly 11 is composed of three condensers 110 connected in series, and a flow control valve 111 and a temperature sensor 112 are arranged between two adjacent condensers 110. The air treated by the multi-stage condensation assembly 11 enters the steam-water separator 12 for steam-water separation, which can more thoroughly remove moisture in the air and effectively avoid the water vapor from affecting CO 2 Interference of the capture process, wherein the first heat exchanger 10, the steam-water separator 12, the condenser 110, the flow regulating valve 111 and the temperature sensor 112 all adopt existing technologies, for example, the first heat exchanger 10 adopts a heat exchanger of model BES500-1.6-55-6 / 25-2I, the steam-water separator 12 adopts an existing Spirax Sarco steam-water separator, the condenser 110 adopts an FNH type condenser, the flow regulating valve 111 adopts an existing flow regulating valve with a temperature compensation function, and the temperature sensor 112 adopts a temperature sensor of model KTY81 / 110;

[0041] First CO 2 Capture unit 2 has two outlets, one of which is connected to a second CO 2 The other outlet of the capture unit 5 is connected to the first CO capture unit 3;

[0042] First CO 2 Capture unit 2 and second CO 2 Each capture unit 5 is equipped with a CO 2 Separation membrane 6, first CO 2 Capture unit 2 and second CO 2 The capture units 5 are all connected with a pressure regulating device 22;

[0043] First CO 2 The capture unit 2 includes a CO2 capture unit 2 and a CO2 capture unit 2 connected in parallel to the condensation and water removal unit 1. 2 Membrane separator 20 and absorption tower 21, CO 2 The membrane separator 20 is connected to a first storage tank 200, a heater 210 is provided on the absorption tower 21, a filter 211 is connected to the side wall of the absorption tower 21 and a second heat exchanger 212 is provided at the connection, the filter 211 is connected to a second storage tank 213, and the air treated by the condensation and dehydration unit 1 enters the first CO 2 Capture unit 2, and simultaneously enters CO 2 In the membrane separator 20 and the absorption tower 21, CO 2 Membrane separator 20 for CO in air 2 Membrane separation is performed, and the captured CO is stored in the first storage tank 200. 2 The separated gas enters the first CO capture unit 3, where the CO in the air is absorbed by the adsorbent in the absorption tower 21. 2 Adsorption capture and formation of liquid CO 2 The separated gas enters the first CO capture unit 3, and the captured liquid CO 2 After being discharged and cooled by heat exchange in the second heat exchanger 212, the collected water is filtered by the filter 211 and stored in the second storage tank 213. By combining and performing the above two capture methods simultaneously, the CO 2 The capture efficiency can be improved to reduce emissions. The respective operating parameters can also be adjusted according to actual conditions to improve the flexibility and adaptability of the system and better cope with CO2 of different concentrations and flows. 2 Capture demand, including CO 2 The membrane separator 20, the heater 210, the filter 211 and the second heat exchanger 212 all adopt existing technologies, such as CO 2 The membrane separator 20 may adopt an existing short-circuit membrane carbon dioxide separator, the heater 210 may adopt an existing electromagnetic heater, the filter 211 may adopt an existing Donaldson filter, and the second heat exchanger 212 may adopt a heat exchanger of model BES500-1.6-55-6 / 25-2I;

[0044] like Figure 1 As shown, there are two pressure regulating devices 22, and the two pressure regulating devices 22 are respectively arranged at the first CO 2 Capture unit 2 and second CO 2 At the inlet of the capture unit 5, the pressure regulating device 22 includes a pressure sensor 220 and a regulating valve 221. The gas enters the first CO 2 Capture unit 2 or second CO 2When the air is in the capture unit 5, the air pressure value is detected by the pressure sensor 220, and the air pressure is adjusted according to the opening of the regulating valve 221, so that the air entering the first CO 2 Capture unit 2 or second CO 2 The gas pressure of the capture unit 5 is maintained within a stable range, so that the CO 2 Each step in the capture process can be carried out under ideal pressure conditions, thereby improving CO 2 The collection efficiency is improved, and at the same time, the gas pressure is kept in an appropriate range, avoiding frequent startup of excessive pressurization or decompression equipment, thereby reducing this part of extra energy consumption. Among them, the pressure sensor 220 and the regulating valve 221 both adopt existing technologies. For example, the pressure sensor 220 can adopt a pressure sensor of model MPX2010, and the regulating valve 221 adopts an electric regulating valve of model ZDLP-16P;

[0045] The first CO capture unit 3 has two outlets, the first outlet is connected to the second CO capture unit 30, and the second outlet is connected to the nitrogen oxide reaction unit 4;

[0046] A CO separation membrane 31 is provided in the first CO capture unit 3 and the second CO capture unit 30, and a gas premixing box 32 is connected to the inlet of the first CO capture unit 3 and the second CO capture unit 30;

[0047] The second CO capture unit 30, the nitrogen oxide reaction unit 4 and the second CO 2 The capture units 5 are all connected to a tail gas storage tank 50;

[0048] like Figure 6 As shown, the first CO capture unit 3 includes a first CO 2 The CO2 capture unit 2 is connected to a CO2 membrane separator 33 and a CO2 storage tank 34. The CO2 membrane separator 33 includes a second shell 332 with a second air inlet 330 and a second air outlet 331 on both sides, and a CO2 separation membrane 31 arranged in the second shell 332. The CO2 storage tank 34 is connected to the bottom end of the second shell 332. The second CO2 capture unit 30 has the same structure as the first CO2 capture unit 3. 2 Before the gas processed by the capture unit 2 flows into the first CO capture unit 3, it is mixed by the gas premixing box 32 to make the gas composition entering the CO membrane separator 33 uniform, which can ensure a stable and appropriate concentration difference on both sides of the CO membrane separator 33. The stable concentration difference helps to improve the selective permeability of the CO separation membrane 31 to CO, thereby improving the membrane separation efficiency, so that more CO can be separated through the membrane. The captured CO is stored in the CO storage tank 34, and the separated gas flows into the nitrogen oxide reaction unit 4 for subsequent treatment;

[0049] The nitrogen oxide reaction unit 4 includes a reactor body 40, a catalyst bed 41 disposed in the reactor body 40, and a nitrogen oxide reaction unit 42 connected to the reactor body 40. 2 The storage tank 42 and the constant temperature heater 43 are arranged in the reactor body 40. When the nitrogen oxide reaction unit 4 is in use, the gas first enters the reactor body 40, and the nitrogen oxides in the gas are adsorbed by the catalyst on the catalyst bed 41 and reduced to nitrogen, and then the nitrogen oxides are reduced to nitrogen by the N 2 The storage tank 42 stores nitrogen. At the same time, the interior of the reactor body 40 is heated by the thermostatic heater 43 to improve the adsorption efficiency of the catalyst on nitrogen oxides. The remaining gas is passed into the tail gas storage tank 50 for storage, which can more effectively reduce the nitrogen oxide content in the gas, make the discharged gas more in line with environmental protection standards, reduce the risk of environmental pollution, and at the same time, can also maximize the recovery of useful components in the gas to avoid waste of resources. Among them, the thermostatic heater 43 adopts existing technology, for example, a thermostatic heater with a model of HAD / BHW-09C can be used;

[0050] The catalyst bed 41 is filled with a VW-Ti type catalyst. The synergistic effect of V, W and Ti can provide multiple active sites, which can effectively adsorb nitrogen oxide molecules and reduce the activation energy of the nitrogen oxide reduction reaction. The nitrogen oxides can be quickly and effectively reduced to nitrogen gas, thereby improving the conversion efficiency of nitrogen oxides, thereby more effectively reducing the nitrogen oxide content in the gas.

[0051] Example 2: This example discloses a low-energy dual-carbon capture system based on membrane separation technology. A low-energy dual-carbon capture system based on membrane separation technology according to Example 1 includes the following steps:

[0052] S1, the air to be treated enters the first CO 2 When in the capture unit 2, first, the temperature is lowered by the first heat exchanger 10, so that the water vapor in the air to be treated is easier to condense into liquid water in the subsequent condensation process, and then the temperature is gradually lowered by each condenser 110 connected in series in sequence, and the temperature of the air condensed by the previous condenser 110 is monitored in real time by the temperature sensor 112 between two adjacent condensers 110. According to the temperature feedback, the flow rate of the air flowing into the next condenser 110 can be adjusted by the flow regulating valve 111, and the condensed air is separated into steam and water by the steam-water separator 12;

[0053] S2, the gas flowing out of the steam-water separator 12 will simultaneously enter the CO 2 In the membrane separator 20 and the absorption tower 21, CO 2 Membrane separator 20 for CO in air 2 Membrane separation is performed, and the captured CO is stored in the first storage tank 200.2 The separated gas enters the first CO capture unit 3, where the CO in the air is absorbed by the adsorbent in the absorption tower 21. 2 Adsorption capture and formation of liquid CO 2 The separated gas enters the first CO capture unit 3, and the captured liquid CO 2 After being discharged and cooled by heat exchange in the second heat exchanger 212, it is filtered by the filter 211 and stored in the second storage tank 213;

[0054] S3, after the first CO 2 Before the gas processed by the capture unit 2 flows into the first CO capture unit 3, it is mixed by the gas premixing box 32, and the processed gas enters the second shell 332 through the second gas inlet 330, and the CO therein is captured by the CO separation membrane 31, and the captured CO is stored in the CO storage tank 34, and the separated gas is discharged to the nitrogen oxide reaction unit 4 through the second gas outlet 331;

[0055] S4, when the gas is discharged into the nitrogen oxide reaction unit 4 through the second gas outlet 331, it first enters the reactor body 40, and the catalyst on the catalyst bed 41 adsorbs the nitrogen oxides in the gas and reduces them to nitrogen, and then passes through the N 2 The storage tank 42 stores nitrogen. At the same time, the interior of the reactor body 40 is heated by the constant temperature heater 43, and the remaining gas is stored in the tail gas storage tank 50;

[0056] S5, the CO stored in the CO storage tank 34 is passed through the gas premixing box 32, and then passed into the second CO capture unit 30 to repeat the CO capture process, and the remaining gas after separation is passed into the tail gas storage tank 50 for storage, and the gaseous CO stored in the first storage tank 200 is 2 The second CO 2 Residual CO is collected in the capture unit 5 2 Repeated capture, and the captured CO 2 Temporarily store, the separated gas is passed into the tail gas storage tank 50 for storage.

[0057] Embodiment 3: This embodiment differs from Embodiment 1 in that:

[0058] like Figure 3 , 4 , 5, CO 2 The membrane separator 20 includes a first shell 23 with a first air inlet 230 and a first air outlet 231 on both sides, a flow divider 24 disposed in the first shell 23 and close to the first air inlet 230, and a CO 2The separation membrane 6 is disposed in the first housing 23 and connected to the diverter plate 24. 2 The separation membrane 6 is composed of 9 tubular capture membranes 25 connected to the diverter plate 24 through 9 inlet branches 250 and provided with inlet valves 251 at the connection points. A reflux plate 253 is connected to each tubular capture membrane 25 on the side opposite to the diverter plate 24 through 9 outlet branches 252. A CO 2 Compared with a single flat membrane structure, the nine tubular capture membranes 25 can provide a larger membrane area in a limited space, thereby improving CO 2 Separation efficiency with other gases, more CO 2 The molecules have the opportunity to contact with the surface of the tubular capture membrane 25 and pass through the tubular capture membrane 25 for separation. If a tubular capture membrane 25 or an air inlet valve 251 fails, it can be relatively easy to locate and replace without affecting the normal operation of other parts of the entire membrane separator 20, thereby reducing maintenance costs and difficulties. Among them, the air inlet valve 251 adopts existing technology, for example, an air inlet valve of model RH-50E can be used;

[0059] The tubular capture membrane 25 includes four first spiral capture membrane bodies 254 connected to each inlet branch pipe 250 in a one-to-one correspondence, and four second spiral capture membrane bodies 255 uniformly distributed around each first spiral capture membrane body 254 along the circumferential direction. The four second spiral capture membrane bodies 255 around each first spiral capture membrane body 254 are connected to the reflux disk 253 at one end, and connected to the inlet end of the first spiral capture membrane body 254 at the other end, and a one-way valve 256 is provided at the connection. Each outlet branch pipe 252 is provided with an outlet valve 2520. The gas enters each tubular capture membrane 25 from left to right through the inlet branch pipe 250. At this time, the inlet valve 251 at the inlet branch pipe 250 and the outlet valve 2520 on the corresponding outlet branch pipe 252 are closed, and the gas first passes through each first spiral capture membrane body 254. Due to its spiral structure, the contact area between the gas and the first spiral capture membrane body 254 is increased, thereby improving CO 2 The gas flows from the tubular capture membrane 25 into the reflux plate 253, and flows back to the first spiral capture membrane body 254 from right to left through each second spiral capture membrane body 255 outside the first spiral capture membrane body 254 for repeated treatment, which can ensure that the CO in the gas 2 After the capture is completed, the gas is discharged by opening the outlet valve 2520 on the outlet branch pipe 252. Since a one-way valve 256 is provided at the connection between the second spiral capture membrane body 255 and the inlet end of the first spiral capture membrane body 254, the gas near the end of the diverter plate 24 can only flow from the second spiral capture membrane body 255 into the first spiral capture membrane body 254, and cannot flow back, which greatly improves the overall CO 2Capture rate, wherein the one-way valve 256 and the outlet valve 2520 both adopt existing technologies, for example, the one-way valve 256 can adopt a one-way valve of model H44H-16C, and the outlet valve 2520 can adopt an existing disc valve, and the first spiral capture membrane body 254 is a spiral structure, and the spiral shape helps to increase the contact area and contact time between the gas and the membrane. When the gas flows along the spiral path, the gas molecules have more opportunities to interact with the membrane surface. The material has a selective adsorption or filtration function, for example, it may be made of a high molecular polymer, and the second spiral capture membrane body 255 is the same.

[0060] Embodiment 4: This embodiment differs from Embodiment 2 in that:

[0061] In step S2, CO 2 Membrane separator 20 for CO in air 2 When performing membrane separation and capture, air first enters the diverter plate 24 through the first air inlet 230, and the diverter plate 24 evenly distributes the incoming air, and then enters the corresponding tubular capture membrane 25 through each air inlet branch pipe 250. 2 can flow out of the capture membrane 25 and pass through the CO 2 The discharge pipe 232 discharges into the first storage tank 200, and the remaining gas after separation flows into the reflux disk 253 through the outlet branch pipe 252 and is discharged through the first outlet port 231. If a tubular capture membrane 25 or an inlet valve 251 fails, it can be relatively easy to locate and replace;

[0062] In step S2, the gas enters each tubular capture membrane 25 from left to right through the inlet branch pipe 250. At this time, the inlet valve 251 at the inlet branch pipe 250 and the outlet valve 2520 on the corresponding outlet branch pipe 252 are closed, and the gas first passes through each first spiral capture membrane body 254, and the gas flows from the tubular capture membrane 25 into the reflux plate 253, and then flows back to the first spiral capture membrane body 254 from right to left through each second spiral capture membrane body 255 outside the first spiral capture membrane body 254 for repeated treatment, which can ensure that the CO in the gas is 2 After being fully captured, the gas is discharged by opening the outlet valve 2520 on the outlet branch pipe 252. Since a one-way valve 256 is provided at the connection between the second spiral capture membrane body 255 and the air inlet end of the first spiral capture membrane body 254, the gas near the diverter plate 24 can only flow from the second spiral capture membrane body 255 into the first spiral capture membrane body 254, and cannot flow back.

Claims

1. A low-energy dual carbon capture system based on membrane separation technology, characterized in that: It comprises a condensation and water removal unit (1), a first CO2 capture unit (2) for capturing CO2 in the gas, a first CO capture unit (3) for capturing CO in the gas, and a nitrogen oxide reaction unit (4) which are sequentially connected along the gas flow direction; The first CO2 capture unit (2) has two outlets, one of which is connected to the second CO2 capture unit (5), and the other is connected to the first CO capture unit (3); A CO2 separation membrane (6) is provided in the first CO2 capture unit (2) and the second CO2 capture unit (5), and a pressure regulating device (22) is connected to the first CO2 capture unit (2) and the second CO2 capture unit (5); The first CO capture unit (3) has two outlets, the first outlet is connected to the second CO capture unit (30), and the second outlet is connected to the nitrogen oxide reaction unit (4); A CO separation membrane (31) is provided in the first CO capture unit (3) and the second CO capture unit (30), and a gas premixing box (32) is connected to the inlet of each of the first CO capture unit (3) and the second CO capture unit (30); The second CO capture unit (30), the nitrogen oxide reaction unit (4) and the second CO2 capture unit (5) are all connected to an exhaust gas storage tank (50).

2. A low-energy dual carbon capture system based on membrane separation technology according to claim 1, characterized in that: The condensation and dehydration unit (1) comprises a first heat exchanger (10), a multi-stage condensation component (11) connected to the first heat exchanger (10), and a steam-water separator (12) for connecting the multi-stage condensation component (11) and the first CO2 capture unit (2); the multi-stage condensation component (11) is composed of a plurality of condensers (110) connected in series, and a flow regulating valve (111) and a temperature sensor (112) are provided between two adjacent condensers (110).

3. The low-energy dual carbon capture system based on membrane separation technology according to claim 1 is characterized in that: The first CO2 capture unit (2) comprises a CO2 membrane separator (20) and an absorption tower (21) both connected to the condensation and water removal unit (1) and in parallel, the CO2 membrane separator (20) being connected to a first storage tank (200), the absorption tower (21) being provided with a heater (210), the side wall of the absorption tower (21) being connected to a filter (211) and a second heat exchanger (212) being provided at the connection, the filter (211) being connected to a second storage tank (213), and the second CO2 capture unit (5) having the same structure as the first CO2 capture unit (2).

4. A low-energy dual carbon capture system based on membrane separation technology according to claim 3, characterized in that: The CO2 membrane separator (20) comprises a first shell (23) having a first air inlet (230) and a first air outlet (231) on both sides, and a diverter plate (24) arranged in the first shell (23) and close to the first air inlet (230). The CO2 separation membrane (6) is arranged in the first shell (23) and connected to the diverter plate (24). The CO2 separation membrane (6) is composed of a plurality of tubular capture membranes (25) connected to the diverter plate (24) through a plurality of air inlet branch pipes (250) and respectively provided with air inlet valves (251) at the connection points. A reflux plate (253) is connected to each tubular capture membrane (25) on the side opposite to the diverter plate (24) through a plurality of air outlet branch pipes (252). A CO2 discharge pipe (232) is provided at the bottom end of the first shell (23).

5. A low-energy dual carbon capture system based on membrane separation technology according to claim 4, characterized in that: The tubular capture membrane (25) comprises a plurality of first spiral capture membrane bodies (254) connected one-to-one with each of the intake branch pipes (250), and a plurality of second spiral capture membrane bodies (255) uniformly distributed along the circumferential direction on the periphery of each first spiral capture membrane body (254). The plurality of second spiral capture membrane bodies (255) on the periphery of each first spiral capture membrane body (254) are connected to the reflux disk (253) at one end and to the intake end of the first spiral capture membrane body (254) at the other end, and a one-way valve (256) is provided at the connection.

6. The low-energy dual carbon capture system based on membrane separation technology according to claim 1, characterized in that: There are two pressure regulating devices (22), which are respectively arranged at the inlet of the first CO2 capture unit (2) and the inlet of the second CO2 capture unit (5), and the pressure regulating device (22) comprises a pressure sensor (220) and a regulating valve (221).

7. The low-energy dual carbon capture system based on membrane separation technology according to claim 1, characterized in that: The first CO2 capture unit (3) comprises a CO2 membrane separator (33) and a CO2 storage tank (34) connected to the first CO2 capture unit (2); the CO2 membrane separator (33) comprises a second shell (332) having a second air inlet (330) and a second air outlet (331) on both sides thereof, and the CO2 separation membrane (31) arranged in the second shell (332); the CO2 storage tank (34) is connected to the bottom end of the second shell (332); and the second CO2 capture unit (30) has the same structure as the first CO2 capture unit (3).

8. The low-energy dual carbon capture system based on membrane separation technology according to claim 1, characterized in that: The nitrogen oxide reaction unit (4) comprises a reactor body (40), a catalyst bed (41) arranged in the reactor body (40), an N2 storage tank (42) connected to the reactor body (40), and a constant temperature heater (43) arranged in the reactor body (40).

9. A low-energy dual carbon capture system based on membrane separation technology according to claim 8, characterized in that: The catalyst bed (41) is filled with a VW-Ti type catalyst.

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