CO2 direct air trapping system and method for improving partial pressure of CO2

Abstract

The invention discloses a CO2 direct air trapping system and method for improving CO2 partial pressure. The system comprises a first air pump, a second air pump, a microbial fuel cell device, a CO2 trapping device, a rich liquid desorption unit and a CO2 storage unit, the microbial fuel cell device comprises a reactor box body, a proton exchange membrane, a lead and an external circuit; the first air pump is arranged outside the microbial fuel cell device and pumps ambient air into the cathode chamber; a jacket wrapping the reactor box body is arranged outside the reactor box body; the CO2 trapping device is a closed box body, and a liquid inlet, a liquid outlet, a gas inlet and a gas outlet are formed in the CO2 trapping device; a gas outlet of a cathode chamber of the microbial fuel cell device is connected with a gas inlet of the CO2 trapping device through a pipeline, and a second gas pump is arranged on the pipeline; the pregnant solution desorption unit comprises a battery waste heat heating device and an electric heating desorber; the CO2 storage unit includes a CO2 compressor and a CO2 reservoir.

Description

Technical Field

[0001] The present invention relates to the technical field of direct air capture of carbon dioxide, and in particular to a method for improving CO 2 Partial pressure of CO 2 Direct air capture systems and methods. Background Art

[0002] Carbon dioxide capture, utilization and storage (CCUS) technology is of great significance for achieving carbon neutrality and is considered to be the most economical and feasible method to reduce greenhouse gas emissions and mitigate global warming on a large scale in the future. The large-scale application of this technology will help to significantly reduce carbon dioxide emissions in the short term and effectively alleviate the greenhouse effect. CCUS is divided into capture, transportation, utilization and storage according to the technical process. 2 Capture is the process of converting CO 2 The process of separation from industry, energy activities or the atmosphere.

[0003] The main carbon dioxide capture technologies currently include chemical absorption, physical absorption, membrane separation and adsorption.

[0004] (1) Chemical absorption method: chemical reagents are used to react with carbon dioxide to form salts (such as carbonates or bicarbonates), and then the carbon dioxide is released and collected by heating or reducing pressure; commonly used chemical absorbents include amines, such as ethylenediamine and methanolamine. It is suitable for low-concentration carbon dioxide environments, such as flue gas treatment in coal-fired power plants, cement plants, and steel plants. The chemical absorption method has the disadvantages of high energy consumption in the capture process, low absorbent circulation efficiency, and high CO 2 High recycling cost, CO 2 The capture equipment is bulky and has little operational flexibility.

[0005] (2) Physical absorption method: The acid gas is absorbed by an organic solvent under pressurized conditions to separate and remove the acid gas components. The solvent is regenerated by reducing the pressure, and the regeneration energy required is relatively small. The physical absorption method is suitable for CO 2 At higher concentrations, CO 2 Separation, such as CO in IGCC 2 Separation; it is carried out at a higher operating pressure and is not suitable for CO in tail gas 2 separation.

[0006] (3) Membrane separation method: The membrane separation method uses the different permeability of thin films made of specific materials to separate gases. Membrane materials are divided into organic polymer membranes and inorganic membranes. They are suitable for occasions where high-purity carbon dioxide is required. The disadvantage is that the CO 2 The separation rate is low, and it is difficult to obtain high-purity CO 2 ,To achieve a certain emission reduction, a multi-stage separation process is often required.

[0007] (4) Adsorption method: It is a method in which an adsorbent absorbs CO under certain conditions. 2 Selective adsorption is performed, and then CO is recovered under recovery conditions. 2 Desorption to separate CO 2 The commonly used adsorbents are: natural zeolite, molecular sieve, activated alumina, silica gel, "molecular basket" adsorbent, ion compound adsorbent, carbon-based adsorbent, etc. Adsorption separation of CO 2 The main disadvantages are: low separation rate; high CO 2 There are few selective adsorbents; when used in the power industry, adsorption is cost-prohibitive.

[0008] Direct air capture (DAC) is a technology that can capture carbon dioxide from the atmosphere. It is an important CCUS technology and an indispensable negative emission technology. 2 Direct air capture technologies include: solid adsorption method and solution adsorption method. Solid adsorption method is a method that can effectively adsorb carbon dioxide from the air under normal temperature and pressure conditions. It has the advantages of high adsorption efficiency, good material stability, and low operating cost. However, solid adsorption method has the disadvantages of limited adsorption capacity, complex regeneration process, and high equipment cost. The solution absorption method mainly uses alkaline hydroxide solutions (such as NaOH, KOH and Ca(OH) 2 ) to practice air decarbonization. These solutions have strong carbon dioxide binding ability, low volatility and relatively mature processes, making them the main choice of air capture absorbent. However, the alkaline solution absorption method has the disadvantage of being highly corrosive to equipment materials, especially during long-term operation, the corrosion problem will significantly increase the cost of equipment maintenance and replacement. 2 Among them, the most commonly used method is the amine solution absorption method, because the amine solution absorption method has the advantages of high absorption efficiency, high reaction speed and strong regeneration ability, but due to the CO in the air 2 The partial pressure of CO is low. If the amine solution absorption method is used in direct air capture, the problem of chemical solvent evaporation loss will occur due to the need to process a large amount of air. 2 When direct air capture is performed, CO 2 The proportion of amine solution is only 0.04%, which makes the absorption efficiency and utilization of amine solution in the capture process not high. In addition, when desorbing rich solution, in the traditional rich solution desorption method, a large amount of energy needs to be input into the system for desorption, which increases the economic cost of the entire system.

[0009] Microbial fuel cell (MFC) is a device that uses microorganisms to directly convert chemical energy in organic matter into electrical energy. Its basic working principle is: in the anaerobic environment of the anode chamber, organic matter is decomposed by microorganisms and releases electrons and protons. Electrons are effectively transferred between the biological components and the anode by appropriate electron transfer mediators, and are transferred to the cathode through an external circuit to form a current, while protons are transferred to the cathode through a proton exchange membrane. The oxidant (usually oxygen) obtains electrons at the cathode and is reduced and combined with protons to form water. According to the electron transfer mode, microbial fuel cells can be divided into direct and indirect microbial fuel cells. The so-called direct means that while the fuel is oxidized on the electrode, the electrons are directly transferred from the fuel molecules to the electrode, and then the biological catalyst directly catalyzes the reaction on the electrode surface. This reaction is called a redox reaction in chemistry; if the fuel reacts in the electrolyte or other places, the battery in which the electrons are transferred to the electrode through the redox mediator is called an indirect microbial fuel cell. According to whether the electron transfer mediator needs to be added to the battery, it can be divided into mediator-containing and non-mediator microbial fuel cells. Microbial fuel cells usually include proton exchange membranes, anodes, cathodes, anode chambers, cathode chambers, wires, and external circuits. The external circuit refers to the current path outside the power source, that is, the path from the positive electrode of the power source, through the wires, loads and other components, and finally back to the negative electrode of the power source. The external circuit is usually composed of wires, switches, loads, etc. It is the place where electrical energy is converted into other forms of energy.

[0010] There are currently no reports on combining microbial fuel cells with direct air capture of carbon dioxide. Summary of the invention

[0011] The purpose of the present invention is to provide a method for improving CO 2 Partial pressure of CO 2 Direct air capture systems and methods.

[0012] In order to achieve its purpose, the present invention adopts the following technical solution:

[0013] The first aspect of the present invention provides a method for increasing CO 2 Partial pressure of CO 2 A direct air capture system comprising a first air pump, a second air pump, a microbial fuel cell device, a CO 2 Capture device, rich liquid desorption unit and CO 2 Storage unit;

[0014] The microbial fuel cell device comprises a reactor box, a proton exchange membrane, a wire and an external circuit; the proton exchange membrane is vertically arranged in the reactor box, and the interior of the reactor box is divided into an anode chamber and a cathode chamber, the anode chamber is provided with an anode, the cathode chamber is provided with a cathode, the two ends of the wire are respectively connected to the anode and the cathode, and the external circuit is arranged outside the reactor box and connected to the wire; the first air pump is arranged outside the microbial fuel cell device, connected to the cathode chamber through an air inlet pipe, and pumps ambient air into the cathode chamber; a jacket that wraps the reactor box is arranged outside the reactor box, and an air outlet is arranged on the anode chamber; an air inlet and an air outlet are arranged on the cathode chamber;

[0015] The CO 2 The capture device is a closed box, CO 2 The capture device is provided with a liquid inlet, a liquid outlet, an air inlet, and an air outlet; the air outlet of the cathode chamber of the microbial fuel cell device is connected to the CO 2 The air inlet of the capture device is connected via a pipeline, and the second air pump is arranged on the pipeline;

[0016] The rich liquid desorption unit comprises a battery waste heat heating device and an electric heating desorber. The battery waste heat heating device is the jacket arranged outside the reactor box. The jacket is provided with a liquid inlet and a liquid outlet. The liquid inlet of the jacket is in contact with the CO 2 The liquid outlet of the capture device is connected by a pipeline, and the jacket is used to circulate and absorb the CO 2 The main body of the electric heating desorber is an electric heater, the liquid outlet of the jacket is connected to the liquid inlet of the electric heater through a pipeline, and the rich liquid in the jacket is input into the electric heater; the electric heater is electrically connected to the external circuit of the microbial fuel cell device to obtain electric energy for heating; an air outlet is provided on the main body of the electric heating desorber; the liquid outlet of the electric heater is connected to the CO 2 The liquid inlet of the capture device is connected by a pipeline;

[0017] The CO 2 The storage unit includes CO 2 Compressor and CO 2 The gas outlet of the electric heating desorber and the gas outlet of the anode chamber are connected to the CO 2 The compressor is connected by pipeline, CO 2 Compressor and CO 2 The storage tanks are connected by pipes.

[0018] Preferably, the CO 2 The liquid inlet of the capture device 3 is also connected to a liquid replenishing tube for replenishing new absorption liquid from the outside.

[0019] Preferably, the CO 2The capture device contains an absorption liquid, which is selected from a single amine absorption liquid, a mixed amine absorption liquid and an ion solution.

[0020] Preferably, the single amine absorption liquid is selected from monoethanolamine MEA, diethanolamine DEA, and methyldiethanolamine MDEA.

[0021] Preferably, all the pipelines are provided with switch valves.

[0022] Preferably, pipes for circulating liquid are provided with water pumps for adjusting flow rate and flow velocity.

[0023] Preferably, the material of the cathode is selected from graphite, carbon cloth, carbon paper, and carbon-supported platinum material, and the material of the anode is selected from carbon paper, carbon cloth, graphite rod, graphite fiber brush, activated carbon, and carbon nanotubes.

[0024] Preferably, an oxygen sensor is provided in the cathode chamber for monitoring the oxygen concentration in the cathode chamber.

[0025] A second aspect of the present invention provides a method for increasing CO 2 Partial pressure of CO 2 Direct air capture method, using any of the above system capture, including the following steps:

[0026] Step 1: Increase CO 2 Partial Pressure

[0027] Water containing organic matter is introduced into the anode chamber of the microbial fuel cell device. 2 CO is injected into the capture device 2 The first air pump is turned on to pump air into the cathode chamber of the microbial fuel cell device. The oxygen in the air participates in the reaction in the cathode chamber and is consumed. The CO in the deoxygenated air 2 The partial pressure is increased by pumping CO in through the second gas pump. 2 In the capture device;

[0028] Step 2: CO 2 Capture adsorption

[0029] Increased CO 2 The partial pressure of air entering the CO 2 The CO in the capture device 2 Absorption liquid adsorption, CO 2 The absorbed liquid becomes rich liquid;

[0030] Step 3: CO 2 Thermal Desorption

[0031] Rich liquid from CO 2The capture device enters the jacket outside the reactor box of the microbial fuel cell device. The heat generated by the reaction inside the reactor box heats the rich liquid in the jacket. The heated rich liquid enters the electric heating desorber and is further heated to make CO 2 Thermal desorption, CO 2 Gas is desorbed from the rich liquid;

[0032] Step 4: CO 2 store

[0033] CO produced by the reaction in the anode chamber of the microbial fuel cell device 2 The gas enters the CO 2 The CO2 is desorbed from the rich liquid in the compressor and the electric heating desorber 2 Gas also enters the CO through the pipeline 2 Compressor, CO 2 The compressor converts CO 2 The gas is compressed and transported into CO 2 Stored in storage.

[0034] The water containing organic matter in step 1 is organic wastewater containing sugars, fats and proteins.

[0035] The beneficial effects of the present invention are:

[0036] (1) Absorbent to CO 2 During absorption, CO 2 The proportion of oxygen in the ambient air increased from 0.04% to 0.0506% after deoxygenation, an increase of nearly 1.3 times, which improved the absorption efficiency and utilization rate of the absorption liquid.

[0037] (2) The anode feed of the microbial fuel cell is wastewater, and the cathode feed is air, which can treat the wastewater while capturing CO in the air. 2 , reducing the economic cost of wastewater treatment.

[0038] (3) In the rich liquid desorption device, the heat generated by the internal reaction of the microbial fuel cell device is used to preliminarily heat the rich liquid. The temperature of the reactor box of the microbial fuel cell device is 30℃~40℃, while the optimal operating temperature of the microbial fuel cell is 20℃~35℃. The heat generated in the reactor box is used to heat the rich liquid. On the one hand, the temperature of the reactor box is reduced to keep the internal reaction temperature at the optimal temperature. On the other hand, the temperature of the rich liquid is increased to reduce the energy consumption for further heating and desorption of the rich liquid.

[0039] (4) The electricity generated by the microbial fuel cell device is used to heat the rich liquid through an electric heater so that the rich liquid reaches the target desorption temperature. No additional energy is required from the outside, which greatly reduces the energy consumption of rich liquid desorption.

[0040] The system of the present invention can simultaneously realize wastewater treatment and CO 2 Direct air capture, microbial fuel cell device for wastewater treatment to CO 2 Direct air capture units provide heat, significantly reducing CO 2 Energy consumption for direct air capture, while CO 2 In the direct air capture process, the rich liquid cools the reactor box of the microbial fuel cell device and promotes the reaction therein. The two promote each other and reduce energy consumption and economic costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 CO of the present invention 2 Schematic diagram of the structure of a direct air capture system.

[0042] Figure 2 CO of the present invention 2 Schematic diagram of the direct air capture method.

[0043] in, Figure 1 The elements or structures indicated by the reference numerals are:

[0044] A first air pump 1, a second air pump 6;

[0045] Reactor housing 21, proton exchange membrane 22, wire 23, external circuit 24, anode 25, cathode 26;

[0046] CO 2 Capture device 3;

[0047] Jacket 41, electric heating desorber 42;

[0048] CO 2 Compressor 51, CO 2 Storage 52. DETAILED DESCRIPTION

[0049] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention, but the present invention is not limited thereto. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0050] The experimental methods in the following examples are conventional methods unless otherwise specified.

[0051] like Figure 1 The present invention is a method for improving CO 2 Partial pressure of CO 2The direct air capture system mainly comprises a first air pump 1, a second air pump 6, a microbial fuel cell device, a CO 2 Capture device 3, rich liquid desorption unit and CO 2 Storage unit composition.

[0052] The microbial fuel cell device comprises a reactor box 21, a proton exchange membrane 22, a wire 23 and an external circuit 24; the proton exchange membrane 22 is vertically arranged in the reactor box 21, and the interior of the reactor box 21 is divided into an anode chamber and a cathode chamber, an anode chamber is provided with an anode 25, and a cathode chamber is provided with a cathode 26, two ends of the wire 23 are respectively connected to the anode 25 and the cathode 26, and the external circuit 24 is arranged outside the reactor box 21 and connected to the wire 23; the first air pump 1 is arranged outside the microbial fuel cell device, connected to the cathode chamber through an air inlet pipe, and pumps ambient air into the cathode chamber; a jacket 41 wrapping the reactor box is arranged outside the reactor box 21, and an air outlet is arranged on the anode chamber; and an air inlet and an air outlet are arranged on the cathode chamber.

[0053] CO 2 The capture device 3 is a closed box, CO 2 The capture device 3 is provided with a liquid inlet, a liquid outlet, an air inlet, and an air outlet; the air outlet of the cathode chamber of the microbial fuel cell device is connected to the CO 2 The air inlet of the capture device 3 is connected via a pipeline, and a second air pump 6 is arranged on the pipeline. 2 The collecting device 3 contains the absorption liquid.

[0054] The rich liquid desorption unit includes a battery waste heat heating device and an electric heating desorber 42. The battery waste heat heating device is a jacket 41 arranged outside the reactor box 21. The jacket 41 is provided with a liquid inlet and a liquid outlet. The liquid inlet of the jacket 41 is connected to the CO 2 The liquid outlet of the capture device 3 is connected by a pipeline, and the jacket 41 is used to circulate the absorbed CO 2 The main body of the electric heating desorber 42 is an electric heater (for example, an electric water heater can be directly used), the liquid outlet of the jacket 41 is connected to the liquid inlet of the electric heater through a pipeline, and the rich liquid in the jacket 41 is input into the electric heater; the electric heater is electrically connected to the external circuit 24 of the microbial fuel cell device to obtain electric energy for heating; an air outlet is provided on the main body of the electric heating desorber 42; the liquid outlet of the electric heater is connected to the CO 2 The liquid inlet of the capture device 3 is connected via a pipeline.

[0055] CO 2 The storage unit includes CO 2 Compressor 51 and CO 2 The gas outlet of the electric heating desorber 42 and the gas outlet of the anode chamber are connected to the CO 2The compressor 51 is connected via a pipeline, CO 2 Compressor 51 and CO 2 The storages 52 are connected by pipelines.

[0056] In some embodiments, CO 2 The liquid inlet of the capture device 3 is also connected to a liquid replenishing pipe for replenishing new absorption liquid from the outside. As the number of system operation cycles increases, the absorption efficiency of the absorption liquid will decrease and there will also be consumption, so new absorption liquid is added regularly to ensure the system operation efficiency.

[0057] In some embodiments, CO 2 The absorption liquid in the capture device 3 is selected from a single amine absorption liquid, a mixed amine absorption liquid and an ion solution.

[0058] In some embodiments, the single amine absorbent is selected from monoethanolamine MEA, diethanolamine DEA, methyldiethanolamine MDEA.

[0059] In some embodiments, all pipelines are provided with switch valves for controlling the flow of gas or liquid.

[0060] In some embodiments, pipes for circulating liquid are provided with water pumps for adjusting the flow rate and flow velocity.

[0061] In some embodiments, the material of cathode 26 is selected from graphite, carbon cloth, carbon paper, platinum-containing (carbon-supported platinum) and other materials, and the material of anode 25 is selected from carbon paper, carbon cloth, graphite rod, graphite fiber brush, activated carbon, carbon nanotubes and the like.

[0062] In some embodiments, an oxygen sensor is disposed in the cathode chamber to monitor the oxygen concentration in the cathode chamber.

[0063] The working principle of the system of the present invention (its working principle and process are as follows) Figure 2 shown) is:

[0064] In a microbial fuel cell device, organic wastewater is introduced into the anode chamber of the microbial fuel cell device, which is filled with electroactive microorganisms attached to the anode surface. These microorganisms metabolize the organic matter in the wastewater (which is rich in organic matter, such as sugars, fats, proteins and other pollutants), breaking it down into simpler substances while releasing electrons (e - ) and protons (H + The released electrons are transferred to the anode surface through the electron transport chain outside the microorganism and flow to the cathode through the external circuit. This process generates current. The reaction at the anode is as follows: organic matter → CO 2 +H + +e -At the same time, protons migrate from the anode chamber to the cathode chamber through the proton exchange membrane. In the cathode chamber, electrons interact with protons from the anode chamber and air 1 (including 78.08% N 2 ,20.95%O 2 ,0.04%CO 2 ) undergoes a reduction reaction. The cathode reaction is as follows: 2 +4H + +4e - →2H 2 O. Through the above reaction in the microbial fuel cell device, the organic matter in the wastewater is gradually decomposed into harmless CO 2 and water, thereby purifying wastewater. At the same time, it consumes oxygen in the air 1, achieving the goal of increasing CO in the air. 2 In addition, the metabolic activity of microorganisms provides a stable flow of electrons for microbial fuel cells, thereby generating electricity.

[0065] In CO 2 In the capture device, the absorption liquid enters the CO 2 In the capture device, the air 2 (98.77% N 2 ,0%O 2 ,0.0506%CO 2 ) CO is pumped in by the second gas pump 2 In the capture device, the absorbent reacts with the CO in the air 2 2 Adsorption capture, CO 2 The captured air 3 (98.82% N 2 ,0%O 2 ,0%CO 2 ) and absorb CO 2 The rich liquid is discharged through the gas outlet and the liquid outlet respectively. 2 The reaction in the capture device completes the CO 2 of capture.

[0066] In the rich liquid desorption unit, the reactor box of the microbial fuel cell device generates heat due to the reaction inside it, which makes the shell of the reactor box itself hot. The rich liquid flows in the jacket outside the reactor box. The rich liquid is used as a heat exchange medium to exchange heat with the reactor box. The rich liquid absorbs heat from the shell of the reactor box, so that the rich liquid is initially heated, while the reactor box is cooled (the temperature of the waste heat of the microbial fuel cell is 30℃~40℃, and the optimal operating temperature of the microbial fuel cell is 20℃~35℃), which is conducive to the reaction in the reactor box. After the preliminary heating, the rich liquid enters the electric heating desorber. The electric energy of the electric heating desorber comes from the electric energy generated by the microbial fuel cell device. The electric heating desorber further heats the rich liquid to achieve CO 2 Desorption temperature, CO in rich solution 2 Desorption, the absorption liquid is desorbed to become lean liquid, and the lean liquid re-enters the CO 2 The capture device performs an adsorption-desorption cycle to continuously capture CO in the air 2 .

[0067] In CO 2 In the storage unit, CO generated from the anode chamber of the microbial fuel cell device 2 and CO from the rich liquid desorption unit 2 First, introduce CO 2 The compressor boosts the pressure and then enters the CO 2 Stored in storage.

[0068] Example 2

[0069] The present invention is a method for improving CO 2 Partial pressure of CO 2 Direct air capture method, using any of the CO 2 Direct air capture system capture includes the following steps:

[0070] Step 1: Increase CO 2 Partial Pressure

[0071] Wastewater containing organic matter (containing sugars, fats, proteins, etc.) is introduced into the anode chamber of the microbial fuel cell device. 2 CO is injected into the capture device 2 The first air pump is turned on to pump air into the cathode chamber of the microbial fuel cell device. The oxygen in the air participates in the reaction in the cathode chamber and is consumed. The CO in the deoxygenated air 2 The partial pressure is increased by pumping CO in through the second gas pump. 2The oxygen concentration in the cathode chamber can be monitored by the oxygen sensor in the cathode chamber. When the oxygen concentration in the cathode chamber is lower than 1%, the first air pump is turned off and the second air pump is turned on to pump the deoxygenated air in the cathode chamber into the CO 2 Capture device.

[0072] Step 2: CO 2 Capture adsorption

[0073] Increased CO 2 The partial pressure of air entering the CO 2 The CO in the capture device 2 Absorption liquid adsorption, CO 2 The absorbing liquid becomes rich liquid.

[0074] Step 3: CO 2 Thermal Desorption

[0075] Rich liquid from CO 2 The capture device enters the jacket outside the reactor box of the microbial fuel cell device. The heat generated by the reaction inside the reactor box heats the rich liquid in the jacket. The heated rich liquid enters the electric heating desorber and is further heated to make CO 2 Thermal desorption, CO 2 The gas is desorbed from the rich liquid.

[0076] Step 4: CO 2 store

[0077] CO produced by the reaction in the anode chamber of the microbial fuel cell device 2 The gas enters the CO 2 The CO2 is desorbed from the rich liquid in the compressor and the electric heating desorber 2 Gas also enters the CO through the pipeline 2 Compressor, CO 2 The compressor converts CO 2 The gas is compressed and transported into CO 2 Stored in storage.

Claims

1. A CO2 direct air capture system for increasing CO2 partial pressure, characterized in that: It includes a first air pump, a second air pump, a microbial fuel cell device, a CO2 capture device, a rich liquid desorption unit and a CO2 storage unit; The microbial fuel cell device comprises a reactor box, a proton exchange membrane, a wire and an external circuit; the proton exchange membrane is vertically arranged in the reactor box, and the interior of the reactor box is divided into an anode chamber and a cathode chamber, the anode chamber is provided with an anode, the cathode chamber is provided with a cathode, the two ends of the wire are respectively connected to the anode and the cathode, and the external circuit is arranged outside the reactor box and connected to the wire; the first air pump is arranged outside the microbial fuel cell device, connected to the cathode chamber through an air inlet pipe, and pumps ambient air into the cathode chamber; a jacket that wraps the reactor box is arranged outside the reactor box, and an air outlet is arranged on the anode chamber; an air inlet and an air outlet are arranged on the cathode chamber; The CO2 capture device is a sealed box, and is provided with a liquid inlet, a liquid outlet, an air inlet, and an air outlet; the air outlet of the cathode chamber of the microbial fuel cell device is connected to the air inlet of the CO2 capture device through a pipeline, and the second air pump is provided on the pipeline; The rich liquid desorption unit comprises a battery waste heat heating device and an electric heating desorber. The battery waste heat heating device is the jacket arranged outside the reactor box. The jacket is provided with a liquid inlet and a liquid outlet. The liquid inlet of the jacket is connected to the liquid outlet of the CO2 capture device through a pipeline. The jacket is used to circulate the rich liquid after absorbing CO2. The main body of the electric heating desorber is an electric heater. The liquid outlet of the jacket is connected to the liquid inlet of the electric heater through a pipeline, and the rich liquid in the jacket is input into the electric heater. The electric heater is electrically connected to the external circuit of the microbial fuel cell device to obtain electrical energy for heating. The main body of the electric heating desorber is provided with an air outlet. The liquid outlet of the electric heater is connected to the liquid inlet of the CO2 capture device through a pipeline. The CO2 storage unit includes a CO2 compressor and a CO2 storage; the gas outlet of the electric heating desorber and the gas outlet of the anode chamber are connected to the CO2 compressor through a pipeline, and the CO2 compressor and the CO2 storage are connected through a pipeline.

2. The CO2 direct air capture system for increasing CO2 partial pressure according to claim 1, characterized in that: The liquid inlet of the CO2 capture device 3 is also connected to a liquid replenishing pipe for replenishing new absorption liquid from the outside.

3. The CO2 direct air capture system for increasing CO2 partial pressure according to claim 1, characterized in that: The CO2 capture device contains an absorption liquid, which is selected from a single amine absorption liquid, a mixed amine absorption liquid and an ion solution.

4. The CO2 direct air capture system for increasing CO2 partial pressure according to claim 3, characterized in that: The single amine absorption liquid is selected from monoethanolamine MEA, diethanolamine DEA, and methyldiethanolamine MDEA.

5. The CO2 direct air capture system for increasing CO2 partial pressure according to claim 1, characterized in that: All the pipelines are provided with switch valves.

6. The CO2 direct air capture system for increasing CO2 partial pressure according to claim 1, characterized in that: Water pumps are installed on the pipes used for circulating liquid to adjust the flow rate and flow velocity.

7. The CO2 direct air capture system for increasing CO2 partial pressure according to claim 1, characterized in that: The material of the cathode is selected from graphite, carbon cloth, carbon paper, and carbon-supported platinum material, and the material of the anode is selected from carbon paper, carbon cloth, graphite rod, graphite fiber brush, activated carbon, and carbon nanotube.

8. The CO2 direct air capture system for increasing CO2 partial pressure according to claim 1, characterized in that: An oxygen sensor is arranged in the cathode chamber to monitor the oxygen concentration in the cathode chamber.

9. A method for direct air capture of CO2 to increase the partial pressure of CO2, characterized in that: The system capture according to any one of claims 1 to 8 comprises the following steps: Step 1: Increase CO2 partial pressure Water containing organic matter is introduced into the anode chamber of the microbial fuel cell device, CO2 absorbing liquid is injected into the CO2 capture device, and the first air pump is turned on to pump air into the cathode chamber of the microbial fuel cell device. Oxygen in the air participates in the reaction in the cathode chamber and is consumed. The CO2 partial pressure in the deoxygenated air is increased and is pumped into the CO2 capture device through the second air pump; Step 2: CO2 capture and adsorption The air with increased CO2 partial pressure enters the CO2 capture device and is adsorbed by the CO2 absorption liquid therein, and the CO2 absorption liquid becomes rich liquid; Step 3: CO2 thermal desorption The rich liquid enters the jacket outside the reactor box of the microbial fuel cell device from the CO2 capture device. The heat generated by the reaction inside the reactor box heats the rich liquid in the jacket. The heated rich liquid enters the electric heating desorber and is further heated to thermally desorb CO2. CO2 gas is desorbed from the rich liquid. Step 4: CO2 storage The CO2 gas produced by the reaction in the anode chamber of the microbial fuel cell device enters the CO2 compressor through a pipeline, and the CO2 gas desorbed from the rich liquid in the electric heating desorber also enters the CO2 compressor through a pipeline. The CO2 compressor compresses the CO2 gas and transports it to the CO2 storage device for storage.

10. The method according to claim 9, characterized in that: The water containing organic matter in step 1 is organic wastewater containing sugars, fats and proteins.

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