CN115253627A - System and method for capturing and utilizing carbon dioxide in air - Google Patents

Abstract

The invention discloses a system and method for capturing and utilizing carbon dioxide in the air. The system includes an adsorption tower for inputting air and an alkaline solution to obtain a weak alkaline solution; an electrolytic cell stack, the electrolytic cell stack It is composed of a plurality of electrolytic cell units in cycles; the cathode flow channel is used to pass the weak alkaline solution obtained by the adsorption tower as the catholyte, and the anode flow channel is used to pass the alkaline solution as the anode solution; the cathode load There is a cathode catalyst, which is used to decompose the dissolved carbon dioxide in the catholyte to generate hydrogen and methanol; the anode is loaded with an anode catalyst, which is used to decompose water and generate oxygen; the pressure swing adsorption tower is used to separate and purify the output hydrogen; the distillation separation tower is used for In separation and purification output methanol. The system of the present invention can reduce the entropy increase of the process and reduce the cost of digestion, calcination, carbon dioxide compression and transportation of traditional air carbon dioxide capture.

Description

A system and method for capturing and utilizing carbon dioxide in the air

technical field

The invention belongs to the technical field of carbon dioxide capture and utilization, in particular to a system and method for capturing and utilizing carbon dioxide in the air.

Background technique

The core of biological metabolism is to store and release energy through the conversion of different oxidation states of carbon to synthesize functional molecules; the oxidation of carbon is also the center of human "industrial metabolism", such as the combustion and release of fuel and the conversion of various carbon-containing functional molecules with energy storage. In biological metabolism, the reduction of carbon dioxide in photosynthesis balances the oxidation of carbon in respiration; in industrial metabolism, compared with the rapidly developing carbon oxidation technology, the vacancy of carbon reduction technology leads to an unbalanced industrial carbon cycle. The imbalance of the industrial carbon cycle has caused a major disturbance in the earth's carbon cycle, triggering a series of climate and environmental issues; in accordance with the "Paris Climate Agreement", in order to limit global warming to a relatively safe Atmospheric carbon dioxide should be kept below 350ppm. However, as of the beginning of 2020, the concentration of atmospheric carbon dioxide has exceeded 415ppm, which makes the task of carbon emission control arduous. Realize the capture and conversion of carbon dioxide.

At present, the existing air carbon dioxide capture technologies are mainly divided into three types: alkaline solution capture, amine solution capture and solid adsorption capture; Costs remain high. In addition, traditional carbon dioxide storage technologies, such as geological storage, have problems such as economics, long-term safety and reliability, and cannot be applied on a large scale.

As an emerging technology, the use of carbon dioxide can reduce carbon dioxide emissions while achieving energy production and efficiency increases, chemical conversion and synthesis, etc., which is a way to reduce emissions with additional economic benefits. Among them, using carbon dioxide as a carbon source and utilizing the surplus electric energy of new energy sources to produce organic compounds and fuels is a sustainable method to promote the consumption of new energy sources, recycle carbon dioxide, and achieve industrial carbon neutrality. However, the research on carbon dioxide electrocatalysis requires the supply of high-purity carbon dioxide gas, and the high cost of carbon dioxide purification limits the industrial application of the technology.

Contents of the invention

The purpose of the present invention is to provide a system and method for capturing and utilizing carbon dioxide in the air, so as to solve one or more technical problems mentioned above. The system of the present invention can reduce the entropy increase of the process, and reduce the cost of digestion, calcination, carbon dioxide compression and transportation of traditional air carbon dioxide capture.

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

A system for capturing and utilizing carbon dioxide in the air provided by the present invention includes:

反应获得弱碱性溶液；Adsorption tower, used for inputting air and alkaline solution, generating

Reaction obtains weak alkaline solution;

An electrolytic cell stack, the electrolytic cell stack is composed of a plurality of electrolytic cell units periodically; each electrolytic cell unit includes: a combined current collecting plate, the material of the combined current collecting plate is a conductive material for providing potential; The combined current collecting plate forms a plurality of flow channels, and a cathode and an anode are arranged in the flow channel; a bipolar membrane is arranged between the cathode and the anode, and the bipolar membrane is pressed by an anion selective membrane and a cation selective membrane. Combined (for illustration, there may be a catalyst such as Pt between the membranes to promote the dissociation of water), the cation selective membrane is opposite to the cathode, the anion selective membrane is opposite to the anode, and the cathode side is provided The flow channel is the cathode flow channel, and the flow channel on the side with the anode is the anode flow channel; The alkaline solution is used as the anolyte; the cathode is loaded with a cathode catalyst for decomposing dissolved carbon dioxide in the catholyte to generate hydrogen and methanol; the anode is loaded with an anode catalyst for decomposing water to generate oxygen;

The pressure swing adsorption tower is used to input the mixed gas output from the cathode channel, separate and purify the output hydrogen;

The distillation separation tower is used to input the mixed liquid output from the cathode flow channel, separate and purify the output methanol.

A further improvement of the present invention is to also include:

A gas-liquid separation chamber, the inlet of the gas-liquid separation chamber communicates with the outlet of the anode channel, the gas outlet of the gas-liquid separation chamber is used to output the oxygen obtained by separation, and the liquid outlet of the gas-liquid separation chamber Used to output the electrolyte obtained by separation;

The electrolytic solution is used as the alkaline solution input into the adsorption tower.

A further improvement of the present invention is to also include:

A gas storage tank for storing the hydrogen output from the pressure swing adsorption tower;

The product liquid storage tank is used for storing the methanol output from the distillation separation tower.

A further improvement of the present invention is that the adsorption tower includes a main body of the adsorption tower;

The main body of the adsorption tower is sequentially provided with a liquid storage area, an air inlet, a packing area, a spray area and an air outlet from bottom to top; wherein, the spray area is used to spray the alkaline solution in the form of tiny droplets; The packing area is used to increase the contact area and contact time between the alkaline solution and air.

A further improvement of the present invention is that the alkaline solution is potassium hydroxide solution.

A further improvement of the present invention lies in that the pH of the weak alkaline solution is 7.3-8.

A further improvement of the present invention lies in that the flow channels surrounded by the combined collector plates are serpentine, staggered or bionic corrugated.

A further improvement of the present invention is that the cathode catalyst supported by the cathode is a copper-based alloy nanoparticle catalyst; the anode catalyst supported by the anode is a platinum or nickel nanoparticle catalyst.

A further improvement of the present invention is that the temperature of the electrolytic cell stack is maintained at 40°C to 70°C.

A method for capturing and utilizing carbon dioxide in the air provided by the present invention, based on the above-mentioned system of the present invention, comprises the following steps:

反应获得弱碱性溶液；The adsorption tower enters air and alkaline solution, and

Reaction obtains weak alkaline solution;

产生的H⁺经由阳离子选择膜输运至阴极液中，在阴极液里发生反应

产生的二氧化碳与阴极催化剂反应活性位点处发生二氧化碳直接电解反应CO_2(aq)+6e^-+6H⁺→CH₃OH+H₂O；阴极发生析氢副反应2H⁺+2e^-→H₂；阳极发生析氧反应4OH^--4e^-→O₂+2H₂O；The cathode channel of the electrolytic cell unit in the electrolytic cell stack is passed into the weakly alkaline solution obtained by the adsorption tower as the catholyte, and the anode flow channel is passed into the alkaline solution as the anolyte; the hydrolysis reaction

The generated H ⁺ is transported to the catholyte through the cation selective membrane, and reacts in the catholyte

The generated carbon dioxide reacts with the active site of the cathode catalyst to directly electrolyze CO _2(aq) +6e ^- +6H ⁺ →CH ₃ OH+H ₂ O; the hydrogen evolution side reaction 2H ⁺ +2e ^- →H ₂ occurs at the cathode; Oxygen evolution reaction 4OH ^- -4e ^- →O ₂ +2H ₂ O occurs at the anode;

The pressure swing adsorption tower inputs the mixed gas output from the cathode flow channel, separates and purifies the output hydrogen;

The mixed liquid output from the cathode flow channel is input into the distillation separation tower, and the methanol is output through separation and purification.

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

The present invention couples the air carbon dioxide capture and utilization system, based on the characteristics of bipolar membrane hydrolysis, uses the intermediate products of traditional air capture technology (explanatory, including bicarbonate, etc.) as the carbon source of the carbon dioxide utilization system instead of the traditional The high-purity gas-phase carbon dioxide of the carbon dioxide utilization system reduces the entropy increase of the process, greatly reduces the cost of digestion, calcination, carbon dioxide compression and transportation of traditional air carbon dioxide capture; replaces the meteorological reactant with liquid-phase reactant, improves the stability of the reaction. In addition, the organic combination of capture and utilization systems not only reduces costs and improves conversion efficiency, but also realizes resource utilization of carbon dioxide and stable storage of clean energy, which has significant social and circular economic benefits and can be widely used in carbon capture and utilization.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art; obviously, the accompanying drawings in the following description are For some embodiments of the present invention, those skilled in the art can also obtain other drawings based on these drawings without creative effort.

Fig. 1 is a schematic structural view of an air carbon dioxide capture and utilization comprehensive system according to an embodiment of the present invention;

2 is a schematic diagram of an adsorption tower of an air carbon dioxide capture and utilization comprehensive system according to an embodiment of the present invention;

3 is a schematic diagram of an electrolytic cell stack of an air carbon dioxide capture and utilization comprehensive system according to an embodiment of the present invention;

Among them, 1-adsorption tower; 2-alkaline liquid storage tank; 3-gas-liquid separation chamber; 4-electrolytic cell stack; 5-pressure swing adsorption tower; 6-gas storage tank; 7-distillation separation tower; 8-product liquid storage tank;

1-1-air inlet; 1-2-filling area; 1-3-spray area; 1-4-air outlet; 1-5-alkali solution pipeline; 1-6-storage area; 1-7 alkali resistance Water pump; 1-8-solution inlet; 1-9-solution outlet;

3-1-Combined collector plate; 3-2-Cathode channel; 3-3-Cathode; 3-4-Bipolar membrane; 3-5-Anode; 3-6-Anode channel; 3-7-Electrolysis Cell stack entrance; 3-8-electrolytic cell stack exit.

Detailed ways

In order to enable those skilled in the art to better understand the solutions of the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only It is an embodiment of a part of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

It should be noted that the terms "first" and "second" in the description and claims of the present invention and the above drawings are used to distinguish similar objects, but not necessarily used to describe a specific sequence or sequence. It is to be understood that the data so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein can be practiced in sequences other than those illustrated or described herein. Furthermore, the terms "comprising" and "having", as well as any variations thereof, are intended to cover a non-exclusive inclusion, for example, a process, method, system, product or device comprising a sequence of steps or elements is not necessarily limited to the expressly listed instead, may include other steps or elements not explicitly listed or inherent to the process, method, product or apparatus.

The present invention is described in further detail below in conjunction with accompanying drawing:

Please refer to Fig. 1, Fig. 1 is a schematic structural diagram of an air carbon dioxide capture and utilization comprehensive system according to an embodiment of the present invention; an air carbon dioxide capture and utilization comprehensive system according to an embodiment of the present invention includes: a capture module and a conversion storage module.

The capture module includes an alkali-resistant liquid storage tank 2 and an adsorption tower 1; wherein, the alkaline liquid storage tank 2 is connected to the solution inlet 1-8 of the adsorption tower to supply the alkaline adsorption solution;

Please refer to Fig. 2. Fig. 2 is a schematic diagram of an adsorption tower of an air carbon dioxide capture and utilization comprehensive system according to an embodiment of the present invention; in an embodiment of the present invention, the adsorption tower part includes:

Air inlet 1-1, which is located at the lower end of the adsorption tower, blows air into the adsorption tower through a blower;

Filling area 1-2, which is located at the lower end of the spray area, increases the contact area and contact time between the alkaline adsorption solution and air;

Spray zone 1-3, located at the upper end of the packing area, sprays the alkaline adsorption solution to the lower end of the tower in the form of tiny droplets, greatly increasing the contact area between the alkaline adsorption solution and the air;

Air outlets 1-4, which are located at the upper end of the adsorption tower, are used to discharge the adsorbed air;

Alkaline solution pipeline 1-5, used to transport alkaline adsorption solution to the spray area;

Liquid storage area 1-6, located at the bottom of the adsorption tower, is used to store the alkaline adsorption solution after adsorption;

Alkali-resistant water pumps 1-7 are connected with the liquid storage area and the alkali solution pipeline, and pump the alkaline adsorption solution;

Solution inlets 1-8 are connected with the liquid storage area to supply alkaline adsorption solution;

The solution outlets 1-9 are connected with the electrolytic cell stack to supply the adsorption solution meeting the requirements.

The above-mentioned conversion and storage module in the embodiment of the present invention includes a gas-liquid separation chamber 3, an electrolytic cell stack 4, a pressure swing adsorption tower 5, a gas storage tank 6, a distillation separation tower 7, and a product liquid storage tank 8; wherein, the electrolytic cell stack is composed of multiple An electrolytic cell unit cycle is combined.

Please refer to Fig. 3, Fig. 3 is a schematic diagram of the electrolytic cell stack of the air carbon dioxide capture and utilization comprehensive system according to an embodiment of the present invention; in the embodiment of the present invention, an electrolytic cell unit includes:

Merge the current collecting plate 3-1, which is a conductive material, with flow channels on both sides to provide potential;

Cathode channel 3-2, the alkaline adsorption solution that has been absorbed from the adsorption tower flows inside, providing reactants for the cathode and taking away the cathode product;

The cathode 3-3, on which the cathode catalyst is loaded, decomposes the dissolved carbon dioxide in the cathode flow channel to generate products such as hydrogen and methanol;

The bipolar membrane 3-4 is composed of an anion selective membrane and a cation selective membrane, wherein the cation selective membrane is opposite to the cathode, and the anion selective membrane is opposite to the anode;

Anode 3-5, on which an anode catalyst is loaded to decompose water and generate oxygen;

The anode channel 3-6 has an alkaline solution supplied by the alkaline liquid storage tank, which provides reactants for the anode and takes away the anode product;

Electrolytic cell stack inlets 3-7, the inlets are divided into catholyte and anolyte inlets, wherein the catholyte inlet is connected to the solution inlet of the adsorption tower, and the anolyte inlet is connected to the alkaline liquid storage tank;

The outlets of the electrolytic cell stack are 3-8, and the outlets are divided into catholyte and anolyte outlets, wherein the catholyte outlet is connected to the distillation separation tower, and the anolyte outlet is connected to the alkaline liquid storage tank.

The gas-liquid separation chamber 3 in the embodiment of the present invention is connected to the outlet of the anolyte, and separates oxygen and electrolyte in the anolyte.

The pressure swing adsorption tower 5 in the embodiment of the present invention is connected to the outlet of the catholyte, and separates gas phase products such as hydrogen generated by the cathode.

The gas storage tank 6 in the embodiment of the present invention is connected with the pressure swing adsorption tower 5, and stores the separated gas phase product,

The distillation and separation tower 7 in the embodiment of the present invention is connected to the catholyte outlet, and distills and separates liquid phase products such as methanol from the electrolysis of carbon dioxide.

The product liquid storage tank 8 in the embodiment of the present invention is connected with the distillation separation tower, and stores the separated liquid phase product.

In the air carbon dioxide capture and utilization comprehensive system provided by the embodiment of the present invention, the alkaline adsorption solution stored in the alkaline liquid storage tank is potassium hydroxide solution, and the concentration of the solution may be 0.1-2M.

In addition, in order to further ensure that the catholyte of the electrolytic cell stack is potassium bicarbonate solution, the pH of the alkaline adsorption solution in the storage area of the adsorption tower supplied to the electrolytic cell stack can be reduced to 7.3-8.

In the embodiment of the present invention, the packing in the packing area of the adsorption tower is alkali-resistant square, hexagonal or alternating packing plates.

In the embodiment of the present invention, the electrolytic cell stack and the current collecting plate are made of corrosion-resistant conductive materials such as graphite and titanium plates, and the upper flow channel can be serpentine, staggered or bionic corrugated.

In the embodiment of the present invention, the cathode of the electrolytic cell stack is a carbon fiber felt loaded with copper-based alloy nanoparticle catalysts such as Cu single atom, Cu-Co double metal single atom, CuPd or CuSe, and the anode is a carbon fiber felt loaded with nanoparticle catalysts such as platinum and nickel. .

In the embodiment of the present invention, in order to promote the reaction, the temperature of the electrolytic cell stack is maintained at 40°C to 70°C.

In the embodiment of the present invention, the electric energy supply of the electrolytic cell stack is clean energy such as photovoltaic, wind power and hydropower.

The air carbon dioxide capture and utilization system provided in the embodiment of the present invention also includes a controller for controlling the operation of the capture module and the conversion storage module, and the controller includes a general processor, a digital signal processor, an application specific integrated circuit ASIC or In the field programmable gate array FPGA, the controller includes memory, and the memory includes one or more read-only memory ROM, random access memory RAM, flash memory or electronically erasable programmable read-only memory EEPROM.

A method for capturing and utilizing an air carbon dioxide capture and utilization system provided in an embodiment of the present invention includes the following steps:

The air is blown into the adsorption tower through the blower, and the carbon dioxide in the air reacts with the alkaline solution sprayed in the adsorption tower and provided by the alkaline liquid storage tank as follows:

其中H⁺经由阳离子选择膜输运至阴极液中，在阴极液里发生反应，

产生的二氧化碳与阴极催化剂反应活性位点处发生二氧化碳直接电解反应：CO_2(aq)+6e^-+6H⁺→CH₃OH+H₂O；The alkaline solution fully reacts with the air to obtain a weakly alkaline solution rich in bicarbonate ions. The weakly alkaline solution and the alkaline solution in the alkaline storage tank are respectively supplied to the electrolytic cell stack as catholyte and anolyte. In the pool stack, the bipolar membrane undergoes a hydrolysis reaction,

Among them, H ⁺ is transported to the catholyte through the cation selective membrane, and reacts in the catholyte,

The carbon dioxide generated and the active site of the cathode catalyst undergo a direct electrolysis reaction of carbon dioxide: CO _2(aq) +6e ^- +6H ⁺ →CH ₃ OH+H ₂ O;

The hydrogen evolution side reaction also occurs at the cathode: 2H ⁺ +2e ^- → H ₂ ; the oxygen evolution reaction occurs at the anode side: 4OH ^- -4e ^- → O ₂ +2H ₂ O;

At the outlet of the electrolytic cell stack, the anolyte outlet is connected to the gas-liquid separation chamber, the oxygen is separated from the electrolyte, the oxygen is stored or discharged, and the electrolyte is replenished to the alkaline liquid storage tank. The mixed gas at the catholyte outlet is connected to the pressure swing adsorption tower to separate and purify hydrogen, and the mixed liquid is connected to the distillation separation tower to separate and purify methanol. The hydrogen and methanol are stored in the gas storage tank and the product liquid storage tank respectively.

The air carbon dioxide capture and utilization comprehensive system provided by the embodiment of the present invention can realize efficient capture and conversion of air carbon dioxide. Compared with the traditional carbon dioxide alkaline solution capture system, the structure is simple, there is no digestion and calcination process, and the cost of digestion and calcination process and the loss of carbon dioxide are avoided. Compared with the carbon dioxide electrolysis system, the cathode of the carbon dioxide electrolysis cell only supplies the solution, and does not need to introduce carbon dioxide gas, which greatly simplifies the carbon dioxide purification process. The purification and reaction of carbon dioxide are respectively placed near the bipolar membrane and the cathode, reducing the cost of carbon dioxide purification and transportation. In addition, the good ion barrier properties of the bipolar membrane avoid the crossover of anode and cathode products, reduce the consumption and pollution of the alkaline solution on the anode side, and realize the recycling of the alkaline solution on the anode side. The organic coupling of the capture system and the utilization system not only realizes the resource utilization of carbon dioxide, but also realizes the stable storage of new energy electric energy, reduces the rate of abandonment of light and wind in new energy power plants, and achieves the purpose of carbon reduction.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: the present invention can still be Any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention shall fall within the protection scope of the claims of the present invention.

Claims (10)

1. A system for capture utilization of carbon dioxide in air, comprising:

an adsorption column (1) for the input of air and alkaline solution, generating

Reacting to obtain a weakly alkaline solution;

the electrolytic cell stack (4), the electrolytic cell stack (4) is formed by periodically combining a plurality of electrolytic cell units; each cell unit comprises: the combined current collecting plate (3-1), the material of the combined current collecting plate (3-1) is a conductive material, and is used for providing electric potential; the combined collector plate (3-1) is enclosed into a plurality of flow channels, and cathodes (3-3) and anodes (3-5) are arranged in the flow channels; a bipolar membrane (3-4) is arranged between the cathode (3-3) and the anode (3-5), the bipolar membrane (3-4) is formed by laminating an anion selective membrane and a cation selective membrane, the cation selective membrane is opposite to the cathode (3-3), the anion selective membrane is opposite to the anode (3-5), a flow channel at one side provided with the cathode (3-3) is a cathode flow channel (3-2), and a flow channel at one side provided with the anode (3-5) is an anode flow channel (3-6); the cathode flow channel (3-2) is used for introducing the weak alkaline solution obtained by the adsorption tower (1) as catholyte, and the anode flow channel (3-6) is used for introducing an alkaline solution as anolyte; the cathode (3-3) is loaded with a cathode catalyst and is used for decomposing carbon dioxide dissolved in catholyte to generate hydrogen and methanol; the anode (3-5) is loaded with an anode catalyst and is used for decomposing water to generate oxygen;

the pressure swing adsorption tower (5) is used for inputting the mixed gas output by the cathode flow channel, separating, purifying and outputting hydrogen;

and the distillation separation tower (7) is used for inputting the mixed liquid output by the cathode flow channel, separating, purifying and outputting the methanol.

2. The system for capture utilization of carbon dioxide in air according to claim 1, further comprising:

the inlet of the gas-liquid separation chamber (3) is communicated with the outlet of the anode runner, the gas outlet of the gas-liquid separation chamber (3) is used for outputting oxygen obtained by separation, and the liquid outlet of the gas-liquid separation chamber (3) is used for outputting electrolyte obtained by separation;

the electrolyte is used as an alkaline solution fed to the adsorption column (1).

3. The system for capture utilization of carbon dioxide in air according to claim 1, further comprising:

the gas storage tank (6) is used for storing the hydrogen output by the pressure swing adsorption tower (5);

and the product liquid storage tank (8) is used for storing the methanol output by the distillation separation tower (7).

4. The system for capture utilization of carbon dioxide in air according to claim 1, characterized in that the adsorption tower (1) comprises an adsorption tower body;

the adsorption tower main body is sequentially provided with a liquid storage area (1-6), an air inlet (1-1), a filler area (1-2), a spraying area (1-3) and an air outlet (1-4) from bottom to top; wherein the spraying area (1-3) is used for spraying the alkaline solution in the form of tiny droplets; the packing region (1-2) is used for increasing the contact area and the contact time of the alkaline solution and air.

5. The system for capture utilization of carbon dioxide in air according to claim 1, wherein the alkaline solution is a potassium hydroxide solution.

6. The system for capturing and utilizing carbon dioxide in the air as claimed in claim 1, wherein the pH of the weak alkaline solution is 7.3-8.

7. The system for capturing and utilizing carbon dioxide in air as claimed in claim 1, wherein the flow channel enclosed by the combining and collecting plate (3-1) is serpentine, staggered or bionic corrugated.

8. The system for capture utilization of carbon dioxide in air according to claim 1, characterized in that the cathode catalyst supported by the cathode (3-3) is a copper-based alloy nanoparticle catalyst; the anode catalyst loaded on the anode (3-5) is a platinum and nickel nanoparticle catalyst.

9. The system for capture and utilization of carbon dioxide in air according to claim 1, characterized in that the temperature of the electrolytic cell stack (4) is maintained at 40-70 ℃.

10. A method for capture utilization of carbon dioxide in air, based on the system of claim 1, comprising the steps of:

the adsorption tower (1) inputs air and alkaline solution to generate

Reacting to obtain a weakly alkaline solution;

a cathode flow channel of an electrolytic cell unit in the electrolytic cell stack (4) is filled with the alkalescent solution obtained by the adsorption tower (1) to be used as catholyte, and an anode flow channel is filled with an alkaline solution to be used as anolyte; hydrolysis reaction

Generation of H ⁺ Transported to the cathode liquid through the cation selective membrane, and reacted in the cathode liquid

The generated carbon dioxide and the carbon dioxide at the reaction active site of the cathode catalyst are subjected to direct electrolysis reaction CO _2(aq) +6e ^- +6H ⁺ →CH ₃ OH+H ₂ O; side reaction 2H of hydrogen evolution at cathode ⁺ +2e ^- →H ₂ (ii) a The anode generates oxygen evolution reaction 4OH ^- -4e ^- →O ₂ +2H ₂ O；

The pressure swing adsorption tower (5) inputs the mixed gas output by the cathode flow channel, separates, purifies and outputs hydrogen;

the distillation separation tower (7) inputs the mixed liquid output by the cathode flow passage, and the methanol is separated, purified and output.

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