Natural mineral wet mineralization CO2 capture stock solution direct electrolysis technology

Abstract

A direct electrolysis technology for a natural mineral wet mineralization CO2 capture stock solution belongs to the field of carbon capture and resource utilization, and is characterized in that CO2 is captured through natural mineral wet mineralization to generate a bicarbonate solution, an electrolytic bath is constructed by using a bismuth-based catalyst and a cation exchange membrane to directly electrolyze to generate formate, and the formate is directly electrolyzed to generate the CO2 capture stock solution. Formate and regenerated trapping liquid are separated through a bipolar membrane electrodialysis technology, slag can be converted into a silicon-based building material, and integration of emission reduction, value addition and circulation is achieved. Compared with a traditional amine trapping technology, the method has the advantages that the energy consumption is reduced by 40%-50%, the trapping liquid raw material cost is reduced by 60%-70%, the problems of solvent volatilization and equipment corrosion are avoided, and the method is suitable for distributed carbon trapping and resource conversion in high-emission industries such as steel and chemical engineering.

Description

Technical Field

[0001] The present invention relates to the field of carbon capture and utilization (CCUS) technology, specifically a natural mineral wet mineralization CO2 capture stock solution direct electrolysis technology, which is suitable for industrial carbon emission control and high value-added chemical production. Background Art

[0002] Traditional CO2 capture technology (such as the amine method) relies on high-temperature desorption and regeneration, with energy consumption as high as 2-4GJ / tCO2, and there are problems such as solvent volatilization and equipment corrosion. Although the direct electrolysis capture liquid (DECL) technology eliminates the desorption step, it still faces challenges such as high capture liquid cost (industrial-grade KOH is 6,000-8,000 yuan per ton) and slow reduction kinetics. For example, patent CN119098036A proposes an intelligent control system for wet mineralization of alkali-based solid waste, but does not solve the problems of high capture liquid raw material cost and low electrolysis efficiency; patent CN115400550B uses electrochemical decoupling capture technology. Although the energy consumption is reduced to 1.12GJ / t-CO2, it does not involve the carbon resource utilization path of natural minerals and electrolysis. In addition, existing mineralization technologies mostly rely on high-temperature calcination (such as 900°C for carbide slag mineralization) or complex pretreatment, resulting in high system energy consumption and cost. Therefore, there is an urgent need to develop an integrated capture-conversion technology that combines low energy consumption, high selectivity and resource recycling. Summary of the Invention

[0003] The present invention proposes a natural mineral wet mineralization CO2 capture solution direct electrolysis technology, which is achieved through the following steps:

[0004] Step 1: CO2 capture module: using K-rich + / Na + Natural minerals (such as potassium feldspar and sodium montmorillonite) react with CO2 in the liquid phase to form bicarbonate solution, and the slag is separated and used in the production of silicon-based building materials;

[0005] Step 2: Electrolysis module: Use bismuth-based catalyst and cation exchange membrane (CEM) to build an electrolytic cell, and convert HCO3 into - Highly efficient reduction to formate (selectivity up to 85%), anodic water oxidation provides H + and maintain charge balance;

[0006] Step 3, electrodialysis module: Separate formate and regenerated capture liquid through bipolar membrane electrodialysis, realizing the recycling of capture liquid and resource utilization of products.

[0007] Preferably, the natural minerals are pretreated by crushing and thermal activation, and the thermal activation temperature is 200-300°C.

[0008] Preferably, the cathode pH value of the electrolysis module is 8.5-9.0, the electrolysis voltage is 2.0-2.5V, and the formate Faraday efficiency is 70%-100%.

[0009] Preferably, the slag is used to prepare silicate cement or other silicon-based building materials.

[0010] Preferably, the cation exchange membrane (CEM) is a perfluorosulfonic acid membrane or a sulfonated polyetheretherketone membrane.

[0011] In combination with the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solutions to be protected by the present invention are as follows:

[0012] 1. The traditional amine capture method has high energy consumption and high raw material costs (such as KOH 6000-8000 yuan per ton). The present invention replaces chemical solvents with natural minerals, significantly reducing the cost of capture liquid raw materials. At the same time, the electrolysis voltage is optimized to 2.0-2.5V. Combined with the high selectivity of bismuth-based catalysts, the total energy consumption of the system is reduced to 1.5GJ / t-CO2, a 40% reduction in energy consumption.

[0013] 2. Traditional CO2 resource recovery pathways are limited and fail to achieve comprehensive utilization of slag and products. This invention can achieve resource recovery of slag and produce high-value liquid products, with a slag recovery rate of 95% (for building materials), formate purity >90%, and a capture liquid regeneration rate >85%.

[0014] 3. The present invention proposes a natural mineral wet mineralization CO2 capture solution direct electrolysis technology for the capture, conversion and utilization of carbon dioxide in air or flue gas exhaust. Through the integrated capture-conversion technology, low energy consumption, high selectivity and resource recycling of carbon dioxide can be achieved, which has broad industrial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of a natural mineral wet mineralization CO2 capture solution direct electrolysis technology provided by an embodiment of the present invention.

[0016] In the figure: 1. CO2 capture module; 1a. Capture tower gas inlet; 1b. Capture filler area; 1c. Capture tower gas outlet; 2. Electrolysis module; 2a. Electrolysis reactant inlet (capture liquid outlet); 2b. Electrolysis cathode module; 2c. Electrolysis ion exchange membrane; 2d. Electrolysis gas outlet; 3. Electrodialysis module; 3a. Electrodialysis reactant inlet (electrolysis liquid product outlet); 3b. Bipolar membrane; 3c. Electrodialysis product outlet. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0018] In order to enable those skilled in the art to fully understand how to implement the present invention, this section provides an explanatory embodiment that expands on the technical solutions of the claims.

[0019] like Figure 1 As shown, the present invention provides a natural mineral wet mineralization CO2 capture solution direct electrolysis technology, which is achieved by the following steps:

[0020] Step 1, CO2 capture module 1: including capture tower gas inlet 1a, capture packing area 1b, capture tower gas outlet 1c; specifically, CO2 gas enters from the capture tower gas inlet 1a, reacts in the capture packing area 1b, and unreacted gas is discharged from the capture tower gas outlet 1c; using K-rich + / Na + Natural minerals (such as potassium feldspar and sodium montmorillonite) react with CO2 in the liquid phase to form bicarbonate solution, and the slag is separated and used in the production of silicon-based building materials;

[0021] Step 2, electrolysis module 2: including electrolysis reactant inlet (collection liquid outlet) 2a, electrolysis cathode module 2b, electrolysis ion exchange membrane 2c, electrolysis gas outlet 2d; specifically, the electrolysis reactant inlet (collection liquid outlet) 2a serves as the electrolysis reactant inlet, the collection liquid enters the electrolysis cathode module 2b for reaction, and contains an electrolysis ion exchange membrane 2c in the middle. The gas product is discharged from the electrolysis gas outlet 2d, and the unreacted collection liquid is refluxed. The electrolysis cell is constructed using a bismuth-based catalyst and a cation exchange membrane (CEM), and HCO3 is converted to - Highly efficient reduction to formate (selectivity up to 85%), anodic water oxidation provides H + and maintain charge balance;

[0022] Step 3, electrodialysis module 3: provided with an electrodialysis reactant inlet (electrolyte liquid product outlet) 3a, a bipolar membrane 3b, and an electrodialysis product outlet 3c; specifically, the electrodialysis reactant inlet (electrolyte liquid product outlet) 3a serves as the electrodialysis reactant inlet, the electrolyze liquid product reacts through the bipolar membrane 3b electrolytic cell, and the product is discharged from the electrodialysis product outlet 3c. The formate and the regenerated capture liquid are electrodialyzed and separated by the bipolar membrane 3b, thereby realizing the recycling of the capture liquid and the resource utilization of the product.

[0023] Furthermore, the natural minerals need to be pre-treated by crushing and thermal activation, and the thermal activation temperature is 200-300°C, with the optimal temperature being 220°C.

[0024] Furthermore, the cathode pH value of the electrolysis module 2 is 8.5-9.0, the electrolysis voltage is 2.0-2.5V, and the formate Faraday efficiency is 70%-100%. The optimal cathode pH value, the optimal electrolysis voltage, and the optimal formate Faraday efficiency are 8.8, 2.0V, and 90%.

[0025] Furthermore, the slag is used to prepare silicate cement or other silicon-based building materials.

[0026] Furthermore, the cation exchange membrane (CEM) is a perfluorosulfonic acid membrane or a sulfonated polyetheretherketone membrane.

[0027] In order to make the disclosure of the present invention more complete, it is described below with reference to more specific embodiments.

[0028] Example 1:

[0029] Mineralization capture: crush potassium feldspar to 200 mesh, heat activated at 300℃ for 2 hours, react with CO2 at 25℃ to generate KHCO3 solution, and use it in silicate cement production after slag separation; electrolytic conversion: the electrolytic cell uses Bi2O3 catalyst (loading capacity 10mg / cm 2 ) and Nafion117 cation exchange membrane, the cathode pH was adjusted to 8.8, the electrolysis voltage was 2.2V, and the formate yield was 82%; electrodialysis separation: the mixed solution after electrolysis was electrodialyzed by bipolar membrane 3b (current density 50mA / cm 2 ), the purity of formate reached 92%, and the regeneration rate of the captured liquid was 90%.

[0030] Example 2:

[0031] Mineralization capture: Sodium montmorillonite is crushed to 200 mesh, thermally activated at 250℃ for 2 hours, and reacted with CO2 at 25℃ to generate NaHCO3 solution. The slag is separated and used for silicate cement production; electrolytic conversion: The electrolytic cell uses Bi2O3 catalyst (loading capacity 10mg / cm 2 ) and Nafion 117 cation exchange membrane, the cathode pH was adjusted to 8.5, the electrolysis voltage was 2V, and the formate yield was 90%; electrodialysis separation: the mixed solution after electrolysis was electrodialyzed by bipolar membrane 3b (current density 50mA / cm 2 ), the purity of formate reached 95%, and the regeneration rate of the captured liquid was 90%.

[0032] Example 3:

[0033] Mineralization capture: Sodium montmorillonite is crushed to 200 mesh, thermally activated at 220℃ for 2 hours, and reacted with CO2 at 25℃ to generate NaHCO3 solution. The slag is separated and used for silicate cement production; electrolytic conversion: The electrolytic cell uses Bi2O3 catalyst (loading capacity 10mg / cm 2) and Nafion 117 cation exchange membrane, the cathode pH was adjusted to 9.0, the electrolysis voltage was 2.7 V, and the formate yield was 95%; electrodialysis separation: the mixed solution after electrolysis was electrodialyzed by bipolar membrane 3b (current density 50 mA / cm 2 ), the purity of formate reached 95%, and the regeneration rate of the captured liquid was 90%.

Claims

1. A natural mineral wet mineralization CO2 capture solution direct electrolysis technology, characterized by: This is achieved through the following steps: CO2 capture module, capture raw liquid direct electrolysis module and electrodialysis module, wherein: a.CO2 capture module: using K-rich + / Na + Natural minerals, including at least one of potassium feldspar, sodium zeolite, and sodium montmorillonite, react with CO2 in a liquid phase to generate a bicarbonate solution, and separate the slag by filtration; b. Direct electrolysis module for captured raw solution: This module uses a flow electrolytic cell with a bismuth-based catalyst as the cathode and a cation exchange membrane (CEM) as the core to directly electrolyze the bicarbonate solution into formate; c. Electrodialysis module: Separates formate from regenerated capture liquid through bipolar membrane electrodialysis technology to achieve resource recycling.

2. The direct electrolysis technology for CO2 capture from wet mineralization of natural minerals according to claim 1, characterized in that: The natural minerals need to be crushed and thermally activated beforehand, and the thermal activation temperature is 200-300°C.

3. The direct electrolysis technology for CO2 capture from wet mineralization of natural minerals according to claim 1, characterized in that: The cathode pH value of the captured stock solution direct electrolysis module is 8.5-9.0, the electrolysis voltage is 2.0-2.5V, and the formate Faraday efficiency is 70%-100%.

4. The direct electrolysis technology for CO2 capture from wet mineralization of natural minerals according to claim 1, characterized in that: The slag is used to prepare silicate cement or other silicon-based building materials.

5. The direct electrolysis technology for CO2 capture from wet mineralization of natural minerals according to claim 1, characterized in that: The cation exchange membrane (CEM) is a perfluorosulfonic acid membrane or a sulfonated polyetheretherketone membrane.

6. A system applying the technology described in any one of claims 1 to 5, comprising a CO2 capture device, an electrolyzer, and an electrodialysis device, for distributed carbon capture and resource conversion in high-emission industries such as steel and chemical industries, which can significantly reduce energy consumption and costs.

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