CN-122006447-A - Carbon dioxide capturing system with pH control function

Abstract

The present invention provides a carbon dioxide capture system with pH control that allows for electrolyte recirculation.

Inventors

• Biao Shiyuan
• ZHANG ZHIXUN
• LI YUNZHU

Assignees

• 现代自动车株式会社
• 起亚株式会社

Dates

Publication Date

20260512

Application Date

20250714

Priority Date

20241111

Claims (20)

1. 1. A carbon dioxide capture system, comprising: an electrolyte storage unit configured to store, hold, or hold a first electrolyte containing an alkaline carbonate aqueous solution; A suction unit in fluid communication with the electrolyte storage unit and a gas source, the suction unit configured to (i) receive the first electrolyte of the electrolyte storage unit, (ii) receive a gas mixture from the gas source comprising carbon dioxide, and (iii) prepare a concentrate by dissolving carbon dioxide in the gas mixture into the first electrolyte; A degassing unit in fluid communication with the suction unit and a discharge device, the degassing unit configured to (i) degas carbon dioxide from the concentrate supplied by the suction unit to provide a degassed concentrate, and (ii) discharge carbon dioxide; a dispensing unit in fluid communication with the degassing unit and with at least one dispensing line, the dispensing unit configured to (i) receive the degassed concentrate from the degassing unit and dispense the degassed concentrate through the at least one dispensing line; A first reaction unit in fluid communication with the distribution unit, the first reaction unit configured to react at least a portion of the degassed concentrate from the distribution unit with hydroxide under conditions to produce carbonate and an aqueous alkaline solution, and A second reaction unit in fluid communication with (a) an electrolyte storage unit, (b) a dispensing unit, and (c) a first reaction unit, and configured to (i) react a remaining portion of the degassed concentrate from the dispensing unit with a quantity of an aqueous alkaline solution from the first reaction unit to produce a second electrolyte, and (ii) supply the second electrolyte to the electrolyte storage unit.
2. 2. The system of claim 1, wherein the aqueous basic carbonate solution comprises one or more of an aqueous sodium carbonate (Na 2 CO 3 ) solution, an aqueous potassium carbonate (K 2 CO 3 ) solution, and combinations thereof.
3. 3. The system of claim 1, wherein the basic carbonate aqueous solution has a concentration of 0.0001M to 0.5M.
4. 4. The system of claim 1, wherein the pH of the first electrolyte is 9 to 12.5.
5. 5. The system according to claim 1, wherein the suction unit includes a suction separation membrane dividing an inner space of the suction unit into an electrolyte flow space and a gas mixture flow space, and Wherein the suction separation membrane has permeability to carbon dioxide contained in the gas mixture flowing in the gas mixture flow space and allows carbon dioxide to be dissolved in the first electrolyte in the electrolyte flow space.
6. 6. The system of claim 1, wherein the gas mixture comprises one or more selected from the group consisting of steelmaking byproduct gas, off-gas, and combinations thereof.
7. 7. The system of claim 5, wherein the pressure of the gas mixture flow space is 0.1 bar to 10 bar.
8. 8. The system of claim 5, wherein the pressure of the gas mixture flow space is lower than the pressure of the electrolyte flow space, Wherein a pressure difference between the gas mixture flow space and the electrolyte flow space is in a range of 3 bar or less.
9. 9. The system of claim 1, wherein a ratio of a flow rate of the gas mixture to a flow rate of the first electrolyte supplied to the suction unit is in a range of 0.1 to 15.
10. 10. The system of claim 1, wherein the pH of the concentrate is from 6 to 9.
11. 11. The system of claim 1, wherein the degassing unit comprises a degassing separation membrane that divides an interior space of the degassing unit into a concentrate flow space and a carbon dioxide flow space, and Wherein the degassing separation membrane has permeability to carbon dioxide contained in the concentrated liquid flowing in the concentrated liquid flow space and allows carbon dioxide to be discharged into the carbon dioxide flow space through the degassing separation membrane.
12. 12. The system of claim 1, wherein the degassed concentrate comprises one or more of an aqueous sodium bicarbonate (NaHCO 3 ), an aqueous potassium bicarbonate (KHCO 3 ), and combinations thereof.
13. 13. The system of claim 1, wherein the degassed concentrate has a pH of 7 to 9.
14. 14. The system of claim 1, wherein the hydroxide comprises a hydroxide of one or more metal ions of calcium (Ca), magnesium (Mg), strontium (Sr), copper (Cu), lithium (Li), barium (Ba), iron (Fe), and combinations thereof.
15. 15. The system of claim 1, wherein the molar ratio of partially degassed concentrate and hydroxide reacted with each other in the first reaction unit is in the range of 1:0.5 to 1:2.
16. 16. The system of claim 1, wherein the carbonate comprises a carbonate of one or more metal ions of calcium (Ca), magnesium (Mg), strontium (Sr), copper (Cu), lithium (Li), barium (Ba), iron (Fe), and combinations thereof, and The first reaction unit further includes a filtration unit configured to separate and recover carbonate.
17. 17. The system of claim 1, wherein the aqueous alkaline solution comprises one or more of an aqueous sodium hydroxide (NaOH), an aqueous potassium hydroxide (KOH), and a combination thereof.
18. 18. The system of claim 1, wherein the aqueous alkaline solution has a pH of 12 to 14.
19. 19. The system of claim 1, wherein the molar ratio of the remaining portion of the degassed concentrate to the alkaline aqueous solution reacted with each other in the second reaction unit is in the range of 1:0.5 to 1:1.2.
20. 20. The system of claim 1, wherein the pH of the second electrolyte discharged from the second reaction unit is 9 to 12.5.

Description

Carbon dioxide capturing system with pH control function Technical Field The present invention relates to a carbon dioxide capture system (carbon dioxide capture system) with pH control that enables electrolyte recirculation. Background Recently, studies on electrochemical water electrolysis have been actively conducted to accommodate the development of renewable energy sources to cope with climate change. In addition, carbon dioxide (CO 2) capture, storage, and conversion technologies that reduce greenhouse gases have also become important. Representative carbon dioxide capture technologies include amine compound-based methods, methods using solid absorbents, and methods using membrane contactors. The carbon dioxide capturing method based on an amine compound requires a large amount of energy to regenerate the amine compound and affects the durability of the apparatus due to its high corrosiveness. The method of capturing carbon dioxide using a solid absorbent requires periodic replacement of the absorbent due to deterioration of the absorbent performance, and the absorption rate of carbon dioxide is slow. The method of capturing carbon dioxide using the membrane contactor uses a difference in solubility according to the type of gas. Specifically, the method contacts a gas mixture containing carbon dioxide with an aqueous solution to dissolve and separate carbon dioxide contained in the gas mixture into the aqueous solution. The method of capturing carbon dioxide using a membrane contactor has advantages of high collection efficiency because the reaction between the aqueous solution and carbon dioxide is fast and provides relatively low cost and low energy requirements. Typically, when water is applied to the aqueous solution, the carbon dioxide removal efficiency is shown to be about 85%. Similarly, when propylene carbonate (propylene carbonate) is added to water, a typical carbon dioxide removal efficiency is shown to be about 91%. However, regardless of the state of the art, new techniques that provide higher removal rates are needed in order to more closely approximate or achieve carbon neutrality. Disclosure of Invention In one aspect, the present invention provides a system with very high carbon dioxide capture efficiency. In another aspect, the present invention provides a system capable of continuously capturing carbon dioxide. In another aspect, the present invention provides a system capable of selectively collecting carbon dioxide contained in a gas mixture. In another aspect, the present invention provides a system that is easily scalable. The aspects of the present invention are not limited to the above aspects. Other aspects and embodiments of the invention will become apparent from the description that follows. According to one embodiment of the present invention, a carbon dioxide capturing system may include an electrolyte storage unit (electrolyte storage unit) for storing a first electrolyte containing an alkaline carbonate aqueous solution (aqueous alkaline carbonate solution), an inhalation unit (intake unit) for preparing a concentrated solution by dissolving carbon dioxide contained in a gas mixture into the first electrolyte supplied from the electrolyte storage unit, a degassing unit for degassing (degassing) carbon dioxide from the concentrated solution supplied from the inhalation unit and discharging the carbon dioxide, a dispensing unit for receiving a portion of the effluent (DISCHARGE LIQUID) discharged from the degassing unit and dispensing the effluent, a first reaction unit for preparing carbonate and an alkaline aqueous solution by receiving a portion of the effluent from the dispensing unit and reacting the portion of the effluent with hydroxide, and a second reaction unit for preparing the second electrolyte and supplying the second electrolyte into the electrolyte storage unit, the preparation being completed by receiving a remaining portion of the effluent from the dispensing unit and the alkaline aqueous solution from the first reaction unit and reacting the remaining portion of the effluent with the alkaline aqueous solution. The aqueous alkaline carbonate solution may include one or more selected from the group consisting of aqueous sodium carbonate (Na 2CO3), aqueous potassium carbonate (K 2CO3), and combinations thereof. The concentration of the aqueous alkali carbonate solution may be 0.0001M to 0.5M. The pH of the first electrolyte may be 9 to 12.5. The suction unit may include a suction separation membrane (intake separation membrane) installed therein to divide a space of the suction unit into an electrolyte flow space and a gas mixture flow space. Carbon dioxide contained in the gas mixture and flowing in the gas mixture flow space can be sucked into the separation membrane through (pass through) and dissolved in the first electrolyte flowing in the electrolyte flow space. The gas mixture may include one or more selected from the group consisting of steelmaki