KR-20260067742-A - DESALINATION AND ELECTROLYSIS DEVICE USING salinity gradient power generation

KR20260067742AKR 20260067742 AKR20260067742 AKR 20260067742AKR-20260067742-A

Abstract

The present invention provides a seawater desalination and water electrolysis device using salinity gradient power generation technology, comprising: a reverse electrodialysis stack; and osmotic membranes disposed on both sides of the reverse electrodialysis stack, wherein the reverse electrodialysis stack comprises an anode electrode; a cathode electrode; a first cell disposed between the anode electrode and the cathode electrode and comprising a cation exchange membrane, an anion exchange membrane, and a bipolar membrane; and a second cell disposed between the first cell and the cathode electrode and comprising a cation exchange membrane and an anion exchange membrane.

Inventors

정남조
정윤철
한지형
김선이
좌은진
김한기
황교식

Assignees

한국에너지기술연구원

Dates

Publication Date: 20260513
Application Date: 20241106

Claims (12)

A reverse electrodialysis stack; and osmotic membranes disposed on both sides of the reverse electrodialysis stack, comprising The above reverse electrodialysis stack comprises an anode electrode; a cathode electrode; a first cell disposed between the anode electrode and the cathode electrode and comprising a cation exchange membrane, an anion exchange membrane, and a bipolar membrane; and a second cell disposed between the first cell and the cathode electrode and comprising a cation exchange membrane and an anion exchange membrane, a seawater desalination and water electrolysis device using salinity gradient power generation technology.
In Article 1, A freshwater generating unit that supplies water between the cation exchange membrane (CEM) and the anion exchange membrane (AEM) of the first cell and the second cell to generate and discharge additional freshwater and recirculate raw water; An acid solution circulation unit that circulates an acid solution between the above osmotic membrane and the above first cell, and between the bipolar membrane of the first cell and the cation exchange membrane of the second cell; A base solution circulation unit that circulates a base solution between the osmotic membrane and the second cell, and between the anion exchange membrane and the bipolar membrane of the first cell; An end plate disposed on the outer side of the above osmotic membrane; and A seawater desalination and water electrolysis device using salinity gradient power generation technology, further comprising a seawater supply unit that supplies seawater between the above-mentioned osmotic membrane and the above-mentioned end plate.
In Article 2 A seawater desalination and water electrolysis device using salinity gradient power generation technology, wherein the acid solution comprises at least one from the group consisting of aqueous solutions of H₂SO₄ , HNO₃ , H₃PO₄ , HVO₃ , H₂CO₃ , and HBrO when the production of O₂ (g) is dominant, and at least one from the group consisting of aqueous solutions of HCl, LiCl, and NH₄Cl when the production of Cl₂ (g) is dominant.
In Article 2, A seawater desalination and water electrolysis device using salinity gradient power generation technology, wherein the above-mentioned base solution comprises at least one from the group consisting of aqueous solutions of NaOH, KOH, and NH₄OH .
In Article 2, A seawater desalination and water electrolysis device using salinity gradient power generation technology, further comprising a carbon dioxide mineralization unit that generates carbonates in high-concentration concentrated water discharged between the osmotic membrane and the end plate by the seawater supply unit.
A reverse electrodialysis stack; and osmotic membranes disposed on both sides of the reverse electrodialysis stack, comprising The above reverse electrodialysis stack comprises an anode electrode; a cathode electrode; a first cell disposed between the anode electrode and the cathode electrode and comprising a cation exchange membrane (CEM), an anion exchange membrane (AEM), and a bipolar membrane (BPM); a second cell disposed between the first cell and the cathode electrode and comprising a cation exchange membrane (CEM) and an anion exchange membrane (AEM); a third cell disposed between the anode electrode and the first cell and comprising a cation exchange membrane (CEM), an anion exchange membrane (AEM), and a bipolar membrane (BPM) in the same manner as the first cell; and a fourth cell disposed between the first cell and the second cell and comprising a cation exchange membrane (CEM), an anion exchange membrane (AEM), and a bipolar membrane (BPM) in the same manner as the first cell, a seawater desalination and water electrolysis device using salinity gradient generation technology.
In Article 6, A fresh water, acid solution, and base solution generating unit that supplies water between the cation exchange membrane (CEM) and the anion exchange membrane (AEM) of the first cell, the second cell, the third cell, and the fourth cell, and generates and discharges fresh water, an acid solution, and a base solution by means of a pH neutralization reaction of H + and OH- that have moved to the water supplied through the cation exchange membrane and the anion exchange membrane, respectively; An acid solution circulation unit that circulates an acid solution between the osmotic membrane and the third cell, between the bipolar membrane (BPM) of the third cell and the cation exchange membrane (CEM) of the first cell, and between the bipolar membrane (BPM) of the first cell and the cation exchange membrane (CEM) of the fourth cell; A base solution circulation unit that circulates a base solution between the above osmotic membrane and the above second cell, between the anion exchange membrane (AEM) and the bipolar membrane (BPM) of the above first cell (140), and between the anion exchange membrane (AEM) and the bipolar membrane (BPM) of the above fourth cell; An end plate disposed on the outer side of the above osmotic membrane; A seawater circulation unit that supplies seawater between the osmotic membrane and the end plate, and supplies concentrated water between the anion exchange membrane and the bipolar membrane (BPM) of the third cell, and between the cation exchange membrane and the bipolar membrane (BPM) of the second cell; and A seawater desalination and water electrolysis device utilizing salinity gradient power generation technology, further comprising an oxidation electrode and a reduction electrode in contact with the above-mentioned osmotic membrane.
In Article 7, A seawater desalination and water electrolysis device using salinity gradient power generation technology, wherein cations and anions contained in the concentrated water supplied between the anion exchange membrane and the bipolar membrane (BPM) of the third cell and between the cation exchange membrane and the bipolar membrane (BPM) of the second cell are converted into acid and base solutions, respectively, diluted, and discharged at a final seawater concentration level.
In Article 7, A seawater desalination and water electrolysis device using salinity gradient power generation technology, further comprising a carbon dioxide mineralization unit that generates carbonates using high-concentration concentrated water discharged between the osmotic membrane and the end plate by the seawater circulation unit.
In Article 9, The above-mentioned fresh water, acid solution, and base solution generating unit supplies the base solution discharged between the cation exchange membrane (CEM) and the anion exchange membrane (AEM) of the second cell to the carbon dioxide mineralization unit, a seawater desalination and water electrolysis device utilizing salinity gradient power generation technology.
In Article 10, The above-mentioned base solution is a sodium hydroxide aqueous solution, a seawater desalination and water electrolysis device utilizing salinity gradient power generation technology.
In Article 8, The above-mentioned fresh water, acid solution, and base solution generating unit is a seawater desalination and water electrolysis device using salinity gradient power generation technology in which the acid solution discharged between the cation exchange membrane (CEM) and the anion exchange membrane (AEM) of the third cell is an aqueous hydrochloric acid solution.

Description

Seawater desalination and electrolysis device using salinity gradient power generation The present invention relates to a salinity gradient power generation technology and apparatus capable of seawater desalination and green hydrogen production without energy consumption. Specifically, it relates to a seawater desalination and water electrolysis apparatus utilizing salinity gradient power generation technology that desalinates seawater by recirculating brine and fresh water without inputting an external energy source, simultaneously produces electrical energy, hydrogen, and oxygen, additionally produces base and acid solutions by recirculating the concentrated water produced by seawater desalination, and discharges the concentrated water with its concentration lowered to seawater levels. Salinity gradient power generation is a system that generates electricity by recovering the energy from the concentration difference generated during the mixing of solutions with different concentrations (e.g., brine, fresh water) in the form of electrical energy. In particular, in a RED (Reverse Electro Dialysis) stack, cations and anions move through the cation exchange membrane and anion exchange membrane, respectively, due to the difference in ion concentration between seawater and freshwater. At this time, a chemical potential difference (membrane potential) is generated between the cation exchange membrane and the anion exchange membrane, and electrical energy is generated by the phenomenon of electron movement through a redox reaction utilizing the potential difference generated by the cation exchange membrane and the anion exchange membrane at the electrodes (positive electrode (anode), negative electrode (cathode)) located at both ends where multiple cation exchange membranes and anion exchange membranes are arranged alternately. As such, RED refers to a power generation method that directly converts chemical energy generated as ions dissolved in brine move to fresh water through cation exchange membranes and anion exchange membranes into electrical energy. Here, in order to enable the RED-type salinity gradient power generation device to exhibit power generation performance applicable in actual field conditions, ranging from a small-scale laboratory level, a stack of existing unit cells is used. On the other hand, seawater desalination utilizing the reverse osmosis phenomenon extracts fresh water by moving ions from a low concentration to a high concentration while supplying pressure higher than the osmotic pressure of seawater; therefore, the seawater concentration increases, and consequently, the cost of the pressure energy that must be supplied rises. Accordingly, in seawater desalination using the reverse osmosis phenomenon, energy costs account for 40% to 50% of the total desalination costs, which is very high, and if concentrated water is discharged into the ocean, it can destroy the marine ecosystem. FIG. 1 is a schematic diagram showing the configuration of a seawater desalination and water electrolysis device using salinity gradient power generation technology according to the first embodiment of the present invention. FIG. 2 is a diagram showing the process flow of a seawater desalination and water electrolysis device using salinity gradient power generation technology according to the first embodiment of the present invention. FIG. 3 is a schematic diagram showing the configuration of a seawater desalination and water electrolysis device using salinity gradient power generation technology according to a second embodiment of the present invention. FIG. 4 is a diagram showing the process flow of a seawater desalination and water electrolysis device using salinity gradient power generation technology according to the second embodiment of the present invention. FIG. 5 is a schematic diagram showing the configuration of a seawater desalination and water electrolysis device using salinity gradient power generation technology according to the third embodiment of the present invention. FIG. 6 is a diagram showing the process flow of a seawater desalination and water electrolysis device using salinity gradient power generation technology according to the third embodiment of the present invention. FIG. 7 is a schematic diagram showing the configuration of a seawater desalination and water electrolysis device using salinity gradient power generation technology according to the fourth embodiment of the present invention. FIG. 8 is a diagram showing the process flow of a seawater desalination and water electrolysis device using salinity gradient power generation technology according to the fourth embodiment of the present invention. Figure 9 is a graph showing experimental results regarding the OCV (open circuit voltage) and energy production of a seawater desalination and water electrolysis device using salinity gradient power generation technology according to an embodiment of the present invention. FIG. 10 is a g