Low energy 4-cell electrochemical system with carbon dioxide gas
A low-voltage, low-energy electrochemical system and method of producing hydroxide ions and/or bicarbonate ions and/or carbonate ions utilizing significantly less than the typical 3V used across the conventional anode and cathode to produce the ions; consequently, carbon dioxide emissions attributable to the present system and method are significantly reduced.
1. An integrated system comprising:
an electrochemical system comprising
a first cell containing a cathode electrolyte, the cathode electrolyte contacting a cathode and comprising a hydroxide,
a second cell containing an anode electrolyte, the anode electrolyte contacting an anode, wherein
the cathode is configured to produced hydroxide ions and hydrogen gas and the anode is configured to absorb hydrogen gas and produce protons without producing a gas on application of a voltage across the anode and cathode,
a third cell separated from the cathode electrolyte by an ion exchange membrane and connected to a source of concentrated salt solution and configured to receive the concentrated salt solution and produce a depleted salt solution,
a fourth cell separated from the second and third cells by ion exchange membranes and configured to produce a concentrated acid solution;
a system configured for absorbing a gas in the cathode electrolyte operably connected to the electrochemical system wherein the gas comprises waste gases of a cement production plant or a power generating plant; and
a material dissolution system operably connected to the electrochemical system and configured to utilize the acid and/or hydroxide in the cathode electrolyte to dissolve a calcium and/or magnesium rich material and produce a divalent cation solution.
2. The integrated system of claim 1 , wherein the waste gas comprises carbon dioxide.
3. The integrated system of claim 2 , wherein the system for absorbing a gas in the cathode electrolyte is configured to produce a carbonate and/or a bicarbonate by mixing the cathode electrolyte, the waste gas and the divalent cation solution.
4. The integrated system of claim 3 , wherein the hydroxide and/or a bicarbonate and/or carbonate comprise calcium and/or magnesium.
5. The integrated system of claim 4 , wherein the
hydroxide in the cathode electrolyte is produced by migrating cations from the third electrolyte into the cathode electrolyte, and the concentrated acid in the fourth electrolyte is produced by migrating protons from the anode electrolyte and anions from the third electrolyte into the fourth electrolyte.
6. The integrated system of claim 5 , wherein the calcium and/or magnesium material comprises a mineral, fly ash or red mud.
7. The integrated system of claim 6 , further comprising a desalination system operatively connected to electrochemical system and configured to produce desalinated water from the salt depleted third electrolyte.
8. The integrated system of claim 7 , further comprising a slurry disposal system operatively connected to the carbonate precipitating system and configured to receive and dispose the precipitated calcium and/or magnesium carbonate and/or bicarbonate in an ocean at a depth where the temperature and pressure are sufficient to keep the slurry stable indefinitely.
9. A method comprising:
receiving a concentrated salt solution and producing a depleted salt solution in a third cell of an electrochemical system by applying a voltage across a cathode contained in a first cell and an anode contained in a second cell of the electrochemical system,
receiving a weak acid solution and producing a concentrated acid solution in a fourth cell of the electrochemical system wherein
the third cell is separated from the first cell containing a cathode electrolyte, the cathode electrolyte comprising a hydroxide and contacting the cathode, and
the fourth cell is separated from the second cell containing an anode electrolyte, the anode electrolyte contacting the anode,
producing hydroxide ions and hydrogen gas at the cathode, and absorbing hydrogen gas and producing protons at the anode without producing a gas at the anode;
absorbing a gas in the cathode electrolyte wherein the gas comprises waste gases of a cement production plant or a power generating plant; and
dissolving a solid material comprising a calcium and/or magnesium rich material with the acid to produce a divalent cation solution.
10. The method of claim 9 , comprising producing a hydroxide and/or a bicarbonate and/or a carbonate with the cathode electrolyte and the divalent cation solution.
11. The method of claim 10 , wherein the hydroxide and/or a bicarbonate and/or a carbonate comprises calcium and/or magnesium.
12. The method of claim 11 , comprising dissolving a waste material comprising a mineral, fly ash or red mud with the acid to produce the divalent cation solution.
13. The method of claim 12 , comprising producing desalinated water from the third electrolyte in a desalination system.
14. The method of claim 13 , comprising disposing the cathode electrolyte comprising precipitated calcium and/or magnesium carbonate and/or bicarbonate at an ocean depth where the temperature and pressure are sufficient to keep the slurry stable indefinitely.