Low-energy electrochemical hydroxide system and method

Abstract

A low-energy method and system of forming hydroxide ions in an electrochemical cell. On applying a low voltage across the anode and cathode, hydroxide ions form in the electrolyte containing the cathode, protons form at the anode but a gas e.g. chlorine or oxygen does not form at the anode.

1 .- 20 . (canceled) 
     
     
         21 . A carbonate precipitating system comprising:
 an electrochemical system comprising an anion exchange membrane separating an anode electrolyte that is in contact with an anode from an intermediate electrolyte; and a cation exchange membrane separating a cathode electrolyte that is in contact with a cathode from the intermediate electrolyte; wherein the cathode is configured to produce a hydroxide in the cathode electrolyte on application of a voltage across the anode and cathode; and wherein   the electrochemical system is operably connected to a reactor configured to mix the cathode electrolyte and a source of waste gas mixed to produce a precipitate comprising a hydroxide and/or a carbonate and/or a bicarbonate.   
     
     
         22 . The carbonate precipitating system of  claim 21 , wherein the reactor is configured to mix the cathode electrolyte and the waste gas with a salt water. 
     
     
         23 . The carbonate precipitating system of  claim 22 , wherein the source of waste gas comprises carbon dioxide from a cement production process, a power generating facility, or a carbon combustion process. 
     
     
         24 . The precipitating system of  claim 23 , wherein the voltage is less than 2.8 V. 
     
     
         25 . The carbonate precipitating system of  claim 24 , wherein the salt water comprises divalent cations. 
     
     
         26 . The carbonate precipitating system of  claim 25 , wherein the precipitate comprises calcium an/or magnesium. 
     
     
         27 . The carbonate precipitating system of  claim 26 , 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. 
     
     
         28 . The carbonate precipitating system of  claim 26 , wherein the cathode is configured to produced hydroxide ions and hydrogen gas, and the anode electrolyte is configured to produce a gas. 
     
     
         29 . The carbonate precipitating system of  claim 28 , wherein the anode electrolyte comprises hydrochloric acid and the cathode electrolyte comprises sodium hydroxide and/or sodium carbonate and/or sodium bicarbonate. 
     
     
         30 . The carbonate precipitating system of  claim 29 , comprising a third electrolyte separated from the cathode electrolyte and the anode electrolyte by one or more ion exchange membranes. 
     
     
         31 . The carbonate precipitating system of  claim 30 , configured to migrate anions from the third electrolyte through an anion exchange membrane into the anode electrolyte, and migrate cations through a cation exchange membrane into the cathode electrolyte. 
     
     
         32 . A CO 2  sequestration system comprising:
 an electrochemical system comprising an anode contacting an anode electrolyte and a cathode contacting a cathode electrolyte, wherein the cathode is configured to produce a hydroxide in the cathode electrolyte with a voltage applied across the anode and cathode; and   a source of industrial waste gas, wherein the source of waste gas comprises a cement production process that emits carbon dioxide, and wherein the electrochemical system and the source of waste gas are operably integrated such that carbon dioxide from the source of waste gas is absorbed into the cathode electrolyte.   
     
     
         33 . The CO 2  sequestration system of  claim 32 , wherein the source of waste gas comprises a power generating facility or a carbon combustion process. 
     
     
         34 . The CO 2  sequestration system of  claim 33 , wherein the cathode electrolyte comprises bicarbonates and/or carbonates. 
     
     
         35 . The CO 2  sequestration system of  claim 34 , wherein the carbonates and/or bicarbonates comprise calcium and/or magnesium. 
     
     
         36 . The CO 2  sequestration system of  claim 35 , wherein the voltage is less than 2.8 V. 
     
     
         37 . The CO 2  sequestration system of  claim 36 , 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. 
     
     
         38 . The CO 2  sequestration system of  claim 37 , wherein the cathode is configured to produced hydroxide ions and hydrogen gas, and the anode electrolyte is configured to produce a gas. 
     
     
         39 . The CO 2  sequestration system of  claim 37 , wherein the anode electrolyte comprises hydrochloric acid and the cathode electrolyte comprises sodium hydroxide and/or sodium carbonate and/or sodium bicarbonate. 
     
     
         40 . The CO 2  sequestration system of  claim 39 , comprising a third electrolyte separated from the cathode electrolyte and the anode electrolyte by one or more ion exchange membranes. 
     
     
         41 . A method comprising:
 producing hydroxide ions in a cathode electrolyte by applying a voltage across a cathode in contact with the cathode electrolyte and an anode in contact with an anode electrolyte; and   mixing the cathode electrolyte with an industrial waste gas such that carbon dioxide in the waste gas is absorbed into the cathode electrolyte.   
     
     
         42 . The method of  claim 41 , wherein the source of waste gas comprises a cement production process, a power generation facility or a carbon combustion process. 
     
     
         43 . The method of  claim 42 , wherein the carbon dioxide is derived from calcining limestone. 
     
     
         44 . The method of  claim 43 , comprising producing bicarbonates and/or carbonates in the cathode electrolyte. 
     
     
         45 . The method of  claim 44 , wherein the carbonates and/or bicarbonates comprises calcium and/or magnesium. 
     
     
         46 . The method of  claim 45 , wherein the voltage is less than 2.8 V. 
     
     
         47 . The method of  claim 46 , comprising producing hydroxide ions and hydrogen gas at the cathode, and absorbing hydrogen gas at the anode and producing protons without producing a gas at the anode. 
     
     
         48 . The method of  claim 47 , comprising producing hydroxide ions and hydrogen gas at the cathode, and a gas at the anode. 
     
     
         49 . A system comprising:
 an electrochemical system configured with an anode contacting an anode electrolyte a cathode contacting a cathode electrolyte to produce hydroxide ions in the cathode electrolyte with a voltage applied across the anode and cathode; and   an absorber operably integrated with the electrochemical system and configured to sequester carbon dioxide from a waste gas by mixing the cathode electrolyte with the waste gas and a salt water.   
     
     
         50 . The system of  claim 49 , wherein the salt water comprises a brine, seawater or brackish water. 
     
     
         51 . The system of  claim 50 , wherein the salt water comprises divalent cations. 
     
     
         52 . The system of  claim 51 , wherein the waste gas comprises waste gases of a cement production process, a power generating facility, or a carbon combustion process. 
     
     
         53 . The system of  claim 53 , wherein the cathode electrolyte comprises a hydroxide and/or a bicarbonate and/or a carbonate. 
     
     
         54 . The system of  claim 54 , wherein the carbonate and/or bicarbonate comprise calcium and/or magnesium. 
     
     
         55 . The system of  claim 55 , wherein the voltage is less than 2.8 V. 
     
     
         56 . The system of  claim 55 , 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. 
     
     
         57 . The system of  claim 55 , wherein the cathode is configured to produced hydroxide ions and hydrogen gas, and the anode is configured to produce a gas. 
     
     
         58 . The system of  claim 56 , wherein the anode electrolyte comprises hydrochloric acid and the cathode electrolyte comprises sodium hydroxide and/or sodium carbonate and/or sodium bicarbonate. 
     
     
         59 . The system of  claim 58 , comprising a third electrolyte separated from the cathode electrolyte and anode electrolyte by one or more ion exchange membranes. 
     
     
         60 . A method comprising:
 configuring an electrochemical system to produce a hydroxide in a cathode electrolyte by contacting an anode with an anode electrolyte and a cathode with a cathode electrolyte and applying a voltage across the anode and cathode; and   sequestering carbon dioxide from a waste gas by mixing the cathode electrolyte with a salt water and the waste gas.   
     
     
         61 . The method of  claim 60 , wherein the salt water comprises a brine, seawater or brackish water. 
     
     
         62 . The method of  claim 61 , wherein the salt water comprises divalent cations. 
     
     
         63 . The method of  claim 62 , wherein the waste gas comprises waste gases from a cement production process, a power generating facility, or a carbon combustion process. 
     
     
         64 . The method of  claim 63 , comprising producing a hydroxide and/or a bicarbonate and/or a carbonate in the cathode electrolyte. 
     
     
         65 . The method of  claim 64 , wherein the carbonates and/or bicarbonates comprises calcium and/or magnesium. 
     
     
         66 . The method of  claim 65 , wherein the voltage is less than 2.8 V. 
     
     
         67 . The method of  claim 66 , comprising producing hydroxide ions and hydrogen gas at the cathode, and absorbing hydrogen gas at the anode and producing protons without producing a gas at the anode. 
     
     
         68 . The method of  claim 66 , comprising producing hydroxide ions and hydrogen gas at the cathode, and a gas at the anode. 
     
     
         69 . An integrated system comprising:
 an electrochemical system comprising an anode contacting an anode electrolyte and a cathode contacting a cathode electrolyte, and configured to produce hydroxide ions in the cathode electrolyte and an acid in the anode electrolyte with an applied voltage across the anode and cathode; and   a mineral-dissolution system operably integrated with the anode electrolyte and configured to produce cations by dissolving a mineral with the acid.   
     
     
         70 . The integrated system of  claim 69 , wherein the acid comprises hydrochloric acid. 
     
     
         71 . The integrated system of  claim 70 , wherein the mineral comprises a mafic mineral. 
     
     
         72 . The integrated system of  claim 71 , wherein the cations comprise calcium ions and/or magnesium ions. 
     
     
         73 . The integrated system of  claim 72 , wherein the voltage is less than 2.8 V. 
     
     
         74 . The integrated system of  claim 73 , 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. 
     
     
         75 . The integrated system of  claim 73 , wherein the cathode is configured to produced hydroxide ions and hydrogen gas and the anode electrolyte is configured to produce a gas. 
     
     
         76 . A method comprising:
 producing hydroxide ions in a cathode electrolyte in contact with a cathode and an acid in an anode electrolyte in contact with an anode with an applied voltage across the anode and cathode; and   produce cations by dissolving a mineral with the acid in a mineral-dissolution system.   
     
     
         77 . The method of  claim 76 , wherein the acid comprises hydrochloric acid. 
     
     
         78 . The method of  claim 77 , wherein the mineral comprises a mafic mineral. 
     
     
         79 . The method of  claim 78 , wherein the cations comprise calcium ions and/or magnesium ions. 
     
     
         80 . The method of  claim 79 , wherein the voltage is less than 2.8 V. 
     
     
         81 . The method of  claim 80 , comprising producing hydroxide ions and hydrogen gas at the cathode, and absorbing absorb hydrogen gas at the anode and produce protons without producing a gas. 
     
     
         82 . The method of  claim 80 , comprising producing hydroxide ions and hydrogen gas at the cathode and a gas at the anode. 
     
     
         83 . A precipitating system comprising:
 an electrochemical system comprising an anode contacting an anode electrolyte, a cathode contacting a cathode electrolyte and configured to produce hydroxide ions in the cathode electrolyte and an acid in the anode electrolyte with an applied voltage across the anode and cathode; wherein   the electrochemical system is operable connected to a precipitator that is configured to produce a cementitous composition by mixing the cathode electrolyte with a salt solution and a waste gas comprising carbon dioxide.   
     
     
         84 . The precipitating system of  claim 83 , wherein the cementitous composition comprises a carbonate and/or a bicarbonate. 
     
     
         85 . The precipitating system of  claim 84 , wherein the cementitous composition comprises calcium and/or magnesium. 
     
     
         86 . The precipitating system of  claim 85 , wherein the cathode electrolyte comprises carbonate ions and/or bicarbonate ions. 
     
     
         87 . The precipitating system of  claim 86 , wherein the source of the waste gas comprises a cement production process, a power generating facility, or a carbon combustion process. 
     
     
         88 . The precipitating system of  claim 87 , wherein the voltage is less than 2.8 V. 
     
     
         89 . The precipitating system of  claim 88 , 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. 
     
     
         90 . The precipitating system of  claim 88 , wherein the cathode is configured to produced hydroxide ions and hydrogen gas and the anode configured to produce a gas. 
     
     
         91 . The precipitating system of  claim 90 , wherein the anode electrolyte comprises hydrochloric acid and the cathode electrolyte comprises sodium hydroxide and/or sodium carbonate and/or sodium bicarbonate. 
     
     
         92 . The precipitating system of  claim 91 , comprising a third electrolyte separated from the cathode electrolyte and the anode electrolyte by one or more ion exchange membranes. 
     
     
         93 . A method comprising:
 configuring an electrochemical system with an anode contacting an anode electrolyte and a cathode contacting a cathode electrolyte, to produce hydroxide ions in the cathode electrolyte with an applied voltage across the anode and cathode; and   producing a cementitous composition by mixing the cathode electrolyte with a salt solution and a waste gas comprising carbon dioxide in a precipitator operably connected to the cathode electrolyte.   
     
     
         94 . The method of  claim 93 , wherein the cathode electrolyte comprises carbonate ions and/or bicarbonate ions. 
     
     
         95 . The method of  claim 94 , wherein the cementitous composition comprises a carbonate and/or a bicarbonate. 
     
     
         96 . The method of  claim 95 , wherein the cementitous composition comprises calcium and/or magnesium. 
     
     
         97 . The method of  claim 96 , wherein the source of the waste gas comprises a cement production process, a power generating facility, or a carbon combustion process. 
     
     
         98 . The method of  claim 97 , wherein the voltage is less than 2.8 V. 
     
     
         99 . The method of  claim 98 , comprising 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. 
     
     
         100 . The method of  claim 99 , comprising producing hydroxide ions and hydrogen gas at the cathode and a gas at the anode. 
     
     
         101 . A system comprising an industrial plant and an electrochemical system configured to absorb a waste gas generated by the industrial plant into a cathode electrolyte of the electrochemical system. 
     
     
         102 . The system of  claim 101 , wherein the industrial plant comprises a power generating plant, a cement producing plant or an ore smelting plant. 
     
     
         103 . The system of  claim 102 , wherein the waste gas comprises carbon dioxide and combustion gases and wherein the electrochemical system is configured to produce an alkaline solution in the cathode electrolyte without generating a gas at an anode in the electrochemical system. 
     
     
         104 . The system of  claim 103 , wherein the alkaline solution comprises a hydroxide and/or a bicarbonate and/or a carbonate. 
     
     
         105 . The system of  claim 104 , wherein the hydroxide and/or a bicarbonate and/or a carbonate comprises calcium and/or magnesium. 
     
     
         106 . The system of  claim 105 , wherein the electrochemical system is configured to produce hydrogen gas at the cathode and consume hydrogen gas at the anode and produce protons in an anode electrolyte in contact with the anode. 
     
     
         107 . The system of  claim 106 , wherein the alkaline solution is produced with a voltage of less than 2.8 V across the anode and cathode. 
     
     
         108 . The system of  claim 107 , further comprising a gas absorber operably connected to the electrochemical system and configured to precipitate a carbonate and/or a bicarbonate by mixing the cathode electrolyte and the waste gas. 
     
     
         109 . The system of  claim 108 , further comprising a mineral-dissolution system operably connected to the electrochemical system and configured to dissolve a material comprising divalent cations with the anode electrolyte. 
     
     
         110 . A method comprising:
 absorbing a waste gas from an industrial plant into a cathode electrolyte in an electrochemical system and producing a hydroxide and/or a bicarbonate and/or a carbonate in the cathode electrolyte.   
     
     
         111 . The method of  claim 110 , wherein the industrial plant comprises a power generating plant, a cement producing plant or an ore smelting plant. 
     
     
         112 . The method of  claim 111 , wherein the hydroxide and/or a bicarbonate and/or a carbonate comprises calcium and/or magnesium. 
     
     
         113 . The method of  claim 112 , wherein the hydroxide and/or a bicarbonate and/or a carbonate comprises calcium and/or magnesium. 
     
     
         114 . The method of  claim 113 , wherein the waste gas comprises carbon dioxide and combustion gases. 
     
     
         115 . The method of  claim 114 , comprising producing hydrogen gas and hydroxide ions at the cathode and consuming a hydrogen and producing protons at the anode without producing a gas at the anode of the electrochemical system by applying a voltage across the cathode and anode. 
     
     
         116 . The method of  claim 115 , comprising directing hydrogen gas produced at the cathode to the anode. 
     
     
         117 . The method of  claim 116 , wherein the voltage is less than 2.8 V. 
     
     
         118 . The method of  claim 117 , comprising producing an acid in the anode electrolyte in contact with the anode and producing a divalent cation solution by dissolving a material with the acid.