Alkali metal hydroxide generation system and the method therefor

A method of producing alkali metal hydroxide, molecular halogen, and hydrogen from an alkali halide anolyte in solution with a transition metal halide complex, and an aqueous alkali metal hydroxide catholyte, comprising:

• using solar photolytic energy to excite a transition metal halide complex in solution with said anolyte, causing a metal ion-ligand to be photochemically reduced to a lower oxidation state, and halide ions to be oxidized to molecular halogen;
• continuously removing said molecular halogen from the presence of said photolytic reaction;
• recovering solar thermal energy from said solution of transition metal halide complex and anolyte;
• using electrical energy to electrolyze said photochemically reduced, transition metal halide complexes in solution with said anolyte, causing said metal ion-ligand to be electrolytically oxidized to a higher oxidation state of that species, water to be reduced to molecular hydrogen and hydroxide ions in said catholyte, and producing said alkali metal hydroxide;
• separating said molecular hydrogen from said catholyte;
• and
• utilizing said solar thermal energy to evaporate water from said catholyte, producing steam and a concentrated aqueous solution of alkali metal hydroxide.

A solar energy deposition system comprising:

• a transition metal halide complex in solution with an alkali metal halide
• means for using solar photolytic energy to excite said transition metal halide complex in solution with an alkali halide, causing a metal ion-ligand to be photochemically reduced to a lower oxidation state, and halide ions to be oxidized to molecular halogen;
• means for using solar thermal energy to heat said solution;
• and
• means for continuously removing said molecular halogen from the presence of said photolytic reaction;
• whereby said alkali halide solution comprises an anolyte.

A system for producing alkali metal hydroxide, molecular halogen, and hydrogen from an alkali halide anolyte in solution with a transition metal halide complex, and an aqueous alkali metal hydroxide catholyte, comprising:

• a transition metal halide complex in solution with said anolyte
• means for using solar photolytic energy to excite said transition metal halide complex in solution with said anolyte, causing a metal ion-ligand to be photochemically reduced to a lower oxidation state, and halide ions to be oxidized to molecular halogen;
• means for continuously removing said molecular halogen from the presence of said photolytic reaction;
• means for recovering solar thermal energy from said solution of transition metal halide complex and anolyte;
• means for using electrical energy to electrolyze said photochemically reduced, transition metal halide complex in solution with said anolyte, causing said metal ion-ligand to be electrolytically oxidized to a higher oxidation state of that species, water to be reduced to molecular hydrogen and hydroxide ions in said catholyte, and producing said alkali metal hydroxide;
• means for separating said molecular hydrogen from said catholyte;
• and
• means for utilizing said solar thermal energy to evaporate water form said catholyte, producing steam and a concentrated aqueous solution of alkali metal hydroxide.