Methods for recycling carbonate byproducts in a hydrogen producing reaction
A process for producing hydrogen gas from a reaction of an organic substance and a base with a recycling of a carbonate or bicarbonate by-product and a regeneration of the base. In one embodiment, reaction of an organic substance and a base produces hydrogen gas and a metal carbonate. The instant invention provides recycling of the metal carbonate by-product.
1 . A process for producing hydrogen gas comprising the steps of
reacting an organic substance with a metal hydroxide producing hydrogen gas and a metal carbonate;
recovering said metal hydroxide from said metal carbonate; and
recycling said metal hydroxide to said step of reacting an organic substance with a metal hydroxide.
2 . The process of claim 1 , wherein said step of recovering said metal hydroxide comprises recausticization.
3 . The process of claim 2 , wherein said step of recausticization comprises the steps of:
a) decarbonization of said carbonate to form an intermediary product and CO 2 gas; and
b) hydrolysis of said intermediary product to form said metal hydroxide.
4 . The process of claim 3 , wherein said step of decarbonization of said carbonate includes reacting said carbonate with a decarbonization agent.
5 . The process of claim 4 , wherein said step of hydrolysis of said intermediary product forms said metal hydroxide and reforms said decarbonization agent.
6 . The process of claim 4 , wherein said recausticization is direct causticization and said decarbonization agent is insoluble in alkaline solution.
7 . The process of claim 6 , wherein said decarbonization agent is a titanium oxide.
8 . The process of claim 6 , wherein said decarbonization agent is a manganese oxide.
9 . The process of claim 6 , wherein said decarbonization agent is an iron oxide.
10 . The process of claim 4 , wherein said recausticization is autocausticization and said decarbonization agent is soluble in alkaline solution.
11 . The process of claim 10 , wherein said decarbonization agent is a borate salt.
12 . The process of claim 10 , wherein said decarbonization agent is a phosphate salt.
13 . The process of claim 10 , wherein said decarbonization agent is a silicate salt.
14 . The process of claim 10 , wherein said decarbonization agent is an aluminate.
15 . The process of claim 4 , wherein said recausticization is thermal decomposition causticization and said decarbonization agent is heat.
16 . The process of claim 1 , wherein said metal of said metal hydroxide is one or more metals from the group consisting of Na, K and Li.