Applicability of inorganic membranes for improving the sulfur-iodine process for the production of hydrogen using nuclear energy

The Sulfur-Iodine (SI) thermochemical process is the leading candidate worldwide for production of hydrogen (H₂) using heat from nuclear energy. This process thermocatalytically cracks water yielding hydrogen and oxygen. The SI process consists of a series of chemical reactions where all the chemicals are recycled in the process except for water. The SI process is efficient, scalable to large sizes, and uses no expensive chemical reagents; however, it has one major disadvantage: high operating temperatures (800 to 1000 C). The high-temperature chemical reaction in this cycle is the thermal decomposition of sulfuric acid. There is a potential to lower the peak temperature by 200+ C if the high-temperature decomposition products of sulfuric acid, O₂, H₂O, and SO₂, can be separated from SO₃ using an inorganic membrane. First generation membranes have been fabricated from materials selected based on literature stability data. Results on the stability of these membranes under simulated operational conditions and data showing the potential to separate the product gases from SO₃ will be presented.