Thermochemical water splitting through direct Hi-decomposition from H2O/HI/I2 solutions

Abstract Sulfur/iodine cycles have a considerable potential for thermochemical hydrogen production. GA Inc. have investigated these cycles for many years. They have been able to demonstrate the feasibility of such cycles and evaluated first chemical engineering flowsheets. The HI concentration and decomposition seems to be the most expensive and energy consuming step. Therefore, an alternative has been developed at the Institute for Technical Thermodynamics in Aachen, in which HI is decomposed directly from liquid H2O/HI/I2 solution under high pressure and temperature. After thermodynamic correlations for the phase equilibrium in the quaternary mixture of H2O/HI/I2/H2 have been established, a separation column could be designed and theoretically evaluated.