A Thermo-Physical Model for Iodine–Sulfur Cycle for Hydrogen Production

In closed loop Iodine-Sulfur (I-S) process for hydrogen production, sulfuric acid and HI are formed in Bunsen reaction at about 353-393 K which needs to concentrate before decomposing to sulfur trioxide [1]. This concentration and reaction involve many ionic species whose thermodynamic properties including phase behavior, speciation, heat capacity of these complex sulfuric acid and HI systems in the different temperature ranges (up to 1173 K in case of sulfuric acid system) need to be determined. However, this task still a vital challenge to researcher due to chemical speciation, non-ideal azeotrope formation and thermal dissociation of sulfuric acid and HI acid [2-3]. Henceforth, this work is an attempt to develop algorithm based eNRTL model to predict the thermodynamic behaviour including chemical speciation, phase equilibria and enthalpy of the sulfuric acid and HI acid systems individually