Simulation study about the effect of pressure on purification of HSO and HIx phases in the iodine-sulfur hydrogen production cycle

Wang, L.*; Imai, Yoshiyuki  ; Tanaka, Nobuyuki ; Kasahara, Seiji  ; Kubo, Shinji  ; Onuki, Kaoru; Chen, S.*; Zhang, P.*; Xu, J.*

Optimization of purification operation of the Bunsen reaction products, HSO phase and HIx phase, is one of the problems for industrialization of the thermochemical hydrogen production iodine-sulfur process. HI impurity is contained in HSO phase, and HSO impurity is in HIx phase: these impurities should be removed by purification. Effect of pressure on purification of these phases was simulated as an investigation of the operation by a chemical process simulator ESP with a thermodynamic database based on the Mixed Solvent Electrolyte model. The simulation was of the reaction equilibrium and phase equilibrium. As the result of the simulation in the range of 0.2-6 bar, effective removal of impurities and suppression of undesirable side reactions were suggested in the purification of HSO phase at below atmospheric pressure. On the other hand, advantageous pressure in the viewpoint of equilibrium was not found in purification of HIx phase.