Investigation of 2 liquid phase separation characteristics on the iodine–sulfur thermochemical hydrogen production process

Separation characteristics of 2 liquid phase, sulfuric acid phase and poly-hydriodic acid phase, in HI-H2SO4-I2 solution of the iodine–sulfur (IS) thermochemical hydrogen production process were measured in the wide operation temperature range, from 273 to 368 K in order to establish the closed-cycle operation technology and to improve thermal efficiency of the process. The effects of solution temperature and composition of initial solution on the separation characteristics were investigated. The effect of iodine concentration in the solution on the separation characteristics was also evaluated. The separation characteristics were found to improve with the increase in iodine concentration. Iodine concentration at the point where the solution starts to separate and at the point that iodine saturates, were determined by using measured data.