Experimental study on side-reaction occurrence condition in the iodine–sulfur thermochemical hydrogen production process

In iodine–sulfur thermochemical hydrogen production process (IS process), side-reactions from HI, H2SO4 and I2 mixture solution were investigated experimentally in operating temperature ranges, from 295 to 368 K. The effects of the reaction temperature, acid concentration, iodine concentration and the ratio of the amount of H2SO4 to that of HI on the sulfur formation are discussed. The quantitative reaction analysis was also conducted for certain experimental conditions. The results of mass balance during the reaction showed that the sulfur formation side-reaction appeared to predominate in comparison with the hydrogen sulfide formation side-reaction. By using experimental data, the desirable closed cycle operation conditions for IS process were clarified.