Experimental study of the vapour-liquid equilibria of HI-I2-H2O ternary mixtures

In the framework of the massive production of hydrogen using the sulphur-iodine thermochemical cycle, the design of the reactive distillation column, chosen by CEA for the HIx section, requires the knowledge of the partial pressures of the gaseous species (HI, I2, H2O) in thermodynamic equilibrium with the liquid phase of the HI-I2-H2O ternary mixture in a wide range of concentrations up to 270°C and 50 bar. The experimental devices which enable the measurement of the total pressure and concentrations of the vapour phase (and thus the knowledge of the partial pressures of the different gaseous species) for the HI-I2-H2O mixture in the 20-250°C range and up to 35 bar are described.