(224d) Measurements of the Simultaneous Solubility of Oxygen and Sulphur Dioxide in Water for the Hybrid Sulphur Thermochemical Cycle

In recent years, the HyS process (formerly known as The Westinghouse process) has emerged as one of the top two routes for the thermochemical manufacture of Hydrogen from water. The work considered here focuses on the oxygen separation stage of the process where, in order for a science based design approach to be taken, thermodynamic data are required for multicomponent phase equilibrium relationships between water, sulphur dioxide and oxygen; H2O-SO2-O2. A method of making flash calculations, useful in the separation equipment design, has been proposed and coded into Mathematica®. Further, a vapour liquid equilibrium still has been designed and built to make measurements of the multicomponent solubility of sulphur dioxide and oxygen in water. Preliminary results of total sulphur dioxide dissolved in water show very good agreement with literature data. At 24.6 ºC and a total pressure of 0.249 atm the solubility was found to be 0.215 mol SO2 / kg H2O and at a total pressure of 1.93 atm and 39.1 ºC the solubility was 1.54 mol SO2 / kg H2O.