(299f) Improving the Efficiency of the Sulphur Iodine Thermochemical Cycle for Hydrogen Production Using Membrane Separations

The sulphur iodine thermochemical cycle is a promising method for hydrogen production; however current calculations of process efficiency give low results leaving scope for improvement. This paper investigates the application of membrane separations to the HIx processing stage of the cycle, with a view to improving the efficiency. Simulations have been performed, indicating the potential benefits of dewatering the HIx prior to the reactive distillation column. The membrane performance requirements have also been investigated. An experimental programme has been carried out, assessing the applicability of Nafion® membranes for water separation by pervaporation. Flux and selectivity data are presented for HI and HIx solutions, showing the feasibility and practicability of applying the membrane. Experimental flux measurements as a function of temperature, feed concentration and permeate side pressure are reported. The fluxes obtained demonstrate that the separation is feasible; though a higher flux is desirable to reduce the membrane area required. Separation factors are found to be extremely high, with almost pure water permeating through the membrane.