Improvement of sulphur dioxide yield from the sulphuric acid thermal decomposition process by membrane separation.

This work investigates the feasibility of applying high temperature oxygen
separation to the sulphuric acid decomposition process, a step used in
large scale hydrogen production processes currently under development.
Porous and dense membranes are both considered. Equilibrium calculations
show yttria-stabilised zirconia (YSZ), combined with platinum electrodes,
to be a candidate membrane. Process simulations show the potential
sulphur dioxide yield increases that could be achieved through the use
of a high temperature oxygen separation membrane in two different configurations.
Bespoke experimental apparatus was designed, procured and
assembled in order to investigate the oxygen flux through YSZ membranes
in the presence of sulphur dioxide, during external voltage application. Experiments
were performed in the 700 - 900°C temperature range. Results
show that oxygen permeation through YSZ membranes occurs under these
conditions. A decrease in oxygen permeation with time was observed and
attributed to sulphur dioxide adsorption on to the platinum electrodes. Future
work would concentrate on using variable applied voltages to reduce
this performance decrease.