Composite catalytic membrane reactor analysis for the water gas shift reaction in the tritium fusion fuel cycle

A mathematical model has been developed to analyze the behavior of a composite or integrated membrane—fixed bed tubular reactor by considering the catalytic reaction of water with carbon monoxide. Such a reaction is a typical example of an equilibrium controlled reaction, where the conversion is enhanced when one of the products (i.e. the hydrogen) is removed selectively from the reactor. The application considered for such a reactor concept is that of tritium recovery from the solid blanket purge gas and/or from the plasma exhaust gas of a fusion reactor, where a small number of process components, modularity and continuous operations are required. The analysis has been performed taking into account that parameters such as the hydrogen gas diffusion coefficient, film mass transfer resistance and gas linear velocity are not constant along the reactor axis. In an adiabatic reactor, the gas specific heat, temperature and the kinetic parameters are not constant. For this reason, the reactor has been assumed as a series of tubular catalytic membrane reactors. The results show that, with proper optimization, it is possible to achieve very high conversion.