Process design simulation of H2 production by sorption enhanced steam methane reforming: evaluation of potential CO2 acceptors

A concept for pure H production with CO capture by sorption enhanced steam methane reforming (SESMR) has been investigated. Conventional steam reforming with CO capture has been used as a base case for comparison. SESMR resulted in competitive thermal efficiencies, which were highly dependent on the CO acceptor material. Thus, CaO and other more novel solid acceptors such as LiZrO, K-doped LiZrO, NaZrO and LiSiO were screened in terms of thermodynamics, kinetics and stability. It was concluded that higher H yields and efficiencies can be obtained for the acceptors that have good ability for removing CO at low partial pressures. The best efficiencies were obtained using CaO as acceptor due to its more favourable thermodynamics and high reaction rates; however, the stability of CaO has to be improved. On the other hand, NaZrO is a promising alternative due to the good kinetics for CO removal and the stability.