Intensified Conversion of Natural Gas Using Proton-Conducting Ceramics

Today, more than 50 million ton of hydrogen is produced annually, predominantly through steam methane reforming (SMR) with subsequent water gas-shift combined with pressure swing adsorption (PSA) for product separation. This technology is, however, not suitable for small scale on-site reforming systems due to high capital costs, moderate energy efficiency and large system size. Further, methane is considered to be an alternative source for synthesis of valuable products currently obtained by crude oil processing. Methane dehydroaromatization (MDA) under non-oxidative conditions over cation-modified zeolites has received considerable attention as a promising route for direct conversion of methane into highly value-added chemicals such as aromatics and hydrogen. The MDA process suffers however from several shortcomings that impose serious limitations for commercialization. The reaction is limited by thermodynamics and fast deactivation of the catalyst on-stream due to accumulation of carbon deposits on the catalyst surface.

For both processes we demonstrate that a galvanically driven catalytic membrane reactor based on a ceramic proton conductor enables process intensification through integration of catalytic reactions, heat management and separation in one process step. A tubular membrane with electrolyte composition BaZr0.7Ce0.2Y0.1O3- (BZCY72) (25-30 μm) on a Ni-BZCY72 support is utilized with Ni and Cu as the anode for SMR and MDA experiments, respectively.