Dense ceramic membranes based on mixed ionic-electron conductors (MIEC) have promising applications in H2 production at T > 600 °C from low-quality gas mixtures (e.g. from biomass). These materials incorporate hydrogen into their lattice as charge protonic defects which means that, theoretically, they are 100% selective towards hydrogen separation. Furthermore, thanks to the properties of these oxides (i.e. working temperatures, durability) this kind of membranes can be integrated in membrane reactors, thus combining reaction/separation in a single industrial unit. Recently, BaCe0.65Zr0.20Y0.15O3-? (BCZ20Y15) and Ce0.85M0.15O2-? (M = Y and Gd) dual-phase membranes were explored by our group [1] reaching hydrogen permeability values among the highest ever reported for bulk MPEC membranes. The highest permeation flux was attained for the 50:50 volume ratio BCZ20Y15 and Ce0.85Gd0.15O2-? membrane, reaching values of 0.27 mL·min-1·cm-2 at 755°C and 2.40 mL·min-1·cm-2 at 1040°C. However, long term stability and degradation mechanisms are critical issues for these systems. The operating conditions in membrane reactors are really challenging: in fact, the gas mixture can contain many contaminants like CO, CO2, and sulphides. In these conditions, undesired phenomena such as structural changes, cation diffusion or chemical reactions could occur damaging the membranes transport performances and mechanical stability. In the present study the sulfur tolerance of BCZ20Y15-GDC15 composite membrane in reducing atmosphere were evaluated by means of different analytical methods, including X-ray diffraction, SEM and impedance spectroscopy. [1] E. Rebollo, C. Mortalò, S. Escolástico, S.Boldrini, S. Barison, J. M. Serra, and M. Fabrizio, Energy and Environmental science 8, 3675-3686, (2015)
Evaluation of the sulfur tolerance behaviour of BaCe0.65Zr0.20Y0.15O3-d-Ce0.85Gd0.15O2-d ceramic membranes for hydrogen separation
E Rebollo;M Fabrizio
2017
Abstract
Dense ceramic membranes based on mixed ionic-electron conductors (MIEC) have promising applications in H2 production at T > 600 °C from low-quality gas mixtures (e.g. from biomass). These materials incorporate hydrogen into their lattice as charge protonic defects which means that, theoretically, they are 100% selective towards hydrogen separation. Furthermore, thanks to the properties of these oxides (i.e. working temperatures, durability) this kind of membranes can be integrated in membrane reactors, thus combining reaction/separation in a single industrial unit. Recently, BaCe0.65Zr0.20Y0.15O3-? (BCZ20Y15) and Ce0.85M0.15O2-? (M = Y and Gd) dual-phase membranes were explored by our group [1] reaching hydrogen permeability values among the highest ever reported for bulk MPEC membranes. The highest permeation flux was attained for the 50:50 volume ratio BCZ20Y15 and Ce0.85Gd0.15O2-? membrane, reaching values of 0.27 mL·min-1·cm-2 at 755°C and 2.40 mL·min-1·cm-2 at 1040°C. However, long term stability and degradation mechanisms are critical issues for these systems. The operating conditions in membrane reactors are really challenging: in fact, the gas mixture can contain many contaminants like CO, CO2, and sulphides. In these conditions, undesired phenomena such as structural changes, cation diffusion or chemical reactions could occur damaging the membranes transport performances and mechanical stability. In the present study the sulfur tolerance of BCZ20Y15-GDC15 composite membrane in reducing atmosphere were evaluated by means of different analytical methods, including X-ray diffraction, SEM and impedance spectroscopy. [1] E. Rebollo, C. Mortalò, S. Escolástico, S.Boldrini, S. Barison, J. M. Serra, and M. Fabrizio, Energy and Environmental science 8, 3675-3686, (2015)I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
