Abstract (EN):
Ni-hydrotalcite-based dual function materials (DFMs) have been prepared and applied for the combined CO2 capture and methanation in a single reactor. The materials have been synthesized with different chemical properties (by partial substitutions of Mg with Ni, by changing the M2+/M3+ molar ratio - i.e., the (Ni2++Mg2+)/ Al3+ ratio, and by impregnation with Cs (R-.110 wt%)) and the effect of reduction temperature on their cyclic performance was studied. After calcination, the materials were reduced at increasing temperatures, from 400 degrees to 600 degrees C. The cyclic operation started with the capture of CO2 from a 15% CO2/N2 stream (feeding for 20 min), followed by the methanation stage with pure H2. The Cs-promoted sample reduced at 450 degrees C featured a CO2 sorption capacity of 0.48 molCO2 center dot kgcDFM -1 and produced ca. 0.33 molCH4 center dot kgcDFM-1 . Its good performance was associated to a higher number of medium and strong basic sites. The sample containing the highest M2+/M3+ molar ratio (R-.13) exhibited the highest selectivity towards methane (R-.1 100%) and fastest methanation kinetics.
Idioma:
Inglês
Tipo (Avaliação Docente):
Científica
Nº de páginas:
15