Development of biogas reforming Ni-La-Al catalysts for fuel cells

In this work, the results obtained for Ni-La-Al catalysts developed in our laboratory for biogas reforming are presented. The catalyst 5% Ni/5% La2O3-gamma-Al2O3 has operated under kinetic control conditions for more than 40 h at 700 degrees C and feeding CH4/CO2 ratio 1/1, similar to the composition presented in biogas streams, being observed a stable behaviour. Reaction parameters studied to evaluate the catalyst activity were H-2/CO and CH4/CO2 conversion ratio obtained. On the basis of a CH4 conversion of 6.5%, CH4/CO2 conversion ratio achieved 0.48 and H-2/CO ratio obtained was 0.43. By comparison of experimental results to equilibrium prediction for such conditions, is detectable a lower progress of reverse water gas shift reaction. This fact increases the H-2/CO ratio obtained and therefore the hydrogen production. The higher H-2/CO and a CH4/CO2 conversion ratio in comparison to CH4 one close to equilibrium is due to the carbon deposits gasification which avoids catalyst deactivation. A thermodynamic analysis about the application of dry and combined methane reforming to hydrogen production for fuel cells application is presented. Data obtained by process simulation considering a Peng-Robinson thermodynamic model, allows optimizing process conditions depending on biogas composition. (C) 2007 Elsevier B.V. All rights reserved.