Kinetic Model of Catalytic Steam Gasification of 2-Methoxy-4-Methylphenol Using 5% Ni–0.25% Ru/γAl₂ O₃ in a CREC-Riser Simulator

Hydrogen is an energy vector with a great potential due its ample range of applications and clean combustion cycle. Hydrogen can be produced through biomass steam gasification, with novel catalysts being of significant value to implement this process. With this goal in mind, in the present study, 5 wt % Ni/γAl₂ O₃ promoted with 0.25 wt % Ru was synthesized and characterized. It is assumed that ruthenium facilitates hydrogen transfer to nickel oxide sites, promoting a hydrogen spillover effect, with the H₂ adsorbed on Ru being transported to Ni sites. To describe chemical changes, the present study considers a kinetic model involving Langmuir–Hinshelwood-based rate equations, as a sum of independent reactions, with this being applied to the steam gasification of 2-methoxy-4-methylphenol (2M4MP). This tar biomass surrogate was studied in a fluidized CREC (Chemical Reactor Engineering Centre) Riser Simulator reactor, at different reaction times (5, 20 and 30 s.) and temperatures (550^◦ C, 600^◦ C and 650^◦ C). The proposed kinetics model was fitted to the experimentally observed H₂, CO₂, CO, CH₄ and H₂ O concentrations, with the estimated pre-exponential factors and activation energies being in accordance with the reported literature data. It is anticipated that the postulated model could be of significant value for the modeling of other biomass conversion processes for hydrogen production using other supported catalysts.