Vít Orava, Charles University in Prague, Faculty of Mathematics and Physics, Prague, Czech Republic ZHAW Zürich University of Applied Sciences, Institute of Computational Physics, Winterthur, Switzerland Joint work with Ondrej Soucek and Peter Cendula We investigate modelling of fluidized bed reactor which, in presence of platinumbased (solid) catalytic particles, decomposes liquid formic acid and produces gaseous mixture of carbon dioxide and hydrogen. We treat the system as a mixture in a control volume where we distinguish partial densities and velocities sharing one thermal field. First of all, we consider four constituents, namely formic acid (FA), Platinum micro-pellets (Pt), carbon dioxide (CO2) and hydrogen (H2). Secondly, we reduce the four-constituents model to a binary mixture model of liquid phase (Pt + FA) and gaseous phase (CO2 + H2) which forms bubbles. Liquid phase is considered as non-Newtonian fluid satisfying compresible Navier- Stokes equation with temperature-dependent density and viscosity modelled by Boussinesq approximation and Williams-Landel-Ferry model. Physical interaction between the bubbles and liquid is modelled under equilibrium assumption by the pressure-drag balance. Chemical rates satisfy mass-action law and undergo Arrhenius kinetics. Simulations were performed in COMSOL Multiphysics.