A new spouted bed reactor non-isothermal modelling is developed, in which the spout, the fountain, and the annulus region are taken into account. The flow pattern is based on the streamtube formulation with a special approach for flat-bottomed reactors. Heat transfers are included by means of an heterogeneous approach. The parameters influence study shows the resolution scheme stability. The model results are compared with experimental data from literature for CO catalytic oxidation on alumina-supported Co3O4. Accurate predictions of bed temperature level and conversion are achieved.