Thermogravimetry is proposed for studying the alumina catalyst regeneration deactivated by coke, after being used in the transformation of styrene in a fixed bed continuous flow reactor. The model-free kinetic approach has been applied to data for thermal oxidation of carbonaceous deposits on the catalyst. The activation energy (E) was calculated as a function of conversion (alpha) and temperature (T), by using Vyazovkin model-free kinetic method, allowing to estimate time required to remove coke for a given temperature.