Methane catalytic combustion over Pd/Al2O3 in presence of sulphur dioxide: development of a regeneration procedure

Five different procedures (treatments with hydrogen, nitrogen, wet and dry air, and under vacuum) were tested for the regeneration of a partially deactivated alumina-supported Pd catalyst, used for the catalytic incineration of methane in presence of SO2. The efficiency of these processes was evaluated considering the temperatures at which both, the catalysts deactivation, and the regeneration processes, took place. As general trend, hydrogen treatment is the best regeneration procedure, followed by treatment with wet air, whereas high deactivation temperatures lead to less efficient regeneration. The efficiency of the regeneration was observed to increase as regeneration temperature increases. These trends are discussed according to the results obtained in the characterisation of deactivated catalyst samples using TPR, TPO and TPD.