Complex dynamic behaviour during ethylene oxidation on a supported silver catalyst

Abstract

Ethylene oxidation was carried out on a commercial supported silver catalyst (Ag/α-Al2O3) in a spinning-basket catalytic reactor. The progress of the reacting system from initial start-up to final steady state, under certain operating conditions, revealed a complex oscillatory dynamic behaviour. The oscillatory pattern in carbon dioxide concentration in the reactor effluent vanished after a certain time (∼ 100 h) and the system attained steady state. Experiments were carried out to determine the range of reactant (ethylene and oxygen) concentrations wherein oscillations were possible. The dynamic behaviour is explained qualitatively in terms of the competition between reactants and products for adsorption and subsequent reaction on the catalyst surface, occurring simultaneously with slow thermal sintering.