Sizing of a washcoated reactor for the catalytic oxidation of propylene to acrolein on a solid bismuth/molybdate catalyst

Abstract

Catalytic oxidation of propylene to acrolein is usually performed in a multi-tubular fixed bed catalytic reactor at industrial scale. Nevertheless, the production of side products is not optimal as well as the use of molten salt to cool the reactants. This is mainly due to heat transfer issues resulting of the high exothermicity of the reactions. This paper deals with the reactor intensification for the propylene oxidation on a solid bismuth/molybdate catalyst. A simple but robust power law kinetic model, based on the recent published literature, is first proposed, and kinetic parameters are identified by comparison between experiments performed on an isothermal micro fixed bed catalytic reactor and simulations obtained from a pseudo-homogeneous reactor model. The determined parameters are in good agreement with published ones. This kinetic model is then used for the design of an intensified heat-exchanger reactor (HEX reactor). This device consists in several reactive catalyst washcoated channels alternatively distributed with coolant channels. Three performance parameters (acrolein yield, propylene conversion and maximal temperature elevation) are defined, and their variations against process parameters are determined in order to size the HEX reactor and to identify optimal process conditions, for a given feed flow rate.