A two-phase compartments model for the selective oxidation of n-butane in a circulating fluidized bed reactor

A phenomenological model for the partial oxidation of n-butane to maleic anhydride (MAN) in a gas–solid riser reactor is proposed. The model captures the main transport–kinetic interactions at both the particle and reactor scale. Two different kinetic models from the literature that either include or neglect the role of solid-state diffusion of oxygen in the catalyst bulk are compared in terms of their impact on overall reactor performance. The use of computational fluid dynamics (CFD) as a means of defining a macroscopic cell-type model for describing the flow patterns in an industrial-scale gas–solids riser is also described. Predictions for the conversion of n-butane and yield of MAN are presented as a function of selected operating variables, and the impact of the variable model parameters on the predictions is briefly assessed. It is shown that the predictions are particularly sensitive to the kinetic model. The relative importance of the interactions between the chemical kinetics and the hydrodynamics is also highlighted.