Fluidized bed catalytic reactor modeling across the flow regimes

Fluidized bed reactor models are generally specific to a single flow regime resulting in ambiguities and discontinuities at the regime boundaries. In practice, only the bubbling, turbulent and fast fluidization regimes are of industrial significance for catalytic reactions. The turbulent fluidizatio n regime is especially advantageous because of improved interphase mass tra nsfer, resulting in improved selectivities and conversions. It is shown tha t some of the difficulties in modeling can be resolved by means of the prob abilistic-averaging model, recently published by Thompson et al. (1999). Th is model interpolates between the Grace (1984) two-phase bubbling bed model at low velocities and single phase axially dispersed flow for fully establ ished turbulent fluidization conditions, leading to improved predictions of conversion and selectivity for catalytic fluidized bed reactors operated a t flow rates covering the full range between bubbling and fully turbulent f luidization. An analogous approach should be useful for beds operated at hi gher gas velocities as fast fluidization conditions are approached.