Two dimensional fluidised bed reactor: Performance of a novel multi-vortex distributor

Abstract

The influence of the distributor configuration on interphase mass transfer, gas axial dispersion and bubble size was studied in a pseudo 2-D fluidised bed reactor for two types of distributor configurations; a novel multi-vortex (MV) distributor with tubes directed vertically and horizontally at different heights and a standard perforated plate distributor (baseline). The linear inlet velocity ( U 0) ranged between 0.1 m/s and 0.35 m/s, with air as fluidising medium at ambient conditions. The ozone decomposition reaction over Fe 2O 3 impregnated FCC catalyst was used as an indirect measure for the performance of the FBR and it was found that the MV distributor causes a significant improvement (15% average) in the conversion efficiencies at all velocities tested. Bubble size measurements (using two separate techniques) indicated larger bubbles for the MV distributor, while the visual bubbling to turbulent transition boundary ( U c ) for the MV distributor was found to be lower than the baseline distributor. The interphase bubble-emulsion mass transfer was quantified using the model derived by Thompson et al. [32] and was found to be 52% higher for the MV distributor than the baseline distributor. In addition the MV distributor exhibited near plug flow characteristics at velocities exceeding U c , while this was not the case for the baseline distributor.