CFD simulation of the hydrodynamics and reaction kinetics of chemical looping combustion process in a fuel reactor

Abstract

Papers presented to the 11th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 20-23 July 2015.A typical CLC unit consists of a circulating fluidised bed as the air reactor and a bubbling fluidised bed as the fuel reactor. A number of studies on the hydrodynamics behaviours of the CLC process in fuel reactor have been documented in the open literature and some are focused on numerical modelling of dynamic processes in the fuel reactors but 3D numerical modelling of the multiphase flow coupled with chemical reaction dynamics in the fuel reactor is still rarely undertaken. This paper aims to investigate the CLC process in a fuel reactor using the 3D-CFD modelling, coupled with the heterogeneous reactions, the hydrodynamics and reaction kinetics of the CLC process in the fuel reactor. A parameter used for relating the timedependent bubble occurance to the local eddies is proposed by correlating the local velocity fluctuation with the pressure fluctuation. The relation between the concentration of gaseous reactants or products and local vortices is also investigated. The results obtained clearly indicate that the CFD modelling conducted in the current study reasonably forecasts the hydrodynamic behaviours and important phenomena observed in the fuel reactor. The parameter correlating the bubble occurabce with local velocity fluctuation may be used in the CLC for controlling the bubbling phenomenon because the occurrence of the bubbles at specific positions is strongly associated with the locally embedded large eddies.