Prediction of formation of gas-phase bubbles correlated by vortices in the fuel reactor of chemical looping combustion

• The evolution of bubble formation in the fuel reactor was traced.
• A parameter to indicate the bubble formation was proposed.
• An indicator of the occurrence of time-dependent bubbles in the reactor was proposed.
• The occurrence of the bubbles is highly correlated with the local large eddies.

Chemical looping combustion (CLC) as a potential CO2 capture technology has been considered as a promising and likely alternative to traditional combustion technology to mitigate the CO2 emission due to its prosecution of CO2 sequestration at a low cost. Although a number of studies on the hydrodynamic behaviours of the CLC process in fuel reactor have been documented in the open literature, there have been rare studies on the correlation between the bubble formation and the local particulate volume fraction. This paper aims to investigate the CLC process in a fuel reactor using the CFD modelling, coupled with the heterogeneous reactions, the hydrodynamics and reaction kinetics occurring in the fuel reactor. A parameter correlating the occurrence of bubble and dynamic properties is proposed. The parameter may be acted as an indicator of time-dependent bubble evolution with a potential to be adopted in the CLC for controlling the bubbling phenomena since the occurrence of the bubbles at specific positions is highly correlated with the local large eddies embedded in the flow. The results obtained clearly indicate that the CFD model developed in the current study reasonably forecasts the hydrodynamic behaviours and important phenomena observed in the fuel reactor.