Numerical Simulations for Performance Optimization of Circulating Fluidized Bed Calciner

Large-scale circulating fluidized bedsCirculating fluidized bed are used as calciners in aluminaAlumina refineries. AluminaAlumina product quality (loss on ignition, LOI) depends on heat transferHeat transfer effects and particle residence time in the calciner. The operational parameters of fluidization such as air and fuel flow rates along with pressure drop across the furnaceFurnace are sensitive to changes in production rate. In this context, Lagrangian discrete phase model is used to simulate gas–solid hydrodynamics and visualize the thermal profile. The model is validated against the measured calciner temperature. SimulationsSimulation are performed for various flow rates of hydrate feed, air and fuel. The results revealed a strong influence of fluidization air flow rate and its split to primary and secondary air on the overall thermal profile. Therefore, an optimum ratio of primary-to-secondary air flow rate was deduced to achieve the desired thermal profile for varied production rates.