Numerical study of the effect of the inlet gas distributor on the bubble distribution in a bubbling fluidized bed

Abstract

Gas bubble distribution is considered one of the most critical factors affecting the Industrial Fluid Coking™ process since it influences the formation of wet agglomerates that causes fouling in the stripper section. A multi-phase Eulerian–Eulerian two-fluid method (TFM) coupled with the kinetic theory of the granular flow (KTGF) was used to investigate the hydrodynamics of a bubbling fluidized bed; the goal is to increase the flow of gas bubbles into the first half of the jet cavity formed when liquid is sprayed into the fluidized bed, thus reducing the formation of wet agglomerates. The numerical simulations under different superficial gas velocities, different gas distributor geometries, and different gas distributor inclined angles were carried out. The results showed that the predicted bubble distributions at the injection level under the lab and commercial operating conditions are similar although the particles and gases are different under those two operating conditions. More gas bubbles can be directed to the first half of the jet cavity by either increasing the gas superficial velocity (directing around 20% more gas to the specified area) or using the proposed new gas distributor (directing around 30% more gas to the specified area). The effect of the inlet gas distributor configuration on the bubble distribution is much more substantial when the inclined angle of the gas distributor is large.