Investigation of particle accumulation under electrostatic effects in a circulating fluidized bed riser using CFD simulation and statistical experimental design and analysis

Electrostatic effects influence hydrodynamics in circulating fluidized bed (CFB) risers, particularly particle accumulation near the wall. In this study, a computational fluid dynamics (CFD) model incorporating dynamic electrostatic charge transport is developed and combined with a 2 4 factorial Design of Experiments (DOE) and ANOVA analysis to systematically evaluate the effects of primary air velocity, backflow velocity, particle diameter, and charge density. The model is validated against experimental pressure measurements The results show that the wall-averaged solid volume fraction in the lower riser varies from 0.0361 to 0.1638 across the investigated conditions, while the axial-averaged solid volume fraction increases from 0.0396 to 0.1584 under low gas velocity and large particle conditions. The solids mass flux ranges from 0.197 to 4.545 kg/(m 2 s), indicating that reduced wall accumulation does not necessarily ensure sufficient solids circulation. Primary air velocity is identified as the dominant factor governing accumulation and solids holdup, whereas particle diameter, backflow velocity, and charge density influence particle behavior through inertia, recirculation, and electrostatic interactions. A suitable operating condition is identified that balances low wall accumulation and stable solids circulation. The findings provide practical guidance for controlling particle accumulation in electrostatically influenced CFB systems. • CFD with DoE is used to analyze electrostatics effects on particle accumulation. • Electrostatic interactions enhance particle accumulation near the wall. • Primary air velocity is the most influential operating parameter. • An optimal condition balances low wall accumulation and stable solids circulation.