Computational and experimental study of electrostatics in gas–solid polymerization fluidized beds

Gas–particle flows are present in many industrial applications such as polymerization, fluid catalytic cracking, chemical vapor deposition, combustion and drying. Particle–particle, particle–wall and gas–particle interactions cause electrostatic charge to form on particles. The motion of charged particles creates an electric field, affecting the hydrodynamics in reactors such as polymerization fluidized beds and fluid catalytic crackers (Hendrickson, 2006). In this work, a combined multi-fluid and electrostatic model previously developed in Rokkam et al. (2010) is used to simulate laboratory-scale experiments on electrostatics in gas–solid fluidized beds conducted by Sowinski et al. (2010). The fluidized-bed experiments were operated in two flow regimes, bubbling and slug flow. Charge-to-mass ratio (q/m) measured in the experiments was used as an input to the computational fluid dynamic (CFD) electrostatic model. Particle-phase segregation from CFD simulations with electrostatic forces compared well with experimental measurements and observations.

Mean volume fraction of wall particles in bubbling-bed simulations with refined grid (a) charged, (b) left wall near the distributor, (c) left wall near the distributor with different ranges.Figure optionsDownload high-quality image (199 K)Download as PowerPoint slideHighlights
► A Faraday cup technique is used to study the electrostatics in fluidized-bed.
► The measured particle charge is used as an input to the multiphase CFD model.
► The CFD multiphase model predicted the segregation observed in experiments.