Electrostatic effects on hydrodynamics in the riser of the circulating fluidized bed for polypropylene

Abstract

AbstractElectrostatic potential in the multizone circulating fluidized bed (CFB) reactor for polypropylene is measured even larger than 1,000 V. In this article, electrostatic effects on hydrodynamics in the riser of CFBs were studied via experiment and computational fluid dynamic simulation. Experimental results showed electrostatics increased solids holdup in the riser for more than 20% in fast fluidization. Using measured charge densities as electrostatic model parameters, electrostatic effects were simulated by two‐fluid model coupled with electrostatics accurately. The relative deviation between measured and simulated solids holdup was 3.53% at 5.68 m/s, which was the first time that this mode was verified quantitatively. Further analysis of simulation results demonstrated the mechanism of electrostatic effects was that the electrostatic forces increased the radial particle velocity and induced particle accumulation near the wall, leading to the increase of solids holdup. These electrostatic effects are more significant in the dense‐phase region, which require special care.