Particle transport and deposition in the hot-gas filter vessel at Wilsonville

Abstract

Particle transport and deposition in the Wilsonville hot-gas filter vessel is studied. The filter vessel contains a total of 72 filters, which are arranged in two tiers. These are modeled by six upper and one lower cylindrical effective filters. An unstructured grid of 296,781 cells generated by GAMBIT is used in the simulations. The Reynolds stress model of FLUENT™ (version 5.0) code is used for evaluating the gas mean velocity and root mean-square fluctuation velocities in the vessel. The particle equation of motion includes the drag, the gravitational and the lift forces. The turbulent instantaneous fluctuation velocity is simulated by a filtered Gaussian white-noise model provided by the FLUENT code. The particle deposition patterns are evaluated, and the effect of particle size is studied. The particle deposition pattern inside the vessel is qualitatively compared with those observed in the physical plant at Wilsonville. In addition, the effect of turbulence dispersion, the lift force and the gravitational force are analyzed. The results show that some ash particles deposit on the tubesheet/shedroof and the central post areas. Furthermore, the deposition pattern depends on particle size, and turbulence dispersion plays an important role in transport and deposition of particles in the vessel. The gravitational force affects the motion of large particles, but has no effect on the transport and deposition of small particles.