Hot-gas flow and particle transport and deposition in an industrial filtration system are studied. The special example of the Siemens-Westinghouse filter vessel at the Power System Development Facility at Wilsonville, Alabama is treated in detail. This tangential flow filter vessel contains clusters of 91 candle filters, which are arranged in two tiers. The upper tier containing 36 candle filters is modeled by six equivalent filters. Seven equivalent filters are used in the computational model to represent the 55 candle filters in the lower tiers. The Reynolds stress turbulent model of FLUENT(TM) code is used, and the gas mean velocity and root mean square fluctuation velocities in the filter vessel are evaluated. The particle equation of motion used includes drag and gravitational forces. The mean particle deposition patterns are evaluated and the effect of particle size is studied. The computational results indicate that large particles of the order of 10 mum or larger are removed from the gas due to the centrifugal forces exerted by rotating flow between the shroud and the refractory.