Deposition of particles in selective catalytic reduction DeNOx monolithic catalysts was studied by low-dust pilot-scale experiments. The experiments showed a total deposition efficiency of about 30%, and the deposition pattern was similar to that observed in full-scale low-dust applications. On extended exposure to the dust-laden flue gas, complete blocking of channels was observed, showing that also in low-dust applications soot blowing is necessary to keep the catalyst clean. A particle deposition model was developed in computational fluid dynamics, and simulations were carried out assuming either laminar or turbulent flow. Assuming laminar flow, the accumulated mass was underpredicted with a factor of about 17, whereas assuming turbulent flow overpredicted the experimental result with a factor of about 2. The simulations showed that turbulent diffusion in the monolith channels and inertial impaction and gravitational settling on the top of the monolith were the dominating mechanisms for particle deposition on the catalyst. (c) 2013 American Institute of Chemical Engineers AIChE J, 59: 19191933, 2013