Pilot‐scale investigation and CFD modeling of particle deposition in low‐dust monolithic SCR DeNOx catalysts

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. © 2013 American Institute of Chemical Engineers AIChE J, 59: 1919–1933, 2013

[1]  L. Hegedus,et al.  Design of monolith catalysts for power plant nitrogen oxide (No.+-.) emission control , 1991 .

[2]  P. Saffman The lift on a small sphere in a slow shear flow , 1965, Journal of Fluid Mechanics.

[3]  Goodarz Ahmadi,et al.  Dispersion and Deposition of Spherical Particles from Point Sources in a Turbulent Channel Flow , 1992 .

[4]  Barton E. Dahneke,et al.  Particle Bounce or Capture—Search for an Adequate Theory: I. Conservation-of-Energy Model for a Simple Collision Process , 1995 .

[5]  A. Guha Transport and Deposition of Particles in Turbulent and Laminar Flow , 2008 .

[6]  M. Bohnet,et al.  Calculation of particle–wall adhesion in horizontal gas–solids flow using CFD , 2005 .

[7]  F. Nakajima,et al.  The state-of-the-art technology of NOx control , 1996 .

[8]  O. Levenspiel,et al.  Drag coefficient and terminal velocity of spherical and nonspherical particles , 1989 .

[9]  A. Guha A unified Eulerian theory of turbulent deposition to smooth and rough surfaces , 1997 .

[10]  Jan Erik Johnsson,et al.  Deactivation of V2O5-WO3-TiO2 SCR catalyst at biomass fired power plants: Elucidation of mechanisms by lab- and pilot-scale experiments , 2008 .

[11]  D. Serça,et al.  Global inventory of NOx sources , 2004, Nutrient Cycling in Agroecosystems.

[12]  A. Guha A generalized mass transfer law unifying various particle transport mechanisms in dilute dispersions , 2008 .

[13]  P. Forzatti,et al.  Recent Advances in De‐NOxing Catalysis for Stationary Applications , 1996 .

[14]  John S. Young,et al.  A theory of particle deposition in turbulent pipe flow , 1997, Journal of Fluid Mechanics.

[15]  Michael Lykke Heiredal Particle Dynamics in Monolithic Catalysts , 2010 .