NO x and SO 2 simultaneously during coal combustion may lower the investment and operation cost. The attempts to eliminate such contradictions by coating coal granules with thin layer of monometallic oxides and mixed oxides were proposed. Ni 2 O 3 and Fe 2 O 3 showed high activity on NO x reduction and CaO and Cr 2 O 3 showed good effect on sulfur capture. It is possible to in-bed reduce NO x and SO 2 simultaneously if the adhering materials are properly chosen to be difunctional materials of both active catalysts for NO x reduction reactions and better sorbents for SO 2 retention. The exchange between the phases is represented by source terms in conversation equations.
Turbulence is assumed to be a property of the liquid phase.
A new turbulence modification k - model is introduced to consider the bubbles movement contribution to k and . The dispersion of phases due to turbulence is represented by introducing a diffusion term in mass conservation equation. The mathematical simulation agrees well with the experiment results. The study results indicate that the distance of two nozzles has big effect on fluid flow behavior in the vessel. Using two gas injection nozzles at the half radii of one diameter of the bottom generates a much better mixing than with one nozzle under the condition of the same total gas flow rate.