CFD modeling of unsteady SCR deNOx coupled with regenerative heat transfer in honeycomb regenerators partly coated by Vanadium catalysts

Abstract

The unsteady selective catalytic reduction (SCR) of NOx with honeycomb regenerators coated by Vanadium catalysts, under the condition of hot gas and cool air blowing alternately in the opposite direction, should be simulated coupled with regenerative heat transfer, because catalyst activity depends on temperature greatly. In the current work, the SCR deNOx model based on the porous medium and volumetric reaction assumptions is developed for the catalyst layer and integrated into our existing three-dimensional (3D) CFD heat transfer model of honeycomb regenerators. Steady SCR deNOx experiments with monolith catalysts are simulated for model validation and the contour is presented to study the NOx concentration polarization. With the novel model, unsteady SCR deNOx in honeycomb regenerators partly coated by a film of V2O5-WO3/TiO2 is simulated, and the effects of structural and operational parameters on the NOx conversion and thermal-hydraulic performances are studied. Besides, the temporal variation curves of fluid temperatures and NO concentration are presented for discussions. Numerical results demonstrate that current CFD model could predict the performances of partly-coated honeycomb regenerators with a reasonable precision and the regenerator with square openings of 6mm×6mm could work with a good overall performance at the gas inlet velocity of 4m/s.