Simultaneous removal of NOx and dust with integrated catalytic filter: Interactions between NH3-SCR and filtration processes

Abstract

The integrated selective catalytic reduction of nitrogen oxides by NH3 (NH3-SCR) and dust filtration technology can effectively reduce the energy consumption and space of the flue gas purification system. Herein, a novel catalytic filter is fabricated by in situ depositing FeWOx heterogeneous catalyst onto stainless-steel-fiber filter (named as FeWOx/SSFF), which displays excellent deNOx performance (>85 % NOx conversion and 96 % N2 selectivity) with superior H2O and SO2 tolerance, as well as great dedust efficiency (>99.99 % and low residual pressure drop). The suitable oxygen mobility and enhanced charge transfer ability at the crystalline-amorphous interface contribute well to the excellent SCR performance, and the low pressure drop is promoted by the well dispersion of FeWOx species on the SSFF. Notably, a volcanic relationship between dedust process and SCR performance was obtained, due to the boosting of dedust process for the denitrification, which was confirmed by computational fluid dynamics (CFD). Besides, excessive dust-cake could inhibit SCR performance owing to catalytic site being covered by dust particles. Accordingly, SCR process hardly affected dedust efficiency and residual pressure drop. This work reveals the interactions between SCR and dedust processes, and paves a way to design novel catalytic filters for simultaneously removing dust and gas pollutants at practical conditions.