Catalytic activation of ceramic filter elements for combined particle separation, NOx removal and VOC total oxidation

The development of a catalytically active filter element for combined particle separation and NOx removal or VOC total oxidation, respectively, is presented. For NOx removal by selective catalytic reduction (SCR) a catalytic coating based on a TiO2-V2O5-WO3 catalyst system was developed on a ceramic filter element. Different TiO2 sols of tailor-made mean particle size between 40 and 190 nm were prepared by the sol-gel process and used for the impregnation of filter element cylinders by the incipient wetness technique. The obtained TiO2-impregnated sintered filter element cylinders exhibit BET surface areas in the range between 0.5 and 1.3 m(2)/g. Selected TiO2-impregnated filter element cylinders of high BET surface area were catalytically activated by impregnation with a V2O5 and WO3 precursor solution. The obtained catalytic filter element cylinders show high SCR activity leading to 96% NO conversion at 300 degrees C, a filtration velocity of 2 cm/s and an NO inlet concentration of 500 vol.- ppm. The corresponding differential pressures fulfill the requirements for typical hot gas filtration applications. For VOC total oxidation, a TiO2-impregnated filter element support was catalytically activated with a Pt/V2O5 system. Complete oxidation of propene with 100% selectivity to CO2 was achieved at 300 degrees C, a filtration velocity of 2 cm/s and a propene inlet concentration of 300 vol.-ppm. (c) 2006 Elsevier B.V. All rights reserved.