Effect of gas composition on the selective reduction of NOx with ammonia over Vanadia based catalysts

Abstract

The catalytic reduction of NO_x under different oxygen concentrations leading to different NO/NO₂ compositions has been studied in the presence of V3W9Ti and V8W9Ti catalysts in a tubular flow reactor. The results have shown that increasing O₂ concentration leads to increase the NO_x reduction in low temperature range [150-275 °C]. Slight effect of O₂ concentration on NO_x conversion was observed at higher temperatures. SCR reaction also occurred in the absence of gaseous oxygen but with low NO conversion indicating the strong redox properties of both catalysts. Aged catalysts exhibited relative good activities in NO_x reduction. This is probably due to the sol gel method used for the preparation of the catalysts known to improve the catalysts properties.

Keywords

• SCR; Oxygen concentration; NO-NO2 mixture; Ammonia oxidation; TPD; Aging.

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