METHOD FOR PURIFYING NITROGEN OXIDES-CONTAINING GAS AND DEVICE THEREFOR

摘要

PURPOSE:To obtain a method high in activity at low temp. region in a purifying method of a nitrogen oxides-containing gas in which nitrogen oxides are reduced by a selective reducing method to make them harmless. CONSTITUTION:An SV value (h<-1>) being a ratio of an amount of the nitrogen oxides-containing gas introduced to a nitrogen oxides treating part and the amount of an alumina based nitrogen oxides reducing catalyst disposed at the nitrogen oxide treating part is set in a prescribed value, and a linear velocity of the nitrogen oxides-containing gas being the velocity along a flowing out direction from a flowing in direction at the nitrogen oxide treating part is set less than 10cm/s to improve an activity of the nitrogen oxides reducing catalyst at low temp. region.