Selective catalytic reduction of NOx by hydrocarbons/oxygenates. Application for the control of NOx from the regenerator of a fluid catalytic cracking pilot-plant unit

Rh supported on gamma -alumina and unpromoted y-alumina were used as cataly sts for the selective catalytic reduction of NO by propene and methanol, re spectively. Fixed-bed experiments were initially performed to study the cat alytic activity using a feed that simulates flue gases. Emphasis was placed on the SO2 effect on the NO reduction activity. A fluidized-bed deNO(x) un it was connected to the exit of the regenerator of a pilot-plant-scale flui d catalytic cracking unit aiming at the cleanup of this stream from gaseous pollutants. The deNO(x) catalysts and the reductants were the same as thos e in the fixed-bed experiments. More than 70% of the incoming NO was conver ted to N-2 when the deNO(x) unit was operated at the appropriate temperatur e range. Moreover, up to 90% of the inlet CO was oxidized to CO2 at suffici ently high temperatures. At the same temperatures SO2 was adsorbed by alumi na.