TARGETED DUCT INJECTION FOR SO3 CONTROL

摘要

NO<SUB>x </SUB>and SO<SUB>3 </SUB>emissions from combustion of a sulfur containing carbonaceous fuel are reduced simultaneously. The combustion gases comprising NO<SUB>x </SUB>and SO<SUB>2 </SUB>are mixed with a NO<SUB>x </SUB>control agent into the combustion gases at a point upstream of a selective catalytic reduction catalyst for reduction of NO<SUB>x</SUB>. Following an SCR catalyst or other equipment that can oxidize SO<SUB>2 </SUB>to SO<SUB>3 </SUB>and prior to contact with an air heater for heating incoming combustion air, magnesium hydroxide is introduced in amounts and with droplet sizes and concentrations effective to form nano-sized particles in the effluent and reduce SO<SUB>3 </SUB>caused by the oxidation of SO<SUB>2 </SUB>in the catalyst. Computational fluid dynamics is employed to determine flow rates and select reagent introduction rates, reagent introduction location(s), reagent concentration, reagent droplet size and/or reagent momentum.