SYSTEM AND METHOD FOR THE SELECTIVE CATALYTIC REDUCTION OF NITROGEN OXIDE IN A GAS STREAM

摘要

A system and method for the selective catalytic reduction of nitrogen oxide in a furnace exhaust includes cooling the furnace exhaust in a first heat recovery (13') section to a temperature between 400~ F and 500~ F, introduci ng a reducing agent into the exhaust gas and reacting the nitrogen oxide in the exhaust gas with the reducing agent in the presence of an SCR catalyst (19) in a reactor (10) positioned in the furnace stack. The treated gas emerging fro m the reactor can be further cooled in a second heat recovery section (15). Th e system and process is particularly suitable for use in conjunction with furnaces for thermally cracking hydrocarbon feedstock to produce olefin. The feedstock is preferably preheated in the heat recovery sections prior to introduction into the furnace.