METHOD AND APPARATUS FOR REDUCING NITROGEN OXIDES IN COMBUSTION EXHAUST GAS

摘要

PURPOSE:To decompose concurrently residual NOx and NH3 in the denitrification process by injecting NH3 into the high temperature range of combuster by the procedure in which exhaust gas after combustion is passed through a catalyst layer with catalyst arranged in parallel with the flow direction of gas in a specific temperature range. CONSTITUTION:NH3 from the nozzle 2 arranged in the region in which the temperature of exhaust gas containing NOx generated from the main burner 1 is 700 to 1300 deg.C is injected into the exhaust gas to decompose NOx in the presence of O2. Then, the exhaust gas after combustion which is in the temperature range of 300 to 500 deg.C is introduced into the catalyst layer 6 consisting of the plate catalyst 11 arranged in parallel with the flow direction 12 of exhaust gas to concurrently decompose residual NOx and NH3. In this case, NH3 equivalent to 0.5 to 1.5 times (in molar ratio) than amount of NOx present in exhaust gas is injected.