THE DE-NOX SYSTEM AND THE METHOD FOR EXHAUST GAS AT LOW TEMPERATURE

摘要

PURPOSE: A system for denitrifying exhaust gas at low temperatures and a method for the same are provided to reduce the catalyst amount of a selective catalytic reduction reactor and the size of the reactor and to improve the denitrification efficiency of the reactor. CONSTITUTION: A system for denitrifying exhaust gas at low temperatures is installed at 150 to 200 degrees Celsius region of exhaust gas The system includes a heat exchanger(3), an oxidation reactor(4), and a selective catalytic reduction reactor(5). If exhaust gas at 150 to 200 degrees Celsius is introduced from a heat collecting facility(2) to a denitrification system, the heat exchanger raises the temperature of the exhaust gas to be supplied to an oxidation reactor based on calories of exhaust gas at 300 to 400 degrees Celsius from the oxidation reactor. The oxidation reactor changes the composition ratio of NO and NO_2 in the exhaust gas. A part of nitrogen oxides is denitrified. Exhaust gas from the heat exchanger is re-supplied to the heat exchanger.