REMOVAL OF NITROGEN OXIDE

PURPOSE:To remove nitrogen oxides with a good degree of efficiency by providing a decomposition tank fitted with a partition having pores in a specific temperature zone of a used gas exhausting passageway, feeding isocyanuric acid thereto and bringing the exhaust gas into contact with the isocyanuric acid through the pores of the partition. CONSTITUTION:A decomposition tank 5 fitted with a partition having pores 4 is provided in the temperature zone of 330-700 deg.C of a used gas exhausting passageway. Isocyanuric acid is fed in a constant amount from the bottom of a hopper 6 to the decomposition tank 5 by a screw type constant feed weigher 7. The exhaust gas is then brought into contact with the isocyanuric acid or the gas liberated therefrom through the pores 4 of the partition and the exhaust gas containing the isocyanuric acid gas emitted from the decomposition tank 5 is introduced into a flue 2, thereby permitting an efficient removal of nitrogen oxides from the exhaust gas.