CLEANING TREATMENT OF WASTE GAS CONTAINING NITROGEN OXIDE COMPOUND

摘要

PURPOSE:To efficiently remove NOx in a waste gas containing SOx without lowering the activity of a catalyst to be used in an oxidative atmosphere in which excessive oxygen exists and remove incomplete combustion products sometimes discharged by the removal of the NOx. CONSTITUTION:In the presence of hydrocarbons or oxygen-containing compounds (hydrocarbons hereafter) existing in a waste gas or introduced from outside, a waste gas is brought into contact with a catalyst containing transition metal ion-exchanged clays (montmorillonite group, micaceous clay mineral group, kaolinite mineral group, etc.). The catalyst preferentially accelerates the reaction of NOx with hydrocarbons rather than the reaction of oxygen with the hydrocarbons in an oxidative atmosphere and thus NOx in the waste gas is removed highly efficiently. Also, the waste gas after being brought into contact with the catalyst is brought into contact with an oxidation catalyst to remove incomplete combustion products.