| 摘要 |
PURPOSE:To sufficiently denitrificate exhaust gas even if the concn. change of nitrogen oxide in the exhaust gas is remarkable, by preliminarily adsorbing ammonia with a vanadium oxide-containing catalyst layer held at a predetermined temp. while passing the exhaust gas in which a proper amount of ammonia is mixed through the ammonia adsorbed catalyst layer. CONSTITUTION:Gas containing nitrogen oxide is passed through a vanadium oxide-containing catalyst layer which is held at a temp. of 180-270 deg.C and has ammonia preliminarily adsorbed therewith while mixing ammonia in said gas in an amount of 0.8-1.2 times on the basis of a stoichiometric amount reguired in reducing said nitrogen oxide to perform the sufficient removal of nitrogen oxide in the above mentioned exhaust gas even if the concn. of the nitrogen oxide in said exhaust gas is pulsated in a unit of a several ten sec-several min and the difference between the max. value and the min. value in the concn. thereof is remarkably changed in a ratio of 10% or more. In addition, in the above mentioned method, it is necessary to bring the amount of ammonia allowed to be preliminarily adsorbed with the catalyst layer to 1.0 times or more on the basis of a stoichiometric amount required in reducing the integration amount of nitrogen oxide corresponding to one pulsation portion in the concn. of nitrogen oxide. |
