DENITRIFICATION CATALYST AND DENITRIFYING METHOD USING THE SAME

摘要

PURPOSE:To obtain a denitrification catalyst so that NOx in exhaust gas from an inner combustion engine with a lean air-fuel ratio can be efficiently removed with sufficiently high gas velocity and to provide a denitrification method with a high efficiency and high reliability for NOx in exhaust gas in an inner combustion engine with a lean air-fuel ratio by using the catalyst. CONSTITUTION:Such an active alumina is used as a carrier that the volume of pores having <=50Angstrom pore radius measured by nitrogen gas adsorption method, and the volume of pares having 100-300Angstrom radius are respectively >=50% and <=10% of the volume of pores having 0-300Angstrom radius. Titanium-silver, or titanium-silver oxide, tin or indium are deposited on this carrier to obtain a denitrification catalyst. When exhaust gas from an inner combustion engine driven with a lean air-fuel ratio is denitrified by passing the gas through a denitrification catalyst layer, the denitrification catalyst above described is used for the denitrification catalyst layer. The exhaust gas passing through the denitrification catalyst layer is kept in 400-600 deg.C temp. range at the entrance of the denitrification catalyst.