PURPOSE: To efficiently remove NOx in exhaust gas at enough high gas space velocity from an inner combustion engine having a lean air/fuel ratio by using an active alumina having specified pare characteristics as a carrier and depositing tin and silver and/or silver oxide on the carrier.
CONSTITUTION: The relation between the pore radius and pore volume of the active alumina used for the production of a denitration catalyst is measured by a nitrogen gas adsorption method. The active alumina is prepared to have the total pore volume (A) of pores having <300 pore radius, the total pore volume (B) of pores having <50 pore radius, and the total pare volume (C) of pores having 100 to 300 pore radius satisfying (B)≥(A)×30% and (C)≤(A)×15%. By using this catalyst, nitrogen compds. can be reduced and purified at a high space velocity and high conversion rate in an oxygen excess atmosphere where steam is present.
| WO/2012/172944 | EXHAUST GAS AFTER-TREATMENT DEVICE |
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SUGANO TAIJI
WAKABAYASHI MASAO
