| 摘要 |
PROBLEM TO BE SOLVED: To provide a practical, highly active decomposition catalyst capable of removing NOx , especially, NO contained in exhaust gases originated from all combus tion apparatus, regardless of fixed generation sources or moving generation sources or derived from fuels or combustion air by directly decomposing them at high temp. without reducing agents, and to provide the practical method for NOx removal using the catalyst for treating the exhaust gas containing oxygen and steam. SOLUTION: The decomposition catalyst containing, as a catalytically active component, at least one metal complex oxide of the composition formula AM1-x Ex O3+-z (A is an alkaline earth metal; M is an element of the iron group elements; E is a metal selected from vanadium group metals; 0<x<1; z is oxygen defect number or oxygen excess number of metal oxide at the room temp. and ambient pressure), preferably, whose crystalline structure is a perovskite-type, is used for removing nitrogen oxides. As this catalyst has a high resistance against the poisoning caused by steam, the nitrogen oxides in the exhaust gas containing steam can be removed by directly bringing the exhaust gas into contact with the catalyst at 600-1,000 deg.C, in the presence of or in the absence of oxygen without removing moisture from and drying the gas and without adding reducing agents. |
