| 摘要 |
PROBLEM TO BE SOLVED: To purify nitrogen oxides stably over a long period of time by using methane as a reducing agent and to suppress the discharge of methane by using a catalyst for decomposing nitrogen oxides in the presence of methane and a catalyst for oxidizing methane in the case where the combustion waste gas containing excess oxygen is purified. SOLUTION: Nitrogen oxides are decomposed in the presence of a catalyst by using methane as a reducing agent, then methane is decomposed in the presence of another catalyst. At this time, the catalyst for reducing the nitrogen oxides is obtained by depositing palladium and platinum on the carrier of sulfate group zirconia. And, the catalyst for oxidizing methane is obtained by depositing palladium and platinum as a catalyst active component on any carrier of zirconia, sulfate group zirconia and tungsten zirconia. The purifying device of combustion waste gas is constituted by providing each reaction device 1 and 2 provided with each catalyst, and also when the methane amount in the waste gas to be treated at the reaction device 1 is too low, an injection device 3 for previously adding the methane to the waste gas is provided. |
