| 摘要 |
PURPOSE:To enable an effective use of an expensive noble metal catalyst through the elongation of durability of the same by providing a combustion apparatus storing a catalyst having palladium as a main active component at the first-half stage side and storing a catalyst having platinum-rhodium alloy as a main active component at the second-half stage side with fuel, performing ignition of fuel mainly at the first-half stage side and combution of fuel at the second-half stage side. CONSTITUTION:A palladium catalyst is packed in the first-half stage side while a platinum-rhodium alloy catalyst in the second-half stage side, and natural gases containing methane are burned in contact with the air under normal pressure. Then, ignition of fuel is performed by palladium at the first half stage side, and the combustion of fuel ignited by the platinum-rhodium alloy is continued at high temperature at the second-half stage side because of high ignitability of palladium. In this method, although platinum which is apt to be converted into an oxide is contained as a catalytic component, it is free of sublimation due to oxidation because it exists in the form of an alloy with rhodium, so that prolanged use of a highly activated catalyst is realized.
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