Catalytic combusition of hydrogen on platinum wires.

The aim of this study is to make clear the mechanism of catalytic combustion on platinum wires. As a theoretical study, assuming heat and mass transfer analogy and taking into account the heat conduction along the wire, wire temperature is predicted. In the experimental study, platinum wires were set horizontally in a square tube. After the ignition of catalytic combustion, the temperatures of the wires were measured in a mixed gas composed of hydrogen, air and carbon dioxide. From these Studies, it was made clear that: (1)If the excess air ratio is less than 2.4, the wire temperature increases rapidly and linearly with the excess air ratio, and the gradient becomes small when the excess air ratio exceeds 2.4. (2)Theoretical analysis, assuming heat and mass transfer analogy and taking into account the heat conduction, predicts the above-mentioned features correctly. (3)In cases of large diameter or rich hydrogen, the influence of heat conduction cannot be neglected.