Partial oxidation of propane using micro structured reactors

Various catalysts based on rhodium, palladium and platinum on γ-alumina were wash-coated into micro structured reactors. The catalysts were applied in the partial oxidation of propane aiming for synthesis gas. Best results were achieved with pure rhodium and bimetallic rhodium/platinum catalysts having at least a rhodium concentration exceeding 0.5 wt.%. With rhodium-based catalysts complete propane conversion was observed. Selectivities of hydrogen and carbon monoxide were close to the thermodynamic equilibrium. During long-term operation, coke formation was observed resulting in an increase of the pressure drop over the reactors. Upon inspection of the reactors it turned out that the micro channels were marginally covered with coke depositions but the outlet tube of the reactor was found to be fully plugged. With the help of a simulated reformate it was found that coke formation was only little dependent on the operating temperature. In contrast, coke formation was significantly reduced by the employment of reaction plates made of a nickel-free stainless steel and by a protective coating consisting of α-alumina.