MICROCATALYTIC COMBUSTION OF H_2 ON PT/AL_2O_3-COATED NICKEL FOAM

摘要

A new catalyst support, nickel foam, was suggested for use in a microcatalytic combustor. A1_2O_3 was coated on nickel foam to increase the surface area using a coating slurry prepared by a modified sol-gel process. Rough surface was observed in the SEM examination of Al_2O_3-coated nickel foam, H_2 catalytic combustion was carried out using PtlAl_2O_3-coated nickel foam to confirm the reactivity as a catalyst for combustion with different flow rates and equivalence ratios. The height of combustion chamber was 1 mm. Combustion was successful, and conversion rates were over 99%. When the equivalence ratio was 0.1, even though the H_2 concentration was the lower flammability limit of the homogeneous gas phase combustion of H_2 and air mixture, the conversion rates was more than 92%. Temperature and conversion rates increased more rapidly at the beginning of reaction, when equivalence ratio was low for fixed H_2 flow rates. These were explained by the influence of water condensed in the combustor at low temperature.