Thermal conductivity of porous catalysts

A random pore model of catalytic pore structure is applied to the determination of the thermal conductivity of porous catalytic solids. The low thermal conductivities reported for such materials are explained by considering the microporous particles to consist of a packed bedlike assembly of smaller particles; heat transfer through the solid fraction occurs by conduction through individual small particles in contact with other particles. An expression for the effective thermal conductivity of a gas in the region between ordinary thermal conduction and free molecule conduction is used in determination of heat conduction through the void volume. Agreement of the theory with experimental data on alumina and silver catalysts over a wide range of conditions is good.