Heat conduction heal capacity

Note that the thermal conductivity k represents how well a material conducts heat, and the heat capacity pCp represents how much energy a material stores per unit volume. Therefore, the themial diffusivity of a material can be viewed as the ratio of the heat conducted through the material to the heat stored per unit volume, A material that has a high thermal conductivity or a low heal capacity will obviously have a large thermal diffusivity. The larger the thermal diffusivity, the faster the propagation of heal into the medium, A small value of thennal diffusivity means that heal is mo.stly absorbed by the material ahd a small amount of heat is conducted further. 

Since there is no radial bulk transport of fluid between the monolith channels, each channel acts basically as a separate reactor. This may be a disadvantage for exothermic reactions. The radial heat transfer occurs only by conduction through the solid walls. Ceramic monoliths are operated at nearly adiabatic conditions due to their low thermal conductivities. However, in gas-liquid reactions, due to the high heat capacity of the liquid, an external heat exchanger will be sufficient to control the reactor temperature. Also, metallic monoliths with high heal conduction in the solid material can exhibit higher radial heat transfer. 

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