(289am) Analytical Expression for the Non-Isothermal Effectiveness Factor: the Nth-Order Reaction in a Slab Geometry

The problem of calculating the effectiveness factor for a porous slab of catalyst pellet under non-isothermal conditions has been revisited.

For the first time, an exact formal analytical solution was obtained for a nth-order (integer n>=0), exothermic and irreversible chemical reaction (1).

Numerical calculations were performed, and an analytical formula was obtained for the very fast reaction limit. In addition, a fairly simple formula, which was called the low beta approximation, was developped and tested to be valid for low values of the thermicity group beta <=0.1.

This work extends the classical analytical treatment proposed by Aris (2), and provides a useful tool which can be implemented in the simulation and design of heterogeneous reactors, both in porous gas-solid catalysis and immobilized enzime biocatalysis as well.

References:

(1) E. Munoz Tavera, Chemical Engineering Science 60 (2005), 907-916

(2) R. Aris, Chemical Engineering Science 24 (1969), 149-168.