Modeling of chemical reactors — XXII Effect of simultaneous heat and mass transfer inside and outside of a pellet on reaction rate — II

Abstract

In this paper a simple approximation is described making it possible to evaluate the dependence between effectiveness factor η and Thiele parameter φ for simultaneous heat and mass transfer outside and within a porous catalytic particle. The suggested model includes heat and mass transfer in an external film and mass transfer inside of a porous structure. The whole procedure is described in detail for first order reaction, where the solution can be obtained on the basis of tabulated functions. For the general kinetics a numerical integration of the mass balance is necessary. For an approximate model an analysis of multiplicity is performed in detail. The accuracy of the approximation is discussed and, furthermore, it is shown that for exothermic reactions this procedure can always be used for an evaluation of effectiveness factor.