Pattern formation in fixed bed catalytic reactors—I

Abstract

The possibility of spatial patterns in packed-bed catalytic reactors to improve reactor operation is addressed in this paper with respect to several fundamental issues. The analysis is accomplished with an early model of Liu and Amundson (1962, Ind. Engng Chem. Fundam. 1, 200) which assumes plug flow of the fluid phase and lumped transport resistance in the catalyst particles. Such patterns involve discontinuous concentration profiles in the catalyst phase. It is shown that patterns, which arise due to multiplicity behavior of individual catalyst particles, can be created by providing for an initial pattern in the reactor. Start-up strategies for such initial patterns are established using multiple feeds. Asymptotic stability of patterns in which neighboring particles lie in distinct stable branches is established. Computations demonstrating the achievement of spatial patterns from suitable initial conditions are made. It is shown that reactor operation is concerned with a class of patterns which can provide for an acceptable range of product quality. The significance of patterns lies in improving selective productivities of desired products in multi-reaction systems.