PATTERN-FORMATION IN FIXED-BED CATALYTIC REACTORS .1.

The possibility of spatial patterns in packed-bed catalytic reactors t o improve reactor operation is addressed in this paper with respect to several fundamental issues. The analysis is accomplished with an earl y model of Liu and Amundson (1962, Ind. Engng Chem. Fundam. 1, 200) wh ich assumes plug how of the fluid phase and lumped transport resistanc e in the catalyst particles. Such patterns involve discontinuous conce ntration profiles in the catalyst phase. It is shown that patterns, wh ich arise due to multiplicity behavior of individual catalyst particle s, can be created by providing for an initial pattern in the reactor. Start-up strategies for such initial patterns are established using mu ltiple feeds. Asymptotic stability of patterns in which neighboring pa rticles lie in distinct stable branches is established. Computations d emonstrating 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 select ive productivities of desired products in multi-reaction systems. Copy right (C) 1996 Elsevier Science Ltd