DYNAMICS AND CONTROL OF RECYCLE SYSTEMS .1. SIMPLE OPEN-LOOP AND CLOSED-LOOP SYSTEMS

This paper is the first part of a series of papers that explore the challenging problems associated with the dynamics and control of recycle systems. The purpose of this paper is to set the stage for the subsequent parts. The problem will be defined and the literature surveyed. Then some of the interesting phenomena, most of which have been discussed by previous workers, will be illustrated by the use of some very simple systems. First transfer function models will be used to show the effects of various parameters (steady-state gains and time constants) of the individual units in a recycle process and the over all dynamics of the total process. Then a simple reactor/column process will be considered. No claim is made that the material in this paper provides a significant advance to the field of recycle control. Its purpose is to illustrate some well-known and some not-so-well-known phenomena that occur in recycle systems. Generic guidelines and a general design methodology will be developed in future parts.