Dynamics and control of membrane-based electrochemical processes

摘要

Electrochemical reactors based on ionomeric membranes are the subject of much current industrial activity in a wide variety of applications, including fuel cells, salt splitting, electroorganic syntheses, metal recovery systems, ozone and hydrogen peroxide generation, and acid catalysis. These reactors are extremely interesting from a control perspective because they represent reaction/separation systems in which these tow basic unit operations are intimately coupled, as in reactive distillation. In addition, there is evidence to suggest that gas-fed membrane electrolysis cells can exhibit open-loop instability at high current densities. Since process economics generally argue in favor of maximizing operating current densities (which determine production rate per unit cell area), there is a strong practical motivation for the development of stabilizing feedback controllers. As a first step toward this objective, this paper describes a first-principles model of the dynamics of a simple ionomeric membrane reactor system and some preliminary results concerning its qualitative behavior, particularly in the regime of high operating current densities.