(503c) Intensification of Chemical Processes Via Periodic Operation

Authors: 
Yan, L., McKetta Department of Chemical Engineering, The University of Texas at Austin
Baldea, M., The University of Texas at Austin
Edgar, T. F., McKetta Department of Chemical Engineering, The University of Texas at Austin
Process intensification has emerged over the past few decades as a framework for increasing process
performance by bringing chemical and physical phenomena into closer physical proximity.
Intensification often transcends the traditional unit operations framework, with several conventional
operations occurring in the same physical device. While this minimizes transport limitations and reduces
equipment size, it can also lead to control challenges: intensified processes feature strong dynamic
coupling between phenomena and have fewer control degrees of freedom than their conventional
counterparts1.

In this presentation, we describe a new means of operating intensified processes, focusing on
deliberately imposing a transient (specifically, periodic) operating regime in order to improve average
process performance. Additionally, we discuss periodic operation in terms of expanding the number of
control degrees of freedom, in the sense that the amplitude and period of oscillation of a single
manipulated variable can be set independently.

Using a prototype process featuring several coupled (and possibly competing) phenomena, we
demonstrate theoretically that periodic operation can increase overall economic performance. We
perform simulations to illustrate our theoretical findings, using both the canonical example described
above, and the model of a dividing-wall column.

References
[1] Schembecker, G.; Tlatlik, S. Process Synthesis For Reactive Separations. Chem. Eng. Process. 2003, 42, 179-189.