Understanding performance improvement of forced periodic operation of stirred tank reactors

Abstract It is well-known that the performance of chemical reaction processes can be improved by periodic forcing. The π-criterion has been introduced and applied extensively to quantitatively assess the potential of periodic forcing in a particular case, though it is difficult to understand the physical reasons for the performance improvement. A theoretical analysis in the frequency domain and a study of typical model reaction systems in stirred tanks including parallel, consecutive and reversible reactions is presented here. It is shown that the performance improvement can clearly be related to resonance phenomena displayed by the linearized dynamics in conjunction with a nonlinear variation of the process gain in the region of forcing. The theoretical findings are illustrated by a number of examples.