Control of mass transfer and hydrodynamic holdup in a karr solvent extraction column

AbstractThis paper reports an experimental application of multiloop control to a Karr solvent extraction column (a reciprocating plate column). The control objective was to keep the extract outlet concentration above some minimum level and to maintain a high value of dispersed phase holdup while keeping away from the flooding point. Transfer function models were identified from step tests about a nominal operating point and various interaction/operability analysis techniques were used to synthesize a control scheme. The control implemented in this study was a model inversion based scheme in which the extract outlet concentration was controlled by manipulating the continuous phase superficial velocity and the dispersed phase holdup was controlled by manipulating the frequency of reciprocation. Both servomechanism and regulatory responses are presented. A variable dead time Dahlin controller was used to control the extract outlet concentration and a Clarke‐Gawthrop self tuning regulator was used to control the dispersed phase holdup. This multiloop control scheme is compared to single loop control of the extract outlet concentration.

Control of mass transfer and hydrodynamic holdup in a karr solvent extraction column Journal Articles