This work discusses the control of a pilot scale (15 cm Dia.) Karr reciprocating extraction column. The system used is Kerosene dispersed in water, in which mass transfer does not occur.
The control scheme developed were tested for servo tracking and regulator control of the holdup of the dispersed phase, the manipulated variance was frequency of the reciprocating plates. Holdup was determined from an empirical correlation using an on-line measurement of column differential pressure.
Dynamic tests indicated the process to be nonlinear and assymmetric in time constant, deadtime and gain. A deadtime was observed between manipulating plate frequency and hold-up of the dispersed phase.
Various controllers were tested; PI ( in feedback or feed forward mode or the combination), Dahlin algorithm. These were compared to the performance of minimum variance controller and S.T.R. All controllers were implemented using a 16 bit microprocessor.
The Dahlin and Minimum variance controllers have been demonstrated to handle process with deadtime better than the PI controller, because they both have deadtime compensator.
It was shown that the S.T.R. is superior over all fixed parameters controllers in handling the non-linearity of the process.