On-line startup of a distillation column using generic model control

Abstract A new on-line control algorithm, based on Generic Model Control, is proposed for improving the automatic startup of a binary distillation column. The nonlinear controller “looks” at the process at every controller time interval and calculates the set point value of the reflux flow PI loop that tracks the composition profile to the desired steady state. Temperatures on five trays, condenser heat duty, distillate and reflux flow rate, level of the overhead accumulator, reflux temperature and pressure drop in the column are used as inputs to the estimator. A series of tests has been performed on an industrial-scale distillation column. The experimental results demonstrate the effectiveness and robustness of the proposed method with respect to process/model mismatch. The implementation of the algorithm is simple and can be accomplished with standard industrial instrumentation and a cheap personal computer.