Control of a reverse osmosis desalination process at high recovery

Feed-forward/feedback control techniques that utilize Lyapunov-based control laws are implemented on a high recovery reverse osmosis desalination plant model. A detailed mathematical model of a high recovery reverse osmosis plant is developed. This model incorporates the large spatial variations of concentration and flow-rate that occur in membrane units during high recovery operation. Bounded nonlinear feedback and feed-forward controllers are developed and applied to this system. The application of these controllers is demonstrated in the context of a high recovery reverse osmosis process simulation. The scenarios demonstrate the ability to compensate for the effects of large time varying disturbances in the feed concentration on specific process outputs with feedforward/feedback control.