Optimization-based periodic forcing of RO desalination process for improved performance

AbstractThe performance of a tubular reverse osmosis (RO) process for water desalination is investigated using periodically forced feed parameters. The study was performed using a dynamic model that was developed and validated in a previous work. Simultaneous forcing of feed pressure and flow rate were studied. Fully symmetric rectangular pulses were used for input forcing because of their applicability for digital control implementation. It was found that the simultaneous periodic operation of the RO inputs improves its performance in the sense of higher permeate flow rate and reduced salt concentration. Increasing the pressure forcing amplitude will further enhance the performance; however, the attainable performance is limited by the constraints on the operating pressure. Depending on the RO unit constraints and characteristics, a maximum increase in permeate flow rate up to 42% and reduction in salt concentration of about 20% could be obtained.