A spatiotemporal model for dynamic RO simulations

Abstract A spatiotemporal model is developed for dynamic simulations of RO desalination. The model explicitly accounts for pressure drop, concentration polarization and axial dispersion along the pressure vessels. A detailed numerical method, which is based on orthogonal collocation on finite elements in the spatial domain, is presented to solve the coupled partial differential equations (PDEs) in the model. Two examples, RO with periodic feed flow reversal and membrane flushing with/without permeation flux in batch operations, are used to demonstrate the applications of the proposed model. The simulation indicates that salt concentration overshoots during feed flow reversal. For batch operations, flushing efficacy is significantly improved if permeate flux is turned off during the flushing period.