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.

开发了用于反渗透海水淡化动态模拟的时空模型。该模型明确考虑了沿压力容器的压降、浓差极化和轴向色散。提出了一种基于空间域有限元正交配置的详细数值方法来求解模型中的耦合偏微分方程(PDE)。两个例子，具有周期性进料流反转的 RO 和在批处理操作中有/没有渗透通量的膜冲洗，用于演示所提出模型的应用。模拟表明在进料流反转期间盐浓度超调。对于批量操作，如果在冲洗期间关闭渗透通量，冲洗效率会显着提高。