Prediction of spatial-temporal evolution of membrane scaling in spiral wound desalination modules by an advanced simulator

There is no method available at present to determine the spatial-temporal evolution of scale throughout the membranes in desalination plants, although it would be most useful for desalination plant design and monitoring. For such tasks, various approaches are followed to estimate the scaling propensity of feed-water or concentrate, including the use of inadequate single-value indices (e.g. LSI, S&DSI). A novel method is presented herein for simulating spatial-temporal scale evolution. It is based on a comprehensive theoretical model, describing transport phenomena in the spacer-filled channel flow of spiral-wound membrane (SWM) modules, and an experimentally determined correlation (akin to a constitutive relation) of two key parameters of the scaling process; i.e. the depositing salt supersaturation ratio at the membrane surface S-w and the rate of scale-mass deposited per unit membrane area, F g/(m(2).h), which represent the driving force and effect of scaling, respectively. Very good agreement is obtained by comparing experimental data from the literature on spatial scale distribution with new computational results. The challenges and priorities are discussed regarding further development of the proposed method as well as applications related to important tasks, such as the design and operation of scale-control and monitoring systems of RO/NF desalination plants.