Assessing the Accuracy of Wall Concentration Estimation Based on Averaged Permeate Velocity in Spacer-Filled Reverse Osmosis (RO) Membrane Systems

Abstract

The accuracy of estimations of wall concentration using the constant (averaged) permeate velocity method was assessed in both empty and spacer-filled reverse osmosis (RO) channels under various operation conditions, based on the simulation results of a two-dimensional (2-D) concentration polarization model. It was determined that, although it always results in substantially larger variations of wall concentrations, the constant permeate velocity method is able to mimic the general variation patterns of wall concentrations in both empty and spacer-filled channels. The constant permeate velocity method can reasonably estimate the averaged wall concentration. The error is usually <10%, under the simulation conditions. It was also determined that the constant permeate velocity method always overestimates the maximum wall concentration. For the membrane that is not in contact with transverse filaments, the error is usually within 20%, and increasing the mesh length or increasing the system value of Δp/Δπ0 woul...