Transport Phenomena Analysis for Evaluating the Optimum Operating Conditions of Reverse Osmosis Processes

Abstract

In this work, a mathematical model for predicting the performance of reverse osmosis (RO) desalination plants was developed. The proposed model is based on basic transport equations of salt and water across the membrane. The influence of operating variables on the separation efficiency of RO processes can be evaluated by depending on the equations of transport phenomena. The theoretical predication produced by the developed model was compared with the normalized data obtained by Saehan company software CSM2000-program. The comparison indicated that agreement of theoretical values relative to normalized values is about 85%. For specifying the optimum operating conditions, the optimization analysis was carried out by depending on the Modifi cation Hook and Jeeves method. The proposed analysis applied a nonlinear objective function representing the concentration of product water as a function of operating conditions (feed water concentration, operating pressure, and percent recovery).
The optimum concentration of permeate water is governed relative to percent recovery with range about (10-46.67%), the test is repeated for different values of feed water concentration (1000, 3000, and 10000 ppm). The results have shown that, the average of improvement in the optimum values of permeate concentration is about 67%. Also, the optimum concentration of permeate water is inspected for feed water concentration with range (500-10000 ppm), the range of increasing in the optimum permeate concentration is 55.8%. Furthermore, the optimum concentration of permeate water is computed for range of applied pressures in arrange (6.5-25 bar). The results indicated that, when the average operating pressures was increased by 12.7%, the quality of permeate water was improved by 18.8%.