Optimal plant operation of brackish water reverse osmosis (BWRO) desalination

Optimal plant operation of brackish water reverse osmosis (BWRO) desalination is studied in this work to reduce specific energy consumption (SEC). A comprehensive first-principles based mathematical model, which explicitly accounts for membrane area and hydraulic permeability, pump characteristic curves, and pressure drops along the RO train, is developed and validated by plant data. A constrained nonlinear optimization is formulated and solved for two RO trains with different service times. It is shown that a 16% reduction in SEC is possible by optimizing operating conditions within the normal operating range of the pump while maintaining the same permeate rate. Results are discussed using dimensionless parameters derived in the author's previous work. Suggestions are made to further reduce SEC in BWRO plant operation.

► Model-based optimization was developed to guide RO operation.
► Model accounted for pump characteristic map and pressure drop along RO train.
► Modeling results were validated by plant data.
► Optimization results were explained using dimensionless parameters.
► Effect of permeability degradation on RO operation was discussed.