Implementing multiple-effect distillation and reverse osmosis thermal coupling to improve desalination process performance in combined water and power plants

[Display omitted] •Coupling between multiple-effect distillation and reverse osmosis was considered.•A novel dual purpose condenser via reverse osmosis reject was proposed.•To demonstrate the influence of coupling techno-economic evaluation was conducted. Cogeneration has recently been an appropriate engineering approach to supply increasing energy demands. The present study demonstrates a significant influence on increase in productivity and reduction of utility consumption of thermal desalination, considering a novel internally coupled multiple-effect distillation and reverse osmosis desalination process in a cogeneration of water and power plant. The proposed power generation unit, consisting of two SGT600 gas turbines as prime movers, two heat recovery steam generators and one back-pressure steam turbine, has been applied. The objective is to propose a modified multiple-effect distillation process, due to availability of sufficient cooling water, provided by reverse osmosis reject water. The basic configuration comprises a hybrid desalination using a dual purpose condenser, results of which showed a 45% reduction in electrical energy consumption of multiple-effect distillation, accompanying a 67% decrease in intake water cost. In modified configuration, condenser temperature decreases from 48 to 45℃, allowing number of effects to increase from 5 to 7. Therefore, produced water rate and gain output ratio of the modified multiple-effect distillation increase by 30% and 31%, respectively, while specific energy consumption decreases by 6%, causing a two-year reduction in cogeneration of water and power plant pay-back period compared to the basic configuration.