Techno-economic analysis of combined gas turbine, MED and RO desalination systems to produce electricity and drinkable water

Abstract

Water and power cogeneration systems have been received more attention in recent years. In the present research, in addition to techno-economic investigation of the integration of multiple effect desalination/thermal vapor compression (MED/TVC) system and reverse osmosis (RO) system into the gas turbine (GT) power cycle, the GT/MED-TVC/RO configuration is also proposed. At first, the models used for GT, MED-TVC and RO systems are validated with the experimental data in the literature and good correspondence is found. In this study, the effect of air temperature on the GT stack outlet gases and the effect of seawater temperature on the MED-TVC GOR are investigated. Moreover, using the RO energy analysis, the most suitable RO membrane is selected by considering the permeate quality and membrane price. Then, the LCOE and LCOW for three scenarios of GT/ MED-TVC with 5000 m 3 /d, GT/RO with 5000 m 3 /d, and GT/MED-TVC/RO with MED-TVC and RO water production rates of 2000 m 3 /d and 3000 m 3 /d, respectively are determined. The results of the economic analysis in three scenarios showed that the least electricity cost and the least freshwater production cost belong to GT/MED-TVC and GT/RO configurations, respectively. Furthermore, the effect of number of stages of the MED-TVC system on the energy and economy of the GT/MED-TVC/ RO configuration is explored. It was observed that increasing the number of effects from 4 to 7 has no tangible effect on the LCOE. In addition, the output temperature and concentration of GT/MED-TVC/RO plant at different number of MED-TVC effects is determined. Finally, the effect of fuel cost and desalination system scale on the LCOW and LCOE at three configurations are investigated.