Thermoeconomic analysis of combined power cycle integrated with MSF/SWRO desalination plant

A comprehensive thermo-economic study based on the exergy accounting method is conducted to evaluate the performance of a combined gas/steam power generation system integrated with a hybrid multistage flash (MSF)/sea water reverse osmosis (SWRO) desalination plants. The plant consists of five combined power generation cycles. Each cycle incorporates, two gas turbines (GT), two heat recovery steam generators, and one steam turbine. The total power generated is 2,645.5 MW. The combined power generation cycles are integrated with a hybrid MSF/SWRO desalination plant with a total water production of 1,000,000 m3/d, of which 70% is produced by MSF and 30% by SWRO. The exergy accounting study revealed that the heat rate of the combined gas/steam power cycle is 6,388.94 kJ/kWh, corresponding to an overall thermal efficiency of 56.34%. On the other hand, the water specific fuel energy consumption of the hybrid SWRO/MSF plant is 33.74 kWh/m3. The suggested exergy cost accounting method shows the water unit production cost varying from $0.8258/m3 to $2.259/m3 and the per unit electricity generation cost varying from $0.02266/kWh to $0.0966/kWh, as the oil price is increased from $6/bbl to $72/bbl, respectively.