Comparative thermodynamic performance study for the design of power and desalting cogeneration technologies in Kuwait

Abstract

This study attempts to answer two questions by developing a thermodynamic mathematical model: which is the optimal energy conversion process, generating power and desalting water independently or coupling power generation with seawater desalination technologies via cogeneration power and desalting plants (CPDP)? How would modifying the plant design affect the performance of a CPDP? Nine different configurations of power and water conversion technologies are modeled and compared with respect to an ideal reversible CPDP using a newly introduced cost-based dimensionless parameter, the power and water gain ratio (PWGR). Results of this study show that producing power using a gas turbine combined cycle (GTCC) and desalting seawater using reverse osmosis (RO) on a stand-alone basis is the most energy efficient for generating power and desalinating water simultaneously. GTCC-RO has the closest PWGR set at 1.470 to the ideal reversible reference plant’s 1.529 PWGR. Modifying the number of gas turbines (GT), steam turbines (ST), and multi-effect distillation (MED) units can improve the performance of the combined cycle heat and power (CCHP) reference plant coupled with MED desalination units.