Feasibility study and performance assessment for the integration of a steam-injected gas turbine and thermal desalination system

• Development of thermodynamic, economic, and environmental models for a SIGT–METVC
• Suggestion of performance criteria for retrofitting the SIGT with METVC
• Feasibility study for retrofitting the SIGT plant with a METVC system using RSM
• Multi-objective optimization for minimizing the retrofitted unit product cost

This study proposes a systematic approach for retrofitting a steam-injection gas turbine (SIGT) with a multi-effect thermal vapor compression (METVC) desalination system. The retrofitted unit's product cost of the fresh water (RUPC) was used as a performance criterion, which comprises the thermodynamic, economic, and environmental attributes when calculating the total annual cost of the SIGT–METVC system. For the feasibility study of retrofitting the SIGT plant with the METVC desalination system, the effects of two key parameters were analyzed using response surface methodology (RSM) based on a central composite design (CCD): the steam air ratio (SR) and the temperature difference between the effects of the METVC system (∆TMETVC) on the fresh water production (Qfreshwater) and the net power generation (Wnet) of the SIGT–METVC system. Multi-objective optimization (MOO) which minimizes the modified total annual cost (MTAC) and maximizes the fresh water flow rate was performed to optimize the RUPC of the SIGT–METVC system. The best Pareto optimal solution showed that the SIGT–METVC system with five effects is the best one among the systems with 4–6 effects. This system under optimal operating conditions can save 21.07% and 9.54% of the RUPC, compared to the systems with four and six effects, respectively.