Cost analysis of multiple effect evaporation and membrane distillation hybrid desalination system

This work addresses the feasibility of a previously proposed hybrid desalination system comprising multiple effect evaporation (MEE) and membrane distillation (MD) processes. The feasibility study introduced here focuses on the impact of the hybridization of two separate processes on desalination plant economics. The water cost of the hybrid system is found to be 2.05 $/m3, which compares well with previously reported values and is 17% lower than that of standalone MEE system. The sensitivity of the water production cost to the MD feed flow rate indicated the existence of an optimal cost at a single-pass feed flow rate of 900 L/h. In addition, the sensitivity of the water cost with respect to the MD unit cost indicated a 0.0084 $/m3 change in water production cost for every unit change in the MD module cost. A modified structure of the hybrid system that leverages the thermal energy of all MEE effluents has also been suggested. With this system, the overall water recovery ratio can reach as high as 52% and the water cost can further be reduced to 1.84 $/m3.