Fuel cell operated mechanical vapor compression MVC desalination system

In Kuwait, the demands for both electric power and desalted water are continuously increasing with water demand outpacing of power demands Co-generation steam power-desalting plants (CPDP) are used to produce both power and desalted water with steam extracted from steam turbines to supply the desalting units (usually multistage flash desalting units). In Kuwait, the power production capacity is matching the peak power demands, but the desalting capacity is below the peak demand. It is not feasible to install more desalters to these CPDP because of the limited number of turbines available to supply extracted steam to the new desalters. Alternative energy source for new desalters, other than steam extracted from turbines, and more energy efficient desalting systems are needed to increase desalting capacity. This paper discusses the feasibility and economics of using a commercially available phosphoric acid fuel cell (PAFC), known as ONSI P25, to operate mechanical vapor compression (MVC) desalting systems for small communities in Kuwait. The PAFC is one of the known fuel cells with documented performance, and is operated by natural gas. The MVC is the most efficient desalting system of distillation. While the PACF electric power output would operate the MVC compressor, the PACF thermal energy is used as auxiliary heat to the MVC system. This drastically reduces the size of the expensive feed pre-heater (usually made of titanium) of the MVC. The technical merits of combining the PAFC with the MVC and the economics involved are outlined