Co-generation power desalting plants: new outlook with gas turbines

Kuwait is using only MSF desalting system coupled to steam turbines to desalt seawater. There is shortage in desalting capacity, and 180 MIGD desalting units have to be installed within 5 years. Meanwhile there are not enough operating steam turbines to supply steam to desalting units if MSF units are chosen. At the same time there are peak load gas turbines (GT) that are usually operated for very short times, only 16 h in the year 2001 as example. Also Kuwait is planning to have 400-MW total capacity GT just to be operated at peak load. These GT can be used to operate reverse osmosis (RO) desalting system, when not needed to carry load. Other desalting types can be added, beside the RO system, to produce water more efficiently, energy wise than the presently used method. Forming combined gas/steam cycles by adding steam turbines to these GT increases the installed power capacity, efficiency of power production, and ability to produce more water. This paper presents some variants of combining GT with desalting systems. These variants use standard, well-proven type and reliable equipment, besides being more energy efficient compared to MSF units combined with steam turbines.