EVOLUTIONARY DEVELOPMENTS OF THERMAL DESALINATION PLANTS IN THE ARAB GULF REGION1

The majority of large scale desalination plants in the Arab Gulf Region (AGR) employ thermal desalination processes. Around 2345 MIGD of desalinated water that accounts for 77 % of the total water production in the AGR, was produced by thermal desalination processes in 2002. Due to its simplicity, reliability and huge capacity, the multistage flash (MSF) distillation process was the most dominant and frequently used process. It produced 94 % of the total production of thermal desalination processes in the Gulf region. The multi-effect distillation (MED) coupled with thermal vapor compression (TVC) accounted for 6%. The basic evolutionary developments which were introduced in the MSF process during the last four decades such as successful scale and corrosion control techniques and increase of distiller production capacity will be reviewed. The outstanding design and operating features of MED/TVC desalination plants that are responsible for their recent market emergence and competition to the MSF desalination plants will also be reported. Thermal desalination plants are normally associated with power generation cycles. The evolutionary developments of the power/water cogeneration cycles will be discussed at length. Salient features of conventional power water cogeneration cycles in which the MSF distillation plant operates in association with either extraction or condensing or back pressure steam turbines, or in association with combined gas /vapor power generation cycles, will be reviewed. Characteristics of hybrid desalination processes