Integrating hybrid systems with existing thermal desalination plants

In Gulf countries, most power plants are co-generation power desalting plants (CPDP) that generate electric energy and also produce fresh water through the desalination of seawater. This paper provides detailed technical and economical analyses to evaluate a new generation of dual purpose technology that includes the integration of reverse osmosis (RO) processes with existing thermal desalination processes and power generation (triple hybrid system) at Layyah plant, Sharjah, UAE. Hybridization of sweater reverse osmosis (SWRO) and the multi-stage flash (MSF) technology was considered to improve the performance of latter and reduce the cost of the produced water. Moreover, “idle” power in winter (seasonal surplus of unused power) was mainly utilized by RO to further reduce the cost of the hybrid system for six months of the year. Spinning reserve was also used to further reduce the cost of the proposed hybrid system. Integration of the three processes of MSF, MED, and RO desalination technologies could be made at different levels through which the resulting of water cost will depend on the selected configuration and the cost of materials of construction, equipment, membrane, energy, etc. Thus, the capital and annual operating costs were calculated for all potential alternatives for various plant capacities. It was found that for all plant capacities, integrated hybrid systems resulted in most cost effective solution. For example, at a capacity of 50 MIGD, the present worth of the cost was calculated to be 588.7, 443.2, and 380 million US$ for MSF, MED, and hybrid RO systems, respectively.

Several aspects of engineering management were applied to integrate essential daily resources in the Emirate of Sharjah. The resources tackled in this work include water, power, and fuel. These resources influence each other and should be optimized and allocated simultaneously. Engineering problem solving approach was pursued. Data search and collection, technology selection, load management, water demand, power demand, and fuel availability were all used to come up with optimum scenarios to reduce cost of power and water generation and to meet increasing demand of water and power. Unique features of this work include: Fig. 11. Present worth cost of desalination technologies.