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Abstract
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One method to provide pure water is using diesalination method in which salinity and other minerals are taken out of the seawater. The main goal of this thesis is to desalinate the seawater with dissipated heat from a gas engine with nominal power capacity of one electrical MW. Heat of the engine jacket and exhaust are equal to 800 KW and 700 KW respectively. In this way two methods of Humidification and Dehumidification (HDH) and Zero Liquid Discharge (ZLD) is presented. In order to desalinate the seawater, multiple systems are designed and to evaluate them, a thermal analysis is conducted using mass and energy conservation with some applied constraints. Also, the efficiency of proposed systems is computed in different operational conditions and the optimized amount of fresh water is calculated. If the top temperature of the humidifier tower reaches to 50 degrees of Celsius, the freshwater flow rate for HDH system and hybrid HDH-ZLD system will be 1.9 Kg/s and 2.2 Kg/s. The results show that the designed systems recovered the engine heat which results in energy saving and massive production. Finally, an economical analysis by El-Dessouky and Ettouney Method (EEM) is conducted on a HDH system and composite HDH-ZLD, and also the optimized system is presented. The best mood of the hybrid system occurs at 80 °C, in which the product cost is 0.7 $/m3. Because of crystallizer and heat exchanger eliminating in a simple HDH system, in spite of pure water production, the product cost is reduced 60 cents.
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