Sea water intake and its effect on heat rejection design and material for flash distillation plant

Abstract

The suspended matter in sea water play a big role in the design of sea water intake and heat rejection section. The sea water intake usually depends on the shore nature and quality of sea water. Chemical treatment can handle marine growth and bacteria but the suspended matter in the sea water need further treatment usually by settling basin and screens, these are normally costly and need minimum plant size to prove its economical aspects. For relative small installation up to about 15 MIGPD Plant other solution can be adopted in the sea water design and choice of materials of heat rejection section. In case of sea water having suspended sand higher than certain sizes and quantity with large temperature differences between summer and winter and tubes of copper bases will lead to either over design of the heat rejection flash stages or providing recirculating sea water facilities between the outlet and inlet of the heat exchanger of the heat rejection section. Comparison has been carried out for cupro-nickel tubes and titanium tubes with and without settling basin respectively and comprehensive study and analysis has been done as well as discussion on cost, operation procedures, limit of parameters such as velocities, corrosion deposit, erosion and fouling etc. Recommendation and conclusion are given.