Optimal design of a hybrid RO/MSF desalination system in a non-OPEC country

The hybrid process of seawater desalting couples the reverse osmosis with the multi-stage flash process. The hybrid process is usually planned to improve the performance of MSF and reduce the cost of desalted water. Most of the studies on these plants refer to the parameters (both technical and economical) that have been obtained in the countries where desalination processes are in common use. In general, these are also the countries where low cost energy is more available. That is why these results can hardly be compared to those of countries having limited energy resources. Our aim in this paper is to compare the costs to be calculated for a hybrid desalination system in the two situations cited. Our objective is to study the system in order to calculate the minimum water production cost as a function of the main parameters of the MSF section. Calculations are carried out using two different values of the energy cost (fuel and electric energy) as well as for two different flow rates of the desalted water produced by the plant. Therefore, our calculations allow us to compare the production cost of desalinated water in a country with large amounts of energy resources (for example an Opec country) with that of a non-Opec country.