Thermoeconomic analysis of seawater desalination methods in Bandar Abbas power plant

The purpose of this study is to obtain the optimal desalination system with economic approach and the least production pollution for the conditions of Bandar Abbas power plant. For optimal use of the returns of desalination units, five different arrangements of the combination of multi-effect desalination with thermal vapor compression (MED_TVC) and reverse osmosis (RO) desalination units were defined and using thermoeconomic equations and genetic algorithms to optimize different states, the final product cost associated with each arrangement was determined by modeling in engineering equation solver (EES), which is highly accurate according to the validation. The motive steam is provided to fuel the heating units from the steam generated in the heat recovery steam generator (HRSG), which increased the exergy efficiency to 2.53% compared to the exergy efficiency of 2.16% in the current state of the power plant that uses an auxiliary boiler. Two approaches are considered to evaluate the final cost of producing 7600 cubic meters per day of water required by the power plant for each of the arrangements. The first approach is for the current capacity of the power plant, and the second approach is for the case where most of the water capacity is produced by RO. The final results show that the second and fourth arrangements in both approaches have the lowest cost of water production with a slight difference. Also, these two arrangements have higher exergy efficiency than the other arrangements. The second approach showed the higher share of water production by RO, the lower final cost of production, and the best mode is when all the water is supplied by the RO unit, so that the final cost of the product is reduced from 2.59 to 0.59 dollars per cubic meter.