Thermo-economical modeling and multi-objective optimization of thermal energy driven multiple effect distillation system for water treatment using NSGA-II Algorithm

Abstract

This study presents a thermoeconomic model for optimizing the operation of a Multiple Effect Distillation (MED) system driven by thermal energy. By evaluating configurations with 2-, 4-, and 6-effects, the research aims to enhance distillate output (DO) while minimizing the Cost of Distillate (COD). Key parameters such as motive steam flow rate, steam pressure, and feed water temperature are investigated to determine their impact on system performance. Comparative analysis reveals significant increases in distillate output with additional effects, notably a 27 % rise with 4 effects and a further 34 % increase with 6 effects. Moreover, as the number of effects increases, there is a corresponding elevation in the minimum operating pressure of motive steam, narrowing the operating pressure range. The study identifies the 6-effect MED system as the optimal configuration, balancing thermal efficiency and economic feasibility by offering a wider range of steam flow rates while minimizing operating pressure. Furthermore, the research highlights the importance of maintaining an optimal feedwater temperature of 80 0C to avoid reduced distillate output and increased COD.