Mathematical modeling of a thermally driven multistage desalination system (MED) for industrial applications

Abstract

Multi-Effect Distillation (MED) systems are advanced technologies for seawater desalination, valued for their high energy efficiency and heat recovery capabilities in industrial and potable water applications. This study developed a mathematical model based on mass, energy, and thermodynamic balances to analyze system performance. By solving the governing equations, the impact of key parameters—number of distillation stages, inlet steam temperature, and brine concentration—on the Gain Output Ratio (GOR) was quantitatively evaluated. Results show a linear positive correlation between the number of stages and GOR improvement, with a maximum GOR of 12.049 achieved in a 12-stage configuration at an 80°C feed temperature. Each additional stage increases GOR by approximately 15%. However, the motive-to-sucked steam ratio grows exponentially with more stages, significantly increasing motive steam consumption. These findings provide an analytical framework for optimizing industrial MED systems, enhancing energy efficiency and economic savings.