Research subject: The growing global water crisis has intensified the need to advance desalination technologies. In this regard, thermal desalination methods such as Multi-Stage Flash (MSF) and Multi-Effect Distillation (MED) are considered suitable options in regions where saline water sources are located near petrochemical and refinery plants. Their suitability stems from their capability to utilize low-grade thermal energy sources, such as flue gases from industrial processes.
Research approach: This study investigates and compares the performance of MSF and MED technologies within a flue gas heat recovery scenario. A detailed mathematical modeling framework is developed for both systems, incorporating mass and energy balance equations, heat transfer mechanisms, and economic evaluation metrics. The models are validated through comparison with experimental data obtained from various industrial units to ensure reliability and accuracy.
Main results: Simulation outcomes show that MSF, operating at a 50% recovery rate using flue gas as a heat source, has a water production cost of approximately $0.80 per cubic meter, while MED, under similar conditions, achieves a lower cost of $0.40 per cubic meter. Furthermore, the specific energy consumption is calculated to be about 15.9 kWh/m³ for MSF and 11.3 kWh/m³ for MED. Greenhouse gas emissions in the MED system are estimated to be 41% lower than in MSF at the same recovery level. From an environmental standpoint, the pollutant intensity of the concentrated brine generated by the two technologies is essentially the same. Overall, MED demonstrates superior performance over MSF in the context of flue gas heat recovery integration, due to its lower energy consumption, reduced operational cost, decreased greenhouse gas emissions, and minimized environmental impact. This study provides a comprehensive and validated numerical framework that can support simulation-based optimization of thermal desalination systems for sustainable water production.