Optimal configuration of low-grade waste heat driven seawater desalination using data envelopment analysis: A case study of industrial application

Abstract

Water supply challenges are caused by population growth, industrialization, as well as the scarcity of freshwater resources. Low-grade waste heat-driven seawater desalination technologies may improve the water-energy nexus issues of desalination systems by different configurations. The data envelopment analysis is used to determine the best final decision to achieve a better comparison of different parameters. The optimal configuration of low-grade waste heat driven seawater desalination is studied using flue gas waste heat in heat recovery boilers of an industrial oil refinery. Nine different types of multistage flash and multi-effect distillation (MED) desalination plants have been considered. The results show that the multistage flash brine recirculation may produce more desalinated water while the multi-effect distillation with three stages (3-stage MED) has the best payback period. Using 3-stage MED with a production of approximately 19,630 kg/h of water from 5.3 MW exhaust gas is more suitable for this design. Thus, the proposed strategy guides us toward the best decisions to configure low-grade waste heat-driven desalination plants for better design considering rigorous simulations for the plants. Moreover, this framework enables us to consider different criteria of technical, economic, and environmental issues for optimal configuration.