Process Configuration to Make Desalination Carbon-Neutral and Zero-Discharge: Modeling, Optimization, and Energy Intensification

Abstract

This work proposes an innovative process configuration to transform seawater desalination into a carbon-neutral zero liquid discharge technology. To decouple the energy-water-environment nexus of the widely used multieffect desalinator, a solar collector is retrofitted along with vapor compression systems. Further, an organic Rankine cycle is developed for process integration with the solar system and the existing steam boiler, which leads to producing surplus electricity and bringing down the carbon emission to near-zero. This surplus electricity, along with the untapped thermal energy in the discharge brine, is utilized to operate a zero liquid discharge system, achieving brine elimination and enhanced potable water production simultaneously. A theoretical framework is formulated to represent the seawater desalinator, and validated using data sets of three plants operated in Kish Island (Iran), Tripoli (Libya), and Umm Al-Nar (UAE). A genetic algorithm is strategized to determine the globally optimal parameters of the desalination system. This decarbonized desalination technology is sustainable, cost-effective, and environmentally friendly, featuring high water recovery.