(613b) An Integrated Approach to Water-Energy Nexus with Multiple Energy Sources

Fadhil Y. Al-Aboosi and Mahmoud M. El-Halwagi

The Artie McFerrin Department of Chemical Engineering

Texas A&M University

College Station, Texas 77843-3122

ABSTRACT

Growing energy demand, water scarcity, and climate change have emerged as considerable challenges to sustainable development. Consequently, there is a necessity to create the proper management strategies for water resources (e.g., wastewater treatment) and to integrate conventional energy sources with renewables (e.g., solar energy, wind energy, biofuels, etc.). The objective of this study is to develop a design framework for integrating water and energy systems including multiple energy sources, cogeneration process, and desalination technologies. Solar energy is included to provide thermal power directly to a multi-effect distillation plant (MED) exclusively (to be more feasible economically) or indirect supply through a thermal energy storage system. Thus, MED is driven by direct or indirect solar energy, and excess or direct cogeneration process heat. The proposed thermal energy storage along with the fossil fuel boiler will allow for the dual-purpose system to operate at steady-state by managing the dynamic variability of solar energy. Additionally, electric production is considered to supply a reverse osmosis plant (RO) without connecting to the local electric grid. A multi-period mixed integer nonlinear program (MINLP) is developed and applied to discretize operation period to track the diurnal fluctuations of solar energy. The solution of the optimization program determines the optimal mix of solar energy, thermal storage, and fossil fuel to attain the maximum annual profit of the entire system. A case study is solved for water treatment and energy management for Eagle Ford Basin in Texas.

Keywords: Cogeneration, Process integration, Solar energy, Thermal storage, Desalination, Optimization