A Novel Hydrogen Economy Based on Electrochemical Cells Fully Integrated With Fossil Fuel Assets and Wastewater Resources

Abstract

Water and energy are two inseparable and interdependent phenomena that play essential roles in economic productivity and sustainable development. This paper presents a novel, highly efficient, and modular hydrogen production unit that can be fully integrated with numerous power production units, including coal and natural gas-fired power plants. The system is designed to utilize various water sources as the process’s feedstock. All process components, including waste-water treatment system, flue gas cooling, separating unit, and high-temperature solid oxide electrolyzer cell (SOEC), are simulated and integrated using Aspen HYSYS. The SOEC model is first validated with experimental and available numerical data. The validation results show that the model can accurately predict SOEC performance at various operating conditions. Afterward, various system configurations are presented, and a comprehensive process analysis has been implemented to evaluate the effects of operating and design parameters on the system performance and efficiency of 97.4% for the SOEC. The overall thermal-to-hydrogen efficiency of the system is 56.3% without heat integration. Moreover, this novel process is integrated with renewable energy sources to ensure the system contribution to global energy decarbonization. Finally, a cradle-to-gate life cycle assessment (LCA) is performed to analyze the environmental impacts of the proposed system. The results indicate that the overall damage level is almost 50% higher using coal power plant as electricity source as to the solar PV and that water-energy nexus is eminent in energy sustainability, water preservation, and the prospect of this integrated system.