Development of new heat exchanger network designs for a four-step Cu–Cl cycle for hydrogen production

The Aspen Plus process simulation package is used to evaluate the characteristics of the four-step Cu–Cl thermochemical water splitting cycle in terms of energy and exergy, to support the ultimate development of a pilot plant. Alternative designs for the heat exchanger network using Aspen Energy Analyzer are developed and studied for thermal management within the Cu–Cl cycle. The simulation results for the four-step Cu–Cl cycle illustrate that the steam-to-copper molar ratio can be reduced to 10 from an initial value of 16 by decreasing the pressure of the hydrolysis reactor. A thermodynamic model of the four-step Cu–Cl cycle is developed to determine its energy and exergy efficiencies. The energy and exergy efficiencies of the four-step Cu–Cl cycle are determined to be 55.4% and 66.0%, respectively.