Kinetics and thermal effects on particle reaction rates in hydrolysis of the copper–chlorine cycle

The copper-chlorine (Cu–Cl) cycle is a promising thermochemical water-splitting process for hydrogen production. In this paper, CuCl 2 solid particles in the hydrolysis reaction of the Cu–Cl cycle are examined over a range of operating temperatures and steam-to-copper ratios. A shrinking core model (SCM) is used to analyse the particle conversion process. Experiments are also conducted within a vertical semi-batch fixed bed reactor. Dried particles have the lowest overall conversion, compared to crushed or crystallised samples. Further X-ray diffraction (XRD) examination examined the reaction products between 370 and 400 °C. Activation energies ranged from 32 to 54 kJ/mol. This paper establishes a direct correlation between reduction of the steam-to-copper ratio and subsequent conversion. The results provide useful new insight into the hydrolysis reaction of the Cu–Cl cycle. • Cu–Cl cycle hydrolysis varies by temperature and steam-to-copper ratio. • Crushed CuCl 2 has the highest conversion rate, while dried samples the lowest. • The activation energies for the hydrolysis reaction range from 32 to 54 kJ/mol.