Experimental Study on the Mechanism and Kinetics of CuCl2 Hydrolysis Reaction of the Cu–Cl Thermochemical Cycle in a Fluidized Bed Reactor

Hydrolysis of CuCl₂ is the water splitting step of the Cu–Cl thermochemical cycle, where CuCl₂ reacts with steam to produce Cu₂OCl₂ and HCl. In the present work, this gas–solid reaction was investigated to understand the mechanism and kinetics. Experiments were conducted in a semibatch fluidized bed reactor to study the effect of temperature (275–375 °C), steam mole fraction (0.4–0.9), and reaction time (0–3 h). The challenges due to the hygroscopic nature of the reactant, product agglomeration, and multiple side reactions to achieve smooth and consistent reactor performance were overcome by the addition of inert additives during fluidization. The analysis of the mechanism showed that the desired product Cu₂OCl₂ is formed initially and further undergoes decomposition to CuO and CuCl₂. Also, with increasing temperatures, the yield of Cu₂OCl₂ decreases because of the formation of CuCl from reactant decomposition. The results indicate that a minimum steam mole fraction of 0.5 is required to prevent the formation of side product CuCl in the temperature range of 300–325 °C. The minimum steam requirement for maximum yield to Cu₂OCl₂ was found to increase with increase in temperature.