Interfacial thermodynamics and X-ray diffraction of hydrolysis products in multiphase reacting flow of the Cu–Cl cycle

This paper examines the chemical equilibrium and gaseous product fraction of a multiphase gas–solid flow involving hydrolysis of copper (II) chloride and steam in a packed bed reactor. The effectiveness of the water splitting process has a significant impact on the efficiency of the thermochemical copper–chlorine (Cu–Cl) cycle for hydrogen production. A thermodynamic analysis of the HCl fraction in the gaseous effluent is presented, along with a predictive model of solid particle conversion based on the reaction temperature and pressure. Experimental results are presented for a horizontal packed bed reactor which exposes a low steam flow rate to a large volume of solid CuCl2 in the packed bed reactor. The predicted and experimental results demonstrate that an HCl fraction above 0.3 can be achieved within the hydrolysis reactor, thus allowing effective integration between hydrolysis and downstream electrolytic hydrogen production steps in the Cu–Cl cycle, without costly HCl/steam separation processes.

► The hydrolysis exit stream in the Cu–Cl cycle can achieve an HCl fraction above 0.3.
► A process of separating HCl gas and steam can be removed from the Cu–Cl cycle.
► The variation of HCl fraction with system temperature and pressure is predicted.