Azeotropic distillation of hydrochloric acid in the copper-chlorine cycle for hydrogen production

In this paper, azeotropic distillation is investigated for concentrating HCl(aq) between the electrolysis and hydrolysis processes of the copper-chlorine cycle for hydrogen production. Recent progress on the cycle suggests HCl(aq) will need to be concentrated through its azeotrope, which cannot be achieved with typical distillation techniques. A heated distillation system is designed and constructed to investigate the distillation process on both sides of the azeotrope to collect new data for azeotropic distillation of HCl(aq). The distillation system consists of one packed distillation column with heating tapes and thermocouples to achieve a desired axial temperature profile. The column can be operated in batch or continuous mode. The HCl concentrations of the output products are determined by measuring the concentration of Cl−(aq) ions.