Design and analysis of a thermolysis reactor for scaled-up copper-chlorine hydrogen production cycle

Abstract

Alternative hydrogen production methods are being explored with the goal of finding efficient and economical process. The copper-chlorine (Cu-Cl) cycle for hydrogen production has been the focus of the Clean Energy Research Laboratory (CERL) at the University of Ontario Institute of Technology (UOIT). The Cu-Cl cycle has lower thermal energy requirements compared to other methods and utilizes waste heat from power plants and/or some industrial processes. The cycle includes the electrolysis, hydrolysis and thermolysis reaction steps. Decomposition of copper oxychloride (CuOCuCl2) occurs in the thermolysis reactor between 480°C and 530°C. A thermolysis reactor design is presented here with the purpose of scaling it up for a pilot plant of the Cu-Cl process. Transient thermal simulations were conducted with 2.0kg of cuprous chloride (CuCl), single and dual heating sources, and 1, 2 and 4 Wm-2K-1 internal surface convection rates. The dual heater configuration provided the required temperature distribution to allow decomposition to occur. Experimental data with dual heat sources showed that surface temperatures reached 531°C ± 14.0°C. Faster heating was observed with granular CuCl in comparison to solidified CuCl, because the material was allowed to mix in the reactor while it was melted. Simulations with 10.35kg CuCl confirmed adequate surface temperatures for decomposition at low convection rates. Fouling in the phase separation section was observed: XRD analysis showed that the bottom was crystalized CuCl while the upper section was a mixture of predominately CuCl2 dihydrate and CuCl. The vapor production was due to temperatures exceeding 530°C at the CuCl-crucible interface.