Experimental and numerical studies of Ca(OH)2/CaO dehydration process in a fixed-bed reactor for thermochemical energy storage

The Ca(OH)2/CaO thermochemical energy storage (TCES) system based on calcium looping has received extensive attention owing to its high energy storage density, prolonged energy storage time, and environmental friendliness. The heat storage process of the Ca(OH)2/CaO TCES system in a mixed heating reactor was evaluated in this study, by employing a combination of direct and indirect heating modes. The dehydration process was studied experimentally, and a numerical model was established and verified based on the experimental results. The dehydration behavior of 500 g of Ca(OH)2 powder was investigated in a fixed-bed reactor with mixed heating. The experimental and simulation results indicated that mixed heating causes combined centripetal and horizontal propulsion. Heat input is the main limiting factor in the heat storage process, because the radial advance of the reaction is hindered by the low thermal conductivity of the solid reactant particles. Heat transmission partitions were added to enhance the performance of the reactor. The performance of the modified reactor was compared with that of a conventional reactor. The radial heat transmission partitions in the modified reactor effectively enhance the energy storage rate and reduce the reaction time by 59.5% compared with the reactor without partitions.