Abstract:

Thermochemical energy storage (TCES) technology holds promise for a civilization that wants to run solely on renewable sources. The Ca(OH)₂/CaO TCES system based on calcium looping has attracted a lot of attention due to its high energy storage density, prolonged energy storage period, and environmental friendliness. An experimental platform of direct and indirect mixed heating fixed-bed reactors was established in this study. A typical heat storage/release experiment under an air atmosphere was carried out in order to investigate the mixed heating reactor's heat storage characteristics and limiting constraints. In light of this, on this basis, a workable plan to enhance the cycling performance at the reactor scale was investigated. The experimental investigation of heat storage demonstrates that the combination of centripetal and layer-by-layer advancements can be achieved by using direct and indirect mixed heating, which accelerates the rate of energy storage response. The heat storage and release continuous trials show that the conversion rate of energy storage reaction drops by 5.6% after five cycles, and the maximum conversion rate of ten cycles decreases by 3.8% compared with five cycles. The reaction performance gradually declines with more cycles. TG and particle size test findings indicate that the CO₂ of air is the primary cause of the decline in cycling performance. The reaction performance recovery experiment in the energy storage stage demonstrates that raising the dehydration temperature can successfully restore the cycle performance, and the excess temperature provided at 650 ℃ can successfully lower the content of CaCO₃ in the reactant.

Key words: thermochemical energy storage, Ca(OH)₂/CaO, reactor, experiment research