A fundamental study on the mechanistic impact of repeated de- and rehydration of Ca(OH)2 on thermochemical cycling in technical scale

A major scientific challenge for carbon neutral, environmental friendly future energy production is the development of renewable energy production to technological readiness. One example are solar thermal power plants. Since their energy generation is intermittent, they demand for a feasible storage solution for which thermochemical reaction systems are considered. The present work subjects the thermochemical reaction system CaO / Ca(OH)2 and its structural-mechanical correlations impacting the powder bulk performance upon thermochemical cycling. On exemplified Ca(OH)2 crystals is shown, that during the first de- and rehydration process, the entire crystal morphology is disintegrated. The underlying mechanism is evaluated by theoretical considerations on the layered structure of Ca(OH)2 and validated by scanning electron microscopy (SEM) on the probed material before and after dehydration as well as after rehydration. The obtained findings are transferred to the technically relevant po