Insights into utilization of strontium carbonate for thermochemical energy storage

The reversible dissociation/carbonation of metal carbonates, performed in fluidized bed reactors, is one of the most promising technological solution for thermochemical energy storage (TCES) in concentrating solar power plants (CSP). In this framework, the SrCO3/SrO system is receiving increasing interest due to its high energy density (4 GJ/m3) and working temperatures (up to 1200 ?C). As the more investigated CaCO3/CaO couple, also SrO undergoes a dramatic drop of reactivity over multiple carbonation/calcina- tion cycles due to sintering. Even though the potentiality of this system has already been proved by thermo-gravimetric analyses, its actual reaction performances in a fluidized bed are strongly dependent on the gas-solid contact efficiency and heat/mass transfer between the gaseous and solid phase. In this work, the cyclic carbonation/calcination of the SrO/SrCO3 system for TCES-CSP has been investigated by thermo-gravimetric analysis and, for the first time, in a lab-scale fluidized bed rig, thus providing useful applicative insights. A new Al2O3-stabilized composite has been synthesized, i.e. Al2O3 has been added to SrO/SrCO3 system as both sintering inhibitor and flow conditioner. In particular, composite materials with different Al2O3/SrO composition have been synthesized to investigate the ef- fect of the inhibitor amount on both the fluidizability and energy storage performances.