Characterization of a pilot fluidized bed reactor for solar calcination processes

Nowadays, the calcination of mineral particles is mainly performed by burning carbonaceous fuels. Consequently, this process is the second source of carbon dioxide emission worldwide. This study, developed in the framework of the SOLPART H2020 project, proposes a new concept of reactor-receiver for continuous calcination processes using concentrated solar energy. A pilot fluidized bed reactor has been designed and is currently under testing at the CNRS’s 1MW solar furnace. The first experimental results corresponding to the reactor-commissioning phase show the feasibility of continuous calcination processes in a solar fluidized bed reactor. A particle mass flow of around 20 kg/h of calcite has been decomposed into lime with a conversion degree around 20%. A numerical model has been developed and is still to be validated with more complete experimental data. A preliminary parametric study performed with the model shows that the conversion degree of the calcination process is strongly influenced by the mean residence time of the particles. Moreover, there is an optimal particle mass flow rate that maximizes the chemical efficiency of the system. This corresponds to a compromise between the reaction extent and the equilibrium temperature of the reactor.