Conference Proceedings: SolarPACES 2019
SOLPART participated in the 25th edition of SolarPACES, which took place in Daegu, South Korea from 1 to 4 October 2019.
In this context, two SOLPART partners gave presentations about the project, which are now featured in the SolarPACES 2019 Conference Proceedings, published in December 2020:
Authors: Thibaut Esence, Emmanuel Guillot, Michael Tessonneaud, Antoine Saraiva, Alex Le Gal, Mouâd Elidrissi, Damien Poncin, Jean-Louis Sans and Gilles Flamant (CNRS-PROMES)
Cite as: AIP Conference Proceedings 2303, 170006 (2020); https://doi.org/10.1063/5.0028763
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.
Authors: Stefania Tescari, Pradeepkumar Sundarraj, Gkiokchan Moumin, Juan Pablo Rincon Duarte, Christos Agrafiotis, Lamark de Oliveira, Christian Willsch, Martin Roeb and Christian Sattler (DLR, TU Dresden)
Cite as: AIP Conference Proceedings 2303, 140007 (2020); https://doi.org/10.1063/5.0029271
Abstract: Rotary kilns are very robust and versatile reactors and can be used on solar towers to perform high-temperature endothermic thermal decomposition reactions of solid materials with the aid of concentrated solar irradiation. Their easy functioning system allows flexibility with respect to a wide range of operating conditions, such as particle size, residence time, operating temperature, furnace atmosphere etc. In the present study, two different solid materials with different particle sizes are successfully treated to demonstrate the versatility of this reactor: redox oxide granules of mm size are thermally reduced for high temperature thermochemical storage and micrometric particles of CaCO3 are calcined to produce lime (as the main ingredient of cement). Preliminary tests for using the rotary kiln in thermochemical storage were carried out in a closed-chamber configuration, where the reactor atmosphere is separated from the environment. The increase in the oxygen concentration in the outlet gas could clearly indicate the onset and progress of chemical reaction. The increase in residence time has been identified as the key point for increasing the conversion of the solid material. Calcination of CaCO3 was demonstrated in 13 chemical experiments. The heat losses mechanisms have been studied and pointed out that the suction of gas should be optimized to increase the efficiency of the reactor. It has also been shown that the reactor efficiency can be increased by reducing the material conversion. Optimal operation therefore depends on the final target application.