The favourable thermodynamic properties of Fe-doped CaMnO3for thermochemical heat storage
[EN]The CaMnO oxide can reversibly release oxygen over a relatively wide range of temperatures and oxygen partial pressures (pO) and is thus a promising candidate for thermochemical heat storage in Concentrated Solar Power (CSP) plants. Moreover, it is composed of earth-abundant, inexpensive and non...
| Autores: | , , , |
|---|---|
| Formato: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2020 |
| País: | España |
| Recursos: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/229435 |
| Acesso em linha: | http://hdl.handle.net/10261/229435 |
| Access Level: | acceso abierto |
| Palavra-chave: | Concentrated Solar Power (CSP) plants CaMnO CaFeMnO Heat storage |
| Resumo: | [EN]The CaMnO oxide can reversibly release oxygen over a relatively wide range of temperatures and oxygen partial pressures (pO) and is thus a promising candidate for thermochemical heat storage in Concentrated Solar Power (CSP) plants. Moreover, it is composed of earth-abundant, inexpensive and non-toxic elements and exhibits a high-energy storage density, which are desirable characteristics for decreasing the deployment costs of the system. However, it undergoes decomposition atpO≤ 0.008 atm and temperature ≥ 1100 °C. Here the possibility of overcoming this limitation and extending the operating temperature range by B-site doping with Fe (CaFeMnO) is explored. Two doping levels are investigated,x= 0.1 and 0.3. The enthalpy of reduction was determined from a measurement of continuous equilibrium non-stoichiometry curves (δ,T) at severalpO, enabling an evaluation of the heat storage capacity with high accuracy over widely ranging oxygen non-stoichiometry. Introduction of 0.1 Fe (CaFeMnO) prevented CaMnO decomposition up to 1200 °C atpO= 0.008 atm, thus widening the operating temperature range and the oxygen reduction extent. The increase in the accessible nonstoichiometry translates into an increase in the heat storage capacity (Q(kJ mol)) from ∼272 kJ kgin CaMnOto ∼344 kJ kgin CaFeMnOWhile even larger changes in oxygen content were accessible in CaFeMnO, the oxidation state changes are accompanied by a lower enthalpy of reduction, resulting in a diminished heat storage capacity of ∼221 kJ kg. |
|---|