Modeling of a CeO2 thermochemistry reduction process for hydrogen production by solar concentrated energy

• Main Authors: Valle-Hernández, Julio, Romero-Paredes, Hernando, Arancibia-Bulnes, Camilo A., Villafan-Vidales, Heidi I., Espinosa-Paredes, Gilberto
• Format: Conference Proceeding
• Language: English
• Subjects: Carrier gases; Cerium oxides; Computational fluid dynamics; Computer simulation; Energy transfer; Exothermic reactions; Fluid mechanics; High temperature; Hydrogen; Hydrogen production; Hydrolysis; Innovation; Mathematical models; Nuclear fuels; Pipes; Porous media; Reaction products; Solar energy; Solar furnaces; Temperature distribution; Thermal reduction; Thermochemistry; Tungsten
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/1.4949210

In this paper the simulation of the thermal reduction for hydrogen production through the decomposition of cerium oxide is presented. The thermochemical cycle for hydrogen production consists of the endothermic reduction of CeO2 at high temperature, where concentrated solar energy is used as a source of heat; and of the subsequent steam hydrolysis of the resulting cerium oxide to produce hydrogen. For the thermochemical process, a solar reactor prototype is proposed; consisting of a cubic receptacle made of graphite fiber thermally insulated. Inside the reactor a pyramidal arrangement with nine tungsten pipes is housed. The pyramidal arrangement is made respect to the focal point where the reflected energy is concentrated. The solar energy is concentrated through the solar furnace of high radiative flux. The endothermic step is the reduction of the cerium oxide to lower-valence cerium oxide, at very high temperature. The exothermic step is the hydrolysis of the cerium oxide (III) to form H2 and the corresponding initial cerium oxide made at lower temperature inside the solar reactor. For the modeling, three sections of the pipe where the reaction occurs were considered; the carrier gas inlet, the porous medium and the reaction products outlet. The mathematical model describes the fluid mechanics; mass and energy transfer occurring therein inside the tungsten pipe. Thermochemical process model was simulated in CFD. The results show a temperature distribution in the solar reaction pipe and allow obtaining the fluid dynamics and the heat transfer within the pipe. This work is part of the project “Solar Fuels and Industrial Processes” from the Mexican Center for Innovation in Solar Energy (CEMIE-Sol).