Eventos Anais de eventos
ENCIT 2016
16th Brazilian Congress of Thermal Sciences and Engineering
Cavity receiver conception for chemical reactors using solar energy
Submission Author:
José Roberto Simões Moreira , SP , Brazil
Co-Authors:
Luciano Nigro
Presenter: José Roberto Simões Moreira
doi://10.26678/ABCM.ENCIT2016.CIT2016-0294
Abstract
The purpose of this work is to study a cavity receptor for chemical reactions. Solar energy is concentrated in such device, which absorbs thermal radiation, transforming it in thermal energy, used to activate chemical reactions. Therefore, the cavity receiver can be used to convert solar energy into chemical energy. The proposed chemical product is hydrogen gas. The first step of this work was an assessment of metal/oxides pairs studied in literature, which can be used to activate thermochemical cycles for hydrogen production. These pairs were compared based in four parameters essentials to cavity receptor design: reaction temperature, physical state of the reactants and products, material resistance to several cycles; hydrolysis reaction rate and other aspects. The chosen pair, rated as the higher average in all parameters, was the pair tungsten and tungsten trioxide (W/WO3). A standard reactor was defined, which was studied regarding cavity reactor performance. By such analysis, it was possible to determine the main design parameters, therefore, cavity aperture, window transmissivity, and the cavity geometric dimensions. Moreover, an efficiency assessment was described. The results allowed establishing a mathematical model in which solar energy can be converted in useful energy for chemical processes, inside a cavity receptor. Given a profile of solar energy concentration, it was calculated absorption and energy lost efficiencies, related to a solar concentration field and radiation available. This method can be used in tandem with available methodologies and data of solar energy predictions, allowing estimations of hydrogen production via solar powered thermochemical cycles.
Keywords
Solar Energy, Cavity receiver, Hydrogen
