Título
Evaluation of NiWO4 as an oxygen carrier for the hydrogen storage by chemical looping.
Autor
MIGUEL JESUS MELENDEZ ZARAGOZA
Jesús Manuel Salinas Gutiérrez
Alejandro López Ortíz
VIRGINIA HIDALINA COLLINS MARTINEZ
Pedro Eloy Gonzalez Vargas
Nivel de Acceso
Acceso Abierto
Materias
Resumen o descripción
Chemical looping process (CL) have recently been used for various purposes, one of which is the hydrogen storage using metal oxides (MeO) as the only source of oxygen (oxygen carriers) to produce water (MeO + H2 = Me + H2O) and regenerating the metal oxide with a steam oxidizing atmosphere for the hydrogen release (Me + H2O = MeO + H2). It is important that these oxygen carriers have certain characteristics to be used for this purpose, such as thermal stability and the ability to store and release the lattice oxygen to the cyclic reaction conditions. In order to evaluate the nickel tungstate (NiWO4) for this purpose, it was thermogravimetrically tested (TGA) in three
accelerated redox cycles using a mixture of 5 v% of H2/Ar as a reducing atmosphere and a mixture of 5 v% H2O/Ar gas stream as the oxidizing atmosphere. Characterization made to the material before and after the redox cycles were performed by XRD, BET surface area, and SEM and have shown its favorable potential as an oxygen carrier when testing its thermal and reactive stability after three consecutive redox cycles. TGA tests revealed an oxidation mechanism of the reduced metals (Ni + W) that follows a reaction path, which consists in the formation of WO3 by the oxidation of W with steam, followed by the formation of NiWO4. This reaction path was confirmed by thermodynamic calculations that indicate that the oxidation of Ni, WO3 and steam is presumably the rate-determining step.
Fecha de publicación
2018
Tipo de publicación
Memoria de congreso
Recurso de información
Formato
application/pdf
Idioma
Inglés
Repositorio Orígen
Fuente de Objetos Científicos Open Access
Descargas
402