EAJ - Artigos publicados em periódicos
URI Permanente para esta coleçãohttps://repositorio.ufrn.br/handle/1/2966
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Navegando EAJ - Artigos publicados em periódicos por Assunto "Chemical looping reforming"
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Artigo Study of the reactivity by pulse of CH4 over NiO/Fe-doped MgAl2O4 oxygen carriers for hydrogen production(Elsevier, 2017-09-28) Melo, Marcus Antônio de Freitas; Medeiros, Rodolfo Luiz Bezerra de Araújo; Macedo, Heloísa Pimenta de; Figueredo, Gilvan Pereira de; Costa, Tiago Roberto da; Braga, Renata Martins; Melo, Dulce Maria de AraújoThe reactivity of Ni-based oxygen carrier (OC) was studied by CH4 pulse test. The MgAl2O4 spinel was synthesized by microwave assisted combustion method and Ni and Fe were added by wet impregnation method. The results of CH4 pulse test revealed that the OCs were more reactive for partial oxidation reaction. The XRD analysis of OCs after the test confirms the presence of NiO and MgAl2O4 without the secondary phases like NiAl2O4 and FeAl2O4. Among the OCs, Ni15Fe2MA was the most reactive producing the highest amounts of H2 and exhibiting good re-oxidation capacity, illustrating its potential for use in Chemical Looping Reforming (CLR). The high reactivity is associated to a change on the NiO-support interactionArtigo Study of the reactivity of Double-perovskite type oxide La1¡xMxNiO4 (M 1⁄4 Ca or Sr) for chemical looping hydrogen production(Elsevier, 2018-01-18) Melo, Marcus Antônio de Freitas; Melo, Vítor Rodrigo de Melo e; Medeiros, Rodolfo Luiz Bezerra de Araújo; Braga, Renata Martins; Macedo, Heloísa Pimenta de; Ruiz, Juan Alberto Chavez; Moure, Gustavo Torres; Melo, Dulce Maria de AraújoLa2-xMxNiO4 perovskite oxygen carriers (OC) doped with Ca and Sr (x 1⁄4 0.05 and 0.20) in the site La were prepared by microwave assisted combustion method and calcined at 800 C for 2 h. A reactivity study was carried out applying pulses of H2, O2 and CH4. The reactions involved in each step, as well as H2 production, were studied to evaluate the redox properties of each OC. The crystalline structure, morphology, reduction and oxidation profiles were determined by XRD, SEM and TPR/TPO cycles, respectively. The results indicate that the dopant (Ca or Sr) strongly affect the structure and reactivity of the OC. The increase in dopant concentration increased the degree of crystallinity and the amount of the A2BO4 phase formed. The increase in dopant concentration decreased the reducibility of the perovskite. OCs doped with Ca showed higher conversion percentages, and also higher H2 production. In carriers doped with Sr no coke formation was observed.