Intrinsic kinetics of CO2 methanation on low-loaded Ni/Al2O3 catalyst: Mechanism, model discrimination and parameter estimation
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Título: | Intrinsic kinetics of CO2 methanation on low-loaded Ni/Al2O3 catalyst: Mechanism, model discrimination and parameter estimation |
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Autor/es: | Quindimil, Adrián | Onrubia-Calvo, Jon A. | Davó-Quiñonero, Arantxa | Bermejo-López, Alejandro | Bailón-García, Esther | Pereda-Ayo, Beñat | Lozano-Castello, Dolores | González-Marcos, José A. | Bueno López, Agustín | González-Velasco, Juan R. |
Grupo/s de investigación o GITE: | Materiales Carbonosos y Medio Ambiente |
Centro, Departamento o Servicio: | Universidad de Alicante. Departamento de Química Inorgánica |
Palabras clave: | CO2 methanation | Ni/Al2O3 catalyst | Kinetic model | Reaction mechanism | H-assisted CO formation route |
Área/s de conocimiento: | Química Inorgánica |
Fecha de publicación: | 13-ene-2022 |
Editor: | Elsevier |
Cita bibliográfica: | Journal of CO2 Utilization. 2022, 57: 101888. https://doi.org/10.1016/j.jcou.2022.101888 |
Resumen: | The mechanism and kinetic of CO2 methanation reaction of 9.5 % Ni/Al2O3 catalyst is analysed under a wide range of operating conditions. Once the catalyst activity is stabilized, the influence of temperature, total pressure and space velocity is studied for kinetic characterisation. A data set comprising of 153 experimental runs has been used to develop a kinetic model capable to accurately predict the reaction rate. Ni/Al2O3 catalyst shows an apparent activation energy of 80.1 kJ mol−1 in CO2 hydrogenation. Data obtained under differential mode adjust quite precisely to a power-law model with H2O inhibition, with a water adsorption constant of 3.1 atm−1 and apparent orders of 0.24 and 0.27 for H2 and CO2, respectively. Based on DRIFTS results, we propose for the first time the H-assisted CO formation route, which is compared with the more conventionally reported carbonyl route, and describe the corresponding reaction rate LHHW equation, resulting in notable improvement for mean deviation (D) of 7.0 % in our model related to that based on the carbonyl route (D = 20.1 %) usually suggested for catalysts with higher Ni loads around 20 %. The H-assisted CO formation route considers the formate species decomposition into carbonyls via H-assisted CO formation mechanism and further carbonyls hydrogenation into CHO as the rate determining step. Thus, the LHHW mechanism, in which carbonyls as well as formate species participate in CO2 methanation, is capable to reflect the kinetics of lowly-loaded Ni/Al2O 3 catalyst with high accuracy under relevant process conditions (315−430 °C, 1−6 bar, H2 to CO2 molar ratios between 1–16 and, different reagents and products partial pressures). |
Patrocinador/es: | Support for this study was provided by the Spanish Ministry of Economy and Competiveness (Project PID2019-105960RB-C21 and PID2019-105960RB-C22) and the Basque Government (Project IT1297-19). One of the authors (JAOC) acknowledges the Post-doctoral research grant (DOCREC20/49) provided by the University of the Basque Country. Other of the authors (AQ) also acknowledges University of the Basque Country by his PhD grant (PIF-15/351). |
URI: | http://hdl.handle.net/10045/123698 |
ISSN: | 2212-9820 (Print) | 2212-9839 (Online) |
DOI: | 10.1016/j.jcou.2022.101888 |
Idioma: | eng |
Tipo: | info:eu-repo/semantics/article |
Derechos: | © 2022 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). |
Revisión científica: | si |
Versión del editor: | https://doi.org/10.1016/j.jcou.2022.101888 |
Aparece en las colecciones: | INV - MCMA - Artículos de Revistas |
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