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Kinetic Assessment of the Dry Reforming of Methane over a Solid Solution Ni–La Oxide Catalyst

preprint
submitted on 11.03.2021, 16:58 and posted on 16.03.2021, 09:55 by Victor Stivenson Sandoval-Bohorquez, Edgar M. Morales-Valencia, Carlos Omar Castillo-Araiza, Luz Marina Ballesteros Rueda, Víctor Gabriel Baldovino Medrano
The dry reforming of methane is a promising technology for the abatement of CH4 and CO2. Solid solution Ni–La oxide catalysts are characterized by their long–term stability (100h) when tested at full conversion. The kinetics of dry reforming over this type of catalysts has been studied using both power law and Langmuir–Hinshelwood based approaches. However, these studies typically deal with fitting the net CH4 rate hence disregarding competing and parallel surface processes and the different possible configurations of the active surface. In this work, we synthesized a solid solution Ni–La oxide catalyst and tested six Langmuir–Hinshelwood mechanisms considering both single and dual active sites for assessing the kinetics of dry reforming and the competing reverse water gas shift reaction and investigated the performance of the derived kinetic models. In doing this, it was found that: (1) all the net rates were better fitted by a single–site model that considered that the first C–H bond cleavage in methane occurred over a metal−oxygen pair site; (2) this model predicted the existence of a nearly saturated nickel surface with chemisorbed oxygen adatoms derived from the dissociation of CO2; (3) the dissociation of CO2 can either be an inhibitory or an irrelevant step, and it can also modify the apparent activation energy for CH4 activation. These findings contribute to a better understanding of the dry reforming reaction's kinetics and provide a robust kinetic model for the design and scale–up of the process.

Funding

This work was funded by Agencia Nacional de Hidrocarburos –ANH– and Minciencias, Colombia, within the frame of the Project 1102–721–50962: “Desarrollo de alternativas catalíticas para la reducción y valorización de emisiones de gases de efecto invernadero típicas de pozos y refinerías petroleras por combustión catalítica de VOCs y transformación de CO2 y CH4 en gas de síntesis”

History

Email Address of Submitting Author

victor.sandoval@correo.uis.edu.co

Institution

Universidad Industrial de Santander

Country

Colombia

ORCID For Submitting Author

0000-0001-6998-0148

Declaration of Conflict of Interest

No conflicts of interest

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