Advancing reaction kinetics of Oxidative Coupling of Methane by operando spatiotemporal reactor analysis

Informations projet

KinGrad-OCM

N° de convention de subvention: 101023416

DOI

10.3030/101023416

Projet clôturé

Date de signature de la CE 25 Mars 2021

Date de début 1 Juin 2021

Date de fin 31 Août 2023

Financé au titre de

• EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions

Coût total

€ 187 572,48

Contribution de l’UE

€ 187 572,48

Coordonné par

TECHNISCHE UNIVERSITEIT DELFT
Netherlands

Periodic Reporting for period 1 - KinGrad-OCM (Advancing reaction kinetics of Oxidative Coupling of Methane by operando spatiotemporal reactor analysis)

Période du rapport: 2021-06-01 au 2023-05-31

Résumé du contexte et des objectifs généraux du projet

Chemical industry is required to be more sustainable and carbon neutral, which depends on the feasibility of new processes/improvement of existing ones. Catalysts, being the heart of most of chemical processes, are pivotal to achieve such a goal. Understanding catalyst performance and reaction kinetics under real operation conditions is vital for the effective design of catalysts. Current methodologies in heterogeneous catalysis for evaluating catalytic performance and extracting kinetic information, assume the chemical reactor to be a magical working black-box without molecular and detailed insights in the reactor. However, reality is more complex, with many physicochemical processes taking place inside the chemical reactor at different time and length scales. Oxidative coupling of methane (OCM), a highly exothermic reaction involving a complex reaction mechanism, is a good example of such complexity. Disentangling the multiple physicochemical phenomena and understanding their contributions to the overall catalytic performance, with the aim to investigate detailed reaction mechanisms and kinetics, constitutes a great challenge. This project has as an overall objective the study of the OCM reaction through the physicochemical gradients at reactor scale (i.e. spatially resolved concentration profiles for reactant and products, temperature profiles in the catalyst bed). To do this, an experimental methodology based on the use of operando spatial reactor analysis techniques was implemented.

Travail effectué depuis le début du projet jusqu’à la fin de la période considérée dans le rapport et principaux résultats atteints jusqu’à présent

Oxidative coupling of methane (OCM) was investigated through an experimental methodology that allows the inspection of the reactor under real working conditions. Thermal phenomena occurring in the catalyst bed were evaluated using a customized reaction system that allows the incorporation of an infrared thermal camera for the catalyst bed temperature inspection under operando (working) conditions. Gas concentration profiles along the catalyst bed were measured by a customized space-resolved gas sampling system that was tailor-made for this application. A particular focus was given to the assessment of OCM reaction kinetics following this methodological approach. A comprehensive kinetic model was developed OCM on MgO catalyst. Kinetics inspection was carried out under non-isothermal conditions, taking into account the concentration and temperature profiles along the catalyst bed. This kinetic model was successfully used to describe OCM in the presence of thermal gradients.
Besides, within this project, the effect of the heating method (i.e. conventional resistive heating and microwave assisted heating) on OCM was also investigated in depth for the advantage of local material heating given by microwave heating for the OCM reaction. Aspects such as the structuration of the catalyst in a core-shell conformation, for the enhanced microwave absorption of the catalyst and the better temperature control in the reactor, aiming to avoid the presence of localized hotspots, was addressed.

Progrès au-delà de l’état des connaissances et impact potentiel prévu (y compris l’impact socio-économique et les conséquences sociétales plus larges du projet jusqu’à présent)

With this project, an experimental methodology that allows the comprehensive evaluation of the performance of a catalytic system under real operation conditions and gain fundamental understanding about the chemical reaction, the catalyst and the reactor thermal behaviour, was set. This methodology is presented as a useful tool not only for those working specifically on oxidative coupling of methane but also for those dealing with elucidating reaction mechanisms and intrinsic kinetics for complex chemical reactions. With this holistic approach a rational design of catalytic systems suitable for a specific reactor configuration is feasible. Furthermore, accurate kinetic models describing the process under more realistic conditions can be developed.
Developing effective catalysts and, thus, making chemical processes more sustainable and efficient are the key aspects to reach European Green Deal objectives. This project looks into chemical processes from a holistic perspective, aiming to gain understanding of them under closer to industry application conditions and rationalize the catalyst design based on experimental observations. More specifically, this project deals with methane activation to useful chemical processes, aiming to reduce oil dependency, providing alternative synthesis routes for key chemicals, such as hydrogen and ethylene. The successful execution of this diversification of chemicals and fuels production relays on efficient use of energy as well. For this aim, microwave-assisted reactors are investigated in this project, which can run under green electricity, in alignment with the REPowerEU goals and the electrification of chemical industry.

Scheme of a) the traditional methodology for the assessment of kinetic studies in OCM and b) the new