Catalytic hydrogenation reaction micro-kinetic model for dibenzyltoluene as liquid organic hydrogen carrier

• Published in: Applied energy 2024-07, Vol.365, p.123262, Article 123262
• Main Authors: Tomić, Aleksandra, Pomeroy, Brett, Todić, Branislav, Likozar, Blaž, Nikačević, Nikola
• Format: Article
• Language: English
• Subjects: Dibenzyltoluene; Hydrogenation; Langmuir-Hinshelwood kinetics; Liquid organic hydrogen carrier; Reaction kinetics modeling
• ISSN: 0306-2619
• DOI: 10.1016/j.apenergy.2024.123262

The implementation of the liquid organic hydrogen carrier (LOHC) technology for efficient energy storage requires the development of a reliable kinetic model for both hydrogenation and dehydrogenation processes. In this research study, the catalytic hydrocarbon saturation for a dibenzyltoluene (DBT) mixture solution, containing dibenzylbenzene (DBB), dibenzylethylbenzene (DBEB) and impurities has been performed in the presence of Ru/Al2O3 particles. The influence of different reaction conditions, such as temperature, pressure, initial reactant concentration, catalyst amount and stirring speed has been examined. A measurement-based system micro-kinetics, based on the Langmuir–Hinshelwood mechanism with dissociative H2 surface adsorption, has been derived. H2 thermodynamic solubility equilibrium was defined through Henry's law. The adsorbing, desorption and reactivity of inert solvent molecules was not considered to be relevant. The mass transfer resistance over 1000 rpm stirring speed was negligible. Relative- and mean squared error of representation were 40.9% and 1.00×10−4, respectively. Expressions gave an excellent data prediction for the profile period trends with a relatively accurate estimation of H2 intermediates' rate selectivity, H2-covered area approximation and pathway rate-determining steps. Due to the lack of commercially available standard chemical compounds for quantitative analysis techniques, a novel experiment-based numerical calibration method was developed. Mean field (micro)kinetics represent an advancement in the mesoscale mechanistic understanding of physical interface phenomena. This also enables catalysis structure–activity relationships, unlocking the methodology for new LOHC reaching beyond traditional, such as ammonia, methanol and formate, which do not release H2 alone. Integrated multiscale simulations could include fluidics later on. [Display omitted] •Experimental hydrogenation of DBT-based LOHC mixture over Ru/Al2O3 particles.•Influence of temperature, pressure, stirring, initial LOHC and catalyst amount.•Micro-kinetic model with Langmuir-Hinshelwood mechanism and dissociative adsorption.•Parameter estimation using genetic algorithm and Levenberg–Marquardt algorithm.•Excellent concentration profile trends and parameter influence predictions.