Abstract
This paper reports the hydrogenation and dehydrogenation of tetralin and naphthalene as model reactions that mimic polyaromatic compounds found in heavy oil. The focus is to explore complex heavy oil upgrading using NiMo/Al2O3 and CoMo/Al2O3 catalysts heated inductively with 3 mm steel balls. The application is to augment and create uniform temperature in the vicinity of the CAtalytic upgrading PRocess In-situ (CAPRI) combined with the Toe-to-Heel Air Injection (THAI) process. The effect of temperature in the range of 210–380 °C and flowrate of 1–3 mL/min were studied at catalyst/steel balls 70% (v/v), pressure 18 bar, and gas flowrate 200 mL/min (H2 or N2). The fixed bed kinetics data were described with a first-order rate equation and an assumed plug flow model. It was found that Ni metal showed higher hydrogenation/dehydrogenation functionality than Co. As the reaction temperature increased from 210 to 300 °C, naphthalene hydrogenation increased, while further temperature increases to 380 °C caused a decrease. The apparent activation energy achieved for naphthalene hydrogenation was 16.3 kJ/mol. The rate of naphthalene hydrogenation was faster than tetralin with the rate constant in the ratio of 1:2.5 (tetralin/naphthalene). It was demonstrated that an inductively heated mixed catalytic bed had a smaller temperature gradient between the catalyst and the surrounding fluid than the conventional heated one. This favored endothermic tetralin dehydrogenation rather than exothermic naphthalene hydrogenation. It was also found that tetralin dehydrogenation produced six times more coke and caused more catalyst pore plugging than naphthalene hydrogenation. Hence, hydrogen addition enhanced the desorption of products from the catalyst surface and reduced coke formation.
Highlights
The possibility of generating thermal energy inside the reactor has been a subject of research in the field of catalysis
Due to the complexity of heavy oil upgrading reactions, upgrading reactions, this study focused on naphthalene and tetralin as model compounds which this study focused on naphthalene and tetralin as model compounds which mimic polyaromatic mimic polyaromatic components in the oil.(HDT)
The hydrogenation and dehydrogenation activity of the catalysts are defined by the extent of
Summary
The possibility of generating thermal energy inside the reactor has been a subject of research in the field of catalysis In this perspective, electromagnetic energy has been converted into heat by a composite catalyst material comprising of a conducting susceptor and a catalytic agent [1,2], or a mixed bed of catalyst and a conducting but chemically inert susceptor [3]. The electromagnetic energy can be supplied through an inductive, ohmic, or microwave system, and the heat generated inside the catalytic bed itself due to the susceptible component to the electromagnetic energy This method of heating the catalytic bed holds several advantages over conventional heating using a furnace as Catalysts 2020, 10, 497; doi:10.3390/catal10050497 www.mdpi.com/journal/catalysts. It is necessary to investigate whether the presence of the electromagnetic field is beneficial to the catalyst performance, mass transport and the chemistry of the reaction
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