The thesis aims to maximize CO2 conversion yields towards Sustainable Aviation Fuels (SAF, C8–C16). Currently, direct CO2 hydrogenation over an iron-based catalyst predominantly produces short-chain olefins (C2–C4), which do not meet SAF specifications. The proposed approach is to combine an iron-based catalyst with a zeolite catalyst within a single reactor, thereby integrating olefin production via CO2 hydrogenation with their subsequent conversion into longer-chain hydrocarbons in the SAF range (C8–C16). The zeolites investigated will exhibit properties tailored to this objective while retaining conventional formulations compatible with process scale-up.
The objective of the thesis is to understand how the formation of long-chain hydrocarbons suitable for the SAF fraction can be promoted by combining iron-based and zeolite catalysts within a single reactor. Two research areas will be investigated to achieve this objective. The first will focus on short olefin oligomerization (ethylene, propylene, butylene), assessing the influence of operating conditions and the presence of by-products from CO2 hydrogenation on the distribution of the resulting hydrocarbons. The second will investigate the integrated CO2 hydrogenation and olefin oligomerization process, aiming to understand the interactions between the two reactions and identify operating conditions that maximize selectivity and yield towards SAF-range hydrocarbons. Particular attention will be paid to the effects of thermal gradients and heat transfer phenomena on catalytic performance, product distribution, and catalyst stability.