The concept developed at HIGFLY for jet fuel synthesis focuses on the use of furfural as main intermediate to yield a variety of hydrocarbons in the jet fuel range. Thus, the main work in RP1 is summarized below:
In WP2, a two-step strategy for the synthesis of furfural (first step) and derivatives (second step) has been investigated. Among the two, the first step constitutes the bottleneck of the entire process and is therefore the primary focus of research. More than 35 solid acid catalyst have been synthesized, characterized and tested, and two promising candidates have identified for further studies. They present competitive product yields, and do not show signs of deactivation. The basis of a kinetic model has been established, and numerical reactor model was built for reactor design purposes. Several methods for coating the new developed materials on 3D structures have been optimized. These new materials have been used for processing of real hemicellulose streams in continuous reactors, with no significant deactivation after 10s of hours of time on stream. These structured catalysts will be use in a HiGee reactor, which has has been designed and is currently being prepared for operation. Tests will start soon. Another key element in HIGFLY is the use of new Deep-Eutectic Solvents (DESs). Among the already reported DESs, a few potential candidates have been identified and tested in the process, showing promising results in combination with the new catalysts developed in the project. Further, a highly advanced AI-based predictive model has been developed for the discovery of new solvents. A completely new solvent with very promising properties is currently being studied.
In WP3, basic catalysts for the condensation of furfural with ketones have been selected and formed structures of these catalysts (pellet or extrudate) have been produced. Two process routes for the condensation of furfural and ketones have been explored: low temperature/liquid phase and high temperature/gas phase. The condensation at low temperature has been translated from batch to continuous using a commercial Al-Mg hydrotalcite, providing 50 h stable operation and high yields of target condensation products. Two of the selected catalysts have been tested under these conditions with diverse product distribution, stability and activity. The condensation process in the gas phase at high temperature has been performed with a commercial basic doped activated carbon catalyst. Besides, an alternative approach for the high temperature process is being explored, where cyclopentanone as produced in WP2 can be used in combination with other biobased alcohols. Furthermore, a variety of Nickel and Platinum Group Metal catalysts were screened for the hydrotreatment of condensed molecules produced from the aforementioned process routes. A few samples of jet fuels were produced, and will be further analyzed in the next period.
The suitability and sustainability of jet fuels derived from furfural and bio-oxygenates is assessed in WP5. The main work of this work package in focused on the following tasks. In the first task, we compiled an inventory of the biorefinery concepts that possibly could be integrated with the HIGFLY process. We analyzed the platform/C5 sugars according to their composition required and derived conclusions on the requirements for the pre-treatment process and the biomass feedstocks. We also looked at the availability of different biomass feedstock options. The second task focused on the conceptual process design, modelling and TEE. Finally, the third task in is a sustainability assessment, which is currently ongoing. In the next period, insights on fuel quality and prospects of regulatory compliance will be further analyzed.
