By Lars Raakilde Jespersen, AAU Energy

Assistant Professor Daniele Castello from the Advanced Biofuels Research group at AAU Energy will concentrate on the final improvement of preprocessed biomass material into jet fuel, kerosene. Project Circulair is a consortium of ten partners from six countries with a strong representation from Denmark. Aarhus University, Circlia Nordic, Topsoe and Aalborg University participate together with companies and universities from Sweden, Germany, Italy, Spain and France.

Straw and manure from farming are used as feedstocks because they are abundant waste products. They are preprocessed into an oily, energy-dense black liquid named “biocrude” thanks to a novel process called hydrothermal liquefaction (HTL). This is where Castello’s team takes over and applies hydrotreating, a process involving pressurized hydrogen and a catalyst.

This process improves the biocrude and refines it into usable fuel by removing elements such as oxygen and nitrogen, which should not be in fuel. Afterwards they have the very same chemical product as ordinary kerosene.

That is not easy. There are a lot of requirements for fuel to be used in commercial aviation jets. As an example, it must not freeze even at temperatures as low as -47 ºC. Furthermore, jet fuel must be exceptionally clean, not leaving residues, when burned in the engine. And overall yields must be high for the process to be economically attractive.

Daniele Castello and the team at AAU Energy will build on solid expertise developed during several other national and European projects, counting on an extensive knowledge and a unique infrastructure, including continuous lab-scale setups and advanced analytical capacities.