Sustainable aviation fuels (SAFs), produced from waste and renewable sources, are a promising means for reducing net greenhouse gas emissions from air travel while still maintaining the quality of air transportation expected. In this work, the catalytic co-pyrolysis of polystyrene and pine with red mud (bauxite residue) and ZSM-5 catalysts at temperatures of 450 °C, 500 °C, and 550 °C was investigated as a method for producing aromatic hydrocarbons with carbon numbers ranging from 7 to 17 for use as additives to blend with SAF produced through other methods to add the required quantity of aromatic molecules to these blends. The maximum yield of kerosene-range aromatic hydrocarbons was 620 mg per gram of feedstock (62% of feedstock was converted to kerosene-range hydrocarbons) obtained at 550 °C in the presence of ZSM-5. Additionally, it was noted that a positive synergy exists between pine and polystyrene feedstocks during co-pyrolysis that cracks solid and liquid products into gaseous products similarly to that of a catalyst. The co-pyrolysis of pine and polystyrene without a catalyst produced on average 17% or 36.3 mg more kerosene-range hydrocarbons than predicted, with a maximum yield of 266 mg of C7–C17 aromatic hydrocarbons per gram of feedstock (26.6% conversion of initial feedstock) obtained at 550 °C.

The conversion of biomass into bio-oil through the pyrolysis process offers numerous benefits, such as bio-fuel and bio-resin synthesis. However, for bio-oil usage for any application, understanding its composition is vital. Therefore, this study investigated the effects of different commonly available woody biomass (Douglas fir, eucalyptus, and poplar) on bio-oil composition. The bio-oil was produced through fast pyrolysis at 500 °C in a fluidized bed reactor and collected using an electrostatic precipitator. The chemical composition was analyzed using gas chromatography–mass spectroscopy, and the hydroxyl groups were quantified using phosphorous-31 nuclear magnetic resonance. The poplar bio-oil had the most significant proportion (67 area%) of lignin-derived compounds and the highest OH concentration (6 mmol g⁻¹). However, the proportion of carbohydrate-derived compounds was the largest (44 area %) in bio-oil produced from Douglas fir. Based on the OH concentration, poplar would be the most suitable feedstock for resin synthesis among the three feedstocks tested.