Sustainable Aviation Fuel (SAF) can be made from a variety of renewable sources, such as plant oils, agricultural waste, sugars, and biomass. While SAF is already used in some commercial flights through established production methods like HEFA, Alcohol-to-Jet (ATJ), and Fischer-Tropsch (FT), its broader use is still limited due to high production costs compared to traditional fossil-based jet fuels [3]. In recent years, the Furan-to-Jet (FTJ) route has gained interest for its flexibility in using diverse feedstocks and potential for scale-up. However, like other SAF pathways, it still faces challenges related to energy demand and economic feasibility. To overcome these barriers, process intensification strategies and processes offers a promising solution to reduce energy use, lower costs, and enhance the overall safety and efficiency of SAF production.
This study presents the design and simultaneous optimization of different intensified process alternatives for the aldol condensation stage of FTJ process. This stage is the most critical, as it is where hydrocarbons within the bio-jet fuel range are formed. Additionally, large amounts of water must be separated, which leads to significant energy consumption. The intensified FTJ process uses furfural and acetone as feedstocks, as they are the most common furan and enone, respectively.Among the intensification options explored are thermally coupled distillation, heat integration, reactive distillation, and various combinations of these strategies. at minimizing the total annual cost, Eco-indicator, CO₂ emissions, and individual risk. These metrics are used to evaluate the economic feasibility, environmental impact, and safety performance of the process. This simultaneous design–optimization problem was solved using a Tabu list-enhanced Differential Evolution algorithm, a population-based direct search method specifically designed for discontinuous and highly nonlinear models. As model constraints, the process must meet the jet fuel specifications established in the ASTM D7566 standard.
The results show that the intensification options based on reactive distillation are the most promising, as they show reductions of up to 68% in the Total Annual Cost (TAC) and a 73% decrease in environmental impact according to the Eco-indicator 99, in contrast to the conventional alternative. In terms of safety and emissions, the reactive distillation process shows a 43% improvement in the individual risk index and a 43% reduction in CO₂ emissions compared to the conventional process. Our preliminary findings highlight the importance of process intensification as a key strategy for the sustainability of Sustainable Aviation Fuel (SAF) production. The integration of reactive distillation in the aldol condensation stage not only enables resource optimization and operational cost reduction but also contributes to minimizing environmental impact and improving process safety. In this context, the development and scale-up of intensified technologies such as this represent a significant step toward the energy transition in the aviation sector, aligning with IATA’s emission reduction targets for 2050.
References
[1] U.S. Energy Information Administration. (2024, abril). U.S. energy-related carbon dioxide emissions, 2023. https://www.eia.gov/environment/emissions/carbon/pdf/2023_Emissions_Report.pdf
[2] Xu, N. Li, X. Yang, G. Li, A. Wang, Y. Cong, X. Wang, T. Zhang, Synthesis of Diesel and Jet Fuel Range Alkanes with Furfural and Angelica Lactone, ACS Catal. 7 (2017) 5880–5886. https://doi.org/10.1021/acscatal.7b01992.
[3]Gutiérrez-Antonio, C., Gómez-Castro, F. I., de Lira-Flores, J. A., & Hernández, S. (2017). A review on the production processes of renewable jet fuel. Renewable and Sustainable Energy Reviews, 79, 709-729.