Periodic Reporting for period 3 - BioSFerA (BIOfuels production from Syngas FERmentation for Aviation and maritime use)
Período documentado: 2022-10-01 hasta 2024-03-31
The widespread use of petroleum-derived jet fuels has significantly depleted petroleum reserves while contributing substantially to greenhouse gas (GHG) emissions, making the airline sector responsible for 3% of total GHG emissions. Similarly, international shipping accounted for 2.2% of global anthropogenic CO2 emissions in 2012. The Paris Agreement's targets have placed both sectors under increasing environmental scrutiny, driving demand for sustainable alternatives. Biofuels have emerged as a promising solution for reducing CO2 emissions in aviation and shipping. However, challenges such as the food vs. fuel debate, high feedstock costs, and uncertainty over cost reductions in current biofuel production necessitate alternative approaches to make drop-in biofuels more competitive. The BioSFerA concept refers to a combined thermochemical-biochemical Biomass-to-Liquid (BtL) pathway for the production of aviation and maritime liquid fuels valorizing a wide range of non-food bio-based feedstock to produce drop-in biofuels. BioSFerA develops and validates a novel biorefinery concept based on a 2-step biological gas-to-liquid process using syngas from a Dual Fluidized Bed Gasifier (DFBG) targeting the production of hydrotreated triacylglycerides (HTAGs) for next-generation aviation and marine biofuels. The concept offers multiple advantages, including feedstock flexibility, lower capital costs due to minimal gas cleaning requirements—since the bacteria involved can tolerate relatively high levels of contaminants—mild operating conditions with moderate temperatures and pressures, and enhanced lipid production, as strain engineering efforts have successfully increased yeast lipid content during liquid fermentation. Scale-up studies indicated that BioSFerA is fully competitive with the established BtL technologies, such as Fischer-Tropsch (FT) and Alcohol-to-Jet (AtJ) in terms of performance. In addition, the techno-economic analysis indicated that BioSFerA could also be economically competitive, with an estimated minimum selling price of 1.83 €/L for jet fuel—comparable to the leading BtL technologies—and 1.71€/L for marine fuel. Business analyses across Europe confirmed that BioSFerA-based value chains are both cost-effective and investment-friendly. Finally, the technology can achieve GHG emission savings of up to 86%, demonstrating a significant environmental benefit.
Within BioSFerA, the technologies comprising the overall biomass-to-liquid (BtL) process chain, i.e. biomass gasification and gas cleaning, syngas conversion to microbial oil via two-step fermentation, and lipid hydroprocessing, were initially tested and optimized at a small scale (TRL 3) and subsequently developed and validated at pilot scale (TRL 5). Six different types of biogenic residues and wastes were gasified, and the resulting syngas streams were confirmed to be suitable for gas fermentation, as the bacterial strains used for acetate production demonstrated resistance to syngas contaminants. As a result, fewer gas cleaning steps are required compared to thermocatalytic pathways such as Fischer-Tropsch synthesis. The successful integration and piloting of the gasification and gas fermentation units were accomplished, achieving an acetate production rate of up to 0.77 g/L/h. Three different substrates (acetate, glucose, and glycerol) were tested for lipid production, with rates reaching up to 0.261 g/L/h. It was validated that no intermediate acetate purification is required prior to liquid fermentation, enabling the direct transfer of the first broth to the second reactor. Steam explosion was identified as an efficient method for lipid extraction, contributing to the energy and capital requirements at the downstream processing section. Hydroprocessing tests resulted in the production of 1 barrel of jet fuel and 1 barrel of marine diesel fuel. The diesel fraction can be considered a high-quality bunker fuel or used as an additive to enhance commercial marine diesel. Most of the measured properties of the jet fuel fraction comply with Jet A-1 specifications, except for the freezing point. Process simulations indicated an energy efficiency of 35.6% of the entire system at industrial scale and a total carbon utilization of 25.4% for advanced biofuels production. As part of the techno-economic analysis conducted within the project, the minimum selling price of jet fuel was estimated at 1.83 €/L, highlighting the cost-effectiveness and competitiveness of the BioSFerA concept. Additionally, a life cycle analysis demonstrated the lowest carbon footprint among all cases examined, at 15.5 g CO2eq/MJ, with estimated GHG emission savings ranging from 48% to 86% compared to conventional fossil fuels. Overall, the results achieved during the project were disseminated through 28 events, including conferences and exhibitions. Key outcomes have been detailed in 8 peer-reviewed scientific publications.
Within BioSFerA project, a new process pathway was developed for the production of advanced biofuels from biogenic residues and wastes, combining thermochemical (gasification), biotechnological (fermentation) and thermocatalytic (hydroprocessing) technologies. For the first time, a biomass gasification unit was connected with a gas fermentation unit and operated at pilot scale for the production of acetate, serving as an intermediate for advanced biofuels for aviation and maritime. Different feedstocks were successfully utilized, demonstrating the system’s flexibility. As the fermentation process is less sensitive to contaminants than conventional chemical synthesis methods, a simplified gas cleaning approach with minimal syngas treatment is sufficient, significantly reducing both capital and operational costs. Lipid extraction posed another challenge, as steam explosion was applied for the first time to disrupt the cell walls of oleaginous yeast. The resulting biofuels, produced through hydrotreatment of the purified triacylglycerides, can serve as drop-in fuels for hard-to-abate sectors such as aviation and maritime, thereby contributing to the decarbonization of transport. From an environmental perspective, CO2 emissions are expected to be very low—or even negative—if the CO2 stream generated during fermentation is effectively utilized. In terms of societal impact, BioSFerA will supply the aviation and maritime sectors with sustainable, clean biofuels, supporting their emission reduction targets and ultimately enhancing public health. The industrial-scale development and market uptake of the BioSFerA concept will generate new employment opportunities and stimulate economic growth. Its innovative and efficient approach to liquid biofuel production is expected to strengthen the EU's leadership in renewable fuels for aviation and maritime sectors, while enhancing its competitiveness within the rigorous framework of the Paris Agreement. Finally, the use of biogenic residues and agroindustrial or forestry wastes as feedstock ensures no negative impact on food availability or prices, while simultaneously supporting economic growth in rural areas.