Abstract
As a fossil fuel substitute, bio-jet fuel derived from inedible oilseed crops has the potential to improve energy security, decrease carbon footprint, and promote agricultural economy and social development. The efficient production of bio-jet fuels depends on the identification and characterization of eco-friendly and sustainable feedstocks. Brassica carinata (Arun Braun) cultivars are among the most significant industrial oilseeds that can be utilized as alternative feedstocks in the aviation industry. The study thoroughly evaluated four non-food Brassica carinata cultivars that are indigenous to Ethiopia to determine their suitability as substitute feedstocks for the production of bio-jet fuel. The effects of solvent extraction parameters were studied using response surface methodology with Box-Behnken design in an isothermal batch reactor. Physicochemical characterization, fatty acids profiling, ultimate analysis, analysis of metals and phosphorus concentration, Fourier-transform infrared spectroscopy characterization, and calorific value analyses were performed to characterize the properties of oils. Accordingly, oil yields ranged from 35.93 to 45.25%. Erucic acid (EA) was the most predominant fatty acid in all oils, accounting for 42-50%, of Derash and Yellow Dodolla oils, respectively, making Yellow Dodolla oil a super-high erucic acid oil. In comparison to the other oils, Yellow Dodolla was observed to be the least oxygenated oil, with a 7.80% oxygen content and oxygen to carbon ratio of 0.07, which may enable it to consume a very limited amount of hydrogen gas during hydrodeoxygenation in bio-jet fuel production. It was determined that, except for calcium and phosphorous levels in Tesfa, the concentrations of the metals and phosphorous were very small. Alkanes, alkenes, carboxylic acids, esters, alcohols, aromatics, and olefins were among the most significant and main functional groups identified. Our extraction and characterization results revealed that the Brassica carinata cultivars have very high oil contents, better physicochemical properties, excellent fatty acid profiles, and very low concentrations of heteroatoms (nitrogen, sulfur), metals and phosphorous concentrations, and very low level of oxygen to carbon ratios, making the oils, notably Yellow Dodolla oil, very high quality and promising alternative feedstocks for upgrading of the oils into bio-jet fuels through hydroprocessing pathway.