Characteristics of Biojet Fuel

The aviation sector is the largest producer of greenhouse gases, contributing 2% of global emissions. The finite supply of fossil fuels also emphasizes the need for sustainable energy sources in the aviation sector, which are producing significantly lower emissions as well as renewable resources. This chapter discusses the important production routes of biomass-derived fuels, also called biojet fuels (BJFs), which must meet the ASTM International specifications and are clean and complete substitutes for present-day jet fuels. The production of these fuels uses a wide range of biomass; consequently, the fuels produced have very different compositions. The performance characteristics of the fuels based on the physiochemical properties of their constituents are discussed elaborately. It has been observed that there is a direct association between the chemical composition of the biofuels produced and their performance characteristics. Many researchers have suggested that the properties of bio-aviation fuels are appropriate as per the specifications provided by the ASTM standards. The concentration of aromatic carbons is pivotal in influencing the characteristics of fuels. The blends of biofuel with conventional fuels are also studied to improve fuel performance. For biojet fuels to become 100% drop-in fuels in commercial aviation usage, some drawbacks such as the price of production, feedstock availability, energy intensity of the process, and storage stability need to be addressed.