Production of Biojet Fuel

The worldwide aviation industry emits almost 920 Mt. of CO2, which is 2.5% of the global anthropogenic CO2 emissions and 12% of the emissions from the transport sector. The aircraft also emits other gases that can cause changes in the atmosphere, such as nitrogen oxides (NOx), water vapor, and soot. Considering the emission of CO2 and non-CO2 (NOx, water vapor), the aviation sector is responsible for about 5% of the total global warming effect caused by humans. Because of the environmental impacts and the problems linked to the fossil fuel (price, availability, national security), it is necessary to reduce the fuel consumption and carbon footprint of the aviation industry. One possibility to achieve these aims is to use a sustainable aviation fuel based on biological source, the biojet fuels. The biojet fuel can be produced using a variety of processes, such as hydroprocessing of triglyceride feedstock, thermochemical processing of biomass, and alcohol-to-jet, direct sugar-to-hydrocarbon, and aqueous-phase reforming. Each one of these pathways has some advantages and disadvantages, and its technology readiness level is discussed in this chapter.