Development and Evaluation of Alternative Aviation Fuels

There continues to be significant interest in the development, certification, and use of alternative (non-petroleum) aviation fuels. The motivation for this is driven by many factors, including the growing demand and reduced supply of petroleum-derived fuels, cost volatility, and desire for a reliable domestic fuel supply. In addition, the production of alternative fuels from renewable/biological feedstocks can reduce the associated environmental footprint and impact during use. Extensive laboratory and full-scale testing during the past decade have resulted in the approval of synthetic paraffinic-type fuels for use in both commercial and military aircraft. These fuels have been successfully produced from fossil-based resources, plant oils and animal fats, and exhibit favorable operational characteristics, such as excellent high temperature stability and significantly reduced soot emissions. However, currently approved synthetic fuels cannot satisfy all operational needs, requiring blending with petroleum-derived fuels to insure Fit-For-Purpose requirements are satisfied. This constraint reduces beneficial operational aspects of the synthetic fuels and adds a logistical step to the process. As a result, there is continued interest in the identification of optimal feedstocks and processes for the development of Fully Synthetic Jet Fuels (FSJF), which can be used directly as drop-in replacements. An additional goal is that future synthetic fuels will have an environmental footprint which is equivalent to or lower than petroleum-derived fuels.