Prescreening Guidance for Alternative Jet Fuels
The aviation industry’s evaluation and qualification process for synthesized jet fuel components, as detailed in ASTM D4054 and elsewhere, can involve four tiers of testing, two research reports, and three balloting junctions. This process can be resource-intensive, but ensures that any alternative fuel specification approved by the industry outlines the production of safe, fungible Alternative Jet Fuel (AJF) that is compliant with stakeholder demands arising from their insights into the need for such physical and fit-for-use properties. However, this process can span multiple years at significant cost to all parties involved, making mid-course fuel qualification corrections painful to prospective AJF developers. The extensiveness of this process has highlighted a need for early-stage, low volume, low cost, and rapid prescreening techniques outside the formal ASTM D4054 approval and evaluation process, especially those that relate to the assessment of jet engine combustor operability, which are among the most expensive testing requirements of the evaluation process. The Prescreening of Synthesized Hydrocarbons Intended for Candidates as Blending Components for Aviation Turbine Fuels document identifies prescreening methods that can provide early stage confidence to fuel developers on whether AJF formulations might encounter downstream challenges with the completion of the ASTM D4054 evaluation process.
These prescreening methods have been developed from learning acquired from the National Jet Fuels Combustion Program (NJFCP), JETSCREEN, prior industry approvals of AJF, and other associated AJF programs. These methods do not replace the ASTM D4054 evaluation process and its requirements. However, results from this prescreening should provide an early assessment of whether serious combustion issues could be encountered in the formal approval process. This could help AJF developers make early decisions on AJF composition or production processes that could help facilitate later approval, either for Fast-Track or Standard approvals (see ASTM D4054 Standard Practice).