50/50 JP5/ATJ5 Specification and Fit-for-Purpose Test Results

This test report summarizes specification and fit-for-purpose (FFP) test results of a 50/50 blend of petroleum JP-5 and two alternative fuel blend stocks produced via the alcohol-to-jet synthetic paraffinic kerosene (ATJ-SPK) process (herein referred to as 50/50 JP5/ATJ5). ATJ-SPK was made by converting a biomass to an alcohol intermediary to a hydrocarbon that meets military specification. The end product of the ATJ SPK process is very similar in chemistry to previously qualified aviation alternative fuel blend stocks, such as Hydroprocessed Esters and Fatty Acids (HEFA) and Fischer Tropsch (FT). Two distinct batches of ATJ fuels were evaluated. These two batches were produced from two different types of butanol intermediaries, but showed overall similar chemistry and physical properties. One of the 50/50 JP5/ATJ5 blends passed all FFP requirements set forth by in the Navy Standard Work practice 44FL-006 (Naval Fuels and Lubricants CFT Shipboard Aviation Fuel, JP-5). The second 50/50 JP5/ATJ5 blend had a derived cetane number outside the range of petroleum JP-5. Cetane only affects diesel engines and mitigations for low cetane fuels in diesel engine applications are being considered. Viscosity at -20 deg C of the blends met the JP-5 specification; however these values fall near the upper end of the normal range operating experience. Additional investigation is being done to assess any potential risk of operating with viscosity in this regime. When both ATJ fuels are blended with petroleum JP-5, the properties of the two blends are very similar to one another. These test results support the continued qualification of 50/50 JP5/ATJ5 for use by the U.S. Navy and provide documentation to support the approval of all butanol based-ATJ blends under one qualification process. The original document contains color images.