DOD ASSURED FUELS INITIATIVE: B-52 AIRCRAFT EMISSIONS BURNING A FISCHER-TROPSCH/JP-8 FUEL BLEND

摘要

In support of the DoD Assured Fuels Initiative, the emissions of two TF33 P-103 engines burning JP-8 and a 50/50 blend by volume of JP-8 and Fischer Tropsch (FT) synthetic fuel (referred herein as FT blend) were characterized to determine the impacts of the synthetic fuel on the engine emissions. This effort represents the first emissions evaluation of an actual United States (US) military aircraft operating with a semi- synthetic fuel. The engines were tested on-wing of a parked B-52 aircraft at Edwards AFB, and one of the engines was also tested in Test Cell #8 at Tinker AFB. Gaseous and particulate matter (PM) emissions were quantified. Measurements of the mostly non- volatile PM emissions were performed using conventional instrumentation to determine particle number (concentration), size, mass and smoke number. Soot samples were collected on quartz filters for subsequent chemical analysis. The engines were operated with each fuel at four power settings, idle-to-maximum thrust, and a 50 hour engine endurance test with the FT blend was conducted in the test cell at normal rated thrust. Average reductions of 30-45% in PM mass emissions relative to JP-8 were observed in both engines burning the FT blend. In addition, significant reductions in particle number and engine smoke numbers were also observed. Chemical analysis of the soot samples showed reductions of 50-70% in three and four-ring polycyclic aromatic hydrocarbons (PAH) concentration with the FT blend. Effects of the synthetic fuel on gaseous emissions were negligible except for slight reductions in unburned hydrocarbons and the anticipated reductions in sulfur oxides. In summary, only beneficial impacts on TF33 engine emissions were observed with the use of the FT blend.