Fuel Microemulsions for Jet Engine Smoke Reduction

The concept of water and alcohol/fuel microemulsions for the purpose of reducing smoke emissions from jet engine test cells was studied in a T-63 gas turbine combustor. Several ethanol/fuel, methanol/fuel, and water/fuel microemulsions were prepared with JP-4 and JP-8 base fuels and the appropriate surfactants; anhydrous ethanol was miscible in both base fuels. These blends reduced radiation and exhaust smoke, increased CO and total hydrocarbon emissions, and decreased combustion efficiency. NO_x was reduced when the surfactant did not contain nitrogen. The reductions in smoke and radiation correlated with changes in the H/C ratio of the fuel blends. Anhydrous ethanol/fuel solutions were most effective in reducing smoke from the standpoint of cost, operational, and systems effects.