Advanced Fuel Development and Fuel Combustion. Delivery Order 0005: Mitigation of Particulates Using Fuel Additives

摘要

The overall technical objective of the program was to develop an additive for JP-8, JP-5, and diesel fuels that will reduce both the mass Emissions Index (grams of PM2.5 emissions/kilogram of fuel) and the number density Emissions Index (particle number density of PM2.5 emissions/kilogram of fuel) in the exhaust of military gas turbine engines by 70 percent. This report summarizes the results of work performed at United Technologies Research Center. Baseline studies were performed with ethanol added to ethylene, as the method and procedures could be validated against the existing experimental database. Experiments were performed in laminar premixed burner-stabilized flat flames. Soot was reduced by factors of about 50% with ethanol. Subsequent tests were performed with mixtures of heptane/toluene/ethylene to provide a better simulation of real fuel chemistry. The most significant effects were observed with a proprietary additive which apparently contains a metal. The use of metals is not perceived to be an environmentally acceptable approach. The next most effective additive is a commercial fuel additive, Kleen, which contains a variety of oxygenated (nitro) compounds. Reductions of soot emissions on the order of 30% were observed. Mixed results were obtained with pyridine, and modeling results show negligible influence of this additive. Finally, advances to a fundamental soot formation model were accomplished by comparing simulations of coflow diffusion flames to experimental data sets. This work resulted in proposed changes to the gas-phase kinetics and soot inception models and identifying the importance of treating soot ageing and radiation losses. The overall goal of identifying an additive that can reduce soot emissions by 70% was not achieved, without use of a metal-containing additive or with very high levels of the additive (>10% by weight).