Combustion characteristics and emissions of Fischer–Tropsch diesel fuels in IC engines

This article gives a condensed overview of Gas-to-Liquid (GTL), Biomass-to-Liquid (BTL) and Coal-to-Liquid (CTL) theory and technology by the use of Fischer–Tropsch (F–T) processes. Variations of the F–T process can be used to tailor the fuel properties to meet end user needs as well as aid vehicle manufacturers in achieving forthcoming emission regulations. They do this by improving engine-out emissions and exhaust gas after-treatment performance. Regardless of feedstock or process, F–T diesel fuels typically have a number of very desirable properties, including a very high cetane number. This review focuses on how fuel properties impact pollutant emissions and draws together data from various studies that have been carried out over the past few years. Reduced emission levels as demonstrated in several publications have been attributed to several chemical and physical characteristics of the F–T diesel fuels including reduced density, ultra-low sulfur levels, low aromatic content and high cetane rating, but not all of them contribute to the same extent to the emissions reduction.