Book Description

The development of alternative liquid fuels has shifted from fuels such as ethanol and biodiesel, which are often created from food sources, to more advanced feedstocks, such as Algae, and synthetic fuels, such as Fischer-Tropsch diesel and other "renewable" fuels. This study was designed to characterize the physical combustion performance of ethanol, biodiesel, and an algae-derived "Hydrotreated Renewable Diesel." The physical properties of the fuels were characterized in order to describe the atomization behavior. In addition, Gas Chromatography/Mass Spectrometry provided insight into the chemical composition of each fuel. A swirl-stabilized research combustor was used to conduct experiments to simulate gas turbine combustion, and emissions and lean stability limits were measured. At cold-flow conditions, ensemble laser diffraction provided measurements of atomization characteristics, and high-speed cinematography provided additional insight. Most of the fuels had similar atomization characteristics, despite having a wide range of physical properties, which is attributed to the atomization strategy used in this work. However, biodiesel did exhibit larger droplets (5 microns larger on average), indicating that viscosity does have some effect on prompt atomization. Due to the nature of its production, the Hydrotreated Renewable Diesel performed similar to the conventional petroleum fuels, suggesting a high degree of interchangeability with conventional fuels. Ethanol, with the highest oxygen content, and the lowest heating value produced the lowest NOx emissions. Among the fuels examined, differences in emissions were attributed to differences in the evaporation and chemical behavior; with alternative fuels showing benefit over the conventional fuel.