(768b) Visualization Studies of the Evaporation and Combustion of Alternative Liquid Fuels At Elevated Temperatures

A number of liquids offer potential as alternative energy sources for high temperature energy conversion. Glycerin and certain waste oils were chosen as liquid fuels for this study to determine their viability as supplements for the energy needs of a cement plant.  Visualization studies were carried out in a laboratory scale drop tube furnace system and an infrared heater to analyze the behavior, degradation, and combustion of these alternative liquid fuels. Techniques using high speed cameras and high magnification lenses are discussed for studies with suspended and free-falling droplets in the environments where the temperature and the gas composition are precisely controlled. Suspended droplets studies were conducted using micron sized graphite capillary tubes and thin wire thermocouples. Free-falling micron-sized droplets were generated using a custom piezoelectric drop-on-demand generator. High resolution visualization images and video showing the interaction of alternative liquid fuel droplets at elevated temperatures are presented. Results are used to estimates rates and mechanisms for evaporation and combustion of the liquids at specified gas atmospheres and high temperatures, particularly those that simulate energy generation in cement production.  The goal is to use the results to evaluate co-firing options for coal and other traditional fossil fuels.