Glycerol Combustion

Abstract

As worldwide production of biodiesel fuel increases, one of the largest concerns is the abundance of waste glycerol. The price of crude glycerol has fallen drastically and many large biodiesel producers are currently paying to landfill this large waste stream. In the search to find a value added alternative, glycerol combustion may be one of the simplest solutions. Heat recovered from glycerol oxidation could easily be used to reduce heating costs inherent to large-scale biodiesel production. It has been stated "Combustion of glycerol would be an elegant solution, if it worked". Clean combustion of glycerol is difficult due to its high viscosity, high auto ignition temperature, and concerns of hazardous emissions. In particular, most in the biodiesel producing community share a fear that burning glycerol could produce acrolein, an aldehyde which is a thermal decomposition product of glycerol and is toxic at very low concentrations. This report will detail the design of a burner that can safely and easily burn crude glycerol for process heating. Emissions testing in the burner using glycerol sources of varying quality confirm that this burner design completely oxidizes the glycerol into CO2 and H2O with very low levels of pollutants, typical of other hydrocarbon fuels. These results show that safe, clean, and efficient combustion of a wide range of glycerol purities is possible with a properly designed burner.