EFFECT OF ADDITIVES ON THE CLOUD POINT OF PEANUT BIODIESEL FUEL AND THERMOGRAVIMETRIC ANALYSIS ON BIODIESEL COMPONENTS

摘要

The properties of the bio-oil make up the composition of the biodiesel and determine the fuel properties. The main acids of bio-oil are stearic, palmitic, and oleic acid. The properties of these acids influence fuel properties such as cloud point, viscosity, and emissions. By studying the properties of these acid components as well as their methyl esters, it will be able to be determined what chemical properties of these acids influence the fuel properties of biodiesel. For this project, the research group focused on how the addition of an additive, diesel, affected the cloud point of peanut biodiesel. Thermogravimetric analysis was conducted to characterize the thermal stability of the main acids of peanut bio-oil and the five main methyl esters of peanut biodiesel. Thermogravimetric analysis, TGA, uses heat to force reactions and physical changes in the material. It provided measurements of the mass change in the components of biodiesel when it is heated. At 150℃, stearic acid had the most significant weight loss when compared to oleic and palmitic acid. Methyl stearate had the most significant weight loss at 140℃ when compared to palmitate, oleate, linoleate, and linolenate methyl esters. Cloud point is the temperature at which a cloud of wax crystals first appear in a liquid when it is cooled. Cloud point is used to determine the lowest temperature at which the biodiesel can be used in an engine. Previously, researchers have found that higher saturation in oils tends to lead to biodiesel fuels with higher cloud points. Saturated fatty acids freeze and melt at higher temperatures than unsaturated fatty acids. Biodiesel fuels with saturated FAMEs have higher cloud points while fuels that consist mostly of unsaturated FAMEs have very low cloud points. This conclusion was drawn by comparing the cloud point analysis of peanut biodiesel and palm biodiesel. Upon the completion of the cloud point analysis, it was determined that the cloud points of the peanut and diesel fuel were 17.28℃, and 3.2℃, respectively. It can be concluded that peanut biodiesel is not a suitable biodiesel for cold weather climates without an addition of an additive.