(496a) Production of Biodiesel Fuel From Tall Oil Fatty Acids

Tall oil fatty acids are a bi-product of the paper industry consisting of almost 100% free-fatty acids. Although this feedstock is ideal for biodiesel production, there has been relatively little study on its conversion to biodiesel. Thus, the purpose of this study was to investigate the high temperature reaction of methanol with tall oil at subcritical and supercritical pressures to produce fatty acid methyl esters. This work successfully reacted tall oil fatty acids with supercritical and subcritical methanol in a continuous tubular reactor, resulting in a temperature controlled reaction. Conversions at subcritical pressures of 4.2 MPa and 6.6 MPa were 87 percent and 89 percent, respectively. Pressure seemed to have very little correlation to conversion in both regimes, and conversions were comparable between the two. Additionally, it was also found that tall oil fatty acids react well with methanol to give comparable conversions at the relatively low molecular flow ratio of less than 10 in methanol. Both of these observations suggest that hydrolyzed triglycerides or free fatty acid feedstocks would make the primary biodiesel reaction and the subsequent separation and purification significantly less expensive to operate.