Upgrading Bio-oil through Emulsification with Biodiesel: Mixture Production

There has been increasing interest in alternative fuels made from biomass, which is abundant and renewable. Bio-oil produced by fast pyrolysis of biomass is highly viscous and acidic and has a high water content. To overcome these problems as a fuel, a method of emulsifying bio-oil with biodiesel has been investigated. In the present study, various effects on the mixture stability have been examined. The optimal conditions for obtaining a stable mixture between bio-oil and biodiesel are with an octanol surfactant dosage of 4% by volume, initial bio-oil/biodiesel ratio of 4:6 by volume, stirring intensity of 1200 rpm, mixing time of 15 min, and emulsifying temperature at 30 °C. Furthermore, selected fuel properties, such as viscosity, density, water content, acid number, and average molecular weight, are measured for characterizing the bio-oil/biodiesel mixture. Thermogravimetric analysis (TGA) has been used to further evaluate the thermal properties. Data from the TGA and Fourier transform infrared (FTIR) analyses confirm the presence or absence of a certain group of chemical compounds in the mixture. The kinetic parameters for the thermal decomposition of the bio-oil, bio-oil/biodiesel-rich phase, and pyrolytic lignin-rich phase were obtained from the TGA experiments.