Investigation of the utilization of mint oil (Mentha sp) as an antioxidant in biodiesel-diesel fuel blends

The aim of this thesis is to examine the antioxidant activity of peppermint oil on the oxidative stability of biodiesel fuel and diesel fuel mixtures produced from different sources. Additionally, this study is a comparative study that reveals the critical importance of the role of antioxidants in preventing and delaying the aging process of biodiesel. This thesis study proposes improvements for the oxidation problem that may arise in the use of biodiesel, which is among the renewable energy sources, with diesel fuels. For this purpose, biodiesel-diesel mixtures (B100, B20D80, D100) were prepared in certain proportions. In order to increase the oxidation stability (degradation times) of these mixtures, the usability of mint extracts as natural and economical antioxidants as an alternative to synthetic and expensive antioxidant types available in the market was examined. Prepared peppermint extract-added biodiesel-diesel fuel mixtures were evaluated with Fourier Transform Infrared Spectrophotometry (FT-IR), Ultraviolet Visible Spectroscopy (UV-Vis)Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) characterization techniques. Additionally, to evaluate the combustion performances of fuel mixtures, engine tests were performed in which fuel consumption data, torque and power status, exhaust temperature, brake thermal efficiency, CO, NO, and smoke opacity change were analyzed.