Effect of monopalmitic content and temperature on precipitation rate in biodiesel-petroleum diesel blends

Abstract

The need for cleaner fuel increases alongside the necessity of reducing greenhouse gas emissions. Biodiesel is considered as one of best options for cleaner energy. However, it has disadvantages due to lower stability, lesser cold flow properties (CFP), and higher viscosity, which are mainly caused by fatty acid type and content. These works investigate CFP of various biodiesel blends B20 & B30, with the objective on how the monopalmytic as one of the saturated monoglycerides (SMG) content and Temperatures affect the precipitation rate. A set of 100ml separatory funnels containing various samples were put in refrigerators in controlled-temperature, i.e.15°C; 20°C; and room temperature. The rate of precipitation was observed every day for 2 weeks using 0.8μm membrane filter. Results indicated precipitation rate of B30 was higher than that of B20. As it was expected, the precipitate was taken at the same temperature, 20°C, resulting in B30 had more precipitate in the end (37.6 mg) compared to B20 (22.2 mg). The closer to cloud point also indicates the higher rate of precipitation as 4th day B20 at 15°C (25.4 mg) compared 4th day B20 at 20°C (19.3 mg). The change of crystal from less stable α-phase to more stable, less soluble β-phase is also proven to significantly affect the rate of precipitation.