The Effect of Sorbitan Monooleate and Alcohol Addition as Flow Properties Improver in Palm Oil Biodiesel

Abstract

The use of the biodiesel B-20 especially in low temperature causes a blockage in the diesel vehicle fuel filter, which in turn causes the vehicle to strike. The blockage is caused by the deposition of monoglycerides (MG) agglomeration. These MG deposits reduce the flow properties of B-20. In this study, the Sorbitan Monooleate (SMO) surfactant was used in palm oil biodiesel (B-100) with 3 variations of alcohol, which are methanol, ethanol, and octanol. For each biodiesel with 0.4% MG content, the concentration of SMO surfactant was varied by 0.1-1% by volume of biodiesel. The molar ratio of surfactant/co-surfactants used is 1:1. Samples of biodiesel were stored at room temperature (±27°C). The effect of SMO and three variations of alcohol was analyzed using two flow properties parameters: Cloud Point (CP), Cold Filter Plugging Point (CFPP), and also supporting data, such as flashpoint and acid number. CP and CFPP were tested every week for a month’s observation. The addition of SMO and octanol to palm oil biodiesel gave the best results by reducing CP by 4.4°C and CFPP by 3°C. The interaction between MG, oleic tails, and hydrogen bonding between them has been analyzed by Fourier-Transform Infrared Spectroscopy (FTIR) method. There are indications of intermolecular hydrogen bonding to MG after the addition of SMO and octanol at wavenumbers 3231.11 and 3289 cm-1.