The Influence of Sorbitan Monooleate as a Surfactant and Octanol as a Co-surfactant to Restore Biodiesel’s Flow Properties at the Cold Temperatures

Abstract

The application of the biodiesel-diesel mixed fuel at the cold temperatures causes problem stoppage in the diesel engine. This is caused by the precipitation of agglomerate Saturated Monoglycerides (SMG). From the previous study, the addition of 1% Sorbitan Monooleate (SMO) could reduce the Cloud Point (CP) and Cold Filter Plugging Point (CFPP) respectively by 4.2°C and 2°C. In this study, SMO was used as a surfactant with octanol as a co-surfactant. For each biodiesel with 0.4-0.6% MG, the SMO was varied by 0.1-1% v/v. The molar ratio of the SMO/octanol is 1:1. Samples of biodiesel were stored at the cold temperatures (±16°C). The effect of addition SMO and octanol was analyzed by Differential Scanning Calorimetry (DSC) and the changes of MG’s droplet particle size were analyzed by Particle Size Analyzer (PSA). As the results, the addition of SMO and octanol reduced CP by 4.6°C and CFPP by 3°C. The PSA and DSC method proved that there were changes in MG’s particle diameter and onset temperature respectively from 8.18-68.30 µm to 0.29-8.88 µm and from 9.79°C to 4.97°C. The changes indicate that the SMO and octanol have roles in reducing the agglomeration of MG in biodiesel.