The Formation Of Rhamnolipid-Based Water-Containing Castor Oil/Diesel Microemulsion And Performance Study

Vegetable oils are a kind of natural renewable liquid fuel. They have been recognized as one of the most potential and the ideal alternative energy of oil in the world. But vegetable oils have undesired properties such as high viscosity, low heating value, high ignition temperature, high corrosiveness and high carbon residue content, etc. Therefore, they can't be directly applied to the existing diesel engine. Solubilizing Vegetable oils into diesel by microemulsion technology is one of the most convenient approaches for further upgrading vegetable oils.The microemulsion technique of vegetable oils has the advantages of viscosity reduction and environment-friendly properties. In this study, the phase behavior of the microemulsion and the solubilization mechanism of water and castor oil in diesel were researched to evaluate the solubilization capacity of water and castor oil in diesel under given conditions. The effects of several microemulsion parameters on the solubilization capacity of water and c astor oil in diesel microemulsion were evaluated. The proper concentration of rhamnolipid(RL) was 50 g/L. N-octanol was certified as an ideal co-surfactant with the optimal co-surfactant/surfactant(C/S) mass ratio(w/w) of 0.60. The optimum castor oil/diesel(V/D) volume ratio(v/v) was 0.18.Meanwhile, the fuel properties of water-containing castor oil/diesel(WCD) microemulsions were examined, including the viscosity, water content, density, heating value, cloud point, pour point, corrosivity and elemental analysis. And the thermal and storage stability of WCD microemulsion were also conducted. Compared to the original castor oil, the WCD microemulsion presented more desirable fuel properties. But it still had some unsatisfactory features, such as heating value and stability. While the WCD microemulsion has improvement in fuel efficiency and exhaust emissions of pollutants.In sum, the processing of microemulsion technique may be a promising method to apply vegetable oils for use as an additive to diesel. WCD microemulsion as fuel alternatives, has very good application prospects and practical value.