The Formation of Rhamnolipid-Based Water-Containing Castor Oil/Diesel Microemulsions and Their Potentiality as Green Fuels

Abstract

The utilization of vegetable oils as a source of renewable fuels has attracted much attention. However, the high viscosity of vegetable oils limits their long-term application. 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 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. Moreover, fuel properties of water-containing castor oil/diesel (WCD) microemulsion were identified, including density, dynamic viscosity, cloud point, pour point, water content, corrosivity, heating value, and elemental composition. The thermal and storage stability of WCD microemulsion were also conducted. Compared with castor oil, WCD microemulsion has lower viscosity, which presents similar fuel characteristics as diesel.

Rhamnolipid based glycerol-in-diesel microemulsion fuel: Formation and characterization

“…Thus, the optimum RL dosage was determined to be 0.05 g mL À1 , which is agree with the result reported in Ref. [18].…”

“…Biosurfactant has the advantages of high efficiency, biodegradability, and sustainability compared to synthetic surfactant [16]. Note that biosurfactant rhamnolipid (RL) has been proven to have good performance on microemulsion fuel formation [17,18]. In this study, RL was applied to obtain good performance on glycerol microemulsification.…”

Formulation of an economical microemulsion of diesel/colza oil fuel and investigation of some physical parameters for its stability

“…Under the constant stirring at 1000 rpm the mixture was titrated with co‐surfactant to obtain a single phase microemulsion. Ternary diagram phase showing the phase behavior of this system was constructed . …”

“…Under the constant stirring at 1000 rpm the mixture was titrated with co-surfactant to obtain a single phase microemulsion. Ternary diagram phase showing the phase behavior of this system was constructed [35,36].…”

The comparison of oxidative thermokinetics between emulsion and microemulsion diesel fuel

“…Water fuel emulsion and microemulsion can not only improve the properties of the base fuel, but they can also be further used to upgrade bio-oil [4][5][6], glycerol [7][8][9], and vegetable oil [10,11], etc. The emulsion and microemulsion fuel systems had the advantages, in comparison to the base fuel, of saving energy, enhancing engine torque, improving engine performance, and reducing the emissions of particulate matter (PM), CO, NO x , and persistent organic pollutants [8,[12][13][14].…”