Combination of oscillatory and hydrodynamic system for biodiesel production from sunflower oil

In recent years, biodiesel as renewable energy has attracted much attention. The major aims of the biodiesel production method are high conversion and reduced reaction time. This study aimed to optimize biodiesel production from sunflower oil using the transesterification method in oscillatory-hydrodynamic combined systems. The dimensions of the smooth periodic constriction reactor (SPC), tube diameter (D), the diameter of constricted area (d(0)), and baffle spacing (I) were obtained at 5, 2, and 13mm, respectively. The process optimization was carried out by response surface methodology. The results indicated that by increasing residence time from 30s to 90s, the yield was increased about 6%. By increasing the catalyst concentration from 0.75% to 1%, the yield increased approximately 6%; increasing the molar ratio from 6:1 to 9:1 increases the yield. The yield was also increased with the reaction temperature rise from 30 degrees C to 40"C. Then, by increasing the temperature from 40 degrees C to 50 degrees C, the methyl ester content was increased from 81.59% to 85.75%. The optimum point was tested and compared with the ASTM D6751 standard. The results showed that transesterification of sunflower oil with this combined system could function as a good alternative to diesel.