Biodiesel production using supercritical methyl acetate in a tubular packed bed reactor

This work investigates the biodiesel production with supercritical methyl acetate in a tubular packed bed reactor. The influence of temperature, oil to methyl acetate mass ratio and reaction time was evaluated throughout experiments performed at pressure of 20 MPa. The temperature ranged between 300 and 400 °C, and the oil to methyl acetate mass ratio varied between 1:2 and 1:5. Two different oils with very different composition and free fatty acid content were utilized: soybean oil and macauba oil. According to the results obtained, 44% was the highest ester yield obtained for soybean oil at 350 °C, 45 min of reaction time and oil to methyl acetate mass ratio of 1:5. In this condition a decomposition of 48% was also achieved. For the macauba oil, the highest ester yield was 83% with a decomposition of 17%, achieved at 325 °C, oil to methyl acetate mass ratio of 1:5 and 45 min of reaction time. A comparison between the oils allows pointing out that macauba oil presented better performance, probably due to its high free fatty acid content.

► Transesterification with methyl acetate were conducted in a packed bed reactor. ► Two raw materials with different composition were utilized: soybean and macauba oils. ► Ester yields and degradation degree were determined in different reaction conditions. ► Macauba oil presented higher yield and lower decomposition compared to soybean oil. ► The better results of macauba oil can be due to its high free fatty acid content.