Transesterification and Hydrotreating Reactions of Rice Bran Oil for Bio-Hydrogenated Diesel Production

Two different methods of production of bio-hydrogenated diesel (BHD), simply called green diesel from rice bran oil (RBO), were performed. In the first route, a direct hydrotreating reaction of RBO to BHD catalysed by Pd/Al2O3 was performed in a high-pressure batch reactor. Operating conditions were investigated as follows: catalyst loading (0.5 to 1.5% wt.), temperature (325 to 400 degrees C), initial hydrogen (H-2) pressure (40 to 60 bar) and reaction time (30 to 90 min). The optimal condition was obtained at 1% wt catalyst loading, 350 degrees C, 40 bar H-2 pressure and 60 min. Yields of crude/refined biofuels and BHD achieved were approximately 98%, 81.71% and 73.71%, respectively. In another route, transesterification together with hydrotreating reactions of rice bran methyl ester (RBME) to BHD was performed using the optimal conditions obtained from the first route. The amount of 98% crude biofuel was obtained and was equivalent to production yields of refined biofuel (85.71%) and BHD (68.51%). Furthermore, physical and chemical properties of both RBO/RBME green diesel were also considered following ASTM standard methods. In summary, both catalytic reactions were achieved in the range of a low-speed industrial diesel and were further recommended for BHD or green diesel production from RBO.

Automated summary

Two different methods were used to produce bio-hydrogenated diesel (BHD), also known as green diesel, from rice bran oil (RBO). The first method involved a direct hydrotreating reaction catalyzed by Pd/Al2O3 in a high-pressure batch reactor, while the second method combined transesterification and hydrotreating reactions of rice bran methyl ester (RBME) to produce BHD. The optimal conditions for the reactions were determined and the yields of crude/refined biofuels and BHD were measured. The physical and chemical properties of RBO/RBME green diesel were also evaluated. Overall, both catalytic reactions were successful in achieving low-speed industrial diesel range and were recommended for BHD or green diesel production from RBO.