Process development and simulation of glycerol-free biofuel from canola oil and dimethyl carbonate

• Dimethyl carbonate transesterification eliminates glycerol byproduct and wastewater.
• Minimum number of unit operations and minimized energy usage
• Value added byproducts — glycerol carbonate and glycerol dicarbonate
• Alternate biodiesel formulation meets ASTM D6751 standard.

Biofuels, especially biodiesel, have become commonplace over the last couple of decades. The conventional transesterification process used for biodiesel production leaves manufacturers with a byproduct, glycerol, that is of low value. Dimethyl carbonate has been studied as an alternate methylating agent to methanol and alters the chemistry such that glycerol is not formed. Triazabicyclodecene was chosen as the catalyst due to its ability to easily ionize the dimethyl carbonate and ease of separation post reaction.This paper reports on the development of specific processing steps to convert canola oil to FAMEs and fatty acid glycerol carbonate (FAGCs) compounds. The process flow diagram was developed using Aspen Plus simulation software and verified through laboratory testing. Process conditions were adjusted until a glycerol-free biofuel was produced that meets the ASTM D6751 standard for biodiesel. By utilizing the glycerol moiety within the final product, about 9.7% increase (by mass) of biofuel was obtained compared to the traditional methanol synthesis route. Glycerol carbonate and glycerol dicarbonate were formed as byproducts but were in low concentrations. These results reveal the potential of using dimethyl carbonate as a replacement for methanol to produce an acceptable, more environmentally friendly biofuel.