Hydrodeoxygenation of triglycerides for the production of green diesel: Role of heterogeneous catalysis

Catalytic hydrodeoxygenation of triglycerides is a prominent technology in hydrocarbon biorefinery for producing diesel-range biofuels, named green diesel. The triglycerides are fatty ester of glycerol associated with three long-chain fatty acids. While the triglycerides are generally composed of C8-C24 fatty acids, the majority of the fatty acids are in the diesel range (C16 and C18). The removal of oxygen from triglycerides thus produces green diesel. Therefore, the present chapter provides an overview of the hydrodeoxygenation of triglycerides. The process involves a combination of hydrogenation, hydrodeoxygenation, and decarbonylation reactions. This chapter also covers the impact of metal-based catalysts and process conditions on the reaction mechanism and composition, fuel properties, and yield of green diesel. The fuel characteristics of green diesel demonstrate that it can be used directly in an unmodified combustion engine. This chapter further covers the commercial status and economic viability of this technology.