Green Diesel: A Second Generation Biofuel

Environmentally-conscious design of processes and products is increasingly viewed as an important strategy in the sustainable development of new refining and chemical processes. This paper discusses a new process technology developed by UOP and Eni S.p.A; the UOP/Eni EcofiningTM process to produce green diesel from vegetable oil. This novel process utilizes catalytic saturation, hydrodeoxygenation, decarboxylation and hydroisomerization reactions to produce an isoparaffin-rich diesel fuel from renewable feedstock containing triglycerides and fatty acids. The resultant biofuel product has a high cetane value, a lower gravity, good cold flow properties and excellent storage stability. Green diesel is completely compatible for blending with the standard mix of petroleum-derived diesel fuels, thus providing significant value to the refiner. The process for producing green diesel operates at mild operating conditions and integrates well within existing petroleum refineries. In contrast to fatty acid methyl esters, where fuel properties depend on feed origin and process configuration, green diesel product is independent of feed origin and the fully deoxygenated biofuel is readily blended with conventional diesel fuel. A life cycle assessment (LCA) of this promising new biofuel production technology has been undertaken to quantify the intrinsic benefits of green diesel production over the current practice of converting various forms of lipids to fatty acid methyl esters. This paper will describe the technology, discuss the results of the LCA study and summarize the advantages this new technology can offer over other processing routes.