Green Diesel Production - An Overview

Currently, there are two renewable diesel fuels available: biodiesel and green diesel. The biodiesel or FAME is the transesterification of vegetable oil or animal fat with methanol. The green diesel, which uses the same or similar feed stocks as biodiesel, is produced by a hydrotreating process that is widely employed in the modern petroleum refineries. Hydrogen is added to oil or fat resulting and quality of the renewable diesel fuel is significantly improved. It can be produced in a standing-alone unit or processing with conventional petroleum feedstock for the diesel fuels production. However, unlike the petroleum feedstock, the feed for the green diesels contains significant amount of oxygen and olefins, which can impose additional challenges for design and operations of the hydroprocessing unit.

The paper will discuss the feedstock selection and its impacts on the product quality. The process chemistry, catalyst selection, and heat balance will be also discussed. Some characteristics of the green diesel process, such as high hydrogen consumption, high heat release, and unique issues related to the carbon dioxide and carbon monoxide as the process byproducts will be included.