Hydrotreating of Biooils to Jet Fuels: An Overview

This paper will give an overview of the current status of jet fuels production from hydrotreating of biooils, including vegetable oils and microalgae oils.  Hydrotreating of biooils is different from the conventional hydrotreating process; there are two reasons:

1) Different routes.  There are at least four different kinds of chemical reactions in the hydrotreating of biooils: hydrodeoxygenation,  hydrodecarboxylation, hydrocracking and hydrogenation of unsaturated chemical bonds. 

2) Different heteroatoms contaminants in the feedstock.  This effect includes the inhibitory actions of the byproducts of the reactions with hydrogen.  Sulfur concentration is much lower in biooils than that in conventional fossil fuels, while phosphorus contaminant in biooils is much higher.  Phosphorus originates from phospholipids in biomass feedstock.  Phospholipids removal is required in biofuels production.   

Traditional hydrodesulfurization catalysts can still be used for hydrotreating of biooils, however, the catalyst lifetimes are much shorter.  Future catalysts for biooils hydrotreating should be more selective for hydrodeoxygenation and be able to tolerate phosphorus contaminants.  This paper will address the bioils pretreatment requirement and the direction for the development of biooils hydrotreating catalyst as well as product property adjustment.