The Influence of Temperature on the Degree of Bio-Oil Hydroupgrading over High-Loaded NiCu-SiO2 Catalyst at Low Hydrogen Content

Abstract

The process of upgrading of pyrolysis bio-oil via hydrodeoxygenation was studied at 0.6 MPa hydrogen pressure and 150–350 °C in the presence of the NiCu-SiO2catalyst prepared by the sol-gel method. The catalyst resistance to agglomeration of the active component and to the carbon deposition on its surface was examined. The oxygen content in the liquid products of lignocellulose pyrolysis was shown to decrease from 37 to 15 wt.% as the process temperature rose. A CHNS-O analyzer was used to establish that the coke quantity on the catalyst surface at 350 °C decreased to one fourth of that at 150 °C. XPS studies revealed that the elevation of the process temperature led to progressive agglomeration of the particles followed by a decrease in their size at high temperature due to dissolution of the active components of the catalyst in the reaction medium.