Efficient hydrodeoxygenation of guaiacol and fast-pyrolysis oil from rice straw over PtNiMo/SBA-15 catalyst for co-processing in fluid catalytic cracking process

Abstract

Fast pyrolysis of renewable biomass is an attractive approach to convert solid biomass into a liquid which has higher energy density. However, pyrolysis oil has high acidity, low energy value, high viscocity and instability that limit end-user applications. This study focuses on the upgrading of pyrolysis oil using hydrodeoxygenation (HDO) process to produce a suitable bio-oil that can be further co-processed in standard refinery. In the first part, Pt was added to NiMo/SBA-15 catalyst in order to improve the HDO activity of guaiacol (GUA) and of fast pyrolysis oil from rice straw. Pt addition leads to important increases in both GUA conversion and HDO degree, and more interestingly, to the domination of saturated cyclic compounds (80–95 %) among formed products. Temperature programed reduction analysis proved that the reduction of Ni and Mo species occurred at lower temperatures with the presence of Pt. The use of 0.7 PtNiMo/SBA-15 catalyst resulted in the very high GUA conversion (94.5 %), high HDO degree (98.7 %), and high saturated cyclic compounds selectivity (97.4 %). In addition, the HDO treatment of fast pyrolysis oil over this catalyst at 300 °C, 12 MPa leads to a decrease in oxygen content from 44 wt.% to 20 wt.%. Then, the second part of this work has shown that HDO bio-oil obtained can be co-processed (up to 20 wt.% of bio-oil) with vacuum gasoil (VGO) in fluid catalytic cracking lab-scale unit (short contact time micro-activity unit, SCT-MAT) without significant change of the yield of profitable products: liquid petroleum gas, gasoline and light cycle oil.