Catalytic hydrotreatment of fast pyrolysis oils using Ni-Cu/Al-MCM-41 catalysts

This work aims to study Ni and Cu-based catalysts supported by Al-MCM-41 applied in the hydrodeoxygenation (HDO) of pyrolysis oils from pinewood and sisal residue. The catalysts were synthesized with different Ni and Cu loadings by the wet impregnation method and used in HDO reactions in a batch autoclave reactor. The activities of the catalysts and the distribution and characteristics of the products obtained by each were explored and evaluated comparatively with the benchmark Ru/C catalyst. The results for the pinewood bio-oil showed that the Ni-Cu/Al-MCM-41 catalysts promoted higher yields of the organic phase and monomers detected by GCxGC, a reduction in the average Mw and the O/C ratio, as well as an increase in the H/C ratio, indicating a predominance of the hydrogenation/hydrodeoxygenation/hydrocracking route. Regarding the HDO reactions with the sisal residue bio-oil, the re-polymerization route was predominant, resulting in a lower H2 uptake, an increase in average Mw, and a decrease in monomer yields. However, the O/C ratio was reduced compared to the feed. The 20Ni5Cu and 20Ni10Cu were the best catalysts for HDO of both pyrolysis oils tested and showed significant aliphatic and aromatic hydrocarbon production.