The thermal degradation of lignin for value-added fuels and chemicals is important for environment improvement and sustainable development. The impact of pretreatment and catalysis of Ni(NO3)2 on the pyrolysis behavior of organsolv lignin were studied in the present work. Samples were pyrolyzed at 500 ∘C with an upward fixed bed, and the characteristics of bio-oil were determined. After pretreatment by Ni(NO3)2, the yield of monophenols increased from 23.3 wt.% to 30.2 wt.% in “Ni-washed” and decreased slightly from 23.3 wt.% to 20.3 wt.% in “Ni-unwashed”. Meanwhile, the selective formation of vinyl-monophenols was promoted in “Ni-unwashed”, which indicated that the existence of nickel species promoted the dehydration of C-OH and breakage of C-C in pyrolysis. In comparison with “Water”, HHV of bio-oil derived from “Ni-unwashed” slightly increased from 27.94 mJ/kg to 28.46 mJ/kg, suggesting that the lowering of oxygen content in bio-oil is associated with improved quality. Furthermore, the content of H2 in gas products dramatically increased from 2.0% to 7.6% and 17.1%, respectively.
Effect of Ni(NO3)2 Pretreatment on the Pyrolysis of Organsolv Lignin Derived from Corncob Residue