Catalytic pyrolysis of various biomass to aromatic hydrocarbons over Ni-based catalysts

The non-noble Ni-based catalyst has been attentive due to its low-cost and high activity in hydro-transfer reactions. However, the selective conversion is still lower compared to noble metal-based catalysts. In this study, we would like to design the modified Ni catalyst by co-doping P and Ce to form Nickel phosphide and bimetallic catalysts, which are supported in N-doping activated carbon. Aiming to study to convert agroforestry residues into valuable chemicals, which are further applied in Jet fuel, we investigated the effect of various biomass types as well as design Ni -based catalysts on upgrading fast pyrolysis oil. In detail, the research includes three parts: Part 1: Studying pyrolysis of 20 biomass samples in Thailand using data analysis to predict the pathway of phenolic formation, which was affected by biomass type and pyrolysis temperature. We found that a significant interaction relationship between lignin, hemicellulose, and pyrolysis temperature on the fraction of phenolic and aromatic hydrocarbon with rich-lignin biomass content and high temperature (550 – 600 °C) in fast catalytic pyrolysis can be an excessive solution to convert the waste material to high alkylphenol content. The statistic was performed to predict the yield of phenolic compounds from each fraction of lignocellulose with temperature. Part 2 and 3 are the development of nickel phosphide and bi-metallic of Ni-Ce support on N-doping activated charcoal for deoxygenation of pyrolyzed vapor from biomass pyrolysis in case of full H2 and limited H2 co-feeding gas, respectively. In the detail, the Ni2P/N-doping catalyst significantly influenced by the co-ordination of N-doping activated carbon to the formation of pure Ni2P phase with small particle size. The high selective alkylphenol product (>70%) was observed under mild temperature (300 – 400 °C), under atmospheric pressure in fixed-bed reactors. The Ni2P/CN50 catalyst can be applied in three cycles without treatment still performed high deoxygenation and prior better than without N-doping. Last part, the bi-metallic Ni-Ce catalysts with different Ni and Ce loading were tested with different co-feeding gas including H2, N2, CO2, and water. The estimated result is an in-situ generation of H2 by reforming and then immediately hydrodeoxygenation. The results show that the Ni-Ce bimetallic supported on N-doping activated carbon catalyst can be limited to the H2 atmosphere in hydrodeoxygenation up to 50%. However, to form full free-oxy by hydrodeoxygenation of lignin fragment under mild conditions (400 °C and 1 atm) without H2 gas co-feeding is still challenged.