Analysis of Bio‐Oil Derived from Catalytic Pyrolysis of Pine Sawdust over Sodium Salts‐Supported γ‐Al2O3

Abstract

Catalytic pyrolysis of pine sawdust with five sodium salts‐supported γ‐Al2O3 was performed in a fixed‐bed reactor at 500°C for liquid products. The liquid products were analyzed for its physics and chemical properties, such as product yield, oil phase proportion and yield, water content, chemical composition, elemental analysis, and calorific value. The results indicate that liquid yields decreased with the five catalysts compared with non‐catalytic pyrolysis, whereas phase separation (oil and aqueous phases) was observed. The oil phase water content drops sharply to around 10% compared to non‐catalytic bio‐oil (30%). The acid was not observed in the chemical composition of the oil phase product when the catalysts were present. The oxygen content of the oil phase products was significantly reduced. Of the five catalysts, Na2SiO3/γ‐Al2O3 catalyst showed better catalytic performance for its maximum oil phase product yield and oil quality. High heat value of the five oil phase products was all above 30.0 MJ/kg with this catalytic system. The new sodium ion species generated from the combination of sodium salts and γ‐Al2O3, which may be responsible to the improvement of bio‐oil quality. Furthermore, the excess sodium salts on the γ‐Al2O3 surface play an important role on the fast pyrolysis of pine sawdust. © 2019 American Institute of Chemical Engineers Environ Prog, 38:e13146, 2019