Continuous pyrolysis of pine sawdust at different pyrolysis temperatures and solid residence times

• The influence of pyrolysis temperature and solid residence time on products and energy distribution were investigated.
• The results showed that carbon monoxide is the main component in bio-gas.
• The oil products showed that phenols hydrocarbons were the major components.
• The maximum of energy profit rate is 6.49% obtained at the temperature of 900 °C with the solid residence time of 6 min.

In this work, the continuous pyrolysis of pine sawdust is performed with a screw reactor to investigate the influence of pyrolysis temperature and solid residence time on products and energy distribution. Gas chromatograph/mass spectrometer (GC/MS) and Fourier transform infrared spectroscopy (FTIR) were used to confirm the identities of bio-oil. The combustion kinetics of bio-char had analyzed by thermo-gravimetric (TG). The results of gas chromatograph showed that carbon monoxide is the main component in produced gas, and the maximum gas yield of 54.5% was obtained at the temperature of 900 °C. Compositional analysis of the oil products showed that phenols were the major components, and its proportion increased at higher temperatures and longer solid residence times. The activation energy of bio-char combustion is 461.10 kJ mol−1 and 108.45 kJ mol−1 in the ranges of 290–314 °C and 314–518 °C, respectively. The maximum of energy profit rate is 6.49% obtained at the temperature of 900 °C with the solid residence time of 6 min.