(2021) Energy_Catalytic pyrolysis of pine bark over Ni/SiO₂ in a CO₂ atmosphere

Lee T., Jung S., Kim K.-H., Kwon E.E.

(Elsevier Ltd) Energy ISSN: 3605442 Vol.220 Issue. Article No.119827 DOI: 10.1016/j.energy.2021.119827

Syngas was produced by catalytic pyrolysis of pine bark (PB) using CO₂ as a raw feedstock as part of an effort to realize the sustainable utilization of biomass carbon. An examination of both liquid and gaseous pyrolysates from pyrolysis revealed that CO₂ expedited gas-phase reactions (GPRs) with volatile pyrolysates (VPs) evolved from thermolysis of PB. The GPRs between CO₂ and VPs led to the generation of CO at ≥ 600 °C regardless of Boudouard reactions. Two-step pyrolysis was conducted with an additional heating source, and the synergetic use of Ni/SiO₂ and CO₂ stimulated syngas formation at ≤ 600 °C. Evolution of H₂ and CO from catalytic pyrolysis at 700 °C in CO₂ atmosphere was greater by factors of 10 and 5, respectively, compared with those from two-step pyrolysis. The conditions for catalytic deactivation between virgin and used catalysts were compared using temperature-programmed oxidation. An apparent reduction of organic species on the surface of used catalysts by CO₂ indicates that the addition of CO₂ suppressed the formation of coke for deposition. Accordingly, combinational use of CO₂ and Ni/SiO₂ in catalytic pyrolysis can be recommended as an advanced technical option for production of syngas under favorably retarded conditions for catalyst deactivation. © 2021 Elsevier Ltd

This work was supported by National Research Foundation of Korea grants funded by the Korea government ( MSIT ) ( NRF-2019H1A2A1076293 and NRF-2019R1A4A1027795 ).