Volatile-char interactions during biomass pyrolysis: Effect of decoupled primary and secondary interactions on product control

Abstract

This paper proposes an innovative double-layer reactor that decouples volatile-char interactions into distinct primary and secondary interactions, allowing for a systematic investigation of their respective effects on the pyrolysis behavior of poplar wood (PW) and the characteristics of the resulting products. Following primary interactions, a significant enhancement in bio-oil yield was observed, reaching 57.92 wt%, with anhydrosugars accounting for 13.27 % of the bio-oil composition. Concurrently, the non-condensable gas composition exhibited substantial concentrations of CO and CH₄, constituting 29.05 % and 12.26 % of the gaseous products, respectively. Through controlled secondary interactions, the content of phenols and other aromatics in bio-oil ultimately reached 55.08 %. Simultaneously, the added activated carbon in interlayer demonstrated significant compositional modifications that the volatile content increased from 3.78 to 9.77 wt%, accompanied by a corresponding reduction in oxygen content to 5.73 wt%. The pore structure of activated carbon was also altered after secondary interactions. The innovative double-layer reactor enables precise control over pyrolysis product distribution and quality through its two-stage volatile-char interaction mechanism, establishing a technologically viable pathway for industrial-scale valorization of waste biomass.