Research on pyrolysis characteristics and product regulation mechanisms of biomass thermal dissolution residues

This study investigates the carbonization behavior of biomass TD residues (PsR, CbR, EpR) and their pyrolysis product distribution. Fixed-bed experiments were conducted to examine the effects of temperature (400–600°C) and heating rate (5–25 °C/min) on biochar properties, product yields, and gas/bio-oil composition. Results show that the residues' low-oxygen, high-carbon nature favors high-quality biochar production. Higher temperatures increased gas yield but reduced biochar formation, while faster heating rates enhanced bio-oil and gas generation via intensified depolymerization. Bio-oil mainly contained aromatics and phenols, with their contents rising at elevated temperatures and heating rates. At 600°C and 10 °C/min, pyrolysis gas contained over 60 % combustible components (CO, CH₄, H₂). Biochar exhibits excellent fuel performance, with PsR_biochar and CbR_biochar displaying a hierarchical pore structure, while EpR_biochar has its pores blocked due to ash melting. Mesoporous PsR_biochar was obtained at 500°C and at 10 °C/min, while higher temperatures and heating rates improved adsorption capacity. This work provides insights into optimizing pyrolysis conditions for high-value utilization of biomass refining residues, supporting a clean production process and resource recycling.