Co-pyrolysis of Lignin and Spent Bleaching Clay: Insight into the Catalytic Characteristic and Hydrogen Supply of Spent Bleaching Clay

This study aimed to clarify the catalytic characteristic and hydrogen supply of spent bleaching clay (SBC) in the pyrolysis of corncob lignin. The effects of lignin doping ratio (0%, 25%, 50%, 75%, and 100%) and pyrolysis temperature (450 degrees C, 550 degrees C, and 650 degrees C) on pyrolysis products were evaluated. The results of the kinetic analysis showed that when the lignin doping ratio was 75%, the activation energy was 51.753 kJ.mol(-1), which was lower than that achieved in lignin-only pyrolysis. When the lignin doping ratio was 75% (550 degrees C), the relative content of P-type phenols (methoxy-free phenols) was 23.08%, which reflected an increase of 34.23% relative to the theoretical value. Corncob lignin and SBC produced favorable synergistic effects during co pyrolysis, which promoted the production of P-type phenols (synergistic effect reached 134.44%) and aromatic hydrocarbons (synergistic effect reached 36.98%) and the inhibition of various oxygenated compounds. Concurrently, the mechanism of the synergy between lignin and SBC during co-pyrolysis was proposed based on the experimental results. This study could provide basic research and theoretical reference for the resource utilization of lignin and SBC waste.