Effect of Dual-Site Supported Carbon-Fixation Materials on the Char Yield of Bamboo Powder Pyrolysis
A supported carbon-fixation material was prepared by rotary evaporation using K2CO3 and P2O5 as active components and bamboo powder as the carrier, and its effect on bamboo powder pyrolysis was investigated. Under identical pyrolysis conditions, the dual-site supported carbon-fixation material increased the dry-basis char yield of bamboo powder from 49.7% to 53.1%, while the air-dried high heating value of the corresponding char remained essentially unchanged. Characterization indicated that the carbon-fixation effect originates from a three-dimensional network structure formed by P and K active components on the bamboo powder surface, which effectively promotes secondary cracking of pyrolysis gas at the surface and enhances char yield. The addition of the dual-site supported carbon-fixation material increased the ash content of bamboo char from 0.86% to 0.96%, with no significant influence on the combustion characteristics of the char. In contrast, single-site K2CO3-loaded materials promoted pyrolysis but reduced char yield: at 15% K2CO3 loading, the dry-basis char yield decreased to 30.3% and the char heating value increased to 26.67 MJ/kg, representing a 39% decrease in char yield and a 14.1% increase in heating value relative to raw bamboo powder. The dual-site formulation therefore resolves the trade-off between catalytic activity and carbon retention, providing a low-cost route for biomass pyrolysis carbonization.