High-pressure and high-temperature pyrolysis of poplar wood catalyzed by copper slag-Al2O3 composites: Enhancing syngas composition via thermal-chemical activation

Poplar wood chips, a by-product of the wood processing industry, can be ground into poplar wood powder (WP). Copper slag (CS), a low-value waste product generated from the copper smelting industry, becomes rich in Fe and contains small amounts of Cu and Mg after high-temperature calcination. This composition makes CS suitable for mixing with Al₂O₃ (CSA) as a biomass pyrolysis catalyst. This study aims at investigating the effect of CSA on the pyrolysis/gasification mechanism of WP under high-temperature and high-pressure conditions, focusing on changes in pyrolysis kinetics, thermodynamics, and gas products. Based on the ratio of CSA to WP, the mixtures are categorized as WP/CSA10 and WP/CSA5. The results revealed that the addition of CSA reduced the activation energy required for the reaction by 17 % and increased the thermal decomposition rate by 18 %. The analysis of pyrolysis products indicated that CSA facilitated the generation of H₂ and CO. In the high-temperature and high-pressure pyrolysis at 950 °C, the H₂ production increased by 14 % and the CO production increased by 12 %. These results demonstrate the significant catalytic effect of CSA. This approach not only addresses the environmental burden of waste copper slag but also provides a theoretical foundation for optimizing the catalytic pyrolysis process and promoting the high-value utilization of WP.