煤矸石–玉米秸秆共热解多段集总动力学与主成分特征解析

Extensive research has been conducted on the co-combustion of coal gangue (CG) and biomass; however， the co-pyrolysis behavior remains insufficiently explored. In this study，coal gangue (CG) and corn straw (CS) were used as research objects. The pyrolysis characteristics are systematically investigated，kinetic mechanisms，and synergistic interactions between CG and corn straw (CS) using thermogravimetric analysis (TGA)，a multi-stage lumped reaction kinetic model，and principal component analysis (PCA). The results indicatethat CG pyrolysis occurs single-stage (main peak at 501 ℃)，whereas CS pyrolysis exhibits three distinct stages (210，291，and 440 ℃)，primarily corresponding to the decomposition of hemicellulose，cellulose and lignin，respectively. During co-pyrolysis，CG shifted the DTG peak to higher temperatures，and at the CG proportion ≥70%，it dominated the high temperature pyrolysis regime (480−750 ℃). Kinetic analysis revealedthat the pyrolysis of CS contained five lumped reactions (A—E)，of which the 292 ℃ reaction (dominated by cellulose) accounted for 50% participation，whereas CG was mainly controlled by the 517 ℃ reaction (64% participation). The mixed system showed superposition and competition of characteristic reactions. Interaction analysis showed that CG inhibited cellulose pyrolysis in the low temperature zone (<350 ℃) ，with the strongest suppression observed CG7CS3 (ΔW=+4.69%). Conversely，CG and lignin exhibited synergistic promotionat e higher temperatures (>350 ℃) ，with CG3CS7 showing the greatest enhancement(ΔW=−8.50%). PCA analysis confirmed that CG optimized the pyrolysis process，CG5CS5 enhanced the low-temperature ractivity，while CG dominated the high-temperature regime. The stage-dependent synergistic mechanisms of CG/CS co-pyrolysis are elucidated, and CG3CS7 is identified as the optimal blend for maximizing volatile release and energy conversion efficiency. Additionally, the pyrolysis characteristics are systematically investigated. The findings provide a theoretical foundation for the sustainable thermochemical utilization of coal-based solid waste and agricultural biomass.