Characterizing potassium-assisted lignocellulose pyrolysis process based on the multi-parallel compensation-simplified distributed activated energy model (CS-DAEM)

Potassium-assisted biomass pyrolysis is highly efficient for product poly-generation and upgrading. In this study, kinetics modeling of over-saturated potassium (K₂CO₃)-assisted lignocellulose pyrolysis process was carried out by using the modified Friedman-based master plot (MF-MP) method combined with multiple-parallel compensation-simplified distributed activation energy model (CS-DAEM). The effects of K₂CO₃ dosage on the lignocellulose pyrolysis process were also studied. MF-MP results show that all the K₂CO₃-assisted pyrolysis processes of cellulose, xylan, and lignin obey the Avrami-Erofeev (Am) nucleation mechanism, where potassium slightly decreases the activation energies. The potassium-assisted pyrolysis process of typical lignocellulose (bamboo) also obeys the Am mechanism, and 3G-Am-CS-DAEM modeling of the processes achieves R² > 0.999. By fixing the pre-exponential factor, the compensation effect was simplified. Based on modeling results, the activation energy decreases as potassium dosage increases from 0.01 mmol/g to 10 mmol/g. This study provides an effective kinetics approach to characterize the potassium-assisted biomass pyrolysis process.