Discovery and intensity characterization of TDP and PRP based on temperature evolution history during the pyrolysis for large biomass particle

The pyrolysis behaviors and temperature evolution history of lignocellulosic biomass (Beech, BH) were characterized using a novel pyrolysis model—C-DAEM. The simulation results were validated through corresponding experimental data. Based on the simulation results, two distinct peaks were observed in the temperature difference between the surface and center (TDSC) curve, namely the thermal disturbance peak (TDP) and the pyrolysis reaction peak (PRP). The presence of TDP and PRP was confirmed by examining the heat flux ratio between the pyrolysis rate and the temperature rise rate. Moreover, the results indicated that three factors, namely heating temperature, particle size, and pyrolysis rate, influenced the relative intensity between TDP and PRP. By changing the values of each impact factor, conditions where TDP owns the same height with PRP were obtained under different working conditions. These findings have led to the development of a dimensionless number, naming the pyrolysis-heating surface-center number (PH_SC number). This number could provide a comprehensive indication of the collective impact of the aforementioned factors when TDP and PRP exhibit equal peak heights.