“…The two stages of pine pyrolysis are clearly distinguishable: (i) for α=0.06-0.8 fragmentation of hemicelluloses, cellulose and lignin occurs [83,84], whose respective energy barriers of 55-187, 195-236 and 35-267 kJ/mol had been determined [28]; and (ii) between α=0.81-0.91, whose high energy barrier is due to the formation of a complex polycyclic aromatic structure (char formation) [28,84]. It should be noted that thermal decomposition of lignin occurs during the entire process, especially at high temperatures, which demonstrates the wide variety of bonds in its structure [28,83]. Similar to the results reported here, Yao et al [85] obtained, using Friedman's method, a mean activation energy of 161.5±3…”