Study on pyrolysis and combustion characteristics of different plant fibers

In order to study the pyrolysis and combustion characteristics of different fibers, the kinetics of six kinds of plant fibers (coniferous, broadleaf, bamboo, flax, grass and cotton) in N₂ and air atmosphere were studied by non-isothermal thermogravimetric (TG) method using Friedman method. The results showed that the fibers had different pyrolysis and combustion characteristic parameters, which were related to their own structural compositions. In the process of pyrolysis and combustion of fibers, the initial volatilization temperature (T_s), terminal decomposition temperature (T_h), DTG peak temperature (T_max), fixed carbon combustion peak temperature, maximum mass loss rate, pyrolysis character index (P) and combustion character index (S) increased with the increase of heating rates; In N₂ atmosphere, the flax fiber T_max and bamboo fiber T_max were shown to be the highest and lowest among all fibers, respectively, and T_s of cotton fiber was the largest; Grass fiber had the smallest maximum pyrolysis mass loss rate (−(dm/dt)_max), pyrolysis index (P), and combustion index (S); Between the conversion of 0.05−0.85, the average apparent activation energies (E) of broadleaf fiber and bamboo fiber were the smallest (173.30 kJ/mol) and highest (201.10 kJ/mol), respectively. In air atmosphere, T_max of all fibers in the pyrolysis process was lower than that in N₂. The apparent activation energy (E_α) of fiber pyrolysis in air atmosphere was shown to be lower than that in N₂ when the conversion was between 5% and 65%.