Abstract:

In order to obtain the pyrolysis characteristics of Pinus Sylvestriformis and prevent forest fires, the pyrolysis process was carried out using the branches, cones, bark, and pine needles of P. Syluestriformis. The pyrolysis kinetics analysis was conducted by the Coats-Redfern method, and the influence of various factors on the pyrolysis of P. sylvestriformis was explored using the cones as the research object. Experimental results showed that the pyrolysis process of the four materials could be divided into four stages, where the mass loss rate of the main weightless stage occupied about 60%. The higher heating rate, the less sufficient pyrolysis. There was a thermal hysteresis phenomenon, where the minimum mass loss rate was 80.34% at 25℃/min. Particle size had little influence on TG and DTG curves. The smaller particle size, the more uniform internal and external heating, and the maximum mass loss rate of the materials with a particle size of 0.20 mm was 91.18%. There was a peak of weight loss in the main weight loss stage under nitrogen atmosphere, and two peaks of weight loss under air atmosphere. The pyrolysis time of P. sylvestriformis cones in high pure air was longer, the pyrolysis was more complete, and the promotion effect was stronger, with the weight loss rate of 98.14%. The results of pyrolysis kinetic analysis showed that the optimal mechanism function of the four materials was "three-dimensional diffusion". The branches had the highest activation energy(157.04 kJ/mol), and the lowest value was found in pine needles(98.19 kJ/mol). In addition, the activation energies for the cones and bark were 148.08 and 115.04 kJ/mol, respectively. Therefore, special attention should be paid to the fire prevention of pine needles and bark.

Key words: Pinus sylvestriformis, thermogravimetric analysis, dynamic analysis