Comparative study of the combustion and kinetic characteristics of fresh and naturally aged pine wood

Abstract

Given the long-term effects of natural ageing, the wooden structure and combustion performance of ancient buildings have changed. Therefore, studying the combustion characteristics of naturally aged pine (NAP) trees may help provide a basis for the numerical simulation of fires in ancient buildings. In this study, NAP and fresh pine (FP) with a natural ageing duration of approximately 100 years were selected as samples. The morphology, thermal weight loss process, exothermic characteristics, and combustion characteristics of these two types of pine were examined through scanning electron microscopy, synchronous thermal analysis, and cone calorimetry. In addition, the thermodynamic parameters of both the samples were analysed and evaluated. The results indicated that the natural ageing effect resulted in pore enlargement and severe damage to the cell structure of pine wood. Compared with FP, the ignite of NAP decreased by 15.2 °C, and the heat dissipation of NAP during oxidative combustion decreased by 0.26 kJ/g. In addition, the average apparent activation energy of NAP during pyrolysis combustion increased by 22.03 kJ/mol compared with FP, but the overall combustion performance decreased. During the combustion process, NAP tended to form a dense carbonisation layer, resulting in a decrease in the heat release rate, total heat release rate, flue gas release rate, and CO and CO2 release rate during combustion.