Pyrolysis of tropical hardwood under long-term and low-temperature conditions

Abstract

Pyrolysis experiments were carried out on Kapur and Nyatoh hardwood species in ovens isothermally at low temperatures 160 °C, 175 °C and 190 °C for extended durations up to 153 days in aerobic condition. Oxygen chemisorption and functionality of chars were analysed using thermogravimetric analysis (TGA) and Fourier transform infrared (FTIR) spectroscopy. Pyrolysis kinetic models for Nyatoh and Kapur wood under isothermal conditions in air were developed based on weight loss history. Thermal degradation of wood samples in the study followed a first order reaction process after the initial period of fast degradation. The model can be used to estimate the heating period to reach different degrees of degradation under air condition as a function of temperature and to predict the duration to reach the final stage where self ignition is most likely at a particular low temperature. The study has shown that chars created at low temperature for long duration in aerobic condition were susceptible to oxygen chemisorption. Results indicated that they were reactive and prone to self ignition