Thermal conversion of cellulose fiber under slow pyrolysis: Kinetics, thermodynamics and related chemical species

Abstract

This study discusses the thermal conversion of cellulose fiber and the governing kinetic, chemical and thermodynamic phenomena. Activation energy ($E_a$) and pre-exponential factor (A) were evaluated for the range of temperature [20–600 °C] under three low heating rates 1.5, 2.5 and 5 °C min⁻¹ using different model-free and model-fitting methods and are around 205 kJ mol⁻¹ and 2.4 × 10⁺²⁰ s⁻¹, respectively. Coats-Redfern method was used to identify the thermal degradation reaction mechanism. Biobased carbonized fiber yield increases with lower heating rate and goes from 15.5 % for 5 °C min⁻¹ to 19 % for 1.5 °C min⁻¹ through a spontaneous endothermic process. The evolution of prominent volatiles and light gases was evaluated by mass spectrometry and gas chromatography combined with Fourier Transform InfraRed spectroscopy. This study may be useful for future research into bio-based carbonized fibers, and their applicability on an industrial scale with considering all related parameters.