Pyrolysis kinetics of potassium-impregnated rubberwood analyzed by evolutionary computation

Abstract

To explore the catalytic effect of potassium on pyrolysis characteristics of biomass, the rubberwood is pyrolyzed by a thermogravimetric analyzer. The samples are impregnated by three concentrations of potassium carbonate (0.004 M, 0.008 M, and 0.012 M). The pyrolysis kinetics is analyzed by an independent parallel reaction (IPR) model to describe the catalytic effect on the four-pseudo components model in the rubberwood. The particle swarm optimization (PSO) is adopted to optimize the fit quality between the established kinetic models and experimental data. It is found that the pyrolysis of rubberwood impregnated with 0.012 M concentration of K₂CO₃ can reduce the activation energy of cellulose from 223.86 to 204.14 kJ mol^-1, whereas there is no obvious effect on the activation energies of hemicelluloses and lignin. The starting temperature and ending temperature of cellulose thermodegradation also move toward lower temperatures, indicating that the addition of potassium enhances the degradation of cellulose.

Keywords: Impregnation; Independent parallel reaction (IPR) model; Lignocellulosic biomass; Particle swarm optimization (PSO); Potassium catalyst; Pyrolysis kinetics.