Kinetic Modeling of Rice Husk Components Pyrolysis Based on Independent Parallel Reactions

Abstract

This study presents the pyrolysis mechanism of rice husk in nitrogen atmosphere by thermogravimetric analysis (TGA). The thermal decomposition wasout in three stages: moisture removal(18--200 oc), main devolatilization 200- 400 oc) and continuous slight devolatilization (400 oc). The weight loss of rice husk was based on the assumption that lignocellulose components (cellulose, hemicellulose and lignin) undergo pyrolysis independently in parallel first-order reactions. The kinetic parameters of the three lignocellulose components were determined by means of Microsoft Excel Solver tool using least square algorithrn. The result of thermal degradation of rice husk samples shows that the predictions of the cellulose, hemicellulose and lignin components with the experiments. The activation energy and pre-exponential factors of cellulose, hemicellulose and lignin are 187kJ/mol and 1.2x 10^15 min^-1, 29kJ/mol and 1.6x10^7min^-1 and 90 kJ/mol and 1.8 x 10^-1. The results suggest that thermal rate of cellulose was found to be higher, whereas that of lignin decomposition rate was lower. The thermal of hemicellulose decomposition was intermediate.