KINETICS OF PYROLYSIS OF RICE HUSK

The pyrolysis of rice husk in both grain and powder form was investiga ted to determine the kinetic parameters. Experiments under non-isother mal conditions were carried out for rice husk grain and powder samples in nitrogen, and for rice husk grain samples in carbon dioxide at hea ting rates of 5, 10, 25, 50 and 100 degrees C/min. Experiments were al so carried out with rice husk grain samples in nitrogen under isotherm al conditions at temperatures 250, 275, 300, 350, 400, 450 and 500 deg rees C. From analysis of both the isothermal and non-isothermal data, it was found that pyrolysis proceeds in two distinct temperature zones with a transition at 350 degrees C. The reaction orders were found to be 1.5 in the lower temperature zone and 2.0 in the higher temperatur e zone. The kinetic parameters obtained from isothermal experiments we re found to be consistent with non-isothermal values. A method is prop osed for determining the pyrolysis rates at any heating rate. The meth od was found to predict satisfactorily the pyrolysis data at different heating rates of rice husk. (C) 1998 Elsevier Science Ltd. All rights reserved.