THERMAL-DEGRADATION OF RICE HUSKS IN NITROGEN ATMOSPHERE

Rice husk, a renewable by-product of rice milling operations, is an en ergy source that can be utilized to meet the increasing demands for en ergy. Its utilization can also help rice millers meet increasing costs of rice husk disposal because of increasing restrictions on disposal. However industrial utilization of rice husk in thermochemical convers ion systems to liberate energy requires the knowledge of its thermal c haracteristics for the proper design and modelling of these systems. T he thermal degradation of four rice husk varieties (Lemont, ROK 14, CP 4, and Pa Potho) were investigated at three heating rates (10, 20 and 50 degrees C/min) in nitrogen atmosphere using the technique of therm ogravimetric analysis between ambient temperature and 700 degrees C. T he thermal degradation rate in active and passive pyrolysis zones, the initial degradation temperature, and the residual weight at 700 degre es C were determined. Increasing the heating rate increased both the t hermal degradation rate and the residual weight at 700 degrees C, and decreased the initial degradation temperature. The higher the cellulos ic content of the rice husk, the higher the thermal degradation rare a nd the initial degradation temperature. Also, higher ash content in th e rice husk resulted in higher residual weight ait 700 degrees C. Rice husk could be degraded to the extent of 56-64%. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.