Thermal Degradation of Rice Husks in Air and Nitrogen: Thermogravimetric and Kinetic Analyses

Abstract

In this study, thermogravimetric and kinetic data of thermal degradation of Malaysian rice husks under air or nitrogen atmospheres are analyzed. Determination of elemental composition, ash content, and gross calorific value of Malaysian rice husks and their comparison with other biomass fuel are also conducted. It is found that Malaysian rice husks have a gross calorific value of approximately 15 MJ/kg. Thermogravimetric analysis shows that significant thermal degradation occurs within temperature ranges of 230–380°C (nitrogen) and 230–540°C (air), which is primarily attributed to decomposition of hemicellulose and cellulose. Linear regression analysis using LINEST function in Microsoft Excel indicates that the nitrogen atmosphere data (order of reaction = 0.44) fit the Arrhenius model better than the air data (order of reaction = 0.22). The data obtained from our study can be used for preliminary evaluation of rice husks either as a combustible biomass or source for a small-scale thermochemical conversion system.

Keywords:

• biomass fuel
• elemental analysis
• LINEST function
• rice husks
• thermogravimetric analysis

Notes

Source: ^aMohamad-Yusof et al. (2008)

^b Arvelakis and Koukios (2002)

^c Demirbaş (2002).