Comparison of the combustion behaviours of agricultural wastes under dry air and oxygen

Abstract

Burning tests of some agricultural waste biomass materials such as sunflower seed shell (SSS), hazelnut shell (HS), rice hull (RH), and olive refuse (OR) were performed in order to compare the combustion reactivities of these materials under dry air and oxygen. For this purpose, these samples were burned in a thermal analyzer to obtain TGA (Thermogravimetric Analysis), DTG (Derivative Thermogravimetry), DTA (Differential Thermal Analysis), and DSC (Differential Scanning Calorimetry) thermograms under both conditions. Initial sample mass was approximately 10 mg for each sample which has a particle size of <0.25 mm, and temperature was raised from ambient to 900°C with a linear heating rate of 40°C/min under gas flow rate of 100 mL/min. No hold time was allowed at the final temperature. The results of this study showed that the thermal reactivities of biomass species change in a wide region, and the type of the oxidative medium plays very important effects on the burning parameters such as the ignition point, maximum rate of combustion and its temperature, as well as the end point of burning. On the other hand, macromolecular ingredients of biomass such as hemicellulosics, celluloses, and lignin have significant effects on the combustion behavior of biomass.