Determination of Physical and Chemical Properties of Rice Straw and the Energy Required for its Grinding

Limitation of fossil fuels and the growing awareness of the detrimental environmental consequences resulting from greenhouse gas emissions have reinforced the importance of biomass as an energy resource. The conversion of rice straw and rice bran into briquettes as solid fuel is an important issue. The aim of this study was to determine the physical and chemical properties of rice straw and rice bran, and also the energy required for milling rice straw by hammer mill. Particle size distribution and particle density were determined for the milled straws, produced by four sizes of hammer mill screens at six particle size levels. FTIR test was carried out for determination of rice straw factor groups and distinction relation test. The required energy for grinding decreased with increasing of moisture content of the materials and the size of hammer mill screen. Normal distribution was observed for particle sizes of rice straw, grinded at 2 and 4 mm hammer mill screen sizes. The friction angle and bulk density of rice straw decreased with increasing the rice straw particle size. For the friction surfaces, the highest and lowest friction angles belonged to iron and aluminum surfaces, respectively. Based on the results of FTIR, during the burning process, lignin was fully destroyed in the oxidation reaction.