Options for generation of sustainable energy: production of pellets based on combinations between lignocellulosic biomasses

Abstract

Brazil has a highlighted position in comparison to other countries in relation to the amount of renewable raw materials, as the lignocellulosic wastes, and technologies for production of alternative energy. The aim of the study was to evaluate the potential of lignocellulosic wastes such as: from soybean culture, sugarcane bagasse and eucalyptus wood for pellets production focusing the generation of heat energy, and classify them according to the commercialization standards. The properties as heating value, bulk density, energetic density and proximate analysis of the biomasses were evaluated. The pellets were produced with diameter of 6 mm in a horizontal planar array pelletizer. The raw material used generated pellets with eucalyptus and soybean wastes mixed in different proportions, as well was done for sugarcane bagasse and soybean wastes. These mixtures were compared to pellets composed by 100% soybean wastes, 100% sugarcane bagasse and commercial pellets produced with pine wood. The pellets were evaluated through the physical properties (moisture, bulk density and unitary density), energetic properties (heating value and energetic density), chemical properties (volatiles, fixed carbon and ash) and mechanical properties (hardness and mechanical durability). Among the pellets produced, the 100% sugarcane bagasse highlighted by high values for mechanical durability (96.64%), hardness (39.46 kgf) and energetic densities, besides low production of fines (0.18%). Pellets composed by the tested mixtures obtained higher values for heating value, mechanical durability, hardness and lower fines and ashes content in comparison to the pellets composed only by soybean wastes. The increasing of eucalyptus sawdust percentage in the pellets decreased their ashes content in comparison to the 100% soybean wastes (from 26.72 to 14.03%). The sugarcane bagasse pellets showed similar properties to the commercial ones.