Sugarcane trash for energy purposes: Storage time and particle size can improve the quality of biomass for fuel?

In sugarcane (Saccharum officinarum) plantations, it was common to use fire to facilitate the cutting and harvesting of the sugarcane crop. The largest sugarcane producing state in Brazil is São Paulo, which has a planted area of about 4.7 million hectares. In the state of São Paulo law 11241/02 provides for the gradual elimination of the burning of sugarcane trash. It is estimated that one hectare produces about 14 tons of trash. The mills are trying to incorporate this trash with bagasse for power generation. The high concentration of mineral impurities is a problem in its use for energy purposes. The aim of the study was to investigate the influence of storage time and particle size on the physicochemical characterization of the sugarcane trash. The treatments were based on: the position of the bale (inner and surface), the storage time (0, 1 and 2 years) and the particle size (>0.420 mm, 0.250-0.420 mm, <0.250 mm and mix), totaling 24 treatments. The performed analyses were particle size distribution, proximate analysis, the higher heating value (HHV), the chemical analysis of the components of the ashes by Wavelength Dispersive X-ray Fluorescence (WDXRF) and the Scanning Electron Microscope (SEM) images. There were variations in the results of the ash content with different particle sizes. A higher concentration of mineral impurities in smaller particles (<0.250 mm) was observed. The HHV varied from 15.9 to 18.3 MJ kg−1 and showed no statistical difference between the treatments. The results indicate that the sugarcane trash presents problems related to mineral impurities which constrain its use as a solid fuel in industry. The particle size interferes in its physicochemical characteristics. The trash can be stored in the field and did not affect the quality for use as a solid biofuel.