Characterization of residues generated in the harvest and processing of pomiculture for energy purposes in polydispersed fluidized beds

Abstract

Brazil is prominent in world fruit production, behind only China and India. Orange, banana and apple are the most cultivated fruits nationally. According to the Food and Agriculture Organization (2012), apple is the second most consumed fruit in natura in the world. Apple production generates a large amount of waste, from the orchard to storage, and in the processing industry. Pruning is the stage of production in which more waste is generated, and an average of 5 tons / ha of wood residue can be estimated. In the classification and storage stage, fruits that do not fall into the commercial categories are destined to the processing industry, where, after the processing, the residue is the bagasse. Considering the great energetic potential of these residues, it is interesting to study their use in biorefinery processes. The objective of this study is to investigate the potential use of the residues of the pomicultura (branches, leaves and apple of discard) in processes of biorrefinaria for energetic purposes. For this, the residue samples were characterized for their thermochemical and thermogravimetric properties, and were tested in laboratory scale fluidization equipment. The upper calorific value for apple tree branch, apple leaf and discard was 18,427 MJ / kg, 19,900 MJ / kg and 16,501 MJ / kg, respectively. In the thermogravimetric curves, the zones were observed the mass losses related to the moisture content of the sample, at 100 ° C, related to degradation of cellulose, hemicelluloses and lignin, at 230 ° C, 260 ° C and 350 ° C respectively. The samples tested in the bed corresponded to mixtures between biomass and sand, used as an inert material. The biomass mass percentages present in the tested mixtures were 10%, 30%, 50%, 70% and 90%. For mixtures containing 10%, 30% and 50% of the biomass volume, the fluidization characteristic curves were observed. In fluidization for mixtures with 50% of its volume composed of biomass, despite the formation of preferred paths, it was possible to verify the fluidization phenomenon. What was not possible to verify In the mixtures containing a volume of 70-90% of biomass. However, in these mixtures, two cases were observed: formation of large preferential paths and segregation of particles. Comparing the physical characteristics with eucalyptus and pinus biomasses, which fluidize with mixtures of 70% of the biomass volume, the non-fluidization of the mixture containing a volume greater than 50% of apple tree branches may possibly be explained by the difference in the shape of the particles . However, it was possible to conclude that the use of waste from apple production has a high potential for energy use in biorefinery processes due to its thermochemical characteristics. However, it is necessary to carry out more precise analyzes to base the results obtained in relation to chemical and energy fractions in order to obtain greater efficiency and yield.

Keywords: Integral use. Potential energy. Chemical characterization. Biorefinery.