Produção de briquetes de resíduo de madeira de eucalipto de agroindústrias

Abstract

The system of renewable energy generation by boilers is widely used in industries and in electric power plants, presenting significant consumption worldwide. In this process, biomass is consumed, generating waste without often having an appropriate place for disposal. This study aimed to analyze the reuse of waste from eucalyptus wood resulted from burning in a fluidized bed boiler of an agroindustry, which produces an average of 4,800 tons of waste per year. The waste generated is not going to an ecologically correct location, been often accumulated in some agroindustry company yard and crop soils. Waste physical and chemical properties, such as X-ray fluorescence (XRF) and X-ray diffraction (XRD), were analyzed for their crystalline structure to be transformed into dense, resistant, and durable blocks (briquettes) and to be reused in ovens and boilers. Thermogravimetric (TG) of the samples was also analyzed, evaluating the waste chemical decomposition. The residue was dried in an oven; some samples were pressed in a universal press and others in a manual press to manufacture the briquettes. It was needed to adjust the material moisture content when pressing, so that the briquette could be formed. Humidity of 50% was added to the briquettes made in the universal press, applying pressures of 3.41 MPa, 5.10 MPa, 12.31 MPa, and 37.50 MPa; 74% humidity was added for the briquettes made in the manual press, applying pressure of 0.38 MPa. After the pressing process, the tests of apparent density, durability, and firing were carried out. With the results found, it was possible to evaluate the briquette density and pressure; the briquette that received pressure of 0.38 MPa had a lower density and the one that received pressure of 37.50 MPa had a higher density. Regarding durability, the briquette with 37.50 MPa showed 92.4% efficiency in relation to the other briquettes, with a mass loss in the test of 7.6%. The analysis results on the physical-chemical characteristics together with the thermal properties of the briquettes showed that the main element present in the residue decomposition is CaCO3 (calcium carbonate); it was also possible to verify that the organic matter is available in great quantity in the residue, thus favoring the burning of the briquette. In conclusion, the produced briquettes are suitable for burning in boilers and ovens, in addition to being resistant for transport and storage.