Qualidade do carvão de resíduos florestais produzido em forno metálico com injeção de gases quentes para uso industrial

Abstract

Metal furnaces have been improved to improve traditional methods of charcoal production, aiming to reduce carbonization time, increase yields and optimize the use of by-products. The research aimed to evaluate the conversion of exploration residues generated in forest management and the quantitative and qualitative characteristics of charcoal produced in a prototype metal furnace, produced at the Charcoal Production Unit of Fazenda Rio Capim, belonging to the KEILLA Group, in the municipality of Paragominas-PA. To measure the density variations of the studied residues, wood with different densities (low, medium, high) was collected, preparing ten test specimens for each of these classifications, totaling thirty test specimens per batch. Five carbonizations were carried out with residues with different species inside the furnace. The samples of charcoal produced were sent to the Laboratory of Forest Products Technology - LTPF/ICA/UFRA for qualitative analyses, referring to the physical characteristics, (moisture, basic density and bulk density); chemical (volatile content, ash, fixed carbon), energetic (higher, lower and useful calorific value) and mechanical (friability) properties of the coal. The moisture content of the charcoal ranged from 4.29% to 5.07%. The apparent density was 0.330 g/cm³ (low density), 0.507 g/cm³ (medium) and 0.686 g/cm³ (high). The volatile material content (TMV) was between 27.42% and 28.29%, while the ash content (TCi) was higher in medium density charcoals (1.62%), followed by low (1.59%) and high density (1.40%). The fixed carbon content (TCF) was similar between the groups around 70%. The gross calorific value (SVC) varied little, with averages between 29,257.72 kJ/kg and 29,339.26 kJ/kg. The gravimetric yield was 31.2%, the volumetric yield was 37.6%, and the volumetric and gravimetric conversions were 1.441 m³/mdc and 3.2 t/t, respectively. The results presented are consistent with other studies found in relevant literature. The charcoal produced in a metal furnace with hot gas injection indicated that the physical characteristics concerning moisture content and wood density significantly influenced carbonization. The metal furnace technology made the distribution of energy inside the furnace more efficient, reducing carbonization time.