Quality and energetic evaluation of the charcoal made of babassu nut residues used in the steel industry

Abstract

Brazil is the only country in the world that uses large scale charcoal in steel-making blast furnaces. Meantime, the monoculture plantations of Eucalyptus are not able to meet the demand for charcoal from the steel industries.Therefore, research is necessary, in order to use lignocellulosic residues for the production of charcoal with technological properties which are suitable for the reduction of iron ore. Given the above, the objective of this study was to evaluate the quality of charcoal which was made with babassu nut shell and designed for utilization in the steel industry in the function of the final carbonization temperature. All three layers of babassu nut shell (epicarp, mesocarp and endocarp) were used together. The initial temperature of the test was 100ºC and the final temperatures were: 450ºC, 550ºC, 650ºC, 750ºC and 850ºC. For the charcoals produced, the following properties were determined: apparent relative density, energy density and fixed carbon stock, in addition to chemical compositions (immediate and elemental) and heating values (higher and lower). Charcoal made of babassu nut shell showed high values of apparent density and energy density, and has a potential to replace coal and wood charcoal in the steel industry. The effect of the final carbonization temperature was expressed for all characteristics evaluated, except for the nitrogen content. Babassu nut shell must be carbonized at temperatures higher than 550ºC, so that the charcoal produced can be used in steel-making blast furnaces.