Propriedades da madeira de espécies do Cerrado Mineiro e sua potencialidade para geração de energia

Abstract

There is a great demand for charcoal to supply steel industry and a large amount of the charcoal produced is from native wood from a wide area of Cerrado. The government established a dateline until 2013 for the industries to stop buying charcoal from native forests. Therefore, the industry will be only able to natural resource through sustainable management plan to keep their wood supply for charcoal production. In order to achieve this goal, it is necessary to provide scientific research involving native species, to obtain information about available forest resources and their sustainable use. Therefore, the aim of this work was to determine chemical, physical and thermal properties of five species from Cerrado Mineiro and to evaluate their potential for energy generation. The species studied were Luehea divaricata, Casearia sylvestris, Guazuma ulmifolia, Rapanea ferruginea and Trema micrantha. Four trees of each species were sample from which 75 cm small logs were obtained. The logs were cutted into discs which were divided in four pars of opposed wedges. Analysis for determination of the basic density were made, basic density, lignin, extractives and ash contents were determined in the several samples, thermal analysis (TG, DTA and DSC) of wood. The material was carbonized after what proximate analysis of charcoal, elemental analysis (CHNSO) and heating value of the wood and charcoal were made. Casearia sylvestris was the species which presented the best characteristics for production and quality of charcoal since it presented high basic density, lignin content, thermal stability, charcoal yield, carbon content and heating value of wood. Although Trema micrantha had low basic density, it presented high fixed carbon content and generated charcoal with greater heating value. Rapanea ferruginea presented the lowest lignin and extractives contents and lower charcoal yield. Wood from Guazuma ulmifolia species had the highest extractive content, lowest ash content and high thermal stability. The species which presented charcoal with lowest heating value was Luehea divaricata, which stood out in thermal stability in the temperature range from 200 to 380º C, presenting the lowest mass losses in these temperatures.