Hill ex Maiden; e determinar sua correlação com a densidade da madeira, visando a avaliar o potencial da colorimetria como uma ferramenta para a identificação e qualificação da madeira. As análises colorimétricas foram realizadas segundo o sistema CIE L*a*b* com o auxílio do espectrofotômetro portátil CM 2600d da Konica Minolta. Os resultados indicaram diferenças significativas entre as densidades das espécies estudadas, sendo a madeira de Eucalyptus paniculata a mais densa e a madeira de Eucalyptus grandis a menos densa. As análises de correlação entre a cor e a densidade monstraram que as madeiras mais densas, para as espécies do gênero Eucalyptus estudadas, são mais escuras (menor L*) e apresentam mais pigmento vermelho (a*) e amarelo (b*). Entretanto, o comportamento foi diferente para o Corymbia citriodora, cuja madeira apresentou alta densidade, cor clara e pouco pigmento vermelho, indicando que a combinação das variáveis colorimétricas e da densidade apresenta potencial para segregar a espécie Corymbia citriodora das demais espécies de Eucalyptus estudadas. As madeiras mais densas de Eucalyptus pellita são mais escuras na seção radial, enquanto que as madeiras de Eucalyptus paniculata apresentaram mais pigmento amarelo na seção tangencial. Cada espécie apresentou uma coloração específica, dada pelas variáveis colorimétricas, mostrando o potencial da colorimetria na identificação de madeiras COLORIMETRY OF WOODS FROM Eucalyptus AND Corymbia GENUS AND ITS CORRELATION WITH DENSITYABSTRACT: The objectives of this study were to characterize the wood color of Corymbia citriodora (Hook.) K.D. Hill & L.A.S. Johnson, Eucalyptus pellita F. Muell, Eucalyptus paniculata Sm. and Eucalyptus grandis Hill ex Maiden; and to determine its correlationship with wood density in order to evaluate the potential of colorimetry as a tool for identification and qualification of wood. Color analysis were performed on the CIE L*a*b* system by using the CM 2600d spectrophotometer from Konica Minolta. The results indicated significant differences between wood densities of all species. Eucalyptus paniculata wood presented the highest density while Eucalyptus grandis wood presented the lowest density. Correlation analysis between color and density showed that the denser woods, considering the species from the Eucalyptus genus studied, are darker (lower L*) and present redder (a*) and more yellow (b*) hues. However, the behavior was different for Corymbia citriodora, whose wood had high density, light color and little red hue, indicating that color variables and density combination has potential to segregate the Corymbia citriodora species from other Eucalyptus species studied. The denser woods of Eucalyptus pellita are darker in the radial section, while woods of Eucalyptus paniculata presented more yellow hue (b*) in the tangential section. Each species presented a specific color, given by colorimetric variables, showing the potential of colorimetry for wood identification.

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RESUMOO carvão vegetal é um produto de grande importância na economia brasileira, fato este ligado ao seu uso como fonte de energia renovável e redutor no setor siderúrgico. Esforços vêm sendo feitos visando à melhoria do processo de produção do carvão vegetal, o qual pode ser obtido em diferentes tipos de fornos, com rendimentos e qualidade variados. Dessa forma, o objetivo deste trabalho foi realizar o levantamento das características referentes à planta de carbonização pertencente à Saint Gobain Ltda. situada no município de Seropédica/RJ e analisar quimicamente o carvão produzido. Os dados foram obtidos por meio de questionário e comparados aos de outras duas empresas do mesmo segmento. A análise das amostras de carvão vegetal foi realizada em laboratório, através da análise química imediata. Os fornos utilizados na produção de carvão vegetal existentes na planta de carbonização da empresa analisada caracterizam-se como fornos de superfície com chaminé. O rendimento médio observado da conversão da madeira em carvão vegetal foi de 50%. Na comparação com outros sistemas de carbonização, a empresa analisada apresentou valores intermediários em termos de rendimento do processo e o carvão vegetal produzido foi considerado de boa qualidade, apresentando elevado teor de carbono fixo (82,70%) e baixo teor de cinza (1,30%).Palavras-chave: energias renováveis, siderurgia, madeira para energia. Case Study of a Carbonization Plant: Evaluation of Features and Quality of Charcoal Aiming Steel Use ABSTRACTCharcoal is a product of great importance in the Brazilian economy, a fact linked to its use as a renewable energy source and reducing the steel industry. Efforts have been made aiming at improving the production process of charcoal, which can be obtained in different furnace types with varying yield and quality. Taking these factors into consideration, the aim of this study was to survey the characteristics relating to the carbonization plant belonging to the Saint Gobain Ltda. company, in the city of Seropédica/Rio de Janeiro-Brazil and chemically analyze the coal produced. The data were obtained through a questionnaire and compared to the other two companies in the same industrial segment. The analysis of charcoal samples was conducted in the laboratory through chemical analysis. The furnaces used in charcoal production in existing carbonization plant analyzed company are characterized as surface furnaces with chimney. The average output of the conversion of wood charcoal was 50%. Compared to other carbonization systems, the company analyzed showed intermediate values in terms of process yield and charcoal produced is considered good quality, with high fixed carbon content (82.70%) and low ash content (1,30%).

During the thermal modification of the wood there is a decreasing gradient of temperature from the surface to its interior, therefore, the most severe chemical modifications occur on the surface. These chemical modifications directly affect the quality and durability of adhesives and coating. Therefore, this study investigated the chemical modification of the surface of thermally-modified teak juvenile wood. Heartwood and sapwood samples were treated at 180 and 200ºC. Chemical analyses were performed by Fourier transform infrared spectroscopy (FTIR) in reflectance mode with a microscope. Spectra showed an increase in cellulose crystallinity and a decrease in relative contents of hydroxyl groups, lignin and extractives-especially quinones, waxes and oils-following thermal modification. Extractive content of the heartwood was relatively higher than that of sapwood. Heartwood was more susceptible to thermal degradation than sapwood.

Wood pyrolysis has been use for centuries to obtain charcoal. Nonetheless, the study of wood components altering by the pyrolysis temperature is crucial to determine the charcoal’s properties. The present research aims to evaluate by FTIR the chemical altering of wood submitted to various pyrolysis temperatures. Sam-ples of Corymbia citriodora species were submitted to temperatures of 240 °C, 280 °C, 320 °C and 400 °C in a fixed bed reactor filled with N2. The FTIR analysis was performed in the wood residues after pyrolysis. The results showed that cellulose and hemicelluloses presented more susceptibility to thermal degradation than other wood components. It could be observed chemical altering in the wood residue obtained between 240 °C and 280 °C. In addition, the wood residue obtained for treatments over 280 °C presented characteristics simi-lar to vegetal charcoal. There are a continuous change of the wood due to the temperature of the pyrolysis by the change of bands intensity and by the bands shift. The FTIR analysis allowed the evaluation of the wood’s pyrolysis process and its chemical variations with the temperatures applicate.