A madeira do gênero Pinus é amplamente utilizada na indústria florestal, principalmente no setor moveleiro e civil, sendo assim, importante a busca por técnicas que melhorem e aperfeiçoem as suas propriedades tecnológicas. Neste sentido, o presente estudo teve como objetivo avaliar o efeito da modificação térmica nas propriedades físicas da madeira de Pinus caribaea var. hondurensis sob duas diferentes temperaturas. Foram utilizadas três árvores com idade de 14 anos do campo experimental da Universidade Estadual do Sudoeste da Bahia, em Vitória da Conquista, BA, das quais foram confeccionadas em amostras com dimensões de 30 x 30 x 50 mm. O processo de modificação térmica foi realizado em uma estufa laboratorial a 160ºC e 200°C de temperatura final de ciclo que, somados ao controle, representaram três tratamentos em análise. Foram realizados os ensaios de densidade aparente, umidade, perda de massa, taxa de absorção de água e estabilidade dimensional. Concluiu-se que a modificação térmica alterou as propriedades físicas avaliadas, tornando a madeira menos higroscópica e com maior estabilidade dimensional, além de ter influenciado na coloração da madeira em relação a sua aparência natural.
The objective of this study was to evaluate the energy potential of Astronium fraxinifolium and Enterolobium gummiferum wood species that grow in the Savannah of Minas Gerais, Brazil, focusing on the production of charcoal. Two discs were removed at 1.30 m from the ground of three trees of each species, and these were later sampled into wedges that were applied in the analysis of wood characteristics and charcoal production in a muffle furnace. The extractives content and basic density of the wood species were determined, and apparent density of charcoal, ash content, heating value, and energy density of both materials were also determined. The woods under study have potential for application in energy production. Emphasis was placed on A. fraxinifolium, which presented wood and charcoal that was denser, had higher energy density, and achieved greater gravimetric yield.
Objetivo: o objetivo desta pesquisa foi determinar as características físicas, químicas e energéticas da madeira e do carvão vegetal da espécie Prosopis juliflora, utilizada em indústrias de cerâmicas vermelhas da região semiárida. Métodos: Foi utilizada a madeira de algaroba (Prosopis juliflora), espécie exótica, presente na região semiárida e com elevado uso para fins energéticos nas cerâmicas da região. O material coletado foi obtido em uma cerâmica localizada no município de Santa Luzia, Paraíba, Brasil. Foi determinada a densidade básica, composição química (extrativos, lignina e holocelulose), química imediata (materiais voláteis, carbono fixo e cinzas) e poder calorífico da madeira. E após o processo de pirólise da madeira, foi determinada o rendimento gravimétrico, densidade aparente, química imediata e poder calorífico do carvão vegetal. Resultados: Tanto a madeira quanto o carvão vegetal da espécie de P. juliflora apresentam características favoráveis para fins energéticos. Com alta densidade energética e poder calorífico, maior percentual de materiais voláteis e ligninas, e baixo de cinzas na madeira, e maior rendimento gravimétrico em carvão vegetal. Conclusão: Assim, P. juliflora possuí potencial para industria de cerâmica vermelha, contudo, recomenda-se a utilização da espécie em forma de madeira (lenha), por ser um método economicamente mais viável.
This paper aimed to evaluate the quality of wood and charcoal of Astronium fraxinifolium and Enterolobium gummiferum from Brazilian savannas (Cerrado). Discs from three trees of each species were removed at a height of 1.30 m above ground level. The samples were prepared for the analysis of the energy density and chemical components of the wood and for the production of charcoal at two final carbonization temperatures (350 and 450 ºC). After characterizing the charcoal, the carbonization yield and charcoal productivity per unit of wood volume were calculated. The wood of native species had potential for energy purposes. E. gummiferum charcoal stood out for its low ash content, and A. fraxinifolium wood presented higher apparent density and, consequently, higher carbonization yield and charcoal productivity per unit of wood volume. Charcoals produced at the two final carbonization temperatures presented adequate parameters for the steel industry and domestic use. The final temperature of 350 ºC is indicated as it presents higher gravimetric yield and energy yield of carbonization.
The objective of this study was to qualify the wood of the species Astronium fraxinifolium, Enterolobium gummiferum, Eriotheca pentaphylla, and Plathymenia reticulata of the Brazilian Cerrado for forestry productive purposes based on the classification of their wood basic density and fiber quality indices. Discs were removed at a height of 1.3 m from the ground, and opposing wedges were obtained. The analyzed parameters were: wood basic density, fiber dimension, and fiber quality indices. The wood basic density was negatively correlated with fiber length and thickness. E. pentaphylla presented low basic density, long fiber length, and greater fiber wall thickness. On the other hand, A. fraxinifolium, E. gummiferum, and P. reticulata woods presented medium/high basic density, short fiber length, and quality indices that foster them for energy purposes, paper production, and use in floors and civil construction.
This study evaluated Parkia gigantocarpa wood from the Amazon rainforest for its permeability to air and liquid in the longitudinal direction. The influence of anatomical characteristics on the permeability of wood was characterized. Three trees were collected in the State of Pará, Brazil. Samples were converted into specimens and subjected to permeability tests and anatomical characterization. Permeability was obtained in the laboratory, and the results were compared with the permeability data estimated by a longitudinal flow model for hardwoods. The air permeability of wood was 140.2 x 10-9 m3.[m.(N.m-2).s]-1 liquid permeability was 3.28 x 10-9 m3.[m.(N.m-2).s]-1. The fiber length and thickness of the cell wall had a direct and positive relationship with the permeability, whereas fiber width presented an inverse relationship with permeability. The vessel frequency and diameter did not influence the permeability of wood from the heartwood of P. gigantocarpa that presented high permeability and potential for easy wood drying and treatment.
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