Benedito Rocha Vital

Estrutura anatômica da madeira e qualidade do carvão de Mimosa tenuiflora (Willd.) Poir

The objective of this work was to determine anatomical characteristics, and dimensions of fibers, vessels and parenchyma and ray cells of Mimosa tenuiflora (Willd.) Poir wood. Fibers wall fraction, the percentage of fibers, vessels and ray and parenchyma cells, as well as density and charcoal production and properties were determined. The wood of Mimosa teniflora presents predominantly solitary, geminated and multiple porous in radial groups; porous distributed in uniform diffuse porosity; axial parenchyma paratracheal vasicentric, confluent vasicentric, aliform and confluent aliform; multiseriate, biseiat rays and, less frequently, uniseriate ones; very short fibers with thick walls. Charcoal yield was 39.68% with a 0.51g/cm3 density, 71.79% carbon content and 6886cal/g calorific value.

Quality of Wood and Charcoal from Eucalyptus Clones for Ironmaster Use

Considering the wide variety of species and clones of Eucalyptus cultivated in Brazil, it is necessary to search for new information on wood properties, so that the selection of genetically superior material may be successful. The present study aimed to determine the properties of wood and charcoal from different clones of Eucalyptus spp. Six clones at the age of 7.5 years were evaluated and the samples were from a clonal, located in the city of Lassance, Minas Gerais, Brazil. Basic density, chemical composition, and higher heating value were determined. Carbonizations in a laboratory kiln were done and the levels of volatile matter, ash, and fixed carbon, higher heating value, and bulk density of the charcoal produced were determined. Evaluated genetic materials showed differences in their properties. According to research results, several properties of wood should be considered together for the selection of clones for charcoal production. However, basic density and chemical composition of wood, especially high contents of lignin and low contents of extractives, are the properties that had more influence on charcoal yield and its quality. Concerning charcoal production for steelmaking, clone 6 stood out and, conversely, clone 4 showed inferior properties to those of others.

Avaliação de algumas propriedades da madeira de Eucalyptus grandis, Eucalyptus saligna e Pinus elliottii

This work aimed to determine sawn wood yield, as well as density, volumetric shrinkage, static bending and compression parallel to grain strength, glue line quality and machining for Eucalyptus grandis, Eucalyptus saligna and Pinus elliottii wood. Three trees of each species, with approximate ages of 50, 40 and 40 years, respectively, were cut into logs on the base, middle and top. Property variations were analyzed in the pith-bark and longitudinal directions. The results showed that all the physical and mechanical properties varied inside the tree in the radial and longitudinal directions. Basic density, bending and compression strength increased in the pith-bark direction, while volumetric shrinkage decreased. Therefore, for obtaining denser, more stable wood with larger bending and compression strength it is necessary to harvest older trees. Considering the variations in the longitudinal direction, it was observed that logs from the medium portion of the tree presented smaller values than those from the base and from the top, in all the analyzed properties. Glue line strength and wood failure presented little differences in relation to adherence among juvenile wood and mature wood in all the positions. In the and mortise-and-tenon test, all the species showed satisfactory results, without occurrence of defects.

QUALIDADE DA MADEIRA EM CLONE DE Eucalyptus grandis W. Hill ex Maiden SUBMETIDO A DESRAMA ARTIFICIAL

n The present study aimed at the evaluation of the influence of artificial pruning of Eucalyptus grandis Hill ex Maiden clones on wood quality for sawnboard production, in Southeastern Brazil. Branches were removed to different heights from the ground and number of interventions to reach a 6†m branch-free trunk, with the first pruning intervention starting at the age of 16 months. By the age of 55 months, no significant differences (p>.05) were found for taper, flatness and bow of the first 3†m log as a result of pruning. The clear wood production of the pruning treatments was, on average, 94†% greater than the control. Clear wood production increased with the reduction in the diameter over occlusion (wood knotty core). The pruning wounds smaller than 1.5†cm in diameter showed 0.48 cm stub occlusion extension and the wounds larger than 1.5†cm showed 0.74 cm stub occlusion extension. The branch angle was larger for the thinner branches and had no correlation with pruning. Wood density along the trunk was not affected by artificial pruning, however, it decreased from the top to the base of the first log and increased from pith to bark. The overall results indicate mainly that the genetic material for sawnboard production must present smal diameter branches and pruning must be carried out as early as possible to attain larger clear wood extension.

Propriedades energéticas da madeira e do carvão de paricá (Schizolobium amazonicum)

The objective of this study was to evaluate the energy potential of wood and coal of Schizolobium amazonicum (parica). The trees were collected in the region of Dom Eliseu - PA, at ages 5, 7, 9 and 11 years and sectioned in four logs of 2.7 m each. By using the thermogravimetric analysis of wood, mass loss as a function of temperature was determined. The higher calorific value was obtained according to NBR- 8633 standard. Gravimetric yield in coal and its chemical composition were also determined. There was significant effect of age and height in the log only at the temperature range from 300 to 400oC. The wood calorific value was influenced by the age of trees and the highest value was observed at the age of 5 years. The gravimetric yield and chemical composition of charcoal were not affected by the age of the trees.

Avaliação de duas rotinas de carbonização em fornos retangulares

RESUMO – Este estudo objetivou avaliar o desempenho de fornos retangulares no processo de carbonizacao, envolvendo duas rotinas de carbonizacao. As rotinas analisaram a influencia de tatus e câmaras de combustao externa no processo de carbonizacao em quatro fornos retangulares instrumentados com termopares para acompanhamento da temperatura, bem como o balanco de massa e energia do sistema. A lenha utilizada na carbonizacao foi o clone A08, hibrido do cruzamento entre Eucalyptus grandis e Eucalyptus urophylla, com idade de 7 anos e comprimento da lenha de 3 m. Foram realizadas oito carbonizacoes em cada rotina. De acordo com os resultados, verificou-se que a rotina 2, caracterizada pelo uso das câmaras de combustao externa, foi mais eficiente no controle da carbonizacao; a instrumentacao do forno e uma tecnica viavel, mas que requer ajustes para caracterizar, com precisao, o fenomeno da carbonizacao. No balanco de massa e energia, verificou-se que as perdas foram maiores que os ganhos em producao, para lenha com elevados teores de umidade. Palavras-chave: Fornos retangulares, Carbonizacao de madeira e Producao de carvao vegetal. EVALUTION OF TWO CARBONIZATION ROUTINES IN RECTANGULAR KILNS

Potencial energético da madeira de Eucalyptus sp. em função da idade e de diferentes materiais genéticos

The present study aimed to determine the influence of age and different genetic material of Eucalyptus sp. in wood energy production. Therefore, we evaluated three Eucalyptus sp. clones from Gerdau S/A, at four different ages: 3, 4, 5 and 7 years. Five discs were removed from each tree (0%, 25%, 50%, 75%, 100% of the trunk commercial height), and the wood basic density and calorific value were determined. Based on these values we estimated the energy m-3 amount. We observed an effect of age and genetic material for the wood density and the calorific value. Moreover, the amount of energy m-3 increased with increasing age, and the three genetic materials evaluated were significantly different between them. The GG 680 clone showed better performance for this variable, presenting at seven years 2,943 kW.h.m -³ . Note that the selection of the best genetic material must consider the wood technological characteristics, as well as their productivity and effectiveness of technical production.

QUALIDADE DE JUNTAS COLADAS COM LMINAS DE MADEIRA ORIUNDAS DE TRS REGI'ES DO TRONCO DE Eucalyptus grandis, Eucalyptus saligna E Pinus elliottii 1

Este experimento teve como objetivo avaliar a resistencia de juntas coladas formadas pelas combinacoes de lâminas provenientes de tres posicoes no tronco da madeira de Eucalyptus grandis, Eucalyptus saligna e Pinus elliottii. Foram empregados adesivos a base de poliacetato de vinila de media e alta viscosidade e resorcinol-formaldeido nas gramaturas de 150 g/m2, em face simples para o poliacetato de vinila de media e alta viscosidades e 300 g/m2, em face dupla, para o adesivo resorcinolico. O teor medio de umidade das lâminas, no momento da colagem, foi igual a 14%. Os valores medios mais elevados de resistencia ao cisalhamento foram obtidos nas juntas produzidas com madeira de Eucalyptus saligna, coladas com adesivos de poliacetato de media viscosidade e resorcinol-formaldeido. A maior porcentagem de falha profunda na madeira foi obtida em juntas de madeira de Pinus elliottii, unidas com adesivo de poliacetato de alta viscosidade, seguidas das juntas de Eucalyptus grandis e coladas com adesivo de poliacetato de media viscosidade. As combinacoes de lâminas oriundas das seguintes posicoes no tronco: medula e casca, intermediaria e casca e casca e casca resultaram em linhas de cola com maiores resistencias ao cisalhamento.

Propriedades de chapas tipo OSB, fabricadas com partículas acetiladas de madeiras de Eucalyptus grandis, Eucalyptus urophylla, Eucalyptus cloeziana e Pinus elliottii

The objectives of this work was to evaluate the properties of OSB (Oriented Strand Board). Wood was collected from Eucalyptus grandis, Eucalyptus urophylla and Eucalyptus cloeziana on the municipalities of Ponte Alta and Tres Marias, in the state of Minas Gerais. Wood densities were respectively: Ponte Alta (0.55, 0.61 and 0.70g/cm³) and Tres Marias (0.56, 0.58 e 0.69g/cm³). Strands of Pinus elliottii, derived from the city of Vicosa, with density of 0.45g/cm³, were added to strands of eucalyptus when necessary to keep board densities close to 0.70g/cm³. Flakes were fabricated in a laboratory disk flaker measuring approximately 20.00 x 0.46 x 90.00 mm. Phenol-formaldehyde adhesive was applied at 8% solid rate, in relation to particle dry mass. Part of the treatment was carried out with flakes from acetylated eucalyptus. The boards were pressed at 170°C and 32 kgf/cm² pressure. Boards properties were determined according to the ABNT NBR 14810-3 (2002) and ASTM-D 1037 (1991) norms. The results were compared using the ANSI/A - 208.1 (1993) and CSA 0437-93 (1993) norms. OSB manufactured with any amount of acetylated flakes was more stable and absorbed less water. However the resistance to perpendicular traction of OSB with 100% of acetylated flakes was inferior to the stipulated by the CSA O437-0/93 (1993) norm. It was also found that acetylation had a negative effect on screw withdrawal resistance, module of rupture (parallel and perpendicular) and longitudinal compression resistance (perpendicular) of Eucalyptus grandis OSB having 100% of their flakes acetylated. Boards that presented numerically the highest means were manufactured with non-acetylated flakes of Eucalyptus grandis (Janka hardness) and Eucalyptus cloeziana mixed with Pinus sp (module of rupture). Only resistance to longitudinal compression was affected by the wood origin. OSB manufactured with Eucalyptus urophylla wood, from the Cerrado, had lower means than OSB made of the same species, however, from Vale do Rio Doce.

Otimização da produção do carvão vegetal por meio do controle de temperaturas de carbonização

Although in recent years several studies have been done with the aim of improving the wood quality indices (basic density, chemical composition), much of the Brazilian charcoal production still occurs in kilns that have low gravimetric yield and uncontrolled emissions of polluting gases. In an attempt to change this scenario, this work was developed with the objective of evaluating the operation of a kiln-furnace system. The work also aimed to adjust carbonization control ranges according to temperature and time, taking into account the thermal degradation of wood in order to maximize the yield of charcoal. Three kilns were built, attached to a furnace for burning the gases generated during the carbonization. Control of carbonization was conducted using internal temperature, measured by an infrared temperature sensor. According to the results, controlling time and temperature during the carbonization provided average gravimetric yields of 33% charcoal, 8% semi-carbonized wood and 3% fines (particle size less than 12.7 mm). The furnace was efficient in reducing fume to the environment, working for a third time carbonization. It is concluded that the kiln-furnace system presents satisfactory production of charcoal, with low fume during carbonization.