Análise comparativa entre vários métodos de quantificação de hemiceluloses da madeira de eucalipto

Pulp hemicelluloses can be extracted with NaOH and quantified by colorimetric and gravimetric techniques. However the most usual methods to measure eucalyptus pulp hemicelluloses have been through the pentosan method or through xylan analyses by GC or HPLC techniques. In this study a comparison was made between the more traditional methods and indirect method of NaOH 5% extraction followed by colorimetric analyses. It was observed that the content of NaOH 5% extract correlates very well with pulp xylan content and reasonably well with the pentosan content. It is concluded that the 5% NaOH solubility method can be used in replacement of the other two, since it is faster, simpler and less costly to carry out than the others

Effect of Genetic Material and Rotation on the Properties of Charcoal

This study aimed to evaluate chemical properties and yield of charcoal from two Eucalyptus urophylla clones considering the first and second rotation of the wood. The study was carried out with material from Arcelor Mittal Jequitinhonha, with a mean age of 61.5 months. The values of fixed carbon, volatile materials, ash content, higher calorific value, gravimetric yield, liquid yield and gas yield were determined. The data were analyzed statistically by Analysis of Variance (ANOVA) and significant differences were compared by the Tukey test (p <0.05). The results showed significant differences for the fixed carbon contents (67% and 70.5%) and volatile materials (32% and 29%) of clones AEC 0182 and AEC 0296, respectively. The analysis of the results showed that both the first and second rotation woods have satisfactory characteristics for charcoal production and are not influenced by the effect of the rotations

HYDROTHERMAL TREATMENT OF EUCALYPTUS GRANDIS WOOD

 Among the technological alternatives to improve the quality and use of eucalyptus wood is heat treatment, as the wood has some features that may limit its use, such as dimensional instability, high anisotropy, and heterogeneous coloring. This study is aimed at evaluating the effect of time of hydrothermal treatment on physical, chemical, and mechanical properties of solid wood of Eucalyptus grandis. We used three trees of E. grandis, selecting only the heartwood, and prepared test specimens with dimensions of 30cmx8cmx3cm (length, width, and thickness). The hydrothermal treatment was performed in a Parr reactor using three reaction times (5, 15, and 25min) at 140°C. Partial removal of extractives occurred, especially in the outer layer of wood. There was an increase of up to 58% of its permeability because of the partial clearing of the vessel elements. There was no degradation of the main constituents of the wood, so loss of mechanical strength was observed. The hydrothermal treatment promoted the partial removal of the hydroxyl groups and/or a structural rearrangement of the hemicelluloses and cellulose, causing a reduction of the hygroscopicity of E. grandis.

EFFECT OF AGE ON HEARTWOOD / SAPWOOD RELATIONSHIP, EXTRACTIVE CONTENTE, AND PERMEABILITY OF TEAK WOOD

Due to the physiological differences in the juvenile and adult phases of teak wood, differentiation occurs in the impregnation by extractive materials along the heartwood regions, assuming that there is also a significant variation in the permeability of this material. Thus, the study aimed to evaluate the influence of age on the heartwood / sapwood ratio (H/S), permeability, and extractives content of Tectona grandis L.f wood. Four ages (10, 12, 14, and 16 years) and four trees (repetitions) were evaluated, totaling 16 samples. The H/S ratio, extractive content, and wood permeability were determined, in addition to the average and maximum permeability among all ages selected for calculation of their porosity. The H/S ratio increased over the ages of 10 and 16, and the content of extractive materials increased until the age of 14. There was a high heterogeneity between the permeability values of the wood at all ages analyzed, and one of the possible explanations for this fact is the presence of tyloses in different places on the trunk and the arrangement of the pores around the growth rings

Quality of Wood and Charcoal from Eucalyptus

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

EFEITO DA CARBONIZAÇÃO DA MADEIRA NA ESTRUTURA ANATÔMICA E DENSIDADE DO CARVÃO VEGETAL DE Eucalyptus

This study aimed to evaluate the anatomical changes that occur with charred wood and determine the anatomical properties, basic wood density and apparent density of charcoal Eucalyptus clones, besides elucidating the possible existing significant correlations. The scanning electron microscopy was performed in the transverse, longitudinal and tangential longitudinal and radial wood charcoal sections. In the morphological analysis of the pores and the apparent density was made. In general, the anatomical features such as pore radius and the wood fibers showed little or no change due to carbonization of coal surface and showed well defined structures. The changes in cellular elements of wood were mainly related to the quantitative parameters such as wall thickness and pore diameter fibers. The clones showed satisfactory basic density of wood for charcoal production. The anatomical parameters were significantly correlated with basic wood density and apparent density of charcoal, especially, in this study, the fraction of the fiber wall.O presente trabalho objetivou avaliar as modificações anatômicas que ocorrem com a carbonização da madeira e determinar as propriedades anatômicas, densidade básica da madeira e densidade aparente do carvão vegetal de clones de Eucalyptus, além de elucidar as possíveis correlações significativas existentes. A microscopia eletrônica de varredura foi efetuada nas seções transversal, longitudinal tangencial e longitudinal radial da madeira e do carvão vegetal. Neste, foi feita a análise morfológica dos poros e densidade aparente. De uma forma geral, as características anatômicas como forma de poros, raios e fibras da madeira apresentaram pouca ou nenhuma modificação devido à carbonização, e a superfície do carvão apresentou estruturas bem definidas. As modificações nos elementos celulares da madeira foram principalmente referentes aos parâmetros quantitativos, como espessura da parede das fibras e diâmetro dos poros. Os clones avaliados apresentaram densidade básica da madeira satisfatória para a produção de carvão vegetal. Os parâmetros anatômicos correlacionaram-se significativamente com a densidade básica da madeira e densidade aparente do carvão vegetal, destacando-se, neste estudo, a fração parede das fibras

Influence of adding kraft lignin in eucalyptus pellets properties

The pellets are becoming an important renewable source of energy for industrial and domestic use. The consumer market is increasingly demanding in terms of product quality and this may be improved through the use of various additives, such as kraft lignin. The objective of this study was to evaluate the quality of eucalyptus pellets produced with the addition of different percentages of kraft lignin. The raw material used for production of pellets was wood with bark of an Eucalyptus grandis x E. urophylla clone, with approximately five years of age, obtained from commercial planting, and 10% of waste of eucalyptus harvest (tops, leaves and branches). Excluding the control (0% lignin) was added 1, 2, 3, and 5% kraft lignin, relative to the dry mass of raw material. The pellets were produced in a laboratory pelletizer with a horizontal circular array. The following properties of the pellets were evaluated: moisture content, gross and net calorific value, unit density, bulk density, energy density, ash content, length and diameter, hardness, mechanical durability and fines content. The addition of kraft lignin contributed to improving the pellets physical and mechanical properties, as regards the density, mechanical durability, fines and hardness. The addition of lignin caused the elevation of the levels of ash and moisture content of the pellets. It is concluded that addition of lignin to pellet production is feasible, since lignin is used with lower contents of ash and moisture.Os pellets vêm se tornando uma importante fonte renovável de energia para utilização industrial e doméstica. O mercado consumidor está cada vez mais exigente quanto à qualidade do produto e essa pode ser melhorada por meio da utilização de diferentes aditivos, como a lignina kraft. Assim, o objetivo desse trabalho foi avaliar a qualidade dos pellets de eucalipto produzidos com adição de diferentes percentagens de lignina kraft. A matéria-prima utilizada para produção de pellets foi madeira com casca de um clone de Eucalyptus grandis x Eucalyptus urophylla com aproximadamente cinco anos de idade, proveniente de plantio comercial, além de 10% de resíduos da colheita do eucalipto (ponteira, folhas e galhos). Excluindo-se a testemunha (0% de lignina), adicionou-se 1, 2, 3, e 5% de lignina kraft, em relação à massa seca da matéria-prima. Os pellets foram produzidos em uma peletizadora laboratorial com matriz circular horizontal. Foram avaliadas as seguintes propriedades dos pellets: teor de umidade, poder calorífico superior e útil, densidade a granel e aparente, densidade energética, teor de cinzas, comprimento e diâmetro, dureza, durabilidade mecânica e teor de finos. A adição de lignina kraft em pellets de eucalipto contribuiu para a melhoria das propriedades físicas e mecânicas, no que se diz respeito à densidade, durabilidade mecânica, geração de finos e dureza. A adição de lignina ocasionou a elevação dos teores de cinzas e da umidade dos pellets. Conclui-se que a adição de lignina para produção de pellets é viável, desde que sejam utilizadas ligninas com menores teores de cinzas e umidade

AVALIAÇÃO DE DIFERENTES NÍVEIS DE DESBASTE NAS PROPRIEDADES DA MADEIRA E DO CARVÃO VEGETAL DE Eucalyptus grandis x Eucalyptus urophylla

O presente trabalho teve como objetivo avaliar os efeitos de diferentes níveis de desbaste nas propriedades físicas e químicas da madeira e do carvão vegetal de híbrido de Eucalyptus urophylla W. Hill ex Maiden x Eucalyptus grandis S. T. Blake. O experimento foi instalado em um talhão de uma empresa do setor florestal, que foi dividido em quatro faixas, representando os níveis de desbaste de 0, 20, 35 e 50% aplicados ao povoamento aos cinco anos. Foram coletadas 3 árvores de cada tratamento, 62 meses pós-desbaste. Determinou-se densidade básica, poder calorífico superior (PCS) e composição química da madeira, os rendimentos gravimétricos além da densidade aparente, PCS e composição química imediata do carvão vegetal. A madeira apresentou características tecnológicas satisfatórias para produção de carvão vegetal, sob os diferentes níveis de desbaste, porém estes não influenciaram de maneira significativa as propriedades físicas e químicas doccarvão vegetal.This research aimed to evaluate effects of different levels of thinning in the physical and chemical properties of wood and charcoal from a hybrid clone of Eucalyptus urophylla W. Hill ex Maiden x Eucalyptus grandis S. T. Blake. The experiment was conducted in a plot of a forestry company which was divided into four tracks, representing the thinning levels of 0, 20, 35 and 50% applied to five years old plantations. Three trees were collected from each treatment, 62 months after thinning. Basic density, calorific power and chemical composition of wood had been determined, as well as charcoal properties as follows: gravimetric yields, density, chemical immediate composition and calorific power. Wood presented suitable technological characteristics for charcoal production, under different levels of thinning, but these did not influence significantly charcoal physical and chemical properties

Agrupamento de espécies madeireiras da Amazônia com base em propriedades físicas e mecânicas

The intense search for consolidated native wood essences, which are highly used, can lead to the overexploitation of species and decrease their stocks in the forest. An alternative to this situation is the replacement of these species by others with similar wood properties and with sufficient forest growing stock. The objective of this work was to cluster the Amazon species through wood physical-mechanical properties and perform the discriminant analysis to identify which technological characteristics are more important for the clustering. The species studied came from eight different locations in the Amazon region. The properties used were: basic density, contraction (tangential, radial and volumetric), static flexion, compression parallel and perpendicular to the fibers, Janka hardness parallel and transversal, traction perpendicular to the fibers, cracking and shearing, all obtained from the national specialized literature. Multivariate Cluster analysis (simple Euclidean distance and Ward’s method) and the discriminant analyses were used to evaluate the clustering. Cluster analysis was efficient to cluster the species, which were separated into three distinct groups. The species that stood out were Helicostylis pedunculata Benoist. and Tachigali chrysophylla (Poepp.) Zarucchi & Herend., f or clustering with the most commercialized species. The lowest values of Wilks’Lambda were wood density (0.759053), shearing (0.802960) and compression parallel to the fibers (0.825594). These characteristics were the most determinant to discriminate the clusters. The clustering analysis was efficient for the separation of the species into marketing clustersA procura intensa por essências madeireiras nativas consolidadas, que apresentam elevado uso, pode ocasionar a superexploração de espécies e diminuição do seu estoque na floresta. Uma alternativa para essa situação é a substituição dessas espécies por outras com propriedades da madeira semelhantes e com suficiente estoque de crescimento na floresta. O objetivo deste trabalho foi agrupar as espécies da Amazônia através das propriedades físico-mecânicas da madeira e realizar a análise discriminante para identificar quais características tecnológicas são mais importantes para o agrupamento. As espécies estudadas foram provenientes de oito localidades distintas da região amazônica. As propriedades físico-mecânicas utilizadas obtidas da literatura especializada nacional foram: densidade básica, contração (tangencial, radial e volumétrica), flexão estática, compressão paralela e perpendicular às fibras, dureza Janka paralela e transversal, tração perpendicular às fibras, fendilhamento e cisalhamento. Foi utilizada a técnica de análise multivariada de Cluster (distância euclidiana simples e o método de Ward) e a análise discriminante para avaliar o agrupamento. A análise de Cluster foi eficiente para agrupar as espécies, que foram separadas em três grupos distintos. As espécies que se destacaram foram a Helicostylis pedunculata Benoist. e Tachigali chrysophylla (Poepp.) Zarucchi & Herend., por se agruparem com as espécies mais comercializadas. Os menores valores de Wilks’Lambda foram da densidade da madeira (0,759053), cisalhamento (0,802960) e compressão paralela às fibras (0,825594). Essas características foram as mais determinantes para discriminar os grupos. A análise de agrupamento é eficiente para indicar a substituição de espécies consolidadas na Amazônia

Propriedades físicas e mecânicas de papéis reciclados utilizados para fabricação de tubetes

http://dx.doi.org/10.5902/198050985748OThe present study investigated, through laboratory testing, the physical and mechanical properties of recycled paper used to produce tubes. To do so, we used six types of paper with a weight average of 400 g / m² and once the laboratory tests followed the procedures of the Technical Association of Pulp and Paper Industry. There was significant difference between the roles studied in terms of physical and mechanical characteristics, and the paper type A1 had, in general, the best results, justifying its high price in the market. The A3 has the highest density, the data relevant to industry tubes, since these are usually sold by weight. It is concluded that all of the studied papers are suitable for tube production, being used in accordance with the customer's demands, since the price of the paper is what determines, most of the time, the tube value.http://dx.doi.org/10.5902/198050985748OPresente trabalho objetivou estudar, através de ensaios laboratoriais, as propriedades físicas e mecânicas de papéis reciclados utilizados para produção de tubetes. Para tanto se utilizou seis tipos de papéis com gramatura média de 400 g/m² e para os ensaios de laboratório seguiu-se os procedimentos da Technical Association of Pulp and Paper Industry. Verificou-se diferença significativa entre os papéis estudados quanto às características físicas e mecânicas, sendo que o papel Tipo A1 obteve, de modo geral, os melhores resultados, justificando seu alto preço no mercado. O papel A3 foi o de maior densidade, dado relevante para indústria de tubetes, já que estes são geralmente comercializados por peso. Conclui-se que todos os papéis estudados são indicados para produção de tubetes, devendo ser utilizados de acordo com as exigências do cliente, visto que o preço do papel é que determina, na maioria das vezes, o valor do tubete