Thiago de Paula Protásio

Quality and energetic evaluation of the charcoal made of babassu nut residues used in the steel industry

Brazil is the only country in the world that uses large scale charcoal in steel-making blast furnaces. Meantime, the monoculture plantations of Eucalyptus are not able to meet the demand for charcoal from the steel industries.Therefore, research is necessary, in order to use lignocellulosic residues for the production of charcoal with technological properties which are suitable for the reduction of iron ore. Given the above, the objective of this study was to evaluate the quality of charcoal which was made with babassu nut shell and designed for utilization in the steel industry in the function of the final carbonization temperature. All three layers of babassu nut shell (epicarp, mesocarp and endocarp) were used together. The initial temperature of the test was 100oC and the final temperatures were: 450oC, 550oC, 650oC, 750oC and 850oC. For the charcoals produced, the following properties were determined: apparent relative density, energy density and fixed carbon stock, in addition to chemical compositions (immediate and elemental) and heating values (higher and lower). Charcoal made of babassu nut shell showed high values of apparent density and energy density, and has a potential to replace coal and wood charcoal in the steel industry. The effect of the final carbonization temperature was expressed for all characteristics evaluated, except for the nitrogen content. Babassu nut shell must be carbonized at temperatures higher than 550oC, so that the charcoal produced can be used in steel-making blast furnaces.

THERMAL STABILITY OF Pinus oocarpa AND MAIZE COB PARTICLEBOARDS

Agricultural waste materials are generated in large quantities in Brazil. These can accumulate and cause serious environmental problems. One of the most commonly generated wastes in the brazilian agricultural culture is the maize cob. Being lignocellulosic in nature, the maize cob can find use as the raw material in the production of particleboards mainly concerned with furniture making. Therefore, studies regarding its thermal stability and fire resistance would be interesting. The aim of this study was to evaluate the combustibility and thermal stability of the particleboards produced from maize cob and Pinus oocarpa wood. The percentages in which maize cob was associated with Pinus oocarpa were 0%, 25%, 50%, 75% and 100%. The panels were produced using 8% urea-formaldehyde and 1% paraffin. The pressing cycle parameters included: temperature 150 °C, pressure of 3.92 MPa during 10 min. The combustibility curve analysis showed that the panels containing 25% content of maize cob had higher resistance to combustion. In general, the thermal stability decreased as the wood substitution by maize cob increased.

Avaliação da qualidade da madeira de Coffea arabica L. como fonte de bioenergia

Objetivou-se, neste trabalho, avaliar, por meio da analise de componentes principais, a qualidade da madeira de Coffea arabica L. em diferentes variedades e sistemas de cultivo como fonte de bioenergia. Foram utilizadas madeiras provenientes de tres sistemas de cultivo (natural, convencional e orgânico) e de duas variedades distintas (Mundo Novo e Catuai), totalizando seis tratamentos. Foram quantificados os teores dos componentes elementares (C, H, N, S e O), de cinzas, lignina, extrativos totais e holocelulose, a densidade basica, o poder calorifico superior, o poder calorifico inferior, o poder calorifico superior e inferior volumetricos das madeiras analisadas. Foi realizada a analise estatistica multivariada de componentes principais. Os escores das componentes principais de interesse foram determinados como forma de dividir as madeiras em grupos. O grupo I foi composto pela madeira do cafeeiro orgânico Mundo Novo e natural Mundo Novo; o grupo II pelo orgânico Catuai, e o grupo III pelas madeiras dos cafeeiros convencional Mundo Novo, natural Catuai e convencional Catuai. Os residuos madeireiros da especie Coffea arabica L. apresentaram grande potencial para o uso energetico, com destaque para as madeiras provenientes do sistema de cultivo convencional e da variedade Catuai. As madeiras do grupo III se destacaram em decorrencia dos elevados valores de poder calorifico volumetrico, densidade basica, teor de lignina e poder calorifico superior. Entretanto, as madeiras desse grupo apresentaram elevado teor de nitrogenio.

Umidade de equilíbrio de painéis OSB de clones de Eucalyptus urophylla

Conduziu-se, este trabalho, com o objetivo de testar a eficiencia da equacao de Nelson na estimativa da umidade de equilibrio desse tipo de material e propor um modelo para a determinacao da umidade dos paineis em funcao da umidade relativa do ar, bem como avaliar os efeitos de algumas variaveis de processo na umidade de equilibrio de paineis OSB (Oriented Strand Board). Amostras com dimensoes de 25 x 25 mm foram colocadas em câmara de climatizacao, onde permaneceram a uma temperatura constante de 30oC e tiveram suas massas determinadas, quando estabilizadas nos teores de umidade relativa do ar de 40, 50, 60, 70, 80 e 90%. Pelos resultados obtidos, pode-se concluir que: a equacao de Nelson tem a tendencia de subestimar os valores de umidade do painel; o modelo polinomial ajustado com base apenas na umidade relativa do ar apresentou grande potencial de utilizacao; nao houve efeito das variaveis densidade do painel, densidade basica da madeira, tipo de colchao e temperatura de prensagem sobre os valores medios de umidade de equilibrio na dessorcao 1, adsorcao e dessorcao 2, apesar de comportamentos distintos terem sido observados para as isotermas dos tratamentos.

Evaluation of Physical Properties of Particleboard Produced from Sugarcane Leaves

The southwest region of the state of Goiás stands out for agriculture, especially the production of grain and sugarcane. This high agricultural production has a result of generation of agroindustrial waste and it has a high potential to be exploited for particleboard manufacturing. In this context, the objective of this study was to evaluate the use of sugarcane leaves in the production of particleboards, compared to eucalyptus panels, through the evaluation of their physical properties. Three panels were made with 100% sugarcane leaves, and three with eucalyptus wood were produced. They were produced with a nominal density of 0.60 g/cm3. 12% urea-formaldehyde adhesives were applied based on their resin solid content. The used pressing cycle was: pressure of 4.00 MPa, temperature of 180°C and time of 15 minutes. After production, the same properties were evaluated on their water absorption and thickness swelling after 2 and 24 hours of immersion. A randomized design was used, and the averages were compared by the Scott-Knott test at 5% significance. Based on these results, it can be seen that panels produced with sugarcane leaves exhibited higher values for physical properties than eucalyptus panels.Keywords: Thickness swelling, waste ,water absorption.