Omnibus survey of pupils and their parents or carers: wave 5: Research report: March 2019

Brazilian productivity of eucalyptus trees is one of the highest in the world, and it has sustainable and viable conditions to supply the demand for woody biomass in a large quantity and diversity. This favorable situation makes Brazil one of the countries with the greatest potential for the production development of torrefied woody biomass on a commercial scale. Torrefaction is a mild pyrolysis applied to increase the energy quality of the feedstock. The aim of this study was to evaluate the Brazilian potential of woody biomass torrefaction for energy purposes. An experimental study was performed evaluating this thermal treatment of eucalyptus wood chips on a semi-continuous screw reactor developed by a Brazilian university. The results showed the increases in the energy quality of eucalyptus wood chips as a function of torrefaction temperature and time. This thermal treatment was technically feasible for the hygroscopicity reduction and the increases of fixed carbon and calorific values of the woody biomass

Método de ressonância para predição das propriedades mecânicas das madeiras de Eucalyptus urophylla e Pinus oocarpa termorretificadas

Vibrações transversais apresentam potencial para avaliação da madeira devido a alta precisão, baixo custo erapidez, mas sua aplicação em madeira termorretificada ainda é pouco estudada. O objetivo deste trabalho foiavaliar as propriedades físicas e mecânicas de madeira termorretificada de Eucalyptus urophylla e Pinus oocarpae relacionar a análise de ressonância (Bing) com o modulo de elasticidade estático e de ruptura da madeira.Corpos de prova foram confeccionados de três árvores de Eucalyptus urophylla e três de Pinus oocarpae termorretificados a 150, 175, 200 e 225°C, com taxa de aquecimento de 5°C/min, tempo de residência dequatro horas com pressão atmosférica e presença de ar.A termorretificação reduziu a densidade básica, inchamento volumétrico, inchamento linear, coeficiente deanisotropia, umidade de equilíbrio e resistência mecânica da madeira de ambas as espécies. A análise de ressonância(Bing) apresentou alta relação com o modulo de elasticidade estático e o módulo de ruptura da madeiratermorretificada de ambas as espécies e, portanto, esta técnica pode ser utilizada para avaliar as propriedadesmecânicas da madeira submetidas a este processo

Composição química da madeira de eucalipto com diferentes níveis de desbaste

http://dx.doi.org/10.5902/1980509812359The objective of this study was to evaluate different thinning regimes in forest plantations of eucalypt(Eucalyptus grandis x Eucalyptus urophylla) clones to produce timber for cellulose and charcoal to verifywhether this effect could affect the proportion of the chemical components of wood. The average initialspacing between plants was 3x3 m and the treatments were: T1= control, T2, T3and T4 with thinning 20%,35% and 50% of the basal area, respectively. The results were analyzed by Tukey test at 5% probability.According to the results found the lignin content from treatment T4 was higher than that of the others; thegroups of uronic acids of the T1 was similar to all other treatments, but the levels of T2 and T4 differedbetween them. The extractives content of T1was similar to the T2 and T3 and lower than that of theT4; thecarbohydrates of T1 were similar to that of T3 and higher than the others. It was concluded that thinningincreases the quality of the wood to be used as energy purposes, such as charcoal production, but it did notincrease productivity for wood pulp and paper production.http://dx.doi.org/10.5902/1980509812359O objetivo deste estudo foi avaliar diferentes regimes de desbaste em plantios silviculturais de clones de eucalipto (Eucalyptus urophylla x Eucalyptus grandis) para produção de madeira visando à obtenção de celulose e carvão com a finalidade de verificar se este efeito poderia afetar quantitativamente a proporção dos componentes químicos da madeira. O espaçamento inicial médio entre plantas foi de 3 x 3 m e os tratamentos foram: T1= testemunha, T2, T3 e T4 com desbaste de 20%, 35% e 50% da área basal presente, respectivamente. Os resultados foram submetidos ao teste de Tukey com 5% de probabilidade. De acordo com os resultados, constatou-se que o teor de lignina resultante do tratamento T4 foi maior que o dos demais; o de grupos urônicos do T1 foi semelhante ao dos demais tratamentos, mas os teores dos T2 e T4 diferiram entre si. O teor de extrativos do T1 foi semelhante ao dos T2 e T3 e menor que o do T4; o de carboidratos do T1 foi semelhante ao do T3 e superior aos demais. Concluiu-se que o desbaste aumenta a qualidade da madeira para ser utilizada como fins energéticos, como produção de carvão, mas não aumenta a produtividade de madeira destinada à confecção de celulose e papel

Effect of extractives on wood color of heat treated Pinus radiata and Eucalyptus pellita

Heat treatment can change wood color without any use of environmentally harmful chemicals, and the efficiency of this process depends on the raw material to be treated. The objective of this study was to evaluate the influence of extractives on the color change of Eucalyptus pellita and Pinus radiata wood during heat treatment. The extractives were extracted in cold water and in dichloromethane as well as totally removed and the wood was treated at 170°C and 200°C for three hours under atmospheric pressure and in presence of air for evaluating the lightness (L*), green-red coordinate (a*), blue-yellow coordinate (b*), color saturation (C) and tonality angle (H) values. Pinus radiata wood was more resistantto discoloration by heat treatment. The removal of total and cold water-soluble extractives before heat treatment changed the L* value of Pinus radiata, a* value of Eucalyptus pellita, and b*, C, and H valuesof both species. Removal of extractives soluble in dichloromethane did not affect the color of heat treated wood. Thus, understanding the influence of extractives on heat treated wood can allow adapting the raw material to the process for enhancing the applicability of heat treatment for changing wood color

Potencial energético de coprodutos gerados a partir da produção de biodiesel de pinhão manso (Jatropha curcas L.)

This study aimed to evaluate the energetic use potential of co-products from chain of Jatropha biodiesel production. For this, the higher heating value and immediate analysis (volatile matter, ash and fixed carbon content) were determined for epicarp samples (shell), cake from the press extraction process, and the bran from the solvent extraction process. Co-products of the biodiesel production chain from Jatropha under shells, cake, and bran form have energetic characteristics that make possible its use for energy production for used in different processes. The oil content has an effect on the calorific value of jatropha co-products. The higher the residual oil content in the pie or bran, the greater the energy potential. The peas, the pie and the bran presented calorific power similar to eucalyptus wood and sugarcane bagasse. The last one is widely used in cogeneration systems in the sugar-alcohol industry and can be used directly or compacted in the generation of heat for processes both in the processing industry and in the field. The pie (obtained by mechanical pressing) was the co-product that presented better conditions for direct burning when compared to the other evaluated materials.Objetivou-se com presente trabalho avaliar o potencial de aproveitamento energético de coprodutos da cadeia de produção de biodiesel de pinhão manso. Para isso, o poder calorífico superior (PCS) e a análise imediata (teor de materiais voláteis, de cinzas e de carbono fixo) foram determinados para amostras de epicarpo (casca), torta proveniente do processo de extração por prensagem e farelo proveniente do processo de extração com solvente. Os coprodutos da cadeia de produção de biodiesel de pinhão manso na forma de cascas, torta e farelo apresentam características energéticas que torna possível o seu aproveitamento para a produção de energia para uso em diferentes processos. O teor de óleo tem efeito sobre o poder calorífico dos coprodutos de pinhão manso. Quanto maior o teor de óleo residual na torta ou farelo, maior o potencial energético. As cascas, a torta e o farelo apresentaram poder calorífico semelhante à madeira de eucalipto e ao bagaço-de-cana. Este último, muito utilizado em sistemas de cogeração na indústria sucroalcooleira e podem ser utilizados diretamente ou compactados, na geração de calor para processos tanto na indústria processadora como no campo. A torta (obtida por prensagem mecânica) foi o coproduto que apresentou melhores condições para queima direta quando comparada aos demais materiais avaliados

Drying of Eucalyptus Logs from plantations with different spacing between trees

The adoption of dense plantations can reduce the drying time of the logs, by optimizing this step. This study evaluated the drying of eucalyptus wood from plantations with different spacing (3 × 4; 3 × 3; 2 × 3; 1 × 3 m). Five trees were selected per treatment. Logs were removed from the base and at 50% and 100% of commercial height for drying evaluation for 60 days. The diameters of the eucalyptus trees from plantations with wider spacing were bigger, and the productivity per hectare was not affected by the spacing between trees. The planting spacing did not affect the initial moisture, which was higher for those removed from the top of the trees. The logs from the base from the denser spacing showed a drying rate 2.5 times higher than the same logs from the treatment with greater spacing, reducing the final moisture from 37.2 to 18.8%. The logs removed from the top of the trees reached the equilibrium moisture after the drying period. The reduction in the planting spacing reduced the wood moisture and the difference in this parameter between the logs removed from the base and top of the eucalyptus trunks.info:eu-repo/semantics/publishedVersio

Energy properties of wood particles torrefied at different temperatures

The objective of this study was to evaluate the effect of the final torrefaction temperature on the energy properties of wood. It was applied four treatments with three replicates, consisting of untreated wood particles and particles torrefied at temperatures of 170, 220 and 260ºC. Better physical, chemical and thermal properties of the particles were observed as a function of the torrefaction temperature. Comparing with the control group, the particles torrefied at the highest final temperature (260ºC) showed significant differences in bulk density - from 239 to 396kg/m3; the equilibrium moisture content changed from 12.3 to 5.7%; fixed carbon content - from 13.0 to 24.8%; heating value - from 4,465 to 4,945kcal/kg; and energy density - from 882 to 1,727Mcal/m3. It was concluded that torrefaction had a positive effect on the energy properties of the wood.Objetivou-se neste estudo avaliar o efeito da temperatura final da torrefação nas propriedades energéticas da madeira. Foram aplicados quatro tratamentos com três repetições constituídos por partículas de madeira não torrificadas e partículas torrificadas nas temperaturas de 170, 220 e 260 ºC. Observaram-se melhores propriedades físicas, químicas e térmicas das partículas em função da temperatura de torrefação. Comparando com a testemunha, as partículas torrificadas na temperatura final mais elevada (260 ºC) apresentaram diferenças significativas na densidade a granel - de 239 para 396 kg/m3; umidade de equilíbrio higroscópico - de 12,3 para 5,7%; teor de carbono fixo - de 13,0 para 24,8%; poder calorifico - de 4465 para 4945 kcal/kg; e densidade energética - de 882 para 1727 Mcal/m3. Concluiu-se que a torrefação apresentou um efeito positivo nas propriedades energéticas da madeira

Thermal inertia effects of the structural elements in heat losses during the charcoal production in brick kilns

Brazil is the largest producer of charcoal from planted forests with 5.5 million tons in 2016. The Brazilian steel industry consumes 85% of the national production of charcoal from eucalyptus. The walls and floor of industrial brick kilns are built using isolation materials that minimize heat losses during the wood carbonization stage. However, the thermal inertia of these components represents additional heat that must be removed during the charcoal cooling stage, as reflected in the extended process time. This study aims to evaluate the effect of the thermal inertia of the kiln structural elements for the charcoal production. A CFD (Computational Fluid Dynamics) analysis was performed to simulate the heating and cooling of the system composed of wood, carbonization gases, brick walls and floor. A typical industrial kiln with capacity of 700 m3 was modeled and validated using a set of experimental measurements of temperatures during a 4-day carbonization stage with final temperature of 400 °C and an 8 day cooling stage. The temperature profile in the walls was linear, corresponding to a pseudo-steady state, where the thermal load increases with the pyrolysis time. The heat transfer at the floor is extensive; therefore, the adiabatic boundary condition cannot be imposed at the wood bed–floor interface. Our findings provide important information for the improvements in the kiln operation and allow establishment of consistent initial conditions of temperature and heat flux for kinetics models for charcoal cooling in kilns

Composição química da madeira de eucalipto com diferentes níveis de desbaste

The objective of this study was to evaluate different thinning regimes in forest plantations of eucalypt (Eucalyptus grandis x Eucalyptus urophylla) clones to produce timber for cellulose and charcoal to verify whether this effect could affect the proportion of the chemical components of wood. The average initial spacing between plants was 3x3 m and the treatments were: T1= control, T2, T3and T4 with thinning 20%, 35% and 50% of the basal area, respectively. The results were analyzed by Tukey test at 5% probability. According to the results found the lignin content from treatment T4 was higher than that of the others; the groups of uronic acids of the T1 was similar to all other treatments, but the levels of T2 and T4 differed between them. The extractives content of T1was similar to the T2 and T3 and lower than that of theT4; the carbohydrates of T1 were similar to that of T3 and higher than the others. It was concluded that thinning increases the quality of the wood to be used as energy purposes, such as charcoal production, but it did not increase productivity for wood pulp and paper production