Influence of the wood physical properties on the charcoal physical and mechanical properties

Abstract

ResumoA qualidade do carvão vegetal depende significativamente das propriedades da madeira utilizada na sua produção. Atualmente, no Brasil, o maior produtor de carvão vegetal do mundo, este aspecto tem sido mais considerado visando, principalmente, o aumento da produtividade. Assim, a presente pesquisa objetivou analisar a correlação existente entre algumas características físicas da madeira com determinadas propriedades físico-mecânicas do carvão vegetal. Para tanto, foram avaliados oito clones de Eucalyptus e dois clones de Corymbia. Foram coletados discos dos troncos das árvores para a determinação da massa específica, umidade e contrações lineares e volumétricas. Posteriormente, as amostras foram carbonizadas em condições laboratoriais específicas, e o carvão produzido foi submetido a análise de densidade aparente, resistência à compressão paralela às fibras e degradação linear e volumétrica devido aos efeitos da temperatura. Em seguida, para uma melhor interpretação dos resultados, analisou-se conjuntamente as propriedades da madeira e do carvão vegetal por meio da técnica estatística multivariada de correlação canônica. Concluiu-se que a massa específica e a umidade da madeira são os fatores de maior correlação significativa com as propriedades estudadas do carvão vegetal.Palavras-chave: física da madeira, propriedades mecânicas do carvão vegetal, eucalipto, correlação canônica. AbstractThe quality of charcoal is strongly dependent upon the characteristics of the wood from which it originated. In Brazil, the world's largest charcoal producer, this aspect has received special attention to increase the industrial productivity. The present study aimed to analyze the correlation that exists between some physical characteristics of wood and some physical and mechanical properties of the charcoal. Eight clones of Eucalyptus and two clones of Corymbia were studied. Discs from the trunk of the trees were collected to determine the specific gravity, humidity and linear and volumetric shrinkage of wood. After that, the samples were carbonized under specified laboratory conditions and the generated charcoal was analyzed regarding its apparent density, resistance in compression parallel to the grain and linear and volumetric degradation due to the action of temperature. To evaluate jointly the charcoal and wood proprieties, the multivariate technique of canonical correlation was used. It was concluded that specific mass and wood humidity are the most important correlation factors with the charcoal properties under study.

Selection of superior clones of Corymbia hybrids based on wood and charcoal properties

“…However, clone Ct × Cc-5 had the highest WBD which could be more beneficial for charcoal production (Table 2). WBD is one of the most important selection parameters for quality charcoal production because it is associated with better mechanical resistance (Chrzazvez et al 2014, Moutinho et al 2016. A positive correlation was observed between WBD and charcoal density (Brito and Barrichelo 1980).…”

“…Wood basic density directly correlates with the gravimetric yield during the carbonization process and with the apparent relative density of the charcoal (Moutinho et al 2016, Andrade et al 2018. For carbonization, wood basic density greater than 500 kg.m -3 is desirable (Santos et al 2011).…”

Correlation between compression strength parallel of wood and charcoal of Eucalyptus clones

“…min -1 and the breakpoint was established at 20% loss of the material resistance. It indicated the rupture of the sample and the destruction of its structural arrangement and ended the test (MOUTINHO et al, 2016).…”

“…There is no technical standard for performing the test to determine the compression strength parallel or perpendicular to the grain, which makes it difficult to standardize the test. The lack of a specific standard to evaluate resistance to compression has led several authors (COUTO et al, 2015;LANCELOTTI et al, 2010;MOUTINHO et al, 2016) to propose test methodologies. The study on the correlation levels of the mechanical properties between wood and charcoal is relevant, since it allows for the estimate of the value of charcoal resistance based on the mechanical properties of the wood.…”

Influence of Wood Physical Properties on Charcoal from Eucalyptus spp.

“…A range of wood characteristics must be considered in the production of bioreducers. However, basic density is an essential criterion in tree selection, as it is directly proportional to charcoal density and solid gravimetric yield (Pereira et al, 2012;Moutinho et al, 2016). Among the desirable physical characteristics, the steel industry requires that the apparent density of charcoal be as high as possible (> 0.300 g cm -3 ), and that it have high mechanical resistance and low humidity values.…”