Qualidade da madeira de eucalipto e Acacia mangium consorciadas para produção de polpa kraft branqueada

• Autor(a) principal: Lombardi, Lucas Recla
• Data de Publicação: 2013
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/3150
• topic: Branqueamento; Composição química; Propriedades da polpa; Xilana; Bleaching; Chemical composition; Pulp quality; Xylanase; CNPQ::CIENCIAS AGRARIAS::RECURSOS FLORESTAIS E ENGENHARIA FLORESTAL::TECNOLOGIA E UTILIZACAO DE PRODUTOS FLORESTAIS

The objective of this study was to evaluate the quality of the wood of Acacia mangium grown in Brazil in mixed stands with the hybrid Eucalyptus urophylla X Eucalyptus grandis for the production of bleached pulp and paper. Therefore, was evaluated the effects of different ratios of mixed plantation, and generated four treatments characterized by the relationship Acacia and eucalyptus trees planted in the field. The quality of the wood was analyzed by analysis of the chemical composition, specific gravity and anatomical parameters. The performance in kraft pulping was analyzed based on gross income and debugged, demand for alkali and pulp quality. The bleachability of the pulp was analyzed, so that was carried conventional ECF bleaching test a commercial xylanase enzyme aiming to reduce the demand for chlorine dioxide. Was assessed the refining and paper formation originating from the bleached pulp, The paper made with enzymatic pre treatment pulp was compared separately. The parameters of specific density, anatomical and chemical composition of wood were influenced by planting and intercropping. The results showed that the density of Acacia was significantly lower than eucalyptus, in addition, a smaller proportion of Acacia mixed planted with eucalyptus achieved higher densities. The anatomical parameters of fiber as width and lumen diameter were superior to Acacia wood compared to eucalyptus, were also observed larger lumen diameters and width of fibers for treatments subjected to a lower percentage of eucalyptus in the mixed plantation. As the anatomical parameters, chemical composition showed different treatments for lower percentage of eucalyptus, where higher percentages of hemicelluloses and lower lignin content were achieved by these treatments. Another relevant factor is the higher content of extractives and lower proportion of syringyl/guiacyl units of Acacia wood, and such influential factors in the performance of pulping and bleaching. The kraft pulping of wood chips Acacia required higher percentage of alkali than eucalyptus, however the yields were not compromised. The screened yield from the treatments undergoing higher proportion of Acacia planted obtained lower alkali demand without viiicompromising the kappa number and yield. The pulp bleaching Acacia required increased chemical agents that Eucalyptus pulp, yet the proportion of 50% eucalyptus and 50% Acacia obtained good performance in bleaching chemical consumption close to those obtained from eucalyptus. The enzymatic treatment was effective in reducing the demand for chlorine dioxide, in which all treatments obtained reductions in demand from the oxidizing agent. However there was a higher energy demand in refining and mechanical property of bulk was negatively affected. Furthermore, the enzyme stage effluent showed higher organic loading and staining. The mixed plantation of Acacia and eucalyptus was not able to affect significantly the mechanical and physical properties of the paper, and there were no differences between treatments.