No abstract

No abstract

Eucalypts are among the most important short-rotation hardwoods, planted worldwide for the pulp and paper industry. Even though the genus comprises over 700 species, only about a dozen species are used for pulping purposes, therefore, showing the potential for diversification. Six-year-old eucalypt trees from 12 species (Eucalyptus botryoides, Eucalyptus camaldulensis, Eucalyptus globulus, Eucalyptus grandis, Corymbia maculata, Eucalyptus ovata, Eucalyptus propinqua, Eucalyptus resinifera, Eucalyptus rudis, Eucalyptus saligna, Eucalyptus sideroxylon, and Eucalyptus viminalis) were analyzed for chemical composition, fiber morphological, pulping and handsheet paper properties to determine their kraft pulping suitability. The 12 species showed substantial differences regarding extractives (6.1-18.9%), lignin (21.6-30.8%) and holocellulose content (55.4-70.1%). The high inter-species variation in chemical composition produced pulps with different yields (between 38.9 and 49.8%) and degree of delignification (kappa number between 11.6 and 24.2). The combination of these results with the morphological and handsheet properties suggests that E. globulus, E. ovata, E. grandis, E. saligna and E. botryoides have the best overall characteristics for kraft pulping.

The present work determines the chemical and thermal characteristics as well as the phytochemical and antioxidant potential of the polar extractives of the Picea abies bark from an industrial mill, their wood and bark components and also different bark fractions obtained by mechanical fractionation (fine B1, Φ<0.180 mm, medium B3, 0.450 < Φ<0.850 mm and coarse B6, 2 < Φ<10 mm). The aim is to increase the knowledge on the Picea abies bark to better determine possible uses other than burning for energy production and to test an initial size reduction process to achieve fractions with different characteristics. Compared to wood, bark presented similar lignin (27%), higher mineral (3.9% vs 0.4%) and extractives (20.3% vs 3.8%) and lower polysaccharides (48% vs 71%) contents. Regarding bark fractions the fines showed higher ash (6.3%), extractives (25%) and lignin (29%) than the coarse fraction (3.9%, 19% and 25% respectively). Polysaccharide contents increased with particle size of the bark fractions (38% vs 52% for B1 and B6) but showed the same relative composition. The phytochemical profile of ethanol and water extracts presented higher contents for bark than wood of total phenols (2x higher), flavonoids (3x higher) and tannins (4-10x higher) with an increasing tendency with particle size. Bark antioxidant activity was higher than that of wood for ferric-reducing antioxidant power (FRAP, 10 vs 6 mmolFe2+/gExt for the ethanol extract) and free radical scavenging activity (DPPH, 6 vs 18 mg/L IC50 for the ethanol extract) methods. The different bark fractions antioxidant activity was very similar. Bark thermal properties showed a much lower volatiles to fixed carbon ratio (V/FC) than wood (3.1 vs 5.2) although the same higher heating value (20.3 MJ/kg). The fractions were quite similar. Bark presented chemical features that point to their possible upgrade, whether by taking advantage of the high extractives with bioactive compounds or the production potential for hemicellulose-derived oligomers with possible use in nutraceutical and pharmaceutical industries.

1RESUMO -O objetivo deste trabalho foi analisar os resíduos gerados nas marcenarias do município de Viçosa, Minas Gerais, e propor ações potencializadoras para o seu melhor aproveitamento. Foram coletados dados sobre os resíduos de madeira gerados em 17 marcenarias da cidade, por intermédio da aplicação de questionários. Os resultados mostraram que a serragem, os sarrafos, as maravalhas e os cavacos foram os principais tipos de resíduos produzidos, sendo a serragem o resíduo mais abundante. As máquinas que mais geraram resíduos foram a desengrossadeira e a desempenadeira. A maioria das marcenarias doava ou vendia os resíduos produzidos. Constatou-se que não havia preocupação por parte dos proprietários das marcenarias quanto à agregação de valor ao resíduo gerado e quais os danos ambientais que estes poderiam ocasionar. A partir dos resultados, propuseram-se as seguintes medidas de melhor aproveitamento dos resíduos gerados: geração de energia através da queima direta de resíduos oriundos da madeira sólida, fabricação de briquetes, fertilizantes e de "pequenos objetos de madeira" (POM).Palavras-chave: Viçosa-Minas Gerais, Marcenarias e Resíduos de Madeira. AN ANALYSIS OF THE WOOD RESIDUES GENERATED BY CARPENTRY SHOPS IN VIÇOSA, STATE OF MINAS GERAIS ABSTRACT -The objectives of this work were to analyze the residues produced by carpentry shops in

The changes in the cellulose structure of eight Eucalyptus species (E. botryoides, E. globulus, E. grandis, E. maculata, E. propinqua, E. rudis, E. saligna and E. viminalis) in a mild torrefaction (from 160 °C to 230 °C, 3 h) were studied in situ and after cellulose isolation from the wood by solid-state carbon nuclear magnetic resonance (13C NMR), wide angle X-ray scattering (WAXS), Fourier transform infrared spectroscopy (FTIR) and by analytic pyrolysis coupled with gas chromatography and mass spectrometry (Py-GC/MS). Changes in molecular weight were assessed by viscosimetry. A small decrease in cellulose crystallinity (ca. 2%–3%) was attributed to its amorphization on crystallite surfaces as a result of acid hydrolysis and free radical reactions resulting in the homolytic splitting of glycosidic bonds. The degree of the cellulose polymerization (DPv) decreased more than twice during the heat treatment of wood. It has been proposed that changes in the supramolecular structure of cellulose and in molecular weight during a heat treatment can be affected by the amount of lignin present in the wood. The limitations of FTIR and Py-GC/MS techniques to distinguish the minor changes in cellulose crystallinity were discussed.

Heat treatment improves some wood properties namely: equilibrium moisture, dimensional stability and durability and mechanical properties. In this study, the heat treatment was applied to woods of three natural species from Brazil: Aspidosperma populifolium (peroba mica), Dipteryx odorata (cumaru) and Mimosa scabrella (bracatinga). The woods were heated in an oven under vacuum and under nitrogen, at 180, 200, and 220°C for one hour. The untreated and heat-treated woods were characterized in relation to equilibrium moisture content, basic density, shrinkage, Janka hardness, and bending MOR and MOE according to NBR 7190 standards. All the thermal rectified woods showed a reduction in the hygroscopic equilibrium content, especially when the heating was under vacuum from 13-15% in the untreated woods to 1-3% for vacuum treatment at 220 °C. The dimensional stability was improved to only a small extent e.g. volumetric shrinkage tended to decrease with increasing temperature. The mechanical properties were affected differently for the three wood species. Heat-treated cumarushowed increased Janka hardness, MOR and MOE; and peroba mica increased MOR and MOE but not Janka hardness; while bracatinga was less influenced by the heat treatment.

Agroforestry industries, such as sugar-alcohol, food, and logging, produce large quantities of waste, used to generate energy from direct burning. The application of other processes, such as torrefaction and briquetting, can increase the profits from the use of agro-industrial waste for energy generation. Briquetting is an alternative for using these wastes, allowing the compaction of the biomass, generating a biofuel with high energy density, and which is more homogeneous and easier to store and transport. The objective of this study was to evaluate the physical and chemical properties of four biomass types (wastes from sawed eucalypt and pine wood, coffee pruning wastes, and sugarcane bagasse) torrefied at 300 °C and compacted (briquetting) at pressures of 6.21, 8.27, and 10.34 MPa. The torrefaction increased the fixed carbon content, ash, and calorific value, and reduced the volatile material content and hygroscopic equilibrium moisture of the biomasses. The volatile material content was lower and the fixed carbon higher in the coffee pruning waste, the ash content higher in the sugarcane bagasse, and the calorific value higher in the pine and eucalypt wood. The briquetting and the torrefaction processes increased the biomass bulk density, and the useful calorific value, respectively, and consequently the energy density of the briquettes produced with torrefied raw material under high pressure. The mechanical properties of the briquettes produced with all materials increased with the compaction pressure. Torrefaction and briquetting increased the energy potential of the biomasses evaluated to produce energy from clean technology.