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The substantial expansion of the Brazilian pulp and paper industry in the last years resulted in a significant increase in the solid waste generation. This paper investigates the production of pellets using primary sludge from the effluent treatment plant of a kraft pulp mill, as a fuel for producing energy, using a novel wet route process. The pellet samples were produced in a laboratory pelletizing press, which has a horizontal circular matrix. The samples were characterized by moisture content, high heating value, ash content, dimensions (diameter and length), mechanical durability and fines content. The net heating value and energetic density were also measured. The pellets manufactured with primary sludge were compared to the European standard for non-woody pellets. Pelletization caused a reduction of the moisture content by 37.8 %, and increased the net heating value by 41 % and bulk density by approximately 39 %, which resulted in a 263 % increase in the material´s energetic density. Pellet production using a wet route process was appropriate for the primary sludge, and produced pellets with a high mechanical durability (99.3 %) and low fines content (0.062 %), indicating the potential of thermal valorization for incineration in the biomass boiler to produce high-quality steam. [ABSTRACT FROM AUTHOR]

The aim of this study was to compare the properties of wood and charcoal of Eucalyptus sp., from two silvicultural systems (replanting and coppicing), in addition to assessing the economic viability of both systems, through the financial indicators Net Present Value (NPV), Internal Rate of Return (IRR) and Payback. The study was carried out in a charcoal producing company, located in the municipality of Itamarandiba, Minas Gerais, Brazil. The results showed that the wood from the coppice system has a lower Mean Annual Increment and a higher heartwood/sapwood ratio, producing a more friable charcoal and with lower productivity compared to the replanting system. Regarding the economic analysis, both systems were economically viable, with an IRR greater than the discount rate and a positive NPV. Comparatively, the economic results of the coppice system were slightly better, presenting less vulnerability in the sensitivity analysis regarding fluctuations in the price of charcoal. The option for coppice may be interesting for the producer due to its lower financial expenditure and satisfactory economic results, although with lower product quality [ABSTRACT FROM AUTHOR]

Pyrolysis is a promising technology for thermal conversion of lignocellulosic biomasses into a higher added value fuel. The aim of this study was to analyze the potential of four agroforestry biomasses to produce energy as a raw material or as a bio-coal. In this study, slow pyrolysis was conducted in three final temperatures to evaluate the bio-coal production of four agroforestry biomasses widely available in Brazil. The biomasses used were sugarcane bagasse (Saccharum sp.), bamboo (Dendrocalamus giganteus), straw bean (Phaseolus vulgaris) and eucalypts wood chips (Eucalyptus sp.). In the first part was presented the raw biomasses proprieties, such as lignin, carbon, hydrogen and ash contents. In the second part was showed the bio-coal proprieties, such as gravimetric and fixed carbon yields, fixed carbon and ash contents. These bio-coal results were showed as a function of final temperature of pyrolysis. The best energy indicators for bio-coal production, such as fixed carbon yield, high heating value, was observed in the bamboo and eucalypts. The bagasse and straw bean biomasses have high concentrations of ash and low lignin content when compared with the other biomasses assessed and are less suitable to produce bio-coal. [ABSTRACT FROM AUTHOR]

The aim of the study was to evaluate the use of thermogravimetric analysis in the pre-selection of genetic materials. Twenty-five Eucalyptus spp. genetic materials were used. The analysis of the data consisted of three stages; first, was carried out an exploratory study of the wood and charcoal properties. Subsequently, a Pearson correlation analysis was performed between the parameters of thermogravimetric analysis (TGA) and the properties of wood and charcoal. Finally, once the presence of significant correlations between these properties was verified, pre-selection of genetic material was carried out. The loss of mass in the temperature range of 300-450°C, from thermogravimetric analysis (TGA), showed the highest number of correlations between wood and charcoal properties, which allowed the use of this TGA variable in pre-selection of genetic materials. Genetic materials 9 (Hybrids of E. urophylla and E. maidenii), 10 (Hybrids of E. urophylla and Eucalyptus sp.), 19 (Hybrids of E. urophylla, E. camaldulensis, E. grandis and Eucalyptus sp.) And 21 (Hybrids of E. urophylla, E. camaldulensis, E. grandis and Eucalyptus sp.) presented potentials for charcoal production, through pre-selection. [ABSTRACT FROM AUTHOR]

Briquetting is a form to aggregate value in the biomass production chain, to re-use sustainably waste and to provide high-quality solid biofuels, as well as to enable the development of the energy market. The aim of this study was to evaluate the potential of the production of briquettes from epicarp waste of macauba fruit and verify the influence of different temperatures and compaction pressures on the chemical, physical, and mechanical characteristics of the briquettes. The epicarp was reduced to particles and, then classified, dried, and characterized for their physical and chemical properties. The briquettes were produced by using compression pressures of 62, 83, and 103 bar and temperatures of 90 and 120 °C. The effect of these factors upon the variables studied was verified through regression analysis. The increase of pressure and temperature contributed to greater mass loss of the briquettes. Apparent density and energy density increased due to temperature rise. High values of energy density were obtained, which demonstrates the potential of the macauba fruit epicarp to produce briquettes for generation of thermal energy. [ABSTRACT FROM AUTHOR]

The combination of pelletization and torrefaction allows for obtaining pellets with higher energetic density. Thus, biomass becomes more attractive and usable for energetic purposes, and therefore, knowing the chemical properties becomes important to guarantee the quality of the torrefied pellets for fuel. The objective of this study was to evaluate the effect of torrefaction of Pinus sp. pellets on their chemical properties. The wood was previously transformed into particles and dried to 16% moisture content for further pelleting. For the torrefaction, the pellets were dried to 0% moisture content and subjected to heat treatment in a screw type reactor at the temperatures of 210, 250, and 290 °C and the times of 10, 20, and 30 minutes. In order to determine the chemical properties, the structural chemical composition, immediate chemical composition, elemental composition, and thermogravimetric analysis were performed. The torrefaction promoted significant changes in the chemical properties of Pinus sp. pellets, especially regarding the proportional increase of carbon content in detriment to oxygen reduction, increase of the thermal stability, and proportional increase of the lignin content by the reduction of the hemicelluloses. This improves the energetic quality of the biomass and turns it into a more competitive fuel when compared to fossil fuels. [ABSTRACT FROM AUTHOR]

Wood is exposed to different atmospheric conditions in the production of charcoal due to the occurrence of rainfall and variation in relative humidity. However, there is a lack of scientific information related to charcoal hygroscopicity and desorption capacity depending on water content. Thus, in the present study, we analyzed the influence of carbonization temperature in brick kilns on the hygroscopic capacity of charcoal from a 7-year-old Eucalyptus sp. wood. Charcoal was produced at final temperatures of 340, 380, 420, and 460 °C. Raman spectroscopy, Fourier-transform infrared absorption spectroscopy, scanning electron microscopy, and surface area measurement were performed to identify structural changes in charcoal. The charcoal samples were exposed to six different saline solutions to simulate the relative humidity of the environment, ranging from 33 to 98%, for the determination of the moisture adsorption capacity. The charcoal surface area values ranged from 7.9 (340 °C) to 12.3 m2 g−1 (460 °C). Charcoal porosity increased by 14.4% with increasing temperature. The adsorption capacity decreased with the rising final carbonization temperature. An average reduction of 9.9% between the moisture adsorbed by the charcoal samples produced at 340 °C and 460 °C was observed. The increase in surface area and porosity of charcoal as a function of temperature resulted in the loss of environmental moisture adsorption capacity due to the removal of carboxyl and hydroxyl groups in the temperature range analyzed. Physical mechanisms were more relevant in the water–charcoal relationship, which can directly influence the drying process of the bioreducer in stockyards. [ABSTRACT FROM AUTHOR]

Cerrado is the second largest Brazilian morphoclimatic domain. Despite being a region of great ecological importance, it has been the target of constant threats caused by anthropogenic activities, mainly those related to agriculture and livestock farming. With a rich biodiversity still not fully known and constantly being devastated, the Cerrado lacks studies. The objective of this study was to microscopically analyze the wood of Cerrado tree species. Wood samples were collected from nine tree species in a Cerrado area located in Monte Carmelo, Minas Gerais. Microscopic analyses were carried out on permanent histological slides and macerated material, following IAWA Committee standards. This work provided information on species whose wood had not been previously described in the literature, such as Machaerium opacum and Eugenia dysenterica, as well as on previously described species. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Among the technological alternatives to improve the quality and use of eucalyptus wood is heat treatment, as the wood has some features that may limit its use, such as dimensional instability, high anisotropy, and heterogeneous coloring. This study is aimed at evaluating the effect of time of hydrothermal treatment on physical, chemical, and mechanical properties of solid wood of Eucalyptus grandis. We used three trees of E. grandis, selecting only the heartwood, and prepared test specimens with dimensions of 30cmx8cmx3cm (length, width, and thickness). The hydrothermal treatment was performed in a Parr reactor using three reaction times (5, 15, and 25min) at 140°C. Partial removal of extractives occurred, especially in the outer layer of wood. There was an increase of up to 58% of its permeability because of the partial clearing of the vessel elements. There was no degradation of the main constituents of the wood, so loss of mechanical strength was observed. The hydrothermal treatment promoted the partial removal of the hydroxyl groups and/or a structural rearrangement of the hemicelluloses and cellulose, causing a reduction of the hygroscopicity of E. grandis. [ABSTRACT FROM AUTHOR]

Coarse Woody Debris (CWDs) are constantly exposed to the natural decomposition process of wood, which can lead to a change in its physical–chemical properties. However, these changes have not yet been fully elucidated, requiring further studies to help to understand the effect of this process on CWDs degradation. Thus, the objectives of this study were: (i) verify if the decomposition affects the physical–chemical properties of the CWDs; (ii) verify if the structural chemical composition of the CWDs is altered as a function of decomposition, using immediate chemical and thermogravimetric analysis. Wood samples were collected from the CWDs to carry out these analyses, considering pieces with diameters ≥ 5 cm separated into 4 decay classes. The results indicated that the average apparent density decreased as a function of the increase of CWDs decomposition (0.62–0.37 g cm−3). The averages contents of Carbon and Nitrogen suffered less impact with the increase of CWDs decompositions, ranging from 49.66 to 48.80% and 0.52 to 0.58%, respectively. Immediate chemical and thermogravimetric analysis indicated a loss of holocelluloses and extractives and an increase in the concentration of lignin and ash throughout the decomposition process. The weight loss analyzed by thermogravimetric analysis was greater for less decomposed CWDs and with larger diameters. The use of these analyzes removes the subjectivity of CWDs decay classes, reducing the number of tests to determine CWDs physical–chemical properties and increasing the studies accuracy focused on the carbon cycle of these materials. [ABSTRACT FROM AUTHOR]

To increase production and decrease the heterogeneity of charcoal produced in rectangular kilns, the control of carbonization must be carried out based on the kiln internal temperature. The objective of this work was to analyze the maximum carbonization temperature and the time of thermal degradation at temperatures above 290 °C based on the internal kiln wall temperatures, in addition to evaluating charcoal properties in different positions of a rectangular kiln. Wood from the hybrid Eucalyptus urophylla x E. grandis at seven years of age was used for carbonization in rectangular kiln where temperature was monitored and controlled. Process parameters and charcoal quality were evaluated in seven positions in the rectangular kiln. Positions 1 and 7 had higher maximum temperature values and thermal degradation time at temperatures above 290 °C in comparison with the other positions, which presented similar values. There was no significant effect of kiln position on the characteristics of charcoal, which presented average values of 234.61 kg m-3 of bulk density; 55.87% of pieces with size greater than 30 mm; 19.77% of fines (granulometry < 9.5 mm); and 20.80% of friability, 75.39% of fixed carbon, 24.37% of volatile materials, and 0.24% of ash. It was concluded that the kiln position affects the temperature and time of thermal degradation; however, the control of temperature guarantees the production of homogeneous charcoal throughout the kiln, presenting satisfactory quality for steel industry usage. [ABSTRACT FROM AUTHOR]

The shorter natural durability and low energy density of eucalyptus wood hampers its use in generating energy. Torrefaction or pre-carbonization, which is treatment in low oxygen with temperatures between 200 °C and 300 °C, accumulates carbon and lignin, decreases the hygroscopicity, increases the energy efficiency, and reduces the attractiveness of wood to xylophagous organisms, such as termites. The objective of this study was to evaluate the resistance of fresh and torrefied Eucalyptus urophylla (20 min at temperatures of 180 °C, 220 °C, and 260 °C) to dry wood termites (Cryptotermes brevis), following IPT standards. The torrefaction process increased the resistance to dry wood termite attack after 45 d of exposure, with mass losses five times greater in the in natura wood compared with the wood torrefied at 260 °C. The larger visual damage to the in natura chips confirmed its lower resistance to dry wood termites. Torrefaction at 260 °C increased the resistance to dry wood termites and was more efficient with a lower mass loss and wear, and caused a greater mortality of dry wood termites. [ABSTRACT FROM AUTHOR]

[Display omitted] • Near-infrared spectroscopy and chemometrics were used to study the fungal degradation of four different biomass types; • A first developed model classifies raw and torrefied biomasses after fungal exposure; • Others models predict energy properties of raw and torrefied biomasses after fungal exposure; • Near-infrared spectroscopy with chemometrics assesses biomass degradation. Lignocellulosic biomasses have some characteristics that hinder their use as fuel. Further, the biodegradation processes that can occur during storage can affect their energy properties. Torrefaction can improve their energy properties while reducing the impacts of storage. Near-infrared (NIR) spectroscopy could be a promising tool to estimate changes to biomass properties during storage. A series of waste feedstocks, including: sugarcane bagasse, coffee husk, eucalyptus, and pine were torrefied at 290 °C in a screw reactor, over 5, 7.5, 10, 15, or 20 min. Then, raw and torrefied biomasses were submitted to leaching and to white and brown-rot fungi, to simulate storage conditions. The weight loss (WL) due to fungal degradation after 2, 4, 8, and 12 weeks was measured and the high heating value (HHV) of all biodegradation steps, including raw and torrefied samples after leaching, were determined. All the samples were analysed by NIR spectroscopy and chemometric models were then developed. Firstly, partial least squares for discriminant analysis (PLS-DA) models successfully classified the four different residual biomasses into raw and torrefied forms according to fungal decomposition. Secondly, partial least squares regression (PLSR) models showed potential utility in an industrial context as a standardized continuous method to predict the HHV during biomass storage steps. While, PLSR models did not present good accuracy when estimating WL resulting from fungal degradation, they can be useful for screening during decision making. Further studies are required to improve and develop more efficient models to predict the fungal degradation level of stored biomasses. For exemple, in considering the class of torrefied biomasses, the model could show better predictive capacity due to less variability in the data. These results highlight the potential of NIR spectroscopy as a simple, fast, and efficient tool to analyze the degradation process over time. Such a rapid and non-destructive characterization tool could be very useful in industry to assess biomass property changes during storage. [ABSTRACT FROM AUTHOR]

Wood-based panels made of waste and recycled raw material are lacking of dimensional stability. The aim of this study is to evaluate the potential beneficial effect of heat treatment (HT) on the properties of particleboards produced from waste of Pinus sp. used for packaging. The wood particles were heat treated at 180°C, 200°C and 220°C after grinding, and panels were produced with incorporation of 25%, 50%, 75% and 100% HT particles. The materials served as reference were particles without HT. Mass loss at 180°C and 200°C was small but increased significantly to 10.6% at 220°C. The HT caused a partial degradation of hemicelluloses, thereby the relative lignin content increased from 29.7% to 37.8% for the HT220°C samples. Thermogravimetry revealed higher thermal stability of the HT particles. The equilibrium moisture content decreased with HT, e.g. panels with HT220°C showed 30% lower compared to the reference. Swelling of the panels was lowered by 30% (panel with 75% HT material) compared to the reference. The results with HT pine were successful in terms of dimensional stability and lower hygroscopicity; however, the panels lost some strength properties. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]