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ABSTRACT The wood carbonization with high moisture content reduces the yield, prolongs the carbonization time and results in charcoal with low mechanical strength. Considering this, the reuse of carbonization gases as a source of thermal energy becomes a potential alternative for reducing moisture content quickly and feasibly. The objective of this study was to evaluate the artificial drying of logs using gases from the carbonization system of a furnace and a drying chamber. The drying evaluation was conducted in duplicate using a 35 m³ galvanized metal square dryer and a furnace with a useful volume capacity of 16.8 m³. The average gas intake temperature for drying was 150°C. The eucalyptus logs were divided into three diameter classes (8-14 cm; 14-22 cm; 8-22 cm). The electricity consumption of the dryer was approximately 49.4 kW per ton of wood (dry mass). The highest thermal efficiency was achieved in the drying of 814 cm diameter class logs. The utilization of carbonization gases proved to be effective in reducing wood moisture in all diameter classes, showing potential for large scale utilization.

ABSTRACT Charcoal fines are co-products of the wood carbonization process, unwanted because they reduce the gravimetric yield of the main product, charcoal. It can be produced due to the carbonization process, during the storage and transport of charcoal. Pelletizing charcoal fines increases the energy density of this material, producing a homogeneous fuel with lower moisture content, enabling burning in equipment with high energy efficiency, in addition to desirable properties in energy products such as high fixed carbon content and low moisture content. This study evaluated the effect of moisture content and drying time on the production of black pellets from charcoal fines bound with rice starch (Oryza sativa) on the physicochemical and mechanical characteristics. Black pellets were produced using two proportions of water (10 or 20%) and a drying time of 4 or 6 hours. Black pellets were evaluated for their proximate analysis, elemental composition, moisture content, size, apparent density, calorific value and energy density. The addition of water did not affect the content of volatile matter, ash, and fixed carbon, while the treatment with addition of 20% water and four hours of drying showed a higher moisture content (3.34%). The addition of water allowed for better heat conduction and particle arrangement, producing pellets with a durability greater than 98%. The better arrangement promoted by the addition of 20% water also increased the density of the pellets, resulting in greater energy density. Black pellets can be considered an alternative for residential heating, with T3 treatment (20% - 4h) with a high energy density and better performance in terms of desirable properties for use and commercialization according to the standard EN 14961-6.

Abstract Torrefaction emerges as an industrial process that increases the energy content of conventional biomass. Primary and secondary sludge are the main solid residues generated in the Effluent Treatment Plants of bleached kraft pulp mills, and can be considered as biomass. Typically, these wastes are sent to industrial landfills. The present study aimed to evaluate the technical feasibility of transforming the primary sludge (PS), secondary sludge (SS) and mixed sludges (MIX) into torrefied biomass for energy generation. Three temperatures (260, 290 and 320 °C) and three residence times (20, 40 and 60′) were used in the sludge torrefaction process. Increasing the torrefaction temperature and residence time of the sludges produced several benefits on their physical and chemical properties. They promoted an increase in the heating value, due to the elimination of less energetic compounds and the concentration of the fixed carbon content; caused a reduction of moisture, with a consequent increase in the lower heating value of the sludges; and led to a high energy yield and an increased energy density, important parameters in sludges energy generation. The treatment at 320 °C for 60′ obtained increases of 76%, 27% and 41% over the reference, for PS, SS and MIX, respectively.

Resumo Determinou-se as propriedades físico-químicas de briquetes produzidos a partir de finos de carvão vegetal de Eucalyptus sp aglutinados com adesivo de silicato de sódio. Utilizou-se três granulometrias de finos (20, 35 e 60 mesh) e cinco proporções do adesivo (15, 20, 25, 30 e 35%). Determinou-se a densidade aparente, análise química imediata e poder calorífico, segundo as normas ABNT/NBR 9165, 8112, 8633, respectivamente. Conclui-se que briquetes com granulometria de 20 mesh e 15% de adesivo apresentaram os maiores valores de poder calorífico e aqueles com granulometria de 60 mesh e 15% de adesivo, apresentaram os maiores percentuais de carbono fixo.

Resumo Este trabalho teve como objetivo avaliar o efeito do sulfito de sódio sobre o rendimento gravimétrico em taninos, extraídos da casca de Anadenanthera peregrina. A extração ocorreu em autoclave de laboratório a 100°C durante 3 horas, usando uma relação licor/casca de 20:1; contendo 0%, 1,5%, 3%, 4,5% e 6% de sulfito de sódio sobre a massa seca de casca. A adição de até 3% de sulfito de sódio na extração, aumentou significativamente o rendimento em taninos. Para valores acima de 3%, o rendimento em sólidos totais continuou aumentando porém o índice de Stiasny diminuiu.

Charcoal plays a relevant role in developing countries, with potential to contribute to the energy needs as a cheaper and carbon-friendly alternative. In Brazil, eucalyptus-charcoal has gained attention as an input for metal-steel industries, mostly supplied by small and medium forest producers. Those commonly use rudimentary charcoal-kilns, characterized by higher greenhouse gas (GHG) emissions, reduced productivity and economically unsustainable impacted by their reduced financial management. In order to fulfill this gap, a simplified financial planning model and an economic analysis of a less polluting charcoal productive system, called kilns-furnace system, were performed, also comparing to traditional charcoal-kilns. A differentiated cost of capital pricing model was also proposed, adjusted to bioenergy projects in emerging markets. Results showed that kilns-furnace system presented the best financial indicators, with greater free cash flow capacity, shorter reimbursement period, reduced charcoal production cost, better return on invested capital and a financial resilience even under pessimistic conditions. With its risk-return ratio verified, kilns-furnace larger insertion may be an attraction for charcoal producers, with probable increased long-term economic sustainability when compared to traditional kilns. The proposed cost of capital pricing model opened a new perspective for its calculation in developing countries, and should be used by producers, companies, and government in investment decision and as a guidance for financing lines.

Abstract 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 Wood from planted forests is the main input in the charcoal production chain. However, the heterogeneity of charcoal, in terms of its physical, chemical and mechanical properties, and the low yield in production processes is among the main problems faced by industries. To select the best clones for the production of charcoal for steelmaking, the objective of this work was to evaluate the properties of wood, in addition to the yield and quality of charcoal from different genotypes of Eucalyptus and Corymbia. Five clones of Eucalyptus spp., 8 years old and one of Corymbia torelliana x Corymbia citriodora, 4 years old were studied. In the wood were determined the basic density, structural chemical composition, thermogravimetric analysis (TG/DTG), crystallinity index and higher heating value. Carbonizations were carried out in a muffle oven, with a total time of 270 minutes, starting at 150°C and ending at 450°C. The gravimetric yield, apparent density, higher heating value and proximate analysis of charcoal were determined. The wood basic density varied between 477 and 652 kg/m3, with the highest value observed for the Eucalyptus cloeziana clone. This clone also had the highest total lignin content (32.6%), the highest charcoal yield (36.3%) and charcoal with the highest apparent density (466 kg/m3). The two clones of Eucalyptus urophylla had the highest heating value for charcoal, whose mean was 7545 kcal/kg. The clone of Corymbia torelliana x Corymbia citriodora, having an apparent density greater than 500 kg/m3 at 4 years of age, stood out in terms of productivity. All evaluated clones have potential for charcoal production, however, the Eucalyptus cloeziana clone stood out positively, being the most suitable for charcoal production.

The aim of becoming a society based on the rational utilization of the natural resources, has led to the consideration of many alternatives by academic and industrial sectors. The forest sector may be particularly prominent in trying to achieve these goals when using residues of their processes, for timber and pulp production. One of the most important requirements in society is the energy production. Co-products of wood processing and cellulose mills can be used for bioenergy generation. The densification of biomass involves handling, transportation and storage issues, and furthermore, when industrial forest residues such as lignin are added to this biomass, the final energetic product may have some improved properties, adding value to the chain. The purpose of this study was to evaluate the usage of the woody industrial waste, the sawdust from Joannesia princeps Vellozo enriched with Kraft lignin as an additive, aiming to produce briquettes. One of the main findings from this work was the possibility to obtain a briquette with better properties (higher bulk density and higher resistance) when using 6% of Kraft lignin as an additive and a pressure of 1500 PSI.

Abstract The use of wood panel residues as biomass for energy production is feasible. Heat treatments can improve energy properties while minimizing the emission of toxic gases due to thermoset polymers used in Medium Density Fiberboard (MDF) panels. Torrefaction or pre-carbonization, a heat treatment between 200 and 300 °C with low oxygen availability accumulates carbon and lignin, decreases hygroscopicity, and increases energy efficiency. The objective of this work was to evaluate the energy parameters (immediate, structural, and elementary chemical composition, moisture content, and yield) and density in torrefied MDF panels. The torrefaction improved the energetic features of coated MDF, decreasing the moisture content, volatile matter, and consequently, concentrating the carbon with better results in the samples torrefied for 40 min. The densitometric profiles of the torrefied MDF, obtained by X-ray densitometry, showed a decrease in the apparent density as torrefaction time increased. The digital X-ray images in gray and rainbow scale enabled the most detailed study of the density variation of MDF residues.

Abstract Pellets are widely used for power generation because they use renewable raw material with easy storage, transport and high energy density. However, the structural fragility, disintegrating during handling, transport and storage, is one of the main problems of pellets, but the addition of binders/additives can minimize this fragility. The objective of this study was to evaluate the properties of wood pellets with the addition of starch (corn and wheat) and kraft lignin in different proportions. Pellets were produced with the addition of starch (wheat and corn) and kraft lignin in the proportions of 1, 2, 3, 4 and 5% in relation to the mass of wood particles of Pinus sp., with 12% moisture (dry basis), classified in 3 and 1 mm sieves and compacted in a pelleting press in the laboratory, according to European standard EN 14961-2. Physical and mechanical properties of the pellets were evaluated and their densitometric profiles obtained from the Faxitron LX-60 X-ray equipment. Corn starch and kraft lignin additives at 4% improved pellet properties (density, fines and hardness), reducing their losses during handling, storage and transport.

ABSTRACT Traditional methods of economic evaluation of wood and charcoal production projects are based on indicators analysis, however, they are subject to market variations and uncertainties. The study was carried out in the city of Lamim, Minas Gerais State, to evaluate the economic viability of wood and charcoal production using the kiln-furnace system, due to the need to know the economic viability of this new production system. Sensitivity analysis using the Monte Carlo technique was performed on costs and revenues. The wood and charcoal production cash flow was elaborated and the following criteria were used in the economic analysis: Net Present Value (NPV), Benefit-Cost Ratio (BCR), Equivalent Periodic Value (EPV), and Internal Return Rate (IRR). The wood and charcoal production sensitivity analysis was carried out using the software @RISK, according to the VPE parameter, which allows comparing projects with different durations. Wood production was economically viable, with NPV of $40.26 ha-1 and EPV of $ 16.80 ha-1, with an average production cost of $13.51 m3 wood-1. The EPV mean value found in the sensitivity analysis was $18.33 ha-1. The charcoal production was economically viable, with NPV of $4.43 mdc charcoal-1 and EPV of $3.52 mdc charcoal-1. The EPV mean value found in the sensitivity analysis was $9.80 mdc charcoal-1. It was possible to conclude that the wood and charcoal production are economically viable in the region.

Research indicates the use of adsorbent materials to remove pollutants from wastewater and effluents, which can be obtained from renewable materials such as biomass, biopolymers (chitosan) or composites. Thus, the objective of this work was to produce and evaluate activated carbon (AC) and chitosan composite films as adsorbents of neutral red dye. AC films were produced using CO2 and water vapor. The variables of the activation process were time (1 and 2 h) and temperature (600 and 750 °C). Five films were produced, with one pure chitosan (T1) film and four activated carbon with chitosan films (T2, T3, T4 and T5). The T2 film refers to activated carbon produced at 600 °C for 1 h + chitosan, T3 to activated carbon produced at 600 °C for 2 h + chitosan, T4 to activated carbon produced at 750 °C for 1 h + chitosan and T5 to activated carbon produced at 750 °C for 2 h + chitosan. The T5 film increased its adsorption capacity by approximately 87% and its removal efficiency of neutral red dye by 43% compared to T1. The presence of activated carbon in the films provided an increase in the adsorption capacity of the neutral red dye.

The differentiation between the charcoal produced from (Eucalyptus) plantations and native forests is essential to control, commercialization, and supervision of its production in Brazil. The main contribution of this study is to identify the charcoal origin using macroscopic images and Deep Learning Algorithm. We applied a Convolutional Neural Network (CNN) using VGG-16 architecture, with preprocessing based on contrast enhancement and data augmentation with rotation over the training set images. on the performance of the CNN with fine-tuning using 360 macroscopic charcoal images from the plantation and native forests. The results pointed out that our method provides new perspectives to identify the charcoal origin, achieving results upper 95 % of mean accuracy to classify charcoal from native forests for all compared preprocessing strategies.

Abstract Our study aims to determine the energetic quality of residues from the manufacturing of jatropha and eucalyptus, as well as to evaluate the physical properties of the briquettes made with different proportions of these biomasses. The following proportions were used for this study: 100% eucalyptus; 75% eucalyptus; 50% jatropha and 50% eucalyptus; 75% jatropha; and 100% jatropha. The apparent density of the residues, the immediate chemical product, the highest calorific value (HCV), the apparent density, the energy density, the usable calorific value (UCV), the lowest calorific value (LCV), the breaking strength of the briquettes (FR) and the hydroscopic moisture balance (HMB) were verified. Although the energetic characteristics of the jatropha residues are not superior to those of eucalyptus, this biomass adds favorable mechanical characteristics to the briquettes comprised of greater proportions of jatropha to eucalyptus, guaranteeing the energetic properties of the briquette, as well as reducing the production cost.

Thermal treatments have the effect of reducing the hygroscopicity and improving the resistance to microbiological attack of wood by the degradation of its chemical constituents. During the treatments, the mass of the wood is reduced, a factor that can affect the quality of the materials according to their use. The objective was to verify the effect of the thermal treatment variables on the thermogravimetric properties and the chemical composition of Eucalyptus grandis. The treatments were carried out in a vacuum oven with three atmosphere conditions - vacuum; N2; vacuum+N2 at temperatures of 140, 180 and 220 °C for 6 hours. It was observed that the mass loss during treatments differed only according to the temperatures used. The extractive content, total lignin and holocellulose presented significant changes only at 220°C in all three atmospheres. In the thermogravimetric analysis, the greatest value of residual mass was found in the treatment that used nitrogen and 220 °C, thus demonstrating that this treatment was more invasive, leading to the conclusion that the vacuum application can help to reduce the degradation of the constituents of the eucalypti wood. wood, which can lead to the production of thermally treated wood without great losses in the mechanical properties.

Abstract The charcoal production when performed in woods with high moisture content negatively impacts the pyrolysis and causes an increase of greenhouse emissions. The aim of this study was to investigate the effects of moisture on the production and quality of charcoal for the pig iron industry. The slow pyrolysis of Eucalyptus sp. was carried out in four different wood moistures, 0, 20, 40 and 60% (dry base). The charcoal and gas yield decreased according to the increase of wood moisture. On the other hand, the bio-oil yield and charcoal friability increased along with the moisture content. The proximate analysis, bulk density and higher heating value of the charcoal were not influenced by the moisture content. The use of wood with moisture content below 20% in the production of charcoal is an alternative to improve productivity, contributing for the economic sustanainability of this sector.

The low diversity of forest tree species used in the formation of planted forests in Brazil, based mainly on Eucalyptus and Pinus genus, has led to study of alternative woods that show good productive potential. Thus, Pterogyne nitens species (madeira-nova), which shows good growth in Brazil’s northeast region, it has aroused interest despite little research on their technological characteristics. The objective of this study was to analyze the potential of Pterogyne nitens wood for the charcoal production. Nine-year-old timbers were harvested in Vitória da Conquista town, Bahia state. The woods were fragmented and carbonized in a muffle furnace with electric heating and final temperatures of 300°C, 450°C and, 600°C. Analysis were performed of carbonization process (yield in charcoal, condensable gases and non-condensable gases), apparent density (0% moisture), friability, superior heating power and, immediate chemistry of charcoal. Based on the results, it could be concluded that the fixed carbon and superior heating value of produced charcoal increased with the increasing of the final carbonization temperature. On the other hand, the increasing of the final carbonization temperature caused a reduction in the content of volatile materials and charcoal yield. The yield of non-condensable gases and friability of charcoal increased with the elevation of final carbonization temperatures from 300ºC to 450ºC, remaining constant to higher temperatures. Finally, the final carbonization temperature of 450°C was considered optimal for carbonization of that studied wood.

Pyrolysis is a promising technology for thermal conversion of lignocellulosic biomass into a higher added value fuel. The aim of this study was to analyze the potential of four agroforestry biomass 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 biomass used was 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 content. In the second part was showed the bio-coal proprieties, such as, gravimetric and fixed carbon yield, fixed carbon and ash content. 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 found in the bamboo and eucalypts. The bagasse and straw bean biomasses possess high concentrations of ash and low lignin content when compared with the other biomasses assessed and are less suitable to produce bio-coal.

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 Pelletization is a technique used to compact biomass, generating a granulated material called pellets, with high energy density. The objectives of this work were to produce pellets made from Sorghum (Sorghum bicolor) residuals and to evaluate its quality. Firstly, the residuals were characterized, followed by the production of the pellets. An experimental framework was adopted, entirely randomized with three treatments: T1 – 100% Sorghum, T2 – Sorghum + addition of wheat starch, and T3 – Sorghum with the addition of steam. There was also a comparison of the properties of the pellets with values determined by the European standard. It was concluded that Sorghum biomass (Sorghum bicolor) residuals are viable for pellet production; products obtained were homogenous and easy to handle; the treatment T1 presented the best results for pellet production; all treatments produced pellets within the specifications of the EN 14961-6 (DIN, 2012) standard for non-wood pellets.

ABSTRACT Torrefaction and briquetting are two techniques that improve the quality of the biomass and facilitate direct use as fuel. The objective was to evaluate the effect of torrefaction temperature on the properties of the compound briquettes made from sugar cane bagasse and Eucalyptus sawdust. After sample preparation and particle analyses, briquettes were produced with the mixture of the two biomasses, a total of five compositions (0, 25, 50, 75 and 100%) at 120 °C and pressure of 1500 PSI. Subsequently, the briquettes were torrefied at temperatures of 180, 220 and 260 °C, for a period of 15 minutes. According to the results, both biomasses of Eucalyptus sawdust and sugar cane bagasse showed potential for the production of briquettes. The torrefaction reduced hygroscopicity and increased the calorific value of compound briquettes. The ideal composition for the production of briquettes is 100% Eucalyptus. The composition of 50% Eucalyptus + 50% sugar cane bagasse is also a great option, as some bagasse parameters were excellent. 260 °C was the best temperature to promote energy savings.

ABSTRACT The objective of this work was to evaluate the influence of different useful areas provided by the planting spacings (3 × 1, 3 × 2, 3 × 3, 3 × 4 m) on the production and permeability of heartwood and sapwood of Eucalyptus grandis and Eucalyptus grandis × Eucalyptus urophylla clones at 4 years old. Regardless of the clone, there was no effect of planting spacing on the heartwood/sapwood relation and wood permeability. All clones showed a heartwood decrease with increased height, regardless of planting spacing, and E. grandis (B) was the only one that had its heartwood percentage positively and significantly correlated with the dendrometric variables (DBH and commercial height). The use of the dymethil yellow compound was indispensable in defining the heartwood and sapwood regions in the samples from 50% of the stem height. The heartwood permeability was low in all evaluated clones, suggesting vessel obstruction by tyloses or other deposits, while sapwood permeability reached 405.4 cm3/cm.atm.s.

ABSTRACT The goal of this study was to evaluate the performance and efficiency of a transmission system of carbonization gas to the combustion chamber of a burner. The gas transportation network (GTN) consists of removing the gases from the chimney of the furnaces, which pass through pipes until they reach the burner. A heating system was built surrounding the pipe that leads the carbonization gases to avoid the condensation of gases and the generation of wastewater in the pipes. These gases were named trace gases and guided in the opposite direction to the carbonization gases. This study monitored of the temperature of the GTN by analyzing different points of the process with thermocouples attached on the pipes. The correlation between the various temperatures in the sampling points determined the Pearson’s correlation coefficient to 95% of probability and a regression between the variables that had a significant association. The average temperature of carbonization gases in the chimney outlet was 116ºC, and it entered the burner with an average temperature of 166.7ºC, providing an increase of 50.7ºC on the temperature. The average temperature in the burner chimney outlet for trace gas was 218.35ºC, and it was released to the atmosphere with a temperature of 125.2ºC. The thermal loss was 93.15ºC. The GTN that uses trace gas is presented as an alternative to the flow of gas carbonization. This system is effective regarding non-condensing gases through the pipes, allowing a better use of energy and avoiding the generation of undesirable effluents.

Wood, in general, is a material with excellent properties; however, some features may limit its use. In this sense, various thermal treatments are emerging as alternatives to improve the technological properties of wood. In this context, this study aims at analyzing the effects of time and temperature (hydrothermal treatment and freezing) on the physical and mechanical properties of Eucalyptus grandis W. Hill ex Maiden. Three trees were selected, and only the heartwood was used to obtain the test body dimensions of 30 × 8 × 3 cm (length × width × thickness). The treatments were carried out at three temperatures of -20, 60, and 100°C, each at three exposure times (5, 10, and 15 h). Temperature treatment at -20°C was conducted in a domestic freezer, while the treatments at 60 and 100°C were administered in a Parr reactor, where the timber was submerged in water. Regardless of the exposure time, the timbers heat-treated at 100°C showed more efficiency, since this treatment unclogged the pores, reduced hygroscopicity, and promoted further darkening and uniformity of color, without changing the density and mechanical strength of the wood.

In order to improve global effectiveness of energy production, a strategy is the model of bio-refineries in which all the components of biomass are totally used to produce a range of products with aggregated value. The kraft lignin is one of the products originated in the process of cellulose production that can be used in making densified products. The objective of this work was to evaluate the behavior of the addition of extracted kraft lignin of black kraft liquor in briquette manufactures with furniture industry waste, in the form of shavings and panel particles in different proportions. The briquettes were produced in laboratory briquetting, using the temperatures of 60, 75 and 90 o C. The pressing and cooling time was 5 minutes and pressure 68,9 x 10 5 N.m -2 (1000 PSI). The briquette quality was evaluated through determining the mechanical properties. The kraft lignin in adequate proportions and temperature showed advantages in the increase of resistance and the durability of the briquettes. The kraft lignin presented advantages such as agglutinative in briquette productions from wood waste at a pressing temperature of 90 o C with addition of 20% of kraft lignin, and at pressing temperatures of 60 and 75 o C at a proportion of addition of 40 and 60% of kraft lignin to wood waste, respectively.

ABSTRACT The climate change, the quest for sustainability and the strong environmental pressures for alternatives to traditional fossil fuels have increased the interest in the search and use of renewable energy sources. Among them stands out the biomass of charcoal coming from renewable forests, widely used as a thermal reductant in the steel industry in the detriment of the use of mineral coal coke. This study aimed to compare different operating procedures of immediate chemical analysis of charcoal. Seven essays to immediate chemical analysis were compared, spread between procedures performed by Brazilian companies and laboratories, the test described by NBR 8112 and one realized with a thermogravimetric analyzer (TGA) using the parameters of the NBR 8112. There were significant differences in the volatiles matter content and consequently in the fixed carbon contents found. The differences between the procedures and the NBR 8112 were caused by an excess burning time, a mass sample above or below the standard or inappropriate container used for burning. It observed that the TGA appraisal of the volatiles content must be carried out with a burning time equal to 2 minutes to obtain results similar to those of the NBR 8112 norm. Moreover, the ash content values were statistically identical and the particles size did not influence the differences between means.

ABSTRACT This study had the objective of comparing two methodologies of sampling, Simple Random Sampling (ACS) and Stratified Random Sampling (ACE) to determine the optimum number of roundwood samples to obtain the moisture content of the population. In order to achieve this goal, different percentages of allowable error (5,10,15 and 20%) were considered for each sampling methodology. In the conduction of this study, the samples were randomly taken from a lot of 250 steres of wood, 144 roundwood of three meters of length and distributed in four classes of diameter. Later, the moisture content of these samples was determined. And, from these values, the population estimates (average, standard deviation, variance, coefficient of variation, and standard error) by ACS and ACE methods, helped to determine the optimum number of roundwood (n) to be sampled from different percentages of allowable error adopted in this study at 95% probability. According to the results, the amount of roundwood to be sampled from ACS for each allowable error 5, 10, 15 and 20% was respectively 214, 55, 25 and 14. For the ACE (proportional allocation) the amount of roundwood was 141, 35, 16 and 9 for ACE (optimal allocation) this number was 136, 34, 15 and 8. It was concluded that the most indicated sampling method for this study, considering the allowable error, was the ACE method.

ABSTRACT For several wood uses, such as pulp, paper and charcoal, the presence of the bark is undesirable, compromising production. Thus, this study aimed to evaluate the influence of different plant spacings on the properties of the bark of a clone of Eucalyptus grandis x E. camaldulensis at seven years of age at five different plant spacings. The wood discs were removed from the trees at 0, 25, 50, 75 and 100% of the commercial height; then we performed thickness, basic density, gross calorific value and mineral content analysis of bark. There were no significant differences among treatments for the bark gross calorific value and thickness. For the bark basic density, the highest values were found in trees planted in wider plant spacings and considering the mineral content, there was a significant difference only for P, Mn and Zn.

The objective of this study was to determine the influence of the chemical properties (elemental composition, levels of extractives, lignin total and holocellulose) and the syringyl/guaiacyl, wood of different Eucalyptus genetic materials in the production of charcoal. It was used in the study four hybrid clones, at age of 7 years, 6 trees per clone, totaling 24 sampling units. There was significant difference, at 5% significance, between treatments for elemental composition, levels of extractives, lignin total and holocellulose and the wood syringyl/guaiacyl, as well as for gravimetric yields in charcoal, condensable gases and non-condensable gases, levels of fixed carbon and volatiles, and for the higher calorific value of charcoal. For the ash content and relative apparent density of charcoal were not observed significant differences at the same level of significance. Concluded that there is variability in the wood quality of four evaluated genetic materials, having the same, distinct correlations, thus the yield and the quality of charcoal. All genetic material presented satisfactorily gravimetric yield in charcoal and quality. The woods of clones with low syringyl/guaiacyl ratio showed an increase in yield in charcoal. The chemical composition of woods from the four clones, in general, showed no significant correlations, the 5% significance level, at the yield and quality of charcoal.

This study aimed to evaluate the anatomical changes that occur with charred wood and determine the anatomical properties, basic wood density and apparent density of charcoal Eucalyptus clones, besides elucidating the possible existing significant correlations. The scanning electron microscopy was performed in the transverse, longitudinal and tangential longitudinal and radial wood charcoal sections. In the morphological analysis of the pores and the apparent density was made. In general, the anatomical features such as pore radius and the wood fibers showed little or no change due to carbonization of coal surface and showed well defined structures. The changes in cellular elements of wood were mainly related to the quantitative parameters such as wall thickness and pore diameter fibers. The clones showed satisfactory basic density of wood for charcoal production. The anatomical parameters were significantly correlated with basic wood density and apparent density of charcoal, especially, in this study, the fraction of the fiber wall.

The use of biomass for energy purposes has been highlighted in as a way to reduce dependence on non- renewable energy sources. Macaw palm, Acrocomia aculeata (Jacq.) Lodd. ex Martius , is an arborescent palm and has a high energy potential from the fruit processing. The aim of this study was to characterize the macaw palm residues after the fruit processing to evaluate its use “in natura” and as charcoal. The endocarp showed higher fixed carbon content, heating value and bulk density compared with other residues and lower ashes content. The heating value of endocarp charcoal was the highest, whereas the volatile matter levels of epicarp charcoal showed higher results. All evaluated residues from the macaw palm fruit processing have potential in power generation, especially the endocarp and the epicarp. The endocarp charcoal has suitable characteristics as source of energy and as a reductant.

RESUMO Este trabalho teve como objetivo caracterizar o perfil térmico de fornos tipo "caipira" utilizados pelo setor de cerâmica vermelha em Parelhas, na região do Seridó, RN, visando propor intervenções estruturais que possam colaborar para aumentar a produtividade e qualidade dos produtos, otimizar o consumo de madeira e mitigar as perdas durante o processo de queima. O trabalho foi desenvolvido na Cerâmica Esperança, na cidade de Parelhas, RN. Foram realizados quatro tratamentos com três repetições, sendo a argila o parâmetro utilizado como referência para distinguir os tratamentos. Foram monitorados a quantidade da lenha, a qualidade da telha e o tempo de cada queima. Foram aferidas temperaturas em 15 pontos marcados na superfície da carga enfornada, em intervalos de 30 min a partir do pré-aquecimento até o final da queima, utilizando um pirômetro de mira a laser. Os resultados indicaram que a madeira utilizada como lenha apresentou densidade sem diferença significativa entre os tratamentos, umidade dentro dos padrões permitidos e consumo heterogêneo, enquanto a argila teve pouca retração linear quando submetida ao fogo e o forno, perfil térmico heterogêneo. O parâmetro do fio, que é utilizado como referência para o controle da queima, foi significativo, embora com oscilações diferenciadas, razão por que não deve ser o único critério para finalização do processo de queimas. A parte central do forno foi a área que atingiu maiores temperaturas de maneira homogênea, com maior concentração de produtos de primeira qualidade; a curva de temperatura ideal foi do tratamento 1, com uma média de 18,66% de produto de primeira qualidade, com temperatura de 100 °C a 400 °C.

RESUMOUm importante aspecto a ser considerado na produção de carvão vegetal é o longo período de resfriamento dos fornos de alvenaria, acarretando na baixa produtividade e exigindo maior número de fornos para suprir a demanda de produção. Pesquisas têm sido desenvolvidas para a redução do tempo de resfriamento dos fornos retangulares, utilizando trocadores de calor. Dessa forma, o objetivo deste trabalho foi avaliar três modelos de trocadores de calor que promovam a redução significativa do tempo de resfriamento. A pesquisa foi realizada na unidade produtora de carvão vegetal Buritis, da Empresa Arcelor Mittal Bioflorestas, localizada na cidade de Martinho Campos, MG. Foram avaliados três diferentes trocadores de calor (Modelos 1, 2 e 3), determinando o tempo, em dias, que os fornos retangulares levavam para atingir a temperatura de 50 ºC em relação ao resfriamento natural. O Modelo 1 apresentou ganho real no tempo de resfriamento de 12,5%; o Modelo 2, ganho real de 38%; e o Modelo 3, com fluxo de gás convencional, apresentou ganho médio de 32%, enquanto no fluxo de gás invertido o ganho foi de 43%. Conclui-se que os trocadores de calor avaliados foram eficientes na redução do tempo de resfriamento dos fornos retangulares para produção de carvão vegetal, elevando, assim, a produtividade dos fornos. O trocador de calor Modelo 3, com fluxo de gás invertido, apresentou o maior ganho real no tempo de resfriamento, além do menor número de focos de incêndio durante o descarregamento do carvão vegetal.

O objetivo deste trabalho foi avaliar a influência da idade, da irrigação e do espaçamento na composição química da madeira de eucalipto. O material utilizado constituiu de dois clones de Eucalyptus grandis x Eucalyptus urophylla com idades de seis e 12 meses, provenientes de plantios em duas regiões, uma irrigada e outra não irrigada, com espaçamentos de 3 x 0,5; 1,5 x 2; 3 x 1; 3 x 2; e 3 x 3 m. Na análise química da madeira, foi realizada uma amostragem composta dos seis discos obtidos ao longo do fuste das árvores. Ao final do trabalho, foi possível verificar a influência da idade, do espaçamento e da irrigação na composição química da madeira e que o teor de holocelulose não seguiu padrão de tendência, havendo diferentes resultados em cada tratamento. Maiores valores de teor de extrativos ocorreram nos clones não irrigados e com idade de seis meses, não sendo verificadas influências dos espaçamentos. Os maiores resultados de teor de lignina foram obtidos nos maiores espaçamentos, embora não tenha sido verificado tendência de resultados de teor de lignina para idade e tratamento com irrigação. O teor de cinzas foi superior na idade de seis meses, e não se verificou tendência de resultados nos diferentes espaçamentos e regiões.

ABSTRACT Inclined trees produce reaction wood, whose properties are distinct from normal wood. This situation can affect the production of charcoal. This study was conducted to evaluate the quality of charcoal derived from reaction wood in trees of a commercial plantation inclined due to the action of wind. We used six year old wood from a Eucalyptus grandis xEucalyptus urophylla hybrid from plantations located in Minas Gerais. The physical and chemical properties of the wood were determined as well as the gravimetric yield and charcoal properties. According to the results, there were significant differences between the properties of the reaction and normal wood, with the reaction wood having lower levels of lignin and extractives, greater holocellulose content and low specific gravity. However, these characteristics of reaction wood did not significantly affect the properties of its charcoal.

ABSTRACT This study aimed to estimate the biomass and energy of a clonal planting short rotation experiment with hybrids of Eucalyptus urophylla ST Blake x Eucalyptus grandis (Hill) Maiden, deployed in 3 m x 3 m spacing, at the Academic Unit Specialized in Agricultural Sciences, Macaíba/RN. The analysis were performed at the Laboratory Panels and Wood Energy, Federal University of Viçosa, in which the following ratings on wood three cultivars (GG100 ; AEC0144 and AEC0224) were performed: determination of basic density, high calorific power, chemical analysis, thermogravimetric analysis and subsequent calculations for estimating the mass production and energy were performed. The base (10 cm from the ground), the third and two thirds of commercial tree height: composed for analysis, taken from three points along the stem samples were used. The design of the experiment was a completely randomized. Data were subjected to analysis of variance and the means were compared by Tukey test (a= 0.05). The clone who excelled in the first year of planting was the GG100 with 11,805 kW.h.ha-1 of energy productivity, followed by clone AEC0224 (6,755 kW.h.ha-1) and AEC0144 (4,405 kW.h.ha-1). The performance of this clone was due to mainly the higher volumetric growth. The wood quality among clones showed little difference. It should stimulate the deployments of species of short rotation in the state of RN to supply the elevated energy demand of forest biomass in the region.

RESUMO O objetivo deste trabalho foi avaliar a resistência ao cisalhamento na linha de cola de juntas de Eucalyptus sp. coladas com diferentes adesivos e diferentes gramaturas. Para a colagem das juntas foi utilizada a madeira de Eucalyptus sp., dois adesivos de cura a quente (fenol-formaldeído e melamina-formaldeído), quatro adesivos de cura a frio [resorcinol-formaldeído, silicato de sódio, PVA (acetato de polivinila) e poliuretano à base de mamona], empregando-se gramaturas de 150 g, 200 g e 250 g/m2 em face dupla. Foram determinados aresistência ao cisalhamento e à falha na madeira, e cisalhamento em condição úmida. Os resultados obtidos indicaram que os adesivos de mamona e resorcinol apresentaram maior resistência ao cisalhamento na linha de cola na condição seca. Os adesivos de mamona e fenol-formaldeído apresentaram maior percentual de falha na madeira na condição seca.

ABSTRACT The use of forest biomass or its derived charcoal as firewood can generate environmental and economic advantages for the Brazilian energy matrix. In this context, the main objective was to evaluate the energy potential of certain eucalyptus genetic materials, which are used by the charcoal production sector. We have evaluated six materials of Eucalyptus ssp. at the age of seven years from commercial plantations, spaced 3 x 3m, grown in the Alto Vale do Jequitinhonha, in Minas Gerais. Based on the production data, the average annual increment and the physical and chemical analyzes of the wood and the charcoal produced with it, we have estimated parameters to compare the potential of each genetic material, such as mass and energy of wood and charcoal per hectare, as well as the energy density. The results show that a material of Eucalyptus urophylla has greater energetic potential in relation to the others because it presents higher energy/ hectare estimated for its wood and consequently for charcoal produced with it. However, a material of Eucalyptus cloeziana presented a higher energetic density of the wood and its charcoal, showing advantages mainly in the transport.

RESUMO O objetivo deste trabalho foi analisar a viabilidade econômica da produção de carvão vegetal em sistema fornos-fornalha e fornos do tipo rabo-quente e realizar a simulação de risco de investimento. A análise econômica foi realizada pela determinação de Valor Presente Líquido (VPL), Valor Anual Equivalente (VAE) e Razão Benefício-Custo (B/C). A análise de risco foi realizada pelo método de Monte Carlo. O sistema fornos-fornalha apresentou maior viabilidade econômica. Os indicadores econômicos se mostraram viáveis e a análise de risco indicou probabilidade de os projetos serem inviáveis economicamente de 0,9% e 27,3% para o sistema fornos-fornalha e fornos rabo-quente, respectivamente. Conclui-se que a inclusão da análise de risco nas análises econômicas resulta em maior segurança para inferir sobre os indicadores econômicos.

O objetivo deste trabalho foi avaliar o efeito do tratamento térmico em algumas propriedades de painéis de partículas, produzidos com resíduos de embalagens de Pinus sp. Foi utilizado o adesivo à base de ureia-formaldeído, na quantidade de 8%. O experimento foi desenvolvido em um fatorial 4 x 3 x 3, sendo quatro proporções de partículas (25, 50, 75 e 100%), termorretificadas, três temperaturas de tratamento térmico (180, 200 e 220 ºC) e três repetições, totalizando 36 painéis. Foram produzidos mais três painéis com partículas sem tratamento térmico (testemunhas), totalizando 39 painéis. A absorção de água, inchamento em espessura e resistência à tração perpendicular foram determinadas de acordo com a Norma ABNT/NBR 14810-3 (2002). Os resultados desses testes foram comparados com os valores estabelecidos nas Normas ABNT/NBR 14810-3 (2002) e DIN 68 761 (1) (1961). A estabilidade dimensional dos painéis aumentou com a adição de partículas termorretificadas, enquanto as propriedades mecânicas foram reduzidas. O efeito da adição de partículas termorretificadas nas propriedades dos painéis é maior à medida que se utilizam maiores temperaturas de tratamento térmico.

Este trabalho teve como objetivo determinar a influência da idade e de diferentes materiais genéticos de Eucalyptus sp. na produção de madeira para energia. Neste estudo, foram avaliados três clones de Eucalyptus sp., em quatro idades diferentes, aos 3, 4, 5 e 7 anos, sendo provenientes da Gerdau S/A. De cada árvore foram retirados cinco discos (0%, 25%, 50%, 75% e 100% da altura comercial do tronco), bem como determinados a densidade básica, o poder calorífico superior e a análise elementar da madeira, e, como base nesses valores, foi possível estimar a quantidade de energia m-3. Observou-se que houve efeito da idade e do material genético para a densidade básica da madeira e para o poder calorífico superior. Verificou-se ainda que a quantidade de energia m-3 aumentou com a idade, e houve diferença significativa entre os três materiais genéticos avaliados. O clone GG 680 apresentou melhor desempenho dessa variável, apresentando, aos 7 anos, 2.943 kW.h.m-³. Cabe ressaltar que a escolha do melhor material genético deve levar em consideração as características tecnológicas da madeira, bem como a sua produtividade e efetividade técnica de produção.

Este trabalho teve como objetivo avaliar o perfil de decomposição térmica da madeira de oito espécies utilizando as técnicas de termogravimetria (TGA) e calorimetria diferencial exploratória (DSC), bem como a consistência desses métodos para decidir quais espécies devem ser indicadas para produção de energia e carvão vegetal, comparando-os com os rendimentos gravimétricos da carbonização obtidos a partir de carbonizações em mufla de laboratório. Para as análises por TGA e DSC, amostras de serragem foram aquecidas à taxa de 10 °C min-1, sob atmosfera de nitrogênio, em vazão de 50 ml min-1 até a temperatura final de 600 °C. Foram determinados os valores de densidade básica e poder calorífico superior da madeira. As carbonizações foram realizadas em mufla de laboratório à taxa de 50 °C h-1 até a temperatura máxima de 450 °C, obtendo-se os rendimentos em carvão vegetal. Também foram determinados os valores de densidade aparente do carvão das oito espécies após a carbonização. Os resultados das análises térmicas indicaram perfis de decomposição pirolítica das madeiras e evidenciaram aquelas mais estáveis à ação térmica. O comportamento da estabilidade térmica das madeiras das oito espécies foi confirmado pela análise dos rendimentos da carbonização em mufla, em comparação com a análise por TGA e DSC. As madeiras de Aspidosperma pyrifolium e Mimosa tenuiflora apresentaram maior estabilidade térmica e, portanto, maiores rendimentos em carvão vegetal, bem como maiores densidades aparentes. As técnicas de termogravimetria e calorimetria diferencial exploratória são satisfatórias para avaliação da decomposição térmica das madeiras e garantem consistência na escolha de madeiras que resultam em maior rendimento e maior qualidade do carvão vegetal.

http://dx.doi.org/10.5902/198050989293The objective was to evaluate the energy potential of woods of species under forest management plan from Seridó region in the Rio Grande do Norte state. It was used the wood species Jurema Preta, Pereiro, Marmeleiro, Catingueira, Mororó, Imburana, Jurema Branca and Mofumbo, at 20 years old, originated from the Dominga´s farm in the Caicó/RN municipality. The density, the content of volatiles, the ash and fixed carbon, calorific value, elemental composition and carbon/nitrogen (C/N) and carbon/hydrogen (C/H) analysis were carried out in the wood. Additionally, the amount of energy produced in kW.h.m-3 and kW.h.ha-1 for all species was estimated. The experiment was conducted in a completely randomized design with eight treatments (species), four replicates (sample trees), adding up to 32 sampling units. There were significant differences, at 5% significance between treatments for all variables, except for hydrogen percentage and C/H ratio. It was concluded that Mororó´s wood shows high energy potential, and along with Jurema Preta, presents higher energy generation per m3, and provides greater economy for the same productivity. The energy potential Jurema Preta wood´s stands out among the species. Pereiro´s wood stands for energy production per hectare. Marmeleiro and Jurema Branca´s woods are indicated as direct burning potential and Imburana´s wood is not recommended for power generation.

O objetivo deste trabalho foi avaliar a qualidade da madeira de clones de Eucalyptus spp. destinados à produção de carvão vegetal, estudar correlações entre propriedades da madeira e do carvão e identificar os clones com maior potencial para uso energético. Os dados de clones de 18 povoamentos, no Cerrado mineiro, foram submetidos às análises multivariada de correlação canônica; de componentes principais; e de agrupamento. As propriedades do carvão vegetal são fortemente correlacionadas às da madeira, principalmente a densidade aparente do carvão vegetal e o rendimento gravimétrico. Os materiais mais velhos e de maior densidade básica da madeira apresentam maior qualidade para uso energético. A análise de componentes principais é eficiente para ranquear os materiais quanto à qualidade da madeira, e o método de agrupamento é capaz de estratificar com sucesso os clones pela qualidade da madeira.

O objetivo deste trabalho foi avaliar a degradação térmica da madeira de diferentes clones de Eucalyptus, por meio de análises termogravimétrica (TG/DTG) e de calorimetria exploratória diferencial (DSC), estabelecendo-se suas relações com a produção de carvão vegetal. Foram utilizados seis clones de Eucalyptus spp. aos 7,5 anos de idade, provenientes de um teste clonal pertencente a uma empresa florestal. Foram realizadas as análises TG/DTG e DSC, sob atmosfera de gás nitrogênio. As curvas TG/DTG mostraram três faixas de degradação térmica, atribuídas à secagem da madeira e à degradação de hemiceluloses e celulose. Não foi detectada faixa específica de degradação de lignina. As curvas DSC evidenciaram um pico endotérmico entre as temperaturas de 50 e 100 ºC, o que pode ser atribuído à perda de água da madeira. A liberação de calor iniciou-se em temperaturas acima de 275 ºC, para todos os clones avaliados, sendo observados dois picos exotérmicos. As análises térmicas da madeira (TG/DTG e DSC) não apresentaram variações expressivas entre os clones. Conclui-se que, através das técnicas estudadas, é possível identificar as principais fases das reações de liberação ou absorção de energia e perda de massa, que estão diretamente ligadas à qualidade do carvão vegetal.

Embora nos últimos anos diversas pesquisas tenham sido desenvolvidas com o intuito de melhorar os índices de qualidade da madeira (densidade básica, composição química), grande parte da produção brasileira de carvão ainda ocorre em fornos com baixo rendimento gravimétrico e com emissões de gases poluentes. Na tentativa de alterar esse cenário, este trabalho objetivou avaliar o funcionamento de um sistema forno-fornalha e também o ajuste de faixas de controle da carbonização em função do tempo e da temperatura, levando-se em consideração a degradação térmica da madeira, com vistas a maximizar o rendimento em carvão vegetal. Foram construídos três fornos circulares de alvenaria acoplados a uma fornalha, para queima dos gases gerados durante a carbonização. O controle da carbonização foi realizado através da mensuração da temperatura interna com sensor infravermelho. De acordo com os resultados, o controle da carbonização realizado com base nas faixas de carbonização proporcionou rendimento médio de 33% de carvão, 8% de atiço e 3% de finos. A fornalha mostrou-se eficiente na redução de emissão de fumaça para o ambiente, funcionando durante um terço do tempo de carbonização. Conclui-se que o sistema forno-fornalha apresenta produção satisfatória de carvão vegetal, com baixa emissão de fumaça durante a carbonização da madeira.

The objective was to evaluate the energy potential of woods of species under forest management plan from Seridó region in the Rio Grande do Norte state. It was used the wood species Jurema Preta, Pereiro, Marmeleiro, Catingueira, Mororó, Imburana, Jurema Branca and Mofumbo, at 20 years old, originated from the Dominga´s farm in the Caicó/RN municipality. The density, the content of volatiles, the ash and fixed carbon, calorific value, elemental composition and carbon/nitrogen (C/N) and carbon/hydrogen (C/H) analysis were carried out in the wood. Additionally, the amount of energy produced in kW.h.m-3 and kW.h.ha-1 for all species was estimated. The experiment was conducted in a completely randomized design with eight treatments (species), four replicates (sample trees), adding up to 32 sampling units. There were significant differences, at 5 % significance between treatments for all variables, except for hydrogen percentage and C/H ratio. It was concluded that Mororó´s wood shows high energy potential, and along with Jurema Preta, presents higher energy generation per m^3, and provides greater economy for the same productivity. The energy potential Jurema Preta wood´s stands out among the species. Pereiro´s wood stands for energy production per hectare. Marmeleiro and Jurema Branca´s woods are indicated as direct burning potential and Imburana´s wood is not recommended for power generation.

A torrefação, também conhecida como pré-carbonização, é um tratamento térmico, em baixas temperaturas (200 a 300 ºC), aplicado a um material lignocelulósico com o objetivo de melhorar suas propriedades energéticas. Desenvolveu-se este estudo visando avaliar o efeito da temperatura de torrefação nas propriedades de cavacos de eucalipto. Utilizando uma mufla, os cavacos de eucalipto foram submetidos a quatro tratamentos térmicos com temperaturas de 150, 200, 250 e 300 ºC. Os cavacos de madeira permaneceram nestes patamares de temperatura por dez minutos. Foram realizadas análises físicas e químicas dos cavacos torrificados e in natura. Os resultados foram submetidos à análise de variância (ANOVA) e quando estabelecidas diferenças significativas entre eles, aplicou-se o teste Tukey, a 95% de significância. Com o aumento da temperatura de torrefação observou-se maior concentração de lignina e de carbono fixo, menor umidade de equilíbrio higroscópico, maior poder calorífico superior, menor teor de materiais voláteis e menor rendimento gravimétrico. Recomenda-se a torrefação em temperatura de 250ºC, visto que os cavacos torrificados nesta condição apresentaram melhor desempenho, com densidade energética de 4004 MJ/m³.

O objetivo deste estudo foi quantificar os estoques em volume, biomassa e carbono na madeira de um fragmento de Caatinga Arbustiva-Arbórea, na região Nordeste do Brasil, no Município de Caicó, RN. Realizou-se o inventário e a amostragem do material biológico para análises de biomassa e carbono. Para a conversão de volume de madeira em biomassa foi obtida a densidade básica da madeira de oito espécies que representavam 91% do valor de importância (VI) do fragmento. A porcentagem de carbono dessas espécies foi determinada por análise elementar da madeira. O estoque de carbono foi determinado considerando-se a porcentagem de carbono multiplicada pela biomassa de cada árvore. Para as espécies que não foram analisadas (9% do VI) utilizou-se um valor de densidade básica média () e da média de carbono (), ponderados pelo valor de importância das espécies amostradas. Foi observado um estoque volumétrico de madeira igual a 15,5 m³ ha-1. A biomassa determinada foi de 12 t ha-1, que correspondeu a um estoque de carbono de 5,7 t ha-1.