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.

Brazil is a large producer of sawmill wastes, commonly used to supply boilers and produce energy. In order to reduce unwanted characteristics of the material, thermochemical conversions through carbonization is an alternative. The aim of this study is to characterize the energetic proprieties of raw biomass and pyrolyzed biomass of sawmill residues. In order to analyze the environmental impact in the emission of pyrolysis gases, the behavior of gases during the thermic treatment was determined. Eucalyptus sp. and Pinus sp. residues slow pyrolysis was performed in an electric kiln, whose gases were conducted through a condensable gas recovery system and an online gas analyzer. The charcoal, bio-oil and non-condensable gases yields were estimated. The wood’s and charcoal’s proximate analysis (extractives, lignin, holocellulosis, ash content), higher heating value, equilibrium moisture and density were appraised. The wood’s chemical components were esteemed. Hardwood and softwood’s charcoal presented several differences, especially in yields due to types of lignin. Hardwoods produce a higher amount of acetic acid in slow pyrolysis. This acid was converted, mainly, in carbon dioxide and e a minor extent in methane and carbon monoxide. The gas release was affected by the temperature and wood’s composition. The main gases resulting from the slow pyrolysis of wood are CO2, CO, CH4, H2. The emission of this gases to the atmosphere in addition to increasing the environmental impact caused by the industry is still a waste of energy that could be harnessed more efficiently. Pyrolysis increased the energetic characteristics of sawmill waste. However, in spite of the advantages of carbonization, ways to mitigate the emission of gases emitted in an operational scale should be evaluated.

Bamboo is a grass known worldwide for its versatility, fast growth and short rotation. The combination of these characteristics makes the species a potential source of biomass for energy use, especially when submitted to a thermochemical conversion treatment, such as pyrolysis. However, the environment aspects of the pyrolysis should be observed, like the emission of greenhouse gases. In this context, the aim of this study was to characterize the proprieties the charcoal and the emission of greenhouse gases of Dendrocalamus asper (Schult f.) Backer ex Heyne, in different pyrolysis temperature (400, 550, 700 °C). The charcoal properties are influenced by the pyrolysis temperature. The increase in the final pyrolysis temperature resulted in a reduction of around 24,5% in the values of charcoal yield and caused an increase in the emission of greenhouse gases (CO 2 , CO, CH 4 , and H 2). Despite the advantages of performing pyrolysis as a thermal treatment, ways to mitigate such emissions are one aspect that has to be evaluated.

The genus Corymbia appears as an option to produce best quality charcoal. The selection of genotypes through multivariate analysis can be a solution when multiple variables influence the result. The aim of this study was to characterize eight genotypes of Corymbia citriodora x Corymbia torelliana for energy and charcoal production, group and indicate the genetic materials with highest potential. The woods specific gravity, high heating value and energy density was determined. Energy density was grouped by the Scott-Knott test; group 1 was appointed for energy generation. The wood was carbonized. Charcoal yield, density, fixed carbon, friability, higher heating value, ash content, fixed carbon yield and energy density were determined. Principal component analysis was performed. Principal component 3 was chosen, as the representation of the ideal genetic material. The scores were calculated, and genetic materials III, VI and VIII are selected for charcoal production. The selection has shown to be efficient.

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 300-450ºC, 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.

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.

The aim of this study was to select superior materials of Eucalyptus spp. using univariate and multivariate statistical analyzes. Twenty-five genetic materials from Eucalyptus spp. collected in Itamarandiba, Minas Gerais were used. The properties of wood and charcoal were determined for all genetic materials, in addition to the gravimetric yield. Data were submitted to Scott-Knott hierarchical clustering algorithm as univariate analysis. For the multivariate approach, a combination between principal component analysis and hierarchical cluster analysis was used. Both analyzes were efficient in the selection of genetic materials for charcoal production. According to the Scott-Knott test, genetic materials 9 and 21 were the most suitable to produce charcoal. By means of the multivariate analyzes the most indicated were 9, 10 and 21. The Scott-Knott test allowed the visualization of the results of each quality parameter independently. On the other hand, the multivariate tools enabled the observation of the relation between the properties of wood and charcoal.

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