This research aimed to evaluate hygroscopicity of charcoal produced under four different final carbonization temperatures. For evaluation of hygroscopicity charcoal samples were conditioned in environments with controlled temperature and relative humidity, using saturated salt solutions. The final carbonization temperature significantly influenced the products yields and the properties of charcoal. The charcoal produced in the final temperature of 750 °C showed the highest adsorption capacity of water, indicated by the moisture content after conditioning, in the higher relative humidity environment. Correlations were observed between adsorbed moisture and the porosity of charcoal produced. HIGROSCOPICIDADE DO CARVÃO VEGETAL PRODUZIDO EM DIFERENTES TEMPERATURASRESUMO: Este estudo teve por objetivo analisar a higroscopicidade do carvão vegetal produzido em quatro diferentes temperaturas finais de carbonização. Para avaliação da higroscopicidade as amostras de carvão vegetal foram acondicionadas em ambientes com temperatura e umidade relativa controladas, utilizando-se soluções salinas saturadas. Os rendimentos dos produtos da carbonização e as características do carvão vegetal foram significativamente influenciados pelas temperaturas finais de carbonização. O carvão vegetal produzido sob a temperatura final de 750 ºC apresentou a maior capacidade de adsorção de água, indicada pela umidade após o acondicionamento. Verificaram-se correlações entre a umidade adsorvida e a porosidade do carvão vegetal produzido.

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ResumoNeste trabalho foram caracterizados resíduos de madeira de origem urbana, antes e depois de submetidos a torrefação. Foram avaliadas cinco composições (tratamentos) de resíduos, compreendendo madeira maciça e painéis reconstituídos, provenientes de uma estação de reciclagem. A torrefação foi realizada em forno elétrico, com atmosfera inerte, saturada em gás nitrogênio, na temperatura de 280 ºC durante 60 minutos. Foram analisadas as propriedades físicas, químicas e energéticas no material in natura e torrificado. Os resultados demostraram que a torrefação aumentou os teores de lignina insolúvel, teor de carbono fixo e poder calorífico superior. Além disso, reduziu os teores de extrativos totais, holocelulose, materiais voláteis, densidade a granel e densidade energética. A torrefação não influenciou nos teores de cinzas, no entanto, mostrou-se eficiente para melhoria da moabilidade dos resíduos. Além disso, o rendimento da torrefação foi afetado tanto pelas características do processo quanto pela composição dos tratamentos avaliados.Palavras-chave: pirolise leve; degradação térmica; biomassa lenhosa; energia da madeira. AbstractThis work analyzed torrefied wooden waste from urban origin. Five compositions of residues (treatments) were analyzed, made up by solid wood and panels from a recycling station. Torrefaction was performed in an electric furnace, within an inert atmosphere saturated with nitrogen gas, and a temperature of 280 °C for 60 minutes. The physical, chemical and energetic properties of raw and torrefied materials were measured. The analysis showed that the torrefaction process led to an increase of acid-insoluble lignin content, fixed carbon content and higher heating value. Furthermore we observed a reduction of extractives, volatile matter, bulk density and energy density. Torrefaction did not affect the ash content, but proved effective to improving the grinding ability of the residues. In addition, the characteristics of the process and samples composition influenced the gravimetric yield of torrefaction.

RESUMOO 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.Palavras-chave: fornos de alvenaria, valor presente líquido, simulação de Monte Carlo. Economic Risk Analysis of Two Systems of Charcoal Production ABSTRACTThis study aimed to analyze the economic viability of charcoal production in kilns-furnace system and "rabo-quente" kilns, as well as the investment risk simulation. The economic analysis was performed by determining the following indicators: Net Present Value (NPV), Equivalent Annual Value (EAV) and Benefit -Cost Reason (B/C). The risk analysis was performed by the Monte Carlo method. Economic indicators were viable. Kilns-furnace system evidenced to be more viable economically. Risk analysis indicated that there is probability to economical unviability of evaluated systems, 0.9% and 27.3% for kilns-furnace system and "rabo-quente" kilns, respectively. Inclusion of risk analysis in economic analysis of charcoal production projects results in greater security to infer on economic indicators.

This study aimed to evaluate the Eucalyptus grandis and Eucalyptus saligna, from production areas of Rio de Janeiro State, intended for energy use. The selection consisted of six trees per specie, at six years old. The wood samples had its basic density determined, then, was subjected to the pyrolysis process with 500 °C of final temperature. Charcoal, pyroligneous liquid and non-condensable gases yields were determined. In addition, the charcoal had its immediate analysis performed to determine the levels of volatiles matter, fixed carbon and ash content. Data were analyzed using descriptive statistics, Pearson correlation and principal component analysis. The correlation analysis and principal component analysis were effective to predict recommended species. Based on the results, the most recommended specie for energy purposes was the Eucalyptus grandis.

This work analyzed the economic viability of four charcoal productive systems from Minas Gerais state, namely: fornos-fornalha, rabo-quente, encosta and superfície. The evaluated systems have an estimated productive capacity of about 100 cubic meters of charcoal per month. Implementation and maintenance expenses and productive parameters were obtained in the literature and from local producers of Lamim (MG), a productive center in the state, during the year of 2018. Silvicultural costs were not considered, only the wood purchase. For the economic evaluation, Net Present Value (NPV), Modified Internal Rate of Return (MIRR), Payback, capex and opex were analyzed, and it was also evaluated the systems’ economic sensitivity to charcoal price and gravimetric yield variations. The main results showed that all the systems were economically viable by NPV criteria; only rabo-quente system was not viable by MIRR criteria; fornos-fornalha system presented the best economic results, greater capacity of net revenues and free cash flow generation, and lower operational expenses. This productive system was also less sensitive to charcoal price fluctuations and to its charcoal yield reduction. Given this fact, its insertion may be attractive in the productive reality of small and medium producers. In addition, the possibility of selling charcoal fines resulted in improvements in economic indicators, especially for traditional production systems: rabo-quente and encosta.

This study aimed to analyze the resistance of the thermally treated wood of Pinus caribaea and Eucalyptus saligna to the biological attack of wood rotting fungi. The heat treatment processes were carried out in electric oven under nitrogen atmosphere, starting from 100 °C until reaching each one of the final temperatures of the process: 120, 140, 160, and 180 °C. The resistance assays were performed for white rot, brown rot, and soft rot fungi. The increase in decay resistance was observed for heat-treated wood of Pinus caribaea at higher temperatures. On the other hand, Eucalyptus saligna showed increased resistance to rotting fungi at all tested temperatures, except for white and soft rot at 120 °C. In general, the heat treatment process showed good results for its use as a wood preservative method.

-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.Keywords: Carbonization; Thermogravimetric analysis; NBR 8112. COMPARAÇÃO DE PROCEDIMENTOS PARA ANÁLISE QUÍMICAIMEDIATA DE CARVÃO VEGETAL RESUMO -As mudanças climáticas, a busca pela sustentabilidade, e as fortes pressões ambientais por alternativas aos tradicionais combustíveis fósseis aumentaram o interesse na pesquisa e utilização de fontes renováveis de energia. Dentre elas se destaca a biomassa do carvão vegetal, advindo de florestas renováveis, amplamente utilizado como termorredutor na indústria siderúrgica em detrimento ao uso do coque de carvão mineral. O objetivo deste estudo foi comparar diferentes procedimentos operacionais de análise química imediata de carvão vegetal. Foram comparados sete ensaios para análise química imediata praticados por empresas e laboratórios brasileiros; o ensaio descrito pela NBR 8112; e um ensaio realizado em analisador termogravimétrico (TGA) com os parâmetros presentes na NBR 8112. Houve diferenças significativas nos teores de materiais voláteis e por consequência nos teores de carbono fixo encontrados. As diferenças entre os ensaios e a NBR 8112 tiveram como causas: tempo de queima em excesso, massa da amostra acima ou abaixo do padronizado, ou recipiente inadequado usado para queima. Observou-se que a determinação do teor de materiais voláteis em TGA deve ser realizada com 372Revista Árvore, Viçosa-MG, v.40, n.2, p.371-376, 2016 LANA, A.Q. et al.tempo de queima igual a 2 minutos para atingir resultados equivalentes aos do procedimento da NBR 8112. Os valores obtidos para os teores de cinzas foram estatisticamente iguais e a granulometria não influenciou as diferenças entre as médias.