Biological resistance of heat-treated wood of Pinus caribaea and Eucalyptus saligna

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

Development and evaluation of a metal furnace for combustion of wood carbonization gases

Este estudo teve por objetivo desenvolver e avaliar o desempenho de uma fornalha metálica para combustão dos gases da carbonização da madeira, para a redução das emissões de gases poluentes e geradores do efeito estufa na produção de carvão vegetal. Foram realizadas cinco carbonizações, com faixas de temperatura de carbonização predefinidas, utilizando-se madeira de Eucalyptus sp., na Unidade Experimental de Carvão Vegetal da Universidade Federal de Viçosa - MG. O rendimento gravimétrico, as propriedades do carvão vegetal, os perfis térmicos do forno e da fornalha e os seus parâmetros de funcionamento foram determinados. Para caracterização dos gases não condensáveis, CH4, CO, CO2, H2 e O2, foram realizadas coletas com intervalo de 1 hora durante o processo. Por meio de um analisador de gases foram determinadas as concentrações antes e após a fornalha para averiguar a redução das emissões de gases tóxicos nocivos ao homem e ao meio ambiente. O rendimento gravimétrico e a qualidade do carvão vegetal foram satisfatórios tanto para uso siderúrgico como para o uso doméstico. Concluiu- se que a fornalha funcionou adequadamente, ocorrendo em tempo médio de combustão dos gases de 42% do tempo total de carbonização, e com reduzido consumo de combustível auxiliar. A combustão dos gases na fornalha levou à redução média de 86% de monóxido de carbono e 88% de metano durante o período em que houve combustão, o que contribui para salubridade local e redução da emissão de gases tóxicos e geradores do efeito estufa.This study aimed to develop and evaluate the performance of a metal furnace for combustion of gases produced by wood the wood carbonization, for the reduction of pollutant and greenhouse gases emissions. Five carbonizations were performed, with temperature ranges predefined, using Eucalyptus sp. Wood, in the Charcoal Experimental Unit of the Federal University of Viçosa - MG. The gravimetric yield, the charcoal properties, the thermal profile of the kiln and the furnace, and the furnace operating parameters were measured. To characterize the non-condensable gases, CH4, CO, CO2, H2 and O2 were made collections with interval of one hour during the process. The gases concentrations before and after the furnace during carbonization were determined using a gas analyzer, checking the reduction of the harmful to humans and the environment toxic gas emissions. The gravimetric yield and quality of charcoal were satisfactory for ironmaster and domestic use. It was concluded that the furnace functioned properly, occurring an average gases burning time of 42% of the total carbonization time, and reduced consumption of auxiliary fuel. The gases combustion in the furnace resulted in a mean reduction of 86% carbon monoxide and 88% methane during the period in which the combustion occurred, contributing to the health of local and reduction in emission of toxic and greenhouse generators gases.Conselho Nacional de Desenvolvimento Científico e Tecnológic

Masonry kiln to increase productivity through the external cooling of charcoal

O Brasil é o maior produtor e consumidor de carvão vegetal do mundo, entretanto, a maioria da produção é realizada em fornos de alvenaria rudimentares, de pequenas dimensões que, geralmente, não ultrapassam os 12m3 de volume interno. Estes fornos são pouco engenheirados e utilizam pouca ou nenhuma tecnologia, o que reflete numa produtividade aquém do potencial de um carvão vegetal muito heterogêneo. Nesta transformação da madeira em carvão nos fornos de alvenaria está presente uma marcante dicotomia aonde, em uma primeira etapa, é necessário o aquecimento e a retenção do calor e, posteriormente, a dissipação da energia contida no sistema para retirada da carga produzida, o que acaba por elevar o tempo de produção e, consequentemente, reduzir a produtividade. É importante ressaltar que nesta fase inicial, da conversão propriamente dita, existe pouca ou nenhuma margem para redução de tempo, uma vez que é mais dependente das características da matéria-prima, visando assegurar a qualidade do produto final. Neste contexto, o objetivo desta pesquisa foi desenvolver um novo forno experimental de alvenaria para produção de carvão vegetal que proporcionasse ciclos mais curtos, elevando a produtividade e, simultaneamente, assegurando a qualidade do carvão. Assim, o foco da pesquisa foi dado a etapa de resfriamento, tendo sido traçadas estratégias para acelerar o arrefecimento do carvão vegetal que, neste caso, foi efetuado externamento ao forno, o disponilizando mais rapidamente para o início de novo ciclo produtivo. O forno possibilitou a rápida remoção do carvão ainda aquecido, direcionando-o a um container metálico que, por sua vez, promoveu o resfriamento acelerado da carga de carvão produzida. O sistema desenvolvido possibilitou uma diminuição significativa do tempo da carbonização, reduzindo a etapa de resfriamento a apenas 2 horas no interior do forno e 10 horas no container. O carvão produzido apresentou características adequadas tanto para o uso siderúrgico quanto para cocção de alimentos. Além disso, o forno desenvolvido demonstrou melhor desempenho econômico quando comparado ao forno circular de superfície, apresentando viabilidade nos dois cenários analisados.Brazil is the largest producer and consumer of charcoal in the world, however, most of the production is carried out in rudimentary masonry kilns, of small dimensions that generally do not exceed 12m3 of internal volume. These kilns are poorly engineered and use little or no technology, which reflects a productivity below the potential of a very heterogeneous charcoal. In this transformation of the wood into charcoal in the masonry kilns, there is a marked dichotomy in wich, in a first step, heating and retention of the heat is necessary and, subsequently, the dissipation of the energy contained in the system to remove the cargo produced, which ends up raising production time and, consequently, reducing productivity. It is important to emphasize that in this initial phase, the conversion itself, there is little or no margin for reducing time, more subordinate to the characteristics of the raw material, and also aims to ensure the quality of the final product. In this context, the objective of this research was to develop a new masonry experimental kiln for the production of charcoal which contemplates shorter cycles, raising productivity and, simultaneously, ensuring the quality of the charcoal. Thus, the research focus was given to the cooling phase, and strategies were developed to accelerate the cooling of the charcoal, which, in this case, was externalized to the kiln, making it available more quickly for the beginning of a new productive cycle. The kiln allowed the rapid removal of the still heated charcoal, directing it to a metal container which promoted the accelerated cooling of the charcoal produced. The developed system made possible a significant reduction of the carbonization time, reducing the cooling stage to only 2 hours inside the kiln and 10 hours in the metalic container. The charcoal produced had adequate characteristics for both steel use and food cooking. In addition, the developed kiln showed a better economic performance when compared to the circular surface kiln, presenting viability in both analyzed scenarios

Biological resistance of heat-treated wood of "Pinus caribaea" and "Eucalyptus saligna"

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

COMPARISON OF PROCEDURES FOR IMMEDIATE CHEMICAL ANALYSIS OF CHARCOAL

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

Análise de Risco Econômico de Dois Sistemas Produtivos de Carvão Vegetal

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

HIGROSCOPICITY OF CHARCOAL PRODUCED IN DIFFERENT TEMPERATURES

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

Quality of Eucalyptus Wood Grown in Rio de Janeiro State for Bioenergy

ABSTRACT 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