Efeito das diferentes temperaturas de carbonização de madeiras para a qualidade do carvão
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Data
2022-05-30
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Universidade Estadual Paulista (Unesp)
Resumo
A madeira é um dos materiais que os humanos utilizam desde os tempos remotos em aplicações que incluem armas, diversos utensílios, habitações e fins energéticos. Possui estrutura elementar composta por carbono, oxigênio e hidrogênio, cujas propriedades oferecem inflamabilidade. A madeira é material higroscópico, constantemente em troca de umidade com meio para se estabilizar, e por não ser ortótropo essas trocas de umidade levam a variações de massa e dentro do PSF a variações dimensionais. O objetivo deste trabalho foi observar a carbonização em várias temperaturas de diferentes espécies de madeira e se possuem relações nas propriedades do carvão como aspectos físicos e químicos, identificando a degradação de forma visual. Dentre as espécies de madeira avaliadas, foram testadas as nativas folhosas Dipteryx sp., Tabebuia sp., Peltogyne sp., Apuleia leiocarpa, Goupia glabra, Astronium lecointei, Hevea brasiliensis e Schizolobium parahyba, Qualea sp. e Aspidosperma sp. e Erisma uncinatum, a nativa conífera Araucaria angustifolia, a exótica conífera Pinus sp. e a exótica folhosa Eucalyptus sp. Com relação aos ensaios realizados para a caracterização do carvão obtido a partir de cada uma dessas espécies, incluem-se os testes de densidade básica, estabilidade dimensional, perda de massa, análise imediata (teores de carbono fixo, de cinzas, de voláteis e de umidade), poder calorífico e degradação visual. A perda de massa e as mudanças dimensionais, em conjunto com a análise visual da presença de fissuras e rompimentos da madeira, pode representar importante característica para o estudo do carvão e o comprometimento da sua qualidade. O comportamento linear decrescente observado no gradiente da densidade básica não foi similar ao encontrado nas análises do poder calorífico, carbono fixo e perda de massa. A carbonização em altas temperaturas não tem correlação em propriedades como densidade e alteração das dimensões da madeira. O poder calorífico é uma propriedade importante na definição da qualidade, porém espécies mais densas em que há maior poder calorífico, demonstrou maiores danos em sua estrutura. Das espécies estudadas, aquelas de menor densidade básica, como: Guapuruvu, Araucária, Pinus e Cedrinho não tiveram avarias ou danos visíveis por meio da análise da degradação visual na temperatura de 300 ºC. Para temperaturas acima desta (400 ºC, 500 ºC e 600 ºC) ocorreram danos em todas as espécies. Ainda que as temperaturas tivessem quatro escalas, o comportamento dessas propriedades se diferenciou entre as espécies para cada uma das carbonizações de 300 ºC, 400 ºC, 500 ºC e 600 ºC, de forma que a taxa de carbonização se mantivesse em média de 20 ºC / min.
Wood is one of the materials that humans have used since ancient times in applications that include weapons, various utensils, housing, and energy purposes. It has an elemental structure composed of carbon, oxygen and hydrogen, whose properties offer flammability. Wood is a hygroscopic material, constantly exchanging moisture with a means to stabilize itself, and as it is not orthotropic, these moisture exchanges lead to mass variations and within the PSF to dimensional variations. The objective of this work was to observe the carbonization in different temperatures of different wood species and if there are relationships in the properties of charcoal as physical and chemical aspects, visually identifying the degradation. Among the species of wood evaluations, were tested as native hardwoods Dipteryx sp., Tabebuia sp., Peltogyne sp., Apuleia leiocarpa, Goupia glabra, Astronium lecointei, Hevea brasiliensis, Schizolobium parahyba, Qualea sp., Aspidosperma sp., Erisma uncinatum, the native coniferous Araucaria angustifolia, the exotic coniferous Pinus sp. and exotic softwood Eucalyptus sp. About the tests carried out for the characterization of the charcoal obtained from each of these species, include tests of basic density, dimensional stability, loss of mass, immediate analysis (contents of fixed carbon, ash, volatiles, and humidity), calorific value and visual degradation. Mass loss and dimensional changes, together with the visual analysis of the presence of cracks and collapses in the wood, may represent an important characteristic for the study of charcoal and the impairment of its quality. The decreasing linear behavior observed in the basic density gradient was not similar to that found in the calorific value, fixed carbon and mass loss analyses. Carbonization at high temperatures has no correlation with properties such as density and changes in wood dimensions. The calorific value is an important property in defining the quality, but denser species in which there is greater calorific value, showed greater damage to its structure. Of the studied species, those with lower basic density, such as: Guapuruvu, Araucaria, Pinus and Cedrinho, did not show damage or damage visible through the analysis of visual degradation at a temperature of 300 ºC. For temperatures above this (400 ºC, 500 ºC and 600 ºC) damage occurred in all species. Even though the temperatures had four scales, the behavior of these properties differed between the species for each of the carbonizations of 300 ºC, 400 ºC, 500 ºC and 600 ºC, so that the carbonization rate remained at an average of 20 ºC / min.
Wood is one of the materials that humans have used since ancient times in applications that include weapons, various utensils, housing, and energy purposes. It has an elemental structure composed of carbon, oxygen and hydrogen, whose properties offer flammability. Wood is a hygroscopic material, constantly exchanging moisture with a means to stabilize itself, and as it is not orthotropic, these moisture exchanges lead to mass variations and within the PSF to dimensional variations. The objective of this work was to observe the carbonization in different temperatures of different wood species and if there are relationships in the properties of charcoal as physical and chemical aspects, visually identifying the degradation. Among the species of wood evaluations, were tested as native hardwoods Dipteryx sp., Tabebuia sp., Peltogyne sp., Apuleia leiocarpa, Goupia glabra, Astronium lecointei, Hevea brasiliensis, Schizolobium parahyba, Qualea sp., Aspidosperma sp., Erisma uncinatum, the native coniferous Araucaria angustifolia, the exotic coniferous Pinus sp. and exotic softwood Eucalyptus sp. About the tests carried out for the characterization of the charcoal obtained from each of these species, include tests of basic density, dimensional stability, loss of mass, immediate analysis (contents of fixed carbon, ash, volatiles, and humidity), calorific value and visual degradation. Mass loss and dimensional changes, together with the visual analysis of the presence of cracks and collapses in the wood, may represent an important characteristic for the study of charcoal and the impairment of its quality. The decreasing linear behavior observed in the basic density gradient was not similar to that found in the calorific value, fixed carbon and mass loss analyses. Carbonization at high temperatures has no correlation with properties such as density and changes in wood dimensions. The calorific value is an important property in defining the quality, but denser species in which there is greater calorific value, showed greater damage to its structure. Of the studied species, those with lower basic density, such as: Guapuruvu, Araucaria, Pinus and Cedrinho, did not show damage or damage visible through the analysis of visual degradation at a temperature of 300 ºC. For temperatures above this (400 ºC, 500 ºC and 600 ºC) damage occurred in all species. Even though the temperatures had four scales, the behavior of these properties differed between the species for each of the carbonizations of 300 ºC, 400 ºC, 500 ºC and 600 ºC, so that the carbonization rate remained at an average of 20 ºC / min.
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qualidade do carvão, madeira carbonizada, gradiente de densidade, propriedades física e química, physical and chemical properties, coal quality, charred wood, density gradient