Instrumentação térmica aplicada ao processo de produção de carvão vegetal em fornos de alvenaria

Carvalho, Solidônio R.; Borges, Valério Luiz; Mulina, Bruno Henrique Oliveira; Oliveira, Rogério Lima Mota de; Júnior, Edson Alves Figueira; Filho, José Silvio Pessoa

doi:10.1590/s0100-67622012000400020

Cited by 9 publications

(7 citation statements)

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“…Segundo Carvalho et al (2012), esses produtores utilizam fornos de diferentes formatos para produção de carvão vegetal, destacando-se os fornos do tipo "rabo-quente", superfície e encosta. Porém, esses fornos apresentam baixo rendimento gravimétrico e emissões não controladas de gases poluentes para o ambiente.…”

Section: Introductionunclassified

Otimização da produção do carvão vegetal por meio do controle de temperaturas de carbonização

et al. 2013

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RESUMO -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 fornofornalha 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.Palavras-chave: Carbonização de madeira; Fornalha; Forno de superfície; Baixa emissão de fumaça. OPTIMIZATION OF CHARCOAL PRODUCTION THROUGH CONTROL OF CARBONIZATION TEMPERATURES

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Section: Introductionunclassified

Otimização da produção do carvão vegetal por meio do controle de temperaturas de carbonização

et al. 2013

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“…To meet industrial needs, especially the steel industry, forestry companies have sought to achieve greater homogeneity of the raw material by selecting and using species or clones of the genus Eucalyptus (Juízo et al, 2017;Ramos et al ., 2019). Another area of study is the development of kilns and optimizing the wood carbonization process (Carvalho et al, 2012;Oliveira et al, 2015;Carneiro et al, 2018), especially the carbonization temperature.…”

Section: Introductionmentioning

confidence: 99%

“…The carbonization of wood consists of its heating in the controlled presence of oxygen at temperatures above 150°C and results in effective charcoal production at temperatures between 350 and 500 °C (Oliveira et al, 1982). Nevertheless, there is a great variation in the kiln internal temperature during carbonization, presenting higher temperatures in the central and upper regions (Carvalho et al, 2012;Damásio et al, 2015). Thus, controlling the carbonization process based on the internal temperature becomes necessary to increase production and decrease the heterogeneity of charcoal produced in rectangular kilns.…”

Section: Introductionmentioning

confidence: 99%

Carbonization temperature and charcoal properties at different positions in rectangular kiln

Oliveira

Ramos

Pereira

et al. 2020

Agraria

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To increase production and decrease the heterogeneity of charcoal produced in rectangular kilns, the control of carbonization must be carried out based on the kiln internal temperature. The objective of this work was to analyze the maximum carbonization temperature and the time of thermal degradation at temperatures above 290 °C based on the internal kiln wall temperatures, in addition to evaluating charcoal properties in different positions of a rectangular kiln. Wood from the hybrid Eucalyptus urophylla x E. grandis at seven years of age was used for carbonization in rectangular kiln where temperature was monitored and controlled. Process parameters and charcoal quality were evaluated in seven positions in the rectangular kiln. Positions 1 and 7 had higher maximum temperature values and thermal degradation time at temperatures above 290 °C in comparison with the other positions, which presented similar values. There was no significant effect of kiln position on the characteristics of charcoal, which presented average values of 234.61 kg m-3 of bulk density; 55.87% of pieces with size greater than 30 mm; 19.77% of fines (granulometry < 9.5 mm); and 20.80% of friability, 75.39% of fixed carbon, 24.37% of volatile materials, and 0.24% of ash. It was concluded that the kiln position affects the temperature and time of thermal degradation; however, the control of temperature guarantees the production of homogeneous charcoal throughout the kiln, presenting satisfactory quality for steel industry usage.

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“…The domestic charcoal producers, looking for production increase and better product quality, are adopting the best available and accessible technologies in the market, like large dimensions rectangular kilns with mechanized loading and unloading activities (Guimarães Neto et al, 2007;Arruda et al, 2011); carbonization control based on the kiln's internal temperature (Carvalho et al, 2012;Oliveira et al, 2013); and furnaces for the carbonization gases combustion that minimizes the polluting gases emissions to the environment (Cardoso et al, 2010;Costa, 2012).…”

Section: Introductionmentioning

confidence: 99%

Eucalyptus Logs Drying at High Temperatures

et al. 2017

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The objective of this work was to evaluate the drying speed of Eucalyptus urophylla logs in high temperatures and the influence of the presence or absence of bark and also the diameter of the log in the drying rate. Eucalyptus logs 60 cm long were divided into three diameter classes: 8-12 cm; 12,1-16 cm and 16,1-20 cm. The logs were dried in a heater with forced air circulation, in the presence or absence of bark in five temperatures: 50, 75, 100, 125 and 150ºC. The mass and the initial moisture were determined from each log and the water loss was kept up with periodic weightings, closing the drying process when the logs reached 20% moisture. The drying rate of the logs was calculated using the ratio between the total loss of moisture and the time in hours in order to reach the established moisture. It was concluded that the increase in temperature promotes the raise of the drying ratio, as being higher for smaller logs in relation to bigger ones and in addition to this, the bark effect was not significant in the drying of eucalyptus logs above 100ºC. It was also concluded that the best conditions for the operation of artificial dryers for Eucalyptus logs containing bark and separated in diameter classes would be at 125ºC.

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Instrumentação térmica aplicada ao processo de produção de carvão vegetal em fornos de alvenaria

Cited by 9 publications

References 1 publication

Otimização da produção do carvão vegetal por meio do controle de temperaturas de carbonização

Otimização da produção do carvão vegetal por meio do controle de temperaturas de carbonização

Carbonization temperature and charcoal properties at different positions in rectangular kiln

Eucalyptus Logs Drying at High Temperatures

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