Density Of Charcoal Research Articles

Analisa Kualitas Briket Arang dari Cangkang Kelapa Sawit Dengan Rasio Perekat Amylum dan Ukuran Partikel Terhadap Parameter Produk Briket

One solution to reduce kerosene consumption is by utilizing waste from palm kernel processing to create biochar briquettes. These biochar briquettes are made from palm kernel shells and serve as a dense alternative energy source. Additionally, biomass charcoal can also be used as an alternative fuel. Biomass charcoal has a high calorific value and produces minimal smoke and emissions when burned. Various biomass materials, including palm kernel shells, wood, and coconut husks, can be used. The study aims to determine the burnable surface area of briquettes within a specific time frame. Particle size and adhesive percentage affect the charcoal density on the briquette surface, which, in turn, influences combustion speed. The results indicate that the burnable surface area of the samples is quite small. Furthermore, the study measures the ignition time required for briquettes to burn completely. On average, the samples burn for 90 to 114 minutes. Although there is no significant difference in burn time between mesh sizes 40, 50, and 60, the reference sample burns for up to 3.5 hours.

Energy characterization of wood and charcoal from Savannah forest species

The objective of this study was to evaluate the energy potential of Astronium fraxinifolium and Enterolobium gummiferum wood species that grow in the Savannah of Minas Gerais, Brazil, focusing on the production of charcoal. Two discs were removed at 1.30 m from the ground of three trees of each species, and these were later sampled into wedges that were applied in the analysis of wood characteristics and charcoal production in a muffle furnace. The extractives content and basic density of the wood species were determined, and apparent density of charcoal, ash content, heating value, and energy density of both materials were also determined. The woods under study have potential for application in energy production. Emphasis was placed on A. fraxinifolium, which presented wood and charcoal that was denser, had higher energy density, and achieved greater gravimetric yield.

Investigation of Acoustic Efficiency of Wood Charcoal in Impedance Tube for Usage in Sound-Reflective Devices

Charcoal is an environmentally friendly, biodegradable, and economical material. This material is usually produced by slow pyrolysis—the heating of wood or other substances in the absence of oxygen. The aim of this study was to investigate the acoustic efficiency of charcoal and design an acoustic diffuser that utilizes charcoal. Samples of different types of tree charcoal—birch (Betula pendula), pine (Pinus sylvestris), and oak (Quercus robur)—with different thicknesses were used for the acoustic efficiency measurements. The sound absorption and sound reflection properties of charcoal were investigated. The bulk density of charcoal was measured. In this study, an impedance tube with two microphones was employed as the measurement method. The results of the impedance tube measurements showed that the charcoal samples had high sound reflection coefficients, the highest value of which was 1. The 50 mm samples of birch had a high bulk density of 473 kg/m3. The sample of 50 mm thick oak had the best reflection coefficient at 0.99. Reflection depended on the surface’s acoustic properties, and the sound reflection coefficient increased with the increase in the density. Charcoal measurements, due to the high reflection coefficient of the material, were used for the design of a sound diffuser, which included wooden perforated plates filled with cylindrical elements of wood charcoal.

Clarifying the carbonization temperature effects on the production and apparent density of charcoal derived from Amazonia wood wastes

Controlling the carbonization process in brick kilns based on temperature and selecting raw material to reduce heterogeneity are key challenges in producing high-quality charcoal from Amazonia wood wastes. The study's main objective was to investigate how the final carbonization temperature and different Amazonian wood species affect the carbonization efficiency and the charcoal apparent density (CAD). After determining wood basic density (WBD), the wastes underwent carbonization on a laboratory scale at four final temperatures (400, 500, 600, and 700 °C). The gravimetric yield in charcoal (GYC), the specific consumption of firewood (SCF), and the CAD were evaluated. The CAD ranged from 0.248 (T. guianensis) to 0.656 g cm−3 (Licania sp.) and showed a positive correlation with WBD at all temperatures (400 °C - r = 0.954, 500 °C - r = 0.944, 600 °C - r = 0.930, and 700 °C - r = 0.927). Wastes from the species P. suaveolens and D. excelsa showed the highest mean values of GYC regardless of the carbonization temperature. The increase in the final carbonization temperature from 400° to 700°C reduced the GYC and increased the SCF and CAD. The species T. guianensis (25.6%), Manilkara sp. (25.4%), and D. excelsa (24.7%) showed more significant reductions in GYC from 400° to 700°C. Thus, temperatures below 500 °C are recommended for charcoal production from Amazonia wood wastes to provide better carbonization performance. In our study, charcoals from Licania sp., D. excelsa, and Manilkara sp. were the densest and, therefore, most suitable for the steel industry.

Carbonization of Coconut Shell Biomass in a Downdraft Reactor: Effect of Temperature on the Charcoal Properties

Considering the value of coconut shell biomass as renewable fuels in homes and commercial industries, its effectiveness as a biomass resource has been overlooked by our rural citizens and researchers. Carbonization experiments of coconut shell biomass were conducted in a downdraft carbonization reactor (750 mm height and 67 mm diameter) to determine the effect of temperature (250 to 600 °C, in 50 °C intervals) on the charcoal properties. This was to address the problems of traditional charcoal production methods that include; low yield, environmental pollution, unregulated temperature, and poor quality properties. Yet the scarcity of this information hampers efforts for efficient commercial production. The coconut shell biomass was obtained from a local shop in Malaysia. It was heated in the reactor at a fixed residence time of 60 min and a particle size of 5 mm with nitrogen as a carrier gas. The relationship between temperature and the properties of coconut shell charcoal has been ascertained by the findings of this analysis. The relatively high the temperature, the better the charcoal quality, but the lowest the charcoal yields, since the secondary pyrolysis reaction expends charcoal. It was noted that, up to a final temperature of 500 °C, the yield reduction was rapid; after that, it was slower at 550 °C and almost stable at 600 °C. According to the charcoal’s proximate analysis, the calorific value, fixed carbon content, carbon content and ash content increased with temperature. Whereas, the charcoal density, volatile matter, moisture content, and conversion efficiencies decrease with temperature. The presence of nitrogen gas appears to have reduced combustion reactions that promote the formation of carbon dioxide (CO2). The methods produce the least amount of air pollutants (96 g carbon monoxide (CO), 167 g CO2, and 64 g methane (CH4) per 1 kg of charcoal production). The type of biomass and carbonization kiln has an impact on the production of CO, CO2, and CH4. Thus, the carbonization reactor used in this study has the potentials to produce an eco-friendly charcoal with superior quality properties that can assist in reducing environmental pollution, by proper selections of carbonization temperature.

Experimental investigation of humidification parameters using biomass-based charcoal as an alternative packing material

Due to the increase in human population, there is an ever-increasing demand for energy in different sectors which leads to environmental problems like climate change, rise in temperature, and global catastrophes. Cooling systems have become a very essential element in recent decades for mankind. The present system focuses on the design and fabrication of a counter-flow humidification setup which uses biomass-based charcoal as the packing material. Air velocity and water flow rate have been varied along with the density of charcoal. Output parameters such as a change in pressure (ΔP), Coefficient of performance (COP), evaporation rate (ER), humidification efficiency (HE), specific cooling capacity (SCC), and energy consumption (EC) are evaluated. Performance parameters obtained for charcoal are compared with that of standard Celdek Packing. Through experiments, it is found that humidification efficiencies for Celdek and charcoal packing are 77.45% and 57.40% respectively. The overall coefficient of performance obtained is 1.41 for charcoal and 3.17 for Celdek packing. Among the three densities which were considered, charcoal packing with a density of 400 kg/m3 exhibited higher performance with respect to COP, HE, ER, and SCC. Similarly, a water flow rate of 0.4 lpm gave a maximum performance and 0.7 lpm gave the least. It is concluded that charcoal can be considered one of the highly efficient biomass-based materials contributing to sustainable energy related to cooling applications.

Revisiting climate change and palaeoenvironments in the Purbeck Limestone Group (Tithonian – Berriasian) of Durlston Bay, southern UK

Durlston Bay in Dorset, southern UK, type section of the Tithonian-Berriasian Purbeck Limestone Group, has been intensely studied with regard to its marginal marine palaeoenvironments, rich fossil biota and evidence for earliest Cretaceous climate change. Here we appraise aspects of these topics, incorporating new field observations. We offer changes in charcoal density as a further line of support for a mid-Berriasian moistening of the climate, but suggest that the primary driver of palaeoenvironmental and biotic changes observed through the Purbeck succession was varying input of marine water, with climate change having an overlying and often more subtle influence.

Life Cycle Assessment of Renewable Reductants in the Ferromanganese Alloy Production: A Review

This study examined the literature on life cycle assessment on the ferromanganese alloy production route. The environmental impacts of raw material acquisition through the production of carbon reductants to the production of ferromanganese alloys were examined and compared. The transition from the current fossil fuel-based production to a more sustainable production route was reviewed. Besides the environmental impact, policy and socioeconomic impacts were considered due to evaluation course of differences in the production routes. Charcoal has the potential to substantially replace fossil fuel reductants in the upcoming decades. The environmental impact from current ferromanganese alloy production can be reduced by ≥20% by the charcoal produced in slow pyrolysis kilns, which can be further reduced by ≥50% for a sustainable production in high-efficient retorts. Certificated biomass can ensure a sustainable growth to avoid deforestation and acidification of the environment. Although greenhouse gas emissions from transport are low for the ferromanganese alloy production, they may increase due to the low bulk density of charcoal and the decentralized production of biomass. However, centralized charcoal retorts can provide additional by-products or biofuel and ensure better product quality for the industrial application. Further upgrading of charcoal can finally result in a CO2 neutral ferromanganese alloy production for the renewable power supply.

STUDY OF THE INFLUENCE OF WOOD PROPERTIES ON THE CHARCOAL PRODUCTION: APPLYING THE RANDOM FOREST ALGORITHM

ABSTRACT The understanding of the relationship between the properties of wood and charcoal makes it possible to improve the production of charcoal. Therefore, the random forest algorithm was used in this study to analyze the influence of eucalyptus wood properties on the quality of charcoal as well as the accuracy of the predicted values concerning the results estimated by support vector regression and multiple linear regression. Six properties of wood and six properties of charcoal obtained from the hybrid Eucalyptus grandis x Eucalyptus urophylla and from twelve clones of Corymbia torelliana x Corymbia critriodora at the age of seven were measured. In the analysis, the measure of mean decrease in node impurity (residual sum of squares) calculated with the random forest and the copula correlation was used to evaluate the relationship between properties of wood and charcoal. The random forest was compared to the support vector regression and multiple linear regression through the coefficient of determination, linear correlation between observed and predicted values, mean absolute error and root mean squared error. The accuracy of the random forest was greater than that obtained with the support vector regression and multiple linear regression, mainly in terms of the coefficient of determination and the linear correlation between observed and predicted values. The yield and quality of the charcoal produced from clones were mainly influenced by the holocellulose content, heartwood/sapwood ratio, and basic wood density. The apparent relative density of charcoal was the variable in which the random forest algorithm reached the best level of explanation of the variability as a function of the properties of wood, while the minor error was observed for the fixed carbon content.

Potencial do uso de quatro espécies de bambu para a produção de carvão vegetal para uso doméstico

A utilização de colmos de bambu pode ser uma importante alternativa de ampliação das fontes renováveis para a produção de bioenergia, inclusive para a produção de carvão. Assim, o objetivo deste trabalho foi avaliar o potencial de quatro espécies de bambu para a produção de carvão vegetal para uso doméstico, como forma de promoção do uso múltiplo desta matéria-prima e para geração de renda adicional para os agricultores familiares de Santa Catarina. Foram analisados cinco indivíduos das espécies Bambusa vulgaris, coletada em Florianópolis, e Phyllostachys bambusoides; Phyllostachys edulis e Phyllostachys nigra coletadas no município de Frei Rogério, Santa Catarina. As análises da massa específica básica dos colmos in natura, as propriedades físicas, rendimento da carbonização e propriedades energéticas do carvão foram realizadas nas porções basal, mediana e topo dos colmos de bambu de cada espécie. A qualidade do carvão vegetal variou entre as espécies de bambu, tendo como único ponto negativo o alto teor de cinzas para uso doméstico do carvão vegetal. Houve alta correlação positiva entre a densidade básica dos colmos e a densidade relativa aparente do carvão vegetal. A espécie Bambusa vulgaris apresentou o maior rendimento no processo produtivo, porém gerou carvão mais leve e com pior desempenho energético. Entre as espécies avaliadas, Phyllostachys nigra foi a espécie que produziu o carvão vegetal com a melhor qualidade energética e com boas propriedades físicas e rendimento gravimétrico. A qualidade do carvão vegetal variou em relação à altura do colmo. O topo dos colmos, que é o resíduo que pode ser destinado para a produção de carvão em plantios comerciais de bambu para múltiplos usos, apresentou maior rendimento no processo produtivo e carvão com maior densidade. Porém a qualidade energética do carvão foi inferior em relação a base e posição mediana dos colmos.

Investigating the pyrolysis temperature to define the use of charcoal

The production of charcoal for its many uses requires a careful selection of biomass and pyrolysis conditions, especially temperature, to ensure suitable quality. To do so, physical, chemical, and mechanical energy must be considered. This study aimed to analyze the yields and properties of charcoal produced at different pyrolysis temperatures. Eucalyptus saligna wood was pyrolyzed in a reactor with final temperatures of 450, 550, 650, 750, 850 and 950 °C. The yields of charcoal, pyroligneous liquid and non-condensable gases were determined. Mass loss was determined for each temperature. Charcoal analysis included the determination of the apparent density, proximate analysis, heating value, mechanical strength, X-ray images for the internal visualization of its structure and hygroscopicity test. Relevant charcoal properties for the steel industry and barbecue, such as density, mechanical strength, heating value and hygroscopicity, show variable trends from pyrolysis at 650 °C. The results show that pyrolysis temperature had a great impact on the properties of charcoal. The apparent density of charcoal rose from 500 °C and had no relation to the breaking strength. When the pyrolysis temperature was raised, an increase in both apparent and true densities, internal fissures and cracks and fixed carbon content of charcoal was observed.

Biomassa de espécies florestais para produção de carvão vegetal

Devido à alta demanda das empresas por geração de energia oriunda de fontes renováveis, o objetivo deste estudo foi analisar as propriedades da madeira e do carvão proveniente de três espécies florestais: Ceiba pentandra (L.) Gaertn. (Sumaúma), Guatteria sp. (Envirão) e Brosimum sp. (Mumuré). O material foi coletado na Empresa Rosa Madeireira Ltda. De cada espécie foram coletadas 10 amostras para a análise das propriedades da madeira e do carvão e, destas, 5 amostras foram utilizadas para a análise química. As propriedades avaliadas foram: densidade básica e teor de umidade da madeira, rendimento gravimétrico, densidade aparente e teor de umidade do carvão e, composição química. Os dados foram submetidos à Análise de Variância e médias comparadas pelo teste Tukey a 5% de probabilidade, assim como os efeitos da densidade básica sobre o rendimento gravimétrico e sobre a densidade aparente foram testados pela correlação de Pearson. As análises indicaram que o fator espécies apresentou efeito significativo em todos os parâmetros, exceto quanto ao teor de umidade do carvão. Sobre densidade básica da madeira, a Sumaúma apresentou o menor valor médio (0,4302 ± 0,0157 g/cm3) e Mumuré, o maior (0,5276 ± 0,0251 g/cm3). Entretanto, com relação ao teor de umidade, Sumaúma foi a espécie que apresentou o maior teor (47,46% ± 2,88). Os valores de rendimento em carvão variaram entre 30,03% ± 1,95 (Envirão) e 32,35% ± 1,46 (Sumaúma). Houve correlação entre a densidade da madeira e o rendimento gravimétrico para a espécie Mumuré (P = -0,553), no entanto, considerada negativa. Entretanto, correlação positiva foi encontrada para Sumaúma (P = 0,058) e Envirão (P = 0,955). Nos testes de densidade do carvão, o Mumuré apresentou o maior valor médio (0,3173 ± 0,0116 g/cm3) e Envirão o menor (0,2654 ± 0,0407 g/cm3). Uma relação direta e positiva entre a densidade básica da madeira e a densidade relativa aparente do carvão foi encontrada. Tratando-se da composição química, o fator espécies não apresentou efeito significativo.

Context and contents: Distinguishing variation in archaeobotanical assemblage formation processes at Early Halaf Fistıklı Höyük, Turkey

Meaningful interpretation of archaeobotanical assemblages in the Near East often includes determination of whether dung fuel is the source of some or all of the recovered plant remains. In the years since Miller (Economy and Environment of Malyan, a Third Millennium B.C. Urban Center in Southern Iran. Ph.D. Dissertation, Department of Anthropology, University of Michigan, Ann Arbor, 1982; Paleorient 10:71–79, 1984) and Miller and Smart (J Ethnobiol 4:15–28, 1984) first identified archaeological plant remains from Malyan (Iran) as those of burned dung, subsequent archaeobotanical, experimental, and ethnographic research has been undertaken to test and expand her criteria for its recognition. A key criterion of Miller’s was a high ratio of weed seeds to wood charcoal (or a low ratio of charcoal to weed seeds). When used together with other quantitative measures based on standardizing ratios, this measure can help to illuminate variability in the sources of the recovered carbonized plant remains and some of the taphonomic processes that contributed to the resulting assemblage. Using the Late Early Halaf dataset from Fistikli Hoyuk, Turkey, as a case study, non-parametric statistical analysis was applied to eight such measures, including a new Fragmentation Index (FI), density measures (per litre of sediment) for charcoal, cereal grains, weed seeds, chaff, non-wood items, and cereal-type indeterminate non-wood items, and a relative density measure of charcoal to weed seeds. Each measure was calculated on the basis of 35 samples (n = 8,532). The results of this analysis indicate that these measures, when used in combination with Miller’s weed seed to charcoal ratio, implemented here as the relative density of charcoal to weed seeds, can reveal recovery context-related variations in formation processes that help to clarify both the role of dung fuel in assemblage formation and to differentiate the remains of cereal processing from those of burned fuel.

Comparison study of efficiency and property of fuel briquette by electrical machine by motor and hand machine using bicycle

Comparison study of efficiency and property of charcoal briquette by using electrical motor machine and bicycle machine was done. The size of electrical motor was 3.5 horsepower and wooden charcoal is grinded crushing machinery was used. The components were grinded charcoal 2,000 g: tapioca flour 500 g (ratio 4:1) and water. They were brought to grind by crushing machinery by using electrical motor and bicycle machine. The times were recorded and brought the charcoal to dry in the sun to get rid of moist. The heat energy was tested by using machine Cal 2k e2k (Bomb Calorimeter) and found mechanical properties of physics which was density of charcoal by calculating from ratio between mass of charcoal briquette per capacity of charcoal briquette. Moreover, the time of lighting fire was found and time of burning was also found by lighting and recorded time until charcoal was burnt. The result of research was found that working efficiency of charcoal briquette by using electrical motor machine took time for grinding average 4.29 minutes and using bicycle machine took time for grinding average 4.50 minutes. The time of grinding was different 4.79%. The value of heat of using electrical motor machine and using bicycle machine was 22.68 MJ/kg and 23.34 MJ/kg respectively. The value of heat was different 2.87%. The values of density were 907.43 kg/m3 and 838.57 kg/m3 respectively. The values of density were different 7.89%. Moreover, the times of lighting were average 6 minutes and 4.33 minutes respectively. The times of lighting were different 32.33%. The times of burning were average 5.17 hours and 4.24 hours respectively. The times of burning were different 19.76%

Influence of Wood Physical Properties on Charcoal from Eucalyptus spp.

ABSTRACT The use of wood in the form of charcoal for energy production, has great economic importance in Brazil. In this context, the study of variables and mechanisms that affect charcoal quality is essential. The present study aimed to verify the influence of some physical properties of Eucalyptus wood on the quality and yield of the produced bioreducer. We used three commercial Eucalyptus clones, cultivated for use in the steel industry, determining wood density and shrinkage, density and immediate chemistry of the charcoal produced and the charcoal gravimetric yield. The data was submitted to Pearson’s correlation analysis. Correlations between wood density and apparent charcoal density as well as charcoal ash content were observed. All clones presented characteristics suitable for the production of charcoal for the steel industry, with emphasis on the hybrid E. urophylla x E. grandis.

CARACTERÍSTICAS ENERGÉTICAS DO CARVÃO VEGETAL DE AROEIRA (<i>Myracrodruon urundeuva </i>Allemão) E LEUCENA (<i>Leucaena leucocephala </i>(Lam.) R. de Wit)

A exploração de madeira com finalidade energética (lenha e carvão) vem provocando redução na vegetação nativa, agregado a isto, problemas são gerados para fauna, flora e solo. O objetivo da pesquisa foi avaliar as características energéticas do carvão vegetal de aroeira (Myracrodruon urundeuva Allemão) e leucena (Leucaena leucocephala (Lam.) R. de Wit). Foi realizada a supressão de cinco exemplares de Myracrodruon urundeuva e Leucaena leucocephala, seguindo-se critérios de qualidade fenológica e de sanidade. A carbonização foi realizada em duplicata, utilizando a madeira anidra. Também foi realizada análise química imediata do carvão, determinação da densidade verdadeira e densidade aparente. O poder calorífico superior foi determinado por meio de calorímetro adiabático. O experimento foi arranjado em delineamento inteiramente casualizado (DIC), e os valores foram submetidos à análise de variância pelo teste “F” em nível de 5% de probabilidade de erro. A madeira de Myracrodruon urundeuva e Leucaena leucocephala apresentaram rendimento sem diferenças estatísticas, com 41,22% e 40,59% de carvão. A densidade aparente do carvão da madeira de Myracrodruon urundeuva (0,59 g/cm3) foi maior que a de Leucaena leucocephala (0,39 g/cm3), porém, as espécies mostraram-se semelhantes para a densidade verdadeira do carvão, com 1,21 g/cm3 e 1,11 g/cm3, respectivamente. Da mesma forma, o poder calorífico superior do carvão não apresentou diferença entre as madeiras das espécies, Myracrodruon urundeuva (6.869 kcal/kg) e Leucaena leucocephala (6977 kcal/kg). A quantidade de materiais voláteis liberados e de cinzas produzidas foi superior na madeira de Myracrodruon urundeuva, com 33,87% e 3,79%. Já o teor de carbono fixo foi maior na Leucaena leucocephala (67,15%). As espécies estudadas apresentaram características energéticas semelhantes, portanto, a madeira de Leucaena leucocephala pode ser utilizada para produção e utilização do carvão vegetal quando comparadas as espécies nativas já conhecidas e usadas para os mesmos fins.

CHARACTERIZATION AND STATISTICAL CORRELATION BETWEEN CHARCOAL’S PHYSICAL AND MECHANICAL PROPERTIES OF <i>Eucalyptus</i> AND <i>Corymbia</i> CLONES

The study aimed to analyze the physical and mechanical properties of charcoal from eucalyptus clones by principal component analysis and demonstrate the relationships between these properties, in order to assess which charcoal property should aimed in the process to obtain a higher quality product. In this way, was cut eight clones of Eucalyptus and two of Corymbia, collecting three trees per clone and five disk in different heights. The disks were transformed into test samples, totaling an average of 75 samples per clones, which were carbonized under specific conditions for analysis of apparent density, compressive strength parallel to grain and linear and volumetric degradation due to high temperature. It is noteworthy that the data were weighted by disk and per tree, to an average closer to reality. For correlations, was used multivariate analysis of principal components. Herein, it is found that the apparent density of charcoal acts as the focal point of the other properties studied, and observed that as the higher the density, higher will be the compressive strength parallel to grain, the elastic modulus and the gravimetric yield.

Effect of environmental exposure on charcoal density and porosity in a boreal forest

Although charcoal's density and porosity shape its environmental roles (e.g. controlling its landscape movement and determining the internal pore space available as microbial habitat), the rate of change of these properties in the environment remains largely unknown. With time, charcoal pores may fill or charcoal particles may shatter, altering the ecosystem services delivered. In this study we examined the effects of environmental exposure on the density and porosity of charcoals pyrolyzed at two different temperatures (350 and 520°C). Fresh charcoal made from the dominant local tree (Pinus sylvestris) was returned in litter incubations to Norwegian boreal forest soils for 20months in three different placements: (i) aboveground, (ii) in the humus layer, and (iii) under the humus layer in contact with the mineral subsoil. By varying soil horizon placement we were able to separate the effects of infill from the effects of environmental disturbance on charcoal density and porosity.Environmental exposure changed charcoal density and porosity, and the response varied with environmental placement. Charcoal placed in soil layers increased in porosity by ~1–2% after 20months' incubation. This is likely because open indentations on the charcoal surface became partially occluded, creating more detectable pore space. In contrast, the porosity of charcoal incubated aboveground decreased slightly (~1–2% over 20months). Because there were no minerals or humic substances to infill the aboveground charcoal samples, this porosity reduction was likely caused by breakage of particles induced by weathering. When charcoal particles cleave through pores, internal pore space is destroyed.The small changes observed here indicate that environmental exposure did not trigger rapid shifts in charcoal density and porosity. In addition, these physical properties appear not to have reached equilibrium after 20months incubation, suggesting that the effect of environmental exposure on charcoal's physical properties occurs on the timescale of years to decades.

EFEITO DA CARBONIZAÇÃO DA MADEIRA NA ESTRUTURA ANATÔMICA E DENSIDADE DO CARVÃO VEGETAL DE <i>Eucalyptus

O presente trabalho objetivou avaliar as modificações anatômicas que ocorrem com a carbonização da madeira e determinar as propriedades anatômicas, densidade básica da madeira e densidade aparente do carvão vegetal de clones de Eucalyptus, além de elucidar as possíveis correlações significativas existentes. A microscopia eletrônica de varredura foi efetuada nas seções transversal, longitudinal tangencial e longitudinal radial da madeira e do carvão vegetal. Neste, foi feita a análise morfológica dos poros e densidade aparente. De uma forma geral, as características anatômicas como forma de poros, raios e fibras da madeira apresentaram pouca ou nenhuma modificação devido à carbonização, e a superfície do carvão apresentou estruturas bem definidas. As modificações nos elementos celulares da madeira foram principalmente referentes aos parâmetros quantitativos, como espessura da parede das fibras e diâmetro dos poros. Os clones avaliados apresentaram densidade básica da madeira satisfatória para a produção de carvão vegetal. Os parâmetros anatômicos correlacionaram-se significativamente com a densidade básica da madeira e densidade aparente do carvão vegetal, destacando-se, neste estudo, a fração parede das fibras.

INFLUÊNCIA DAS PROPRIEDADES QUÍMICAS E DA RELAÇÃO SIRINGIL/GUAIACIL DA MADEIRA DE EUCALIPTO NA PRODUÇÃO DE CARVÃO VEGETAL

O trabalho teve como objetivo determinar a influência das propriedades químicas (composição elementar, teores de extrativos totais, lignina total e holocelulose) e relação siringil/guaiacil, da madeira de diferentes materiais genéticos de eucalipto na produção de carvão vegetal. Utilizaram-se na pesquisa quatro clones híbridos de Eucalyptus, aos 7 anos de idade, sendo 6 árvores por clone, totalizando 24 unidades amostrais. Houve diferença significativa, a 5% de significância, entre os tratamentos para a composição elementar, teores de extrativos totais, lignina total e holocelulose e relação siringil/guaiacil da madeira, como também, para os rendimentos gravimétricos em carvão vegetal, em gases condensáveis e em gases não condensáveis, teores de carbono fixo e de materiais voláteis e para o poder calorífico superior do carvão vegetal. Para o teor de cinzas e densidade relativa aparente do carvão não foram observadas diferenças significativas ao mesmo nível de significância. Concluiu-se que existe variabilidade na qualidade da madeira dos quatro materiais genéticos avaliados, tendo, os mesmos, correlações distintas, tanto no rendimento quanto na qualidade do carvão vegetal. Todos os materiais genéticos apresentaram, de modo satisfatório, rendimento gravimétrico em carvão vegetal e qualidade. As madeiras dos clones com baixa relação siringil/guaiacil apresentaram aumento no rendimento em carvão vegetal. A composição química das madeiras dos quatro clones, de modo geral, não apresentou correlações significativas, a 5% de significância, no rendimento e qualidade do carvão.