Alexandre Santos Pimenta

Avaliação de duas rotinas de carbonização em fornos retangulares

RESUMO – Este estudo objetivou avaliar o desempenho de fornos retangulares no processo de carbonizacao, envolvendo duas rotinas de carbonizacao. As rotinas analisaram a influencia de tatus e câmaras de combustao externa no processo de carbonizacao em quatro fornos retangulares instrumentados com termopares para acompanhamento da temperatura, bem como o balanco de massa e energia do sistema. A lenha utilizada na carbonizacao foi o clone A08, hibrido do cruzamento entre Eucalyptus grandis e Eucalyptus urophylla, com idade de 7 anos e comprimento da lenha de 3 m. Foram realizadas oito carbonizacoes em cada rotina. De acordo com os resultados, verificou-se que a rotina 2, caracterizada pelo uso das câmaras de combustao externa, foi mais eficiente no controle da carbonizacao; a instrumentacao do forno e uma tecnica viavel, mas que requer ajustes para caracterizar, com precisao, o fenomeno da carbonizacao. No balanco de massa e energia, verificou-se que as perdas foram maiores que os ganhos em producao, para lenha com elevados teores de umidade. Palavras-chave: Fornos retangulares, Carbonizacao de madeira e Producao de carvao vegetal. EVALUTION OF TWO CARBONIZATION ROUTINES IN RECTANGULAR KILNS

Potencial energético da madeira de espécies oriundas de plano de manejo florestal no Estado do Rio Grande do Norte

The objective was to evaluate the energy potential of woods of species under forest management plan from Serido region in the Rio Grande do Norte state. It was used the wood species Jurema Preta, Pereiro, Marmeleiro, Catingueira, Mororo, Imburana, Jurema Branca and Mofumbo, at 20 years old, originated from the Dominga´s farm in the Caico/RN municipality. The density, the content of volatiles, the ash and fixed carbon, calorific value, elemental composition and carbon/nitrogen (C/N) and carbon/ hydrogen (C/H) analysis were carried out in the wood. Additionally, the amount of energy produced in kW.h.m-3 and kW.h.ha-1 for all species was estimated. The experiment was conducted in a completely randomized design with eight treatments (species), four replicates (sample trees), adding up to 32 sampling units. There were significant differences, at 5% significance between treatments for all variables, except for hydrogen percentage and C/H ratio. It was concluded that Mororo´s wood shows high energy potential, and along with Jurema Preta, presents higher energy generation per m3, and provides greater economy for the same productivity. The energy potential Jurema Preta wood´s stands out among the species. Pereiro´s wood stands for energy production per hectare. Marmeleiro and Jurema Branca´s woods are indicated as direct burning potential and Imburana´s wood is not recommended for power generation.

Estudo da decomposição térmica da madeira de oito espécies da região do Seridó, Rio Grande do Norte

RESUMO – Este trabalho teve como objetivo avaliar o perfil de decomposicao termica da madeira de oito especies utilizando as tecnicas de termogravimetria (TGA) e calorimetria diferencial exploratoria (DSC), bem como a consistencia desses metodos para decidir quais especies devem ser indicadas para producao de energia e carvao vegetal, comparando-os com os rendimentos gravimetricos da carbonizacao obtidos a partir de carbonizacoes em mufla de laboratorio. Para as analises por TGA e DSC, amostras de serragem foram aquecidas a taxa de 10 °C min -1 , sob atmosfera de nitrogenio, em vazao de 50 ml min -1 ate a temperatura final de 600 °C. Foram

Antibacterial and antifungal activities of pyroligneous acid from wood of Eucalyptus urograndis and Mimosa tenuiflora

This work aimed to evaluate the antibacterial and antifungal activities of two types of pyroligneous acid (PA) obtained from slow pyrolysis of wood of Mimosa tenuiflora and of a hybrid of Eucalyptus urophylla × Eucalyptus grandis.

BIOMASS AND ENERGY PRODUCTION AT SHORT ROTATION Eucalyptus CLONAL PLANTATIONS DEPLOYED IN RIO GRANDE DO NORTE

1 Received on 08.08.2014 accepted for publication on 30.11.2016. 2 Universidade Federal do Rio Grande do Norte, Unidade Acadêmica Especializada em Ciências Agraria, Macaíba, RN, Brasil . E-mail: <marabio_rn@hotmail.com>,<meire_caico@yahoo.com.br>,<gualtergcs@yahoo.com.br>,<sarahcostaa@yahoo.com.br> and <aspimenta@ufrnet.br>. Universidade Federal de São João Del-Rei, Departamento de Ciências Agrárias, Sete Lagoas, MG, Brasil . E-mail: <castrorvo@ymail.com> and <mendesafn@hotmail.com> 4 Universidade Federal de Viçosa, Departamento de Engenharia Florestal, Viçosa, MG, Brasil . E-mail: <cassiacarneiro@ufv.br>.

CARVÃO VEGETAL COMO CONDICIONADOR DE SOLO NA SUCESSÃO ARROZ E FEIJÃO-CAUPI ADUBADOS COM NITROGÊNIO

The effects of biochar and nitrogen application on yields of upland rice and cowpea and on soil fertility were determined in a greenhouse in Macaíba, RN, Brazil. The trial consisted of the succession of two crops in a completely randomized design and a factorial scheme, with four replicates. Initially, four doses of biochar and four doses of nitrogen were tested for cultivation of rice. Subsequently, four doses of biochar and two doses of nitrogen were tested in half of the pots maintained for planting cowpea. Soil was sampled after rice harvest for half of the pots and at end of the trial for the remaining pots. We evaluated the following parameters: mass of hundred grains of rice, dry shoot mass, panicle number, number of filled spikelets and of empty spikelets, and grain production. Determinations for cowpea were: pod number per pot, grain number per pod, and grain production per pot. Measured soil parameters were: pH, contents of organic carbon, P, K, Ca, Mg, Na, cation exchange capacity, and exchangeable sodium percentage. Biochar addition did not influence yield components of upland rice and cowpea, but resulted in increased soil N retention, which influenced rice dry shoot mass, spikelets sterility, panicle number, and grain mass. Biochar also promoted increased soil pH, potassium content, and exchangeable sodium percentage and decreased calcium and magnesium concentrations.

UTILIZAÇÃO DE RESÍDUOS DE COCO ( Cocos nucifera ) CARBONIZADO PARA A PRODUÇÃO DE BRIQUETES

The present work has the objective to produce briquettes by using fine charcoal from coconut wastes as raw material and evaluate the briquette quality. Coconut piths were collected at the city of Touros, in Rio Grande do Norte state. After a 2- month air drying, coconut pith was carbonized and hereafter ground in a hammer mill. The resulting charcoal powder was sieved and the fraction less than 40 mesh was used to produce briquettes according to an entirely randomized designed experiment involving 12 treatments and 3 replications. Starch and clay were employed as binders. The treatments were divided into 3 groups, each group corresponding to a proportion of clay, respectively 12, 15 and 18%, based on the total dry weight of the briquette. Within each group, the proportions of starch were 6, 8, 10 and 12%. The carbon powder was mixed with finely ground clay was added and then the pre-gelatinized starch in water at 80°C. The mass for each treatment was mixed until homogeneous, separating quantities of 17grams of mass for each repetition. The briquettes were produced in a laboratory press (pressure of1500psi and pressing time of 4 minutes).The briquettes were dried in an oven at 60°C until constant weight. After drying, the properties of briquettes were evaluated: bulk density, high calorific value, immediate chemical composition (moisture content, fixed carbon, volatile matter and ash) and compressive strength. Best treatments for trading products were 12/12 e 12/15.

Chemical Composition of Pyroligneous Acid Obtained from Eucalyptus GG100 Clone

The present study aimed to characterize the chemical composition of pyroligneous acid (PA) obtained from slow pyrolysis of the clone GG100 of Eucalyptus urophylla × Eucalyptus grandis. The efficiency of extraction of organic compounds by using different solvents—dichloromethane (DCM), diethyl ether (DE) and ethyl acetate (EA)—was evaluated. Wood discs were collected and carbonized at a heating rate of 1.25 °C/min until 450 °C. Pyrolysis gases were trapped and condensed, yielding a crude liquid product (CLP), which was refined to obtain pure PA. Then liquid–liquid extraction was carried out. Each extracted fraction was analyzed by GC-MS and the chemical compounds were identified. Experimental results showed that a larger number of chemical compounds could be extracted by using DCM and EA in comparison to diethyl ether DE. A total number of 93 compounds were identified, with phenolic compounds being the major group, followed by aldehydes and ketones, furans, pyrans and esters. Higher contents of guaiacol, phenol, cresols and furfural seem to explain the antibacterial and antifungal activity shown by PA, as reported previously in the literature. Experimental data indicated that the organic phase extracted from GG100 PA consists of a mixture of compounds similar to liquid smokes regularly used in the food industry.

Measurement of Tannic Substances in Forest Species

This study aimed to quantify the tannic content of the barks and fruit of angico-vermelho, jurema-preta and acacia-negra using skin powder as detanizador agent. Materials from these species were ground and classified, with 12.5g of air dried particles subjected to extraction using a steam jacket type extractor to obtain 1000 ml of solution, using a completely randomized analytic design. The solution was evaluated using four treatments: angico bark; jurema bark; acacia bark and angico fruit. Three replicates per treatment were realized and subrepetitions were analyzed in triplicate. The results were interpreted by comparison of means with Tukey test at 5% significance. Best results in terms of total solids content, were observed in acacia bark (67.2%), differing statistically for angico bark (63.5%). The soluble solids content, in turn, was superior to angico bark (60.3%), differing statistically from acacia bark (49.8%). No statistically significant differences for tannin content were observed between acacia and angico barks, which presented values of 28.4 and 26.8%, respectively.

Physico-chemical and energetic evaluation of wood from the species Piptadenia stipulacea (Benth.) Ducke and Amburana cearensis (Allemao) A. C. Smith in a semi-arid region in northeast Brazil.

‘Caatinga’ is an exclusive Brazilian biome, which features a wide variety of fauna and flora, and a good part of these are endemic varieties. Over the years, the abolition of ‘Caatinga’ by human activities has greatly reduced this biome. This fact is mainly due to the use of the energy potential of plant species without proper concern about the sustainability of it. A better understanding of the energy potential of plant species of ‘Caatinga’ enables a more appropriate management. The objective of this study was to evaluate the potential energy and the physical and chemical characteristics of wood species Amburana cearensis (Germans) A. C. Smith and Piptadenia stipulacea (Benth.) Ducke. Five trees of each species were felled, randomly sampled in ‘Sao Bento’ site, located in the city of Patos, Paraiba state. The trees were identified and transported to the Department of Forest Product Technology, Federal University of Campina Grande. From each tree, small discs were removed (5 cm thick) to 0 (base), 25, 50, 75 and 100% of the commercial height of the trunk (up to 5 cm in diameter) and large disks (15 cm thick) before and after each small disk, the small discs were divided into four parts, wedge-shaped, passing through the medulla. Two opposing wedges were used to determine the density and the rest was reserved for the physical and chemical wood analyses and the wood discs were destined for greater achievements of carbonizations. Basic density was determined according to the method of hydrostatic balance and to determine the basic density of each tree used as a weighting factor the volume between sections of each disk. After air drying, the samples for chemical analysis were transformed into sawdust and made quantitative determinations of total extractives, lignin, ash and holocellulose content was estimated by difference from the initial mass [100% (content total extractives + lignin + ash)]. Samples intended for carbonizations were transformed into chips, and charred in an electric furnace (furnace) for 5 hours and 30 minutes. The income from the carbonization products as well as the physical and chemical properties of charcoal were determined. Averages significantly higher than 1% probability of lignin, holocellulose content, total extractives and ash wood were found for the species Amburana cearensis and Piptadenia stipulacea, and this latter had higher average lignin content and holocellulose content. The gravimetric yield was similar for both species, while the condensed liquid yield was significantly higher for Amburana cearensis. In relation to coal quality, higher values were observed for gross calorific value and fixed carbon for Piptadenia stipulacea, while Amburana cearensis exhibited higher levels of volatiles and ash.