Alternative System for Wood Carbonization / Sistema alternativo de carbonizaÃÃo da madeira

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

The production of charcoal is a activities which depends on the raw material, labor and production system. The raw material needs to possess some characteristics such as, for example, a high lignin content and elevated basic density to warrant an increased production of charcoal. The production system must warrant an adequate working condition seeking to establish strategies for a shorter time of the carbonization cycle without altering the yield and quality of the produced charcoal. This study was intended to test, evaluate and adjust an alternative system for wood carbonization in pilot scale including the construction and test of a prototype. Eucalyptus ssp woods 1,15 m long and diameter ranging from 6 to 15 cm were utilized. In the general evaluation of the system, 12 tests were performed, where the two former served to promote adjustments and changes in the system aiming to improve their performance. After these alterations, four tests were accomplished for corroboration of the efficiency of the modified system. Next, a six-score multichannel temperature measurer with six thermoelectric pairs for the verification of its thermal profile was installed. The analysis of regression was used to study the relationship existing between average internal temperature of the system and the average temperature of the gases eliminated by the chimney. Three models were adjusted, the linear, the cubic and the logarithmic. From the results, it was found that the average cooling times were 10 and 37,5 hours; for the cooling condition inside and outside the isolating unit, a reduction of 73,33 % in the cooling time being observed. The physical yield of the system presented a mean of 4,35 and 2,0 kg/h for the cooling outside and inside the isolating unit, respectively. The average content of fixed carbon, considering only the tests performed with the thermoelectric pairs was of 71,77 %. The estimates of apparent relative density of the coal underwent no significant differences as related to the determination method utilized. The logarithmic method was the one which presented the best adjustment and lowest estimative error of internal temperature of the system as related to the average temperature of the chimney-eliminated gas.

ASSUNTO(S)

vegetal charcoal; wood; eucalyptus ciÃncias agrÃrias carvÃo vegetal; madeira; eucalyptus

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