The present work aimed to compare the energy potential of residues generated in the processing of coffee beans (Coffea canephora Pierre ex A. Froehner, var. Conilon) and in the wood milling process, suggesting their use as a replacement for eucalyptus firewood in the drying process of coffee beans. The use of agricultural and forestry waste could help reduce environmental problems related to contamination of soil, air and water due to inadequate disposal, and reduce the cost of production and or processing of coffee. By-products of dry distillation and charcoal of these raw materials were quantified and compared. According to the results, it was verified that the residue of coffee hulls provided an exceptional charcoal production, in which the charcoal generated was statistically predominant. Considering the yield and quality of charcoal, the best result was obtained by carbonization of coffee hulls at temperatures of 350°C and 550ºC and the residues of milling at 550°C, mainly due to average yields on fixed carbon. In such cases, these results exceeded those given by charcoal produced derived from wood of eucalyptus. In regards to the calorific value, it was found that residues from wood and coffee hulls could be used for drying coffee beans, since they have similar values to that of eucalyptus. Due to the high charcoal and fixed carbon yields, the charcoals produced from the processing of coffee beans and the wood milling process showed considerable potential for use as an energy source.
Lignocellulosic residues; pyrolysis; charcoal
