Quality of charcoal produced from coffee wood for bioenergy use.

Abstract

The objective of this study was to evaluate the quality of charcoal from Coffea arabica L., for bioenergy purposes, using three existing cultivation systems in the South of Minas Gerais (natural agroforestry, organic and conventional) and two cultivars (Mundo Novo and Catuai). Univariate and multivariate statistical techniques were used, besides the identification of mineral components for the selection and evaluation of the quality from coffee charcoal. The following properties were quantified in charcoal: apparent relative density, actual relative density, immediate chemical composition (volatiles, ash and fixed carbon), fixed carbon stock, energy densities, porosity, heating values; besides carbonization yields. The charcoal of the cultivar Catuai, with organic and conventional systems, stood out for steel and energy use, mainly by the higher values of apparent relative density, energy densities, fixed carbon stock and yields in charcoal and in fixed carbon. The effect of cultivar on apparent relative density was responsible for the formation of a similar group between the wood charcoal from organic and conventional systems for cultivar Catuai. Coffee charcoal from the conventional system showed the best K/Ca ratio. It is therefore best suited to be used as fuel in boilers, gasifiers and other energy conversion systems.