Allan Motta Couto

Canonical correlations between chemical and energetic characteristics of lignocellulosic wastes.

Canonical correlation analysis is a statistical multivariate procedure that allows analyzing linear correlation that may exist between two groups or sets of variables (X and Y). This paper aimed to provide canonical correlation analysis between a group comprised of lignin and total extractives contents and higher heating value (HHV) with a group of elemental components (carbon, hydrogen, nitrogen and sulfur) for lignocellulosic wastes. The following wastes were used: eucalyptus shavings; pine shavings; red cedar shavings; sugar cane bagasse; residual bamboo cellulose pulp; coffee husk and parchment; maize harvesting wastes; and rice husk. Only the first canonical function was significant, but it presented a low canonical R². High carbon, hydrogen and sulfur contents and low nitrogen contents seem to be related to high total extractives contents of the lignocellulosic wastes. The preliminary results found in this paper indicate that the canonical correlations were not efficient to explain the correlations between the chemical elemental components and lignin contents and higher heating values.

Multivariate analysis applied to evaluation of Eucalyptus clones for bioenergy production

This research aimed to select Eucalyptus clones for bioenergy production by using of two multivariate techniques, principal component analysis and cluster analysis. The analysis evaluated 25 clones of Eucalyptus at age 54 months. Determinations included the concentrations of elemental components (C, H and O), lignin, total extractives and ash, as well as basic density, higher heating value and energy density. Both multivariate methods being used to evaluate and select clones of Eucalyptus for bioenergy production proved effective, there being similarities between the biomass groups formed by them. The cluster analysis revealed five distinct groupings, out of which cluster one, formed by clone U060, was found to have greater potential as a source of energy. Clones G084, G122, G023 and U108 had poorer energy performance.

Mass and energy balance of the carbonization of babassu nutshell as affected by temperature

The objective of this work was to evaluate the carbonization yield of babassu nutshell as affected by final temperature, as well as the energy losses involved in the process. Three layers constituting the babassu nut, that is, the epicarp, mesocarp and endocarp, were used together. The material was carbonized, considering the following final temperatures: 450, 550, 650, 750, and 850oC. The following were evaluated: energy and charcoal yields, pyroligneous liquid, non-condensable gases, and fixed carbon. The use of babassu nutshell can be highly feasible for charcoal production. The yield of charcoal from babassu nutshell carbonization was higher than that reported in the literature for Eucalyptus wood carbonization, considering the final temperature of 450oC. Charcoal and energy yields decreased more sharply at lower temperatures, with a tendency to stabilize at higher temperatures. The energy yields obtained can be considered satisfactory, with losses between 45 and 52% (based on higher heating value) and between 43 and 49% (based on lower heating value) at temperatures ranging from 450 to 850oC, respectively. Yields in fixed carbon and pyroligneous liquid are not affected by the final carbonization temperature.