Insights in quantitative indexes for better grouping and classification of Eucalyptus clones used in combustion and energy cogeneration processes in Brazil

• Published in: Biomass & bioenergy Vol. 143; p. 105835
• Main Authors: Protásio, Thiago de Paula, Scatolino, Mário Vanoli, Lima, Michael Douglas Roque, de Araújo, Ana Clara Caxito, de Figueiredo, Izabel Cristina Rodrigues, Bufalino, Lina, Hein, Paulo Ricardo Gherardi, Trugilho, Paulo Fernando
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-12-2020
• Subjects: Combustion rate; Energy density; Energy forest; Renewable energy; Sustainable management; Sustainable management; Energy density; Combustion rate; Renewable energy; Energy forest
• ISSN: 0961-9534; 1873-2909
• DOI: 10.1016/j.biombioe.2020.105835

The influence of the lignin macromolecule composition, extractives, volatile matter (VM), and fixed carbon (FC) contents on the reactivity and easiness of wood combustion is not fully understood, especially concerning species from fast-growing plantations. This study aims to close this scientific gap revealing the wood chemical composition effects on the combustibility of Eucalyptus clones. Moreover, we proposed new quantitative indexes that allow suitable grouping of genetic materials for energy purposes. The lignin, acetone-soluble extractives, VM, FC, and ash contents, as well as the ratio syringyl (S)/guaiacyl (G), were determined. The thermogravimetric analyses provided the combustion parameters. The characteristics that most contributed to the grouping of Eucalyptus clones were energy productivity (GJ ha−1 and GJ tree−1), energy density (GJ m−3), acetone-soluble extractives (% based on dry mass - db), VM (% db), and the maximum rate of combustion (% min−1). Clones with G units ≤20 g kg−1 db, acetone-soluble extractives ≤1.0% db, and FC ≤ 16% db had easier ignition and better reactivity during the burning. Clones with VM/FC ratio ≥5.0 showed maximum combustion rate ≥8.0% min−1 and acetone-soluble extractives ≤1.1% db. The findings of this investigation are useful to managers’ decision-making and contribute to the selection and rational use of the wood for energy purposes.
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•The acetone-soluble extractives reduced the wood reactivity during the combustion.•Lignins with a higher proportion of guaiacyl units decrease the fuel reactivity.•Slight changes in proximate composition can influence the Eucalyptus combustibility.•The higher volatile matter content is correlated with the better fuel reactivity.•Woods with extractives content ≤1.0% and FC ≤ 16% presented easier ignition.