Analysis of chemical composition and heating value of five oak species for their use as biofuels

Resumen

Objective: To determine the chemical composition and calorific value of biomass from the stump, stem and branches of Quercus calophylla, Q. glaucoides, Q. laurina, Q. magnoliifolia, and Q. rugosa.

Design/methodology/approach: The amount of hemicellulose, cellulose, lignin, and extractable substances was determined in an Ankom fiber analyzer. Pearson’s correlation analysis was conducted between the chemical components, and the higher heating value was also calculated.

Results: The highest values obtained were hemicellulose 14.72% in the branches of Q. laurina; cellulose 67.19% in the stem of Q. calophylla; lignin 21.58% in the stem of Q. rugosa; extractable substances 13.00% in the stump of Q. rugosa. In particular, the correlation between cellulose and hemicellulose was negative (r=-0.80). The results for calorific value varied from 19.32 MJ kg^-1 in the stump of Q. glaucoides to 20.19 MJ kg^-1 in the stem of Q. rugosa.

Limitations on study/implications: The shortage of studies about the chemical composition of wood affects the selection of species for their application in the area of biofuels, and a poor selection of raw material translates into inefficient combustion and greater environmental impact.

Findings/conclusions: The species studied are apt for their use as thickened biofuel, given their chemical characteristics. Q. rugosa presents a higher percentage of lignin content, extractable substances in the stem and the stump, and high heating value , so it is considered to have greater potential for the elaboration of quality pellets.