Comparison of the quality of buriti (Mauritia flexuosa L. f.) petiole tissues for combustion and carbonization

Abstract

Despite its social, cultural and economic importance for the Amazon region, the energy potential of Mauritia flexuosa, popularly known as buriti, has not yet been explored in order to expand the possible uses of this species by the local communities. Therefore, the aim of this work was to compare the tissues that comprise the petiole of Mauritia flexuosa for combustion and carbonization. The petiole core and bark were separated and characterized by chemical composition (total and water-soluble extractives, lignin, and ashes), moisture content (based humid mass), proximate composition (contents of volatile matter, fixed carbon, and ash), basic density, higher heating value, and thermogravimetric analysis in N₂ inert atmosphere. The two tissues from the Mauritia flexuosa petiole presented advantages for bioenergetic purposes, such as low ash content (≤ 2%) and higher heating value (≈ 18 MJ kg^-1), in addition to suitable fixed carbon (≈ 18%). For the core and husk, the lignin contents (19 and 28%, respectively), extractives contents (9 and 5%, respectively), and basic density (0.041 and 0.267 g cm^-3, respectively) significantly differed. However, the proximate composition of the tissues was not influenced by such differences, unlike the higher heating value and energy density. The thermogravimetric behavior showed higher degradation ratio and lower final mass yield (7%) for the core in comparison to the husk. The husk showed better quality for combustion and carbonization in comparison to the core. This is an advantageous result for the extractive activities of Amazonian communities because the husk is a waste from the petiole processing in order to obtain the core for handcraft. Due to the low basic density, the core can be noted for its use in torrefaction, densification, pyrolysis for the production of bio-oil and production of natural filters and activated charcoals, rather than direct combustion and carbonization.

Keywords:
Heating value; Energy density; Thermal degradation