Hydrothermal Carbonization of Waste Babassu Coconut Biomass for Solid Fuel Production

Different waste biomasses have enormous potential for the production of solid fuel using carbonization techniques to many energy purposes. Synthesis of carbonaceous materials with different morphologies, porosity and chemical composition, using a simple and low-cost technique as hydrothermal carbonization has a huge potential to add value to the production chain of babassu, a regional palm. In this work, two important waste biomasses, derived from babassu coconut, called mesocarp and babassu kernel bran have been used as precursors to produce structured carbonaceous materials via hydrothermal carbonization. The produced hydrochars (HTCs) were characterized and their fuel properties were evaluated. The highest heating value (HHV) revealed values of up to 24.83 MJ/kg for hydrochar from mesocarp and up to 28.91 MJ/kg for hydrochar from babassu kernel bran, showing an increase of 69 % and 89 % of energy yield, respectively, in comparison with the respective precursor waste biomass. Furthermore, the energy density of hydrochars has increased with increasing treatment temperature. The chemical analysis have shown that fuel efficiency of mesocarp hydrochars has improved, such as reduction of ash content, volatile matter and oxygen amount as well as increment of total carbon and fixed carbon content. The evolution of biomass carbonization, as determined by FT-IR and Raman measurements, showed that most carbohydrates and proteins were decomposed at above 160 degrees C. The aromaticity of hydrochars increased with increasing temperature taking into account considerable amounts of functional groups remained in the hydrochars after hydrothermal treatment.