Effect of Plant Part and Age on the Proximate, Chemical, and Elemental Characteristics of Elephant Grass Cultivar BRS Capiaçu for Combustion-Based Sustainable Bioenergy

Elephant grass is an outstanding crop biomass for sustainable energy generation. Here, the effect of plant parts (stem, leaf, and whole plant) at four ages (90, 120, 150, and 180 days) on the proximate, chemical, and elemental characteristics of elephant grass cultivar BRS Capiaçu is investigated. From proximate analysis, the heating value is dependent on the water content regardless of plant part and age. A linear model allowing the prediction of heating value solely based on water content is derived from measurements. Density is modelled as a quadratic function of water content across ages and plant parts. Such a model can be used to predict the moisture-dependent weight of the biomass and its parts. Cellulose content is at the upper bound of benchmark values found in the literature. The highest lignin content, which tends to increase with age, is found in the stem. From elemental analysis, a much higher mineral content increasing with age is produced by the leaf. Contrarily, significantly lower mineral content is generated by the stem, bottoming out at 180 days. This is reflected in five predictive indices for slagging and fouling, which suggest that the stem at 180 days is the optimal part and age for energy purposes.