Prediction models based on higher heating value from the elemental analysis of neem, mango, avocado, banana, and carob trees in Guayas (Ecuador)

Abstract

The energy use of biomass in rural areas is starting to interest the farmers in Ecuador. Its use is recognized as environmentally friendly, but knowledge about the raw materials to be used as bioenergy remains meager. The objective of this research was to characterize five species located in the province of Guayas: avocado (Persea americana L.), carob (Prosopis spp.), mango (Mangifera indica L.), neem (Azadirachta indica L.), and bananas (Musa acuminata L.). The elemental composition and higher heating value were analyzed following harmonized standards. These species did not significantly differ in CHN composition, being about 33.012% C, 6.232% H, 0.610% N, and their higher heating value 14.322MJ kg-1. However, significant differences were found with respect to Cl and S: banana wood had the highest Cl and S content 1.162% and 0.134%, respectively, while avocado had the lowest Cl and S content, 0.032% and 0.063%, respectively. Fifteen mathematical models were formulated to predict the higher heating values from elemental analysis. Three of these were selected to be used under better conditions based primarily on C with an R2 greater than 0.829 and mean percentage absolute error less than 3.38%.