Abstract
This investigation focused on the optimization of pre-treatment conditions of pine waste. The genetic algorithm was applied to determine local Pareto sets of the objective functions of the ash content obtained after proximate analyses of torrefied samples of pine waste (needles), energy consumption during torrefaction, energy yield, fuel value index, severity factor, and energy-mass co-benefit index. The milled form of pine waste samples underwent torrefaction for 5 min, 10 min, and 15 min at temperatures of 210 °C, 220 °C, 230 °C, 240 °C, and 250 °C. The energy dispersive spectroscopy of pine waste after pretreatment was also considered to evaluate the impact of processing parameters on the elemental composition of organic/inorganic content presented in pine waste. The torrefaction condition to minimize the ash content and maximize the volumetric energy density would occur at 249.98 °C for a residence period of 5 min. The torrefaction of pine waste must be performed at 217.24 °C for 15 min to minimize the electricity consumption of an improvised unit. The energy yield obtained experimentally at 250 °C for 5 min showed a consensus with the corresponding solution obtained through the genetic programming. The Pareto front developed for the selected parameters provided a good consensus with the empirical results. The percentage of Ca and Fe contents dropped by 84% and 50% in thermally processed pine waste, respectively.
