Development and validation of torrefaction optimization model applied element content prediction of biomass

In terms of heat energy, woody biomass is not as effective as fossil fuels owing to its hydrophilic characteristics and low calorific value. These disadvantages can be overcome through torrefaction, a low-temperature pyrolysis method that can increase the energy density of woody biomass by increasing its carbon content ratio. However, it is difficult to increase the calorific value within a short processing time, while long processing times decrease the useful heating value. Therefore, optimal conditions need to be determined. Accordingly, this study attempted to optimize the torrefaction of woody biomass using a one-dimensional simulation analysis. Changes in the elemental contents of biomass were predicted by analyzing the mass reduction and characteristics of volatile matter emission due to torrefaction, and changes in the calorific value were derived. Comparing experiments and simulations. We estimated the calorific value and optimal conditions according to the process temperature and time (200 °C at 40 min, 230 °C at 30 min, 250 °C at 20 min). This study provides preliminary findings for the effective utilization of biomass, a material that is usually discarded.