Energy viability of industrial drying of wood chips

Abstract

Moisture content (MC) is one of the physical properties of wood that most influences its energy efficiency as fuel. The aim of the present study was to analyze the viability of drying pine wood chips in comparison to undried chips, considering the balance of the energy content as the primary evaluation parameter. We also investigated whether the increase in the energy content of dried wood chips exceeds the energy required for the drying process, demonstrating energy viability. The base scenario was created using data from an industry that performs wood chip drying in a rotary dryer that reduces the MC by 15%. Based on the baseline scenario data, two new scenarios were estimated to represent variations in energy consumption to reproduce the same drying process, taking into account different combinations of MC in the input and output chips. The results showed that drying increased the energy content of wood chips by 44.96% (from 7,194 MJ.kg−1 to 10,429 MJ.kg−1). However, the energy balance of the drying process was negative in all scenarios evaluated, demonstrating that the energy expenditure required to dry wood chips exceeded the increase in energy content resulting from the reduction in MC under the conditions evaluated.