Equilibrium moisture content in charcoal exposed to different relative humidity conditions

Abstract

Equilibrium moisture content is an important characteristic associated with hydrocarbon fuels, including biomass and charcoal. Its determination is essential since it negatively affects several properties, especially the caloric value and energy density. Thus, this research was conducted with the aim of determining the equilibrium moisture content of charcoal produced for industrial purposes from 6-year-old Eucalyptus and Corymbia species exposed to different relative humidity conditions at a temperature of 30°C. Four samples of charcoal were collected from each of the four species of Eucalyptus and Corymbia used in the study. The equilibrium moisture content of the samples was always achieved by desorption. At the end of the experiment, the dry masses were obtained. Twelve simple and multiple linear models were used to estimate the equilibrium moisture of the samples. Overall average equilibrium moisture estimates were slightly higher in Eucalyptus species in all relative humidity conditions, except at 90%. Considering the scientific principle of parsimony, the simple linear model was selected for both Corymbia and Eucalyptus species. The difference between Corymbia and Eucalyptus equilibrium moisture of charcoal was higher at lower relative humidity conditions.