Some considerations in simulation of superheated steam drying of softwood lumber

A mathematical model for high-temperature drying of softwood lumber with moist air has been modified and extended to simulate wood drying with superheated steam. In the simulation, differences between the two types of drying are considered, these include: external heat and mass transfer processes and calculation of equilibrium moisture content. The external mass transfer coefficient in the superheated steam drying was found to be,much higher than that in the moist air drying, however, the heat transfer coefficients for these two cases were of the same order. The predicted drying curves and wood temperatures from the superheated steam drying model Were compared with experimental data and there was close agreement. Further studies will apply the model to development of commercial drying schedules for wood drying with superheated steam.