An accurate drying model is useful in assisting process design and product design when drying is involved. Generally, drying models can be classified into equilibrium and non-equilibrium multiphase models. Both models employ a similar set of equations of conservation of heat and mass transfer. For the equilibrium ones, the moisture sorption isotherm relationship is used to link the concentration of water vapor inside the pore space and moisture content in and on solid matrix. On the other hand, the non-equilibrium ones have an expression of local evaporation/condensation rate to relate these relationships. Here, both models are compared and assessed to model several cases of convective and intermittent drying. The reaction engineering approach (REA) is used to describe the local evaporation/condensation rate in non-equlibrium model (i.e. the spatial reaction engineering approach (S-REA)). The results of modeling indicate that for the cases investigated, the equilibrium model does not work well. The S-REA can accurately model both convective and intermittent drying cases. For the interest of probing the dynamics of drying process, it is suggested that a non-equilibrium model is more appropriate.
- Spatial reaction engineering approach (S-REA)
ASJC Scopus subject areas
- Chemical Engineering(all)