Drying kinetics of a porous spherical particle and the inversion temperature

A model is presented for drying of a single porous particle with superheated steam and humid air. Experimental data for spherical porous ceramic particle reported in the literature were used for the validation of the model. An inversion temperature at which the evaporation rates within superheated steam and humid air are equal was predicted. The effect of thermophysical properties of the particle (permeability 10(-14) - 10(-17) m(2), diameter 3 x 10(-3) -10 x 10(-3) m) and operating variables (gas mass flux 0.26 - 0.78 kg m(-2) s(-1), drying agent temperature 120-200 degrees C) is tested. The inversion temperature is shown to be affected by the thermophysical properties of the porous particle and of the drying agent.