Generalized drying rate curves in conductive/convective paper drying

Abstract

The drying of paper (cellulose) sheets over heated surfaces, under natural and forced air conditions is studied. Samples were placed over the upper surface of a metallic box heated by a thermostatic bath. The system is exposed to ambient air under two different conditions: natural convection and forced convection provided by an adjustable blower. Samples consisted of pure eucalyptus pressed cellulose (about 1 mm thick). Moisture content of sheets (dry basis, d.b.) was determined from their constant weight in an oven at a temperature of 105ºC. The influence of initial paper moisture content, drying (heated surface) temperature and air velocity on the drying rate curves behavior was analyzed under different drying conditions and studied through generalized drying rate curves. A model was then successfully employed to fit them.