Thin-layer Dehumidification Drying Studies on Rough Rice (Part 2)

Open Airflow System Including Dehumidifier

Abstract

Thin-layer drying of rough rice was conducted at different drying air temperature and relative humidity (r.h.) combinations to fundamentally elucidate the characteristics of an open airflow dehumidification drying system. Against changing ambient temperature and r.h., it was obviously difficult to condition open air introduced into a dehumidifier to arbitrarily set values, particularly to such low temperature as 10°C Patterns of moisture reduction with time were typical exponential curves. Drying curves showed two falling-rate periods. The overall drying rate increased as drying air temperature increased and r.h. decreased, but the effect of temperature increase was dominant. The relationships between drying rate and fissure occurrence were described by exponential curves. Total fissured grains were generally lower than the results obtained in the closed air recirculation system.