Tutorial 4 : Drying

4.1 ) Insoluble wet granular materials are placed in a container with a diameter of 0.574 metres and a depth of 1.8 metres, and the container is dried in an air pressure drier. Convectional heat transfer from a surface-parallel air stream. scalding air delivers adequate heat to dry the wet product from 0.20 kg water per kilogramme dry solid to 0.02 kg water per kg dry solid, which is the critical moisture level. The hot air is supplied at a continuous flow rate of 3.03 m s^-1 at a temperature of 76.3 oC with a humidity of 0.04 kg water per kg dry air. The container has insulated sides and a bottom, and the dry material has a density of 97 kg m^-3. This empirical equation can be used to express the convective heat transfer coefficient for the parallel flow - h = 0.0204G^0.8

Convective heat transfer coefficient is measured in kW m^-2 K^-1, while air mass velocity is measured in G. (i) Calculate the air mass velocity, the constant drying rate, and the drying time for the material.

ii) List three industries where the drying process is extensively used.

iii) In this situation, what influences drying rate