Question

In the commercial production of sugar, the product crystals are washed and centrifuged to partial dryness. The crystals are then sent through a rotary dryer where they are contacted with a hot stream of air that reduces the moisture content from 1.0 wt% to 0.1 wt%. The ratio of wet sugar to inlet air fed to the dryer is 3.3 kg wet sugar/kg inlet air. The inlet air contains 1.5 mole% water.

a.) Draw and label the flowchart and do the degree-of-freedom analysis.

b.) Taking a basis of 100 kg of wet sugar fed to the dryer, calculate the mass of water and its mole fraction in the air leaving the dryer.

c.) If 1000 tons/day of dried sugar is to be produced, at what rate (lbm/hr) is water evaporated from the sugar?

Answer 1