To calculate the speed of the rotation of the drier;
Assume the peripheral speed of rotation to be 30feet/min
Revolution per min = peripheral speed / diameter
RPM = 30/8.07 = 3.7
The revolution of the drier varies between 2 and 5. Therefore the above value can be accepted
Flight design:
Number of flights in the drier = 3 x D
Where D is the diameter of the drier in feet
Number of flights = 3 x 8.07 = 24.21, say 24
Radial height of the flight:
The radial height of the flight taken as 1/8th of the diameter of the drier
The radial height of the flight = (1/8) x 8.07 = 12.18 inches, say 12.25”
DRIER DETAILS:
Drier Type: Counter Current Rotary Drier
Diameter of the drier = 8.07 ft = 2.46 m
Length of the Drier = 73.3 ft = 2.34 m
RPM of the drier = 3.7 rpm
Number of Flights = 24
Radial height of the flights = 12.25 inches
Temperature of the inlet air = 156°C = 313°F
Temperature of the inlet wet solid = 90°C = 194°F
Mean temperature Difference = 60°F
Air mass flow rate = 51000 lb/hr
Moisture removed by the drier = 1226 lb/hr
The volumetric heat transfer coefficient of drier = 5.57 Btu/Hr ft3°F