CALCULATIONS :

Consider a rotary dryer for which temperature course is similar to figure 2

 

 

C_S = Specific heat of material kcal/kg dry solid

t_G = Temperature of air stream

t = Temperature of solid

A = Cross sectional area of dryer

Z = Distance along dryer

L = Length of the dryer =1.5 m

U = Overall heat transfer co-effecient , kcal/(h-⁰C-m² of solid surface)

 

 

FIGURE 2

For determining U_a use the equation (perry)

D = Dryer diameter (in feet)

For economic operation of a rotary dryer

Flow sheet describing the steps of calculations in details :