It is desired to concentrate a 20% salt solution (20 kg of salt in 100 kg of solution) to a 30% salt solution in an evaporator. Consider a feed of 300 kg/min at 30°C. The boiling point of the solution is 110°C, the latent heat of vaporisation is 2100 kJ/kg and the specific heat of the solution is 4 kJ/(kgK). The rate at which the heat has to be supplied in (kJ/min) to the evaporator is
A. 3.06 × 105
B. 6.12 × 105
C. 7.24 × 105
D. 9.08 × 105
Answer: Option A
This Question Belongs to Chemical Engineering >> Heat Transfer
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Related Questions on Heat Transfer
A. 3.06 × 105
B. 6.12 × 105
C. 7.24 × 105
D. 9.08 × 105
Fqra cold viscous feed, backward feed gives __________ than forward feed.
A. A higher capacity
B. A lower capacity
C. Lower economy
D. None of these
A. Twice
B. Four times
C. Square root of
D. Square of
Solute Balance
0.2 * 300 = 0.3 * m'
m' = 200 kg /min
water evaporated
mv = 300 - 200 = 100 kg/min
Heat Balance across evaporator
Q = m*Cp*(Tb - Ti) + (latent heat *mv)
= 300*4*(110 - 30) + (2100 * 100)
= 3.05 * 10^5 kJ/min
Option (A)