A. High vacuum in the evaporator
B. High evaporation rate
C. Foaming of the solution
D. High heat transfer rate
Related Mcqs:
- 1000 Kg of liquid at 30°C in a well stirred vessel has to be heated to 120°C, using immersed coils carrying condensing steam at 150°C. The area of the steam coils is 1.2 m2 and the overall heat transfer co-efficient to the liquid is 1500 W/m2.°C. Assuming negligible heat loss to the surrounding and specific heat capacity of the liquid to be 4 kJ/kg.°C, the time taken for the liquid to reach desired temperature will be__________________?
A. 15 min
B. 22 min
C. 44 min
D. 51 min - The separation of liquid droplets from the vapor is done by a/an _____________ in the evaporators?
A. Steam ejector
B. Entrainment separator
C. Compressor
D. Vacuum pump - The type of liquor circulation system to be ‘ employed in evaporators (viz. natural or forced circulation) is determined mainly by the ______________ of the liquid?
A. Viscosity
B. Density
C. Thermal conductivity
D. Corrosive nature - Open pan evaporators are preferred to be used, when the solution to be concentrated is_________________?
A. Scaling
B. Highly viscous
C. Corrosive
D. Salty - LMTD for evaporators & condensers for a given terminal parameters & set of conditions for counter-flow is equal to that for parallel flow. In such heat exchangers, with one of the fluids condensing or evaporating, the surface area required is the least in the ______________ flow?
A. Parallel
B. Mixed
C. Counter flow
D. Same in either A , B. or C. - Multiple effect evaporators are commonly used in the manufacture of P. Paper Q. Superphosphate R. Sugar S. Fats ?
A. P and Q
B. P and R
C. P and S
D. R and S - Viscous & heat sensitive liquids are concentrated in _____________ evaporators?
A. Open pan
B. Long tube
C. Agitated film
D. None of these - Multiple effect evaporators ar used to___________________?
A. Increase the steam economy & decrease the capacity
B. Increase the steam economy & the capacity
C. Decrease the steam economy & the capacity
D. Decrease the steam economy & increase the capacity - In evaporators, lowering the feed temperature_______________?
A. Increases the heating area required
B. Reduces the economy
C. Both A. and B.
D. Decreases the heating area required - The advantage of backward feed multiple effect evaporators over forward feed units is that___________________?
A. Heat sensitive material can be handled
B. There is no additional cost of pumping
C. Most concentrated liquid is at highest temperature
D. Equal heat transfer co-efficients exist in various effects
