Forced circulation evaporators are useful for the concentration of viscous, salting and scale forming liquors. Which of the following is a forced circulation evaporator ?

Related Mcqs:

1. 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

2. Forced circulation evaporators are normally used for concentrating liquids having ___________________?

   A. Scaling characteristics
   B. High viscosity
   C. Both A. & B.
   D. Neither A. nor B.

3. Which is the most suitable for the concentration of foamy & frothy liquors ?

   A. Agitated film evaporator
   B. Long tube vertical evaporator
   C. Open pan evaporator
   D. None of these

4. Viscous & heat sensitive liquids are concentrated in _____________ evaporators?

   A. Open pan
   B. Long tube
   C. Agitated film
   D. None of these

5. Which of the following forced convection heat transfer equation accounts for the liquid viscosity effect for viscous liquids ?

   A. Dittus-Boelter equation
   B. Sieder-Tate equation
   C. Nusselt equation
   D. None of these

6. For evaporation of viscous solution in a multiple effect evaporator, the preferred feeding scheme is _________________?

   A. Forward
   B. Backward
   C. Parallel
   D. None of these

7. In forced circulation, the heating element is injected_________________?

   A. Internally
   B. Externally
   C. Both A. and A.
   D. Neither A. nor B.

8. Circulation pump is located below the evaporator to___________________?

   A. Avoid cavitation
   B. Avoid frequent priming
   C. Create more suction head
   D. None of these

9. A multiple effect evaporator as compared to a single effect evaporator of the same capacity has _________________?

   A. Lower heat transfer area
   B. Lower steam economy
   C. Higher steam economy
   D. Higher solute concentration in the product

10. 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/kg.K. 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