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

Related Mcqs:

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

   A. Long vertical evaporator
   B. Horizontal tube evaporator
   C. Agitated film evaporator
   D. Calandria vertical tube evaporator

2. Agitated film evaporator is suitable for concentrating _____________ liquids?

   A. Foaming
   B. Viscous
   C. Very thin
   D. Corrosive

3. For concentrating an aqueous solution of a material like anhydrous Na2SO4, whose solubility decreases with rise in temperature, the most suitable evaporator is a _______________ evaporator?

   A. High pressure
   B. Vacuum
   C. Backward feed
   D. None of these

4. Which is the most suitable for the concert-ration of highly concentrated solution ?

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

5. _____________ heat exchanger is the most suitable, when the temperature of shell side fluid is much higher than that of tube side?

   A. Single pass, fixed tube sheet
   B. U-tube
   C. Three pass, fixed tube sheet
   D. None of these

6. For gases, the thermal conductivity increases with temperature rise. For liquids, with increase in concentration, its thermal conductivity generally ?

   A. Decreases
   B. Increases
   C. Remains unchanged
   D. Increases exponentially

7. Grashoff number is given by________________?

   A. gD3.β.Δtρ2/μ2
   B. gD2βΔtρ/μ2
   C. gD2βΔtP2μ
   D. gD3βΔtP2/μ

8. Which of the following is directly concerned with the heat transfer ?

   A. Strouhal number
   B. Sherwood number
   C. Euler number
   D. Grashoff number

9. The actual temperature drop across the heating surface of an evaporator depends on the_______________?

   A. Liquid depth over the heating surface
   B. Solution being evaporated
   C. Pressure difference between the steam chest and the vapor space above the boiling liquid
   D. All A., B. and C.

10. In case of _______________ boiling, the liquid temperature is below the saturation temperature and the boiling takes place in the vicinity of the heated surface?

    A. Nucleate
    B. Local
    C. Pool
    D. Saturated