The capacity of double-effect evaporator is less than half of the capacity of two single effects, each of which is operating over same terminal temperature difference, when the________________ ?

Related Mcqs:

1. For the same heat transfer area and the terminal conditions, the ratio of the capacities of a single effect evaporator to a triple effect evaporator is_________________?

   A. 3
   B. 0.33
   C. 1
   D. 1.33

2. 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

3. Steam consumption in kg/hr in case of an evaporator is given by (where, C & E are capacity the economy of the evaporator respectively) ?

   A. C/E
   B. E/C
   C. CE
   D. 1/CE

4. In a single evaporator system, the steam economy ________________ by creating vacuum in the evaporator?

   A. Increases
   B. Decreases
   C. Remain constant
   D. May increase or decrease, depends on the vacuum

5. A dilute aqueous solution is to be concentrated in an evaporator system. High pressure steam is available. Multiple effect evaporator system is employed, because__________________?

   A. Total heat transfer area of all the effects is -less than that in a single effect evaporator system
   B. Total amount of vapor produced per Kg of feed steam in a multiple effect system is much
   higher than in a single effect
   C. Boiling point elevation in a single effect system is much higher than that in any effect in a
   multi-effect system
   D. Heat transfer co-efficient in a single effect is much lower than that in any effect in a multieffect
   system

6. 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

7. Reason for operating an evaporator in multiple effects is to secure ___________________?

   A. Increased steam economy
   B. Decreased steam consumption
   C. Both A. and B.
   D. Increased capacity

8. A multiple effect evaporator has a capacity to process 4000 kg of solid caustic soda per day, when it is concentrating from 10% to 25% solids. The water evaporated in kg per day is__________________?

   A. 6000
   B. 24000
   C. 60000
   D. 48000

9. In a single effect evaporator, the economy is________________?

   A. 1
   B. < 1
   C. > 1
   D. None of these

10. What is the steam economy in case of a single effect evaporator system ?

    A. 1
    B. > 1
    C. < 1
    D. 0.1