A. Steam pressure
B. Feed temperature
C. Number of effect
D. Both B. & C.
Related Mcqs:
- 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 - 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 - Economy of a multiple effect evaporator is not influenced much by the_______________________?
A. Boiling point elevations
B. Temperature of the feed
C. Rate of heat transfer
D. Ratio of the weight of the thin liquor to thick liquor - 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 - 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 - 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 - 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 - 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 - Economy of a multiple effect evaporator depends upon the _____________________?
A. Heat balance consideration
B. Rate of heat transfer
C. Both A. and B.
D. Neither A. nor B. - In a single effect evaporator, the economy is________________?
A. 1
B. < 1
C. > 1
D. None of these
