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

Related Mcqs:

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 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
A process stream of dilute aqueous solution flowing at the rate of10 Kg.s-1 is to be heated. Steam condensate at 95°C is available for heating purpose, also at a rate of 10 Kg.s-1. A 1 – 1 shell and tube heat exchanger is available. The best arrangement is_______________?
A. Counter flow with process stream on shell side
B. Counter flow with process stream on tube side
C. Parallel flow with process stream on shell side
D. Parallel flow with process stream on tube side
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
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
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
Evaporation of 1kg of water from a solution in a single effect evaporator requires about ________________ kg of steam?
A. 0.4 – 0.6
B. 1-1.3
C. 1.8-2
D. 2 – 2.4
In a multiple effect evaporator, the effect of boiling point elevation is to______________________?
A. Reduce the capacity
B. Reduce the economy
C. Increase the economy
D. None of these
Boiling point elevation for a strong and concentrated solution is found by Duhring’s rule, which states that at the same pressure, the boiling point of a solution is a linear function of the _______________ of pure water?
A. Boiling point
B. Dynamic viscosity
C. Kinematic viscosity
D. Density
An evaporator while concentrating an aqueous solution from 10 to 40% solids evaporates 30000 kg of water. The amount of solids handled by the system in kg is___________________?
A. 4000
B. 9000
C. 4600
D. 3000