A. Practical limit reached, due to low heat transfer rate because of inadequate temperature
difference
B. Economic limit reached, when the plant cost exceeds the saving of steam
C. Both A. & B.
D. Neither A. nor B.
Related Mcqs:
- Steam economy is defined as the amount of evaporation per unit amount of steam used, while the capacity is the total evaporation obtained per hour. Use of multiple effects in evaporation ?
A. Increases capacity
B. Increases economy
C. Does not affect the capacity
D. Both B. & C. - In a multiple effect evaporator system having ‘n’ effects, the amount of water evaporated per unit surface area in approximately equal to _____________ times that in a single effect?
A. nth
B. (1/n)th
C. 0.5 nth
D. 1.5 nth - Low pressure steam (with saturation temperature between 105 to 120°C) is usually used in the vacuum evaporators, which normally employ a vacuum of about _______________ mm Hg (referred to a 760 mm mercury barometer)?
A. 250
B. 450
C. 650
D. 750 - In which of the following evaporators, steam is fed inside the tube while the liquor is outside the tube ?
A. Long tube vertical evaporator
B. Short tube vertical evaporator
C. Horizontal tube evaporator
D. None of these - Optimum reflux ratio in a continuous distillation column is determined by the__________________?
A. Maximum permissible vapour velocity
B. Flooding limit of the column
C. Total cost consideration (fixed cost of the column plus the cooling water & steam cost)
D. None of these - The value of fouling factor depends upon the__________________?
A. Characteristic of process fluid
B. Velocity of process fluid containing suspended solids
C. Suspended solids in the fluid
D. All A., B. and C. - A head comprises of straight flange section, corner torus, section and central dished section. Crown radius and knuckle radius in a head is related respectively to the__________________?
A. Central dished section and corner torus section
B. Corner torus section and central dished section
C. Central dished section and straight flange section
D. Straight flange section and corner torus section - In a pressure vessel containing multiple openings of various dimensions at different parts, stress concentration at the edges of the opening is maximum which becomes negligibly small beyond the area covered by ______________ times the hole diameter?
A. Two
B. Five
C. Ten
D. Twenty - Multiple blade paddle agitator is used for mixing high viscosity liquids/paste in which the paddle diameter is commonly 0.8 times the tank diameter. However, the width of the blade is in the range of ______________ times the paddle diameter?
A. 0.1 to 0.25
B. 0.3 to 0.5
C. 0.5 to 0.6
D. 0.65 to 0.80 - The minimum shell thickness for tank ≤ 15 metres diameter is limited to _______________ mm, for reasons of elastic stability?
A. 2
B. 5
C. 10
D. 15
