A. High maintenance cost
B. Non-uniform & low production rate
C. High labour cost & low heat economy
D. All ‘a’, ‘b’ & ‘c’
Related Mcqs:
- Flooding in a vapor-liquid contacting equipment occurs in a tray, when the pressure drop through a tray is _______________ the liquid head available in the downcomer?
A. Less than
B. More than
C. Same as
D. Very much less - Rotary dryers cannot handle _______________ materials ?
A. Free flowing
B. Dry
C. Sticky
D. Granular - To get high tray efficiency___________________?
A. Interfacial surface between liquid and gas phase should be large
B. Time of contact between the two phases should be less
C. Gas velocity should be very low
D. Liquid entrainment should be severe - To get high tray efficiency___________________?
A. Interfacial surface between liquid and gas phase should be large
B. Time of contact between the two phases should be less
C. Gas velocity should be very low
D. Liquid entrainment should be severe - An aqueous solution of methanol is to be distilled in a tray column. High pressure steam is available as a source of heat. For a given reflux ratio and overhead composition, two options are being explored; (i) a reboiler is used and (ii) no reboiler is used but steam is fed directly to the bottom of the column. As compared to option (i), in option (ii) ____________________?
A. Less number of trays are required
B. Composition of the residue remains unchanged
C. More number of trays are required but the residue composition remains unchanged
D. More number of trays are required and the residue composition is more dilute in methanol - In distillation columns, the number of bubble caps per tray primarily depends upon the_______________________?
A. Allowable liquid velocity
B. Allowable gas velocity
C. Allowable gas and liquid velocities
D. Feed composition - Tray spacing in a distillation column of dia 10-12 ft. used in petroleum refinery may be around _____________ inches?
A. 5
B. 30
C. 60
D. 100 - Which of the following is not a batch drier ?
A. Truck drier
B. Agitated pan drier
C. Fluidised bed drier
D. Vacuum shelf drier - In the constant rate period of the rate of drying curve for batch drying,_________________?
A. Cracks develop on the surface of the solid
B. Rate of drying decreases abruptly
C. Surface evaporation of unbound moisture occurs
D. None of these - Advantage of continuous drying over batch drying is that the_____________________?
A. Drying cost per unit weight of dried product is less
B. Product with more uniform moisture content is produced
C. Equipment size required is smaller
D. All A , B. & C.
