The average velocity in the tubes of a 1-4 heat exchanger is __________ times that in 1-1 heat exchanger having the same size & number of tubes and operated at same liquid flow rate.
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Baffles are provided in a shell and tube heat exchanger to increase the turbulence and velocity of the shell side fluid. Which of the following shaped baffles does not fall in the category of transverse baffle?
A. Segmental baffle
B. Flat plate extending across the wall
C. Disk type baffle
D. Helical type baffle
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Smoker's equation for the calculation of number of equilibrium stages in a continuous binary distillation column is used, when the
A. Relative volatility is close to one (e.g., separation of close boiling isomers)
B. Feed is not at its bubble point
C. Number of equilibrium stages in only stripping section is to be calculated
D. Number of equilibrium stages required is likely to be very small
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Number of evaporators which can be used in service in a multiple effect evaporation system is limited by the
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
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Pick out the wrong statement
A. For all the cylindrical process vessels operating above atmospheric pressure, formed heads are used for closing the vessel
B. Fouling factor of river water is less than that of sea water
C. Risers provided in bubble cap trays in the distillation column facilitate the flow of both liquid and vapor
D. Both B and C
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Equivalent diameter for heat transfer calculation for a duct of square cross-section having each side as 'd' will be
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Lap joints are preferred for plates having thickness __________ mm.
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Diameter of the seive tray column is determined by the
A. Lower limit of vapour velocity
B. Upper limit of the vapour velocity
C. Hole diameter of the seive tray
D. Height of the plate spacing
Select an option to see the answer and solution.
Baffles may be eliminated for
A. Low viscosity liquids (< 200 poise)
B. High viscosity liquids (> 600 poise)
C. Large diameter tanks
D. None of these
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__________ is the determining factor for the number of bubble caps to be used per tray.
A. Permissible slot velocity
B. Tray diameter
C. Liquid load
D. Vapor load
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If a single tube pass heat exchanger is converted to two passes; for the same flow rate, the pressure drop per unit length in tube side will __________ times.
A. Increase by 1.8
B. Decrease by 22
C. Increase by 21.6
D. None of these
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For a given design of bubble cap, the number of bubble caps to be used per tray is set by the
A. Allowable gas velocity through the slots
B. Plate spacing
C. Diameter of the column
D. All of the above
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Where does the maximum tensile strength occur in a thick cylindrical vessel subjected to internal pressure?
A. At the inner surface
B. At the mid thickness of the cylindrical wall
C. At the outer surface
D. None of these
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Steam side heat transfer co-efficient for design consideration under ordinary condition can be assumed to be about __________ kcal/hr.m2 .°C.
A. 1250
B. 2500
C. 7500
D. 15000
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D L e
A. Less than that for Tee (used as elbow, entering run)
B. More than that for Tee (used as elbow, entering run)
C. Around 90
D. Both B and C
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Bubble cap plate column is
A. A finite stage contactor
B. Used only for distillation, not for absorption
C. A differential stage contactor
D. A continuous contactor
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In a distillation column, minimum clearance to be maintained betweeen the overflow weir and the last row of the bubble caps is __________ cms.
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The thermal stress in a metallic bar does not depend upon the
A. Changes in temperature
B. Cross-sectional area
C. Both A & B
D. Neither A nor B
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Maximum allowable vapour velocity in a bubble cap tower is determined by the
A. Entrainment considerations
B. Vapour density
C. Diameter of the column
D. None of these
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In actual operation of distillation column, the vapour is not distributed uniformly among the bubble caps, primarily because of the
A. Liquid gradient on the tray
B. Lower skirt clearance
C. Lower static submergence
D. Small downcomer liquid seal
Select an option to see the answer and solution.
