A high vapour velocity is required for high plate efficiency in a seive plate coloumn. The satisfactory value of operating vapor velocity for design purpose in seive plate column is about __________ percent of the flooding velocity.
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A pipe is generally made of circular cross-section, because a circular cross-section has the
A. Higher structural strength
B. Lowest surface area requirement for a given volume
C. Both A & B
D. None of these
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For a cylindrical shell, (subject to the thickness of uppermost course being more than the minimum for diaofthe tank in question), the thickness of the courses of shell
A. Decreases upwards
B. Increases upwards
C. Remains same throughout
D. May decrease or increase upwards depending upon whether vacuum or positive pressure would be maintained inside the shell
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Angled baffles are preferred in the agitation tank to control the swirling action; if the viscosity of the liquid to be mixed is about 200 poise. However, the baffle may be completely eliminated for mixing liquids having viscoisty above __________ poise.
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What is the slope of the feed line, if the feed to a distillation column is a saturated liquid?
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With increase in pressure drop (for a given particle size), the dust collection efficiency of a cyclone separator will
A. Increase
B. Decrease
C. Remain unaffected
D. Increase or decrease depending on the nature of the dust
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LMTD correction factor is used in heat exchanger design for
A. Double pipe heat exchanger
B. Multipass shell and tube heat exchanger
C. Fouling fluids
D. Counter flow of hot and cold fluids
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Diameter of bubble caps used in high pressure columns is __________ as compared to that used in identical vacuum columns.
A. Less
B. More
C. Same
D. Either A or B; no generalisation can be made
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Pick out the wrong statement
A. In a flanged and standard dished head, the crown radius is ≤ shell outside diameter
B. In a flanged and shallow dished head, the crown radius is > shell outside diameter
C. Flat head covers are most suitable for larger vessels operating at very high pressure
D. Flanged only head is a type of flat head in which gradual change in the shape at the centre results in reduced local stresses
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At the following point for a given packing and set of fluids, the pressure drop per metre of packed height, with variation in fluid rates and operating pressure
A. Increases
B. Decreases
C. Remains same
D. May increase or decrease depending upon the solubility of the gas in the liquid
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The thickness of heat transfer plates used in the plate type heat exchanger ranges from __________ mm, pressed in a single piece provided with grooves & corrugations.
A. 0.3 to 0.8
B. 1.25 to 3.125
C. 3.5 to 7.0
D. 8-12
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The type of stress developed in a metallic bar on subjecting it to a change in temperature without allowing it to be deformed is __________ stress.
A. Shear
B. Tensile
C. Compressive
D. Thermal
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Normal screwed fittings are used for pipes upto a diameter of __________ inches.
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Reflux ratio variation in a distillation column is between
A. Zero and infinity
B. Zero and one
C. Minimum and infinity
D. None of these
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In a bag filter, the pressure drop increases directly as the
A. Density of the gas, but is independent of the viscosity of the gas
B. Density of the gas and inversely as viscosity of the gas
C. Viscosity of the gas and inversely as density of the gas
D. None of these
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Which of the following is the best tube material from thermal conductivity point of view alone?
A. Aluminium
B. Stainless steel
C. Copper
D. Carbon steel
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In a heat exchanger, shell side fluid velocity can be changed by changing the tube
A. Layout
B. Pitch
C. Both A & B
D. Neither A nor B
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Bubble cap tray is the most commonly used tray in large distillation column, because
A. Of its flexibility and nearly constant efficiency under varying conditions of operation
B. It incurs less pressure drop as compared to any other try designed for the same duty
C. It eliminates the foaming and entrain-ment tendency during operation
D. None of these
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The slope of the feed line in distillation opeartion is given by (where, q = fraction of the feed stream that is liquid.)
A. − q
B. − 1 − q q
C. − q − 1 q
D. None of these
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What is the value of 'q' for saturated vapor feed to a distillation column ?
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