Weeping in a distillation column (A) Increases tray efficiency (B) Provides large interfacial surface for mass transfer (C) Results due to very high gas velocity (D) Results due to very low gas velocity

Weeping in a distillation column

(A) Increases tray efficiency

(B) Provides large interfacial surface for mass transfer

(C) Results due to very high gas velocity

(D) Results due to very low gas velocity

by

1 Answer

Answer :

(D) Results due to very low gas velocity

by

Related questions

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

Description : 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

Last Answer : (A) Interfacial surface between liquid and gas phase should be large

Pick out the wrong statement. (A) Mechanical agitation is required, if the system has low interfacial tension (B) Sieve tray towers are generally used for systems having low interfacial tension (C) When Henry's law constant is very small, then the mass transfer rate is controlled by the gas film resistance (D) Taylor-Prandtl analogy for heat and mass transfer considers the transfer through both laminar and turbulent layers

Description : Pick out the wrong statement. (A) Mechanical agitation is required, if the system has low interfacial tension (B) Sieve tray towers are generally used for systems having low ... Prandtl analogy for heat and mass transfer considers the transfer through both laminar and turbulent layers

Last Answer : (A) Mechanical agitation is required, if the system has low interfacial tension

Back-trapping in a distillation column (A) Increases tray efficiency (B) Decreases tray efficiency (C) Reduces pressure drop (D) Is desirable, as it provides improved vapour-liquid contact

Description : Back-trapping in a distillation column (A) Increases tray efficiency (B) Decreases tray efficiency (C) Reduces pressure drop (D) Is desirable, as it provides improved vapour-liquid contact

Last Answer : (B) Decreases tray efficiency

Priming in a distillation column (A) Results from very low gas velocity (B) Is desirable from point efficiency consideration (C) Is characterised by the presence of foam throughout the space between trays (D) Reduces the overall pressure drop

Description : Priming in a distillation column (A) Results from very low gas velocity (B) Is desirable from point efficiency consideration (C) Is characterised by the presence of foam throughout the space between trays (D) Reduces the overall pressure drop

Last Answer : (C) Is characterised by the presence of foam throughout the space between trays

Plate efficiency in a distillation column is reduced due to the __________ of liquid. (A) Entrainment (B) Foaming (C) Weeping & dumping (D) All (A), (B) & (C)

Description : Plate efficiency in a distillation column is reduced due to the __________ of liquid. (A) Entrainment (B) Foaming (C) Weeping & dumping (D) All (A), (B) & (C)

Last Answer : (D) All (A), (B) & (C)

Flooding results in (A) High tray efficiency (B) Low tray efficiency (C) High gas velocity (D) Good contact between the fluids

Description : Flooding results in (A) High tray efficiency (B) Low tray efficiency (C) High gas velocity (D) Good contact between the fluids

Last Answer : (B) Low tray efficiency

Plate efficiency (A) Is a function of the mass transfer between liquid and vapour (B) Increases due to foaming (C) Increases due to liquid entrainment (D) Increases due to weeping and dumping of liquid

Description : Plate efficiency (A) Is a function of the mass transfer between liquid and vapour (B) Increases due to foaming (C) Increases due to liquid entrainment (D) Increases due to weeping and dumping of liquid

Last Answer : (A) Is a function of the mass transfer between liquid and vapour

Measurement of the interfacial area of mass transfer is achieved easily & accurately in case of a __________ column. (A) Spray (B) Packed (C) Bubble cap plate (D) Wetted wall

Description : Measurement of the interfacial area of mass transfer is achieved easily & accurately in case of a __________ column. (A) Spray (B) Packed (C) Bubble cap plate (D) Wetted wall

Last Answer : (D) Wetted wall

Entrainer used in Azeotropic distillation should (A) Form a low boiling azeotrope with one of the constituents of the mixture (B) Form a new azeotrope of low relative volatility with one of the constituents of the mixture (C) Have high latent heat of vaporisation (D) Have high viscosity to provide high tray efficiency

Description : Entrainer used in Azeotropic distillation should (A) Form a low boiling azeotrope with one of the constituents of the mixture (B) Form a new azeotrope of low relative volatility with one of the ... (C) Have high latent heat of vaporisation (D) Have high viscosity to provide high tray efficiency

Last Answer : (A) Form a low boiling azeotrope with one of the constituents of the mixture

Pick out the wrong statement. (A) In solvent extraction, the distribution co-efficient should be as large as possible for solvent economy (B) With increase in pressure, the solubility of gases in solvent increases at a fixed temperature (C) Decrease in Murphree plate efficiency is an indication of entrainment in distillation column (D) The capacity of a distillation column is maximum at total reflux

Description : Pick out the wrong statement. (A) In solvent extraction, the distribution co-efficient should be as large as possible for solvent economy (B) With increase in pressure, the solubility of ... in distillation column (D) The capacity of a distillation column is maximum at total reflux

Last Answer : (D) The capacity of a distillation column is maximum at total reflux

The rate of mass transfer is not dependent upon the (A) Degree of dispersion of one fluid in the other (B) Interfacial surface exposed between the phases (C) Both (A) & (B) (D) None of these

Description : The rate of mass transfer is not dependent upon the (A) Degree of dispersion of one fluid in the other (B) Interfacial surface exposed between the phases (C) Both (A) & (B) (D) None of these

Last Answer : (D) None of these

In extractive distillation, solvent is (A) Added to alter the relative volatility of the mixture (B) Of high volatility (C) Present in overhead stream (D) Of high viscosity to give high tray efficiency

Description : In extractive distillation, solvent is (A) Added to alter the relative volatility of the mixture (B) Of high volatility (C) Present in overhead stream (D) Of high viscosity to give high tray efficiency

Last Answer : (A) Added to alter the relative volatility of the mixture

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

Description : 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

Last Answer : (C) Allowable gas and liquid velocities

Pick out the wrong statement. (A) In the McCabe-Thiele diagram for binary distillation, vertical feed line represents saturated liquid feed and horizontal feed line represents saturated vapour feed (B) In small columns, local efficiency is larger than Murphree efficiency; in large columns local efficiency is smaller than Murphree efficiency (C) For Laminar flow over a plate of length L, the local mass transfer co￾efficient at a distance L from the leading edge is 1.5 × 10 -2m/s. Then the average mass transfer co-efficient for the plate is 2 × 10 -2m/s (D) The concentration and hydrodynamic boundary layers over a flat plate are of equal thickness, if Schmidt number is equal to unity

Description : Pick out the wrong statement. (A) In the McCabe-Thiele diagram for binary distillation, vertical feed line represents saturated liquid feed and horizontal feed line represents saturated vapour feed (B) In ... layers over a flat plate are of equal thickness, if Schmidt number is equal to unity

Last Answer : (C) For Laminar flow over a plate of length L, the local mass transfer co￾efficient at a distance L from the leading edge is 1.5 × 10 -2m/s. Then the average mass transfer co-efficient for the plate is 2 × 10 -2m/s

The individual mass transfer co-efficients (moles/m2s) for absorption of a solute from a gas mixture into a liquid solvent are, KL = 4.5 and KG = 1.5. The slope of the equilibrium line is 3. Which of the following resistance (s) is (are) controlling? (A) Liquid side (B) Gas side (C) Interfacial (D) Both liquid and gas side

Description : The individual mass transfer co-efficients (moles/m2s) for absorption of a solute from a gas mixture into a liquid solvent are, KL = 4.5 and KG = 1.5. The slope of the equilibrium line is 3. Which of ... A) Liquid side (B) Gas side (C) Interfacial (D) Both liquid and gas side

Last Answer : (B) Gas side

Small dia distillation column can be a (A) Packed column (B) Sieve tray (C) Bubble cap (D) Any of these

Description : Small dia distillation column can be a (A) Packed column (B) Sieve tray (C) Bubble cap (D) Any of these

Last Answer : (A) Packed column

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

Description : 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

Last Answer : (B) 30

Heat exchangers operating, when the asymptotic range is reached, (A) Provide very large heat transfer co-efficient (B) Results in making part of the heating surface inactive (C) Results in abruptly increased velocity (D) None of these

Description : Heat exchangers operating, when the asymptotic range is reached, (A) Provide very large heat transfer co-efficient (B) Results in making part of the heating surface inactive (C) Results in abruptly increased velocity (D) None of these

Last Answer : (B) Results in making part of the heating surface inactive

Pick out the correct statement. (A) The slope of the stripping line is always less than unity (B) For a given separation in a binary distillation column, with increase in reflux ratio (above the minimum reflux ratio), the fixed cost of the distillation column first increases and then decreases (C) In Ponchon-Savarit method of no. of theoretical plate determination, the stripping and rectifying operating lines are vertical at total reflux (D) Kremser-Brown-Souder's equation is used to calculate the efficiency of a plate tower

Description : Pick out the correct statement. (A) The slope of the stripping line is always less than unity (B) For a given separation in a binary distillation column, with increase in reflux ratio ( ... (D) Kremser-Brown-Souder's equation is used to calculate the efficiency of a plate tower

Last Answer : C) In Ponchon-Savarit method of no. of theoretical plate determination, the stripping and rectifying operating lines are vertical at total reflux

Flooding in a column results due to (A) High pressure drop (B) Low pressure drop (C) Low velocity of the liquid (D) High temperature

Description : Flooding in a column results due to (A) High pressure drop (B) Low pressure drop (C) Low velocity of the liquid (D) High temperature

Last Answer : (A) High pressure drop

Fractional solvent extraction (A) Employs only one solvent (B) Employs two solvents (C) Results in low interfacial tension (D) None of these

Description : Fractional solvent extraction (A) Employs only one solvent (B) Employs two solvents (C) Results in low interfacial tension (D) None of these

Last Answer : (B) Employs two solvents

Mass transfer rate between two fluid phases does not necessarily depend on the __________ of the two phases. (A) Chemical properties (B) Physical properties (C) Degree of turbulence (D) Interfacial area

Description : Mass transfer rate between two fluid phases does not necessarily depend on the __________ of the two phases. (A) Chemical properties (B) Physical properties (C) Degree of turbulence (D) Interfacial area

Last Answer : (A) Chemical properties

As the reflux ratio in a distillation column is increased from the minimum, the (A) Slope of the operating line in stripping section decreases (B) Number of plates decreases very slowly first and then more and more rapidly (C) Total cost first decreases and then increases (D) Liquid flow increases while the vapor flow decreases for a system

Description : As the reflux ratio in a distillation column is increased from the minimum, the (A) Slope of the operating line in stripping section decreases (B) Number of plates decreases very slowly first ... decreases and then increases (D) Liquid flow increases while the vapor flow decreases for a system

Last Answer : (C) Total cost first decreases and then increases

. __________ column is preferred to be used, when a high liquid hold up is required in a reactor for gas-liquid reaction. (A) Packed (B) Bubble (C) Spray (D) Tray

Description : . __________ column is preferred to be used, when a high liquid hold up is required in a reactor for gas-liquid reaction. (A) Packed (B) Bubble (C) Spray (D) Tray

Last Answer : (B) Bubble

When a high liquid hold up is required in a reactor for gas liquid reaction, use __________ column. (A) Packed (B) Spray (C) Tray (D) Bubble

Description : When a high liquid hold up is required in a reactor for gas liquid reaction, use __________ column. (A) Packed (B) Spray (C) Tray (D) Bubble

Last Answer : (D) Bubble

Overall efficiency of the distillation column is (A) The ratio of number of ideal plates to actual plates (B) The ratio of number of actual plates to ideal plates (C) Same as the Murphree efficiency (D) Always more than the point efficiency

Description : Overall efficiency of the distillation column is (A) The ratio of number of ideal plates to actual plates (B) The ratio of number of actual plates to ideal plates (C) Same as the Murphree efficiency (D) Always more than the point efficiency

Last Answer : (A) The ratio of number of ideal plates to actual plates

Flooding in a distillation column is detected by a sharp (A) Increase in Murphree plate efficiency (B) Decrease in pressure drop (C) Decrease in liquid hold up in the column (D) Increase in pressure drop

Description : Flooding in a distillation column is detected by a sharp (A) Increase in Murphree plate efficiency (B) Decrease in pressure drop (C) Decrease in liquid hold up in the column (D) Increase in pressure drop

Last Answer : (D) Increase in pressure drop

Minimum reflux ratio in a distillation column results in (A) Optimum number of trays (B) Minimum reboiler size (C) Maximum condenser size (D) Minimum number of trays

Description : Minimum reflux ratio in a distillation column results in (A) Optimum number of trays (B) Minimum reboiler size (C) Maximum condenser size (D) Minimum number of trays

Last Answer : (C) Maximum condenser size

__________ column is used in gas absorption process. (A) Wetted wall (B) Sieve/perforated tray (C) Bubble cap (D) Packed

Description : __________ column is used in gas absorption process. (A) Wetted wall (B) Sieve/perforated tray (C) Bubble cap (D) Packed

Last Answer : (D) Packed

Pick out the wrong statement. (A) Critical moisture content is not a property of the material itself (B) A sharp increase in pressure drop gives an indication of the flooding in a distillation column (C) Separation of components is not possible in liquid extraction, if selectivity is unity (D) Dehydration of ethyl alcohol is most economically done by molecular distillation at very high vacuum

Description : Pick out the wrong statement. (A) Critical moisture content is not a property of the material itself (B) A sharp increase in pressure drop gives an indication of the flooding in a ... unity (D) Dehydration of ethyl alcohol is most economically done by molecular distillation at very high vacuum

Last Answer : (D) Dehydration of ethyl alcohol is most economically done by molecular distillation at very high vacuum

Design calculation for multiple component distillation is done by (A) Ponchon-Savarit method (B) McCabe-Thiele method (C) Enthalpy concentration method (D) Tray to tray calculations

Description : Design calculation for multiple component distillation is done by (A) Ponchon-Savarit method (B) McCabe-Thiele method (C) Enthalpy concentration method (D) Tray to tray calculations

Last Answer : (D) Tray to tray calculations

Umf is the minimum fluidisation velocity for a bed of particles. An increase in the superficial gas velocity from 2 Umf to 2.5 Umf results in (all velocities are smaller than the entrainment velocity of the particles) nochange in the(A) Drag on particles(B) Drag on column walls(C) Bed height(D) Bed voidage

Description : Umf is the minimum fluidisation velocity for a bed of particles. An increase in the superficial gas velocity from 2 Umf to 2.5 Umf results in (all velocities are smaller than the entrainment velocity of the particles ... (A) Drag on particles (B) Drag on column walls (C) Bed height (D) Bed voidage

Last Answer : (C) Bed height

Binary distillation involves the mass transfer by __________ at the gas￾liquid interface. (A) Unidirectional diffusion from liquid to gas phase (B) Unidirectional diffusion from gas to liquid phase (C) Either 'a' or 'b' (D) A counter diffusion at an almost equal molar rate

Description : Binary distillation involves the mass transfer by __________ at the gas￾liquid interface. (A) Unidirectional diffusion from liquid to gas phase (B) Unidirectional diffusion from gas to liquid phase (C) Either 'a' or 'b' (D) A counter diffusion at an almost equal molar rate

Last Answer : (D) A counter diffusion at an almost equal molar rate

Inside the distillation column, the (A) Driving force for the vapour flow is the pressure drop (B) Liquids are not always at their bubble points (C) Pressure increases gradually from bottom to the top of the column (D) None of these

Description : Inside the distillation column, the (A) Driving force for the vapour flow is the pressure drop (B) Liquids are not always at their bubble points (C) Pressure increases gradually from bottom to the top of the column (D) None of these

Last Answer : (A) Driving force for the vapour flow is the pressure drop

For the same process conditions, the reflux ratio of an unlagged distillation column (A) Decreases in winter (B) Increases in winter (C) Increases in summer (D) None of these

Description : For the same process conditions, the reflux ratio of an unlagged distillation column (A) Decreases in winter (B) Increases in winter (C) Increases in summer (D) None of these

Last Answer : (B) Increases in winter

. In a distillation column, with increase in the reflux ratio, the heat removed in the cooler (A) Increases (B) Decreases (C) Remains unaffected (D) And the heat required in reboiler decreases

Description : . In a distillation column, with increase in the reflux ratio, the heat removed in the cooler (A) Increases (B) Decreases (C) Remains unaffected (D) And the heat required in reboiler decreases

Last Answer : (A) Increases

For a fixed number of ideal stages in a distillation column, as the reflux ratio is increased, the difference in composition between the top and bottomproduct streams(A) Increases(B) Decreases(C) Remain unaffected(D) Passes through a maximum

Description : For a fixed number of ideal stages in a distillation column, as the reflux ratio is increased, the difference in composition between the top and bottom product streams (A) Increases (B) Decreases (C) Remain unaffected (D) Passes through a maximum

Last Answer : (A) Increases

In stripping section of continuous distillation column, the (A) Liquid is stripped of high boiler (B) Liquid is enriched with high boiler (C) Vapour is stripped of low boiler (D) None of these

Description : In stripping section of continuous distillation column, the (A) Liquid is stripped of high boiler (B) Liquid is enriched with high boiler (C) Vapour is stripped of low boiler (D) None of these

Last Answer : (B) Liquid is enriched with high boiler

In rectifying section of a continuous distillation column, the (A) Vapour is enriched with low boilers (B) Vapour is enriched with high boilers (C) Liquid is stripped of high boilers (D) None of these

Description : In rectifying section of a continuous distillation column, the (A) Vapour is enriched with low boilers (B) Vapour is enriched with high boilers (C) Liquid is stripped of high boilers (D) None of these

Last Answer : (B) Vapour is enriched with high boilers

If an industry is characterized by economies of scale then - (1) barriers to entry are not very large (2) long run unit costs of production decreases as the quantity the firm produces increases (3) capital requirement are small due to the efficiency of the large scale operation (4) the costs of entry into the market are likely to be substantial

Description : If an industry is characterized by economies of scale then - (1) barriers to entry are not very large (2) long run unit costs of production decreases as the quantity the firm produces increases (3) ... of the large scale operation (4) the costs of entry into the market are likely to be substantial

Last Answer : (2) long run unit costs of production decreases as the quantity the firm produces increases Explanation: In microeconomics, economies of scale are the cost advantages that an enterprise obtains due to expansion ... in unit cost as the size of a facility and the usage levels of other inputs increase.

If an industry is characterised by economies of scale then (1) barriers to entry are not very large (2) long run unit costs of production decreases as the quantity the firm produces increases (3) capital requirement are small due to the efficiency of the large scale operation (4) the costs of entry into the market are likely to be substantial

Description : If an industry is characterised by economies of scale then (1) barriers to entry are not very large (2) long run unit costs of production decreases as the quantity the firm produces increases (3) ... of the large scale operation (4) the costs of entry into the market are likely to be substantial 

Last Answer : long run unit costs of production decreases as the quantity the firm produces increases

High pressure at the bottom of a distillation tower handling heat sensitive materials results in (A) Thermal decomposition of bottoms (B) Increased relative volatility (C) Erosion of the tower (D) Very efficient operation

Description : High pressure at the bottom of a distillation tower handling heat sensitive materials results in (A) Thermal decomposition of bottoms (B) Increased relative volatility (C) Erosion of the tower (D) Very efficient operation

Last Answer : (A) Thermal decomposition of bottoms

Which of the following is the most controlling factor for the rate of bubble detachment from the hot solid surface? (A) Liquid density (B) Liquid viscosity (C) Hot surface temperature (D) Interfacial tension

Description : Which of the following is the most controlling factor for the rate of bubble detachment from the hot solid surface? (A) Liquid density (B) Liquid viscosity (C) Hot surface temperature (D) Interfacial tension

Last Answer : (D) Interfacial tension

Spontaneous combustion of coal on storage results due to(A) Inadequate ventilation (B) Low temperature oxidation (C) Storage in large heaps with small surface to volume ratio (D) All (A), (B) and (C)

Description : Spontaneous combustion of coal on storage results due to (A) Inadequate ventilation (B) Low temperature oxidation (C) Storage in large heaps with small surface to volume ratio (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

With increase in the liquid flow rate at a fixed gas velocity in a randomly packed counter current gas-liquid absorption column, the gas pressure drop (A) Decreases (B) Remains unchanged (C) Increases (D) Decreases exponentially

Description : With increase in the liquid flow rate at a fixed gas velocity in a randomly packed counter current gas-liquid absorption column, the gas pressure drop (A) Decreases (B) Remains unchanged (C) Increases (D) Decreases exponentially

Last Answer : (C) Increases

Momentum transfer in laminar flow of fluids results due to the (A) Viscosity (B) Density (C) Velocity gradient (D) None of these

Description : Momentum transfer in laminar flow of fluids results due to the (A) Viscosity (B) Density (C) Velocity gradient (D) None of these

Last Answer : (C) Velocity gradient

In a Rankine cycle, regeneration results in higher efficiency because (a) Pressure inside the boiler increases [GATE-2003] (b) Heat is added before steam enters the low pressure turbine (c) Average temperature of heat addition in the boiler increases (d) Total work delivered by the turbine increases

Description : In a Rankine cycle, regeneration results in higher efficiency because (a) Pressure inside the boiler increases [GATE-2003] (b) Heat is added before steam enters the low pressure turbine (c) ... temperature of heat addition in the boiler increases (d) Total work delivered by the turbine increases 

Last Answer : (c) Average temperature of heat addition in the boiler increases  

The interfacial area per unit volume of dispersion, in a gas-liquid contactor, for fractional hold up of gas = 0.1 and gas bubble diameter = 0.5 mm is given by (in m2 /m3 ) (A) 500 (B) 1200 (C) 900 (D) 800

Description : The interfacial area per unit volume of dispersion, in a gas-liquid contactor, for fractional hold up of gas = 0.1 and gas bubble diameter = 0.5 mm is given by (in m2 /m3 ) (A) 500 (B) 1200 (C) 900 (D) 800

Last Answer : (A) 500

Hydrogenation of oil is carried out in a/an __________ in Vanaspati manufacturing plant. (A) Agitated vessel (B) Sieve tray column (C) Bubble cap column (D) Packed tower

Description : Hydrogenation of oil is carried out in a/an __________ in Vanaspati manufacturing plant. (A) Agitated vessel (B) Sieve tray column (C) Bubble cap column (D) Packed tower

Last Answer : (A) Agitated vessel