The reason for preferring packed towers over plate towers in distillation practice is that the packed tower operation gives (A) Low pressure drop and high hold up (B) High pressure drop and low hold up (C) Low pressure drop and low hold up (D) High pressure drop and high hold up

The reason for preferring packed towers over plate towers in

distillation practice is that the packed tower operation gives

(A) Low pressure drop and high hold up

(B) High pressure drop and low hold up

(C) Low pressure drop and low hold up

(D) High pressure drop and high hold up


by

1 Answer

Answer :

(C) Low pressure drop and low hold up

by

Related questions

Pick out the wrong statement. (A) Packed towers are preferred for vacuum operation, because the pressure drop through the packing is less and they (packings) also lessen the possibility of tower wall collapse (B) Packed towers are preferred over plate towers for handling corrosive and foamy liquids (C) Diameter of randomly packed tower is normally more than 1.2 metres (D) Due to uneven supply and improper distribution of liquid, problem of channelling, loading & flooding is generally encountered in packed towers

Description : Pick out the wrong statement. (A) Packed towers are preferred for vacuum operation, because the pressure drop through the packing is less and they (packings) also lessen the ... of liquid, problem of channelling, loading & flooding is generally encountered in packed towers

Last Answer : (C) Diameter of randomly packed tower is normally more than 1.2 metres

The main reason for dividing a tall packed tower into series of small towers is to (A) Minimise the overall pressure drop (B) Avoid flooding (C) Reduce liquid hold up (D) Avoid channelling

Description : The main reason for dividing a tall packed tower into series of small towers is to (A) Minimise the overall pressure drop (B) Avoid flooding (C) Reduce liquid hold up (D) Avoid channelling

Last Answer : (D) Avoid channelling

Plate towers are preferred to packed towers, when large temperature changes are involved, because of the reason that the (A) Packing may be crushed due to thermal expansion/contraction of the components of the equipments (B) Pressure drop in the equipment will be very high (C) Viscosity variation of the fluids may cause channelling/flooding (D) None of these

Description : Plate towers are preferred to packed towers, when large temperature changes are involved, because of the reason that the (A) Packing may be crushed due to thermal expansion/contraction of the ... C) Viscosity variation of the fluids may cause channelling/flooding (D) None of these

Last Answer : (A) Packing may be crushed due to thermal expansion/contraction of the components of the equipments

Pick out the correct statement. (A) For identical gas flow rates, less pressure drop occurs through a plate tower than through a packed tower (B) Plate column can handle greater liquid loads without flooding than packed column, but the liquid hold up is more in the case of plate column (C) For the same duty, plate columns weigh less than packed columns (D) All (A), (B) and (C)

Description : Pick out the correct statement. (A) For identical gas flow rates, less pressure drop occurs through a plate tower than through a packed tower (B) Plate column can handle greater liquid loads without flooding than packed ... duty, plate columns weigh less than packed columns (D) All (A), (B) and (C)

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

A packed tower compared to a plate tower for a particular mass transfer operation (A) Incurs smaller pressure drop (B) Allows installation of cooling coils (C) Is less costly when built in large sizes/diameters (D) Is more suitable, if suspended solids are present in fluid stream

Description : A packed tower compared to a plate tower for a particular mass transfer operation (A) Incurs smaller pressure drop (B) Allows installation of cooling coils (C) Is less costly when built in large sizes/diameters (D) Is more suitable, if suspended solids are present in fluid stream

Last Answer : (A) Incurs smaller pressure drop

Use of packed towers for distillation is generally limited to the (A) Small sizes (B) Multi-component distillation (C) High pressure operation (D) Vacuum distillation

Description : Use of packed towers for distillation is generally limited to the (A) Small sizes (B) Multi-component distillation (C) High pressure operation (D) Vacuum distillation

Last Answer : (A) Small sizes

Very tall packed towers are divided into series of beds to (A) Reduce the overall pressure drop (B) Avoid channelling (C) Reduce liquid hold-up (D) Avoid flooding

Description : Very tall packed towers are divided into series of beds to (A) Reduce the overall pressure drop (B) Avoid channelling (C) Reduce liquid hold-up (D) Avoid flooding

Last Answer : (B) Avoid channelling

Pressure drop through plate tower as compared to that through packed tower, for the same duty will be (A) Less (B) More (C) Equal (D) Either (A) or (B); depends on the packing height

Description : Pressure drop through plate tower as compared to that through packed tower, for the same duty will be (A) Less (B) More (C) Equal (D) Either (A) or (B); depends on the packing height

Last Answer : (B) More

Which of the following same diameter columns gives lowest pressure drop per unit height? (A) Bubble-cap column (B) Sieve-plate column (C) Packed column (stacked)

Description : Which of the following same diameter columns gives lowest pressure drop per unit height? (A) Bubble-cap column (B) Sieve-plate column (C) Packed column (stacked)

Last Answer : (C) Packed column (stacked)

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

Pick out the wrong statement. (A) With decrease in feed temperature, the number of plates required for binary distillation decreases for a given ‘L/V’ ratio (B) The extraction per unit of total height for a short packed column is more effective than for a tall column, in case of liquid-liquid extraction(C) Natural draft cooling towers are made of ferroconcrete and its cross￾section is wider at the bottom(D) Vander wall adsorption is also called chemisorption

Description : Pick out the wrong statement. (A) With decrease in feed temperature, the number of plates required for binary distillation decreases for a given L/V' ratio (B) The extraction per unit ... and its cross￾section is wider at the bottom (D) Vander wall adsorption is also called chemisorption

Last Answer : (D) Vander wall adsorption is also called chemisorption

Channelling in a packed tower results from the (A) High pressure drop (B) Maldistribution of liquid (C) Non-uniformity of packing (D) Both (B) and (C)

Description : Channelling in a packed tower results from the (A) High pressure drop (B) Maldistribution of liquid (C) Non-uniformity of packing (D) Both (B) and (C)

Last Answer : (D) Both (B) and (C)

Under conditions of flooding in packed tower, the gas pressure drop (A) Decreases rapidly (B) Increases rapidly (C) Remain constant (D) Is maximum

Description : Under conditions of flooding in packed tower, the gas pressure drop (A) Decreases rapidly (B) Increases rapidly (C) Remain constant (D) Is maximum

Last Answer : (D) Is maximum

Out of the following gas-liquid contacting devices, for a given set of operating conditions, gas pressure drop is the least in __________ tower. (A) Wetted wall (B) Bubble cap (C) Perforated tray (D) Packed

Description : Out of the following gas-liquid contacting devices, for a given set of operating conditions, gas pressure drop is the least in __________ tower. (A) Wetted wall (B) Bubble cap (C) Perforated tray (D) Packed

Last Answer : (A) Wetted wall

At the same gas flow rate, the pressure drop in a packed tower being irrigated with liquid __________ that in dry packed tower. (A) Is greater than (B) Is lower than (C) Is same as (D) Cannot be predicted as data are insufficient

Description : At the same gas flow rate, the pressure drop in a packed tower being irrigated with liquid __________ that in dry packed tower. (A) Is greater than (B) Is lower than (C) Is same as (D) Cannot be predicted as data are insufficient

Last Answer : (A) Is greater than

Which one of the following devices is not used for both the absorption as well as the liquid-liquid extraction processes? (A) Packed towers(B) Plate towers(C) Spray towers(D) Wetted wall columns

Description : Which one of the following devices is not used for both the absorption as well as the liquid-liquid extraction processes? (A) Packed towers (B) Plate towers (C) Spray towers (D) Wetted wall columns

Last Answer : (D) Wetted wall columns

Even though bubble cap towers are very effective for humidification operation, they are not used commonly in industries, because of the (A) High evaporation losses of water (B) High pressure drop of the gas (C) Difficulty in its fabrication (D) None of these

Description : Even though bubble cap towers are very effective for humidification operation, they are not used commonly in industries, because of the (A) High evaporation losses of water (B) High pressure drop of the gas (C) Difficulty in its fabrication (D) None of these

Last Answer : (B) High pressure drop of the gas

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 these columns incurs the lowest pressure drop? (A) Packed column (with stacked packing) (B) Packed column (with dumped packing) (C) Bubble plate column (D) Pulse column

Description : Which of these columns incurs the lowest pressure drop? (A) Packed column (with stacked packing) (B) Packed column (with dumped packing) (C) Bubble plate column (D) Pulse column

Last Answer : (A) Packed column (with stacked packing)

SO3 is absorbed using H2SO4 in a (A) Cast iron packed tower (B) Stainless steel plate tower (C) Packed steel tower lined with acid proof bricks (D) None of these

Description : SO3 is absorbed using H2SO4 in a (A) Cast iron packed tower (B) Stainless steel plate tower (C) Packed steel tower lined with acid proof bricks (D) None of these

Last Answer : (C) Packed steel tower lined with acid proof bricks

In a packed tower, the value of HETP equals HTUOG, when the equilibrium and the operating lines are (where, HETP = height equivalent to a theoretical plate HTUOG = overall gas phase height of a transfer unit). (A) Straight (B) Parallel (C) Both (A) & (B) (D) Neither (A) nor (B

Description : In a packed tower, the value of HETP equals HTUOG, when the equilibrium and the operating lines are (where, HETP = height equivalent to a theoretical plate HTUOG = overall gas phase height of a transfer unit). (A) Straight (B) Parallel (C) Both (A) & (B) (D) Neither (A) nor (B

Last Answer : (C) Both (A) & (B)

Sodium bicarbonate is produced during soda ash manufacture using a __________ tower. (A) Plate (B) Baffle (C) Packed (D) None of these

Description : Sodium bicarbonate is produced during soda ash manufacture using a __________ tower. (A) Plate (B) Baffle (C) Packed (D) None of these

Last Answer : (B) Baffle

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

Perforated plate towers are unique for solvent extraction because, they provide (A) Higher contact area (B) Better contact of the phase (C) Repeated coalescence & redispersion of the drop phase (D) None of these

Description : Perforated plate towers are unique for solvent extraction because, they provide (A) Higher contact area (B) Better contact of the phase (C) Repeated coalescence & redispersion of the drop phase (D) None of these

Last Answer : (C) Repeated coalescence & redispersion of the drop phase

Pick out the wrong statement. (A) Different solids have different equilibrium moisture curves (B) Total condenser or reboiler is considered equivalent to one theoretical plate in McCabe-Thiele method of theoretical plate calculation for distillation column (C) Heat removal load on cooler remains constant, even with increase of the reflux ratio in a distillation column (D) Even a forced draft cooling tower cannot cool water below the wet bulb temperature

Description : Pick out the wrong statement. (A) Different solids have different equilibrium moisture curves (B) Total condenser or reboiler is considered equivalent to one theoretical plate in McCabe-Thiele method of ... (D) Even a forced draft cooling tower cannot cool water below the wet bulb temperature

Last Answer : (C) Heat removal load on cooler remains constant, even with increase of the reflux ratio in a distillation column

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

Can the efficiency of a plate in the distillation tower be greater than 100%? (A) Yes (B) Normally not; but is possible if infinite number of plates are put(C) Never(D) Yes; if the reflux ratio is maximum

Description : Can the efficiency of a plate in the distillation tower be greater than 100%? (A) Yes (B) Normally not; but is possible if infinite number of plates are put (C) Never (D) Yes; if the reflux ratio is maximum

Last Answer : (C) Never

Pick out the correct statement. (A) Higher hold up of the solid in the rotary dryer results in better exposure of the solids to the gas (B) The 'Hatta number' is important in problems involving gas absorption without chemical reaction (C) For a non-reacting binary mixture of ideal gases, the partial pressure distribution of both components is linear in the case of steady state equimolal counter-diffusion (D) Total reflux in case of distillation operation requires infinite number of plates for a binary system separation

Description : Pick out the correct statement. (A) Higher hold up of the solid in the rotary dryer results in better exposure of the solids to the gas (B) The 'Hatta number' is ... reflux in case of distillation operation requires infinite number of plates for a binary system separation

Last Answer : (C) For a non-reacting binary mixture of ideal gases, the partial pressure distribution of both components is linear in the case of steady state equimolal counter-diffusion

Which of the following is the most suitable for extraction in a system having very low density difference? (A) Mixer-settler extractor (B) Centrifugal extractor (C) Pulsed extractor (D) Packed extraction tower

Description : Which of the following is the most suitable for extraction in a system having very low density difference? (A) Mixer-settler extractor (B) Centrifugal extractor (C) Pulsed extractor (D) Packed extraction tower

Last Answer : (B) Centrifugal extractor

Pick out the wrong statement pertaining to the cooling towers. (A) In case of induced draft cooling tower, the fan is placed at the top of the tower (B) Effectiveness of forced draft cooling tower is reduced by the recirculation of the humid and hot discharged air (C) A natural draft cooling tower is recommended to be used, when the air humidity is low and air temperature is also low (D) Effectiveness of a mechanical draft cooling tower is reduced with increase in air wet-bulb temperature

Description : Pick out the wrong statement pertaining to the cooling towers. (A) In case of induced draft cooling tower, the fan is placed at the top of the tower (B) Effectiveness of ... Effectiveness of a mechanical draft cooling tower is reduced with increase in air wet-bulb temperature

Last Answer : (D) Effectiveness of a mechanical draft cooling tower is reduced with increase in air wet-bulb temperature

Pick out the wrong statement: (A) Change in barometric pressure does not affect the relative humidity (B) In case of a packed tower, the operating velocity is about half of the flooding velocity, generally (C) 'Elution' means the desorption of the adsorbed solute by a solvent (D) The equilibrium moisture content of the solid can be reduced by increasing the absolute humidity

Description : Pick out the wrong statement: (A) Change in barometric pressure does not affect the relative humidity (B) In case of a packed tower, the operating velocity is about half of the ... (D) The equilibrium moisture content of the solid can be reduced by increasing the absolute humidity

Last Answer : (D) The equilibrium moisture content of the solid can be reduced by increasing the absolute humidity

Pressure maintained in the high pressure primary tower of a three stage crude oil distillation system is about __________ kg/cm2 . (A) 1.5 (B) 3 (C) 6 (D) 12

Description : Pressure maintained in the high pressure primary tower of a three stage crude oil distillation system is about __________ kg/cm2 . (A) 1.5 (B) 3 (C) 6 (D) 12

Last Answer : (B) 3

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

Which of the following equipments is not used in liquid-liquid extraction? (A) Pachuka tank (B) Agitated vessels (C) Centrifugal extractors (D) Packed towers

Description : Which of the following equipments is not used in liquid-liquid extraction? (A) Pachuka tank (B) Agitated vessels (C) Centrifugal extractors (D) Packed towers

Last Answer : (A) Pachuka tank

Which of the following equipments is not used for liquid dispersion? (A) Wetted wall towers (B) Packed towers (C) Venturi scrubbers (D) Agitated vessels

Description : Which of the following equipments is not used for liquid dispersion? (A) Wetted wall towers (B) Packed towers (C) Venturi scrubbers (D) Agitated vessels

Last Answer : (D) Agitated vessels

Channelling is most severe (A) In towers packed with stacked packing (B) In towers packed randomly with crushed solids (C) In dumped packing of regular units

Description : Channelling is most severe (A) In towers packed with stacked packing (B) In towers packed randomly with crushed solids (C) In dumped packing of regular units

Last Answer : (A) In towers packed with stacked packing

The primary reason for preferring phentolamine as the α adrenergic blocker for performing diagnostic test for pheochromocytoma is: A. It produces rapid and short lasting α-adrenergic blockade B. It equally blocks α1 and α2 adrenoceptors C. It is the most potent α blocker D. It has no additional β adrenergic blocking property

Description : The primary reason for preferring phentolamine as the α adrenergic blocker for performing diagnostic test for pheochromocytoma is: A. It produces rapid and short lasting α-adrenergic blockade B. It equally ... It is the most potent α blocker D. It has no additional β adrenergic blocking property

Last Answer : A. It produces rapid and short lasting α-adrenergic blockade

The primary reason for preferring phentolamine as the α adrenergic blocker for performing diagnostic test for pheochromocytoma is: A. It produces rapid and short lasting α-adrenergic blockade B. It equally blocks α1 and α2 adrenoceptors C. It is the most potent α blocker D. It has no additional β adrenergic blocking property

Description : The primary reason for preferring phentolamine as the α adrenergic blocker for performing diagnostic test for pheochromocytoma is: A. It produces rapid and short lasting α-adrenergic blockade B. It equally ... It is the most potent α blocker D. It has no additional β adrenergic blocking property

Last Answer : A. It produces rapid and short lasting α-adrenergic blockade

Use of raschig rings in place of crushed stones as packing in packed beds (other things being same) (A) Increases pressure drop, increases surface area (B) Increases pressure drop, decreases surface area (C) Decreases pressure drop, increases surface area (D) Decreases pressure drop, decreases surface area

Description : Use of raschig rings in place of crushed stones as packing in packed beds (other things being same) (A) Increases pressure drop, increases surface area (B) Increases pressure drop, decreases ... (C) Decreases pressure drop, increases surface area (D) Decreases pressure drop, decreases surface area

Last Answer : (C) Decreases pressure drop, increases surface area

In a packed bed absorption column, the channelling will be noted by the (A) Increase in flow rate (B) Sharp drop in pressure drop (C) Sharp rise in pressure drop (D) None of these

Description : In a packed bed absorption column, the channelling will be noted by the (A) Increase in flow rate (B) Sharp drop in pressure drop (C) Sharp rise in pressure drop (D) None of these

Last Answer : (B) Sharp drop in pressure drop

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

A gas (density = 1.5 kg/m3 , viscosity = 2 × 10 ‒5 kg/m.s) flowing through a packed bed (particle size = 0.5 cm, porosity = 0.5) at a superficial velocity of 2 m/s causes a pressure drop of 8400 Pa/m. The pressure drop for another gas, with density of 1.5 kg/m3and viscosity of 3 × 10 ‒5kg/m.s flowing at 3 m/s will be (A) 8400 Pa/m (B) 12600 Pa/m (C) 18900 Pa/m (D) 16800 Pa/m

Description : A gas (density = 1.5 kg/m3 , viscosity = 2 10 -5 kg/m.s) flowing through a packed bed (particle size = 0.5 cm, porosity = 0.5) at a superficial velocity of 2 m/s causes a pressure drop of 8400 Pa/m. The ... flowing at 3 m/s will be (A) 8400 Pa/m (B) 12600 Pa/m (C) 18900 Pa/m (D) 16800 Pa/m

Last Answer : (B) 12600 Pa/m

For flow of fluids through packed bed, the superficial velocity is (A) Less than the average velocity through channels (B) More than the average velocity through channels (C) Dependent on the pressure drop across the bed (D) Same as the average velocity through channels

Description : For flow of fluids through packed bed, the superficial velocity is (A) Less than the average velocity through channels (B) More than the average velocity through channels (C) Dependent on the pressure drop across the bed (D) Same as the average velocity through channels

Last Answer : (A) Less than the average velocity through channels

Pressure drop in a packed bed for laminar flow is given by the __________ equation. (A) Kozeny-Carman (B) Blake-Plummer (C) Leva's (D) Fanning friction factor

Description : Pressure drop in a packed bed for laminar flow is given by the __________ equation. (A) Kozeny-Carman (B) Blake-Plummer (C) Leva's (D) Fanning friction factor

Last Answer : (A) Kozeny-Carman

In a dry packed bed, the pressure drop will be changed by increasing the flow rate as (A) V1.8 (B) V-0.8 (C) V (D) V-1

Description : In a dry packed bed, the pressure drop will be changed by increasing the flow rate as (A) V1.8 (B) V-0.8 (C) V (D) V-1

Last Answer : (A) V1.8

For laminar flow of a fluid through a packed bed of spheres of diameter d, the pressure drop per unit length of bed depends upon the sphere diameter as (A) d (B) d 2 (C) d 4 (D) d

Description : For laminar flow of a fluid through a packed bed of spheres of diameter d, the pressure drop per unit length of bed depends upon the sphere diameter as (A) d (B) d 2 (C) d 4 (D) d

Last Answer : (D) d

Pressure drop in packed bed for turbulent flow is given by the __________ equation. (A) Kozeny-Carman (B) Blake-Plummer (C) Leva's (D) Hagen-Poiseuille’s

Description : Pressure drop in packed bed for turbulent flow is given by the __________ equation. (A) Kozeny-Carman (B) Blake-Plummer (C) Leva's (D) Hagen-Poiseuille’s

Last Answer : (B) Blake-Plummer

Pressure drop in a fluidised bed reactor is __________ that in a similar packed bed reactor. (A) Less than (B) Greater than (C) Same as (D) None of these

Description : Pressure drop in a fluidised bed reactor is __________ that in a similar packed bed reactor. (A) Less than (B) Greater than (C) Same as (D) None of these

Last Answer : (B) Greater than

The solvent used in liquid extraction should not have high latent heat of vaporisation, because (A) The pressure drop and hence the pumping cost will be very high (B) It cannot be recovered by distillation (C) Its recovery cost by distillation may be prohibitively high (D) It will decompose while recovering by distillation

Description : The solvent used in liquid extraction should not have high latent heat of vaporisation, because (A) The pressure drop and hence the pumping cost will be very high (B) It cannot ... by distillation may be prohibitively high (D) It will decompose while recovering by distillation

Last Answer : (C) Its recovery cost by distillation may be prohibitively high