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)

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)
by

1 Answer

Answer :

(D) Both (B) and (C)
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

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

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

In a moderately sized packed absorption tower, channelling (which is most severe with stacked packings) can be minimised by taking the ratio of tower diameter to packing diameter (A) > 4 :1 (B) < 8 : 1 (C) > 8:1 (D) < 6:1

Description : In a moderately sized packed absorption tower, channelling (which is most severe with stacked packings) can be minimised by taking the ratio of tower diameter to packing diameter (A) > 4 :1 (B) < 8 : 1 (C) > 8:1 (D) < 6:1

Last Answer : (C) > 8:1

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

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

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

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)

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 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)

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

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

Description : 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 ... C) Low pressure drop and low hold up (D) High pressure drop and high hold up

Last Answer : (C) Low pressure drop and low hold up

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

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

For a packed bed reactor; the presence of a long tail in the residence time distribution curve is an indication of: (A) Ideal plug flow (B) Bypass (C) Dead zone (D) Channelling

Description : For a packed bed reactor; the presence of a long tail in the residence time distribution curve is an indication of: (A) Ideal plug flow (B) Bypass (C) Dead zone (D) Channelling

Last Answer : (C) Dead zone

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

An ideal tower packing should not (A) Have low weight per unit volume (B) Have large surface area per unit volume (C) Have large free cross-section (D) Hold up large amount of liquid in the packing

Description : An ideal tower packing should not (A) Have low weight per unit volume (B) Have large surface area per unit volume (C) Have large free cross-section (D) Hold up large amount of liquid in the packing

Last Answer : (D) Hold up large amount of liquid in the packing

Which of the following is an undesirable property in a tower packing? (A) Large surface per unit volume (B) Large free cross-section (C) Low weight per unit volume (D) Large weight of liquid retained

Description : Which of the following is an undesirable property in a tower packing? (A) Large surface per unit volume (B) Large free cross-section (C) Low weight per unit volume (D) Large weight of liquid retained

Last Answer : (D) Large weight of liquid retained

Fluidised bed reactor is characterised by (A) Uniformity of temperature (B) Comparatively smaller equipment (C) Very small pressure drop (D) Absence of continuous catalyst regeneration facility

Description : Fluidised bed reactor is characterised by (A) Uniformity of temperature (B) Comparatively smaller equipment (C) Very small pressure drop (D) Absence of continuous catalyst regeneration facility

Last Answer : (A) Uniformity of temperature

Which of the following gas-liquid contacting devices incurs the least pressure drop for a particular duty? (A) Grid tray tower (B) Perforated tray tower (C) Wetted wall tower (D) Bubble cap tower

Description : Which of the following gas-liquid contacting devices incurs the least pressure drop for a particular duty? (A) Grid tray tower (B) Perforated tray tower (C) Wetted wall tower (D) Bubble cap tower

Last Answer : (D) Bubble cap tower

Stacked packing compared to dumped packing (A) Provides poorer contact between the fluids (B) Gives lower pressure drop (C) Both (A) and (B) (D) Gives higher pressure drop

Description : Stacked packing compared to dumped packing (A) Provides poorer contact between the fluids (B) Gives lower pressure drop (C) Both (A) and (B) (D) Gives higher pressure drop

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

Out of the following, the lowest packing of atoms exists in __________ crystal lattice structure. (A) Hexagonal close, packed (hcp) (B) Face centred cubic (fcc) (C) Body centred cubic (bcc) (D) Simple cubic

Description : Out of the following, the lowest packing of atoms exists in __________ crystal lattice structure. (A) Hexagonal close, packed (hcp) (B) Face centred cubic (fcc) (C) Body centred cubic (bcc) (D) Simple cubic

Last Answer : (D) Simple cubic

(1) they contain free electrons Explanation: Metals typically consist of closepacked atoms, meaning that the atoms are arranged like closely packed spheres. Two packing motifs are common, one being bodycentered cubic wherein each metal atom is surrounded by eight equivalent atoms. The other main motif is face-centered cubic where the metal atoms are surrounded by six neighboring atoms. Several metals adopt both structures, depending on the temperature.

Description : (1) they contain free electrons Explanation: Metals typically consist of closepacked atoms, meaning that the atoms are arranged like closely packed spheres. Two packing motifs are common, one ... surrounded by six neighboring atoms. Several metals adopt both structures, depending on the temperature.

Last Answer : Helium gas is filled in ballons because (1) its atomic number is 2 (2) it is lighter than air (3) it is one of the constitutents of water (4) it is a noble gas

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

For absorbers, high pressure drop results in (A) Increased efficiency (B) Decreased efficiency (C) High operating cost (D) Better gas liquid contact

Description : For absorbers, high pressure drop results in (A) Increased efficiency (B) Decreased efficiency (C) High operating cost (D) Better gas liquid contact

Last Answer : (C) High operating cost

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

In a packed absorption tower, if the equilibrium and operating lines are both straight lines, then the ratio, HETP/HTUOG __________ the absorption factor. (A) Increases with increase in (B) Is one at unity value of (C) Both (A) and (B) (D) Neither (A) nor (B)

Description : In a packed absorption tower, if the equilibrium and operating lines are both straight lines, then the ratio, HETP/HTUOG __________ the absorption factor. (A) Increases with increase in (B) Is one at unity value of (C) Both (A) and (B) (D) Neither (A) nor (B)

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

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)

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)

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

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

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

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

Diameter of raschig rings used in packed tower in industry is normally around __________ inches. (A) 2 (B) 8 (C) 12 (D) 18

Description : Diameter of raschig rings used in packed tower in industry is normally around __________ inches. (A) 2 (B) 8 (C) 12 (D) 18

Last Answer : (A) 2

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

Operating velocity in a packed tower is usually __________ the flooding velocity. (A) Half (B) Twice (C) Equal to (D) More than

Description : Operating velocity in a packed tower is usually __________ the flooding velocity. (A) Half (B) Twice (C) Equal to (D) More than

Last Answer : (A) Half

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

Dried finished product sampled from various parts of a __________ dryer exhibits non-uniformity in the moisture content. (A) Rotary (B) Tray (C) Freeze (D) None of these

Description : Dried finished product sampled from various parts of a __________ dryer exhibits non-uniformity in the moisture content. (A) Rotary (B) Tray (C) Freeze (D) None of these

Last Answer : (B) Tray

What causes convective acceleration in fluid flow? (A) Steep slope in flow (B) Unsteady nature of flow (C) Non-uniformity of flow (D) Turbulence in flow

Description : What causes convective acceleration in fluid flow? (A) Steep slope in flow (B) Unsteady nature of flow (C) Non-uniformity of flow (D) Turbulence in flow

Last Answer : (C) Non-uniformity of flow

. __________ 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