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

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

by

1 Answer

Answer :

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


by

Related questions

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

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

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

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)

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

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)

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 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

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

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

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

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

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

Pick out the wrong statement about cavitation. (A) Sudden reduction of pressure in a fluid flow system caused by flow separation, vortex formation or abrupt closing of valve leads to cavitation (B) Cavitation may be caused due to boiling of liquid by decreasing the pressure resulting in formation & collapse of vapor cavities (C) Cavitation begins at higher static pressure and lower velocity in larger diameter pipelines resulting in audible noise(D) Large scale cavitation cannot damage pipeline, restrict fluid flow anddamage steam turbine blades

Description : Pick out the wrong statement about cavitation. (A) Sudden reduction of pressure in a fluid flow system caused by flow separation, vortex formation or abrupt closing of valve leads to cavitation ... (D) Large scale cavitation cannot damage pipeline, restrict fluid flow and damage steam turbine blades

Last Answer : (D) Large scale cavitation cannot damage pipeline, restrict fluid flow and damage steam turbine blades

Pick out the wrong statement: (A) The capacity of an evaporator is reduced by the boiling point elevation (B) Corrosive liquid is normally passed through the tubes in a shell and tube heat exchanger (C) Steam jet ejector is used for vapor compression in a thermal recompression evaporator (D) Heat sensitive materials should be concentrated in high pressure evaporators

Description : Pick out the wrong statement: (A) The capacity of an evaporator is reduced by the boiling point elevation (B) Corrosive liquid is normally passed through the tubes in a ... recompression evaporator (D) Heat sensitive materials should be concentrated in high pressure evaporators

Last Answer : (D) Heat sensitive materials should be concentrated in high pressure evaporators

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

Which of the following liquid-vapor contacting devices provides maximum contact surface area for a particular duty? (A) Sieve plate column (B) Bubble cap column (C) Randomly packed column (D) Wetted wall column

Description : Which of the following liquid-vapor contacting devices provides maximum contact surface area for a particular duty? (A) Sieve plate column (B) Bubble cap column (C) Randomly packed column (D) Wetted wall column

Last Answer : (D) Wetted wall column

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)

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

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 wrong statement: (A) Greater is the kinematic viscosity of the liquid, greater is the thickness of the boundary layer (B) Blowers develop a maximum pressure of 2 atmospheres (C) Friction losses in pipe fittings are generally expressed in terms of velocity heads (D) Fanning friction factor in case of turbulent flow of liquids in pipe depends upon relative roughness & Reynolds number

Description : Pick out the wrong statement: (A) Greater is the kinematic viscosity of the liquid, greater is the thickness of the boundary layer (B) Blowers develop a maximum pressure of 2 atmospheres ( ... factor in case of turbulent flow of liquids in pipe depends upon relative roughness & Reynolds number

Last Answer : (C) Friction losses in pipe fittings are generally expressed in terms of velocity heads

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

In an operating distillation column, the (A) Vapors and liquids are at their dew point and bubble point respectively (B) Driving force for the liquid flow is its specific weight (C) Driving force for the vapor flow is the pressure drop, as the pressure decreases gradually from the bottom to the top of the column (D) Highest temperature is encountered at the top of the column

Description : In an operating distillation column, the (A) Vapors and liquids are at their dew point and bubble point respectively (B) Driving force for the liquid flow is its specific weight (C) Driving force for ... bottom to the top of the column (D) Highest temperature is encountered at the top of the column

Last Answer : (C) Driving force for the vapor flow is the pressure drop, as the pressure decreases gradually from the bottom to the top of the column

In a gas-liquid shell and tube heat exchanger, the(A) Presence of a non-condensable gas decreases the condensing film co￾efficient (B) Gases under high pressure are routed through the tube side, because high pressure gases are corrosive in nature (C) Gases to be heated/cooled is normally routed through the shell side, because the corrosion caused by the cooling water or steam condensate remain localised to the tubes (D) All 'a', 'b' & 'c'

Description : In a gas-liquid shell and tube heat exchanger, the (A) Presence of a non-condensable gas decreases the condensing film co￾efficient (B) Gases under high pressure are routed through the tube side, because high pressure ... water or steam condensate remain localised to the tubes (D) All 'a', 'b' & 'c'

Last Answer : (D) All 'a', 'b' & 'c'

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

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

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

Pick out the wrong statement. (A) A fluid mass is free from shearing forces, when it is made to rotate with a uniform velocity(B) Newton's law of viscosity is not applicable to the turbulent flow of fluidwith linear velocity distribution(C) Laminar flow of viscous liquids is involved in the lubrication of varioustypes of bearings(D) Rise of water in capillary tubes reduces with the increasing diameter ofcapillary tubes

Description : Pick out the wrong statement. (A) A fluid mass is free from shearing forces, when it is made to rotate with a uniform velocit (B) Newton's law of viscosity is not applicable to the ... types of bearings (D) Rise of water in capillary tubes reduces with the increasing diameter of capillary tubes

Last Answer : (B) Newton's law of viscosity is not applicable to the turbulent flow of fluid with linear velocity distribution

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)

Pick out the wrong statement pertaining to the turbine agitator. (A) Recommended peripheral speed for the turbine agitator is 200-250 metres/minute (B) Pitched blade turbine agitator gives only radial flow with complete absence of the axial flow (C) Generally, the diameter of the agitator is kept between l/3rd to l/6th of the tank diameter while the blade length is l/4th of agitator diameter (with central disc, it is l/8th of the agitator diameter)

Description : Pick out the wrong statement pertaining to the turbine agitator. (A) Recommended peripheral speed for the turbine agitator is 200-250 metres/minute (B) Pitched blade turbine agitator gives only radial flow with ... l/4th of agitator diameter (with central disc, it is l/8th of the agitator diameter)

Last Answer : (B) Pitched blade turbine agitator gives only radial flow with complete absence of the axial flow

Minimum possible diameter of a packed column is decided mainly bythe(A) Flooding(B) Gas viscosity(C) Liquid density(D) Liquid hold up

Description : Minimum possible diameter of a packed column is decided mainly bythe (A) Flooding (B) Gas viscosity (C) Liquid density (D) Liquid hold up

Last Answer : (A) Flooding

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

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

Flooding in a vapor-liquid contacting equipment occurs in a tray, when the pressure drop through a tray is __________ the liquid head available in the downcomer. (A) Less than (B) More than (C) Same as (D) Very much less

Description : Flooding in a vapor-liquid contacting equipment occurs in a tray, when the pressure drop through a tray is __________ the liquid head available in the downcomer. (A) Less than (B) More than (C) Same as (D) Very much less

Last Answer : (B) More than

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

Which of the following is the most suitable filter for separation ofabrasive solids suspended in a corrosive liquid?(A) Sand bed filter(B) Plate and frame filter press(C) Vacuum filter(D) Batch basket centrifuge

Description : Which of the following is the most suitable filter for separation ofabrasive solids suspended in a corrosive liquid? (A) Sand bed filter (B) Plate and frame filter press (C) Vacuum filter (D) Batch basket centrifuge

Last Answer : (C) Vacuum filter

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

Most important factor to be considered in the selection of packings for absorbers is the __________ of packing. (A) Size (B) Durability (C) Porosity (D) Cost

Description : Most important factor to be considered in the selection of packings for absorbers is the __________ of packing. (A) Size (B) Durability (C) Porosity (D) Cost

Last Answer : (C) Porosity

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

Pick out the wrong statement. (A) Heat transfer by radiation cannot occur across an absolute volume (B) In case of a shell and tube heat exchanger, the pressure drop through the shell is proportional to the number of times the fluid crosses the bundle between baffles (C) Propagation velocity for travel of heat radiation through vacuum is equal to the velocity of the light (D) The amount of heat involved in the condensation or vaporisation of 1 kg of a fluid is the same

Description : Pick out the wrong statement. (A) Heat transfer by radiation cannot occur across an absolute volume (B) In case of a shell and tube heat exchanger, the pressure drop through the shell is ... The amount of heat involved in the condensation or vaporisation of 1 kg of a fluid is the same

Last Answer : (A) Heat transfer by radiation cannot occur across an absolute volume

The equipment used in the extraction of highly corrosive radioactive liquids is (A) Pulse column (B) Spray column (C) Mixer settler (D) Baffle tower

Description : The equipment used in the extraction of highly corrosive radioactive liquids is (A) Pulse column (B) Spray column (C) Mixer settler (D) Baffle tower

Last Answer : (A) Pulse column

Pumping of a corrosive liquid is generally preferred to be done by a __________ pump, as it can be made of a variety of materials including plastics. (A) Piston (B) Gear (C) Positive displacement (D) Sump

Description : Pumping of a corrosive liquid is generally preferred to be done by a __________ pump, as it can be made of a variety of materials including plastics. (A) Piston (B) Gear (C) Positive displacement (D) Sump

Last Answer : (B) Gear

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

Explain with reason through which side of shell and tube heat exchanges, the following liquids are directed. (i) viscous liquid (ii) high pressure liquid (iii) corrosive liquid

Description : Explain with reason through which side of shell and tube heat exchanges, the following liquids are directed. (i) viscous liquid (ii) high pressure liquid (iii) corrosive liquid

Last Answer : Viscous liquid : Viscous liquid is passed through shell side Reason: because of the presence of baffles in the shell induce turbulence and hence increases heat transfer rate. High pressure liquid: High ... To avoid expensive alloy shells (in order to save the cost of expensive material for shell).