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

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
by

1 Answer

Answer :

(C) Decreases pressure drop, increases surface area
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

The most common packing used in industrial operations is __________ rings. (A) Raschig (B) Lessing (C) Cross-partition (D) Single spiral

Description : The most common packing used in industrial operations is __________ rings. (A) Raschig (B) Lessing (C) Cross-partition (D) Single spiral

Last Answer : (C) Cross-partition

Which of the following ceramic packing materials is the costliest of all? (A) Berl saddles (B) Raschig rings (C) Pall rings (D) Intalox saddles

Description : Which of the following ceramic packing materials is the costliest of all? (A) Berl saddles (B) Raschig rings (C) Pall rings (D) Intalox saddles

Last Answer : Berl saddles

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

Pick out the correct statement. (A) Fanning friction factor is inversely proportional to Reynolds number always (B) The property of a randomly packed bed (with raschig rings) is given by the ratio of the total volume to the volume of voids in the bed (C) Mach number in an incompressible fluid is always unity (D) Mach number is given by the ratio of the speed of the fluid to that of sound in the fluid under conditions of flow

Description : Pick out the correct statement. (A) Fanning friction factor is inversely proportional to Reynolds number always (B) The property of a randomly packed bed (with raschig rings) is given by the ratio of the ... the ratio of the speed of the fluid to that of sound in the fluid under conditions of flow

Last Answer : (D) Mach number is given by the ratio of the speed of the fluid to that of sound in the fluid under conditions of flow

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

Sphericity is the ratio of the surface area of a spherical particle having the same volume as the particle to the surface area of the particle. Which of the following has the maximum value of sphericity? (A) Sphere(B) Cube(C) Cylinder (L/D = 1)(D) Raschig rings

Description : Sphericity is the ratio of the surface area of a spherical particle having the same volume as the particle to the surface area of the particle. Which of the following has the maximum value of sphericity? (A) Sphere (B) Cube (C) Cylinder (L/D = 1) (D) Raschig rings

Last Answer : (A) Sphere

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 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)

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)

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

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

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

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

For raschig rings, the sphericity is (A) 0.5 (B) 1 (C) < 1

Description : For raschig rings, the sphericity is (A) 0.5 (B) 1 (C) < 1

Last Answer : (C) < 1

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

(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

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

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

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 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)

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 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

For the same heat load and mass flow rate in the tube side of a shell and tube heat exchanger, one may use multipass on the tube side, because it (A) Decreases the pressure drop (B) Decreases the outlet temperature of cooling medium (C) Increases the overall heat transfer coefficient (D) None of these

Description : For the same heat load and mass flow rate in the tube side of a shell and tube heat exchanger, one may use multipass on the tube side, because it (A) Decreases the pressure drop (B) ... the outlet temperature of cooling medium (C) Increases the overall heat transfer coefficient (D) None of these

Last Answer : (C) Increases the overall heat transfer coefficient

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)

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

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

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

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

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

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

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

With increase in the pressure drop across the cake, the specific cake resistance for the compressible sludge (A) Increases (B) Decreases (C) Remains constant (D) Increases linearly

Description : With increase in the pressure drop across the cake, the specific cake resistance for the compressible sludge (A) Increases (B) Decreases (C) Remains constant (D) Increases linearly

Last Answer : (A) Increases

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

Rittinger's number designates the new surface created per unit mechanical energy absorbed by the material being crushed. Larger value of Rittinger's number of a material indicates its (A) Easier grindability (B) Poor grindability (C) High power consumption in grinding (D) None of these

Description : Rittinger's number designates the new surface created per unit mechanical energy absorbed by the material being crushed. Larger value of Rittinger's number of a material indicates its (A) Easier grindability (B) Poor grindability (C) High power consumption in grinding (D) None of these

Last Answer : (A) Easier grindability

Rittinger number which designates the new surface produced per unit of mechanical energy absorbed by the material being crushed, depends on the (A) State or manner of application of the crushing force (B) Ultimate strength of the material (C) Elastic constant of the material (D) All (A), (B) and (C)

Description : Rittinger number which designates the new surface produced per unit of mechanical energy absorbed by the material being crushed, depends on the (A) State or manner of application of the crushing force (B) Ultimate strength of the material (C) Elastic constant of the material (D) All (A), (B) and (C)

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

Maximum permissible velocity 1.5 m/sec, is adopted in drains A. With beds of rocks and gravels B. Lined with stones C. Both A. and B. D. Neither A. nor B.

Description : Maximum permissible velocity 1.5 m/sec, is adopted in drains A. With beds of rocks and gravels B. Lined with stones C. Both A. and B. D. Neither A. nor B.

Last Answer : ANS: C

Pick up the correct statement from the following: (A) In stone arches, the stones are placed with their natural beds radial (B) In cornices, the stones are placed with their natural beds as vertical (C) In stone walls, the stones are placed with their natural beds as horizontal (D) All the above

Description : Pick up the correct statement from the following: (A) In stone arches, the stones are placed with their natural beds radial (B) In cornices, the stones are placed with their natural beds as vertical (C) In stone walls, the stones are placed with their natural beds as horizontal (D) All the above

Last Answer : Answer: Option D

What happens when a drop of glycerol is added to crushed KMnO4 spread on a paper? (1) There is a crackling sound (2) There is a violent explosion (3) There is no reaction (4) The paper ignites

Description : What happens when a drop of glycerol is added to crushed KMnO4 spread on a paper? (1) There is a crackling sound (2) There is a violent explosion (3) There is no reaction (4) The paper ignites

Last Answer : (2) There is a violent explosion Explanation: When solid Potassium Permanganate (KMnO4) is mixed with pure glycerol or other simple alcohols, it will result in a violent combustion ... Permanganate is an extremely powerful oxidizer which spontaneously ignites after coming in contact with glycerol.

What happens when a drop of glycerol is added to crushed KMnO4 spread on a paper ? (1) There is a crackling sound. (2) There is a violent explosion. (3) There is no reaction. (4) The paper ignites.

Description : What happens when a drop of glycerol is added to crushed KMnO4 spread on a paper ? (1) There is a crackling sound. (2) There is a violent explosion. (3) There is no reaction. (4) The paper ignites.

Last Answer : There is a violent explosion.

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 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

Sphericity of raschig ring (whose length and diameter are equal) is (A) > 1 (B) < 1 (C) 1 (D) 2

Description : Sphericity of raschig ring (whose length and diameter are equal) is (A) > 1 (B) < 1 (C) 1 (D) 2

Last Answer : (C) 1

Diameter to height ratio for a raschig ring is (A) 1 (B) 0.5 (C) 2 (D) 8

Description : Diameter to height ratio for a raschig ring is (A) 1 (B) 0.5 (C) 2 (D) 8

Last Answer : (A) 1

Raschig ring made of porcelain cannot be used for treating concentrated (A) Hydrochloric acid (B) Nitric acid (C) Alkalis (D) Sulphuric acid

Description : Raschig ring made of porcelain cannot be used for treating concentrated (A) Hydrochloric acid (B) Nitric acid (C) Alkalis (D) Sulphuric acid

Last Answer : (C) Alkalis

In area meter (e.g., Rotameter), with increase in the fluid flow rate, the (A) Pressure drop increases linearly (B) Pressure drop is almost constant (C) Area through which fluid flows does not vary (D) None of these

Description : In area meter (e.g., Rotameter), with increase in the fluid flow rate, the (A) Pressure drop increases linearly (B) Pressure drop is almost constant (C) Area through which fluid flows does not vary (D) None of these

Last Answer : (B) Pressure drop is almost constant

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