If the path of liquid across the plate is very long as in case of large

diameter tower, Murphree efficiency can be __________ percent

(A) 100

(B) > 100

(C) < 100

(D) None of these

1 Answer

Answer :

(B) > 100


Related questions

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

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

Description : When the liquid over a plate is of uniform concentration, then (A) Murphree efficiency > point efficiency (B) Murphree efficiency < point efficiency (C) Murphree efficiency = point efficiency (D) Murphree efficiency ≠ point efficiency

Last Answer : (C) Murphree efficiency = point efficiency

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

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

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

Description : The ratio of Murphree plate efficiency to point efficiency is always > 1 in a __________ flow model. (A) Plug (B) Perfectly mixed (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (A) Plug

Description : The ratio of Murphree plate efficiency to point efficiency is 1 in a __________ flow model. (A) Plug (B) Perfectly mixed (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (B) Perfectly mixed

Description : If the overall efficiency and Murphree plate efficiency are equal, then both the equilibrium and operating lines are: (A) Straight (B) Parallel (C) Both (A) & (B) (D) Neither (A) nor (B)

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

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

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)

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

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

Description : The reciprocal of stripping factor is termed as (A) Selectivity index (B) Relative volatility (C) Absorption factor (D) Murphree efficiency

Last Answer : (C) Absorption factor

Description : The expression, y(1 - x)/x(1 - y) is for (A) Absorption factor (B) Relative volatility (C) Selectivity (D) Murphree efficiency

Last Answer : (B) Relative volatility

Description : The efficiency of a plate column will be maximum, when the flow is ideal __________ the plate. (A) Across (B) Above (C) Both (A) & (B)

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

Description : The expected efficiency of a single riveted lap joint is of the order of 50%. If the thickness of the plate is increased four times, then the rivet diameter will have to be increased __________ times. (A) Two (B) Four (C) Six (D) Eight

Last Answer : Option A

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

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

Description : A natural draft cooling tower is filled with wooden grids, which covers about __________ percent of the tower height. (A) 10-15 (B) 30-40 (C) 70-80 (D) 90-100

Last Answer : (A) 10-15

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

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

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

Description : Tower diameter may be decreased by (A) Using higher reflux ratio (B) Use of increased tray spacing (C) Increasing the liquid flow rate (D) Increasing the vapour flow rate

Last Answer : (B) Use of increased tray spacing

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

Description : To get high tray efficiency (A) Interfacial surface between liquid and gas phase should be large (B) Time of contact between the two phases should be less (C) Gas velocity should be very low (D) Liquid entrainment should be severe

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

Description : In the early 1900's in England, there was two towns: town A and town B, and there was a huge river in between them. The only way across to each town was by a long bridge with a guard ... back. Many people have tried to cross but have always been caught, even very fast runners have only ab -Riddles

Last Answer : Did you get it? The answer is that they went up close to the guards tower, turned around and started walking back to the town they came from, the guard caught them and assumed that they came ... way and sent them back! Hope you enjoyed this, please subscribe and check back soon for more riddles!

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

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

Description : If b is the width of a plate joined by diamond riveting of diameter d, the efficiency of the joint is  given by  (A) (b + d)/b (B) (b - d)/b (C) (d - b)/d (D) (b - d)/d

Last Answer : (B) (b - d)/b

Description : For removal of very small amounts of precipitate from large volume of water, the most suitable filter is the __________ filter. (A) Plate & frame (B) Shell & lea (C) Sand (D) Rotary vacuum

Last Answer : (C) Sand

Description : The most suitable filter for the removal of very small amount of precipitate from very large volumes of water is the __________ filter. (A) Vacuum (B) Sand (C) Plate & frame (D) Rotary

Last Answer : (B) Sand

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

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

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

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

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

Description : Diameter of the rivet to be provided on a 20 mm. thick boiler plate will be __________ mm. (A) 10 (B) 20 (C) 30 (D) 40

Last Answer : (D) 40

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

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)

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

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

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

Description : Net efficiency of ordinary light water cooled nuclear reactor is about __________ percent. (A) 32 (B) 52 (C) 72 (D) 88

Last Answer : (A) 32

Description : Crushing efficiency of a machine ranges between __________ percent. (A) 0.1 to 2 (B) 5 to 10 (C) 20 to 25

Last Answer : (A) 0.1 to 2

Description : Grinding efficiency of a ball mill is of the order of __________ percent. (A) 1-5 (B) 40-50 (C) 75-80 (D) 90-95

Last Answer : (A) 1-5

Description : The thermal efficiency of a steel slab reheating furnace (walking beam type) may be about __________ percent. (A) 15 (B) 40 (C) 70 (D) 85

Last Answer : (B) 40

Description : Thermal efficiency of a limestone calcination rotary kiln may be around __________ percent. (A) 20 (B) 40 (C) 65 (D) 80

Last Answer : (B) 40

Description : Maximum thermal efficiency of boiler may be about __________ percent. (A) 10 (B) 25 (C) 65 (D) 90

Last Answer : (D) 90

Description : Thermal efficiency of blast furnace stoves used for heating blast (air) may be about __________ percent. (A) 20 (B) 40 (C) 60 (D) 80

Last Answer : (D) 80

Description : Thermal efficiency of an open hearth furnace may be about __________ percent. (A) 5 (B) 20 (C) 50 (D) 80

Last Answer : (B) 20

Description : Overall thermal efficiency of a lumpy coal fired suitably designed heating furnace, if operated & maintained properly may be about __________ percent. (A) 10-15 (B) 25-30 (C) 45-50 (D) 65-70

Last Answer : (B) 25-30