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 : 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 : 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 : Power loss in an orificemeter is __________ that in a Venturimeter. (A) Less than (B) Same as (C) More than (D) Data insufficient, cannot be predicted
Last Answer : (C) More than
Description : The activity of an ideal gas is numerically __________ its pressure. (A) More than (B) Less than (C) Equal to (D) Data insufficient, can't be predicted
Last Answer : (C) Equal to
Description : Reynolds number for water flow through a tube of I.D. 5 cm is 1500. If a liquid of 5 centipoise viscosity and 0.8 specific gravity flows in the same pipe at the same velocity, then the pressure drop will (A) Increase (B) Decrease (C) Remain same (D) Data insufficient to predict pressure drop
Last Answer : (A) Increase
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
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 : 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)
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
Description : Two fluids are flowing through two similar pipes of the same diameter. The Reynold's number is same. For the same flow rate if the viscosity of a fluid is reduced to half the value of the ... (A) Increase (B) Decrease (C) Remain unchanged (D) Data insufficient to predict relative pressure drop
Last Answer : (B) Decrease
Description : Rate determining step in a reaction consisting of a number of steps inseries is the __________ step. (A) Fastest (B) Slowest (C) Intermediate (D) Data insufficient; can't be predicted
Last Answer : (B) Slowest
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
Description : In a first order reaction, the time required to reduce the concentration of reactant from 1 mole/litre to 0.5 mole/litre will be __________ that requiredto reduce it from 10 moles/litre to 5 moles/litre in the ... (A) More than (B) Less than (C) Same as (D) Data insufficient; can't be predicted
Last Answer : (C) Same as
Description : With the same reaction time, initial concentration and feed rate, the reaction 2A → B is carried out separately in CSTR and P.F. reactor of equal volumes. The conversion will be (A) Higher in P.F. reactor (B) Higher in CSTR (C) Same in both the reactors (D) Data insufficient; can't be predicted
Last Answer : (A) Higher in P.F. reactor
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
Description : With increase in the space time of an irreversible isothermal reaction being carried out in a P.F. reactor, the conversion will (A) Increase (B) Decrease (C) Remain same (D) Data in insufficient; can't be predicted
Description : . For the same feed, feed quality and separation (in a distillation column), with the increase of total pressure, the number of ideal plates will (A) Increase (B) Decrease (C) Remain same (D) Data insufficient, can't be predicted
Description : A fuel containing carbon and carbon monoxide (but containing no hydrogen or its compounds) is burnt in pure oxygen at constant pressure. Its gross calorific value as compared to net calorific value will be (A) More (B) Less (C) Same (D) Data insufficient; can't be predicted
Last Answer : (C) Same
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
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 : Sensible heat absorbed by 1 lb of water when it is heated from 32 to 212°F may be around __________ BTU. (A) 180 (B) 970 (C) 3.97 (D) Data insufficient, can't be predicted
Last Answer : (A) 180
Description : One kilogram of water at 0°C is changed to superheated steam of one atm pressure and 300° C. The major heat consumption in the process will be to (A) Heat the water from 0°C to 100°C (B) Evaporate the water (C) To superheat the steam (D) Data insufficient, can't be predicted
Last Answer : (B) Evaporate the water
Description : A chemical reaction, A → 3B, is conducted in a constant pressure vessel. Starting with pure A, the volume of the reaction mixture increases 3 times in 6 minutes. The fractional conversion is (A) 0.33 (B) 0.5 (C) 1 (D) Data insufficient, can't be predicted
Last Answer : (C) 1
Description : For an isothermal process, the internal energy of a gas (A) Increases (B) Decreases (C) Remains unchanged (D) Data insufficient, can't be predicted
Last Answer : (C) Remains unchanged
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 : 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 : A first order reaction requires two unequal sized CSTR. Which of thefollowing gives higher yield? (A) Large reactor followed by smaller one (B) Smaller reactor followed by larger one (C) Either of the arrangement (A) or (B) will give the same yield (D) Data insufficient, can't be predicted
Last Answer : (C) Either of the arrangement (A) or (B) will give the same yield
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
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
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
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
Description : The effect of changing the evaporator temperature on COP as compared to that of changing the condenser temperature (in vapour compression refrigeration system) is (A) Less pronounced (B) More pronounced (C) Equal (D) Data insufficient, can't be predicted
Last Answer : (B) More pronounced
Description : As the time is passing, entropy of the universe (A) Is increasing (B) Is decreasing (C) Remain constant (D) Data insufficient, can't be predicted
Last Answer : (A) Is increasing
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
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
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
Description : Compressibility factor (i.e., the ratio of actual volume of gas to the volume predicted by ideal gas law) for all gases are (A) Always greater than one (B) Same at the same reduced temperature (C) Same at the same reduced pressure (D) Both (B) & (C)
Last Answer : (D) Both (B) & (C)
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
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
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
Description : Pick out the wrong statement. (A) When the concentration difference for the mass transfer becomes zero at the bottom of the gas absorption tower, then the upper end of the operating line touches the ... fixed gas flow rate, the slope of the operating line decreases, in case of gas absorption process
Last Answer : (C) The operating line lies above the equilibrium curve in case of a gas desorber
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)
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
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 : 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 : A cylinder contains 640 gm of liquid oxygen. The volume occupied (in litres) by the oxygen, when it is released and brought to standard conditions (0°C, 760 mm Hg) will be __________ litres. (A) 448 (B) 224 (C) 22.4 (D) Data insufficient; can't be computed
Last Answer : (A) 448
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)
Description : In case of staged packed bed reactors carrying out exothermic reaction, use (A) High recycle for pure gas (B) Plug flow for dilute liquid requiring no large preheating of feed (C) Cold shot operations for a ... preheating to bring the stream upto the reaction temperature (D) All (A), (B) and (C)
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
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)