Slugging in a fluidised bed can be avoided by using (A) Tall narrow vessel (B) Deep bed of solids (C) Shallow beds of solids and proper choice of particle size (D) Very large particles

Slugging in a fluidised bed can be avoided by using
(A) Tall narrow vessel
(B) Deep bed of solids
(C) Shallow beds of solids and proper choice of particle size
(D) Very large particles
by

1 Answer

Answer :

(C) Shallow beds of solids and proper choice of particle size
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Related questions

Slugging occurs in a fluidised bed, if the bed is (A) Narrow (B) Deep (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : Slugging occurs in a fluidised bed, if the bed is (A) Narrow (B) Deep (C) Both (A) & (B) (D) Neither (A) nor (B)

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

A bed of spherical particles (specific gravity 2.5) of uniform size 1500 μm is 0.5 m in diameter and 0.5 m high. In packed bed state, the porosity may be taken as 0.4. Ergun's equation for the above fluid-particle system (in SI units) is given below: Δ P/L = 375 × 10 3 VOM + 10.94 × 10 6 V2 OM (SI units) If water is to be used as the fluidising medium, in actual operation, the above bed has a height = 1 m. What is the porosity of the fluidised bed? (A) 0.2 (B) 0.5 (C) 0.7 (D) 0.8

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Last Answer : (C) 0.7

In a fluidised bed reactor (A) Temperature gradients are very high (B) Temperature is more or less uniform (C) Hot spots are formed (D) Segregation of the solids occurs

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The uniformity of a gas fluidised bed depends upon the __________ of the solid particles. (A) Size (B) Surface properties (C) Both (A) and (B) (D) Neither (A) nor (B)

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Poundstretcher stores are characterised by a product assortment that is A)wide and deep B)wide and shallow. C)narrow and deep. D)narrow and shallow.

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Last Answer : B)wide and shallow.

Tie Rack stores are characterised by a product assortment that is: A)wide and deep B)wide and shallow. C)narrow and deep.D)narrow and shallow.

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Last Answer : C)narrow and deep

A limited -line wholesaler would be expected to carry a __________ product mix. A)wide and deep B)wide and shallow C)narrow and shallow D)wide E)narrow and deep

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Bed pressure drop in an air fluidised bed of catalyst particles (ρp = 200 kg/m3, Dp = 0.05 cm) of 60 cm bed depth and bed porosity of 0.5 expressed in cm of water (manometer) is (A) 90 (B) 60 (C) 45 (D) 30

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Last Answer : (B) 60

Bond crushing law (A) Calls for relatively less energy for the smaller product particles, than does the Rittinger law (B) Is less realistic in estimating the power requirements of commercial crushers (C) States that the work required to form particle of any size from very large feed is proportional to the square root of the volume to surface ratio of the product (D) States that the work required for the crushing is proportional to the new surface created

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With decrease in particle size to be fluidised by a particular fluid, the operating range of fluidisation velocity (A) Widens (B) Squeezes (C) Does not change (D) Unpredictable from the data

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Last Answer : (C) Does not change

The main factor on which the behaviour of a mass of fluidised solid depends mainly is the (A) Fluid characteristics (B) Particle size (C) Both (A) and (B) (D) Neither (A) nor (B)

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

A bed of spherical particles (specific gravity 2.5) of uniform size 1500 μm is 0.5 m in diameter and 0.5 m high. In packed bed state, the porosity may be taken as 0.4. Ergun's equation for the above fluid-particle system (in SI units) is given below : Δ P/L = 375 × 10 3 VOM + 10.94 × 10 6 V2 OM (SI units) If water is to be used as the fluidising medium, the minimum fluidisation velocity, VOM is (A) 12 mm/s (B) 16 mm/s (C) 24 mm/s (D) 28 mm/s

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Last Answer : (B) 16 mm/s

Fluidised beds are formed, when the (A) Fluid friction is zero (B) Gravity force is less than the fluid friction (C) Pressure forces equal gravity forces (D) Sum of the fluid friction and pressure forces is equal and opposite to gravity forces

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Pick up the incorrect statement from the following: (A) The function of foundation is to distribute the load of super structure over a large bearing area (B) No timbering is required for shallow trenches (C) Shallow foundations can be constructed on made-up soil (D) Black cotton soil is very good for foundation bed

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Large scale drying of wheat is done in a __________ dryer. (A) Fluidised bed (B) Spouted bed (C) Tray (D) Vacuum rotary

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I always run, I never walk;I have a mouth, I never talk;I have a bed, I never sleep;I can be shallow,I can be deep.What am I? -Riddles

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Which of the following is the most suitable for very high pressure gas phase reaction? (A) Batch reactor (B) Tubular flow reactor (C) Stirred tank reactor (D) Fluidised bed reactor

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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

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Which of the following factors control the design of a fluid-solid reactor? (A) Reaction kinetics for single particle (B) Size distribution of solids being treated (C) Flow patterns of solids and fluid in the reactor (D) All (A), (B) and (C)

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Which of the following is not a characteristic of Peninsular rivers? (a) Seasonal flow (b) Meandering tendency often shifting their beds (c) Flow through shallow valleys (d) Little erosional activity

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Last Answer : (C) 18 kWh/ton

Which is better for navigating shallow, narrow streams: a canoe or a kayak?

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Last Answer : answer:Canoes tend to be a bit more flat-bottomed. While you may think that'd help in shallow water it actually doesn't. In order to control a canoe with any real degree of directional ... carry stuff are limited to about a couple of small backpacks while a canoe can carry considerably more.

You have been referred a case of open angle glaucoma. Which of the following would be an important point in diagnosing the case? a. Shallow anterior chamber b. Optic disc cupping c. Narrow angle d. visual acuity and refractive error

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. Which of the following is used as a catalyst in fluidised bed catalytic cracking? (A) Silica-magnesia (B) Silica-alumina (C) Bentonite clays (D) All (A), (B) and (C

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. The most widely used crude topping column in refineries is the__________ column.(A) Bubble-cap(B) Packed bed(C) Fluidised bed(D) Perforated plate

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Thermofor catalytic cracking process is a __________ process. (A) Fixed bed (B) Moving bed (C) Fluidised bed (D) Non-catalytic

Description : Thermofor catalytic cracking process is a __________ process. (A) Fixed bed (B) Moving bed (C) Fluidised bed (D) Non-catalytic

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Platforming is a __________ process. (A) Moving bed (B) Fluidised bed (C) Non-regenerative & fixed bed (D) Regenerative

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Which of the following is the most widely used cracking process in oil refineries? (A) Dubbs process (B) T.C.C. moving bed process (C) Fluidised bed catalytic cracking process (D) Houdry's fixed bed process

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Sticky material can be dried in a __________ dryer. (A) Tray (B) Rotary (C) Fluidised bed (D) None of these

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Sand is dried in foundries in a _________drier. (A) Rotary (B) Fluidised bed (C) Vacuum (D) Spray

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Which of the following is not a batch drier? (A) Truck drier (B) Agitated pan drier (C) Fluidised bed drier (D) Vacuum shelf drier

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Description : Paper industry employs __________ driers. (A) Cylinder (B) Rotary (C) Spray (D) Fluidised bed

Last Answer : (A) Cylinder

Which of the following is not applicable to fluidised bed combustion of coal? (A) It cannot burn low grade coal (B) It achieves higher fuel combustion efficiency (C) Less heat transfer surface area is required in boilers (D) None of these

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Kopper-Totzek coal gasifier (installed in a coal based nitrogeneous fertiliser plant) employs a/an __________ bed gasifier. (A) Entrained (B) Moving (C) Fixed (D) Fluidised

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Lurgi coal gasifier is a pressurised __________ bed reactor. (A) Moving (B) Fixed (C) Fluidised (D) Entrained

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

. A 0.5 m high bed made up of a 1 mm dia glass sphere (density 2500 kg/m3 ) is to be fluidised by water (density 1000 kg/m3 ). If at the point of incipient fluidisation, the bed voidage is 40%, the pressure drop across the bed is (A) 4.4 KPa (B) 2.94 KPa (C) 3.7 KPa (D) None of these

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Last Answer : (A) 4.4 KPa

Minimum porosity for fluidisation is(A) That corresponding to static bed (B) That corresponding to completely fluidised bed (C) The porosity of the bed when true fluidisation begins (D) Less than that of the' static bed

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Last Answer : (C) The porosity of the bed when true fluidisation begins

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

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Last Answer : (B) Bubbling bed

For high conversion in a highly exothermic solid catalysed reaction, use a __________ bed reactor. (A) Fixed (B) Fluidised bed reactor followed by a fixed (C) Fixed bed reactor followed by a fluidised (D) Fluidised

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Last Answer : (B) Fluidised bed reactor followed by a fixed

Which of the following will give maximum gas conversion? (A) Fixed bed reactor (B) Fluidised bed reactor (C) Semi-fluidised bed reactor (D) Plug-flow catalytic reactor

Description : Which of the following will give maximum gas conversion? (A) Fixed bed reactor (B) Fluidised bed reactor (C) Semi-fluidised bed reactor (D) Plug-flow catalytic reactor

Last Answer : (C) Semi-fluidised bed reactor

Which of the following is used for calcination of limestone and dolomite in industrial practice? (A) Fluidised bed reactor (B) Moving bed reactor (C) Fixed bed reactor (D) None of these

Description : Which of the following is used for calcination of limestone and dolomite in industrial practice? (A) Fluidised bed reactor (B) Moving bed reactor (C) Fixed bed reactor (D) None of these

Last Answer : (B) Moving bed reactor

Commercial scale production of hydrogen from iron-steam reaction represented by, 3Fe + 3H2O = Fe3O4 + 4H2 , is not practised, as it is (A) A slow reaction (B) A discontinuous reaction (requiring regeneration of iron by water gas intermittently) (C) Still in development stage (by employing fluidised bed technique) (D) All (A), (B) and (C)

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. Lurgi coal gasifier is a pressurised __________ bed reactor. (A) Moving (B) Fixed (C) Fluidised (D) Entrained

Description : . Lurgi coal gasifier is a pressurised __________ bed reactor. (A) Moving (B) Fixed (C) Fluidised (D) Entrained

Last Answer : (A) Moving

Calcination of limestone is not done in a __________ kiln for producing lime. (A) Vertical shaft (B) Rotary (C) Fluidised bed (D) Fixed bed

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Last Answer : (D) Fixed bed

Heat transfer by __________ is almost absent in case of fluidised bed drying operation. (A) Radiation (B) Conduction (C) Convection (D) Both (B) & (C)

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