Fluidization Engineering

Pressure Drop in Fluidized Beds

Question 1
Marks : +2 | -2
Pass Ratio : 100%
What does the minimum fluidization velocity in the bed depends on?
Size distribution of solids
Pumping power
Diameter of bed
All of the mentioned
Explanation:
Solids size, power and diameter are considered while calculating the minimum fluidization velocity.
Question 2
Marks : +2 | -2
Pass Ratio : 100%
What happens if we continuously increase the velocity after attaining the constant pressure drop?
Remains constant
Pressure drop decreases to zero
Slight reduction in pressure drop
Slight increase in pressure drop
Explanation:
Increasing velocity further makes the particles lift off completely and hence the pressure drop reduces completely to zero.
Question 3
Marks : +2 | -2
Pass Ratio : 100%
During the increase of velocity of fluid in the bed, how does the graph of pressure drop follows?
Linear
Exponential
Non-linear
None of the mentioned
Explanation:
Till the velocity of gas balances the weight of the particles the growth is linear.
Question 4
Marks : +2 | -2
Pass Ratio : 100%
When does the initiation of entrainment start in the fluidized bed?
Before the pressure drop goes to zero
Point when pressure drop becomes constant
Start of the fluidization process
None of the mentioned
Explanation:
When the velocity goes high the particles start lifting up, it is the point when the entrainment has started.
Question 5
Marks : +2 | -2
Pass Ratio : 100%
What is one of the reason for poor fluidization beds in terms of pressure drop?
Slugging
Low velocity
Light particles
All of the mentioned
Explanation:
Slug formation leads to irregular distribution of pressure drop in the bed.
Question 6
Marks : +2 | -2
Pass Ratio : 100%
When the velocity of fluid is infinity, the pressure drop goes to zero, give example of its physical application?
Pneumatic conveyors
Dilution of solids
Transportation
All of the mentioned
Explanation:
Since the velocity of fluid is high, the particles are carried away and used for mostly transportation purpose.
Question 7
Marks : +2 | -2
Pass Ratio : 100%
How the gas behave across the fluidized bed, when the velocity is more than minimum fluidization?
Bubbles formation
Slugs formation
Smooth flow
None of the mentioned
Explanation:
Since we have voids formed, the gas try to form bubbles while passing through the bed.
Question 8
Marks : +2 | -2
Pass Ratio : 100%
Before the pressure drop stabilizes after the bed gets fluidized, what is the position of pressure drop before reaching minimum fluidization?
Above the constant
Below the constant
Equal
Hard to tell
Explanation:
Since it requires extra pressure during the particles are lifted in air.
Question 9
Marks : +2 | -2
Pass Ratio : 100%
In the packed bed, at relatively low flow rates pressure drop is approximately proportional to gas velocity, true or false?
True
False
Explanation:
From Umf expression, this relation has peen taken.
Question 10
Marks : +2 | -2
Pass Ratio : 100%
How the liquid behave across the fluidized bed, when the velocity is more than minimum fluidization?
Bubbles formation
Slugs formation
No bubbles
None of the mentioned
Explanation:
Since we have no voids formed, the liquid forms smooth flow in the bed.