# Fluidization Engineering Questions and Answers – Pressure Drop in Fluidized Beds

This set of Fluidization Engineering online quiz focuses on “Pressure Drop in Fluidized Beds”.

1. In the packed bed, at relatively low flow rates pressure drop is approximately proportional to gas velocity, true or false?
a) True
b) False

Explanation: From Umf expression, this relation has peen taken.

2. Before the pressure drop stabilizes after the bed gets fluidized, what is the position of pressure drop before reaching minimum fluidization?
a) Above the constant
b) Below the constant
c) Equal
d) Hard to tell

Explanation: Since it requires extra pressure during the particles are lifted in air.

3. How the gas behave across the fluidized bed, when the velocity is more than minimum fluidization?
a) Bubbles formation
b) Slugs formation
c) Smooth flow
d) None of the mentioned

Explanation: Since we have voids formed, the gas try to form bubbles while passing through the bed.

4. How the liquid behave across the fluidized bed, when the velocity is more than minimum fluidization?
a) Bubbles formation
b) Slugs formation
c) No bubbles
d) None of the mentioned

Explanation: Since we have no voids formed, the liquid forms smooth flow in the bed.

5. What happens if we continuously increase the velocity after attaining the constant pressure drop?
a) Remains constant
b) Pressure drop decreases to zero
c) Slight reduction in pressure drop
d) Slight increase in pressure drop

Explanation: Increasing velocity further makes the particles lift off completely and hence the pressure drop reduces completely to zero.

6. When the velocity of fluid is infinity, the pressure drop goes to zero, give example of its physical application?
a) Pneumatic conveyors
b) Dilution of solids
c) Transportation
d) All of the mentioned

Explanation: Since the velocity of fluid is high, the particles are carried away and used for mostly transportation purpose.

7. During the increase of velocity of fluid in the bed, how does the graph of pressure drop follows?
a) Linear
b) Exponential
c) Non-linear
d) None of the mentioned

Explanation: Till the velocity of gas balances the weight of the particles the growth is linear.

8. When does the initiation of entrainment start in the fluidized bed?
a) Before the pressure drop goes to zero
b) Point when pressure drop becomes constant
c) Start of the fluidization process
d) None of the mentioned

Explanation: When the velocity goes high the particles start lifting up, it is the point when the entrainment has started.

9. What is one of the reason for poor fluidization beds in terms of pressure drop?
a) Slugging
b) Low velocity
c) Light particles
d) All of the mentioned

Explanation: Slug formation leads to irregular distribution of pressure drop in the bed.

10. What does the minimum fluidization velocity in the bed depends on?
a) Size distribution of solids
b) Pumping power
c) Diameter of bed
d) All of the mentioned

Explanation: Solids size, power and diameter are considered while calculating the minimum fluidization velocity.

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