Fluidization Engineering Questions and Answers Part-1

1. What is the most important factor to be considered for designing a fluidized bed reactor?
a) Diameter of reactor
b) Height of reactor
c) Size distribution of solids
d) Gas flow rate

Answer: c
Explanation: Because for other factors to workout, solids properties are initially considered.

2. What is the best combination of fluidized bed for fluid catalytic cracking?
a) Spouted and teeter bed
b) Teeter and one pass for solids bed
c) Batch type and spouted bed
d) Batch type and circulation bed

Answer: d
Explanation: Because it requires regeneration of catalyst.

3. What is the maximum range of superficial gas velocity when the TDH of the bed is 0.25m to prevent eluitrition in a circular type fluidized bed reactor?
a) 0.1-5 m/sec
b) 1.5-12 m/sec
c) 12-24 m/sec
d) 5-5.5 m/sec

Answer: a
Explanation: The above range fits the design criteria for fluidized bed.

4. What is the advantage of fluidized bed over spouted bed and teeter bed in the drying process?
a) Presence of distributor
b) Reactor sizes
c) Presence of cyclone separators
d) None of the mentioned

Answer: a
Explanation: Distributor provides better distribution of inlet gas for covering the whole bed.

5. In case of naphtha cracking, use of batch type is better than circulation type fluidized bed?
a) true
b) false

Answer: b
Explanation: The presence of oil vapour for circulation is required only possible in circulation type.

6. There is a missing part in the fluidized bed construction shown in figure.1, state the required equipment and if any replacement for that part and possible explanation?
a) Cyclone separators and if possible filter bags
b) Diagram is not missing any part
c) Pressure gauge and if possible vacuum pump
d) Thermostat only

Answer: a
Explanation: Cyclone separators required for recycling the fine dust and it can be replaced with filter bags.

7. In a fluidized bed reactor, for a specific gas flow rate, any kind of Geldart type particles can be used. True of False?
a) true
b) false

Answer: b
Explanation: Since the ranges of the particles varies, there should be different gas flow rates.

8. In pneumatic transport, explain the importance of the classification of solids before its application has been started?
a) Any kind of solids range can be transported
b) Only Geldart ‘A’ and ‘B’ particles can be transported
c) Only Geldart ‘C’ and ‘D’ particles can be transported
d) Only Geldart ‘A’ and ‘D’ particles can be transported

Answer: b
Explanation: Sizes of solids matter, only small size particles which come under ‘A’ and ‘B’ Geldart type can be used. In fact, other types have to processed to ‘A’ and ‘B’ for pneumatic transport.

9. What is the mesh range of particles required in the fluidized bed for best efficiency?
a) 1-10 mesh
b) 5-50 mesh
c) 50-100 mesh
d) 20-200 mesh

Answer: d
Explanation: More the mesh number better is its fluidizing property.

10. In a fluidized bed reactor, what is the best way to achieve maximum heat and mass transfer rates?
a) Using small particles
b) Using large particles
c) Simply dumping the particle and passing gas will do the job
d) Increasing the gas flow rates

Answer: a
Explanation: More small particles more the surface area hence better transfer rates