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Multiple choice question for engineering

Set 1

1. For exothermic oxidation, which technology helps in better heat distribution in the reactor?
a) Fluidized bed
b) Spouted bed
c) Using air blowers in reactors
d) None of the mentioned

View Answer

Answer: a [Reason:] Due to continuous flow air and back mixing, heat is distributed uniformly.

2. What are the requirements of Dorr-Oliver Fluosolids roaster?
a) Less excess air
b) Higher capacity
c) Short circuiting
d) All of the mentioned

View Answer

Answer: d [Reason:] They are required to encounter various problems.

3. Why do the roaster require less excess air?
a) For better roasting of sulphur ores
b) To maintain required temperature
c) To give off gas
d) All of the mentioned

View Answer

Answer: c [Reason:] To give off gas with higher concentration of sulphur dioxide concentration.

4. What is the main problem occurring due to back mix flow of solids?
a) Short circuiting of solids
b) Distribution of heat is interrupted
c) Irregular roasting of sulphide ores
d) Irregular distribution of solids

View Answer

Answer: a [Reason:] Back mixing of solids leads to short circuiting in the single-stage unit.

5. When the bed is maintained at height of 1.2m to 1.5m, how much % of cinder is entrained?
a) 75 to 80
b) 10 to 15
c) 30 to 35
d) 55 to 60

View Answer

Answer: a [Reason:] Since there is no Transport disengaging height provided, its leading to more entrainment.

6. In order to maintain temperature in the bed, what is introduced in the bed to maintain the temperature?
a) Water spray
b) Cooling coil
c) Coolant spray
d) All of the mentioned

View Answer

Answer: d [Reason:] Any of the above methods can be used to remove heat from the bed.

7. What did BASF optimized in order to get particle growth and reduce roasting time?
a) High temperature
b) Low temperature
c) Faster gas velocity
d) Low gas velocity

View Answer

Answer: a [Reason:] High temperature along with shallow bed and large freeboard helps in particle growth.

8. How is copper or cobalt removed from sulphide ore?
a) Leaching
b) Filtration
c) Sieving
d) Froth floatation

View Answer

Answer: a [Reason:] Leaching with water or sulphuric acid, copper or cobalt is removed.

9. At what temperature of the feed slug is maintained(degree Celsius) ?
a) 500 to 600
b) 880 to 930
c) 750 to 780
d) 1050 to 1150

View Answer

Answer: b [Reason:] For maximum roasting of ore to take place.

10. How is the temperature of slug maintained in the reactor?
a) Water
b) Sulphuric acid
c) Steam
d) Ice vapour

View Answer

Answer: a [Reason:] By adding water to slurry, temperature is maintained.

Set 2

1. Which technology has been incorporated into production of cement clinker?
a) Fluidization
b) Pulverization
c) Cracking
d) None of the mentioned

View Answer

Answer: a [Reason:] Pyzel invented cement clinker by fluidization.

2. Pilot plant for cement clinker developed by Fuller company, had capacity of _________ tons clinker/day?
a) 20
b) 40
c) 70
d) 100

View Answer

Answer: c [Reason:] Pilot plant ranges from 65 to 85 tons clinker/day.

3. What are dimension of diameter used for reactor in the cement clinker (metre)?
a) 2.5
b) 5
c) 7.5
d) 10

View Answer

Answer: a [Reason:] In order to provide proper heat transfer and for better pelletization.

4. What are preheating processes installed in the plant?
a) Raw material pretreatment
b) Air pretreatment
c) Fuel gas pretreatment
d) All of the mentioned

View Answer

Answer: d [Reason:] For better formation of clinkers, raw material, air and fuel gas but be pretreated.

5. At what temperature is the bed maintained for cement clinkering to take place (degree Celsius)?
a) 100
b) 500
c) 1000
d) 1300

View Answer

Answer: d [Reason:] High temperature is required so that powder coats the clinker pellets.

6. How much heat is consumed in the single-stage operation(kcal/kg clinker)?
a) 500
b) 1100
c) 1500
d) None of the mentioned

View Answer

Answer: b [Reason:] Based on the energy balance study, it was found that heat consumption ranges from 1050 to 1180 kcal/kg clinker.

7. What are modes of heat loses in this process?
a) Hot gas
b) Hot product solid
c) Hot air
d) All of the mentioned

View Answer

Answer: d [Reason:] Heat is lost through hot gas, air and product solids.

8. How are the clinkers separated from the product mixture feed?
a) Filters
b) Sieves
c) Membrane
d) None of the mentioned

View Answer

Answer: b [Reason:] Since sieves are made of metal and have strong durability and can resist the frictional force by the cement without eroding it.

9. Which equipment is used to reduce the temperature of hot solid product?
a) Coolers
b) Blowers
c) Reduce temperature
d) None of the mentioned

View Answer

Answer: a [Reason:] Coolers reduce the temperature much faster compared to other modes.

10. Which gas is used for fluidizing the feed in the reactor?
a) Fuel gas
b) Steam
c) Air
d) All of the mentioned

View Answer

Answer: a [Reason:] For maintaining high temperature in order to proceed with the process.

Set 3

1. Multistage fluidized drier (below fig), was developed based on what purpose?
fluidization-engineering-questions-answers-drying-sizing-q1
a) To prevent bypassing of solids
b) To allow bypassing of solids
c) Widen the residence time distribution
d) None of the mentioned

View Answer

Answer: a [Reason:] It is main reason for decreasing efficiency in single stage drier.

2. What if the temperature is further increased more than 74 degrees mentioned in below fig?
fluidization-engineering-questions-answers-drying-sizing-q2
a) Better drying will take place
b) Might damage the solids, or will reach boiling point of solids
c) Will take time for drying
d) None of the mentioned

View Answer

Answer: b [Reason:] It depends on the material we use, since the temperature is already mentioned it would have been tested before applying it.

3. What kind of driers are used for drying limestone, dolomite,coal, plastics?
a) Fluosolids dryers
b) Multi-stage dryers
c) Two-staged fluidized dryers
d) None of the mentioned

View Answer

Answer: a [Reason:] Because it shows typical operating capabilities.

4. In two-stage dryer equipment, what is the temperature of the inlet gases on each stage from bottom?
a) 32 and 200 degrees
b) 200 and 32 degrees
c) 16 and 100 degrees
d) 100 and 16 degrees

View Answer

Answer: a [Reason:] Because it is decided from laboratory testing.

5. What is the maximum water content of the outlet limestone in fluosolids driers fluidized by combustion gas?
a) Zero
b) 0.1%
c) 1%
d) 1.5%

View Answer

Answer: a [Reason:] Based on the tabular content provided by Fluosolids driers.

6. What is the maximum water content of the outlet blast furnace slag in fluosolids driers fluidized by combustion gas?
a) 0.1-0.4%
b) 0.4-0.8%
c) 0.8-1.2%
d) 1.2-1.6%

View Answer

Answer: a [Reason:] Based on the tabular content provided by Fluosolids driers.

7. What is the temperature of bed in fluosolids driers fluidized by combustion gas for limestone?
a) 94-107 degrees
b) 150-200 degrees
c) 60-65 degrees
d) None of the mentioned

View Answer

Answer: a [Reason:] Based on the tabular content provided by Fluosolids driers.

8. What is the temperature of bed in fluosolids driers fluidized by combustion gas for blast furnace slag?
a) 94-105 degrees
b) 150-200 degrees
c) 60-65 degrees
d) None of the mentioned

View Answer

Answer: a [Reason:] Based on the tabular content provided by Fluosolids driers.

9. What is the temperature of bed in fluosolids driers fluidized by combustion gas for coal?
a) 94-105 degrees
b) 150-200 degrees
c) 60-65 degrees
d) None of the mentioned

View Answer

Answer: c [Reason:] Based on the tabular content provided by Fluosolids driers.

10. What is the maximum water content of coal in fluosolids driers fluidized by combustion gas?
a) 0.1-0.2%
b) Zero
c) 1-2%
d) None of the mentioned

View Answer

Answer: a [Reason:] Based on the tabular content provided by Fluosolids driers.

Set 4

1. From above figure, what is the diameter of particles with respect to ‘A'(Hint: Glass sphere)?
a) 0.051 mm
b) 0.074 mm
c) 0.094 mm
d) 0.162 mm

View Answer

Answer: a [Reason:] Smaller the particles size, early entrainment will take place.

2. From above figure, what is the diameter of particles with respect to ‘B'(Hint: Glass sphere)?
a) 0.051 mm
b) 0.074 mm
c) 0.094 mm
d) 0.162 mm

View Answer

Answer: b [Reason:] Medium particles size, at moderate time the entrainment will take place.

3. From above figure, what is the diameter of particles with respect to ‘C'(Hint: Glass sphere)?
a) 0.051 mm
b) 0.074 mm
c) 0.094 mm
d) 0.162 mm

View Answer

Answer: c [Reason:] Larger the particles size, lately the entrainment will take place.

4. From above figure, what is the diameter of particles with respect to ‘E'(Hint: Catalyst)?
a) 0.051 mm
b) 0.074 mm
c) 0.094 mm
d) 0.162 mm

View Answer

Answer: d [Reason:] Larger the particles size, lately entrainment will take place.

5. From above figure, how increase in pressure is affecting the velocity of solid particles?
a) Decreases
b) Increases
c) No change
d) Fluctuating

View Answer

Answer: a [Reason:] From experimental data provided.

6. From above figure, how decrease in pressure is affecting the velocity of solid particles?
a) Decreases
b) Increases
c) No change
d) Fluctuating

View Answer

Answer: b [Reason:] From experimental data provided.

7. Based on which property the solids get separated while elutrition?
a) Size
b) Shape
c) Density
d) All of the mentioned

View Answer

Answer: d [Reason:] Various factors are responsible for elutrition to take place.

8. How does the introduction of internals in the bed help in elutrition?
a) Separate big size particles
b) Separate small size particles
c) Breaks large particles
d) None of the mentioned

View Answer

Answer: c [Reason:] Prevents larger particles by forming an obstruction and breaking them.

9. For particles to not reach the TDH, what is the condition required?
a) Ut<Uo
b) Ut>Uo
c) Ut=Uo
d) Ut<=Uo

View Answer

Answer: b [Reason:] Velocity at which it just reaches the bottom of TDH.

10. Total entrainment rate= SUM(entrainment rate of particle size*fraction of that size in bed) , true or false?
a) True
b) False

View Answer

Answer: a [Reason:] Derived from theoretical knowledge and applying maths.

Set 5

1. When a salt solution is injected into a bed of dry particles fluidized by hot gas, the particles grow by?
a) Salt build-up
b) Sticking to each other
c) By collisions
d) None of the mentioned

View Answer

Answer: a [Reason:] Based on experiments conducted by Methany and Vance.

2. The particle growth proceeds by successive wetting with liquid feed followed by solidification through drying, true or false?
a) True
b) False

View Answer

Answer: a [Reason:] Based on experiments conducted by Methany and Vance.

3. How can the product size and size distribution are controlled in the bed of dry particles fluidized by hot gas?
a) By size of seed particles
b) By adjusting the liquid-to-solid feed ratio
c) The ratio of sprayed volume to volume of bed
d) All of the mentioned

View Answer

Answer: d [Reason:] Based on experiments conducted by Methany and Vance.

4. According to Ciborowski, after performing experiments on naphthalene, what was the decrease in efficiency percent when the gas velocity was increased?
a) 100% to 80-90%
b) 100% to 70-60%
c) 100% to 40-50%
d) None of the mentioned

View Answer

Answer: a [Reason:] Based on data from experiments conducted by Ciborowski.

5. According to Ciborowski, after performing experiments on naphthalene, when there is decrease in efficiency of condensation?
a) Increase in gas velocity
b) Increase in driving force
c) Increase in concentration
d) All of the mentioned

View Answer

Answer: d [Reason:] Based on data from experiments conducted by Ciborowski.

6. A continuous, fluid char adsorption process for separation and recovery of gaseous components was developed by?
a) Esso laboratories
b) Jyothi labs
c) Hetero drugs
d) Mylan laboratories

View Answer

Answer: a [Reason:] Esso laboratories developed the equipment.

7. How many bubble caps were fabricated inside the fluid char adsorption process for separation and recovery of gaseous components?
a) 20
b) 10
c) 5
d) 50

View Answer

Answer: a [Reason:] Based on the data produced from Esso laboratories.

8. What was the major problem faced by the process developed by Esso laboratories which prevented to use commercially?
a) Erosion during transportation and fluidization
b) Process was too costly
c) Equipment was very difficult to handle manually
d) None of the mentioned

View Answer

Answer: a [Reason:] Such operations should be careful about breakage and erosion during transportation and fluidization.

9. What is the percentage of CS2 adsorbed from Rowson recovery plant?
a) 90-95%
b) 10-15%
c) 50-75%
d) 100%

View Answer

Answer: a [Reason:] According to data provided by Rowson experiments.

10. How much was the fan HP required for five-stage fluidized absorber developed by Rowson?
a) 1000 hp
b) 500 hp
c) 250 hp
d) 100 hp

View Answer

Answer: a [Reason:] According to data provided by Rowson experiments.