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Multiple choice question for engineering

Set 1

1. In fluid catalytic cracking(FCC) process, how does the heavy hydrocarbon crack into lower molecular compounds?
a) On contact with catalyst
b) By heating at high temperature
c) By pyrolysis process
d) None of the mentioned

View Answer

Answer: a [Reason:] Heavy hydrocarbons crack when they come in contact with catalyst.

2. In fluid catalytic cracking process, cracking of heavy hydrocarbons into lower hydrocarbons, is an endothermic process, true of false?
a) True
b) False

View Answer

Answer: a [Reason:] Since cracking utilizes more energy for cracking heavy hydrocarbons.

3. After the process, the catalyst gets deactivated, how it can ge regenerated?
a) Burning off the carbon in air
b) Replacing the catalyst
c) Using brine solution
d) Using Sulphuric acid

View Answer

Answer: a [Reason:] Carbon which gets adsorbed on the catalyst has to be burnt off.

4. What are the two sections of the fluid catalytic cracking process?
a) Reactor and Regenerator
b) Plug flow reactor and tubular reactor
c) Batch reactor and tubular reactor
d) Batch reactor and heat exchanger

View Answer

Answer: a [Reason:] Reactor is used for cracking process and regenerator for regeneration of catalyst.

5. How is the circulation regulated between the reactor and regenerator in FCC?
a) Plug valves
b) Slide valves
c) Gate valves
d) Piston valves

View Answer

Answer: a [Reason:] Undergoes less erosion than other valves.

6. How are the no. of holes decided on the distributor, in the fluid catalytic cracking unit?
a) Pressure drop
b) Height of bed
c) Superficial velocity of gas
d) None of the mentioned

View Answer

Answer: a [Reason:] Pressure drop should be about 35 to 70 cm water, depending on that no. of holes are decided.

7. How can we prevent the flat distributor to buckle off under normal stresses, in FCC?
a) Concave plates
b) Convex plates
c) Both concave and convex plates
d) None of the mentioned

View Answer

Answer: c [Reason:] Using both plates will withstand more stresses than individual.

8. What are problems encountered in the fluid catalytic cracking unit?
a) Violent bubbling action
b) Gas by-passing
c) More load on gas cleaning equipments
d) All of the mentioned

View Answer

Answer: d [Reason:] FCC units facing all these problems because of poor flow pattern which leads to above consequences.

9. How can we study and control the size distribution factors which are responsible for improved circulations in FCC?
a) Attrition kinetics and cyclone effectiveness
b) Flow patterns of bubbles
c) Kinetics of catalyst in the regenerator
d) None of the mentioned

View Answer

Answer: a [Reason:] Knowledge on attrition kinetics and cyclone effectiveness helps to manipulate these factors to proper advantage.

10. How did Shell oil company managed to reduce serious gas bypassing in FCC unit?
a) Using plug flow and fluidized bed
b) Reactor and Regenerator
c) Plug flow reactor and tubular reactor
d) Batch reactor and fluidized bed

View Answer

Answer: a [Reason:] First stage with plug flow and second stage with fluidized bed have help to reduce gas bypassing.

Set 2

fluidization-engineering-questions-answers-fluid-coking-q1
1. Based on the above diagram, what is present just about the reactor in the fluid coking unit?
a) Heater
b) Condenser
c) Slurry recycle
d) None of the mentioned

View Answer

Answer: c [Reason:] It is implied to collect the dust impurities as slurry.

2. What is the percentage of coke obtained from the fluid coking unit?
a) 53-60%
b) 67-79%
c) 88-93%
d) 93-100%

View Answer

Answer: c [Reason:] Based on the experimental data it was found that the coking unit can get upto 93% of coke product.

3. What is the side product formed along with coke products?
a) Gas oil
b) Water
c) Carbon dioxide
d) All of the mentioned

View Answer

Answer: a [Reason:] The equipment was developed to produce coke as well as gas oil.

4. What is the particle size of the coke formed in the product?
a) 20 mesh
b) 50 mesh
c) 100 mesh
d) All of the mentioned

View Answer

Answer: d [Reason:] All the meshes come in the range of the product particle sizes.

5. Why is the fractionator present on the top of the reactor?
a) Separate gas oil
b) Separate dust particles
c) Separate oil particles
d) None of the mentioned

View Answer

Answer: a [Reason:] The un-condensed gas oil is separated from other impurities and sent to other condenser.

6. What if we don’t have a slurry recycler on top of the reactor in coking unit?
a) Hard to separate gas oil
b) More easy to separate gas oil
c) Helps in the condensing gas oil
d) None of the mentioned

View Answer

Answer: a [Reason:] Impurities present will make gas oil to difficult to separate.

7. What is the temperature range possibly applied in the coking unit?
a) 480-570 degrees
b) 570-680 degrees
c) 680-740 degrees
d) 740-890 degrees

View Answer

Answer: a [Reason:] It is the optimum range for the coking to take place and to move it to higher temperature.

8. What should be introduced in the reactor to maintain satisfactory size distribution of coke?
a) Coke particles
b) Steam
c) Gas oil
d) None of the mentioned

View Answer

Answer: a [Reason:] Coke fines are introduced to help in propagation of crystal growth.

9. Why do we need a heater along with the reactor in coking unit?
a) Regenerator
b) Recycle
c) Reuse
d) Reheat

View Answer

Answer: d [Reason:] We are reheating coke at higher temperature for removing moisture.

10. What temperature should be maintained in the heater before the coke product comes out?
a) 480-570 degrees
b) 590-650 degrees
c) 680-740 degrees
d) 740-890 degrees

View Answer

Answer: b [Reason:] For drying of moisture in the coke.

Set 3

1. What is the maximum range of inclination, in the Fuller Huron air slide conveyor?
a) 1-3 degrees
b) 3-6 degrees
c) 6-9 degrees
d) 9-12 degrees

View Answer

Answer: b [Reason:] 3-6 degrees is the optimum range which is required for transportation.

2. What is the application of the process mentioned in below fig?
fluidization-engineering-questions-answers-freshers-q2
a) Transportation
b) Mixing
c) Reaction
d) Segregation

View Answer

Answer: a [Reason:] Fuller Air slide principle is used for transportation.

3. In below fig, how is the mixing of powdered particles taking place?
fluidization-engineering-questions-answers-freshers-q3
a) Water
b) Air
c) Steam
d) None of the mentioned

View Answer

Answer: b [Reason:] Air is used for developing the fluidized condition inside the mixer.

4. From above fig, if the inlet and outlet of solids are interchanged how would it impact the process?
a) No effect on the process
b) Practically not possible
c) Will require pumps
d) Leads to entrainment of solids by increasing air flow rate

View Answer

Answer: d [Reason:] Leads to loss of solid particles which is not desirable.

5. From above fig, if the solids inlet is interchanged with air inlet how would it impact the process?
a) Increases the load on the pumps
b) Difficulty for solids outlet
c) No proper mixing
d) All of the mentioned

View Answer

Answer: d [Reason:] All the problems will be encountered if that’s the case.

6. What is the best way for reducing load on cyclone separators in the fluidized mixer for powdery material?
a) Using multiple cyclones
b) Increasing the gas flow rate
c) Increasing the solids mass rate
d) None of the mentioned

View Answer

Answer: a [Reason:] Using of multiple cyclones will reduce load on them but at the same time its costly.

7. What is the latest technology being used for transportation of solid particles in cement industries?
a) Pneumatic fluidized transportation
b) Conveyor belts
c) Buckets
d) Trucks

View Answer

Answer: a [Reason:] Because it is cheaper than other transportation means.

8. Among the following processes which provides the most economic means in cement industry?
a) Fluidization process
b) Mixing process with agitator
c) Batch Reactor
d) All of the mentioned

View Answer

Answer: a [Reason:] It helps in reduction of cost and power.

9. Transportation through fluidization using more power than any other process, true or false?
a) True
b) False

View Answer

Answer: b [Reason:] Its the opposite, it uses least power.

10. What happens if the inclination is more than 3-6 degrees in the fuller Huron conveyor?
a) Difficulty in laying transportation lines
b) Faster transportation
c) Slows down the transportation
d) Has no effect

View Answer

Answer: a [Reason:] Creates problem while laying transportation lines on a larger scale.

Set 4

1. Why are the fluidized bed extensively used for heat exchangers, in both physical and chemical processes?
a) Ability to rapidly transport heat
b) Maintain uniform temperature
c) Utilization of entire area for heat distribution
d) All of the mentioned

View Answer

Answer: d [Reason:] Because all the above mentioned are achieved.

Questions (2-4) based on below fig;
2. What are the solids/liquid that is flowing from (1) ?
fluidization-engineering-questions-answers-heat-exchanger-q2
a) Hot alumina
b) Hot air
c) Steam
d) Sand particles

View Answer

Answer: a [Reason:] Since it is fluidized cooler for hot alumina particles.

3. From above fig, what is the maximum number turns of pipes inside the fluidized cooler?
a) 5-10 turns
b) 10-15 turns
c) 15-20 turns
d) Depending on the area provided

View Answer

Answer: d [Reason:] It depends on how much area has been provided irrespective of the number of turns.

4. From above fig, if the numbers represented as (1) and (2) are interchanged, i.e. the inlet components are reversed, will it have any effect on the process?
a) No effect
b) Slows down the productivity
c) Helps in increasing the cooling of hot alumina
d) Incomplete cooling

View Answer

Answer: b [Reason:] Since the amount of flow of alumina is less.

5. In order to efficiently recover heat from exit gases from a rotary kiln for cement clinker, how should be the solids present?
a) Agglomerated and palletized
b) Made into fine dust of 200 mesh
c) Should be of 10-15 microns
d) It doesn’t matter

View Answer

Answer: a [Reason:] Otherwise it will lead to clogging of distributor.

6. How useful is the fluidized bed for quenching or freezing hot reacting mixtures?
a) Intermediates
b) Fast cooling
C) Crystallization
d) Slow heat transfer

View Answer

Answer: a [Reason:] To obtain useful reaction intermediates.

7. Fig.8, Counter current heat exchanger developed by Russian engineers, mention the height of the bed?
a) 8m
b) 18m
c) 25m
d) 5m

View Answer

Answer: a [Reason:] Optimum height found by research.

8. What is the maximum pallets size required before it is to be used in fig.8?
a) 3-4mm
b) 1-2mm
c) 8-10mm
d) 5-8mm

View Answer

Answer: a [Reason:] Found during research, it is optimum range.

9. In counter current heat exchanger, the intermediate temperature is 800-900 degrees, true or false?
a) True
b) False

View Answer

Answer: a [Reason:] That temperature should be maintained for better heat exchanger.

10. Is it possible for fluidized heat exchangers to transfer heat for heat sensitive processes?
a) Yes, its possible
b) No, its difficult
c) Yes, its difficult
d) No, its possible

View Answer

Answer: a [Reason:] By controlling the gas flow rate its possible.

Set 5

1. Calcination of limestone and dolomite takes place at which temperature(degree Celsius)?
a) 100
b) 500
c) 1000
d) 2000

View Answer

Answer: c [Reason:] Calcination generally takes place at high temperatures in order to break the bonds.

2. Calcination of limestone is what kind of reaction?
a) Endothermic
b) Exothermic
c) Reversible
d) None of the mentioned

View Answer

Answer: a [Reason:] Since for breaking binds, lot of energy is utilized and hance they use more heat energy.

3. In order to recover most of the heat produced, which kind of staging is used in fluidized bed?
a) Single stage
b) Multi-stage
c) Stages in series
d) None of the mentioned

View Answer

Answer: b [Reason:] Multi-stage is required for multiple contacting and hence more heat is recovered.

4. Commercial limestone calciner, developed in 1949, for New England Lime company, it had diameter of?
a) 4 meters
b) 8 meters
c) 2 meters
d) 10 meters

View Answer

Answer: a [Reason:] Based on the data from White and Kinsalla, they developed calciner of 4 meters diameter.

5. Commercial limestone calciner, developed in 1949, for New England Lime company, it had height of?
a) 14 meters
b) 18 meters
c) 12 meters
d) 15 meters

View Answer

Answer: a [Reason:] Based on the data from White and Kinsalla, they developed calciner of 14 meters height.

6. Commercial limestone calciner, developed in 1949, for New England Lime company, they used feed of mesh?
a) 6 to 65
b) 8 to 85
c) 2 to 125
d) 200

View Answer

Answer: a [Reason:] Based on the data from White and Kinsalla, they used feed mesh ranging from 6 to 65 mesh.

7. In calcination stage, how many nozzles where used to spray fuel oil?
a) 5
b) 10
c) 12
d) 18

View Answer

Answer: c [Reason:] Based on the data from White and Kinsalla, they used 12 nozzles for spraying fuel oil.

8. What is the percentage conversion of overflow product in the calciner?
a) 95.4%
b) 75.3%
c) 96.8%
d) 99.7%

View Answer

Answer: c [Reason:] Based on the data from White and Kinsalla, they acheived 96.8% of overflow conversion product.

9. For the process of pelletization, which material is added in order to make it sticky?
a) Soda ash or caustic soda
b) Crude oil
c) Salt and water
d) All of the mentioned

View Answer

Answer: a [Reason:] By added soda ash or caustic soda, the surface of pellets becomes sticky and coated with fines.

10. To upgrade the poor quality phosphate rock, Dorr-Oliver made few modification such as?
a) Three-stage fluidized bed
b) 5 meters diameter
c) Height 12 meters
d) All of the mentioned

View Answer

Answer: d [Reason:] Above specifications were incorporated for in their design.