This set of Energy Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Applications of Biogas & Gasifier”.

1. What is the percentage at which rated power from biogas in petrol engine can be developed?
a) 45%
b) 65%
c) 75%
d) 85%
View Answer

Answer: d
Explanation: Petrol engine can be operated on biogas after initially starting with petrol. Petrol replacement of 1005 is possible and petrol engines can develop about 85% of rated power where as diesel engine can develop full power.

2. Which engine can run on dual fuel with little engine modification?
a) Diesel engine
b) Petrol engine
c) IC engine
d) External combustion engine
View Answer

Answer: a
Explanation: Diesel engine can run on dual fuel with little engine modifications. Advancing the injection timing and entry of biogas with intake air, it can be achieved by providing a mixing chamber below the air cleaner which facilitates mixing of biogas with air before entering into the cylinder.

3. Which of the SI engine can be run on biogas?
a) Diesel engine
b) Petrol engine
c) IC engine
d) External combustion engine
View Answer

Answer: b
Explanation: Petrol engine can run on biogas, but it is required to be started with petrol in the beginning. Petrol engine can be modified for operation on biogas including provision for entry of biogas, throttling of intake air and advancing ignition timing.

4. What does CNG stands?
a) Converted natural gas
b) Compressed natural gas
c) Compressed Non-soluble gas
d) Compressed natural gasoline
View Answer

Answer: b
Explanation: Compressed natural gas (CNG) (methane stored at high pressure) is a fuel which can be used in place of gasoline (petrol), Diesel fuel and propane/LPG. CNG combustion produces fewer undesirable gases than the fuels mentioned above.

5. What is the full form of VRA?
a) Vibration resistant appliance
b) Vehicle Refueling Appliances
c) Volatile removal assembly
d) Validated requirement authority
View Answer

Answer: b
Explanation: Vehicle refueling appliance is abbreviated as VRAs. Certified natural gas compressors for refueling the vehicles are commercially available. These allow refueling at home and work. After upgrading with the above-mentioned technologies, the biogas (transformed into biomethane) can be used as vehicle fuel in adapted vehicles.

6. A device for converting substances (chemically or physically) into gas is called ______
a) Gasifies
b) Biogas plants
c) Draughts
d) Gas chambers
View Answer

Answer: a
Explanation: The word Gasification implies converting a solid or liquid into a gaseous fuel without leaving any solid carbonaceous residue. Gasifier is a equipment which can gasify a variety of biomass such as wood waste, agricultural waste like stalks, and roots of various crops. The gasifier is essentially a chemical reactor where various complex physical and chemical processes take place.

7. How many types of gasifiers are there?
a) 2
b) 3
c) 4
d) 5
View Answer

Answer: c
Explanation: There are four types of gasifiers namely:
1. Up draught or counter current gasifier.
2. Down draught or co-current gasifier.
3. Cross draught gasifier.
4. Fluidized bed gasifier.

8. Which is the oldest and simplest type of gasifier?
a) Counter current gasifier
b) Cross draught gasifier
c) Co-current gasifier
d) Fluidized bed gasifier
View Answer

Answer: a
Explanation: The oldest and simplest type of gasifier is the counter current or up draught gasifier. The major advantage of this type of gasifier are its simplicity, high charcoal burnout and internal heat exchange leading to low gas exit temperatures and high equipment efficiency.

9. Which is the gasifier that can be operated in small scale/amounts?
a) Counter current gasifier
b) Cross draught gasifier
c) Co-current gasifier
d) Fluidized bed gasifier
View Answer

Answer: b
Explanation: It is actually the advantage of this system that it is capable of handling very small amounts for operation. Installations below 10 KW can under certain conditions be economically feasible. The reason is the very simple gas cleaning train which can be employed when using this type of gasifier.

10. Which gasifier has better tar converting capacity?
a) Counter current gasifier
b) Cross draught gasifier
c) Co-current gasifier
d) Fluidized bed gasifier
View Answer

Answer: c
Explanation: A solution to the problem of tar entrainment in the gas stream has been found by designing co-current or down draught gasifiers, in which primary gasification air is introduced at or above the oxidation zone in the gasifier.

11. Which gasifier has a minimum tar converting capability?
a) Counter current gasifier
b) Cross draught gasifier
c) Co-current gasifier
d) Fluidized bed gasifier
View Answer

Answer: b
Explanation: A disadvantage of cross draught gasifiers is their minimal tar converting capacity and the consequent needs for the high quality charcoal. It is because of the uncertainty of charcoal quality that a number of charcoal gasifiers employ down draught principle, in order to maintain at least a minimal tar cracking capability.

12. Which gasifier equipment has inability to operate on a number of unprocessed fuels?
a) Counter current gasifier
b) Cross draught gasifier
c) Co-current gasifier
d) Fluidized bed gasifier
View Answer

Answer: c
Explanation: Down draught gasifier or co-current gasifiers equipment lies in its inability to operate on a number of unprocessed fuels. In particular, fluffy, low density materials give rise to flow problems and excessive pressure drop and the solid fuel must be pelletized before use.

Sanfoundry Global Education & Learning Series – Energy Engineering.

To practice all areas of Energy Engineering, here is complete set of 1000+ Multiple Choice Questions and Answers.