Fuels and Combustion MCQs

Question 1

Presence of free moisture in coal during its high temperature carbonisation

Accepted Answer

Protects the volatile products from pyrolysis (cracking) in the presence of hot coke and hot oven walls

Answer

Reduces the coking time

Answer

Increases the loss of fine coal dust from the ovens when charging

Answer

None of these

Question 2

Which of the following gaseous fuels is likely to have the highest gross calorific value?

Accepted Answer

LPG

Answer

Sewage gas

Answer

Producer gas

Answer

Natural gas

Question 3

Highly caking coals

Accepted Answer

Both B and C

Answer

Produce weak coke

Answer

Produce strong coke

Answer

May damage the coke oven walls during carbonisation

Question 4

Flue gas obtained on complete combustion of pure acetylene (a hydrocarbon fuel) will contain

Accepted Answer

Both B & C

Answer

CO

Answer

CO2

Answer

H2O

Question 5

For the case of a fuel gas undergoing combustion with air, if the air/fuel ratio is increased, the adiabatic flame temperature will

Accepted Answer

Decrease

Answer

Increase

Answer

Increase or decrease depending on the fuel type

Answer

Not change

Question 6

Lurgi gasifier (high pressure gasifier) as compared to Kopper Totzek gasifier (atmospheric pressure gasifier) produces

Accepted Answer

Both A & B

Answer

Higher amount of methane

Answer

Lower amount of hydrogen

Answer

Higher amount of both methane and hydrogen

Question 7

Out of the following fuels, the difference between the net and gross calorific value is maximum in case of

Accepted Answer

Fuel oil

Answer

Pitch

Answer

Blast furnace gas

Answer

Bituminous coal

Question 8

A good metallurgical coke should have very low

Accepted Answer

Sulphur & phosphorous content

Answer

Porosity

Answer

Fusion point of its ash

Answer

Hardness & strength

Question 9

Which is the most matured coal?

Accepted Answer

Anthracite

Answer

Lignite

Answer

Bituminous

Answer

Semi-anthracite