Fuels and Combustion MCQs

Question 1

In case of pulverised coal fired steam boiler, the secondary air serves the main purpose of

Accepted Answer

Combustion of coal by supplying it around the burner

Answer

Transportation of coal

Answer

Drying of coal

Answer

Preheating the primary air

Question 2

Grindability index of a coal is 100. It implies that the

Accepted Answer

Coal can be easily pulverised

Answer

Coal can be pulverised with great difficulty

Answer

Coal can't be pulverised

Answer

Power consumption in grinding the coal will be very high

Question 3

Heat penetration rate in narrow coke ovens in high temperature carbonisation of coal is around __________ cm/hr.

Accepted Answer

2.5

Answer

0.5

Answer

10

Answer

20

Question 4

The reaction, C + CO2 ⟷ 2CO, taking place during coal gasification is called the __________ reaction.

Accepted Answer

Boudouard

Answer

Neumann reversal

Answer

Shift conversion

Answer

Reduction

Question 5

Gross & net calorific value is the same for

Accepted Answer

L.D. converter gas

Answer

Blast furnace gas

Answer

Coke oven gas

Answer

None of these

Question 6

Which of the following constituents of a fuel does not contribute to its calorific value on combustion?

Accepted Answer

None of these

Answer

Hydrogen

Answer

Sulphur

Answer

Carbon

Question 7

Which of the following fuels has the highest calorific value per unit mass (kcal/kg)?

Accepted Answer

Furnace oil

Answer

Coal

Answer

Kerosene

Answer

Natural gas

Question 8

Tar is a better fuel than furnace oil, because of its

Accepted Answer

Both A & B

Answer

Higher calorific value

Answer

Lower sulphur content

Answer

Higher emissivity (0.8 - 0.9) resulting in higher radiation heat transfer rate

Question 9

When incomplete combustion loss is high, the flue gas analysis shows large amount of

Accepted Answer

CO

Answer

CO2

Answer

O2

Answer

C