Fuels and Combustion MCQs

Question 1

The maximum adiabatic flame temperature in air as compared to that in pure oxygen is

Accepted Answer

Much lower

Answer

Much higher

Answer

Same

Answer

Either lower or higher, depends on the type of fuel

Question 2

Coke made in narrower by-product coke ovens (as compared to wider ovens) is

Accepted Answer

All of the above

Answer

Less reactive

Answer

Stronger

Answer

Smaller in size

Question 3

Ammonia content in raw coke oven gas is about __________ gm/Nm3.

Accepted Answer

15

Answer

1

Answer

50

Answer

100

Question 4

Fusion point of coal ash increases with increase in its __________ content.

Accepted Answer

All of the above

Answer

Iron sulphate

Answer

Iron silicate

Answer

Lime and magnesia

Question 5

A coal with high ash content is undesirable, as

Accepted Answer

All of the above

Answer

It is abrasive to the coal pulveriser (ie.g. ball mill) and the combustion chamber

Answer

The ash in molten condition gets absorbed in the pores of the refractory lining of the furnace and causes its spalling due to different co-efficient of expansion/contraction of the refractory and the ash

Answer

The ash retains the sulphur & phosphorus and thus affects the quality of products in metallurgical furnace apart from increasing the slag volume. Besides, it may fuse and stick to the boiler tubes thereby reducing the heat transfer

Question 6

Fuel for a fast breeder nuclear reactor is

Accepted Answer

Plutonium

Answer

Uranium

Answer

Radium

Answer

Neptunium

Question 7

Water gas constitutes mainly of

Accepted Answer

CO & H2

Answer

CO & N2

Answer

CO2 & H2

Answer

CH4 & H2

Question 8

If the specific heat of gaseous products of combustion of a fuel is high, the abiabatic flame temperature will be

Accepted Answer

Low

Answer

High

Answer

Very high, if the fuel is of low calorific value

Answer

None of these

Question 9

C/H ratio is the maximum in case of

Accepted Answer

Coal

Answer

Furnace oil

Answer

Natural gas

Answer

Naphtha