Fuels and Combustion MCQs

Question 1

Optimum preheating temperature for pitch creosote mixture (PCM) which is also termed as C.T.F-200, before atomisation through burners is

Accepted Answer

200°F

Answer

200°C

Answer

200°K

Answer

200°R

Question 2

The sequence of absorption in flue gas analysis by Orsat's apparatus is respectively

Accepted Answer

CO2, O2, CO

Answer

CO, O2, CO2

Answer

CO2, CO, O2

Answer

O2, CO2, CO

Question 3

Bituminous coal

Accepted Answer

Both B and C

Answer

Ignites less easily than anthracite

Answer

Is generally coking

Answer

Burns with smoky yellow flame

Question 4

The main product of high temperature carbonisation of coal is

Accepted Answer

Coke

Answer

Ammonia

Answer

Tar

Answer

Coke oven gas

Question 5

With increase in the temperature of carbonisation of coal

Accepted Answer

All of the above

Answer

Hydrogen content of coke oven gas increases due to cracking of hydrocarbons

Answer

Methane content in the coke oven gas decreases and carbon monoxide content increases

Answer

Calorific value of the coke oven gas decreases due to cracking of hydrocarbons which is not compensated by increase in CO & H2 content

Question 6

Flue gas discharge velocity through chimney of a big thermal power plant may be around __________ m/sec.

Accepted Answer

10

Answer

0.5

Answer

50

Answer

500

Question 7

Beehive coke oven

Accepted Answer

Takes 2-3 days for coking of coal but requires no external fuel for heating

Answer

Facilitates by-products recovery

Answer

Gives larger yield of coke (around 85%) as compared to by-product ovens

Answer

Produces coke with very poor strength

Question 8

Fuel gases containing hydrocarbons (ie.g. coke oven gas) are not preheated before burning, mainly because

Accepted Answer

The hydrocarbons crack thereby choking and fouling the heat transfer surface by carbon soot

Answer

It reduces its calorific value tremendously

Answer

It reduces its flame temperature tremendously

Answer

There are chances of explosion during preheating

Question 9

Pick out the wrong statement.

Accepted Answer

The minimum temperature, at which a petroleum oil vapor catches fire and continues to burn, is called its flash point

Answer

LPG is also used as fuel for automobiles & small furnaces and for cutting & welding of metals

Answer

Each ton of petroleum oil on distillation produces about 30 - 50 Nm3 of gas

Answer

Maximum yield of naphthalene is obtained on distillation of crude oil