FUELS AND COMBUSTION QUIZ

A liquid/gaseous fuel containing hydrocarbons and high amount of sulphur is burnt with 40% excess air. The flue gas still contains large amount of carbon monoxide. This may be due to the

Low calorific value of the fuel

Presence of large quantity of hydrogen in the fuel

Lack of thorough mixing of fuel with air

High sulphur content in the fuel

TRUE ANSWER : ?
YOUR ANSWER : ?

Which of the following fuel gases has the highest calorific value ?

Liquefied petroleum gas (LPG)

Natural gas

Coal bed methane (CBM)

Sewage gas

TRUE ANSWER : ?
YOUR ANSWER : ?

Which of the following combustibles is absent in blast furnace gas?

None of these

CH₄

CO

H₂

TRUE ANSWER : ?
YOUR ANSWER : ?

Calorific value of gobar gas (containing CH₄ = 60% , H₂ = 10% ; CO₂ = 30%) may be about __________ Kcal/Nm³.

3200

10200

5400

1800

TRUE ANSWER : ?
YOUR ANSWER : ?

Which of the following is not a by-product fuel?

Refinery gas

Petrol

Pitch

Blast furnace gas

TRUE ANSWER : ?
YOUR ANSWER : ?

Removal of hydrogen from coke oven gas

Does not alter its calorific value

Decreases its calorific value

Increases its calorific value

Is not possible on commerical scale

TRUE ANSWER : ?
YOUR ANSWER : ?

Presence of free moisture in coal during its high temperature carbonisation

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

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

Reduces the coking time

None of these

TRUE ANSWER : ?
YOUR ANSWER : ?

The main function of primary air in pulverised coal fired burner is to

Have proper combustion by supplying it around the burner

Burn CO to CO₂

Preheat the tertiary air used for complete combustion of CO to CO₂

Dry and transport the coal

TRUE ANSWER : ?
YOUR ANSWER : ?

Caking index of coal blend used for blast furnace coke making is about

12

36

22

8

TRUE ANSWER : ?
YOUR ANSWER : ?

Which of the following is the most important deterrents to an extended use of pulverised coal in boiler firing?

Ash disposal problem

High power consumption in its transportation

Excessive fly-ash discharge from the stack

Erosion of induced draft fan blades

TRUE ANSWER : ?
YOUR ANSWER : ?