FUELS AND COMBUSTION QUIZ

Which of the following has the highest heat of combustion?

CH₄

CO

H₂

C₂H₆

TRUE ANSWER : ?
YOUR ANSWER : ?

Advantages of fluidised bed combustion are

Reduced NOx formation in flue gas

Lower furnace operating temperature

All of these

High heat transfer rate

TRUE ANSWER : ?
YOUR ANSWER : ?

Ratio of primary air to secondary air increases with increase in the rank of coal, because the

Oxygen content progressively decreases

Calorific value of the coal increases

High rank coals have higher amount of volatile matter

Ratio of fixed carbon to volatile matter increases

TRUE ANSWER : ?
YOUR ANSWER : ?

Coking coals are invariably

Anthracites

Lignites

Semi-anthracites

Bituminous coals

TRUE ANSWER : ?
YOUR ANSWER : ?

The maximum adiabatic flame temperature is attained, when the fuel is burnt with

More than theoretically required amount of air

Less than theoretically required amount of air

Theoretically required amount of oxygen

Theoretically required amount of air

TRUE ANSWER : ?
YOUR ANSWER : ?

Anthracite coal

Burns with short, bluish, yellow-tipped flame producing very little smoke

Ignites more easily than bituminous coal

Is essentially a coking coal

Contains more volatile matter than bituminous coal

TRUE ANSWER : ?
YOUR ANSWER : ?

Higher percentage of ash in coal meant for the production of metallurgical grade coke

Decreases the hardness of coke

Decreases the abrasion resistance of coke

None of these

Causes brittleness in steel

TRUE ANSWER : ?
YOUR ANSWER : ?

A sample of natural gas containing 80% methane (CH₄) and rest nitrogen (N₂) is burnt with 20% excess air. With 80% of the combustibles producing CO₂ and the reminder going to CO, the Orsat analysis in volume percent is

CO₂ : 6.39, CO : 1.60, O₂ : 3.99, H₂O:25.96, N₂:72.06

CO₂ : 7.60, CO : 1.90, O₂ : 4.75, N₂ : 85.74

CO₂ : 6.26, CO : 1.56, O₂ : 3.91, H₂O :15.66, N₂ : 72.60

CO₂ : 7.42, CO : 1.86, O₂ : 4.64, N₂:86.02

TRUE ANSWER : ?
YOUR ANSWER : ?

The advantage of firing pulverised coal in the furnace lies in the fact, that it

Permits the use of low fusion point ash coal

All of these

Accelerates the burning rate and economises on fuel combustion

Permits the use of high ash content coal

TRUE ANSWER : ?
YOUR ANSWER : ?

Which of the following is a primary fuel?

Blast furnace coke

Wood charcoal

Natural gas

Gasoline

TRUE ANSWER : ?
YOUR ANSWER : ?