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

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

A

Ash disposal problem

B

Excessive fly ash discharge from the stack

C

Higher power consumption in its transportation

D

Erosion of induced draft fan blades

Pulverised coal used in boiler firing need not have

A

Less moisture content

B

High fusion point of its ash

C

High bulk density

D

Lower ash content

Use of pulverised coal in boiler furnace provides

A

High calorific value

B

Better combustion

C

Smokeless burning

D

Less erosion on furnace walls

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

A

Permits the use of high ash content coal

B

Permits the use of low fusion point ash coal

C

Accelerates the burning rate and economises on fuel consumption

D

All of the above

Function of secondary air in pulverised coal firing is to

A

Transport the coal to the burner

B

Dry the coal

C

Ensure efficient burning of coal around the burner

D

Reduce primary air requirement

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

A

Permits the use of high ash content coal

B

Permits the use of low fusion point ash coal

C

Accelerates the burning rate and economises on fuel combustion

D

All of the above

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

A

Transportation of coal

B

Drying of coal

C

Combustion of coal by supplying it around the burner

D

Preheating the primary air

Coal is pulverised before burning in large capacity boiler furnaces mainly to

A

Ensure its complete combustion

B

Facilitate easy ash removal

C

Enhance its calorific value

D

Provide trouble free operation

Combustion of pulverised coal as compared to that of lump coal

A

Develops a non-luminous flame

B

Develops a low temperature flame

C

Can be done with less excess air

D

Provides a lower rate of heat release

Combustion of pulverised coal compared to the lumpy coal

A

Provides better control of furnace temperature

B

Facilitates combustion with lower excess air

C

Provides higher thermal efficiency & flame temperature

D

All of the above

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

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