Use of pulverised coal in boilers provides____________________?

Related Mcqs:

1. Very high pressure boilers are usually _____________ boilers?

   A. Fire tube
   B. Water tube
   C. Waste heat
   D. Natural circulation

2. 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

3. 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 A., B. and C.

4. Which of the following is the most important deterrents 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

5. Pulverised fuel fired furnaces employ ______________ fuel firing?

   A. Horizontal
   B. Vertical
   C. Tangential
   D. All A., B. and C.

6. Amount of coal lost in ash particle, which is carried through the boiler system, depends upon the__________________?

   A. Physical nature, ash content and fineness of the coal
   B. Amount of excess air supplied and load on the boiler
   C. Type of burner and combustion chamber
   D. All A., B. and C.

7. Which of the following accentuates clinkering troubles on furnace grate burning coal ?

   A. Low reactivity of carbonised residue containing high proportion of iron & sulphur
   B. Low forced draft & fuel bed temperature
   C. Thick firebed and preheated primary air
   D. All A., B. and C.

8. Overall thermal efficiency of a lumpy coal fired suitably designed heating furnace, if operated & maintained properly may be about ____________ percent?

   A. 10-15
   B. 25-30
   C. 45-50
   D. 65-70

9. Which of the following variables affects the furnace capacity ?

   A. Temperature of flue gas
   B. Thermal conductivity of stock
   C. Thickness of heating stock
   D. All A., B. and C.

10. Which of the following is not a directly fired furnace ?

    A. By-product coke oven
    B. Calcination kiln
    C. Sintering furnace
    D. Open hearth furnace