A. Ash disposal problem
B. Excessive fly-ash discharge from the stack
C. High power consumption in its transportation
D. Erosion of induced draft fan blades
Related Mcqs:
- 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 - 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 A., B. and C. - 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 - Which of the following will be unsuitable for dust cleaning from flue gas at 400°C from a pulverised coal fired boiler ?
A. Multicyclones
B. Bag filter
C. Wet scrubber
D. Hydrocyclones - 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 - Use of pulverised coal in boiler furnace provides___________________?
A. High calorific value
B. Better combustion
C. Smokeless burning
D. Less erosion on furnace walls - Temperature of preheated air used for the transportation of pulverised coal through pipes to the burner of a boiler furnace is restricted to a maximum limit of about 300° C to avoid the___________________?
A. Requirement of large volume combustion chamber
B. Risk of explosion
C. Chances of clinker formation
D. Incomplete combustion of coal - ombustion of pulverised coal compared to the lumpy coal __________________?
CA. Provides better control of furnace temperature
B. Facilitates combustion with lower excess air
C. Provides higher thermal efficiency & flame temperature
D. All A., B. & C. - 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
