A. Inadequate ventilation
B. Low temperature oxidation
C. Storage in large heaps with small surface to volume ratio
D. All A., B. and C.
Related Mcqs:
- Improper storage condition results in the weathering of coal and spontaneous combustion, which increases its_________________?
A. Caking index
B. Yield of carbonised products
C. Friability & oxygen content
D. Calorific value - To avoid fire by spontaneous combustion of coal due to its low temperature oxidation, it should be stored in___________________?
A. Shallow and small piles
B. Fine sizes without the presence of any lump
C. Closed space without any ventilation facility
D. Large heaps with small surface to volume ratio - Low temperature oxidation and spontaneous combustion of freshly mined coal is accentuated, if __________________?
A. It contains large amount of volatile matter
B. It is stored in tall heaps
C. Smaller fines are stored in large quantity
D. All A., B. and C. - Fuel combustion is never cent per cent efficient due to___________________?
A. Incomplete combustion
B. Dry gas/stack gas loss
C. Moisture loss
D. All A., B. and 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 - Calorific value of coal middling generated in coal washeries during washing of coal may be around _____________ Kcal/kg?
A. 1000
B. 4000
C. 6000
D. 8000 - Rate of low temperature oxidation of coal due to bad storage conditions_______________?
A. Decreases with increase in surface area
B. Does not vary with increase in surface area
C. Is more for low volatile coal compared to high volatile coal
D. Is accelerated by storage in large heaps with small surface to volume ratio - Use of excess of combustion air in the combustion of fuels results in__________________?
A. Heat losses
B. Long flame
C. Condensation of water vapour from the fuel gas
D. None of these - Deficiency of combustion air during combustion of a gaseous fuel_____________________?
A. Lengthens the flame
B. Causes heat loss of fuel by its partial combustion
C. Both A. & B.
D. Shortens the flame - Which of the following is not applicable to fluidised bed combustion of coal ?
A. It cannot burn low grade coal
B. It achieves higher fuel combustion efficiency
C. Less heat transfer surface area is required in boilers
D. None of these
