A. Low reactivity of carbonised residue containing high proportions of iron & sulphur
B. Low forced draught and fuel bed temperature
C. Thick fire bed and preheated primary air
D. All A., B. and C.
Related Mcqs:
- A travelling grate stoker is meant for the efficient burning of ______________ coal?
A. Caking
B. Pulverised
C. Non-caking
D. High ash - Which of the following fuels is the best for burning on chain grate stoker ?
A. Non-caking coal
B. Caking coal
C. Coking coal
D. Pulverised coal - During combustion of coal on grate, clinker formation is increased by the___________________?
A. Use of thick fire bed
B. Low fusion point of ash (< 1100° C)
C. Use of preheated primary air
D. All A., B. & C. - 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 - “Overfire burning” in a furnace is a phenomenon characterised by the __________________?
A. Supply of excess fuel
B. Supply of excess air
C. Burning of carbon monoxide and other incombustibles in upper zone of furnace by supplying
more air
D. None of these - 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 - Efficient burning of anthracite coal requires______________________?
A. Low preheat of air
B. Fine grinding
C. High excess air
D. All A., B. and C - A particular coal is said to be free burning when it __________________?
A. Burns completely
B. Gives smokeless burning
C. Shows little or no fusing action
D. None of these - Correct viscosity of furnace oil at the burner tip for proper atomisation is about 25 centistokes. To reduce the viscosity of high viscosity furnace oil (250 centistokes) to the correct atomisation viscosity (i.e. 25 cst), it should be preheated to about ______________°C?
A. 70
B. 85
C. 105
D. 145 - Furnace oil consumption in a furnace for a given duty employing preheated combination air (at 300°) may be reduced by about ______________ percent as compared to the use of atmospheric combustion air?
A. 5
B. 10
C. 20
D. 35
