A. High rank coals have higher amount of volatile matter
B. Ratio of fixed carbon to volatile matter increases
C. Oxygen content progressively decreases
D. Calorific value of the coal increases
Related Mcqs:
- A coal having high ratio of volatile matter to fixed carbon as compared to a coal having low ratio of volatile matter to fixed carbon _________________?
A. Is less liable to spontaneous combustion on storage
B. Is more difficult to ignite and produces a shorter flame
C. Requires smaller combustion space and less secondary air
D. None of these - (64-132) rank coal (ASTM) means a coal with 64%___________________?
A. Fixed carbon and having a heat value of 13, 200 BTU/1b
B. Ash and a heating value of 13, 200 BTU/1b
C. Fixed carbon and a heating value of 132 BTU/1b
D. None of these - 64-132) rank coal (ASTM) means a coal with 64%___________________?
A. Fixed carbon and having a heating value around 13, 200 BTU/1b
B. Ash and heating value around 13, 200 BTU/1b
C. Fixed carbon and heating value around 132 BTU/1b
D. None of these - 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 - 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 - 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 - Fusion point of coal ash increases with increase in its ____________ content?
A. Iron sulphate
B. Iron silicate
C. Lime and magnesia
D. All A., B. and C. - The main function of primary air in pulverised coal fired burner is to_________________?
A. Burn CO to CO2
B. Dry and transport the coal
C. Have proper combustion by supplying it around the burner
D. Preheat the tertiary air used for complete combustion of CO to CO2 - For every 10% increase in the excess air; the fuel consumption increases by _______________ percent?
A. 0.1
B. 0.2
C. 0.5
D. 1.0 - As the C/H ratio of the fuel increases, the amount of CO2 formed on combustion _______________ for the same percentage of excess air?
A. Decreases
B. Increases
C. Remain same
D. May increase or decrease depending on the type of fuel
