Related Questions

Calorific value of a typical dry anthracite coal may be around __________ Kcal/kg.
A 1000
B 4000
C 8000
D 15000
Anthracite coal
A Contains more volatile matter than bituminous coal
B Ignites more easily than bituminous coal
C Is essentially a coking coal
D Burns with short, bluish, yellow-tipped flame producing very little smoke
A travelling grate stoker is meant for the efficient burning of __________ coal.
A Caking
B Pulverised
C Non-caking
D High ash
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
If h₁ = inner film co-efficient and /h₂ = outer film co-efficient, then the overall heat transfer co-efficient is
A Always less than h₁
B Always between h₁ and h₂
C Always higher than h₂
D Dependent on metal resistance
Anthracite can be used for
A Recarbonising steel
B Making carbon electrodes
C Blending with highly coking coal to check its swelling which helps in saving coke even walls from damage and to produce high strength coke
D All of the above
Ignition temperature decreases progressively from anthracite to lignite, because
A Volatile matter content increases
B Carbon content decreases
C Moisture content increases
D Ash content increases
Limestone powder is injected during pulverised coal burning in boilers to __________ the flue gases.
A Reduce SO2 content in
B Catalytically convert SO2 to SO3 in
C Increase the dew point of
D None of these
Which of the following accentuates clinker-ing 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 of the above
The open "Sigrees" or coal stoves often require fanning to sustain burning because of
A Tendency of carbon dioxide to form a layer along with dust smoke
B Lack of oxygen in the surroundings of sigrees
C Accumulation of smoke and dust over the sigrees
D Interrupted release of moisture from the material

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