Spontaneous combustion is a phenomenon in which

A All the fuel burns instantaneously producing high energy release
B Fuel burns with less air
C Coal bursts into flame without any external ignition source but by itself due to gradual increase in temperature as a result of heat released by combination of oxygen with coal
D Explosion in furnace

Correct Answer: Coal bursts into flame without any external ignition source but by itself due to gradual increase in temperature as a result of heat released by combination of oxygen with coal

Bissoy MCQ
#Mechanical Engineering #Steam Boilers #Engines #Nozzles And Turbines

Related Questions

Improper storage condition results in the weathering of coal and spontaneous combustion, which increases its
A friability & oxygen content
B caking index
C yield of carbonized products
D calorific value
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 of the above
Pre-ignition is caused by the spontaneous combustion of the mixture before the end of the compression stroke, and is due to
A Cylinder walls being too hot
B Overheated spark plug points
C Red hot carbon deposits on cylinder walls
D Any one of these
Spontaneous combustion of coal on storage results due to
A Inadequate ventilation
B Low temperature oxidation
C Storage in large heaps with small surface to volume ratio
D All of the above
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
Radioactivity is a phenomenon of the spontaneous emission of
A protons (alpha particles)
B electrons (beta particles)
C gamma rays (short wave electromagnetic waves)
D All of the above
The most commonly used combustion system manufactured in India for the thermal power plant boilers is the __________ combustion system.
A Pulverised fuel
B Travelling grate stoker firing
C Circulating fluidised bed
D Fluidised bed
The combustion efficiency of a gas turbine using perfect combustion chamber is of the order of
A 75%
B 85%
C 90%
D 99%
In an internal combustion engine, the process of removing the burnt gases from the combustion chamber of the engine cylinder is known as
A Scavenging
B Detonation
C Supercharging
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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

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