Tertiary air is the air used to
Provide air around burners for obtaining optimum combustion
Transport and dry the coal
Cool the scanners
Convert CO (formed in lower zone of furnace) into CO₂ at higher zone.
Correct Answer :
D. Convert CO (formed in lower zone of furnace) into CO₂ at higher zone.
Related Questions
The radius of a dished head is taken approximately as
One fourth
Half
One
Two
The actual power generated in the engine cylinder is called
Indicated power
Brake power
Frictional power
None of these
The power of a boiler may be defined as
The ratio of heat actually used in producing the steam to the heat liberated in the furnace
The amount of water evaporated or steam produced in kg per kg of fuel burnt
The amount of water evaporated from and at 100° C into dry and saturated steam
The evaporation of 15.653 kg of water per hour from and at 100° C
A device used to increase the temperature of saturated steam without raising its pressure, is called
Blow off cock
Fusible plug
Superheater
Stop valve
The amount of water evaporated from feed water at _________ into dry and saturated steam at 100° C at normal atmospheric pressure is called equivalent evaporation from and at 100° C.
0°C
40°C
60°C
100°C
The condition of steam in boiler drum is always
Dry
Wet
Saturated
Supersaturated
In water wall furnace, the heat is transferred to the water walls by
Convection
Radiation
Conduction
Radiation and conduction
Willians line follows the law (where b = A constant representing the shape of the Willians line, a = Another constant i.e. no load consumption per hour, I.P. = Indicated power, and m = Steam consumption per hour)
I.P. = a × m + b
m = a + b × I.P.
I.P. = b × m + a
m = (b/I.P.) - a
The factor of evaporation for all boilers is always
Equal to unity
Less than unity
Greater than unity
None of these
When the speed of the crankshaft is between 100 r.p.m. and 250 r.p.m., the engine said to be a
Slow speed engine
Medium speed steam engine
High speed steam engine
None of these
Which device is used in thermal power plants to reduce level of pollution?
Induced draft fan
Smoke meter
Chimney
Precipitator
In order to obtain superheated steam, a superheater is added in an existing boiler. As as result, furnace vacuum will
Remain unaffected
Improve
Worsen
May improve/worsen depending on size
In forced recirculation type boiler,
Heating takes place at bottom and the water supplied at bottom gets converted into the mixture of steam bubbles and hot water which rise to drum
Water is supplied in drum and through down comers located in atmospheric condition it passes to the water wall and rises to drum in the form of mixture of water and steam
Feed pump is employed to supplement natural circulation in water wall type furnace
Water is converted into steam in one pass without any recirculation
The dry saturated steam at very high pressure (150200 kg/cm²) when throttled to atmosphere will become
Wet
Superheated
Remain dry saturated
Dry
Relative percentage of heat absorbed through the heat transfer of (i) Furnace water wall (ii) Boiler tank (iii) Superheater (iv) Economiser (v) Air-heater of a typical boiler of 200 MW capacity would be of the order of
48 : 20 : 15 : 7 : 10
10 : 7 : 15 : 20 : 48
20 : 48 : 7 : 15 : 10
7 : 15 : 20 : 10 : 48
Cochran boiler is a
Horizontal fire tube boiler
Horizontal water tube boiler
Vertical water tube boiler
Vertical fire tube boiler
In order to reduce the rotor speed of an impulse turbine, the method employed is
Velocity compounding
Pressure compounding
Pressure-velocity compounding
All of these
The pressure of feed water has to be raised before its entry into the boiler. The pressure is raised by a device known as
Feed pump
Injector
Feed check valve
Pressure gauge
The device attached to the steam chest for preventing explosions due to excessive internal pressure of steam is called
Safety valve
Water level indicator
Pressure gauge
Fusible plug
In a reaction turbine, when steam flows through the fixed blades,
Pressure increases while velocity decreases
Pressure decreases while velocity increases
Pressure and velocity both decreases
Pressure and velocity both increases
Which of the following compound steam engine requires a smaller flywheel?
Receiver type
Tandem type
Woolf type
All of these
For burning 1 kg of carbon to CO as per chemically correct combustion, amount of air required is
1 kg
4/3 kg
8/3 kg
2 kg
In an impulse turbine
The steam is expanded in nozzles only and there is a pressure drop and heat drop
The steam is expanded both in fixed and moving blades continuously
The steam is expanded in moving blades only
The pressure and temperature of steam remains constant
The ratio of the useful heat drop to the isentropic heat drop is called
Condenser efficiency
Nozzle efficiency
Boiler efficiency
Vacuum efficiency
In order to compare the capacity of boilers, the feed water temperature and working pressure are taken as
50°C and normal atmospheric pressure
50°C and 1.1 bar pressure
100°C and normal atmospheric pressure
100°C and 1.1 bar pressure
Multi-stage steam turbines are of the
Velocity compounded type
Reaction type
Pressure compounded type
All of these
O₂ content in atmospheric air on weight basis is
21 %
23 %
30 %
40 %
A compound steam engine in which the high pressure and low pressure cylinders have common piston rod, is called
Receiver type compound engine
Tandem type compound engine
Woolf type compound engine
None of these
The equivalent evaporation is defined as
The ratio of heat actually used in producing the steam to the heat liberated in the furnace
The amount of water evaporated or steam produced in kg per kg of fuel burnt
The amount of water evaporated from and at 100°C into dry and saturated steam
The evaporation of 15.653 kg of water per hour from and at 100°C
If a steam sample is nearly in dry condition, then its dryness fraction can be most accurately determined by
Throttling calorimeter
Separating calorimeter
Combined separating and throttling calorimeter
Bucket calorimeter