An air preheater is installed
Before the economiser
Before the superheater
Between the economiser and chimney
None of these
Correct Answer :
C. Between the economiser and chimney
Related Questions
Boiler stays are used to
Prevent flat surfaces under pressure from tearing apart
Take care of failure in shear
Take care of failure in compression
Provide support for boiler
In a boiler, the heat is lost
To dry flue gases
In moisture present in the fuel
To steam formed by combustion of hydrogen per kg of fuel
All of the above
Feed water conditioning in thermal power plants in done to
Reduce hardness and for removal of solids
Increase efficiency of thermal power plant
Increase heat transfer rate
Increase steam parameters
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
Latent heat of dry steam at atmospheric pressure is equal to
539 kcal/ kg
539 BTU/ lb
427 kcal/ kg
100 kcal/ kg
A throttle governed steam engine develops 15 kW with 280 kg per hour of steam and 35 kW with 520 kg per hour of steam. The steam consumption in kg per hour when developing 20 kW will be nearly
150 kg/h
210 kg/h
280 kg/h
340 kg/h
The length of Cornish boiler varies from
2 to 4.5 m
3 to 5 m
5 to 7.5 m
7 to 9 m
The balanced draft furnace is one using
Induced draft fan and chimney
Induced draft fan and forced draft fan
Forced draft fan and chimney
Any one of the above
A single stage impulse turbine with a diameter of 1.2 m runs at 3000 r.p.m. If the blade speed ratio is 0.42, then the inlet velocity of steam will be
79 m/s
188 m/s
450 m/s
900 m/s
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
A stage, in reaction turbine, is represented by
Number of casing
Number of entries of steam
Number of exits of steam
Each row of blades
Equivalent evaporation of water is the evaporation for a feed water supply at 100°C
And its corresponding conversion into dry saturated steam at 100°C and 1.033 kg/cm²
And its corresponding conversion into dry steam at desired boiler pressure
Conversion into steam at atmospheric condition
Conversion into steam at the same pressure at which feed water is supplied
The value of the reheat factor varies from
1.02 to 1.06
1.08 to 1.10
1.2 to 1.6
1.6 to 2
In a steam condenser, the partial pressure of steam and air are 0.06 bar and 0.007 bar respectively. The condenser pressure is
0.007 bar
0.053 bar
0.06 bar
0.067 bar
Which of the following statement is correct?
The efficiency of steam turbines is greater than steam engines
A flywheel is a must for steam turbine
The turbine blades do not change the direction of steam issuing from the nozzle
The pressure of steam, in reaction turbines, is increased in fixed blades as well as in moving blades
Cut-off ratio is the ratio of
Swept volume to the volume at cut-off
Volume at cut-off to the clearance volume
Volume at cut-off to the swept volume
Clearance volume to the volume at cut-off
The ratio of the useful heat drop to the isentropic heat drop is called
Condenser efficiency
Nozzle efficiency
Boiler efficiency
Vacuum efficiency
When the cross-section of a nozzle increases continuously from entrance to exit, it is called a
Divergent nozzle
Convergent nozzle
Convergent-divergent nozzle
None of these
In a reaction turbine when the degree of reaction is zero, then there is
No heat drop in moving blades
No heat drop in fixed blades
Maximum heat drop in moving blades
Maximum heat drop in fixed blades
A safety valve mainly used with locomotive and marine boilers is
Lever safety valve
Dead weight safety valve
High steam and low water safety valve
Spring loaded safety valve
In locomotive boiler, maximum steam pressure is limited to
1 kg/cm²
5 kg/cm²
10 kg/cm²
18 kg/cm²
In a Tandem type compound engine, the high pressure and low pressure cylinders
Have common piston rod
Are set at 90°
Have separate piston rods
Are set in V-arrangement
Pick up the wrong statement about critical condition of steam
Latent heat is zero
Liquid directly becomes steam
Specific volume of steam and liquid is same
This is the maximum pressure limit
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.
Which of the following boiler is best suited to meet the fluctuating demand of steam?
Locomotive boiler
Lancashire boiler
Cornish boiler
Babcock and Wilcox boiler
Thermal equilibrium means that the flow of steam is
Isothermal
Isentropic
Hyperbolic
Polytropic
The function of a crosshead is to guide motion of the _________ and to prevent it from bending.
Piston rod
Connecting rod
Eccentric rod
Valve rod
In which of the following boilers, the draught in furnace is increased by utilising exhaust steam from engine
Lancashire boiler
Locomotive boiler
Babcock and Wilcox boiler
Benson boiler
For water, at pressures below atmospheric;
Melting point rises slightly and boiling point drops markedly
Melting point rises markedly and boiling point drops markedly
Melting point drops slightly and boiling point drops markedly
Melting point drops slightly and boiling point drops slightly
Thermal efficiency of well maintained boiler will be of the order
40 %
50 %
75 %
90 %