The temperature of flue gases at air heater outlet should be
100°C
Above dew point temperature of flue gases
Below dew point temperature of flue gases
Less than wet bulb temperature of flue gases
Correct Answer :
B. Above dew point temperature of flue gases
Related Questions
The selection of type and size of a steam boiler depends upon
The power required and working pressure
The geographical position of the power house
The fuel and water available
All of the above
Orsat meter is used for
Gravimetric analysis of the flue gases
Volumetric analysis of the flue gases
Mass flow of the flue gases
Measuring smoke density of flue gases
Lancashire boiler is a
Stationary fire tube boiler
Stationary water tube boiler
Water tube boiler with natural/forced circulation
Mobile fire tube boiler
Which of the following varieties of coals is mostly used in steam boilers?
Non-coking bituminous coal
Brown coal
Peat
None of the above
The pressure velocity compounded impulse turbine allows a bigger pressure drop and hence __________ numbers of stages are required.
More
Less
Equal
None of these
The ratio of the useful heat drop to the isentropic heat drop is called
Condenser efficiency
Nozzle efficiency
Boiler efficiency
Vacuum efficiency
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
The diameter of cylindrical shell of the Lancashire boiler is of the order of
1 to 1.25m
1 to 1.75 m
2 to 4 m
1.75 to 2.75 m.
The diameter of Cornish boiler is of the order of
12 m
1.52.5 m
23 m
2.53.5 m
The effect of friction on the flow of steam through a nozzle is to
Decrease the mass flow rate and to increase the wetness of steam
Increase the mass flow rate and to increase the exit temperature
Decrease the mass flow rate and to decrease the wetness of steam
Increase the exit temperature without any effect on mass flow rate
Which of the following is required for a steam condensing plant?
Condenser
Condensate pump
Air extraction pump
All of these
Maximum energy loss in a boiler occurs due to
Unburnt carbon in ash
Incomplete combustion
Ash content
Flue gases
The effect of bleeding is that
It increases the thermodynamic efficiency of the turbine
Boiler is supplied with hot water
It decreases the power developed by the turbine
All of the above
Which of the following is a fire tube boiler?
Lancashire boiler
Babcock and Wilcox boiler
Yarrow boiler
None of these
The function of a safety valve is
To blow off steam when the pressure of steam inside the boiler exceeds the working pressure
To indicate the water level inside the boiler to an observer
To measure pressure of steam inside the steam boiler
None of the above
The ratio of heat equivalent to brake power to the energy supplied in steam is known as
Mechanical efficiency
Overall efficiency
Indicated thermal efficiency
Brake thermal efficiency
By compounding the expansion of steam in two or more cylinders, the length of stroke
Does not change
Increases
Decreases
None of these
Bomb calorimeter is used to determine
Higher calorific value at constant volume
Lower calorific value at constant volume
Higher calorific value at constant pressure
Lower calorific value at constant pressure
The object of producing draught in a boiler is
To provide an adequate supply of air for the fuel combustion
To exhaust the gases of combustion from the combustion chamber
To discharge the gases of combustion to the atmosphere through the chimney
All of the above
A closed vessel made of steel and used for the generation of steam is called a
Steam boiler
Steam turbine
Steam condenser
Steam injector
For the same diameter and thickness of tube, a water tube boiler compared to a fire tube boiler has
More heating surface
Less heating surface
Equal heating surface
Heating surface depends on other parameters
The pressure at which latent heat of vaporisation of water is zero, is
Below atmospheric pressure
1 kg/cm²
100 kg/cm²
225.6 kg/cm²
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 of the following substance will have same percentage in both proximate and ultimate analysis?
Ash
Volatile matter
Moisture
Hydrogen
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 relative efficiency is defined as the
Ratio of thermal efficiency to Rankine efficiency
Ratio of brake power to the indicated power
Ratio of heat equivalent to indicated power to the energy supplied in steam
Product of thermal efficiency and Rankine efficiency
The draught may be produced by a
Mechanical fan
Chimney
A steam jet
All of these
In impulse turbines, when friction is neglected, the relative velocity of steam at outlet tip of the blade is __________ the relative velocity of steam at inlet tip of the blade.
Equal to
Less than
Greater than
None of these
The fittings mounted on the boiler for its proper and safe functioning is a
Water level indicator
Pressure gauge
Safety valve
All of these
By compounding the expansion of steam in two or more cylinders, the ratio of expansion
Does not change
Increases
Decreases
None of these