The maximum heat loss is a boiler occurs due to
Moisture in fuel
Dry flue gases
Steam formation
Unburnt carbon
Correct Answer :
B. Dry flue gases
Related Questions
Pick up the wrong statement about water tube boiler in comparison to fire tube boilers
Former occupies less space for same power
Rate of steam flow is more in former case
Former is used for high installed capacity
Chances of explosion are less in former case.
A device used in a boiler to control the flow of steam from the boiler to the main pipe and to shut off the steam completely when required, is known as
Blow off cock
Fusible plug
Superheater
Stop valve
The diameter of a cylindrical shell of a Scotch marine boiler varies from
1.5 to 2 m
2.5 to 3.5 m
3.5 to 4.5 m
None of these
The critical pressure ratio for initially superheated steam is __________ as compared to initially dry saturated steam.
More
Less
Same
None of these
Lancashire boiler is
Stationary fire tube boiler
Internally fired boiler
Horizontal boiler
All of these
In water wall furnace, the heat is transferred to the water walls by
Convection
Radiation
Conduction
Radiation and conduction
Which of the following is a water tube boiler?
Locomotive boiler
Cochran boiler
Cornish boiler
Babcock and Wilcox boiler
During storage, the heating value of coal
Increases
Decreases
Remain constant
May increase or decrease depending upon the method of storage
The critical pressure ratio is given by (where p₁ = Initial pressure of steam, and p₂ = Pressure of steam at throat or critical pressure)
p₁. p₂
p₁/p₂
p₂/p₁
p₁ + p₂
Fire tube boilers are limited to a maximum working pressure of
0.17 MN/m²
1.7 MN/m²
17 MN/m²
170 MN/m²
The difference of supersaturated temperature and saturation temperature at that pressure is called
Degree of super-saturation
Degree of superheat
Degree of under-cooling
None of these
When steam after doing work in the cylinder passes into a condenser, the engine is said to be a
Slow speed engine
Vertical steam engine
Condensing steam engine
Non-condensing steam engine
The fusible plug in small boilers is located
In the drum
In the fire tubes
Above steam dome
Over the combustion chamber
The action of steam in a steam turbine is
Static
Dynamic
Static and dynamic
Neither static nor dynamic
Natural water circulation, by convection in water tube boilers, with increase in pressure of boiler
Increases
Decreases
Remain unaffected
First increases and then decreases
Which of the following statement is correct?
A horizontal steam engine requires less floor area than a vertical steam engine
The steam pressure in the cylinder is not allowed to fall below the atmospheric pressure
The compound steam engines are generally non-condensing steam engines
All of the above
The fire tubes in a Cochran boiler usually have _________ diameter.
6.25 mm
62.5 mm
72.5 mm
92.5 mm
Which of the following statement is wrong?
Locomotive boiler is a water tube boiler
Water tube boilers are internally fired
Lamont boiler is a low pressure water tube boiler
All of the above
In a 50% reaction turbine stage, tangential component of absolute velocity at rotor inlet is 537 m/s and the blade velocity is 454 m/s. The power output in kW of steam will be
260 kW
282 kW
296 kW
302 kW
The diameters of fire tubes and superheater tubes in locomotive boiler are
47.5 mm, 130 mm
32.5 mm, 180 mm
65.5 mm, 210 mm
24.5 mm, 65 mm
Which is not correct statement about effect of sulphur in fuel?
It has heating value
It helps in electrostatic precipitation of ash in flue gases
It leads to corrosion of air heaters, ducting, etc. if flue gas exit temperature is low
It erodes furnace walls
The amount of water evaporated in kg per kg of fuel burnt is called
Evaporative capacity of a boiler
Equivalent evaporation from and at 100° C
Boiler efficiency
None of these
In a receiver 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
Which of the following coals has the highest calorific value?
Anthracite coal
Bituminous coal
Lignite
Peat
De-Laval turbine is a
Simple impulse turbine
Simple reaction turbine
Impulse-reaction turbine
None of these
Duplex feed pumps are used in small steam boilers. These operate on the principle of
Centrifugal pump
Axial flow pump
Gear pump
Reciprocating pump
The working pressure range for a LaMont boiler is
0.5 to 10 MN/m²
1 to 15 MN/m²
2.5 to 15 MN/m²
3.5 to 20 MN/m²
The isentropic enthalpy drop in moving blade is two-third of the isentropic enthalpy drop in fixed blades of a turbine. The degree of reaction will be
0.4
0.56
0.67
1.67
An impulse turbine as compared to a reaction turbine, for a given power has _________ row of blades.
Equal
Less
More
None of these
The forced circulation of water does not take place in
LaMont boiler
Lancashire boiler
Velox boiler
Benson boiler