Which of the following gases has the highest calorific value?
Producer gas
Coal gas
Water gas
Blast furnace gas
Correct Answer :
B. Coal gas
Related Questions
The efficiency of an impulse turbine is maximum when (where Vb = Blade speed, V = Absolute velocity of steam entering the blade, and α = Nozzle angle)
Vb = 0.5 V cosα
Vb = V cosα
Vb = 0.5 V² cosα
Vb = V² cosα
Size of boiler tubes is specified by
Mean diameter and thickness
Inside diameter and thickness
Outside diameter and thickness
Outside diameter and inside diameter
When the circulation of water, in a boiler, is by convection currents which are set up during the heating of water, then the boiler is known as
Internally fired boiler
Externally fired boiler
Natural circulation boiler
Forced circulation boiler
The high pressure boiler is one, which produces steam at a pressure more than
Atmospheric pressure
5 kg/cm²
10 kg/cm²
7580 kg/cm²
Willian's law states that the steam consumption per hour provided with a throttled governor is proportional to (where I.P. = Indicated power)
1/(I.P)
1/(I.P)²
I.P.
(I.P.)²
A condenser in a steam power plant
Increases expansion ratio of steam
Reduces back pressure of steam
Reduces temperature of exhaust steam
All of these
The basic job of feed water treatment in boilers is to overcome the problem of
Corrosion
Scale
Carryover
All of the above
In natural circulation 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
Which of the following is a water tube boiler?
Lancashire boiler
Babcock and Wilcox boiler
Locomotive boiler
Cochran boiler
The actual vacuum in a condenser is equal to
Barometric pressure + actual pressure
Barometric pressure - actual pressure
Gauge pressure + atmospheric pressure
Gauge pressure - atmospheric pressure
Which of the following statement is correct?
Lancashire boiler is a fire tube boiler.
Fire tube boilers are internally fired.
Babcock and Wilcox boiler is a water tube boiler.
All of the above
The crown of the fire box is made hemispherical in order to
Give maximum space
Give maximum strength
Withstand pressure inside boiler
Resist intense heat in fire box
The artificial draught is produced by
Steam jet
Centrifugal fan
Chimney
Both (A) and (B)
The reheat factor is the ratio of the
Cumulative heat drop to the isentropic heat drop
Isentropic heat drop to the heat supplied
Total useful heat drop to the total isentropic heat drop
None of the above
In an ideal impulse turbine, the
Absolute velocity at the inlet of moving blade is equal to that at the outlet
Relative velocity at the inlet of the moving blade is equal to that at the outlet
Axial velocity at inlet is equal to that at the outlet
Whirl velocity at inlet is equal to that at the outlet
Gusset stays in a boiler are provided to
Prevent the bulging of flat surfaces
Avoid explosion in furnace
Prevent leakage of hot flue gases
Support furnace freely from top
Pulverised fuel is used for
Better burning
More calorific value
Less radiation loss
Medium sized units
In a Parson's turbine stage, blade velocity is 320 m/s at the mean radius and rotor blade exit angle is 30°. For minimum kinetic energy of the steam leaving the stage, the steam velocity at the exit of the rotor will be
160/3 m/s
320/3 m/s
640/3 m/s
640 m/s
The ratio of heat actually used in producing the steam to the heat liberated in the furnace, is known as
Equivalent evaporation
Factor of evaporation
Boiler efficiency
Power of a boiler
The maximum discharge through a chimney occurs when the height of chimney is
Infinitely long
Around 200 meters
Equal to the height of the hot gas column producing draught
Outside temperature is very low
Latent heat of dry steam at atmospheric pressure is equal to
539 kcal/ kg
539 BTU/ lb
427 kcal/ kg
100 kcal/ kg
The expansion of steam, as it flows over the blades in reaction turbine, represents
Isothermal process
Isentropic process
Throttling process
Free expansion process
The draught produced by a steam jet issuing from a nozzle placed in the chimney is called
Induced steam jet draught
Chimney draught
Forced steam jet draught
None of these
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 maximum heat loss is a boiler occurs due to
Moisture in fuel
Dry flue gases
Steam formation
Unburnt carbon
Cochran boiler is a
Horizontal fire tube boiler
Horizontal water tube boiler
Vertical water tube boiler
Vertical fire tube boiler
Vacuum for reciprocating steam engines compared to steam turbines is
More
Equal
Less
Could be more or less depending on the size of plant
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 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
A double acting steam engine with a cylinder diameter of 190 mm and a stroke of 300 mm has a cut-off of 0.35. The expansion ratio for this engine is nearly
1.05
2.86
6.65
10.05