200 Top Steam Boilers, Engines, Nozzles and Turbines Mechanical Engineering Multiple Choice Questions and Answers List Flashcards
1
Q
For water~ at pressures below atmospheric,
(a) melting point rises slightly and boiling point drops markedly
(b) melt ing point rises markedly and boiling point drops markedly
(c) melting point drops slightly and boiling point drops markedly
(d) melting point drops slightly and boiling point drops slightly
(e) none of the above.
A
melting point rises slightly and boiling point drops markedly
2
Q
At very tow temperature, the melting and bolllno temperatures become equal. This temperature is
(a) 373°K
( b) 273.16°K
(c) 303K
{d) 0K.
( e) 300*K
A
273.16°K
3
Q
The latent heat of steam at pressures greater than atmospheric In comparison to latent heat at atmospheric pressure is
(a) less
( b) more
(c) equal
(d) may be less or more depending on temperature
(e) unpredictable.
A
less
3
Q
The critical pressure at which Jatent heat of vaporisat1on is zero is
(a) 225 .65 kgf/cm2
{b) 273 kgf/cm2
(c) 100 kgf/cm2
(d) 1 kgf/cm2
(e) * 1 kgf/cm2.
A
225 .65 kgf/cm2
4
Q
The saturation temperature of steam with increase In pressure increases
(a) linearly
( b) rapidly first and then slowly
(c) slowly first and then rapidly
(d) inversely
(e) non e of the above.
A
rapidly first and then slowly
5
Q
Carbonlsatlon of coal is t he process of
(a) pulverising coal in inert atmosphere
( b) heating wood in a llmit4Mt supply of air at temperatures below 300°C
(c) strongly heating coal continuously for about 48 hours In the absence of air in a closed vessel
(d) binding the pulverised coal into brick-ettes
(e) enriching carbon In the coal.
A
strongly heating coal continuously for about 48 hours In the absence of air in a closed vessel
5
Q
Coke is produced by
(a) pulverising coal in Inert atmosphere
( b) hea ting wood in a limited supply of air at temperatures below 300GC
(c) strongly heating coa1 continuously for about 48 hours In the absence of air in a closed vessel
(d) bincling the pulverised coal into brick-etts
(e) enriching carbon in the coal.
A
strongly heating coal continuously for about 48 hours In the absence of air in a closed vessel
5
Q
Heat ing of dry steam above saturation temperature is known as
(a) enthalpy
(b) superheating
(c) supersaturation
(d) latent heat
(e) super tempering.
A
superheating
6
Q
Superheating of steam is done at
(a) constant volume
( b) constant temperatu re
(c) constant pressure
(d) constant entropy
(e) constant enthaply.
A
constant pressure
7
Q
1 kg.m is equal to
(a) 9 .81 Joules
( b) All Joules
(c) 427 Joules
(d) 102 Joules
(e) 539 Joules.
A
9 .81 Joules
8
Q
If partial pressure of air and steam be pa and ps respectively in a condenser, then according to Dalton’s law, the
pressure in condenser is equal to
(a) Ps-Pa
(b) pa-ps
(C) Pa +P,
A
Pa +P,
9
Q
Equiva lent evaporation is the amount of water evaporated in a boiler from and at
(a) oc
(b) 1ooc
(c) sat urat ion temperature at given pressure
(d) room temperature
(e) 2o*c.
A
100*c
10
Q
The spedfic volume of steam with increase in pressure decreases
(a) linearly
( b) slowly first and then rapidly
(c) rapidly first and then slowly
(d) inversely
(e) none of the above.
A
rapidly first and then slowly
11
Q
The equivalent evaporation of a boiler is a measure to compare
(a) the given boiler with the model
(b) the two different boilers of t he same make
(c) two different makes of boi lers operat-,ing under the same operating conditions
(d) two boilers of same make but opera ing under different conditions
(e) any type of boilers operating under any conditions.
A
any type of boilers operating under any conditions.
12
Q
The coal requirement per kW hour generation in the thermal power plant is of the order of
(a) 0. 1 to 0.2 kg
(b) 0 .2 to 0.4 kg
(c) 0.6 to 0.8 kg
(d) 1.0 to 1.5 kg
(e) 1.5 to 2 kg.
A
0.6 to 0.8 kg
13
Q
Sublimation region is the region where
(a) solid and vapour phases are in equlibrium
( b) solid and liqu id phases are in equilibrium
(c) liquid and vapour phases are in equilibrium
(d) solid, liquid and vapou r phases are in equilibrium
(e) none of the above.
A
solid and vapour phases are in equlibrium
14
Q
Stoichiometric quantity of air is the
(a) air present in atmosphere at NTP conditions
( b) air required for complete combustion of fuel with no excess air
(c) air required for optimum combustion so as to have reasonable excess air
(d) air required to convert CO into C02
(e) air required to form an explosive mixture.
A
air required for complete combustion of fuel with no excess air
15
Q
One kg of steam sample contains 0.8 kg dry steam; it’s dryness fraction is
(a) 0.2
( b) 0.8
(c) 1.0
(d) 0.6
(e) 0 .5.
A
0.8
16
Q
If a steam sample is nearly in dry condition, then its dryness fraction can be most accurately determined by
(a) throttling calorimeter
( b) separat ing calorimeter
(c) combined separating and throttl ing calorimeter
(d) bucket calorimeter
(e) none of the above.
A
throttling calorimeter
17
Q
If xx and x2 be the dry fraction s obtained in separating calorimeter and throttling calorimeter respectively, then the actual dryness fraction of steam will be
(a) xxx2
(b)x, + x2
A
xxx2
17
Q
The specific heat of superheated steam in kcal/kg is generally of the order of
(a) 0.1
(b) 0.3
(c) 0.5
(d) 0.8
(e) 1.0.
A
0.8
18
Q
On Mollier chart, flow through turbine is represented by’
(a) horizontal straight line
(b) vertical straight line
{c) straight inclined line
(d) curved line
{e) none of the above.
A
vertical straight line
19
Q
A wet vapour can be com pletely specified by
(a) pressure only
{b) tem perature only
(c) dryness fraction only
(d) specific volume only
{e) pressure and dryness fraction
A
pressure and dryness fraction
20
Q
On Mill ier chart1 the constant pressure lines
(a) diverge from left to right
(b) diverge from right to left
(c) are equally spaced t hroughout
(d) first rise up and t hen fall
{e) none of the above.
A
diverge from left to right
21
On Mollier chart, free expansion, or t hrottling process from high pressure to atmosphere is represen ted by
{a) horizontal straight line
{b) vertical straight line
(c) straight inclined line
(d) curved line
(e) none of the above.
horizontal straight line
22
The bituminous coal is non-caking if its carbon content is
(a) 78-81%
(b) 8 1-85%
(C) 85-90%
(d) 90-95%
(e) 95-100%.
78-81%
23
The dry saturated steam at very low pressure, (5- 10 kg/cm 2) w hen t hrottl ed to atmosphere w ill become
(a) wet
(b) superheated
(c) remain dry satruated
(d) dry
{e) none of the above.
superheated
24
Water at pressure of 4 kg/cm2 and 1600C t emperat ure when exposed to atmosphere w ill
(a) boil
{b) flash i.e. get converted into steam
(c) remain as it was
(d) cool down
{e) none of the above.
flash i.e. get converted into steam
25
The dry saturated steam at very high press.ure (150-200 kg/cm2) when throttled to atmosphere will become
(a) wet
(b) superheated
(c) remain dry saturated
(d) dry
(e) none of the above.
wet
26
In a throttling process
{a) steam temperature remaisn constant
(b) steam pressure remains constant
(c) steam enthalpy remains constant
{d) steam entropy rema ins constant
(e) steam volume remains constant.
steam enthalpy remains constant
27
In a throttling process
{a) heat transfer takes place
(b) work is done by t he expanding steam
{c) internal energy of steam changes
(d) all of the above
(e) none of the above.
none of the above.
28
The pressure at which latent heat of vaporisation of water is zero, is
{a) below atmospheric pressure
(b) 1 kg/cm2
(c) 100 kg/cm2
(d) 170 kg/cm2
(e) 225.6 kg/cm2.
225.6 kg/cm2.
29
latent heat of dry steam at atmospneric pressure is equal to
(a) 539 kcal/kg
(b) 539 BTU/Ib
(c) 427 kcal/kg
(d) 100 kcal/kg
(e) 471 kcal/kg.
539 kcal/kg
30
The latent heat of steam with ino-ease of pressure
(a) remains same
(b) increases
{c) decreases
(d) behaves unpredictably
(e) none of the above.
decreases
31
At critical point, i.e. p=225.65 kg/cm2, t he latent enthalpy o f vaporisation is
(a) maximum
(b) minimum
(c) zero
(d) depends on temperature also
{e) none of the above.
zero
32
At which pressure the properties of water and steam become identical
(a) 0. 1 kg/cm2
(b) 1 kg/cm2
(c) 100 kg/cm2
(d) 225.6 kg/cm2
(e) it is never possible.
225.6 kg/cm2
33
In an experiment to determine dryness fraction of steam, the mass of water separated was 1.2 kg in 15 mts and the
mass of steam passed out in same time was 4.8 kg. Dryness fraction is
(a)40%
(b) 25%
(c) 50%
(d) 80%
(e)90%.
80%
34
While steam expands in t urbines, theoretically t he entropy
(a) remains constant
(b) increases
(c) decreases
(d) behaves unpredictably
(e) none of the above.
remains constant
35
Heating wet steam at constant temperature is heating it at constant
(a) volume
(b) pressure
(c) entropy
(d) enthalpy
(e) none of t he above.
pressure
36
Adiabatic process is
(a) essentially an isentropic process
(b) non-heat transfer process
(c) reversible process
(d) constant temperatu re process
(e) constant enthalpy process.
non-heat transfer process
37
The state of vapour under saturation condition is described by
(a) pressure alone
(b) temperature alone
(c) pressure and temperatu re
(d) pressure and dryness fraction
(e) dryness fraction alone.
pressure and dryness fraction
37
Pick up the wrong statement about critical condition of steam
(a) latent heat is zero
(b) liquid directly becomes steam
(c) specific volume of steam and liquid is same
(d) this is the maximum pressure limit
(e) all properties of liquid and steam are same.
this is the maximum pressure limit
38
Water boils when its vapour pressure
(a) equals that of the surroundings
(b) equals 760 mm of mercury
(c) equals to atmospheric pressure
(d) equals the pressure of water in t he container
(e) boiling has "nothing to do with vapour pressure.
equals that of the surroundings
39
40
Mechanical equivalent of heat for 1 kcal or Joule's equivalent is equal to
(a) 421 kgm
( b) 421 kgm
(c) 539 kgm
(d) 102 kgm
(e) 75 kgm .
421 kgm
41
Equiva lent evaporation of water is the evaporation "for a feed water supply at 100°C
(a) and its corresponding conversion into dry saturated steam at 100C and 1.033 kg/cm2
(b) and its corresponding conversion into dry steam at desired boiler pressure
(c) conversion into steam at atmospheric condition
{d) conversion into steam at t he same pressure at which feed water is supplied
{e) none of the above.
and its corresponding conversion into dry saturated steam at 100C and 1.033 kg/cm2
42
The increase in pressure
(a) lowers the boiling point of a liqu id
(b) raises the boiling point of a liquid
(c) .does not affect the boiling point of a liquid
(d) reduces its volume
(e) none of the above.
raises the boiling point of a liquid
43
The evaporation of 15.653 kg of water per hour from and at toooc is called
(a) evaporative capacity
{b) factor of evaporation
(c) equivalent evaporation
(d) one boiler h.p.
(e) boiler efficiency.
one boiler h.p.
44
During polytropic process
(a) heat transfer takes place across cylinder walls
(b) work is done
(c) steam may be wet, dry or superheated after expansion
(d) all of the above
(e) none of the above.
all of the above
45
Hygrometery deals with the
(a) Hygroscopic substances
(b) water vapour in air
(c) temperature of air
(d) pressure of air
(e) density measurement.
water vapour in air
46
Orsat meter is used for
(a) gravimetric analysis of the flue gases
(b) volumetric analysis of the flue gases
(c) mass flow of t he flue gases
(d) measuring smoke density of flue gases
(e) none of the above.
volumetric analysis of the flue gases
47
Alkaline pyrogaflate is used in Orsat's apparatus for absorption of
(a) C02
(b) CO
(c) 02
(d) N2
(e) none of t he above.
02
48
An ideal regenerative cycle is
(a) equal to camot cycle
(b) less than carnot cycle
(c) more than c.arnot cyde
(d) could be anything
(e) none of the above.
less than carnot cycle
49
Efficiency of rankine cycle can be increased by
(a) decreasing initial steam pressure and temperature
(b) increasing exhaust pressure
(c) decreasing exhaust pressure
(d) increasing the expansion ratio
(e) increasing number of regenerative heaters.
decreasing initial steam pressure and temperature
49
Cochran boiler is a
(a) horizontal fire-tu be boiler
(b) horizontal water-tube boiler
(c) veritcal water-tube boiler
(d) vertical fire tube boiler
(e) forced circulating boiler.
vertical fire tube boiler
50
Lancashire 'boiler is a
(a) stationary fire tube boiler
(b) stationary water t ube boiler
(c) water t ube boiler with natural/forced circulation
(d) mobile fire t ube boiler
(e) none of the above.
stationary fire tube boiler
51
Efficiency of a thermal cycle increases by
(a) regeneration
( b) reheating of steam
(c) both (a) and (b)
(d) cooling of steam
( e) none of the above.
both (a) and (b)
52
One kilowatt-hour energy is equivalent to
(a) 1000 J
( b) 360 kj
(c) 3600 kj
(d) 3600 kW/sec
( e ) 1000 kl.
3600 kj
53
Which of the following gases has the highest calorific value
(a) producer gas
(b) coal gas.
(c) water gas
(d) blast furnace gas
(e) coke oven gas.
coal gas.
54
100% efficiency of a thermal cycle cannot be: achieved because of
(a) frictional losses
(b) it is not possible to achieve 0K temperature
(c) leakage
(d) non-availability of ideal substance
(e) none of the above.
it is not possible to achieve 0K temperature
55
For burning 1 kg of carbon to CO as per chemically correct combustion, amount of air required is
(a) 1 kg
(b) 4/ 3kg
(c) 8/3kg
(d) 2 kg
(e) 16/3 kg.
4/ 3kg
55
Steam engine operates on
(a) carnot cycle
(b) joule cycle
(c) Stirling cycle
(d) brayton cycle
(e) none of t he above.
brayton cycle
55
The diameter of Cornish boiler is of the order of
(a) 1-2 m
(b) 1.5-2.5 m
(c) 2-3 m
(d) 2.5-3.5 m
(e) 0.5 to 1 m .
1-2 m
55
The change in internal energy in steam engines equals to
(a) work done during the rankine cycle
(b) work done during compression.
(c) work done during adiabatic expansion
(d) change in enthalpy
(e) none of the above.
work done during the rankine cycle
56
The length of Cornish boiler is of the order of
(a) 2-4m
( b) 3-5 m
(c) 5-7.5 m
(d) 7-9 m
(e)9-11 m .
5-7.5 m
56
The diameter of fire tube of Cornish boiler compared to its shell is
(a) one half
(b) one third
(c) one-fifth
(d) two-fifth
(e) three-fifth.
one half
57
Water tube boilers are those in which
(a) flue gases pass through tubes and water around it
(b) water passes through the tubes and flue gases around it
(c) work is done during adiabatic expansion
(d) change in enthalpy
( e) none of the above.
work is done during adiabatic expansion
58
Locomotive type boiler is
(a) horizontal multi-tubular water tube boiler
( b) water wall enclosed furnace type
(c) vertical tubular fire tube type
(d) horizontal multi-tubular fire tube type
( e) none of the above types.
horizontal multi-tubular fire tube type
59
Lancashire boiler is of
(a) stationary< fire tube-type
( b) horizontal type
(c) natural circulation type
(d) internally fired type
( e) all of the above.
all of the above.
60
Which of t he following substance will have same percentage in both proximate and ultimate analysis
(a) ash
( b) volatile matter
(c) moisture
(d) hydrogen
(e) none of t he above.
ash
60
Fire tube boilers are those in which
(a) flue gases pass through tubes and water around it
( b) water passes through the tubes and flue gases around it
(c) forced circulation takes place
(d) tubes are laid vertically
( e) none of the above.
flue gases pass through tubes and water around it
61
The number of flue tubes in Lancashire boiler is
(a) zero
(b) one
(c) two
(d) four
(e) many.
two
61
Which of t he following is a fire tube boiler
(a) locomotive boiler
(b) Babcock and Wilcox boiler
(c) Stirling boiler.
(d) all of the above
(e) none of the above.
locomotive boiler
62
Which of t he following is a water tube boiler
(a) locomotive boiler
(b) Cochran boiler
(c) Cornish boiler
(d) Babcock and Wilcox boiler
(e) Lancashire boiler.
Babcock and Wilcox boiler
62
The diameter of cylindrical shell of t he Lancashire boiler is of the order of
(a) 1 to 1.25m
( b) 1 to 1.75 m
(c)2 to 4m
(d) 1.75 to 2.75 m
(e) 2.25 to 4.5 m.
1.75 to 2.75 m
63
A packaged boiler is one in which various parts like firing equipment, fans, feed pumps and automatic controls are
(a) supplied by same manufacturer loose and assembled at site
(b) supplied mounted on a single base
(c) purchased from several parties and packed together at site
(d) packaged boiler does not exist
(e) none of the above.
supplied mounted on a single base
64
The biggest size of thermal power unit operating in India is
(a) 30 MW
(b) 60 MW
(c) 100 MW
(d) 210 MW
(e) 500 MW.
500 MW.
65
The high pressure boiler is oiie producing steam at a pressure more than
(a) atmospheric pressure
(b) 5 kg/cm2
(c) 10 kg/cm2
(d) 40 kg/cm2
( e) 75-80 kg/cm2.
75-80 kg/cm2.
66
Which of the following coal is has the highest calorific value
(a) anthracite coal
(b) bituminous coal
(c) lignite
(d) peat
(e) wood .
anthracite coal
67
The crown of the fire box is made hemispherical in order to
(a) give maximum space
( b) give maximum strength
(c) withstand pressure inside boiler ,
(d) resist intense heat in fire box
( e) enable easy, manufacture.
resist intense heat in fire box
67
Which of the following is steam dbal
(a) non-coking bituminous coal
(b) brown coal
(c) pulverised coal
(d) coking bituminous coal
( e) none of the above.
non-coking bituminous coal
68
The fire tubes in, a Coarran and Scotish marine boiler are
(a) horizontal
( b) vertical
(c) inclined
(d) both horizontal and vertical
( e) horizontal and inclined.
horizontal
68
The diameter of internal flue tubes in a Lancashire boiler compared to its shell is
(a) one-half
( b) one-third
(c) one-fourth
(d) one-fifth
(e) two-fifth.
two-fifth.
69
The basic purpose of drum in boiler is to
(a) serve as storage of steam
(b) serve as storage of feed water for water wall
(c) remove salts from water
(d) separate steam from water
(e) control level
separate steam from water
69
Duplex feed pumps are used in small steam boilers. These operate on the principle of
(a) centrifugal pump
(b) axial flow pump
(c) gear pump
(d) ejector pump
(e) reciprocating pump.
reciprocating pump.
70
The best suited coal for chain or travelling grate stoker boiler is
(a) coking coal
(b) non coking or free burning coal
(c) pulverised coal
(d) high sulphur coal
(e) least ash content coal.
non coking or free burning coal
71
In natural circulate ion type boiler,
(a) 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
(b) water is supplied in durm and through down-comers located in atmospheric conditon it passes to th~ water wall and
rises to drum in the form of mixture of water and steam
(c) feed pump is employed to supp ent natural drculation in wat er wall typ~ furnac~
(d) water is converted into steam in one . pass without any recirculation
( e) water is fed at atmospheric pressure.
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
71
Hard coke is produced by carborisation of coal at
(a) atmospheric temperature
( b) 5oo-6oo*c
(c) 700-850°C
(d) 950-1100*c
(e) 1200-1500°C.
950-1100*c
72
Hard coke is used in
(a) cement industry
( b) therma l power plant
(c) blast furnace
(d) domestic use
(e) locomotives
blast furnace
73
Pick: up the correct statem~nt a s regards Cornish boiler and Lancashir~ boiler
(a) cornish is fire tube and lancashire is water tube
(b) cornish i s water t ube and lanca sh ire is fire tube
(c) cornish has two fire tubes and la ncashire has on~
(d) lancashire has two fire tubes and cornish has one
(e) both have two fire t ubes.
lancashire has two fire tubes and cornish has one
74
I n locomotive boiler, maximum steam pressure is limited to
(a) 1 kg/cm2
(b) 5 kg/cm2
(c) 10 kg/cm2
(d) 18 kg/cm2
(e) 31 kg/cm2.
18 kg/cm2
75
Locomotive boiler is of the following type
(a) multitubu lar
(b) horizontal
(c) internally fired
(d) mobi le
( e) all of the above.
all of the above.
76
The shell diameter and length of locomotive boiler are
(a) 1.5 m, 4m
(b) 1.5 m, 6 m
(c) 1m, 4 m
(d)2m,4m
(e) 1.5 m, 8 m.
1.5 m, 4m
77
The diameters of fire tubes and su perheaer tubes in locomotive boiler are
(a) 47.5 mm, 130 mm
( b) 32.5 mm, 180 mm
(c) 65.5 mm, 210 mm
(d) 24.5 mm, 65 mm
47.5 mm, 130 mm
77
The water tubes in a babcock and wilcox boiler are
(a) horizontal
(b) vertical
(c) inclined
(d) horizontal and inclined
(e) vertical and inclined.
inclined
77
Which of t he following varieties of coals is mostly used in steam boilers
(a) non-coking bituminou s coal
(b) brown coal
(c) peat
(d) coking bituminous coal
(e) none of the above.
none of the above.
78
The diameter of tubes for natural circulation boiler as compared to controlled circulation boilers is
(a) more
( b) less
(c) same
(d) could be more or less depending on other factors
(e) none of the above.
more
78
A boi ler in India should conform to safety regulations of
(a) DIN
( b) BS
(c) ASTM
(d) IBR
(e) GOST.
IBR
79
The function of injector used in small steam plants is to
(a) create vacuum in Furnace
(b) create vacuum at tu rbine exhaust
(c) pump feed water
(d) dose chemicals in feed water
(e) control steam temperature by injecting water.
pump feed water
80
Which of t he following boilers is best suited to meet fluctuating demands
(a) babcock and wilcox
(b) locomotive
(c) lancashire
(d) cochran
(e) cornish.
locomotive
81
The difference between cornish boiler and lancashire boiler is that
(a) former is fire tube type and latter is water tube type boiler
( b) former is water tube type and latter is fire tube type
(c) former contains one fire tu be and latter contains two fire tubes
(e) none/of the above.
former contains one fire tu be and latter contains two fire tubes
82
I n accelerated circulation type boiler
(a) heating takes place at bottom and t he water supplied at bottom gets converted into the mixture of stdam bubbles and
hot water which rise to durm
( b) water is supplied in drum and through downcomers" located in atmospheric conditon it passes to the water wall and
rises to dunn in the from of mixture of water and steam
(c) feed pump is employed to su pplement natural drculat ion in wat er wall type furnace
(e) water is converted into steam in one pass without any recirculation
(e) water is fed under high pressure and high velocity .
water is supplied in drum and through downcomers" located in atmospheric conditon it passes to the water wall and
rises to dunn in the from of mixture of water and steam
83
Pick up the wrong statement about water t u be boiler in comparison to fire tube boilers
(a) former generates steam at high pressure
(b) former occupies less space for same power
(c) rate of steam flow is more in former case
(d) former is used for high installed capacity
(e) chances of explosion are less in former case.
chances of explosion are less in former case.
84
The number of drums in Benson steam generator is
(a) one
(b) two
(c) one steam drum and one water drum
(d) no drum
(e) none of the above.
no drum
85
A fusible plug is fitted in small boilers in ord er to
(a) avoid excessive build up of pressure
(b) avoid explosion
(c) extinguish fire if water level in th e boiler falls below alarming limit
(d) control steam dome
( e) remove molten aslj.
extinguish fire if water level in th e boiler falls below alarming limit
85
The fusible plug in small boilers is located
(a) in the drum
( b) in the fire tubes
(c) above steam dome
(d) over the combustion chamber
( e) at the inlet of chimney.
over the combustion chamber
85
Boiler H.P. is defined as t he
(a) steam evaporation rate per kg of fuel fired
( b) wort< done in evaporat ing 1 kg of steam per hour from and at 100°C into dry saturated steam
(c) the evaporation of 15.65 kg of water per hour from and at 100oc into dry saturated steam
(d) wort< done by 1 kg of steam at saturation condition
( e) heat consumed in evaporating 1 kg water .at 0°C to steam at 100°C and 1.033 kg/em pressu re.
the evaporation of 15.65 kg of water per hour from and at 100oc into dry saturated steam
85
Fusible plug for boilers is made of fu sible meta l containing tin, lead, and
(a) bismuth
( b) copper
(c) aluminium
(d) nickel
( e) iron.
bismuth
86
I n forced recircu lation type boiler,
(a) heat ing takes place at bottom and t he water supplied at bottom g ets converted into the mixture of steam bubbles and
h ot water which rise to drum
(b) 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
(c) feed pump is employed to su pplement natural circulation in water wall t ype furnace
(d) water is converted into steam in one pass without any recirculation
( e) heat ing of water takes place in stages.
feed pump is employed to su pplement natural circulation in water wall t ype furnace
87
The ratio of heat utilised to produce steam and t he heat liberated in furnace is known as
(a) boiler effectiveness
( b) boiler evaporative capacity
(c) factor of evaporation
(d) equivalent evaporation
(e) boiler efficiency.
boiler efficiency.
88
Thermal efficiency of a t hermal power plant is of the order of
(a) 15%
( b) 20%
(c) 30%
(d) 45%
( e ) 60% .
30%
88
Which type of boiler c.an meet rapid changes of load
(a) vertical fire tube type
( b) horizontal fire t ube type
(c) horizontal water tube type
(d) vertical water t ube type
(e) forced circulation type
forced circulation type
88
Steam in water t ube boiler as compared to fire tube boiler
(a) can be ra ised ra pidly
(b) is raisd at slower rate
(c) is raised at same rate
(d) could be raised at fast/slow rate depending on d esign
( e) none of the above is true.
can be ra ised ra pidly
88
Boiler stays are used to
(a) prevent flat su rfaces under pres.sure from tearing apart
( b) take care of failure in shear
(c) take care of failure in compression
(d) provide support for boiler
( e) provide foundation of boiler.
prevent flat su rfaces under pres.sure from tearing apart
88
It is required to produce large amount of steam at low pressure. Wh ich boiler should be used?
(a) pulverised fuel fired boiler
( b) cochran boiler
(c) lancashire boiler
(d) babcock and wi lcox boiler
(e) stoker fired boiler.
lancashire boiler
88
The overall efficiency of t herma l power plant is
(a) boiler efficiency, t urhine efficiecny, generat-or efficiency
(b) all t he three above plus gas cycle efficiency
(c) carnot cyde efficiency
(d) regenerative cycle efficiency
(e) rankine cycle efficiency.
boiler efficiency, t urhine efficiecny, generat-or efficiency
88
Thermal efficiency of well mainta ined boiler will be of the order
(a) 20%
( b) 40%
(c) SO%
(d) 75%
( e) 90% .
90%
88
I n forced circulation type boiler
(a) heat ing takes place at bottom and t he water supplied at bottom g ets converted into the mixture of steam bubbles and
h ot water which rise to drum
( b) water is supplied in drum and through down-comers located in atmospheric condition it passes to the water wall and
rises t o drum in the form of mixture of water and steam
(c) feed pump is employed to su pplement natural circulation in wat er wall type furnace
(d) water is converted into steam in one pass without any recirculation
( e) water is heated in a large n umber of t ubes.
water is converted into steam in one pass without any recirculation
89
The major axis of elliptical manholes on the shell should be provided
(a) longitudinally
( b) circumferentially
(c) on di shed end
(d) anywhere
( e) vertically.
circumferentially
89
Size of boiler tubes is specified by
(a) mean diameter and t hicknes.s
( b) inside diameter and thickness
(c) outside diameter and thickness
(d) outside diameter and inside diameter
( e) outside diameter alone.
outside diameter and thickness
89
I n which of the following boilers, t he draught in furnace is increased by utilising exhaust steam from engine
(a) lancashire boiler
( b) locomotive boiler
(c) babcock and wi lcox boiler
(d) cochran boiler
( e) benson boiler.
locomotive boiler
89
The heat loss in a boiler takes place in t he form of
(a) heat carried away by Hue gases
( b) heat carried away by ash
(c) moisture present in fuel and steam formed by combustion of hydrogen in fuel
(d) radiation
( e) all of the above.
all of the above
89
The radius of a dish ed head is taken approximately as
(a) one -fourth
( b) half
(c) one
(d) two
( e) t hree.
one
89
With increase in load, radiant superheater has
(a) drooping characterist ic
( b) lihear characterisstic
(c) rising characteristic
(d) flat characteristic
( e) none of the above.
drooping characterist ic
90
The pressure of reheat steam after passing through reheater compared to inlet condition is
(a) more
(b) less
(c) equal
(d) may be more or less depending on capacity of reheater
( e) none of the above.
less
90
The safety valve at superheater as compared to drum safety valve setting is set at
(a) higher value
( b) lower value
(c) same value
(d) any value
(e) none of t he above.
lower value
90
The function of injector used in small capacity boilers is to
(a) create vacuum
( b) inject chemic.al solution in feed pump
(c) pump water similar to boiler feed pump
(d) add make up water in t he system
( e) none of the above.
pump water similar to boiler feed pump
90
I n designing air preheater, t he importa nt design consideration is that
(a) approach temperature should be as low as possible
(b) handling and maintenance should be easier
(c) heat transfer area should be optimum
(d) stack gases should not be cooled to t he dew point
(e) none of the above.
stack gases should not be cooled to t he dew point
91
I n regenerative air preheater, the heat is transferred
(a) from a metal wall from one medium to another
(b) from heating an intermediatea naterial and then heating t he air from this material
(c) by direct mixing
(d) heat is tra nsferred by bleeding some gas frQm furnace
(e) none of the above.
from heating an intermediatea naterial and then heating t he air from this material
92
The height of chimney in a power plant is governed by
(a) the draft to be created
(b) limitation of construction facilities
(c) control of pollution
(d) quantity of flue gases to be handled
(e) all of the above.
control of pollution
93
Steam exhaust from high pressure turbine is reheated in
(a) boiler drum
(b) superheater tubes
(c) economiser
(d) a separate coil
( e) a separate coil located in convection path.
a separate coil located in convection path
93
Vacuum for reciprocating steam engines co mpared to steam turbines is
(a) more
( b) equal
(c) less
(d) could be more or less depending on t he size of plant
( e) none of the above.
less
94
Expanding steam to a very low prseeure (high vacuum) in steam engines is
(a) desirable
( b) economical
(c) essential
(d) optional
( e) uneconomical.
uneconomical.
95
I n locomotives, the draught is produced by
(a) chimney
( b) induced draft fan
(c) both combined (a) and (b)
(d) steam jet draught
( e) none of the above.
steam jet draught
96
Reheating of steam under ideal conditions ta kes place at constant
(a) entropy
( b) enthaply
(c) pressure
( d) temperat ure
(e) all of the above.
all of the above.
97
The maximum discharg ~ through a chimn~y occurs when th~ height of chimn~y is
(a) infinitely long
( b) around 200 meters
(c) equal to t he height of t he hot gas column producing draught
(d) outside temperat ure is very low
(e) more than the tallest building nearby.
equal to t he height of t he hot gas column producing draught
98
Proximate analysis of fuel is determination o f percentage of
(a) carbon, hydrogen, nitrogen, sulph ur, moisture
(b) fixed carbon, ash, volatile matter, moisture
(c) higher calorific value
(d) lower calorific value
(e) rough analysis.
fixed carbon, ash, volatile matter, moisture
99
Which device is used in t hennal power plants to reduce level of pollution
(a) induced draft fan
(b) smoke meter
(c) chimney
(d) precipitator
(e) pulveriser.
precipitator
100
Bomb calorimeter is used to d etermine
(a) Higher calorific value at constant volume
(b) Lower calorific value at constant volum~,
(c) Higher calorific value at constant pressure
(d) Lower calorific valu~ at constant pr~ssure
( e) None of the above.
Higher calorific value at constant volume
101
Ultimate analysis of fuel is d etermination of percentage of
(a) carbon, hydrogen, itrog~n, sulph ur, moisture
( b) fixed carbon, ash, volat ile matter, moisture
(c) higher calorific value
(b) lower calorific value
( e) best analysis.
carbon, hydrogen, nitrogen, sulph ur, moisture
102
For combut:sion of a fuel, following is es.sential
(a) correct fuel air ratio
( b) proper ignition temperature
(c) 02 to support combustion
(d) all t he three above
(e) none of the above.
all t he three above
102
Spontaneous combustion is a phenomenon in which
(a) all t he fuel burns instantaneously producing high energy release
(b) fuel burns with less air
(c) coal bursts into flame without any external ignition source but by itself due to gradual increase in temperature as a
result of heat released by combination of oxygen with coal
(d) explosion in furnace
( e) none of the above.
coal bursts into flame without any external ignition source but by itself due to gradual increase in temperature as a
result of heat released by combination of oxygen with coal
103
The economiser is used in boilers to
(a) increase t hermal efficiency of boil~r
( b) economise on fuel
(c) extract heat from h~ exhaust flue gases
(d) increase flue gas temperature
( e) to heat feed water by bled steam.
increase t hermal efficiency of boil~r
104
An economiser in a boiler
(a) increases steam pressure
( b) increases steam flow
(c) decreases fuel consumption
(d) decreases steam pressure
(e) increases l ife of boiler.
decreases fuel consumption
105
02 content in atmospheric air on volum~ basis is
(a) 21%
(b) 23%
(d) 30%
(d) 40%
(e) 70%.
21%
105
02 content in atmospheric air on weight basis is
(a) 21%
(b) 23%
(c) 30%
(d) 40%
(e) 70%.
23%
106
Primary air is t he air used to
(a) provide air around burners for obtaining optimum combustion
(b) transport and dry the coal
{c) convert CO (formed in lower zone of furnace) into C02 at higher zone
(d) air-delivered by forced draft fan
(e) none ot t he above.
transport and dry the coal
107
Sulphur content of fuels is very im portant t-o t he plant operators because it
{a) has high heating value
(b) retards electric precipitation
(c) promotes complete combustion
(d) has highly corrosive effect
{ e) facilitates ash removal.
has highly corrosive effect
108
Presence of moisture in fuel oi l would
(a) keep t he burner ti ps cool
(b) aid in proper combustion
{c) cause sputtering, possibly extinguish-,ing flame
(d) clean the nozzl es
( e) reduce flame length .
cause sputtering, possibly extinguish-,ing flame
109
Gusset stays in a boiler are provided to
(a) prevent the bulging of flat surfaces
( b) avoid explosion in furnace
(c) prevent lea kage of hot flue gases
(d) support furnace freely from top
{ e) prevent atmospheric a ir leaking into furnac~.
prevent the bulging of flat surfaces
109
Water and sediment in fuel oil can be removed by
{a) heat ing the oil in t he settling tanks
{ b) cooling t he oil in the settling tanks
{c) burning the oil
{d) suspension
( e) filtering .
heat ing the oil in t he settling tanks
110
Pour point of fuel oil is t he
{a) lowest temperature at which oil will flow under set condition
{ b) storage temperatu re
{c) temperature at w hich fuel is pumped through burners
{d) temperature at w hich oil is transported
{e) none of the above.
lowest temperature at which oil will flow under set condition
111
Secondary air i s the used to
{a) provide a ir around burners for obta ining optimum combustion
(b) transport and dry the coal
(c) convert CO (formed in lower zone of furnat>!) into C02 at higher zone
{d) air d elive red by induced draft fan
{ e) air fed to pulverisers.
provide a ir around burners for obta ining optimum combustion
112
The behaviou r of coal in a furnace is determained by
{a) the content of sulphur
{ b) the content of ash and heating value
{c) the pro>cimate a nalysis
{d) the e>cact analysis
( e) itstype.
the pro>cimate a nalysis
113
Pick up wrong statement about desired properties of a good fuel
{a) high calorific value
{ b) produce m inimum smoke and gases
{c) ease in storing
(d) high ignition point
{ e) ecomomica l
high ignition point
113
Sulphur in coal results in
{a) causing cli nkering and stagging
{ b) corroding air heaters
{c) spontaneous combustion during coal storage
{d) facilitating ash predpitation
(e) all of t he above.
all of t he above.
113
Green coal, in order to be burn ~ must be
(a) heated sufficiently
(b) burnt in excess air
{c) heated to its ignition point
(d) burnt as powder
{e) burnt as lumps.
heated to its ignition point
113
The ultimate analysis of fuel lists
{a) various chemic.al constituents, carbon, hydrogen~ oxygen etc, plus ash as per-cents by volume
(b) various chemical constituents, carbon, hydrogen, oxygen, etc, plus ash as per-cents by weight
{c) fuel constituents as percents by volume of moisture, volatile, fixed carbon and ash
{d) fuel constituents a s percents by weight of moisture, volatile, fixed carbon and ash
{e) moisture and ash free heating value.
various chemical constituents, carbon, hydrogen, oxygen, etc, plus ash as per-cents by weight
113
The proximate analysis of fuel lists
{a) various chemic.al constituents, carbon, hydrogen, oxygen etc, plus ash as per-cents by volume
(b) various chemical constituents, carbon, hydrogen, oxygen, etc, plus ash as per-cents by weight
{c) fuel constituents as percents by volume of moisture, volatile, fixed carbon and ash
{d) fuel constituents a s percents by weight of moisture, volatile, fixed carbon and ash
{ e) moisture and ash free heat ing value.
fuel constituents a s percents by weight of moisture, volatile, fixed carbon and ash
113
Caking coals are those w hich
{a) form lumps or masses of coke
(b) burn freely
{c) show little or no fusing action
(d) burn completely
(e) do not form ash.
form lumps or masses of coke
114
With increase in load, convection superheater has
(a) drooping characterist ic
( b) linear characterisstic
(c) rising characteristic
(d) flat characteristic
(c) none of the above.
rising characteristic
114
The temperature of flue gases at air heater outlet should be
(a) 1oo*c
( b) above dew-point temperature of flue gases
(c) below d ew-point temperature of flue gases
(d) less than wet bulb temperature of flue gases
(e) above wet bulb temperature of flue gases.
above dew-point temperature of flue gases
115
The diameter of fire tubes in Cochran boiler is of the ord er of
(a) 2 em
( b) 6Cm,
(C) 8 em
(d) 12 em
( e ) 15 em.
6Cm,
116
A safety valve in a locomotive starts leaking. The leaking medium will be
(a) water
( b) dry stea m
(c) wet steam
( d) super heated steam
(e) su persaturated stea m.
super heated steam
116
I n a recuperative air preheater, t he heat is tra nsferred
(a) from a metal wall from one medium to another
( b) from heating an itermediate material and t h en heating the air from this material
(c) by direct mixing
(d) heat is tra nsferred by bleeding some gases from furnace
( e) none of the above.
from a metal wall from one medium to another
117
Tertiary air is the air used to
{a) provide air around burners for obta ining optimum combustion
(b) transport and dry the coal
{c) cool the sc.anners
{d) supply air for ignitors
{ e) convert CO {formed in lower zone of furnace) into C02 at higher zone.
convert CO {formed in lower zone of furnace) into C02 at higher zone.
117
The safety valve on boiler drum compared to safety valve on superheater i s set at
{a) same value
( b) higher value
{c) lower value
{d) lower/higher depending on steam flow
( e) unpredicatble.
higher value
118
Which is not correct statement about pul ~rised fuel firing
{a) high burning rate is possible
{ b) heat release can be easily controlled
{c) fuel burns economically
{d) it is the best technique for burning high ash content fuel having low fusion ash
{ e) separate mills are required to powder t he ooal.
it is the best technique for burning high ash content fuel having low fusion ash
119
The three "Ts"' for good combust ion are
{a) temperature, t ime, and turbulance
{ b) total air, true fuel, and t urbulance
{c) thorough mixing, total air, and temperature
{d) total air, t ime, and temperature
{e) none of the above.
temperature, t ime, and turbulance
120
Which is not correct statement about t he funct ion of furnace
{a) to provide proper conditions for con-tinuous complete combustion
(b) mix fuel with air and ignite
(c) separate ash from coal
{d) maintain heat supply to prepare and ignite the incoming fuel
{ e) to minimise radiation losses.
separate ash from coal
121
Which is not correct statement about effect of sulphur in f uel
{a) it has heating value
{ b) it helps in electrostatic precipitation of ash i n flue-gases
{c) it leads to corrosion of air heaters, ducting, etc. if flue gas exit temperature is low
{d) it erodes furnace walls
{ e) none of the above.
it erodes furnace walls
121
Heating value of fuel used is as on fired basis. If it is reported for dry or moisture free fuel, then latter should be
multiplied by the following factor to correct for as fired value
(a) ( 1- moisture content)
(b) ( 1 +moisture content)
{c) 1 + moisture content
{d) 1 - moisture content
( 1- moisture content)
122
Ga rdually increasi ng temperature of flue gases at inlet to chimney for given steam outputs is an indication of
{a) higher effectiveness of boiler
{ b) high calorific value coal being burnt
{c) fouling of heat transfer surfaces
{d) raising of steam temperature
(e) lea kage of air.
fouling of heat transfer surfaces
123
I ncomplete combustion c.an be best j udged by
{a) smoky chimney exit
(b) excess air in flue gases
{c) measuring carbon mono-oxide in flue gases
{d) measuring temperat ure of flue gases at exit of furnace
{e) measuring oxygen in fl ue gases.
measuring carbon mono-oxide in flue gases
124
The capacity of induced draft fan compared to forced draft fan in a boiler is
(a) same
(b) more
(c) less
{d) less or more depending on size of boiler
(e) unpredictable.
more
125
Pu lverised fuel is used for
{a) better burning
(b) more calorific value
{c) less radiation loss
{d) medium sized units
{e) stoker fired boilers.
better burning
126
Calorific value of coal is of the order of
(a) 200-400 kcal/kg
(b) 800-1200 kcal/kg
(c) 2000-4000 kcal/kg
(d) 5000-8000 kcal/ kg
(e) 8000-10,000 kcal/kg.
2000-4000 kcal/kg
126
Eva porat ive c.apacity of boiler is expres.sed as
(a) kg of steam produced
(b) steam pressure produced
(c) kg of fuel fired
(d) kg of steam produced per kg of fuel fifed
{e) kg of water evaporated.
kg of steam produced per kg of fuel fifed
127
Boiler parameters are expressed by
{a) tonnesjhr. of steam
{b) pressure of steam in kg/cm2
{c) temperature of steam in oc (d) all of the above
{e) none of the above.
all of the above
128
The condition of steam in boiler drum is always
(a) dry
(b) wet
{c) saturated
{d) supersat urated
(e) su perheated .
wet
129
In ordetjo obtain superheated steam, a superheater i s added in an existing boiler. As as result, furnace vacuum will
{a) remain unaffected
(b) improve
(c) worsen
(d) may improve/worsen depending on size
(e) unpredictable.
worsen
129
Maximum energy loss in a boiler occurs due to
{a) unburnt c.arbon in ash
(b) incomplete combustion
{c) ash content
(d) flue gases
{e) radiation losses.
flue gases
129
The balanced draft furnace is one using
{a) induced draft fan and chimney
(b) induced draft fan and forced draft fan
{c) forced draft fan and chimney
(d) any one of the above
{e) none of the above.
induced draft fan and forced draft fan
130
Overfire burning is t he phenomenon of
{a) supply of excess, air
(b) supply of excess coal
{c) burning CO and unbumts in upper zone of f urnace by supplying more air
(d) fuel bed firing
{e) none of the above.
burning CO and unbumts in upper zone of f urnace by supplying more air
131
Which is not the correct statement about moisture in coal
{a) inherent moisture and surface mois-,ture are different things
{b) in some coals moisture may be present upto 40%
{c) some m oisture in coal helps in better burning which is not possible with completely dry coal
{d) it increases t hermal efficiency
{e) moisture in coal is removed before firing by heating it with hot air.
it increases t hermal efficiency
132
Oeaeration of feed water is carried out because it reduces
{a) cavitation of .boiler feed pu mps
{b) corrosion caused by oxygen
{c) heat transfer coefficient
(d) pH value of water
(e) weight of water to be handled.
corrosion caused by oxygen
133
A supercritical boiler is one t hat operates above t he pressure and temperature o f following values
(a) 100 kg/cm2 and 540°C
(b) 1 kg/cm2 and 1oo*c
(c) 218 kg/cm2 abs and 373°C
(d) 218 kg/cm2 abs and 540°C
(e) 100 kg/cm2 abs and 373°C
218 kg/cm2 abs and 373°C
134
Natural water circulation, by convect ion in water tube boilers, w ith increase in pressure of boiler
{a) increases
(b) decreases
(c) remains unaffe-cte-d
(d) first increases and t hen decreases
(e) first decreases and then increases.
decreases
135
The steam temperature with increase in load in case of a boiler fitted with radiation superheater
(a) increases
( b) decreases
(c) remains unaffe-cte-d
(d) first increases and t hen decreases
(e) unpredictable.
decreases
136
During storage, the he-ating value- of coal
(a) increases
(b) decreases
(c) remains constant
(d) may increase or decrease depending upon t he met hod of storage
(e) none of the above.
decreases
136
The relative heat absorption for successively added equal areas of boiler convection heating surfaces
(a) increases
(b) decreases
(c) remains unaffected
(d) first increases and t hen decreases
(e) first decreases and then increases.
decreases
137
Film boling occurs at
(a) very low pressure
(b) atmospheric pressures
(c) medium pressu res
(d) very high pressures
( e) none of the above.
very high pressures
138
Fire tube boilers are limited to a maximum design working pressure of
(a) 1 kg/em
( b) 6 kg/em
(c) 17 kg/cm2
(d) 100 kg/cm2
( e) 250 kg/cm2.
17 kg/cm2
139
For the same diameter and thickness of t ube, a water t ube boiler compared to a fire tube boiler has
(a) more heating surface-
( b) less heating surface
(c) equal heating surface
(d) heating surface depends on other parameters
(e) none of the above.
more heating surface-
140
I n water wall furnace, t he heat is tran sferred to the water-walls by
(a) convection
(b) radiation
(c) conduction
(d) radiation and conducton
(e) radiation and convection.
radiation
140
Relative percentage of heat absorbed through the heat transfer of
( i) furnace water wall,
( ii) boiler bank,
( Hi) superheaters
( iv) economiser,
(v) airheater of a typical boiler of 200 MW capacity would be of the order of
(a) 48:20:15:7:10
(b) 10:7:15:20:48
(c) 20:48:7:15:10
(d) 7:15:20:10:48
( e) 48:15:10:7:20.
48:20:15:7:10
141
The feed check valve is used in order to
(a) regulate flow of boiler water
(b) check level of water in boiler drum
(c) recirculate unwanted feed water
(d) allow high pressure fee-d water to flow to drum and not allow reverse flow to take place
( e) none of the above.
allow high pressure fee-d water to flow to drum and not allow reverse flow to take place
142
The size of a boiler drum in pulverised fuel fired boiler,as its size and capacity, (steam pressure and flow ratings)
increase
(a) increases
(b) decreases
(c) remains unchanged
(d) increases/decreases depending on stea m temperature requirements
(e) unpredictable.
decreases
143
Feed water conditioning in t herma l power p lants in done to
(a) reduce hardness and for removal of solids
(b) increase efficiency-of t hermal power plant
(c) increase *heat transfer rate
(d) increase steam parameters
(e) all of the above.
reduce hardness and for removal of solids
144
The basic job of feed water treatment in bo ilers is to overcome the problem of
( a) corrosion
(b) scale
{ c) carryover
( d ) embrittlement
(e) all of the above.
all of the above.
