POWER PLANT ENGG MCQ PART 4

                                                                        

77.    The efficiency of a modern boiler using coal and heat recovery equipment is about

(a) 25 to 30%
(b) 40 to 50%
(c) 65 to 70%
(d) 85 to 90%

Ans: d

 

78.    The average ash content in Indian co als is about

(a) 5%
(b) 10%
(c) 15%
(d) 20%

Ans: d

 

79.    Load centre in a power station is

(a)    centre of coal fields
(b)    centre of maximum load of equipments
(c)    centre of gravity of electrical system

Ans: c

 

80.    Steam pressure in a steam power station, which is usually kept now-a-days is of the order of

(a) 20 kgf/cm2
(b) 50 kgf/cm2
(c) 100 kgf/cm2
(d) 150 kgf/cm2

Ans: d

 

81.    Economizers improve boiler efficiency by

(a) 1 to 5%
(b) 4 to 10%
(c) 10 to 12%

Ans: b

                                 

82.    The capacity of large turbo-generators varies from

(a) 20 to 100 MW
(b) 50 to 300 MW
(c) 70 to 400 MW
(d) 100 to 650 MW

Ans: b

 

83.    Caking coals are those which

(a)     burn completely
(b)     burn freely
(c)    do not form ash
(d)    form lumps or masses of coke

Ans: d

 

84.    Primary air is that air which is used to

(a)     reduce the flame length
(b)     increase the flame length
(c)    transport and dry the coal
(d)    provide air around burners for getting optimum combustion

Ans: c

 

85.    Secondary air is the air used to

(a) reduce the flame length
(b) increase the flame length
(c) transport and dry the coal
(d) provide air round the burners for getting optimum combustion

Ans: d

 

86.    In coal preparation plant, magnetic separators are used to remove

(a) dust
(b) clinkers
(c) iron particles
(d) sand

Ans: c

 

87.    Load carrying capacity of belt conveyor is about

(a)     20 to 40 tonnes/hr
(b)     50 to 100 tonnes/hr
(c)    100 to 150 tonnes/hr
(d)    150 to 200 tonnes/hr

Ans: b

 

88.    Method which is commonly applied for unloading the coal for small power plant is

(a) lift trucks
(b) coal accelerators
(c) tower cranes
(d) belt conveyor

Ans: b

                                 

89.    Bucket elevators are used for

(a)    carrying coal in horizontal direction
(b)    carrying coal in vertical direction
(c)     carrying coal in any direction

Ans: b

 

90.    The amount of air which is supplied for complete combustion is called

(a) primary air
(b) secondary air
(c) tertiary air

Ans: b

 

91.    In ______ system fuel from a central pulverizing unit is delivered to a

bunker and then to the various burners

(a) unit
(b) central
(c) none of the above

Ans: b

92.    Compounding of steam turbine is done for

(a)    reducing the work done
(b)    increasing the rotor speed
(c)    reducing the rotor speed
(d)    balancing the turbine

Ans: c