An economiser is installed in a boiler primarily to

The function of an economiser in a boiler is to preheat the

A

Feedwater

B

Combustion air

C

Pulverised coal

D

Furnace oil

An economiser _________ the steam raising capacity of a boiler.

A

Increases

B

Decreases

C

Has no effect on

D

None of these

An economiser in a boiler

A

Increases steam pressure

B

Increases steam flow

C

Decreases fuel consumption

D

Decreases steam pressure

What is the effect on the performance of the economiser in the thermal power plant boiler, if the feed water temperature is very low due to preheaters being out for repairs or starving of steam supply ?

A

It results in corrosion due to the condensation on the flue gas side of the economiser tubes due to handling of low temperature water

B

Economiser tube life increases due to handling of low temperature water

C

Heat transfer efficiency of economiser increases due to picking up high heat from the flue gases

D

Scale formation rate on economiser tubes increases

Use of economiser in a boiler plant reduces the fuel consumption for steam generation by about __________ percent.

A

1

B

10

C

30

D

45

A _________ in a boiler is used to put off fire in the furnace of the boiler when the level of water in the boiler falls to an unsafe limit.

A

Blow off cock

B

Fusible plug

C

Stop valve

D

Safety valve

Economiser is used to heat

A

air

B

feed water

C

flue gases

D

all above

An economiser is generally placed between

A

Last superheater or reheater and air preheater

B

Induced draft fan and forced draft fan

C

Air preheater and chimney

D

None of the above

The economiser is used in boilers to

A

Increase thermal efficiency of boiler

B

Economize on fuel

C

Extract heat from the exhaust flue gases

D

Increase flue gas temperature

A valve installed between the boiler and the feed pump is

A

Blow off cock

B

Feed check valve

C

Steam stop valve

D

None of these

An economiser is installed in a boiler primarily to

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