What is the expression for enthalpy of each heater hper heater if a represents the enthalpy of heated feedwater from the economiser and b represents the enthalpy at condenser & n represents the number of heaters?

In a newly developed innovative idea brought up by CSIR in India, gas turbine exhaust gas are being utilized to convert feedwater into steam. Certain data of the experiment are as follows: mass flow rate of exhaust gas = 40 kg/hr, enthalpy of exhaust gas at the time of their exit from gas turbine is 600 kJ/kg, steam turbine output as measured by brake dynamometer = 60 hp-sec, thermal efficiency of steam power plant is 0.25, efficiency of exhaust gas in converting feedwater into steam is taken as 50%. Find the enthalpy of exhaust gas remaining after they generate steam from feedwater?

A

350.0KJ/Kg

B

241.2KJ/Kg

C

112.45KJ/Kg

D

512.56KJ/Kg

A regenerative feedwater heating cycle with an infinite number of feedwater heaters has efficiency equal to?

A

Brayton cycle

B

Carnot cycle

C

Diesel cycle

D

Otto cycle

Read the following statements about feed water heaters I. Open or contact heaters are also called Deaerator. II. Open or contact heaters constructed to remove non-condensable gases from feed water.

A

Only statement I. is correct

B

Only statement II. is correct

C

I. and II. are correct

D

I. and II. are wrong

The expression for temperature rise t in feedwater heater when a & b are the temperatures of boiler saturation & condenser respectively, is given by which of the following expression?

A

t = 0.5 (a x

B

[ t = 0.5 (a / [

C

t = 0.5 (a + b)

D

t = 0.5 (a – b)

The temperature rise from condenser to boiler saturation is divided __________ among the feedwater heaters for maximum gain in efficiency.

A

unequally

B

partially

C

equally

D

remains undivided

Which of the following statements about vertical tube economiser (Green’s economiser) is FALSE?

A

It is used with boilers operating below 25 bars

B

It is an integral type economiser

C

The direction of flow of flue gases is opposite to that of water

D

It consists of a blow-off cock for removal of sediments

If heater S is used on the third day and different heaters are used on the first and fourth days, then which heater is used on the first day?

A

P

B

Q

C

R

D

S

What happens to the feedwater that enters the economiser?

A

Feedwater is heated to the saturation temperature at the boiler pressure

B

Feedwater is heated to the boiler temperature at the saturation pressure

C

Feedwater is cooled to the saturation temperature

D

Feedwater is cooled at the boiler pressure

The feedwater in the Economiser _________

A

is heated by bled turbine steam

B

is cooled by bled turbine steam

C

is heated by outgoing flue gases

D

is cooled by outgoing flue gases

Land masses are heated and cooled much faster than water bodies. Identify the true statements in this regard:
I. Land gets heated by conduction
II. Water has higher specific heat
III. Only the surface layers of water are heated
IV. Water gets heated by convection

A

I, II and III

B

II and III

C

I and IV

D

I, II and IV

What is the expression for enthalpy of each heater hper heater if a represents the enthalpy of heated feedwater from the economiser and b represents the enthalpy at condenser & n represents the number of heaters?

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