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

Determine the correctness or otherwise of the following Assertion [a] and the Reason [r]. Assertion [a]: In a power plant working on a Ranking cycle, the regenerative feed water heating improves the efficiency of the steam turbine. Reason [r]: The regenerative feed water heating raises the average temperature of heat addition in the Rankine cycle.

A

Both [a] and [r] are true and [r] is the correct reason for [a].

B

Both [a] and [r] are true but [r] is NOT the correct reason for [a].

C

Both [a] and [r] are false

D

[a] is false and [r] is true.

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

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

A thermal power plant operates on a regenerative cycle with a single open feedwater heater, as shown in the figure. For the state points shown the specific enthalpies are : h1 = 2800 kJ/kg and h2 = 200 kJ/kg. The bleed to the feedwater heater is 20% of the boiler steam generation rate. The specific enthalpy at state 3 is

A

720 kJ/kg

B

2280 kJ/kg

C

1500 kJ/kg

D

3000 kJ/kg

What are the effects of regenerative feedwater heating for the same turbine output? 1. It significantly increases the cycle efficiency and reduces the heat rate. 2. It increases the steam flow rate. 3. It increases the steam flow to the condenser. 4. If there is no change of boiler output, the turbine output drops. Select the correct answer using the code given below:

A

1, 2 and 3 only

B

1, 2 and 4 only

C

1, 3 and 4 only

D

2, 3 and 4 only

Consider the following statements: 1. The air standard efficiency of an Otto cycle is a function of the properties of the working substance (gas) 2. For the same compression ratio and same input, the thermal efficiency of an Otto cycle is more than that of a Diesel cycle 3. Thermal efficiency of a Diesel cycle increases with decrease of cut-off ratio Which of the above statements are correct?

A

1 and 2 only

B

1 and 3 only

C

2 and 3 only

D

1, 2 and 3

Which of the following statements are correct with respect to regenerative feed heating in a steam cycle? 1. It increases cycle efficiency 2. It increases specific output 3. It reduces the condenser load 4. It improves the steam quality at the end of expansion

A

1 and 3 only

B

2 and 4 only

C

2 and 3 only

D

1,2,3 and 4

If Stirling cycle with regenerative arrangement and Carnot cycle operate within same temperature limits, then the thermal efficiency of Carnot cycle will be ___________

A

same

B

half

C

twice

D

none of the mentioned

The efficiency of an ideal regenerative cycle is ____ the Carnot cycle efficiency.

A

greater than

B

equal to

C

less than

D

none of the mentioned

The efficiency of regenerative cycle will be ____ the efficiency of the Rankine cycle.

A

greater than

B

equal to

C

less than

D

none of the mentioned

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

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