In regenerative cycle the heat of flue gases is used to heat the feed water. So practically not all of heat of flue gas can be given to feed water, which is aim of Regenerative cycle. Therefore ideally all heat should be given to feed water coming into turbine and thus maximum heat transfer will occur till the water temperature difference becomes zero (between feed water and flue gas temperature)

Answer:

Introduction:
The regenerative cycle is a thermodynamic cycle used in steam power plants to increase the efficiency of the power generation process. In this cycle, the steam that leaves the turbine is partially extracted and used to heat the feedwater before it enters the boiler.

The Temperature of Steam Entering the Turbine:
The correct answer to the given question is option 'B': Water leaving the turbine. In an ideal regenerative cycle, the temperature of the steam entering the turbine is the same as the temperature of the water leaving the turbine.

Explanation:
To understand why the temperature of the water leaving the turbine is the same as the temperature of the steam entering the turbine, let's go through the steps of the regenerative cycle:

1. Boiler: The feedwater enters the boiler and is heated to its saturation temperature, where it is converted into steam.

2. Turbine: The high-pressure steam from the boiler enters the turbine and expands, producing mechanical work. As the steam expands, its temperature and pressure decrease.

3. Steam Extraction: In a regenerative cycle, some of the steam leaving the turbine is extracted before it reaches the condenser. This extracted steam is sent to a heat exchanger, where it transfers heat to the feedwater.

4. Feedwater Heating: The extracted steam gives up its heat to the feedwater in the heat exchanger, increasing the temperature of the feedwater.

5. Turbine Reheating: After the feedwater is heated, it is pumped back into the boiler, where it is further heated to its saturation temperature before entering the turbine again.

6. Turbine Expansion: The reheated steam from the boiler enters the turbine and expands again, producing additional mechanical work.

7. Condenser: The low-pressure steam leaving the turbine is finally condensed into water in the condenser, and this water is then pumped back into the boiler to complete the cycle.

Conclusion:
In the regenerative cycle, the temperature of the steam entering the turbine is the same as the temperature of the water leaving the turbine because the extracted steam is used to heat the feedwater, ensuring that the temperature of the feedwater matches the temperature of the steam entering the turbine. This helps in improving the overall efficiency of the power plant by reducing the amount of heat energy wasted in the condenser.