Power Plant - Regeneration 1

[Bernardo257]

A power plant, like the one in the figure, operates with a pressure in the boiler of 5 MPa and the steam enters the first stage of the turbine at 400 oC and leaves at a pressure of 1 MPa. Between the first and the second stage the steam is reheated to 400 oC. During the second stage of the turbine, steam is extracted at 400 kPa to an open water heater. The pressure in the condenser is 10 kPa. Consider the isentropic pumps and the turbine with an 80% isentropic efficiency. What is the steam flow required to generate 5 MW of energy in this plant and what is its thermal efficiency. Make a study of the efficiency variation as a function of the condenser pressure with the values of 20, 30, 40 and 50 kPa.

Ps: oC = degrees Celsius



Can someone please help me w this question?
Thanks a lot!

 

[MJCronin]

At University, we all had to do our own HOMEWORK....

We think that you should too ....

MJCronin
Sr. Process Engineer

 

[EdStainless]

Set up the equations, set boundary conditions, enter some estimates, and then re-calculate (relax) until they converge.
In reality the problem with plants like this is that they only really operate at one load. Between the backpressure on the turbine and the open FWH there is little way to turn these down. But at design they can be very efficient.

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P.E. Metallurgy, consulting work welcomed