A regenerative Rankine cycle uses three closed feedwater preheaters. Using the stream numbering from Fig. 5.5, and the specified conditions below, the plant capacity is to be 80 MW. Other constraints are as follows: The efficiency of each turbine stage is 88%; the pump efficiency is 80%; and the feedwater leaving each preheater is 5°C below the temperature of the condensate draining from the bottom of each preheater. For the options below, calculate:

(a) The flowrate of stream 1

(b) The thermal efficiency of the plant

(c) The size of the feedwater pump (kW)

Options:

Transcribed Image Text:

(i) The conditions are T = 700C, P = 4 MPa, P = 1 MPa, P3 = 0.3 MPa, P4= 0.075 MPa, and P = 0.01 MPa. (ii) The conditions are T = 750C, P = 4.5 MPa, P = 1.2 MPa, P3 = 0.4 MPa, P = 0.05 MPa, and P, = 0.01 MPa.