A regenerative steam power cycle with two feedwater heaters, one closed and one open, as shown in the figure. Steam enters the first stage of the turbine at 12 MPa, 480°C and expands to 2 MPa. Some steam is withdrawn at 2 MPa and fed to the closed feedwater heater. The remainder expands through the second stage turbine at 0.3 MPa, where an additional amount is drawn off and fed to the open feedwater heater operating at 0.3 MPa. Steam expanding through the third-stage turbine leaves at a condenser pressure of 6 kPa. The feedwater leaves the closed heater at 210°C, 12 MPa, and the condensate leaving as a saturated liquid at 2 MPa is trapped in the open feedwater heater. Saturated liquid at 0.3 MPa leaves the open feedwater heater. Assume that all stages of the pumps and turbines operate isentropically. Determine for the cycle: (a) The heat transfer to the working fluid passing through the steam generator, in kJ per kg of steam entering the first-stage turbine. (b) thermal efficiency. (c) the heat transfer from the working fluid passing through the condenser to the cooling water, in kJ per kg of steam entering the first-stage turbine.
A regenerative steam power cycle with two feedwater heaters, one closed and one open, as shown in the figure. Steam enters the first stage of the turbine at 12 MPa, 480°C and expands to 2 MPa. Some steam is withdrawn at 2 MPa and fed to the closed feedwater heater. The remainder expands through the second stage turbine at 0.3 MPa, where an additional amount is drawn off and fed to the open feedwater heater operating at 0.3 MPa. Steam expanding through the third-stage turbine leaves at a condenser pressure of 6 kPa.
The feedwater leaves the closed heater at 210°C, 12 MPa, and the condensate leaving as a saturated liquid at 2 MPa is trapped in the open feedwater heater. Saturated liquid at 0.3 MPa leaves the open feedwater heater. Assume that all stages of the pumps and turbines operate isentropically. Determine for the cycle:
(a) The heat transfer to the working fluid passing through the steam generator, in kJ per kg of steam entering the first-stage turbine.
(b) thermal efficiency.
(c) the heat transfer from the working fluid passing through the condenser to the cooling water, in kJ per kg of steam entering the first-stage turbine.
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