Solve the following exercise on paper, scan your manuscript and upload the solution as directed by the application.
A coal fired power plant boiler B consumes coal with heating value H = 30MJ/kg, at a rate of thy = 4kg/sec, while 20MW of heat is
expelled by the boiler as heat losses and hot gases from the chimney. The boiler is producing superheated steam at pressure P3-5MPa (50bar) and
temperature T3-400°C. The steam is then lead to a turbine T operating with isentropic efficiency of 90% and an outlet pressure of 50KPa (0.5bar). The
depleted steam is condensed to saturated liquid water at the condenser C which is then fed to a pump. The pressure of the saturated water is raised
back to the operating high pressure by the pump P which operates isentropically (isentropic efficiency of 100%). For your analysis, use the steam tables
provided evaluating at the closest values shown in the tables.
Qbz
mH,
B
tw₂
T
Wt
Qc
Considering that all other processes correspond to an ideal operation of a Rankine Cycle, address the following:
i) Sketch the cycle on the T-s diagram provided. (10-marks)
ii) Calculate the mass flow rate of the steam produced by the boiler. (10-marks)
ii) Find the specific work and the mechanical power produced by the turbine. (10 marks)
iv) Calculate the overall plant efficiency. (5 marks)
v) Calculate the quality of the steam at the turbine exit. (5-marks)
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