Q4.A steam turbine plant producing 22 MW expands steam in two stages with reheat between the stages.
The first stage expands the steam from a pressure and temperature of 60 bar and 540°C respectively to a pressure of 5 bar, at which point, the specific entropy of the steam has increased by 2.15%.
The steam is then reheated at constant pressure to 470°C.
In the second stage, the steam expands to a condenser pressure of 0.05 bar and the specific entropy increases by 2.5%.
The feed water leaves the condenser at a temperature of 28°C.
The feed pump work cannot be ignored.
(a) Draw the expansion and reheat processes on Worksheet Q4. (4)
(b) Sketch the cycle on a Temperature-specific entropy diagram. (2)
(c) Using Worksheet Q4 determine EACH of the following:
(i) the mass flow rate of steam in tonne per hour; (5)
(ii) the specific steam consumption; (2)
(iii) the thermal efficiency of the cycle. (3)
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