QUESTION 3 (Analysis of steam cycles) 3.1 A steam power plant is proposed to operate between the pressures of 10 kPa and 2 MPa with a maximum temperature of 400°C. (a) Draw the T-s diagram. (b) Taking the pump work into consideration, determine the maximum efficiency possible from the power cycle. 3.2 If the boiler pressure in 3.1 is increased to 4 MPa while maintaining the maximum temperature and minimum pressure, neglecting the pump work, calculate the percentage increase in the thermal efficiency. 3.3 If the boiler temperature in 3.1 is increased to 600°C while maintaining the boiler pressure and condenser pressure, neglecting the pump work, determine the percentage increase in the thermal efficiency. 3.4 If the condenser pressure in 3.1 is decreased to 4 kPa while maintaining the boiler pressure and maximum temperature, neglecting the pump work, calculate the percentage increase in the thermal efficiency. 3.5 The high-temperature situation in 3.3 is to be modified by inserting an open feedwater heater (see the diagram below) such that the extraction pressure is 200 kPa. (a) Draw the T-s diagram (b) Neglecting the pump work, determine the percentage increase in the thermal efficiency. Boiler Feedwa ритр Open foodwater hase Condensa ритр Turbine Condenser ④