Thermal Power Engineering Answers

A steam power plant working on ideal rankine cycle has condenser exit pressure 40 kPa. The temperature and pressure of water after passing through pump is found to be 60^oC and 5,000 kPa respectively. Analyze the effect of changing boiler temperature on thermal efficiency of plant for the following exit steam temperatures of the boiler. 

a) Steam temperature 600^oC 

b) Steam temperature 450^oC

Conclude your answer with the help of T-s diagram

Exhaust steam from a turbine enters a condenser with a specific enthalpy of 2164 kJ/kg and a velocity of 75 m/s. During the cooling process, the heat loss to the cooling water per kg of working fluid is 1680 kJ/kg. The condensate exits the system with a velocity of 12 m/s. Sketch a systems diagram for the condenser and determine the specific enthalpy of the working fluid at exit from the condenser. 

Propane gas is to be burned in a furnace at the rate of 1000 LPH at STP, using 15% 

excess air. For achieving energy efficient operation, preheated air at 100 C is to be used. 

Assume that the ambient air completely dry and at 1 atm absolute pressure is available at 

10oC. Calculate the energy required for heating the air (in kJ/h) from 10C to 100oC.