Repeat Problem, but now add an air-preheat section to the steam generator in the Rankine c...

Repeat Problem, but now add an air-preheat section to the steam generator in the Rankine cycle, such that the air to be used in the combustion process is heated to 400 K by the gases exiting the combustion process. This will involve increasing the required heat load in the steam generator to include the heating of the air.

Problem

Design a combustion process (specifying the fuel, equivalence ratio, and product exit temperature) to provide the heat required by the modified Rankine cycle described in Example. Based on current fuel prices, estimate the daily cost of the fuel for the cycle. Assume the fuel and air enter at 25°C.

Example