?Hot nitrogen gas at 400°C and atmospheric pressure flows into a waste-heat boiler at

Chapter 6, Problem 6.79

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Hot nitrogen gas at 400°C and atmospheric pressure flows into a waste-heat boiler at the rate of \(20 kg \cdot s^{−1}\), and transfers heat to water boiling at 101.33 kPa. The water feed to the boiler is saturated liquid at 101.33 kPa, and it leaves the boiler as superheated steam at 101.33 kPa and 150°C. If the nitrogen is cooled to 170°C and if heat is lost to the surroundings at a rate of 80 kJ for each kilogram of steam generated, what is the steam-generation rate? If the surroundings are at 25°C, what is \(\dot S_{G}\) for the process? Assume nitrogen to be an ideal gas for which \(C_{P} = (7/2)R\).

Text Transcription:

20 kg cdot s^−1

S_G

C_P = (7/2)R