Exergy Analysis of Reacting and Psychrometric SystemsConsider a furnace operating at stead...

Exergy Analysis of Reacting and Psychrometric Systems

Consider a furnace operating at steady state idealized as shown in Fig. P13.109. The fuel is methane, which enters at 25°C, 1 atm and burns completely with 200% theoretical air entering at the same temperature and pressure. The furnace delivers energy by heat transfer at an average temperature of 227°C. Combustion products at 600 K, 1 atm are provided to the surroundings for cogeneration of steam. There are no stray heat transfers, and the effects of motion and gravity can be ignored. Determine in kJ per kmol of fuel

(a) the exergy entering the furnace with the fuel.

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(b) the exergy exiting with the products.

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(c) the rate of exergy destruction.

Also, evaluate an exergetic efficiency for the furnace and comment. Perform calculations relative to the environment of Problem 13.91.

Fig. P13.109

Problem. 13.91

Using Chemical Exergy

Applying Eq. 13.36 for (a) carbon, (b) hydrogen (H2), (c) methane, (d) carbon monoxide, (e) nitrogen (N2), (f) oxygen (O2), and (g) carbon dioxide, determine the chemical exergy, in kJ/kg, relative to the following environment in which the gas phase obeys the ideal gas model:

(13.36)