As shown in Fig. P13.9D, a gaseous fuel of the form CaHb

Chapter 13, Problem 13.9D

(choose chapter or problem)

As shown in Fig. P13.9D, a gaseous fuel of the form \(\mathrm{C}_{a} \mathrm{H}_{b}\) enters a well-insulated reactor at \(25^{\circ} \mathrm{C}\), 1 atm and reacts completely with the theoretical amount of air also entering at \(25^{\circ} \mathrm{C}\), 1 atm. Products of combustion exit at \(T_{P}\), 1 atm. Ignoring the effects of motion and gravity, evaluate the exergy destruction within the reactor, in kJ per kmol of fuel, for \(\mathrm{H}_{2} \mathrm{CH}_{4}, \mathrm{C}_{2} \mathrm{H}_{6}, \mathrm{C}_{3} \mathrm{H}_{8}, \mathrm{C}_{4} \mathrm{H}_{10} \text { and } \mathrm{C}_{5} \mathrm{H}_{12}\). Basing exergy values on the environment of Table A-26 (Model II), determine in each case the percentage of the fuel exergy destroyed upon combustion. Plot the percentages versus b, the number of hydrogen atoms per molecule, and interpret the plot. In a memorandum summarize findings and conclusions.