Homework-3-solutions

# Homework-3-solutions - 1! ! MEM 415 Fuel Cell Engines...

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1 Dr. E. C. Kumbur | MEM " 415 Fuel Cell Engines MEM 415 Fuel Cell Engines HOMEWORK SET#3 Couple of Notes: - You can submit this homework with one other person if you wish , or you can submit it by yourself. It is all up to you. - If you need some values, you can refer the Table 3.2 and 3.3 in your text book. - You can also use the thermo tables given in the Appendix section of your fuel cell text book . - Please state your assumptions (if any) clearly in your solution. - You can use correlations for constant specific heats given in your text book (Pg. 73, Eqs (3.24) to (3.29)) Questions 1) (10%) For a 1 kmol mixture of 20% H2, 30% H2Ov, and 50% CO2 by volume, determine a) the mixture molecular weight and b) enthalpy at 350 K. (Hint: Look up the values from Table A-9) 2) (10%) Determine the change in enthalpy and entropy for a stoichiometric (balanced) hydrogen-air redox reaction with the hydrogen and oxygen reactants and products at 1000 C. You can assume constant specific heats, but you need to evaluate the values though.

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2 Dr. E. C. Kumbur | MEM " 415 Fuel Cell Engines H 2 +1/2 O 2 –- H 2 O Here, the specific heats were calculated at 650 C (average temperature) 3) (15%) Consider a stationary hydrogen-air PEFC. Since hydrogen is not directly available, the fuel cell at 353K is to be fed by reformed natural gas. That is, natural gas will be chemically converted into a mixture of hydrogen and other nonreactive components. This gas mixture will be fed into the anode
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## This note was uploaded on 04/26/2011 for the course MEM 415 taught by Professor Kumbur,emin during the Spring '11 term at Drexel.

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Homework-3-solutions - 1! ! MEM 415 Fuel Cell Engines...

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