Modern Engineering Thermodynamics

650 CHAPTER 15: Chemical Thermodynamics
99.* Design a combustion chamber for a rocket that will oxidize
liquid hydrazine, N 2 H 4 ðlÞ, with liquid hydrogen peroxide,
H 2 O 2 ðlÞ, at 1.00 MPa and 2000. K as follows:
N 2 H 4 ðlÞ + 2ðH 2 O 2 ðlÞÞ ! 4½H 2 OðgÞŠ + N 2 , and that will supply the
rocket nozzle with 1000. kg/s of exhaust gas. Data:ðh ° f Þ N2H4ðlÞ =
50:417 MJ/kgmole, and ðh ° f Þ H2O2ðlÞ = −187:583 MJ/kgmole:
100. Design a benchtop laboratory-scale facility to produce methanol
from the reaction CO + 2ðH 2 Þ!CH 3 ðOHÞ: Determine all flow
rates, heat transfers, reaction vessel optimum temperature and
pressure, reaction vessel material, and geometry.
Computer Problems
The following open-ended computer problems are designed to be
done on a personal computer using a spreadsheet or equation solver.
101. Develop a spreadsheet to compute the LHV of gaseous octane
and use it to find the adiabatic flame temperature for (a) 100.%
and (b) 200.% theoretical air.
102. Develop a spreadsheet to balance the combustion reaction of
any simple alcohol of the type C n H 2n+1 ðOHÞ with excess or
deficit air or oxygen.
103. Develop a spreadsheet with temperature-dependent specific
heats for a hydrocarbon fuel of your choice listed in Table 15.1
to do one or more of the following:
a. Compute the heat of reaction of the fuel when the reaction
temperature and percent of excess air or oxygen are input by
the user.
b. Compute the adiabatic flame temperature of the fuel for any
excess air or oxygen value.
104. Develop an interactive computer program that outputs the
entropy production rate for any (or a series of) reaction(s) of
your choice. Input from the keyboard is in response to properly
formatted screen prompts for the stoichiometric coefficients, the
heat of reaction, the reaction temperature and pressure, and the
isothermal heat transfer boundary temperature. Use the program
to determine
a. The maximum pressure for a given isothermal boundary
temperature at which the reaction can occur.
b. The maximum isothermal boundary temperature possible for
any given reaction pressure and temperature.
105. Develop an interactive computer program that outputs the
equilibrium constant K e when the stoichiometric coefficients are
input from the keyboard in response to properly formatted
screen prompts. Assume all the components obey the Gibbs-
Dalton ideal gas mixture law.
106. Develop an interactive computer program to replace Table C.17
for the dissociation of H 2 O, CO 2 , and NO. You have to find the
relevant information on H, O, and N in other texts if you wish
to also include the dissociation of H 2 ,O 2 , and N 2 :
107. Develop an interactive computer program that outputs the
molar specific enthalpy h i , entropy ð si Þ, and Gibbs function
ðg i Þ for any substance of your choice at any user input pressure
and temperature.
108. Develop an interactive computer program that outputs the
power and reaction efficiency of any reaction you desire. Apply
this program to a fuel cell analysis and plot the reaction
efficiency η r vs.
a. The percent of excess oxidizer present.
b. The reaction temperature.
c. The reaction pressure.
d. The entropy production rate.
e. The fuel cell heat transfer rate _Q :
Assume isothermal boundaries and input T b from the
keyboard along with all other necessary information.