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Dehydrogenation of Ethanol

Consider the heterogeneously catalyzed reaction:

EthanolAcetaldehyde+H2\text{Ethanol} \rightarrow \text{Acetaldehyde} + \mathrm{H}_{2}

The first-order (surface) reaction rate coefficient is kr=0.45 m s1k_{r} = 0.45~\mathrm{m~s^{-1}}. The (zero flux) binary mass-transfer coefficients are: k12=0.07 m s1k_{12} = 0.07~\mathrm{m~s^{-1}}, k13=0.23 m s1k_{13} = 0.23~\mathrm{m~s^{-1}}, and k23=0.23 m s1k_{23} = 0.23~\mathrm{m~s^{-1}}. These values are given at the operating conditions p=1.0105 Pap = 1.0 \cdot 10^{5}~\mathrm{Pa} and T=548 KT = 548~\mathrm{K}. The bulk gas phase composition is:
x1=0.60x_{1} = 0.60, x2=0.20x_{2} = 0.20, x3=0.20x_{3} = 0.20.

Assume ideal gases and that a film model is appropriate.

Questions:

  1. Write down the Maxwell-Stefan equations.

  2. Solve this system by direct numerical integration. What are the molar fluxes?

  3. Solve this system using the exact “matrix method.”

  4. Make a linear approximation of the concentration profiles and solve the resulting algebraic equations.

  5. Solve this system using the approximate “matrix method” in a mass-average reference frame.

  6. Compare the accuracy of the different methods.

Note that all numerical implementations should be consistent with the provided equations and parameter values.