Question

2. In the 1960s the catalytic oxidation of ammonia was studied in a lab fluidized-bedreactor. Experiments established the reaction as of first- order and dependent solely on the ammonia concentration

without affecting the volumetric flow rate of the feed to-the reactor. The height of the bed was 60 cm. In one experiment, the feed's volumentric flowrate was 818 cm3/s at a 523 K and 1.11 atm while 4 kg of catalyst were fluidised. The resulting experimental conversion of the ammonia reactant was22%. v_{0}=818 \mathrm{~cm}^{3} / \mathrm{s} D_{r}(\text { diameter of reactor })=11.4 \mathrm{~cm} u_{m f}=1.48 \mathrm{~cm} / \mathrm{s} d_{p}=0.105 \mathrm{~mm} \alpha=0.4 \epsilon_{m f}=0.657 d_{b}=4.87 \mathrm{~cm} -r_{A}=k C_{N H_{3}}\left(\frac{g m o l \text { of } N H_{3}}{s \cdot c m^{3} \text { of catalyst }}\right) k=0.0858 \mathrm{~s}^{-1} \text { at reaction temperature and pressure } \rho_{g}(\text { fluid density })=7.85 \times 10^{-4} \frac{g}{c m^{3}} \rho_{c}(\text { catalyst density })=2.06 \times 10^{-4} \frac{g}{\mathrm{~cm}^{3}} \mathcal{D}_{A B}=0.618 \frac{\mathrm{cm}^{2}}{\mathrm{~s}} \delta(\text { fraction of bed in the bubble phase })=\frac{u_{0}-u_{m f}}{u_{b}-u_{m f}(1+\alpha)} What is the conversion if the (theoretical) Kunii-Levenspiel model was used? ) Make a suggestion for improving performance in terms of the theoretical conversion (X) of the same fluidized bed reactor as in question a) of this section, by changing one parameter of the reactor's geometry (i.e dimensions)and keeping the remaining data the same as in question a) of this section.

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