Gas-phase catalytic hydrogenation is used to convert o-cresol to 2-methylcyclohexanone (used in fragrances) over a Ni-on-silica...

 

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Gas-phase catalytic hydrogenation is used to convert o-cresol to 2-methylcyclohexanone (used in fragrances) over a Ni-on-silica catalyst at 170 C in an isothermal packed bed reactor: OH & CH3 CH3 2H2 -> The reaction is zero order in o-cresol and first order in hydrogen pressure; the reactor is operated under the following conditions: k = 0.05 mol cresol/(kg cat min atm) inlet flow = 40 mol/min, 67% H2 and 33% o-cresol, 10 atm a) Neglecting the pressure drop due to the catalyst pellets in the PBR, determine X vs. catalyst weight (W) and plot the pressure profiles of all the species down the reactor (i.e., wrt W). b) Repeat part (a) for the case when the pressure drop is not neglected. Use the Ergun equation with alpha = 0.135 atm*kg where alpha is as defined in class (note: Fogler's alpha is slightly different, and it is only valid for one given initial P). How is this situation different from (a)? What does this tell you about maximizing conversion in a real reactor situation? c) Referencing part (b), what is the PBR pressure drop if we use W=40 kg of catalyst? How do the part (a) and (b) conversions compare for W=40 kg? Gas-phase catalytic hydrogenation is used to convert o-cresol to 2-methylcyclohexanone (used in fragrances) over a Ni-on-silica catalyst at 170 C in an isothermal packed bed reactor: OH & CH3 CH3 2H2 -> The reaction is zero order in o-cresol and first order in hydrogen pressure; the reactor is operated under the following conditions: k = 0.05 mol cresol/(kg cat min atm) inlet flow = 40 mol/min, 67% H2 and 33% o-cresol, 10 atm a) Neglecting the pressure drop due to the catalyst pellets in the PBR, determine X vs. catalyst weight (W) and plot the pressure profiles of all the species down the reactor (i.e., wrt W). b) Repeat part (a) for the case when the pressure drop is not neglected. Use the Ergun equation with alpha = 0.135 atm*kg where alpha is as defined in class (note: Fogler's alpha is slightly different, and it is only valid for one given initial P). How is this situation different from (a)? What does this tell you about maximizing conversion in a real reactor situation? c) Referencing part (b), what is the PBR pressure drop if we use W=40 kg of catalyst? How do the part (a) and (b) conversions compare for W=40 kg?