The irreversible first-order (wrt partial pressure of A) gas-phase reaction A → B is carried out isothermally in a “fluidized” catalytic CSTR containing 50 kg of catalyst. Currently, 50% conversion is realized for pure A entering at a pressure of 20 atm. There is virtually no pressure drop in the CSTR. It is proposed to put a PBR containing the same catalyst weight in series with the CSTR. The pressure drop parameter for the PBR, α, α = 0.018 kg–1. The particle size is 0.2 mm, the bed porosity is 40%, and the viscosity is the same as that of air at 200°C.

a. Should the PBR be placed upstream or downstream of the CSTR in order to achieve the highest conversion?

b. What is the conversion coming out of the first reactor?

c. What is the conversion exiting the last reactor?

d. What is the pressure at the exit of the packed bed?

e. How would your answers change if the catalyst diameter were decreased by a factor of 2 and the PBR diameter were increased by 50%, assuming turbulent flow?

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