Question

Which one of the following combinations gives the highest conversion for second order reaction?

(a) PFR followed by smaller CSTR followed by a bigger CSTR

(b) PFR followed by bigger CSTR followed by a bigger CSTR

(c) Smaller CSTR followed by PFR followed by a bigger CSTR

(d) Bigger CSTR followed by a PFR followed by smaller CSTR

Answer 1

Correct answer is (a) PFR followed by smaller CSTR followed by a bigger CSTR

To explain I would say: For reactions of order greater than one, higher conversion is achieved in a PFR. Smaller the volume of a CSTR, it tends to behave as a PFR. Hence, for higher conversions, the reactors are arranged in the order PFR followed by smaller CSTR followed by a bigger CSTR.