Problem 3. Residence time distribution (Total: 20 Marks) Dr Doolittle carries out the liquid-phase first-order reaction A → B with reaction rate constant, k = 1h-¹, and inlet reactant concentration, CA,0

= 1 mol/m³ in a reactor cascade consisting of two CSTRs in series of equal volume, each one 1 m³ (overall cascade volume V = 2 m³). The overall reactor cascade space time is 0.67 h. Overnight her competitor, Dr Darkforce, tampers with the reactor system to lower its productivity. The morning after, Dr Doolittle observes that the reactant conversion has dropped. She gets suspicious, so she stops the reaction and performs a pulse tracer experiment, finding the following residence time distribution. E, h-¹ -1 0.64 0.5 0.4 0.3 0.2 0.1 Ө -0.1 1 2 RTD 3 t, h 4 2 6 7 8 The measured RTD is composed by a sharp peak (E₁ (t)) at t = 0 h, where the area under this peak is 0.33 (blue arrow) followed by an orange broad peak E₂. The values of E₂ (t) are reported in the table below. a) Evaluate the conversion of the reactor cascade as designed by Dr Doolittle, before Dr Darkforce's tampering. [4] b) What do you think Dr Darkforce did to the reactor cascade? Suggest a compartment model that fits quantitatively the RTD that Dr Doolittle measured and calculate the parameters of this compartment model.