Question

QUESTION 2: Design of Multiple Reactors: 30 marks B +C was a a) An elementary reaction A reaction A B +C was carried out in a reactor system using an ideal STR followed by an ideal PER Isothermany. The rate constant is k = 0.4 min ". The volumetric flow rate is 20 L/min. The concentration of A in the feed is 5 moles/L. 1. Calculate the volume of the CSTR necessary to achieve a conversion of 50%. (7 marks) What is the final conversion achieved, if the volume of the PFR is 30L? (8 marks) b) Levenspiel plots are constructed for the same homogeneous reaction carried out in isothermal operation (solid line) and in adiabatic operation (dotted line with symbols) and shown in Figure 1 below. We would like to go for continuous production using a CSTR and/or a PFR i) What is the difference between isothermal operation and adiabatic operation? (2marks) Recommend the type of a single continuous reactor to reach a conversion of 40%, if the system must remain isothermal and you wish to minimize reactor volume. Determine its volume. (6 marks) ill) For adiabatic operation, recommend the type of a single continuous reactor to reach a conversion of 50%, if you wish to minimize reactor volume. Determine its volume. (3 marks) iv) If you like to get a conversion of 70%, recommend the type of additional reactor needed and determine its volume for adiabatic operation, if you make use of the reactor in c) until 50% conversion by adiabatic operation. (4 marks)

Answer 1

Quo 2 A - BIC TARCA. To reactor (STR followed by PER. Given, K= Da min! rate (v). 2000 m volumetric flow - 20 Yan. (CAD - 5 moy Initial concentration equation for CSTR, To performance G : Y 5.co k. Co (1-XA) Mo - Jux (05) CSTR require is 502. volume of takes place in (STR, D) 50% since, СА conversion (1-) но 0.5x5 = .25 move. Given, CA = 25 NOL, - 01 -XA) 30 20.125) Kcho. – en li-xa) 30 x014 I XA = 0.45118. - * - lado - Cams -> Cap = 1.372

Now, overall conversion, x = - C = -372 - 07256 11372 overall conversion is 12561 while conversion in Pready is 45121 For part (b). Figure require where isothermal operation and adiabatic Operation plot is constructed.