The gas phase reaction A + B → C follows an elementary rate law and occurs in a 1 m³ CSTR.
The inlet volumetric flow rate is 0.5 m³ min¹¹ and the entering concentration of A is 1 M. The
reaction occurs isothermally at 300K. For an equimolar feed of A and B, a 20% conversion is
achieved. When the reaction is carried out adiabatically, the exit temperature is 350K and the
conversion is 40%. The heat capacities of A, B, and C are 25, 35, and 60 kJ/(mol*K), respectively
and are independent of temperature. It is proposed to add a 2nd CSTR of the same size in series
with the first CSTR. There is a heat exchanger attached to the 2nd CSTR with UA = 4.0
kJ/(min*K), and the coolant fluid enters and exits the heat exchanger at the same temperature of
350K. Assume all reactors operate isobarically.
A. What is the rate of heat removal needed for isothermal operation in the first CSTR?
B. What is the final conversion at the exit of the second reactor if the first reactor is
operated isothermally?
C. What would the final conversion be if the second CSTR were replaced with a 1 m³ PFT
with Ua = 10(kJ/(m³*min*K)) and T₁ = 300K.
D. A chemist suggests that the reverse reaction cannot be neglected. From
thermodynamics, we know that Kc = 2 L/mol at 310K. What conversion can be achieved
if the entering temperature to the PFR in part C is 300K and Ta = 300K? You may assume
that the first CSTR achieves a conversion of 0.2 for the problem.
