Problem 1. Non-isothermal reactor (Total: 35 Marks) The elementary, irreversible gas-phase reaction A B+C is carried out in an adiabatic catalytic packed bed reactor, which behaves as a pseudo-homogeneous PFR without

any internal or external mass transfer resistances. Pure A enters the reactor at a volumetric flow rate of 20 L/s, at a pressure of 10 atm, and a temperature of 450 K. The reaction rate constant is given by -0.133-exp(450K7 L kg a) Assuming that there is no pressure drop along the reactor, plot the conversion and temperature along the reactor packed with 50 kg catalyst and calculate the catalyst weight required for a 75% conversion. [11] Next, consider that pressure drop exists along the PFR. The Ergun equation, -G1-150(1-0)µ D₂ for varying gas density gives dP dz pgp P TOFT p=POPOT Fr dP dW = q₂T_ Po (1+x) 2 Cooling fluid: Heat capacity Inlet temperature, where a, is a parameter dependent on the system operating conditions and characteristics of the catalyst used &=2.P.RO (17) (2) (1) 150(1-0)+1.750 D₂ +1.750) (1) -5 (3) A(1-0) Ifa, = 0.0075 kg: ¹for the catalyst particles, the reactor and the conditions used b) Plot the temperature, conversion and pressure along the length of the reactor packed with 50 kg catalyst. How does reactor behaviour change as compared to a)? J s-kgk [12] A heat exchanger is added to the PFR to keep the outlet temperature at 700K, as above this temperature undesired reactions occur. For the heat exchanger Ua P₂ Cong3 J/gK Tooting 400 K. 1 Po (4) where, pe is the bulk density of the catalyst (kg/m'eactor), a is the heat-exchange area per unit volume of reactor (m²reactor/acter) and U is the overall heat-transfer coefficient (J/s-m²actar K). c) Calculate the outlet temperature of the coolant and its flowrate for co-current heat exchange, ignoring pressure drop. Plot the conversion, the temperature of the cooling fluid and the temperature of the reaction mixture as a function of catalyst weight. [12] Additional Information Activation energy: E = 31.4 kJ/mol Heat capacities: C = 40 J/mol K, Cas= 25 J/mol K, Cpc = 15 J/mol K Heats of formation at 273K: H=-70 kJ/mol, H₂= -50 kJ/mol, H = -40 kJ/mol