Use the reaction data in Problems P11-4A and P12-7B for the case when heat is removed by a heat exchanger jacketing the reactor. The flow rate of coolant through the jacket is sufficiently high that the ambient exchanger temperature is constant at T_a = 50°C. A+B → C
(a)

(1) Plot and then analyze the temperature conversion, Qr, and Q_g profiles for a PBR with where Uaρb=0.08Js⋅kg-cat⋅K where
ρb = bulk density of the catalyst (kg/m³)
a = heat-exchange area per unit volume of reactor (m²/m³)
U = overall heat transfer coefficient (J/s · m² · K)
(2) How would the profiles change if Ua/=_b were increased by a factor of 3000?
(3) If there is a pressure drop with α = 0.019 kg^–1?
(b) Repeat part (a) for co-current and countercurrent flow and adiabatic operation with m˙c=0.2 kg/s, CPc = 5000 J/kg K and an entering coolant temperature of 50°C.
(c) Find X and T for a “fluidized” CSTR with 80 kg of catalyst. UA=500Js⋅K,ρb=1 kg/m³
(d) Repeat parts (a) and (b) for W = 80.0 kg, assuming a reversible reaction with a reverse specific reaction rate of kr=0.2 exp[ErR(1450−1T)](dm6kg-cat⋅mol⋅s);Er=51.4 kJ/mol

Vary the entering temperature, T₀, and describe what you find.
(e) Use or modify the data in this problem to suggest another question or calculation. Explain why your question requires either critical thinking or creative thinking. See
Preface Section G and http://www.umich.edu/~scps.

Data from Problems P11-4A

The elementary, irreversible, organic liquid-phase reaction A + B → C is carried out adiabatically in a flow reactor. An equal molar feed in A and B enters at 27°C, and the volumetric flow rate is 2 dm³/s and C_A0 = 0.1 kmol/m³.
Additional information:

PFR
a. Plot and then analyze the conversion and temperature as a function of PFR volume up to where X = 0.85. Describe the trends.
b. What is the maximum inlet temperature one could have so that the boiling point of the liquid (550 K) would not be exceeded even for complete conversion?
c. Plot the heat that must be removed along the reactor (Q˙ vs. V) to maintain isothermal operation.
d. Plot and then analyze the conversion and temperature profiles up to a PFR reactor volume of 10 dm³ for the case when the reaction is reversible with K_C = 10  m³/kmol at 450 K. Plot the equilibrium conversion profile. How are the trends different than part (a)?

CSTR
e. What is the CSTR volume necessary to achieve 90% conversion?

BR
f. The reaction is next carried out in a 25 dm3 batch reactor charged with NA0 = 10 moles. Plot the number of moles of A, NA, the conversion, and the temperature as a function of time.

Data from Problems P12-7B

Use the data in Problem P11-4A for the following reaction. The elementary, irreversible, organic liquid-phase reaction
A + B → C is carried out in a flow reactor. An equal molar feed in A and B enters at 27°C, and the volumetric flow rate is 2 dm3/s and C_A0 = 0.1 kmol/m³.
Additional information:
(a) Calculate the conversion when the reaction is carried out adiabatically in one 500-dm³ CSTR and then compare the results with the two adiabatic 250-dm³ CSTRs in series.
The reversible reaction is now carried out in a PFR with a heat exchanger. Plot and then analyze X, X_e, T, T_a, Q_r, Q_g, and the rate, –r_A, for
the following cases:
(b) Constant heat-exchanger temperature T_a
(c) Co-current heat exchanger T_a.
(d) Countercurrent heat exchanger T_a.

Transcribed Image Text:

HAO(273K)* =-20 kcal/mol,HBO(273x K)-15 kcal/mol,HCo(273K) =-41[x] kcal/mol CPC=30x cal/mol Kk-0.01dm3mol-s[x] at 300 K CPA=CPB=15cal/mol Kix E =10,000 cal/mol