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CHE502: REACTION ENGINEERING 1

TUTORIAL 5

CHAPTER 5

[1] A liquid reactant stream (1 M) passes through two mixed flow reactors in a series. The

concentration of A in the exit of the first reactor is 0.5M. Identify the concentration in theexit stream of the second reactor, given that the reaction is second order with respect to A

and V2/V1=2.

[2] 10 L/min of liquid feed containing 1 mol A/L is to be treated to 99% conversion using two

units of CSTR. The stoichiometry and kinetics of the reaction:

  → ,  − =

 

.+  /.  

Suggest a good arrangement of the reactors (series/parallel) for the reaction above.

Identify the size of the two units needed.

[3] The adiabatic exothermic irreversible gas phase reaction below is to be carried out in a

flow reactor for a stoichiometric feed of A and B

0.5 ↔ 2 

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a.  Calculate the PFR volume needed to achieve 50% conversion?

 b.  Calculate the CSTR volume needed to achieve 50% conversion?

c.  Calculate the volume of CSTR that must be added to achieve 80% conversion

compared to part (b).

[4] An elementary gas phase reaction (isothermal, isobaric) below was carried out in a series

of reactors consisting 2 CSTR and 1 PFR where the sequencing is CSTR-PFR-CSTR.

2 → 2 

Initially, pure A was fed at molar flow rate of 50 kmol.hr. Experimental data obtained

were tabulated in the following table.

X -r A (kmol/m3.h)

0 39

0.2 53

0.4 59

0.6 38

0.65 25

a.  Construct complete stoichiometric table for the reaction above.

 b.  Calculate volume of the reactors in m3 

c.  If the arrangement is to be changed in the sequence of PFR-CSTR-PFR, identify

the volume of the reactors.

d.  For the same desired conversion of 65%, suggest which arrangement is preferred

 based on your answers in part (b) and (c).

[5] A series of reactors is suggested for the production of B, which follows equation; 

  →  

If the reaction is a first order and the feed rate is 0.867 mol/s, determine the volume

of the reactors arranged in a sequence of CSTR-PFR. Given that the conversion of the

first reactor is 50% and the overall conversion, Xfinal is 70%. Use the data provided below to assist your calculations.

X 0 0.1 0.2 0.4 0.6 0.8

-r A(mol/L.s)

0.0053 0.0052 0.005 0.004 0.0025 0.00125

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[6]   ↔  

Equal molar of liquid A and B reacts in a CSTR to produce C as shown above,

reversibly. Liquid is fed to the reactor at concentration of 5 mol/dm3. The equilibrium

constant for above reaction is 8 mol2/m3. Calculate the equilibrium conversion for each

compornent. Assume that the reaction took place in a constant volume reactor.