1. Tutorial 4 solutions Lecturer: Miss Anis Atikah Ahmad
Tel:

2. Questions The liquid phase reaction A + B  C
follows an elementary rate law and is carried out isothermally in a flow system. The concentrations of A & B feed streams are 2 M before mixing. The volumetric flow rate of each stream is 5 dm3/min, and the entering temperature is 300 K. The streams are mixed immediately before entering. Two reactors are available. One is gray 200 dm3 CSTR that can be heated to 77°C or cooled to 0°C, and the other is a white 800 dm3 PFR operated at 300 K that cannot be heated or cooled but can be painted red or black. Note k = 0.07 dm3/mol.min at 300 K and E = 20 kcal/mol.
Select type of reactor that could be used by showing appropriate calculations.
Calculate time taken to achieve 90% conversion in a 200 dm3 batch reactor with CA0 = CB0 = 1 M after mixing at a temperature of 77°C.
Repeat part (b) if the reactor were cooled to 0°C
Calculate the conversion if the CSTR and PFR were operated at 300 K and connected in series. The entering volumetric flow rate is 10 dm3/h.
Repeat part (d) if CSTR and PFR are connected in parallel with an entering flow rate of 5 mol/min to each of the reactor.

3. Select type of reactor that could be used by showing appropriate
calculations.
CSTR
Design equation:
Rate Law:
Stoichiometry:
Combine:

4. Using Arrhenius eq, find k at T=350K
Select type of reactor that could be used by showing appropriate
calculations.
CSTR
Using Arrhenius eq, find k at T=350K
Solving for X,

5. Select type of reactor that could be used by showing appropriate
calculations.
PFR
Design equation:
Rate Law:
Stoichiometry:
Combine:
Solving for X:
X= 0.85

6. 200dm3 CSTR gives higher conversion than 800dm3 PFR
Select type of reactor that could be used by showing appropriate
calculations.
200dm3 CSTR gives higher conversion than 800dm3 PFR
Thus, CSTR is chosen.

7. (b) Calculate time taken to achieve 90% conversion in a 200 dm3 batch reactor with CA0 = CB0 = 1 M after mixing at a temperature of 77°C.
Batch
Design equation:
Rate Law:
Stoichiometry:
Combine:
Solving for t:

8. (b) Calculate time taken to achieve 90% conversion in a 200 dm3 batch reactor with CA0 = CB0 = 1 M after mixing at a temperature of 77°C.
Solving for t:

9. (c) Repeat part (b) if the reactor were cooled to 0°C
Using the same equation in part (b), except the value of k is used at T= 273K.
From Arrhenius eq,
Thus,

10. (d) Calculate the conversion if the CSTR and PFR were operated at 300 K and connected in series. The entering volumetric flow rate is 10 dm3/h.
v0=10 dm3/h.

11. (d) Calculate the conversion if the CSTR and PFR were operated at 300 K and connected in series. The entering volumetric flow rate is 10 dm3/h.
v0=10 dm3/h.

12. (e) Repeat part (d) if CSTR and PFR are connected in parallel with an entering flow rate of 5 dm3/h to each of the reactor.
5 dm3/h.
10 dm3/h.
5 dm3/h.

13. (e) Repeat part (d) if CSTR and PFR are connected in parallel with an entering flow rate of 5 dm3/h to each of the reactor.
5 dm3/h.
10 dm3/h.
5 dm3/h.