Faculty of Engineering & the Built Environment
Department of Chemical Engineering
Bellville Campus
Assessment 3 – Sick Test
Date: 08-05-2025
Duration: 1.5 hrs
Total Marks: 60
Lecturer Name: Mrs Ashleen Marshall
Subject Name: Chemical Engineering Technology Subject Code: CET261S
Year: 2025 Semester: 1
GA development None
Answer Sheet
Requirements Total Pages 3
The use of a calculator is allowed
v/d Waal’s constants Appendix 1 –
Standard Conditions Formation Data
Appendices
Formation Data Appendix 2 –
Combustion Data Combustion Data
Question 1
Methanol is synthesized from carbon monoxide and hydrogen in a catalytic reactor. The
fresh feed to the process contains 32.0 mole% CO, 64.0% H 2, and 4.0% N2. This stream
is mixed with a recycle stream in a ratio 5 mol recycle/1 mol fresh feed to produce the
feed to the reactor, which contains 13.0 mole% N 2. A low single-pass conversion is
attained in the reactor. The reactor effluent goes to a condenser from which two streams
emerge: a liquid product stream containing essentially all the methanol formed in the
reactor, and a gas stream containing all the CO, H2, and N2 leaving the reactor. The gas
stream is split into two fractions: one is removed from the process as a purge stream, and
the other is recycle stream that combines with the fresh feed to the reactor.
1.1 Draw a flowchart representing the process above (6)
1.2 For a basis of 500 mol fresh feed/h, calculate:
The production rate of methanol as well as the molar flow rate and
composition of the purge gas (19)
1.3 If the purge stream leaves at 500 deg cel, and 101.3kPa, determine
the volume of the purge stream.
(3)
[28]
Question 2
2.1 Methane is burned in air. No carbon monoxide is present in the combustion
products. If 100 gmole/hr of methane enters the reactor, calculate the molar
compositions of the product gases given the following scenarios:
20% excess air is supplied and there is 90% conversion of methane (5)
2.2 If the reactants enter at ambient temperature (250C) and atmospheric pressure,
but the products leave at 4270C and 1atm, what is the ratio of the volume of the
product produced per volume of feed produced for question (2.1) above? (7)
2.3 What is the amount of energy generated/needed for the reaction to take place in
question (2.1.3) above using the reference temperature of 250C? (10)
Question 3
You are asked to design a steel tank in which ammonia will be stored at 290 K. The tank is
15 m3 in volume and you want to store 200 kg of ammonia in it. What pressure will the CO 2
exert? Use van der Waals equation to solve. (10)
Standard Conditions
