MChem Master of Chemistry Master of Chemistry: Industrial Chemistry 2 — Questions and Answers
Question 1: Which catalyst is used in the industrial Haber-Bosch process for ammonia synthesis?
- Platinum on alumina
- Iron with potassium and aluminum oxide promoters (Correct answer)
- Vanadium pentoxide
- Nickel on silica
Correct answer: Iron with potassium and aluminum oxide promoters
The Haber-Bosch process uses an iron catalyst promoted with K2O (electronic promoter) and Al2O3 (structural promoter).
Question 2: In the Contact Process for sulfuric acid production, what is the role of vanadium pentoxide (V2O5)?
- It absorbs SO3 into oleum
- It catalyzes the oxidation of SO2 to SO3 (Correct answer)
- It removes moisture from the gas stream
- It converts H2S to SO2
Correct answer: It catalyzes the oxidation of SO2 to SO3
V2O5 catalyzes the key step SO2 + ½O2 → SO3 by cycling between V5+ and V4+ oxidation states.
Question 3: What is the primary purpose of a heat exchanger network in an industrial chemical plant?
- To increase reaction conversion
- To recover and reuse thermal energy between process streams (Correct answer)
- To maintain catalyst activity
- To control reactor pressure
Correct answer: To recover and reuse thermal energy between process streams
Heat exchanger networks use hot process streams to preheat cold ones, minimizing external utility consumption through energy integration.
Question 4: Which phenomenon describes the minimum temperature difference between hot and cold streams in a heat exchanger network?
- Flash point
- Pinch temperature (Correct answer)
- Dew point depression
- Leidenfrost point
Correct answer: Pinch temperature
The pinch temperature (or pinch point) is the minimum driving force ΔTmin that constrains the thermodynamic feasibility of heat integration.
Question 5: In distillation column design, what does the McCabe-Thiele method graphically determine?
- Reactor residence time
- Number of theoretical stages required for a separation (Correct answer)
- Heat duty of the reboiler
- Column diameter from vapor velocity
Correct answer: Number of theoretical stages required for a separation
The McCabe-Thiele method uses operating lines and an equilibrium curve on a y-x diagram to step off the number of theoretical stages.
Question 6: What does the term 'space time yield' (STY) measure in industrial catalytic reactors?
- Selectivity of desired product over byproducts
- Mass of product formed per unit reactor volume per unit time (Correct answer)
- Catalyst lifetime before regeneration
- Conversion at steady-state conditions
Correct answer: Mass of product formed per unit reactor volume per unit time
Space time yield (kg product / m³ reactor / h) is a key performance metric comparing the productivity of different reactor designs.
Question 7: Which industrial process converts naphtha into high-octane aromatics and hydrogen using a platinum-rhenium catalyst?
- Fluid catalytic cracking
- Catalytic reforming (platforming) (Correct answer)
- Hydrocracking
- Steam cracking
Correct answer: Catalytic reforming (platforming)
Catalytic reforming (e.g., UOP Platforming) dehydrogenates and cyclizes naphtha over Pt-Re/Al2O3 to produce aromatics and H2.
MChem Master of Chemistry Master of Chemistry: Industrial Chemistry 2
Which catalyst is used in the industrial Haber-Bosch process for ammonia synthesis?