Definition of “gas-based” fertilizer plant: A fertilizer plant is classified as gas-based when it uses which gas as the primary hydrogen source for ammonia manufacture?
-
ACoke oven gas
-
BProducer gas from solid fuels
-
CNatural gas (methane-rich)
-
DCoal gas from gasification as solids feed
-
ERefinery fuel gas only
Answer
Correct Answer: Natural gas (methane-rich)
Explanation
Introduction / Context:Ammonia synthesis requires hydrogen, traditionally obtained by reforming hydrocarbons. Industry shorthand categorizes plants by the primary feedstock to the hydrogen unit. A “gas-based” plant refers specifically to facilities using natural gas—largely methane—as the principal hydrogen source via steam reforming or autothermal reforming.
Given Data / Assumptions:
- Hydrogen is produced upstream of the Haber–Bosch loop.
- Feedstock options include natural gas, naphtha, coal/coke oven gas, and others.
- Classification is based on main feedstock, not minor supplements.
Concept / Approach:“Gas-based” denotes natural gas-based hydrogen production, which is common due to methane's high hydrogen-to-carbon ratio, established steam methane reforming technology, and widespread pipeline infrastructure. While coke oven or producer gases can contain hydrogen and be processed, plants using these are typically called “by-product gas-based” or classified under separate schemes, not the standard “gas-based” label in fertilizer sector reporting.
Step-by-Step Solution:
Identify definition: gas-based ≈ natural gas feed to reformers.Associate with SMR/ATR → hydrogen-rich syngas for NH3.Select “Natural gas (methane-rich)” as correct.Verification / Alternative check:National fertilizer statistics typically segregate capacity as gas-based (natural gas), naphtha-based, fuel oil/LSHS-based, or coal-based, confirming the accepted usage.
Why Other Options Are Wrong:
- Coke oven gas and producer gas can be hydrogen sources but are not the standard meaning of “gas-based” in this context.
- Coal gasification routes are categorized as “coal-based.”
- Refinery fuel gas varies and is not the canonical definition.
Common Pitfalls:Assuming any gaseous feed qualifies; sector nomenclature specifically points to natural gas-based hydrogen generation.
Final Answer:Natural gas (methane-rich).