Gas-based fertilizer complexes: what is the principal role of natural gas in such plants with respect to ammonia production?

Introduction / Context:
Ammonia plants require a large supply of hydrogen. In gas-based fertilizer complexes, natural gas is the dominant feedstock because it reformats efficiently into synthesis gas with a high hydrogen yield and relatively low carbon intensity compared with oil/coal routes. While natural gas may also serve as a fuel, its defining role is as a hydrogen source for the ammonia loop.

Given Data / Assumptions:

• Plant type: gas-based (not coal-based/coke-oven gas).
• Core step: steam reforming/ATR of methane-rich gas to H2 + CO/CO2.
• Downstream: shift, CO2 removal, methanation, and ammonia synthesis with N2.

Concept / Approach:
Natural gas (primarily methane) reacts with steam to yield hydrogen. The produced CO is shifted with steam to additional H2 and CO2. After CO2 removal and polishing, the H2 combines with nitrogen in the Haber–Bosch loop. Although natural gas also fires furnaces, the answer focuses on its principal process role in gas-based fertilizer plants.

Step-by-Step Solution:
Identify the hydrogen source in a gas-based plant: natural gas via reforming.Acknowledge ancillary usage as fuel but not the core process identity.Exclude coal gas options as they pertain to coal-based schemes.Choose the option stating natural gas provides hydrogen for ammonia.

Verification / Alternative check:
Standard ammonia technology references describe the natural-gas reforming route as the global workhorse for H2 supply in fertilizer industry.

Why Other Options Are Wrong:
“Only heating medium” understates the central role of gas as chemical feed.Coal gas options describe a different, coal-based flowsheet not applicable here.

Common Pitfalls:
Confusing fuel service with feedstock service; overlooking that natural gas fulfills both roles but is principally valued for its hydrogen yield.

Final Answer:
Natural gas is used as the source of hydrogen for ammonia synthesis