Ammonia plant front-end catalysis: which catalyst is commonly used for steam reforming of naphtha to generate hydrogen-rich syngas?

Introduction / Context:
Steam reforming converts hydrocarbons into hydrogen and carbon oxides and is the backbone of most hydrogen generation systems feeding ammonia synthesis. Catalyst choice must balance activity, cost, and resistance to coking and sulfur poisoning. This item focuses on the standard catalyst for reforming light hydrocarbons like naphtha.

Given Data / Assumptions:

• Naphtha feed pretreated to remove sulfur (e.g., via ZnO guard bed).
• High-temperature tubular primary reformer with fired furnace.
• Goal is robust H2 production at reasonable cost.

Concept / Approach:
Nickel on alumina or other ceramic supports is the industrial workhorse for steam reforming of hydrocarbons because it provides high activity for C–H bond activation at a far lower cost than noble metals. While Pt or Rh have high activity, they are typically reserved for specific oxidation or partial oxidation duties due to cost. Silica gel is not a reforming catalyst; ZnO is used upstream to remove H2S, not as the reforming catalyst itself.

Step-by-Step Solution:

Verification / Alternative check:
Process licensors and textbooks consistently specify Ni-based catalysts for primary reformers in ammonia plants.

Why Other Options Are Wrong:

• Pt/Rh: too costly for primary reforming duty in large plants.
• Silica gel: not a catalyst for reforming.
• ZnO: guard for sulfur removal, not the reformer catalyst.

Common Pitfalls:
Confusing guard bed materials with the actual reforming catalyst, or assuming noble metals are used simply because they are “better.” Cost and availability rule in large-scale ammonia plants.

Final Answer:
Nickel (Ni) on porous support.