Hydrogen-to-carbon ratio by weight: Among these refinery streams, which typically has the maximum H/C ratio by weight?

Introduction:
The hydrogen-to-carbon ratio (by weight) increases as hydrocarbons become lighter and more paraffinic. This metric correlates with cleaner combustion and higher mass-based heating value.

Given Data / Assumptions:

• Compare representative refinery streams from light to heavy.
• Assume typical crude slate and standard boiling ranges.

Concept / Approach:
Lighter fractions (e.g., naphtha) have higher hydrogen content relative to carbon than heavier, more aromatic/asphaltenic fractions (diesel, fuel oil, residues). Therefore, naphtha shows the highest H/C by weight among the listed options.

Step-by-Step Solution:

Verification / Alternative check:
Assay data and hydrogen balance calculations reflect rising H/C with lighter cuts.

Why Other Options Are Wrong:

• Gasoline: Slightly heavier/more aromatic than light naphtha on average.
• Diesel / Fuel oil / Residue: Progressively heavier and more carbon-rich.

Common Pitfalls:
Confusing volumetric energy density trends with H/C ratio trends.

Final Answer:
Naphtha