“Solvent naphtha” used in paints and perfumery is produced by splitting virgin naphtha into narrow boiling-range cuts. Identify the refinery operation primarily used to make such solvent-grade streams from virgin naphtha.

Introduction / Context:
Solvent naphtha is a refined fraction designed for solvent applications, including coatings and perfumery. Key to its performance are volatility range, odor, and purity. Achieving a narrow boiling range allows formulators to control evaporation rate and solvency characteristics in end-use products.

Given Data / Assumptions:

• Feed: virgin (straight-run) naphtha from the crude distillation unit.
• Target: narrow cuts with controlled boiling ranges.
• Quality: low sulfur/odorous impurities may be addressed separately.

Concept / Approach:
The primary operation to split a wide-boiling-range naphtha into solvent-grade streams is distillation (fractionation or redistillation). By setting appropriate cut points, specific solvents (e.g., light, medium, or heavy solvent naphtha) are obtained. While hydrotreating/desulphurisation can reduce odor and reactive impurities, the basic creation of “small boiling range cuts” is accomplished through distillation itself. Steam reforming is unrelated; it converts light hydrocarbons to synthesis gas, not solvents.

Step-by-Step Solution:

Verification / Alternative check:
Solvent-grade product specifications routinely reference distillation ranges per standardized methods; production involves fractionation and, if needed, subsequent treating for odor and color.

Why Other Options Are Wrong:

Common Pitfalls:
Assuming “solvent naphtha” is a single fixed composition; it is a family of cuts defined by distillation behavior.

Final Answer:
Distillation