Crude description by salt content: A crude oil is termed “salty” when its total dissolved salts (as NaCl) exceed approximately what mass per thousand barrels of crude?

Introduction / Context:
Salt (mostly NaCl) enters crude with formation water and brine emulsions. Excess salt causes corrosion, fouling, and catalyst poisoning, so refineries classify and treat salty crudes more aggressively in desalter units. Recognising the conventional threshold helps in feed acceptance and desalter design.

Given Data / Assumptions:

• Salt expressed as mass of NaCl per thousand barrels of crude.
• Rule-of-thumb threshold for “salty crude” used in exam-style questions.
• Units intentionally posed in kilograms per thousand barrels for comparison.

Concept / Approach:
Industry shorthand often flags crudes above roughly 25 kg NaCl per thousand barrels (≈ 55 lb per thousand barrels) as “salty,” indicating significant brine carryover and emulsion stability issues. While individual refineries may set different limits, this benchmark captures the conventional teaching number for classification.

Step-by-Step Solution:

Verification / Alternative check:
Desalter manuals classify feed severity using salt ranges; values near or above 25 kg/MBbl require robust wash and electrostatic treatment.

Why Other Options Are Wrong:

Common Pitfalls:
Mixing “ptb” (pounds per thousand barrels) with kilograms; keep units consistent when comparing limits.

Final Answer:
25