Fuel specification: What is the approximate maximum sulfur content (mass %) specified for low-sulfur heavy stock (LSHS) furnace oil?

Introduction / Context:
Industrial and utility fuels are classified by sulfur content due to air emission limits and corrosion concerns. LSHS (low-sulfur heavy stock) is a residual-type furnace oil with restricted sulfur content to reduce SOx emissions and fouling.

Given Data / Assumptions:

• LSHS is a lower-sulfur residual fuel compared with conventional furnace oil.
• Regulatory and specification frameworks vary by region; the question seeks a commonly cited nominal limit.

Concept / Approach:
Typical teaching references place LSHS sulfur near or below 1 % by mass, differentiating it from higher-sulfur furnace oils (2.5–3.5 % or more). The value communicates the “low sulfur” character of the grade.

Step-by-Step Solution:
Identify LSHS intent → low sulfur residual fuel.Common nominal maximum → about 1 % S.Select “1 %” from the options.

Verification / Alternative check:
Procurement specs and legacy refinery texts list LSHS ≈ 1 % S max, subject to local standards.

Why Other Options Are Wrong:

• 0.1 %: characteristic of ultra-low sulfur distillates, not residual LSHS.
• 2.5–3.5 %: typical of higher-sulfur furnace oils.
• 5 %: far above “low-sulfur” classification.

Common Pitfalls:
Assuming global uniformity; always check current local fuel standards.

Final Answer:
1 %