In catalytic reforming of straight-run or hydrotreated naphtha, what is a representative gasoline (reformate) liquid yield expressed as percent by weight, excluding by-product hydrogen and light gases?

Introduction:
Catalytic reforming upgrades low-octane naphtha into high-octane reformate and produces hydrogen. Knowing typical reformate yield helps in refinery LP planning, hydrogen balance, and octane pool forecasting.

Given Data / Assumptions:

• Feed: naphtha in the gasoline boiling range.
• Process: semi-regenerative or continuous catalyst regeneration reforming.
• We are asked for a representative liquid reformate yield by weight, not counting H2 and C1–C4 gases.

Concept / Approach:
Reforming involves dehydrogenation, isomerisation, cyclization, and dehydrocyclization. These steps generate hydrogen and some light ends (C1–C4), so the liquid reformate yield is less than 100% of feed. A typical planning value lies around the mid-80s wt%, subject to severity and feed composition. Hence, 85 wt% is a sensible representative figure.

Step-by-Step Solution:
1) Recognize that reforming consumes part of the feed as light gases and H2.2) Recall planning heuristics: reformate yields ~80–90 wt% depending on severity and feed paraffinicity.3) Choose 85 as a representative middle value.

Verification / Alternative check:
Licensor and textbook examples often show yields near 83–88 wt% for standard severities; severe reforming for high octane typically lowers yield slightly.

Why Other Options Are Wrong:
65 or 50: Too low for typical operation; would imply excessive cracking.98: Unrealistically high given H2 and light gas formation.72: Low relative to mainstream planning figures.

Common Pitfalls:
Assuming reforming is purely rearrangement with no yield loss; dehydrogenation and side cracking inevitably produce off-gas.

Final Answer:
85