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Vapor Return - Rate vs Load Rate

Vapor-return gas volume during loading - matches the liquid load rate corrected for tank ullage temperature, used to size VECS manifold.

Vapor returnMARPOL VITanker
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Formula, assumptions, and limits

V˙vap=V˙liqTtankTref\dot V_{vap} = \dot V_{liq} \cdot \frac{T_{tank}}{T_{ref}}
SymbolMeaningUnit
V˙liq\dot V_{liq}Cargo loading ratem³/h
TtankT_{tank}Tank vapor temperatureK
TrefT_{ref}Terminal reference TK

Source: MARPOL Annex VI Reg. 15

In short

Vapor-return gas volume during loading - matches the liquid load rate corrected for tank ullage temperature, used to size VECS manifold.

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