Nitrogen volume required for a displacement (layered, density-driven) purge - used to inert LNG cargo tanks before gassing-up, ~1.05× tank volume when well-controlled.
Formula
$$ V_{purge} = \frac{V_{tank}}{\eta_{disp}} $$
Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| $V_{tank}$ | Tank gross volume | m³ | capacity plan |
| $\eta_{disp}$ | Displacement efficiency | - | SIGTTO guidance |
Sources
- SIGTTO - Liquefied Gas Handling Principles 4th ed..