LNG BOG • BOR • Fuel Gas • Reliquefaction • GCU • Emergency Vent Scenario • Cargo Depletion • Tank Pressure • Energy & Reliq Power
LNG Cargo Boil-Off & Reliquefaction Tool BOG Rate, Cargo Loss, Fuel Use & Tank Pressure
Model what happens to LNG boil-off during a laden voyage instead of treating BOR as simple cargo loss. The tool separates gross BOG generation from fuel consumption, reliquefaction, GCU destruction, emergency venting and vapor accumulation, then tracks remaining liquid cargo, retained onboard mass, energy recovered as fuel, reliquefaction power and an empirical tank-pressure trend against action and MARVS limits.
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Need voyage legs, GCU, reliquefaction power, cargo value or emergency-pressure scenarios? Click Advanced above.Simple routes BOG to fuel first, then reliquefaction. Any remaining vapor accumulates onboard and drives the empirical pressure trend.BOG balanceGenerated → fuel → reliq → vapor
CargoLiquid & retained mass
PressureAction / MARVS timeline
Cargo & Voyage
m³.
kg/m³.
% of current liquid mass per day.
days.
maximum t/day.
t/day returned to liquid.
Tank Pressure Screen
bar(g).
bar(g), ship-specific.
bar(g), user-entered approved value.
bar/day observed or approved planning coefficient if all generated BOG accumulated.
Cargo, Energy & Commercial Basis
kg/m³.
% current liquid mass/day before leg multiplier.
MJ/kg.
% screening conversion of BOG fuel energy to shaft energy.
currency/tonne.
BOG Handling Plant
t/day.
t/day.
kWh per tonne BOG processed.
t/day.
t/day. Normal pressure control by venting is not modeled as acceptable.
Pressure-Accumulation Model
bar(g).
bar(g), user-entered vessel limit.
bar(g).
bar/day if generated BOG accumulated under comparable conditions.
bar(g), prevents the empirical model from implying unrealistic vacuum/low pressure.
Voyage Leg Register
Each leg sets voyage duration, BOR multiplier, gas-fuel demand, reliquefaction/GCU availability and pressure-rise multiplier. The simulation runs in six-hour increments, carrying liquid mass and vapor inventory from one leg into the next.
| Use | Leg type | Days | BOR × | Fuel demand t/d | Reliq avail % | GCU avail % | Pressure-rise × |
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BOG Management Checks
IGC / engineering limitation: the IGC Code requires cargo pressure and temperature to remain within containment-system design limits using approved methods such as reliquefaction, thermal oxidation, pressure accumulation or liquid cooling. Normal venting is not acceptable as a pressure-control method except for emergency/permitted cases. The pressure trace below is therefore a ship-specific empirical screening model based on the entered no-handling pressure-rise coefficient. It is not a vapor-equilibrium, tank-structural or PRV sizing calculation.