LNG CARGO • NATURAL BOG • FUEL USE • RELIQUEFACTION • CARGO LOSS • COMMERCIAL EXPOSURE

LNG Carrier Boil-Off Gas & Cargo Loss Tool

Convert entered boil-off rates and voyage conditions into a transparent LNG mass balance. Separate gross natural BOG from gas used as fuel, BOG returned by reliquefaction, controlled destruction/handling and any unresolved excess, then quantify delivered cargo and commercial exposure without pretending that boil-off automatically equals cargo loss.

Figures represent
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Need segment-by-segment BOG handling, GCU capacity, reliquefaction power or annual commercial exposure?Click Advanced above. Simple gives a fast laden-voyage mass balance from exactly 10 primary inputs.
Mass balanceGross BOG → fuel → reliq → excess
CargoDelivered mass & non-delivery
CommercialCargo value exposure

Cargo & Voyage

Enter the loaded LNG condition and the natural daily boil-off rate used for this planning case.

m³ liquid LNG loaded.
% of entered liquid cargo volume basis.
kg/m³. Use cargo-specific density when known.
days before cargo discharge.
% of current liquid inventory per day.
MT/day maximum natural BOG consumed as fuel.
MT/day nameplate processing capacity.
% effective availability during the voyage.
$/MT commercial cargo value basis.
For annualized non-delivery exposure.
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Advanced separates each voyage phase and each BOG disposition path.Use actual ship/reliquefaction/GCU operating limits where available. The model is a cargo mass-balance and commercial screen, not a cargo-containment pressure simulation.

Cargo & Commercial Basis

These assumptions define starting liquid cargo, retained heel and the economic value of cargo, fuel use and BOG handling.

m³ liquid LNG.
%.
kg/m³.
MT retained, not treated as cargo loss.
$/MT.
Annualization basis.
$/MT BOG beneficially consumed as fuel.
kWh per MT BOG processed.
$/MWh for reliquefaction power.
$/MT processed.
$/MT controlled BOG destruction/handling.
$ per laden voyage.

Voyage BOG Program

BOG is generated from the current liquid inventory. Natural BOG is allocated to fuel first, then reliquefaction, then controlled GCU handling. Any amount beyond the entered GCU capacity is flagged as unresolved excess requiring additional operating action.

UsePhaseDaysBOR %/dFuel BOG MT/dReliq MT/dReliq avail %GCU cap MT/d

Stress Cases

Stress gross BOR, voyage duration and BOG-handling performance without changing the base inputs.

UseCaseBOR ×Days ×Fuel capacity ×Reliq avail ×
BOG cargo mass balance

Cargo-loss position

Live results appear here as assumptions change.

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Net cargo not delivered.

Gross natural BOG-Generated during entered voyage
BOG used as fuel-Beneficial onboard use
Reliquefied-Returned to liquid cargo
Unrecovered cargo-GCU + unresolved excess
Cargo not delivered-Fuel use + unrecovered
Final liquid cargo-Before heel deduction
Deliverable cargo-After retained heel
Net BOG economic exposure-After entered fuel credit

BOG Mass Flow

Gross natural boil-off separated into the actual handling paths entered in the model.

Beneficial recovery-
Non-delivery rate-
Unresolved excess-
Annual non-delivery-

Cargo Delivery Bridge

Tracks the initial liquid cargo through voyage BOG disposition to final deliverable LNG.

Voyage BOG Handling Profile

Phase-by-phase BOG generation and handling. Any red residual requires additional operating action beyond the entered capacities.

Commercial Exposure

Cargo value not delivered plus BOG-handling cost, offset by the entered value of BOG beneficially used as fuel.

Cargo value not delivered-
Fuel-use credit-
Reliq energy-
Annual net exposure-

Liquid Cargo Through Voyage

Liquid inventory declines only when BOG is consumed as fuel or otherwise not returned by reliquefaction.

Liquid cargo inventory

BOR × Voyage Duration Sensitivity

Net cargo not delivered under simultaneous changes to boil-off rate and voyage duration. Advanced uses the entered voyage program as the base case.

Advanced Stress Cases

Independent cases using the entered multipliers.

Model Boundaries

This calculator is a planning mass-balance and commercial screen. The entered BOR is an operating assumption, not a thermodynamic prediction. Actual LNG boil-off depends on containment design, tank pressure, filling level, weather, sea state, cargo composition and operating practice. The tool does not establish allowable tank pressure, MARVS margin, venting authorization, gas-combustion safety, reliquefaction operability or cargo quality. Use approved cargo-containment, gas-management and operating procedures for vessel decisions.
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