Tanker Inert Gas & Nitrogen Purging Time and Cost Tool
Estimate gas volume, source-limited purging time, tank-batch
sequencing, inert-gas or nitrogen production cost, electrical
energy, fuel use, labor and vessel-time exposure. Advanced mode
models multiple tank groups and different gas sources without
prescribing gas-quality targets or operating procedures.
Currency selector changes display only. No exchange-rate conversion is performed.
Gas Volume
Tank volume × approved gas-volume exchanges × contingency
Elapsed Time
Per-tank flow, tanks in parallel, source capacity and setup time
Operating Cost
Gas production, electricity, fuel, labor and vessel-time exposure
Tank Purging Work Package
Enter the gas-volume exchanges required by the vessel's approved
plan, cargo procedure or engineering assessment. This tool does
not determine the required number of exchanges.
tanks
m³/tank
exchanges
User-entered planning value from an approved procedure or engineering basis.
%
tanks
Nm³/h
Nm³/h
Enter 0 to model no source-capacity constraint.
hours
hours
hours
Gas Production & Energy Cost
Only the selected gas source is used in Simple mode. All factors
are editable and should be replaced with vessel or supplier data.
kg/1,000 Nm³
kWh/1,000 Nm³
kWh/1,000 Nm³
$
/1,000 Nm³
$
/MT
$
/kWh
Labor & Vessel-Time Economics
people
$
/person-hour
$
/hour
$
Tank Groups
Tank groups are modeled sequentially. Tanks within each group can
be processed in parallel. Required gas-volume exchanges are user
inputs from approved vessel procedures or engineering criteria.
Tank Group
Gas
Tanks
Volume m³/Tank
Exchanges
Parallel
Flow/Tank Nm³/h
Setup h/Batch
Gas Source Capacity
Nm³/h
Nm³/h
Nm³/h
%
hours
hours
Production Cost Factors
kg/1,000 Nm³
kWh/1,000 Nm³
kWh/1,000 Nm³
$
/1,000 Nm³
$
/MT
$
/kWh
Labor & Vessel-Time Economics
people
$
/person-hour
$
/hour
$
Purging Time & Cost Results
Single tank-group analysis
Enter tank data
Enter tank vapor-space volume, required gas-volume exchanges and
flow assumptions to estimate time, gas demand and operating cost.
Total Purging Operation Time
N/A
Active gas-flow time plus batch setup and fixed preparation time
Total Modeled Cost
N/A
Gas production + labor + vessel-time exposure + fixed cost
Required Gas Volume
N/A
Active Flow Time
N/A
Batch / Setup Time
N/A
Source-Limited Groups
N/A
IG Volume
N/A
Generated Nitrogen
N/A
Purchased Nitrogen
N/A
Electrical Energy
N/A
Fuel Use
N/A
Gas Production Cost
N/A
Cost per Tank
N/A
Cost per 1,000 Nm³
N/A
Target Time Gap
N/A
Vessel-Time Exposure
N/A
Tank Group Results
Advanced mode
Group
Gas
Tanks
Gas Volume
Batches
Active Time
Total Time
Source Cap
Status
Cost Breakdown
Gas Source Summary
Operation Summary
Elapsed-Time Sensitivity
Required exchanges vs source capacity
Exchanges \ Capacity
-20%
Base
+20%
Model approach:
required gas volume equals tank vapor-space volume × user-entered
required gas-volume exchanges × gas-volume contingency. Tanks are
processed in batches according to the entered parallel-tank limit.
Effective batch flow is the lower of requested aggregate flow and
entered source capacity. Gas-source cost is calculated from
user-entered inert-gas fuel/electricity factors, nitrogen-generation
electricity or purchased nitrogen price. This tool intentionally
does not calculate safe oxygen, hydrocarbon or toxic-gas
concentrations, required exchange counts or purging endpoints.
Planning estimate only.
Tanker inerting, purging and gas replacement are safety-critical
operations involving flammable, toxic, oxygen-deficient or otherwise
hazardous atmospheres. Actual requirements depend on cargo history,
cargo properties, tank condition, vessel design, inert-gas or nitrogen
system capability, piping arrangements, pressure limits, gas quality,
instrumentation, approved operating procedures, terminal requirements,
flag and class requirements and applicable regulations. This tool does
not determine the required number of gas-volume exchanges, oxygen
limits, hydrocarbon limits, gas-freeing criteria, purging sequence,
tank-entry conditions, valve configuration, pressure settings or safe
operating procedure. Use vessel-specific approved procedures,
calibrated instrumentation and competent professional oversight for
all operations.
