Jiskoot IsoFraction LNG sampling system

Applications

• LNG custody transfer measurement.
• LNG carrier loading and unloading operations.
• LNG import and export terminals.
• Online gas chromatograph (GC) feed systems.
• LNG quality verification and batch certification

Benefits

• Representative LNG sampling for custody transfer applications.
• Accuracy better than ±0.15%.
• Unaffected by variations in line pressure and flow rate.
• Fully automated operation with no routine operator intervention.
• Reduced risk of human error.
• Compact, low-maintenance system design.
• ISO 8943 compliant.

Features

• Integrated LNG vaporisation, stabilisation, and control system.
• Continuous gas conditioning to maintain the sample above its dew point.
• Constant Pressure Cylinder (CPC) sample collection technology.
• Multiple independent sampling streams for sample verification.
• Integrated validation points for representative GC feed verification.
• Compatible with online gas chromatographs.
• Spot sampling capability at key batch intervals.

How it improves performance

The Jiskoot IsoFraction™ LNG sampling system was developed to overcome the challenges associated with conventional LNG sampling and gas chromatograph (GC) feed systems. LNG is extracted from the process stream and routed through an integrated vaporisation, stabilisation, and control system that carefully manages the transition from liquid to gas phase, minimising lag and ensuring sample integrity throughout the phase-change process. Once vaporised, the gas stream is maintained above the dew point of its constituent components before entering the sampling system.

To support representative GC analysis, the system incorporates dedicated take-off points that enable validation and verification of GC feed representativity. The high volume of conditioned gas flowing through the system provides a significant advantage over conventional sampling methods, helping to ensure that both the collected sample and the gas supplied to the GC remain representative of the process stream.

The system typically employs three gas samplers installed on a common process loop, enabling three independent but comparable composite samples to be collected throughout the transfer operation. Gas samples are extracted into Constant Pressure Cylinder (CPC) receivers, where the use of fixed-pressure, variable-volume piston technology minimises atmospheric contamination and cross-batch contamination while allowing a large number of small sample grabs to be accumulated. This approach maximises overall sample representativity for custody transfer and quality measurement applications.

In addition to composite sampling, the IsoFraction system can extract fixed-volume spot samples into conventional 500 ml sample receivers at key intervals throughout a batch, typically at 25%, 50%, 75%, and 100% completion. The system also incorporates pre-purging functionality to help verify sampling conditions and maintain representative spot sampling performance. Combined with its fully automated operation, this reduces operator intervention and improves sampling consistency throughout the transfer process.