Pre-vapourisation and enrichment occur when the LNG sample is not completely vapourised in a single step. Partial vapourisation leads to the most volatile components vapourising first, leaving an enriched sample in the liquid phase. Both phases are not representative of the true sample composition.

Only by vapourising the sample in a single step will the true composition be achieved which then can be analysed. Often the LNG sampling system is common to both the online GC and the incremental samplers which are analysed subsequently in the laboratory, this means any sampling problems cannot be identified through the observed differences between online and laboratory results. This highlights the need for an LNG sampling system inspection.

For more information about our LNG sampling system inspections, click here.

If you’d like to learn more about our LNG Sampling training course, click here.