LNG (as fuel) ageing

What is meant by “LNG ageing” and why is it important?
Appreciate if somebody can explain in simple terms.


LNG has components with different boiling points.
Ageing of LNG is the gradual change in its molecular composition caused
by the differential evaporation of the LNG components.
The components in the LNG with lower boiling points (e.g. Methane) evaporate preferentially and hence produce boil off gas (BOG). This reduces the proportion of the most volatile components and increases relatively the less volatile molecules (C2+) in the LNG, thus changing the overall molecular composition of the LNG.
It is important to understand the impact of LNG ageing throughout the supply chain (storage, transportation etc.) because it can affect the LNG specification either as a cargo or as a fuel. Several software prediction tools that can simulate the rate of LNG ageing exist in the market.

For instance, here is a table with the boiling points of the LNG components