High MW Volatile Component in the Mixture

An important example is LNG with a significant amount ( 1.0 %) of nitrogen. 

During storage of LNG with, say, a composition containing 3 % nitrogen, preferential evaporation of the more volatile nitrogen with MW=28, liquid density 808 kg/m from LNG with MW 16, liquid density 430 kg/m will result in a liquid density reduction towards 420 kg/m of 2.5 %, which is more than enough for auto-stratification. 

It should be noted that the enhanced composition of the vapour with the lower boiling point constituent, due to the surface evaporation effect discussed in Sect. 5.6.2, will further enhance the density reduction in the top layer required for autostratification to take place. 

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