Assessment of rollover effects at large LNG atmospheric and pressure storage tanks.

Abstract

Roll-over effect is subject of concerns at LNG storage. It is a result of non-homogenous composition of the stored amount of LNG. Mixing of bulks of liquids of different concentration and saturation to boiling points at different pressure results in release of heat in a vapour phase, which can cause venting of gas or increase of pressure, as it was experienced at several locations. This was subject of studies, especially for LNG storage in large flat bottom tanks at atmospheric pressure. Models of origination of roll-over effect were published. This paper presents a method of forecast of the quantity of vented gas or pressure increase as function of size, LNG composition and pressure of the system.