Study on safety and reliability of low-temperature tanks with perlite loose insulation during seismic events

A low-temperature tank is a type of tanks, that is used to store gas products in a liquid form at constantly low temperature under relatively low pressure. There are some features in the structure of this type of tanks. The main feature is the presence of thermal insulation. One of the most frequently used variants of low-temperature tanks is the type that consists of two cylindrical vessels with loose perlite insulation in an interwall space. Usually, it is concluded that the inner vessel and outer vessel act independently of each other during seismic events, but the rightness of this assumption is hardly ever investigated. This lack of study may cause serious safety issues, provoking underestimation of seismic loads on the inner and outer vessel as well as neglecting other complex effects such as influence on the form and frequencies of excited modes of the coupled flexible tank wall and fluid motion. In this paper principal effects of loose perlite insulation and its influence on seismic behaviour of two-vessel storages are discussed.