Regarding the insulation design of the upper part of the tank, since the insulation material is covered on the ceiling of the inner tank, it does not need to bear the pressure from the equipment and evaporated gases (only the weight of the insulation material itself), the insulation material needs to have low thermal conductivity and low density characteristics. The upper part of the inner tank of the low-temperature natural gas tank is made of glass wool, with an insulation thickness of 500mm, installed in five layers, and the outer side of the upper glass wool is coated with aluminum foil to prevent expanded perlite and other impurities from entering the inner tank through gaps.

Because the sandwich of the inner and outer walls chooses expanded perlite as the insulation material, the side wall insulation also uses expanded perlite. After the tank filled with low-temperature liquid is cooled, when the inner tank shrinks, the expanded perlite filled in the upper and peripheral areas of the tank side wall is insufficient. The low-temperature tank cannot be refilled with expanded perlite after pre-cooling. To prevent the intrusion of humid air, a method of adding elastic insulation glass wool mat to the outer wall of the tank is used, which can avoid the secondary filling of perlite and reduce the pressure on the inner tank wall of the perlite.

The insulation material and structure at the bottom of the liquefied natural gas storage tank not only reduce the cold loss of the tank but also ensure that the compressive strength of the insulation material can withstand the total weight of the inner tank and the low-temperature liquid as well as the vapor pressure. In the design and construction of the 20000m low-temperature oil storage tank, the pressure differences at various parts of the tank bottom and the principle of significantly reducing the freezing loss rate are considered.

The bottom insulation structure is divided into two parts: the pressure-bearing ring and the central ring, using different insulation materials. The pressure-bearing wheel is the main component bearing the weight of the inner tank, so its strength requirements are relatively high. Therefore, the insulation material for the pressure-bearing wheel uses a composite structure of concrete and glass bricks, while the central part at the bottom can meet the strength and insulation design requirements with glass bricks alone.