LNG storage tank cold insulation design

LNG storage tank cold insulation design

The purpose of cold insulation design of LNG storage tank is to meet process production requirements, maintain and exert production capacity, reduce cold loss, save energy, prevent condensation on the outer surface of the storage tank, and improve the working environment. The cold storage structure of cryogenic storage tanks must first consider the cold and heat insulation properties of cryogenic liquids. For different storage conditions, different structures and insulation materials are used accordingly.

Expanded perlite is selected for the inner and outer wall interlayer as the cold insulation material, and the side wall is cold insulation because of the expanded perlite. After the temperature of the storage tank filled with cryogenic liquid is cooled, the shrinkage of the inner tank will make the upper part of the side wall and the edge area of the storage tank insufficient to fill the expanded perlite, and the cryogenic storage tank cannot be filled with expanded perlite again after pre-cooling. In order to prevent the ingress of moist air, the method of adding a layer of elastic thermal insulation glass fiber mat on the outer wall of the inner tank of the storage tank can avoid the secondary filling of perlite and reduce the pressure of perlite on the inner tank wall.

The cold insulation material and cold insulation structure design at the bottom of the LNG storage tank must not only ensure that the cold loss of the storage tank is reduced to a small amount, but also the compressive strength of the cold insulation material must be able to withstand the total weight of the inner tank and the cryogenic liquid and the gas pressure. In the design and construction of the 20000m³cryogenic storage tank, according to the different pressures on the bottom of the storage tank and the principle of minimizing the cold loss rate, the bottom heat insulation structure is divided into two parts, the pressure ring and the center ring, and different The cold insulation material. The pressure ring is the main component that bears the weight of the inner tank, and its strength requirements are relatively high. Therefore, the composite structure of concrete and glass brick is used as the cold insulation material of the pressure ring. For the central part of the bottom, glass bricks alone can meet the design requirements for strength and cold insulation.