Cryogenic storage tank

Cryogenic storage tank

The cryogenic storage tank is a vertical or horizontal double-layer vacuum insulated storage tank for storing liquid oxygen, nitrogen, argon, carbon dioxide and the like. The material used for the inner tank is austenitic stainless steel; the outer container material is selected according to the national regulations, according to the national regulations, Q235-B, Q245R or 345R, the inner and outer container interlayer is filled with insulating material pearl sand or aluminum foil, heat insulation cotton and vacuum.

There is no uniform standard for the design definition of cryogenic storage tanks themselves. Compared with the UK, the technical standards in this respect are relatively comprehensive. The standard "flat-bottom vertical cylindrical cryogenic storage tank application" defines low-temperature tanks as three-tank, single-tank, double-container and full-container tanks according to different process requirements and medium storage methods. Single-container cans generally consist of a steel inner can and an insulated casing, while double-container and full-container cans are made of a steel inner can and a steel or concrete (usually prestressed concrete). The outer tank is composed of heat preservation between the inner and outer tank walls. At present, the double tank form is used more.

In the design of the cryogenic tank, due to the conduction of the low-temperature medium in the tank, the foundation soil is prone to freeze up and the soil is bulged, which causes the foundation damage. Therefore, in order to eliminate this unfavorable factor, in addition to the tank bottom plate and the base plate In addition to the insulation measures between the surfaces, it is necessary to take anti-freeze measures on the tank foundation. There are two common methods. One is to use electricity or other heating system in the base plate, that is, to make a see-saw foundation with a circulating heating system. The other is to use an air layer formed by overhead to separate the base floor from the foundation soil. The former is generally not used because of the high cost of the heating system. In most cryogenic tanks imported and built in China, an overhead raft foundation form is commonly used. The net height of the overhead layer is generally determined in addition to the process piping and equipment layout requirements, and is still determined based on the temperature of the storage medium in the tank. The overhead raft foundation can be divided into two types: single slab (cap) and double slab (cap). In the case of better geological conditions, the double raft foundation form can be used; The requirements for foundation settlement of tanks are relatively high. In most cases, especially on soft soil foundations with poor geological conditions, single rafters (caps) pile foundations are used, and sometimes double slabs are used. ) Pile foundation.