Dry Replacement Technology for LNG Gas Storage Tanks

After the low-temperature LNG enters the storage tank, the part with water will condense into ice immediately, and the secondary bottom plate will be lifted up, thereby damaging the structure of the inner tank; in addition, the expanded perlite filled between the inner and outer storage tanks will also agglomerate , which seriously affects the cooling effect of the storage tank. The tank’s auxiliary piping and low-pressure pumps may also freeze, which can affect the operation of the tank. Therefore, the dry replacement treatment must be carried out after the hydrostatic test before it can be put into production. Next, let’s talk about the dry replacement technology of LNG Gas Storage Tanks.

Tank Structural Partitioning

A complete LNG Gas Storage Tanks consists of a concrete outer tank and an inner tank. The spacing between the inner and outer box walls is typically about 1 m, forming an annular space. Between the inner box bottom and the outer box bottom is the box bottom cold insulation layer, which can also be used as part of the annular space. The top of the liner has a suspended ceiling that acts as a support for cold insulation to reduce heat transfer and reduce LNG evaporation. The space between the suspended ceiling and the external storage tank is called the tank headspace. The space formed by the ceiling, the inner wall and the bottom of the inner bladder is called the inner bladder space.

Requirements for dry replacement of LNG Gas Storage Tanks
Fundamentals of Nitrogen Drying and LNG Gas Storage Tanks Replacement

The drying and replacement of LNG Gas Storage Tanks generally adopts two methods: continuous drying and replacement or pressure expansion. The former means that the amount of nitrogen charged during the displacement process remains the same as the amount discharged, keeping the storage tank in the tank during the displacement process. The pressure is basically unchanged.
The pressure expansion type means that the exhaust valve of the storage tank is closed first, nitrogen is filled into the storage tank at a certain pressure, the nitrogen filling is disconnected, the exhaust valve of the storage tank is opened to release the pressure, the pressure is reduced to a certain pressure, and then closed and discharged. port, open the nitrogen inlet to inflate, and then repeat the operation.

Wuxi Hansheng Pressure Vessel Industrial Co., Ltd  is a manufacturer of cryogenic storage tanks, lng storage tanks, lng gas filling station equipment, cryogenic liquid transport vehicles, natural gas storage tanks, lng tankers, liquid nitrogen storage tanks, carbon dioxide storage tanks, cryogenic liquid nitrogen transport vehicles, and we produce cryogenic liquids With its advanced technology, excellent quality and excellent after-sales service, equipment such as storage tanks, tank cars, tank containers, and low-temperature insulating gas cylinders are widely accepted by many famous gas companies at home and abroad. Welcome to consult.

Post time: May-11-2022

Send your message to us:

Write your message here and send it to us