Specific role of low temperature storage tank

Steel sealed containers used to store liquids or gases are called steel cryogenic storage tanks. Cryogenic storage tanks are an important infrastructure in petroleum exploration, storage, transportation and processing. In recent years, with the rapid development of the Chinese petrochemical industry, the number of cryogenic storage tanks has increased rapidly. These cryogenic tanks have long been used to store crude oil, semi-finished products, hydrocarbons, corrosive or toxic chemical products.
 
During storage, moisture, salts, sulfides, and high-acid compounds contained in the above products are deposited on the bottom of the storage tank, causing electrochemical corrosion and perforation leakage of the bottom of the storage tank, and its safety has been widely recognized. Cryogenic storage tanks are usually stored with anticorrosive coatings.

In engineering practice, due to the influence of various factors, it is difficult for the anticorrosive cover to be intact, and corrosion often occurs at the place where the electrode cover is leaked or damaged, especially the corrosion of the bottom plate of the low temperature storage tank is extremely serious, which makes the anticorrosive cover resistant. The corrosion life is difficult to be consistent with the design life of the oil tank, and the low-temperature storage tank must be evacuated, cleaned, inspected, repaired, and recoated every 3 to 5 years. Not only does this have to stop work and production, causing economic losses, but also high maintenance costs and easy to pollute the environment. With the development of low-temperature storage tanks toward large-scale, long-life and environmental protection, more and more attention is being paid to it. It is urgent to find a long-life anticorrosive method that is both economical and effective and can meet environmental protection requirements. Developed foreign countries attach great importance to the anticorrosion work of low temperature storage tanks in the petrochemical industry, confirming that cathodic protection is economical and effective for the bottom protection of low temperature storage tanks. Cathodic protection technology has been widely applied to the outer bottom and inner walls of oil tanks.
 
Cathodic protection can make up for the lack of coating, make the steel plate with coating defects cathodic, and block the corrosion holes of low temperature storage tank materials. Good coating can also reduce the protection current and power consumption. Therefore, the cathodic protection layer and the cover layer can be used together to achieve better protection effect of the low-temperature storage tank.