Regional cathodic protection for large storage tank area and buried pipe network

Cathodic protection has been proved to be an effective method of corrosion control. The cathodic protection of large oil depots and storage tanks in foreign countries has been implemented compulsively, and the cathodic protection system and the main project have been designed, constructed and put into operation at the same time, and good results have been obtained. For example, in 1988, the United States Environmental Protection Agency (EPA) formulated a technical regulation expressly requiring the addition of necessary cathodic protection measures to prevent corrosion and pollution to approximately 3 million existing storage tanks in the United States by the end of December 1998. For buried, partially buried and submerged metal structures. Cathodic protection technology for storage tanks started relatively late in China, and there are still many storage tanks and pipelines without cathodic protection.

Cathodic protection methods for oil storage tanks are generally as follows:

(1) Impressed current cathodic protection for shallow buried anode around tank

(2) Deep well anode impressed current cathodic protection around tank

(3) Around the tank magnesium alloy/zinc alloy sacrificial anode cathodic protection

(4) anode impressed current/sacrificial anode cathodic protection of tank bottom inclined well

(5) tank bottom linear anode (magnesium strip/mesh anode) cathodic protection, etc

However, some of the above cathodic protection methods are only applicable to new storage tanks, such as tank bottom linear anode (magnesium strip/mesh anode) cathodic protection; Some can only be protected for a single tank, such as shallow buried anode cathodic protection around the tank; Some economy and protection effect is not ideal, such as tank sacrificial anode cathodic protection; Some of the construction is difficult, such as tank bottom inclined anode. In a large storage tank area, there are many storage tanks and the network connected with them is complicated. If effective protection is needed, the above several cathodic protection methods should be considered comprehensively, and some protection methods should be longer than others, so as to complement each other's advantages. This is the regional cathodic protection technology.