35kg Aluminum Alloy Sacrificial Anode Bracket for Storage Tank Aluminum Anode

Bracket 35kg Aluminum Alloy Sacrificial Anode Storage Tank Aluminum Anode

Bracket 35kg Aluminum Alloy Sacrificial Anode Storage Tank Aluminum Anode How to Implement Effective Cathodic Protection for Storage Tanks:

1、Sacrificial anode cathodic protection involves connecting a metal with a more negative potential to the protected metal within the same electrolyte, allowing electrons to transfer from the anode to the protected metal, thereby maintaining the entire protected metal at a uniformly negative potential. This method is simple, easy to implement, requires no external power source, and rarely causes corrosion interference. It is widely used to protect small metal structures (typically with currents less than 1 ampere) or those in low soil resistivity environments (soil resistivity less than 100 ohm·m), such as urban pipeline networks and small storage tanks. According to domestic reports, there have been many failures with sacrificial anodes, with their service life generally not exceeding 3 years and at most 5 years. The main reason for the failure of sacrificial anode cathodic protection is the formation of a non-conductive hard layer on the anode surface, which limits current output. The primary cause of this issue is believed to be the anode composition not meeting specifications, followed by high soil resistivity at the anode location. Therefore, when designing a sacrificial anode cathodic protection system, it is essential to strictly control the anode composition and select an anode bed location with low soil resistivity.
2、Impressed current cathodic protection uses an external DC power source and auxiliary anodes to force current to flow from the soil to the protected metal, ensuring the protected metal structure's potential is lower than that of the surrounding environment. This method is mainly used to protect large metal structures or those in high soil resistivity soils, such as long-distance buried pipelines and large tank farms.

3、Cathodic protection is divided into sacrificial anode and impressed current methods. Storage tank cathodic protection is no exception and can use either sacrificial anodes or impressed current.
Using sacrificial anodes for tank protection involves the issue of shorter service life; once the anodes are consumed, replacement is troublesome. It requires breaking up the hardened ground around the tank to reinstall sacrificial anodes. Therefore, impressed current is generally used for storage tank cathodic protection, with anode bed materials typically chosen as MMO noble metal ribbon anodes or flexible anodes.

Bracket 35kg Aluminum Alloy Sacrificial Anode Storage Tank Aluminum Anode Storage Tank Cathodic Protection Potential

Cathodic protection for storage tanks generally uses impressed current. After construction is completed, the tank's potential can be displayed on the constant potential instrument panel. The principle is the same as for pipelines: one cable connects to the tank, and another connects to a reference electrode buried around the tank, allowing measurement of the tank's potential.

Potential measurement essentially measures the potential difference between the protected metal and the reference electrode. Since the reference electrode's potential is assumed constant, any change in the measured current is interpreted as a change in the structure's potential. However, this may not always be the case, as the reference electrode's potential could also change. Factors affecting the reference electrode include: Temperature effects: Generally, temperature increases can alter solution concentration, causing changes in the reference electrode potential and affecting its linearity. For common copper/copper sulfate reference electrodes, the temperature effect is approximately 0.9 mV/°C. For example, the typical potential measured for pipelines at around 26°C is -0.85V, while at about 5°C, it is around -0.825V. Therefore, when measuring crude oil storage tanks, the impact of crude oil heating should be considered. For portable reference electrodes, potential changes due to solar exposure (around 10 mV) should also be accounted for; wrapping the electrode with black tape can minimize this effect. Changes in the tank bottom plate can also affect measured potential, such as deformation or bulging due to crude oil heating. When the bottom plate warps, some areas may lose contact with the tank foundation, receiving insufficient protection current and leading to polarization. To avoid inaccurate measurements from this phenomenon, maintain the tank liquid level at about 2/3 for a certain period during measurement. Supplied by Jiaozuo Libo Light Alloy Co., Ltd.