Anticorrosion measures for pressure vessels in industry

Pressure vessel plays an important role in chemical production. However, in the actual operation process, due to the influence of operating conditions such as medium, temperature and pressure, the pressure vessel will produce damage and corrosion. Due to metal corrosion, the normal operation of the system in actual production is seriously affected. Therefore, it is very important to protect the corrosion of pressure vessels in chemical production.

The corrosion phenomenon of metal is mainly due to the alloy, metal and impurity contained in the metal of casting pressure vessel. These internal factors interact with external temperature, solution concentration, pressure and liquid flow rate under the condition of complex interaction. The metal will be corroded. First of all, the chemical properties of the metal itself should be considered. Some metals with active chemical properties are easy to be corroded. Through a lot of research and comparison, as well as the summary of production experience, the corrosion rate of pressure vessel is closely related to the amount of alloy contained in it, and the impurities in the metal will accelerate the corrosion rate.

In addition, the metal state and crystal form on the surface of the pressure vessel have a great influence on the corrosion of the vessel. The smoother the surface of the vessel is, the less the corrosion will be, on the contrary, it will be easy to be corroded; adding oxide film on the surface of the vessel can improve the corrosion resistance of the vessel.

There must be a lot of corrosive substances in chemical production, such as acids, alkalis and salts, including water and oxygen, which constitute the external environment of pressure vessels.

Metal materials have a certain range of resistance to corrosive media. Therefore, when using pressure vessels, it is necessary to fully consider the chemical composition of the external environment medium and the concentration, type, pH value of the medium as well as the moisture content, oxygen content and impurity content in the medium.

Corrosion inhibitor can effectively slow down the occurrence of corrosion phenomenon and reduce the degree of corrosion, with high economic benefits and anti-corrosion effect. It is one of the most effective and widely used technologies in improving the corrosion resistance of pressure vessels. Corrosion inhibitor is essentially a kind of chemical mixture, which can effectively slow down or even prevent the occurrence of corrosion after being applied on the metal surface. The general dosage of corrosion inhibitor is a few parts per million, some are increased to a few thousand percent, and according to different requirements, in some cases to a few percent. According to the actual use, it can be concluded that adding a small amount of the chemical mixture into the metal material can effectively reduce or reduce the corrosion degree of the medium to the metal to zero, and at the same time keep the physical properties of the metal unchanged.

The electrochemical protection method is based on the electrochemical principle in metal equipment to take measures to make it become the cathode in the corrosion battery, so as to prevent or reduce metal corrosion. There are two kinds of sacrificial anode method and external current method. The sacrificial anode method uses the metal or alloy whose electrode potential is lower than the protected metal in the pressure vessel as the anode and fix it on the protected metal to form corrosion Corrosion electrode, protected metal as cathode. Aluminum, zinc and their alloys are commonly used as sacrificial anode materials. This method is often used to protect various metal equipment and components in industrial water and to prevent corrosion of giant equipment such as oil tanks and oil pipelines. The applied current is to use the protective metal as the cathode of another battery and connect with the additional electrode through the way of additional battery. Under the action of external direct current, the protected metal can be effectively protected. This method is mainly used to protect the metal in soil and river water from external environment corrosion.

Shandong Linyi Bosi conductive materials Co., Ltd. is a high-tech enterprise specializing in the production of MMO flexible anode, conductive polymer flexible anode and titanium coated anode, mainly providing cathodic protection technology, engineering design, installation and technical services. 

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