Anti-corrosion Measures for Chemical Process Pumps
Speaking of chemical process pumps, they are more and more widely used in industrial production, especially in the chemical field, corrosion-resistant chemical process pumps are increasingly playing an important role. Under normal circumstances, due to the particularity of the environment in which chemical process pumps are used, they are generally made of metal or fluoroF46. For ordinary metals, their structure is extremely prone to corrosion, and the external environment such as temperature, humidity and air It will directly lead to metal corrosion, so our common materials for corrosion-resistant chemical process pumps are stainless steel and fluoroplastic F46.
The medium suitable for chemical process pumps is basically corrosive, and for the classification of corrosion, there are generally two classification methods.
The mechanism is classified, and the other is classified according to the cause and appearance of corrosion. According to the mechanism of corrosion, it can be divided into electrochemical corrosion and chemical corrosion. Electrochemical corrosion mainly refers to the phenomenon of corrosion caused by the electrode reaction on the surface of the metal material after it comes into contact with the electrolyte solution. This reaction is generally a redox reaction, and the main factors are the humidity and temperature of the environment; Chemical corrosion refers to a relatively strong chemical reaction between the metal surface and the surrounding medium, which causes the metal to be damaged to a certain extent. The main reasons for this corrosion are high temperature and dry environment. According to the appearance and causes of corrosion, it can be divided into peeling corrosion, industrial atmospheric corrosion, high temperature oxidation corrosion and marine atmospheric corrosion.
In the environment with serious industrial pollution, because there are more volatile substances such as sulfide, carbon dioxide and hydroxide in the air, and also contains some industrial dust, these are media that are easy to cause corrosion. When these media are in a humid environment, the acid gas will combine with water to form inorganic acids. These acids have strong corrosive properties, so they will induce corrosion. In the environment of industrial atmosphere, equipment is caused by the combined effect of electrochemical corrosion and direct chemical corrosion. The essence of all corrosion is actually an oxidation process in which metal elements lose electrons to form ions. The main difference between electrochemical corrosion and industrial atmospheric corrosion is the different environments in which they occur.
The corrosion of equipment is closely related to the materials of the equipment. In the selection process of chemical materials, we should focus on the occurrence of corrosion, pay attention to the reasonable selection of materials, and fully consider the properties of the medium, the temperature of the environment and the operating pressure, etc. According to the chemical industry The requirements of raw materials and the structure and type of design equipment. The design of the structure should focus on the production requirements and stress characteristics in the production and operation of chemical equipment, and the following aspects should be paid attention to in the design: first, the structural requirements of the product should be consistent with the corrosion resistance requirements of the production of chemical products; secondly It is necessary to pay attention to the operation stability and smoothness of chemical equipment, to prevent the suspension of corrosive media, the uneven distribution of heat load, the condensation of steam and the accumulation of corrosion products; finally, it is necessary to pay attention to the protection of external forces to prevent Fatigue corrosion caused by alternating stress.