This article analyzes and discusses the common anti-corrosion problems in the petrochemical industry, introduces the corrosion types of commonly used instruments, and proposes different anti-corrosion measures based on different corrosion types. By applying a series of anti-corrosion measures, the damage of corrosion to equipment can be greatly reduced, and at the same time, the workload of operators and maintenance personnel can be reduced, the maintenance funds invested by enterprises can be lowered, the production efficiency of enterprises can be improved, and considerable economic benefits can be brought to enterprises.

The anti-corrosion problem of chemical instruments is an unavoidable issue. Through the efforts of various research institutes, professional researchers, and enterprise engineers, many corrosion-resistant materials have been developed and put into practical use, including metal materials, non-metal materials, and alloy materials. These materials play an important role in anti-corrosion protection of measuring instruments in production activities.

1、 Corrosion types of chemical instruments

Before introducing various anti-corrosion methods, let's first introduce the concepts and different types of corrosion that exist in chemical production.

Corrosion refers to the physical and chemical reactions between metals and moisture and gases in the external environment, which cause changes in the surface and internal properties of metals, resulting in damage to the functional structure of metal materials or other components. In the petrochemical industry, chemical instruments and their components are prone to physical, chemical, and electrochemical reactions when in contact with the external environment, resulting in damage to chemical instruments and their components. Transmitters are commonly used in industrial sites as front-end acquisition and detection devices. The oil sensor of the transmitter consists of a loosening plate and connecting wires, all of which are made of precious metals to improve the detection accuracy and sensitivity of the equipment. These devices are exposed to harsh environments in industrial sites, causing corrosion. Common types of corrosion include:

1. Physical corrosion

External mechanical forces can cause damage to metal materials, as well as physical dissolution of metal materials, which can lead to physical corrosion of chemical instruments.

2. Chemical corrosion

Instrument metal materials are prone to oxidation-reduction reactions when in contact with gases in the external environment, and non electrolyte solutions can cause oxidative corrosion when in contact with metal materials, all of which belong to chemical corrosion of chemical instruments. The toxic gas chlorine produced by chemical plants and the iron element in instrument components undergo oxidation-reduction reactions to produce ferrous chloride, causing instrument corrosion.

3. Electrochemical corrosion

The most common corrosion that occurs in chemical instruments is electrochemical corrosion. In the chemical environment, there are common corrosive substances such as strong acids and bases. When the metal materials of chemical instruments come into contact with electrolyte solutions, the principle of primary cell reaction occurs, and the active metal materials with strong reducibility lose electrons and are oxidized. Steel materials are more susceptible to corrosion in humid air because the surface of the steel reacts to produce electrolytes. The electrolyte solution forms a primary battery device with the iron and carbon in the steel, causing the iron element to lose electrons and be oxidized. Many metal substances are damaged by electrochemical corrosion. Electrochemical corrosion can corrode the surface and internal components of instruments in a short period of time, and the sediment caused by corrosion can affect the accuracy and precision of instruments.

2、 Instrument anti-corrosion methods

With the existence of corrosion problems, anti-corrosion problems arise. In production, corrosion and anti-corrosion are like a pair of constraints. In the petrochemical industry, a large amount of corrosive substances are produced in the production process of enterprises. The corrosion phenomenon of the detection instruments used in the process is severe, which greatly reduces the service life of the instruments. In the actual production process, the presence of corrosion causes frequent instrument failure rates. Enterprises often replace instruments to ensure the normal operation of production equipment, thereby increasing their operational and maintenance costs. The widely used anti-corrosion methods in the chemical industry include isolation method, anti-corrosion material method, development of anti-corrosion sensors, installation of anti-corrosion valves, etc. Among them, isolation method is the most commonly used. For example, when using anti-corrosion electromagnetic flow meters to measure acidic and alkaline media, isolation materials such as polytetrafluoroethylene and PP are used.