How to deal with instrument corrosion? These 5 methods are worth keeping

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In the industrial production of the petrochemical industry, the corrosion of production equipment by various acidic and alkaline raw materials is a common phenomenon. The presence of corrosion undoubtedly has a negative impact on the service life of equipment as well as on production stability. If production efficiency can be improved through improvements in production processes and higher levels of equipment automation, it is possible to enhance the stable operation of the equipment while also effectively mitigating potential risks. Corrosion of chemical process instruments is one of the more common types of problems. There are various types of corrosion, and its causes are complex. If corrosion becomes severe and is not properly addressed, it can lead to reduced efficiency and lower quality in chemical production, disrupt the normal operation of such processes, and increase the risk of production accidents, thereby causing financial losses for chemical companies. Therefore, corrosion protection for chemical process instruments is crucial. Types of chemical process instruments: Chemical process instruments are one of the most widely used types of equipment in chemical production. They can detect and control variables such as temperature, pressure, flow rate, liquid level, and composition during the chemical production process, enabling automatic detection, display, and control. These instruments play a crucial role in ensuring the safety and stability of chemical production. First, we need to understand the classification of chemical process instruments. Based on the type of energy used, these instruments can be divided into electric chemical process instruments, hydraulic chemical process instruments, and pneumatic chemical process instruments. Based on the different measurement objects, they can be classified into temperature instruments, pressure instruments, flow rate instruments, level instruments, and analysis and detection instruments, which correspond to the five key parameters in chemical production. Based on their function, they can generally be divided into four categories: measuring instruments, indicating instruments, control instruments, and actuators. Common corrosion problems in chemical process instruments. Corrosion of chemical process instruments refers to the erosion and degradation of the metal or non-metallic materials that make up the components of these instruments, caused by physical, mechanical, chemical, or electrochemical effects; this phenomenon is collectively referred to as corrosion of chemical process instruments. The purpose of studying the corrosion prevention issues related to chemical process instruments is to identify the main factors causing corrosion in these instruments, as well as the solutions to such problems, by analyzing the types, mechanisms, and consequences of corrosion. Through experimental studies, it is possible to determine the factors that affect the performance of chemical process instruments used in chlor-alkali and allied alkali production processes, thereby improving the corrosion resistance of these instruments, ensuring the accuracy of measurements and controls, and enhancing production efficiency through automation. The main types of corrosion in chemical process instruments are electrochemical corrosion, chemical corrosion, and erosion of the instrument materials caused by physical and mechanical effects. Chemical process instruments used in chemical production are generally made of metal materials. They operate in complex environments characterized by high temperatures and pressures over extended periods of time, and they need to come into direct contact with various chemical substances. In an air-filled environment, it is very easy for them to come into contact with various ions present in the air or chemical media, leading to reactions that result in electrochemical corrosion of these instruments. Electrochemical corrosion of chemical process instruments is one of the most common and troublesome corrosion issues in chemical production processes; it is difficult to control and its treatment is complex. When chemical process instruments come into contact with free ions in the air or chemical substances, an electric current is generated on their surfaces, causing varying degrees of corrosion to the metal structure of these instruments, thereby affecting their proper functioning and reducing their service life. The electrochemical corrosion of chemical process instruments is based on metal materials, and the corrosion process is quite hidden, making it difficult for operators and maintenance personnel to detect it. Moreover, such instruments are hard to repair after corrosion occurs; therefore, it is necessary to take preventive measures to reduce electrochemical corrosion in these instruments. 1) Medium corrosion. Dielectric corrosion is the most common type of electrochemical corrosion. For example, the corrosion of instrument materials by acid, alkali, and salt solutions in chemical production processes. 2) Atmospheric corrosion. The essence of atmospheric corrosion is also a type of electrochemical corrosion. Its corrosion process occurs within a thin layer of condensation film on the metal surface; it mainly manifests as corrosion of the instrument’s electronic components, circuit boards, and connection wires, especially when the condensation film contains chloride salts and other substances. In the chemical corrosion process during chemical production, a variety of chemical materials are used. Most of these materials tend to react chemically with air or other substances, and they possess certain corrosive properties. The material composition of chemical process instruments mainly includes benzene derivatives and ethanol, etc., and the operating environments in which they are used are typically characterized by high temperatures and high pressures. In this situation, the chemical process instruments are exposed to high-temperature steam, which causes the chemical substances involved to gradually penetrate into the structure of the instruments. This leads to chemical reactions within those instruments, causing them to become increasingly hard and brittle, and they are slowly corroded until they become damaged and can no longer be used. During the normal operation of chemical process instruments, chemical corrosion is the most common type of damage. For example, in the chemical production of pyrite, the pyrite boils during the production process, resulting in the generation of large amounts of dry gas. These gases are extremely hot, and they can cause rapid and severe corrosion of the metal surfaces of the chemical process instruments, thereby affecting their proper functioning. However, this type of corrosion is often not given due attention and is easily overlooked. By the time corrosion issues are detected, the chemical process instruments have usually been severely damaged and can no longer be used; normal chemical production can only be resumed by replacing them. In addition to chemical corrosion, physical corrosion is also a common type of corrosion that occurs during the normal operation of chemical process instruments. This is because the materials used in the manufacture of chemical process instruments are quite special, and since they have to operate for long periods in high-temperature and high-pressure environments, they are susceptible to physical stress, which can lead to a decline in their performance as well as physical corrosion. Simply put, physical corrosion of chemical process instruments is the opposite of chemical corrosion; chemical corrosion occurs as a result of chemical reactions between the media used in chemical production and these instruments. Physical corrosion, on the other hand, occurs because chemical process instruments are exposed to high temperatures and pressures during normal use, which subject them to significant stress and thus lead to physical corrosion. Under normal circumstances, physical corrosion of chemical instruments occurs primarily in the production process of synthetic ammonia. This is because the synthesis of ammonia generates large amounts of high-temperature steam, which exerts significant physical pressure on the internal components of these instruments, thereby causing physical corrosion. As a result, the instruments may cease to function properly or get completely damaged, requiring prompt repair or replacement to avoid further problems and economic losses. Microbial corrosion in chemical production processes is highly complex. Most of the production equipment is sealed, the production areas are fixed, and the environment is complex, which facilitates the growth of certain microorganisms. The growth and reproduction of these microorganisms can also cause corrosion issues for chemical instrumentation. Furthermore, the fact that the internal spaces of chemical production equipment are not thoroughly cleaned over time, leading to severe scaling and contamination, can all contribute to the growth and development of microorganisms. An increase in the number of microorganisms accelerates the reproduction of bacteria and algae, disrupting the stable environment necessary for chemical production. This also has an impact on chemical instruments, and microbial corrosion is a problem that occurs from time to time and cannot be ignored. It is necessary to take effective measures for prevention and control based on the specific characteristics and causes of microbial corrosion, in order to restore a favorable production environment, reduce the corrosive effects on chemical instruments, ensure their proper functioning, and extend their service life. Methods for dealing with corrosion issues in chemical process instruments: Using materials with strong corrosion resistance. The reason why corrosion occurs in chemical process instruments is ultimately due to problems with their materials themselves. Today, chemical process instruments are usually made of metal materials, which are prone to corrosion. When in contact with chemical substances as well as materials under high temperature and pressure, the likelihood of chemical reactions increases, and these reactions become more intense, thereby exacerbating the degree of corrosion. Therefore, to fundamentally address the corrosion issue of chemical process instruments and extend their service life, it is necessary to start with the materials used in their fabrication by selecting appropriate anti-corrosion materials to replace traditional metal materials. This approach helps to reduce the corrosive damage caused by chemical production processes to these instruments, thereby saving on maintenance and replacement costs. When selecting materials for chemical process instruments, it is necessary to maximize their corrosion resistance. Such materials should be able to maintain stability when in contact with chemical substances as well as high-temperature and high-pressure environments, avoiding chemical reactions, electrochemical reactions, or physical reactions, thereby enhancing their corrosion resistance and reducing the occurrence of corrosion issues. Indeed, using materials with strong corrosion resistance in the manufacture of chemical process instruments can effectively prevent corrosion. However, when selecting materials for chemical process instrumentation, corrosion resistance alone cannot be the only consideration; the chosen materials must possess excellent properties, taking into account the manufacturing environment of the instruments, their cost, as well as the availability of such materials. The properties of the material are extremely important; its mechanical and physical properties, among others, have a decisive impact on the performance of the instrument. This is mainly due to the differences in the chemical components and their concentrations contained within them. Another factor is the careful analysis of the working environment for chemical process instruments, especially aspects such as humidity in that environment and the presence of corrosive substances; all of these factors can affect the service life of these instruments as well as their operational efficiency on a daily basis. Therefore, a comprehensive consideration is necessary. Applying a protective coating to instrument parts or components to form a protective layer is a very common anti-corrosion method in industry. Based on the material of the protective layer and the principles of its formation, they can be divided into the following three types: metal protective layers, including spraying, electroplating, hot-dip coating, carburizing, etc. Non-metallic protective coatings, such as paint, acid-resistant cement, rubber, plastic, enamel, etc ； Among these methods, applying anti-corrosion paint to chemical process instruments requires only a low cost. Moreover, this anti-corrosion painting can be repeated periodically – by applying more paint from time to time – thereby ensuring that the chemical process instruments remain in an optimal anti-corrosion environment over the long term. Therefore, even though applying anti-corrosion paint has certain limitations in use, it is still frequently employed for the anti-corrosion treatment of chemical process instruments; it is highly effective and reliable, and the treatment process is very simple. When applying anti-corrosion paint to chemical process instruments, it is essential to strictly control the selection of the anti-corrosion paint as well as the application process, in order to minimize any impact that the application of this paint may have on the normal operation of the instruments, on their performance, or on the chemical production processes. Non-metallic protective films are formed by chemically treating metal surfaces to create protective layers such as oxide films and phosphate films. Strict control of microbial counts is necessary; chemical process instruments can be damaged by microorganisms during use, leading to corrosion, and this corrosion can be controlled through appropriate preventive measures. The specific approach is to strictly control the microbial population in order to prevent these microorganisms from corroding chemical process instruments. Chemical process instrument maintenance personnel need to regularly measure the levels of key microorganisms such as heteroxygenic bacteria and other types of bacteria. When abnormal levels of these microorganisms are detected, it is necessary to administer chemicals promptly to eliminate them. The dosage and type of chemicals used should be adjusted based on the species and quantity of bacteria, while ensuring that normal operations of chemical production are not disrupted. A viable approach must be developed through rigorous theoretical analysis and scientific experiments in order to reduce the corrosive damage caused by microorganisms to chemical process instruments. Strengthen the management of the use of chemical process instruments. The use of such instruments must be carried out in strict accordance with the relevant operating procedures, which helps to reduce the likelihood of corrosion issues occurring. Surface corrosion of chemical process instruments can be repaired and reversed; the impact it causes is minimal, and it is possible to restore them to use by replacing the casing. If corrosion occurs inside a chemical process instrument, it can lead to serious consequences, damaging the various electronic components and chips within it; normal operation can only be restored by replacing the entire instrument, which is costly. Therefore, it is necessary to strengthen the management of the use of chemical process instruments, and to make effective preventive and corrective decisions in response to the corrosion problems that commonly occur with such instruments in chemical production. The operating environment for chemical process instruments used in isolation tasks is highly complex; therefore, no matter what anti-corrosion material is chosen, certain chemical, physical, and electrochemical reactions will inevitably occur during actual use, and the problem of instrument corrosion cannot be completely eliminated. Therefore, in order to extend the service life of chemical process instruments as much as possible, it is necessary to carry out isolation measures based on the actual operating environment and performance characteristics of these instruments, thereby reducing the likelihood of corrosion. Firstly, chemical enterprises can use monitoring instruments such as radioactive, ultrasonic, and optical radiation devices; this approach completely prevents the instruments from being corroded or damaged by the medium involved, but it is costly, and subsequent maintenance is also more complicated. . Secondly, the use of isolation devices, isolation diaphragms, isolation fluids, and other isolation measures can isolate the sensing part of the instrument from the medium, thereby achieving corrosion protection. Isolation corrosion protection is an effective method for protecting instruments from corrosion. Depending on the actual operating conditions and the requirements of measurement and control, we can employ methods such as using isolation fluids, blowing air, or applying protective layers to effectively prevent or reduce corrosion of the instruments.