Analysis of Common Causes of Corrosion in Petrochemical Equipment and Practical Anti-corrosion Strategies

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With the rapid development of the petrochemical industry, corrosion of petrochemical equipment during actual operation is becoming increasingly severe. This not only poses a direct threat to the health of the equipment operators but also reduces the service life of the equipment, which is detrimental to the production of higher-quality chemical products. Therefore, in order to better address the corrosion problem of petrochemical equipment, it is necessary to analyze and study the common causes of corrosion, and to develop corresponding anti-corrosion measures. By implementing anti-corrosion measures in a scientific and rational manner, it supports the longer-term operation of equipment and provides a fundamental basis for the efficient development of the petrochemical industry. Figure 1.1 Ensuring the proper operation of equipment. In actual petrochemical production, equipment corrosion has always been one of the major problems that affect manufacturing processes. Since corrosion is a very common issue and its treatment is relatively complex, few companies are able to carry out effective anti-corrosion measures. Additionally, corrosion issues only arise under certain conditions; once they occur, they can affect the operation of the equipment and also hinder the smooth progress of other tasks in the vicinity, thereby shortening the equipment’s lifespan. By carrying out anti-corrosion treatments effectively, it is possible to help enterprises establish the correct concepts and methods for anti-corrosion work to a certain extent, and to guide them in carrying out such work in a scientific and rational manner. This not only ensures the effectiveness of anti-corrosion measures but also guarantees the continuous and normal operation of the equipment, which plays a very positive role in safeguarding the economic benefits of the enterprise. 1.2 Effective implementation of safe production: In the process of producing chemical products using petrochemical equipment, corrosion in certain parts of this equipment can directly affect the quality of the products. Moreover, issues such as gas and liquid leaks resulting from corrosion can compromise the safety of the personnel involved in the production process, which is highly detrimental to achieving the goals of safe production. Furthermore, corrosion can also lead to leaks of petroleum raw materials, and when exposed to an open flame, it can cause extremely severe explosion accidents, severely affecting the production of chemical products as well as the safe operation of personnel and enterprises. By carrying out effective anti-corrosion measures, it is possible to prevent these problems from occurring in the first place, effectively address equipment corrosion, and ensure that the entire production process can proceed smoothly and safely. This not only helps to facilitate more efficient production processes, but also provides a basic level of protection for people’s health and safety. 1.3 Achieving efficient environmental protection: Once corrosion occurs, it not only has a direct impact on a company’s production efficiency and leads to reduced economic profits, but it also forces the company to assume considerable responsibility for environmental pollution. This is mainly because corrosion issues can lead to leaks of semi-finished products and raw materials within the equipment; the harmful gases or liquids that leak out can enter the natural environment through the soil and drainage systems, thereby affecting the local ecological environment. Proper corrosion protection of equipment is a method to prevent environmental pollution at its source; it helps to avoid leaks of gases or liquids, ensuring that waste gases and liquids are treated in an environmentally friendly manner before being released. This not only helps to prevent severe waste of resources by enterprises, but also enables effective protection of the surrounding ecological environment. 2 Common causes of corrosion in petrochemical equipment
2.1 Equipment-related issues
During the actual production and processing of chemical products, a wide variety of equipment is utilized, including reaction vessels, heat exchangers, heating equipment, storage tanks, and instrumentation devices. Most of these equipment items are made of various types of metals. When metals are exposed to air for an extended period of time, they undergo oxidation reactions with various substances in the air, resulting in corrosion. Additionally, due to the highly complex structure of chemical processing equipment, the process of preventing corrosion and oxidation becomes very complex and prone to changes. At the same time, if reactive metals are present in chemical processing equipment, electrochemical reactions occur upon contact with electrolytes, leading to electrochemical corrosion. Preventing this type of corrosion is extremely difficult; once it occurs, it has a serious impact on metal components. Not only can the components be damaged, but material leaks may also lead to short circuits in electrical equipment and problems with temperature control, and in severe cases, explosions may occur. 2.2 Chemical Reactions In the daily operational processes of petrochemical enterprises, it is necessary to use equipment to handle various types of media, and numerous chemical reactions occur during this process. The main chemical reactions that commonly cause corrosion problems are as follows: First, acid and alkali media are common types of substances that readily lead to corrosion in equipment, and they can react with metal components. Second, various materials or reagents need to be added during production; some of these materials react with each other. Moreover, certain media release significant amounts of heat or high-temperature gases during chemical reactions, and all of these can cause oxidation reactions with the equipment, leading to its corrosion. Thirdly, the production environment is also an important factor that causes equipment corrosion. This is mainly because in most workshops where petrochemical products are manufactured, there are various metal particles, chemical solutions with different pH levels, and corrosive gases. If equipment remains in such an environment for an extended period of time, it will suffer from corrosion. Fourth, during the production process, some of these solutions do not react with the equipment at the beginning of their formation; however, once the temperature rises to a certain level, these solutions undergo redox reactions with the metal equipment, resulting in corrosion of the inner surfaces of the equipment. Fifth, in production, different types of chemical corrosion occur in various regions; for example, production equipment in coastal areas is subject to long-term erosion by chloride ions. 2.3 Physical corrosion: In traditional petrochemical production processes, the flow of gases and liquids can also cause certain levels of corrosion to chemical processing equipment. Generally, this problem is caused by improper human operation; for example, in actual operations, operators fail to pay adequate attention to the proper maintenance and protection of the equipment, which results in too fast flow rates of gases and liquids during production, leading to erosion and corrosion of the equipment or pipelines. Generally, the higher the flow rate, the greater the surface area of the material in contact, and thus the faster the rate of corrosion of that material. Therefore, if attention is not paid to the actual capacity of the equipment, and the flow rate of gas and liquid within it is too high, this will lead to gradual corrosion of the metal components. Additionally, since some employees do not have a proper awareness of safe production practices and do not pay sufficient attention to tasks such as equipment inspection and maintenance, the degree of corrosion worsens over time; in severe cases, the equipment may become irreparable, causing significant economic losses for the company. 3 Anti-corrosion measures for petrochemical equipment 3.1 Isolating corrosive agents In the actual process of carrying out anti-corrosion work, in addition to using appropriate methods for repair and treatment, it is very important to address the corrosion problem at its root; this represents the most effective approach for anti-corrosion. Given that the equipment is prone to corrosion by chemical media, it is currently necessary to control the concentration of such chemicals in order to effectively isolate them from the equipment. By improving the environment in which the equipment is located, better corrosion protection can be ensured. Firstly, for petrochemical equipment, it is necessary to keep it as far away as possible from corrosive substances such as seawater. This can be achieved by applying an anti-corrosion coating on the surface of the equipment, thereby isolating it from seawater and preventing prolonged corrosion that could affect the quality of the equipment. Secondly, it is possible to appropriately control the medium concentration; by means of dilution and other methods, corrosion of equipment caused by high-concentration media over extended periods can be reduced, while ensuring the normal operation of the enterprise. At the same time, since most of the equipment and pipelines used in petrochemical plants are exposed to corrosive substances, and the concentration and temperature of these substances often change, it is necessary to select appropriate anti-corrosion measures based on the actual conditions. For certain media that are susceptible to corrosion only when the temperature rises, and in cases where it is not possible to control the temperature of such media, emphasis must be placed on isolation measures applied to the equipment itself, such as applying isolation coatings. 3.2 Scientific Selection of Equipment At present, research on the corrosion protection of petrochemical equipment in China is advancing rapidly. Building on the materials traditionally used for such equipment, many new corrosion-resistant materials with superior properties have been developed and are now being applied in the production and manufacturing of chemical equipment. It mainly involves using various corrosion-resistant materials to create linings for the equipment or to add protective coatings on it, thereby completely separating the metal components from the medium and preventing severe corrosion of the equipment. This improves the equipment’s resistance to corrosion and wear, effectively extending its service life. There are certain differences between the anti-corrosion coatings used in chemical plants and conventional coatings; they require a relatively high level of technical expertise, have strong acid and alkali resistance due to their specialized chemical components, and involve many new technologies and recent research developments. Therefore, in the actual process of selecting production equipment, in order to better support the orderly production of chemical products, it is necessary to pay close attention to the selection of equipment used in actual production. It is not only important to choose equipment with good corrosion resistance and high durability, but also to consider the use of various new materials, especially those that are environmentally friendly and resistant to corrosion. This ensures that environmental protection equipment can be applied in actual production, thereby extending the lifespan of the equipment and contributing to environmental protection and energy conservation. Furthermore, the production of anti-corrosion coatings used in chemical plant equipment relies on the integration of knowledge from various disciplines such as physics, ecology, instrumentation, and mechanics. The relevant technologies stem from the synthesis of highly resistant resins, the use of rheology modifiers and efficient dispersants, as well as the development of new types of anti-corrosive and impermeable pigments and fillers. From this perspective, the development of materials and technologies for anti-corrosion equipment in chemical plants can also ensure an effective level of corrosion protection to a certain extent. Therefore, as the main users of such equipment, it is necessary to pay attention to the emergence and application of new anti-corrosion materials. Based on actual circumstances, they should actively purchase new equipment to support effective anti-corrosion measures and to help improve the anti-corrosion performance of chemical processing equipment. 3.3 Strengthening technical management: To address the various factors that cause corrosion in chemical processing equipment, the simplest and most direct approach is to apply anti-corrosion coatings on the outer or inner surfaces of the equipment, or to use corrosion inhibitors, while also enhancing the management of anti-corrosion technologies. This allows for a good anti-corrosion effect in the shortest possible time, and compared to purchasing new equipment, this method is also less costly. In the actual use of chemical processing equipment, in order to ensure the overall quality and standard of the products produced, it is necessary to exercise strict control over the specific application of each component of such equipment. Given that chemical production in enterprises inherently involves numerous safety risks, the issue of equipment corrosion may seem relatively minor. However, if not given sufficient attention, it could lead to serious safety accidents. Therefore, in actual production, it is necessary to ensure that the concept of safe production is applied throughout the entire production process. Strict management systems should be employed to oversee production operations, and thorough cleaning and maintenance of equipment must be carried out to enable problems to be identified and addressed promptly. At the same time, it is necessary to carry out proper maintenance of the equipment; a specialized department for equipment inspection and repair should be established within the company, tasked with regularly checking for signs of corrosion on the equipment, and formulating targeted solutions based on the actual condition of the equipment. Ensure that more professional anti-corrosion techniques can be employed to support the safe operation of the equipment. During the actual maintenance process, the anti-corrosion plan involving desalination and four types of injection can be implemented. Specifically, by employing desalination, water injection, alkali, ammonia, and corrosion inhibitors, the equipment’s resistance to corrosion can be enhanced, thereby effectively mitigating corrosion issues. This method has been used by foreign companies since the 19th century, and in recent years China has continuously improved it through practical application, achieving good results. In practice, the use of chloride-based substances can effectively alleviate the problems related to corrosion caused by the condensation cooling system during equipment operation ； Through deep desalination, the concentration of corrosive media is effectively reduced, achieving better anti-corrosion effects. In addition, it is necessary to regularly assess the technical skills and professional capabilities of personnel. Relevant equipment maintenance staff should be guided in a timely manner to participate in various new anti-corrosion technology training programs, so they can acquire and understand more anti-corrosion methods and apply them in their actual work. By strengthening various aspects and implementing efficient technical management, technical support is provided to ensure the safer operation of equipment. 4 Conclusion In summary, petrochemical equipment is a very important component of chemical enterprises, and its quality and efficiency can directly affect the profitability of these enterprises. Given the current serious problem of corrosion, in order to implement anti-corrosion measures more effectively, it is necessary to identify the main causes of equipment corrosion. By isolating corrosive substances, selecting appropriate equipment, and implementing proper technical management, these anti-corrosion measures can be put into practice. This approach ensures better corrosion resistance, prevents environmental pollution caused by chemical leaks, and avoids safety hazards in production. By ensuring production safety, it also helps companies achieve maximum efficiency.