What to do about corrosion in liquid chlorine vaporizers?

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Current issues: Studies in Japan’s chemical industry show that corrosion is responsible for 54% of equipment failures. DuPont in the United States analyzed the causes of equipment damage over several decades within its company and found that corrosion was responsible for more than 50% of such cases. According to corrosion surveys conducted in China on 20 major chemical industries such as oil extraction, refining, power generation, chemicals, and the automotive industry, the country’s annual corrosion losses exceed 500 billion yuan. For many chemical companies around the world, preventing losses caused by failures in process equipment due to corrosion has become an urgent issue. Classification of corrosion in liquid chlorine vaporizers Liquid chlorine vaporizers are key equipment in the chlor-alkali industry, and their function is to convert liquid chlorine into gaseous form. Liquid chlorine has a wide range of applications in gasification; as a strong oxidizing agent, it is primarily used in industries such as the paper industry, tap water purification, textiles, and metal refining. The corrosion of liquid chlorine vaporizers can be classified into the following categories: (1) Pitting corrosion. Pitting corrosion is a type of localized corrosion that occurs on the metal’s passivation film. If the rate of regeneration of the passivation film is not fast enough, this corrosion will accelerate, leading to an increased depth of corrosion. This type of corrosion generally occurs easily in aqueous solutions containing halides (such as chlorides). (2) Crevice corrosion Among various types of corrosion, crevice corrosion is the most common. Crevice corrosion can occur between different materials as well as within the same material. It appears in the form of cracks, and crevice corrosion arises when the oxygen supply is insufficient, leading to the breakdown of the passivation film. An effective way to prevent such corrosion is to increase the content of chromium and molybdenum in the alloy, especially molybdenum. (3) Stress corrosion cracking: Stress corrosion cracking is a type of corrosion in which cracks occur in metal materials under the action of tensile stress and specific corrosive environments. The appearance of cracks is often unpredictable, and there are no obvious changes visible in the corroded components. The conditions for stress corrosion cracking to occur are: ① the effect of other types of corrosion, such as pitting or crevice corrosion ； ② This specific medium is present in corrosive environments ； ③ The surface of the component is subjected to tensile stress (including internal stress) exceeding the critical value ； ④ The material is sensitive to specific media that cause stress corrosion. Repair methods for corrosion of liquid chlorine vaporizers. To address the corrosion issue in liquid chlorine vaporizers, traditional solutions often involve disassembly, welding repairs, or blocking the pipes; however, these methods do not resolve the underlying problem and instead reduce the efficiency of the vaporizer. In the end, significant costs are required to replace the damaged components with new ones. To address such issues, the Sorey series of polymer composite anti-corrosion coatings can be used for repair and protection. They can be used safely in enclosed environments without shrinking, and their excellent ability to prevent bimetallic corrosion along with their strong resistance to erosion ensure that corrosion and leakage at the repaired areas are completely eliminated, providing a long-lasting protective coating for the components. Polymer composite anti-corrosion coatings possess excellent adhesion, corrosion resistance, and heat tolerance, enabling them to effectively address such issues, extend the service life of equipment, and ensure safe and continuous production for enterprises.