How is corrosion protection carried out for pipes and equipment in newly built chemical plants?
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As title: 1. What measures are required for the external anti-corrosion of pipelines and equipment? I saw them applying a layer of light blue paint over the original pipe (which has been painted red). So, what about the welds and joint areas? Then insulation was applied. 2. A layer of silver powder was painted on the exposed pipes and equipment – what is the purpose of that? 3. What types of pipes and equipment require internal anti-corrosion treatment, and how is this treatment carried out?
Question 1: That is when construction workers apply anti-rust treatments to weld seams in ordinary pipes, usually referring to water supply pipes, steam pipes, cooling water pipes, etc. Question 2: Applying silver powder to pipes is done to make them look more attractive; this is generally used in TIG welding, mostly after welding stainless steel pipes. Question 3: If your company doesn’t have acidic media, then there is no need for pipeline anti-corrosion measures; generally, 304 material is sufficient. For conveying media such as nitric acid, acetic acid, phosphoric acid, sulfuric acid, hydrochloric acid, etc., PTFE, also known as tetrafluoroethylene, is used as a lining in the pipes. I hope the above will be helpful to you! ! !
1. Typically, two coats are required – a primer and a topcoat – as specified by the painting rules; in this case, red is used as the primer and blue as the topcoat, while only a primer is applied to the insulated areas. The welded parts are treated in the same way. 2. In accordance with clause 3.3.6 of HG/T20679, painting static equipment such as towers, heat exchangers, and storage tanks in silver-white is primarily a requirement related to coloring. The heating pipes and radiators are coated with aluminum powder, mainly for corrosion protection and aesthetics. Now, many storage tanks are coated with cool insulation glue, which is white in color and serves mainly to insulate the equipment. 3. For applications with high corrosivity, in order to reduce costs, pipeline materials are chosen; various internal anti-corrosion measures such as rubber lining and glass lining were commonly used in the 1960s and 1970s (due to a shortage of stainless steel materials in China at that time), but they are used less frequently nowadays. Because internal anti-corrosion measures are ultimately complex to implement and have a relatively short lifespan. Today, materials resistant to corrosion are generally used, such as acetate and zirconium; other materials include various alloys like Hastelloy, as well as different stainless steel grades such as duplex steel, 304, and 316.
1. What measures are required for the external anti-corrosion of pipelines and equipment? I saw them applying a layer of light blue paint over the original pipe (which has been painted red). So, what should be done regarding the welds and joint areas? Then insulation was applied. The pipes were treated with anti-corrosion measures before installation, and spaces at the welds were taken into account. If conditions permit, it is best to use primer, along with intermediate and top coats; however, this requires additional protective measures during construction to prevent damage. The paint on the welds and joints should be applied only after leak-free testing has been completed. The application procedure involves first removing rust, followed by applying the primer, intermediate coat, and topcoat. A layer of silver powder has been applied to the exposed pipes and equipment – what is the purpose of this? The color of pipeline equipment should be applied in accordance with relevant standards and the company’s own color coding requirements; for example, water pipes are painted green, fire protection pipes are red, pipes used for general process fluids are silver, and those used for acids are purple, all to facilitate identification. u: Z' N8 Q$ X5 f 3. Which types of pipes and equipment require internal anti-corrosion treatment, and how is such treatment carried out? This design will determine whether the medium has an corrosive effect on the material; in such cases, internal anti-corrosion measures are necessary. For example, in desulfurization towers, corrosion-resistant materials or fiberglass-reinforced plastics can be used for the pipes. The choice depends on investment considerations and process requirements, and there is no one-size-fits-all solution.
What are the colors of the primer, intermediate coat, and topcoat respectively? Is the primer red? What is that blue paint? Why do I only see the colors of two paints?
In China, it seems that red primers are used on carbon steel pipes or iron plates, with the purpose of preventing rust. If what you see is blue paint on a red primer, then that is the topcoat. There’s no fixed rule regarding this; you can choose the color according to your needs. Some are done to align with pipeline classification, while others are intended to enhance the aesthetics of the surrounding area; our company uses color for classification.