Why are PPR/PE/PB pipes not used for the selection of materials for hydrochloric acid pipelines in the chlor-alkali industry?

In the chlor-alkali industry, hydrochloric acid is a highly corrosive chemical, which imposes very strict requirements on the materials used for pipes used to transport or handle it. Although plastic materials such as PPR (polypropylene random copolymer), PE (polyethylene), and PB (polybutylene) possess a certain degree of corrosion resistance and are relatively inexpensive, and the heat fusion welding method can indeed provide good sealing properties, they are not typically used in the chlor-alkali industry for the following reasons: 1. Chemical resistance: Although PPR, PE, and PB have good resistance to chemical corrosion, it is inferior to that of CPVC (chlorinated polyvinyl chloride), rubber-lined pipes, or glass fiber reinforced pipes. CPVC exhibits superior resistance to acids, alkalis, and salt solutions, and it maintains good physical properties and chemical stability even under high-temperature conditions. Gasketed pipes and glass fiber reinforced plastic pipes also possess excellent corrosion resistance, especially against the chemicals commonly found in the chlor-alkali industry. 2. Heat resistance: The transportation of media such as hydrochloric acid in the chlor-alkali industry can involve high temperatures; the heat resistance of PPR, PE, and PB is generally lower than that of CPVC, which can operate continuously at higher temperatures without being damaged. 3. Physical and mechanical properties: CPVC, rubber-lined pipes, and glass fiber reinforced plastic pipes possess better mechanical properties; they can withstand higher operating pressures and have improved wear resistance. 4. Interfering factors: In the chlor-alkali industry, high purity levels are required for chemicals, and the use of plastics such as PPR, PE, and PB may pose a risk of contaminating the medium. 5. Cost-effectiveness: Although the initial investment cost may be slightly higher, in the long run, the durability and low maintenance costs of CPVC, rubber-lined pipes, and fiberglass pipes can make the overall cost more economical. 6. Installation and maintenance: CPVC, rubber-lined pipes, and fiberglass pipes may be easier to customize and install according to industrial environments, and may also be simpler to maintain. In summary, although PPR, PE, and PB pipes can also be used in certain environments, for industrial settings with high corrosion levels and stringent requirements such as the chlor-alkali industry, CPVC pipes, rubber-lined pipes, or glass fiber reinforced plastic pipes are generally the better choice due to their advantages in terms of corrosion resistance, temperature tolerance, physical and mechanical properties, as well as overall cost-effectiveness. .