What liquid treatment scenarios are lined PTFE equipment suitable for?

2026-10-17 16:03:23

PTFE lining is the process of attaching polytetrafluoroethylene (commonly known as the "King of Plastics") to the inner wall of a metal substrate through lining, spraying or rotational molding processes. It combines the mechanical strength of metal equipment with the core advantages of PTFE: resistance to almost all strong acids, strong alkalis, strong oxidants and organic solvents, and high chemical inertness. It only reacts with a few media such as molten alkali metals and perfluoroalkanes under high temperature and pressure. It also features a low friction coefficient, non-stick property and good hygienic stability, so it is widely used in various liquid treatment scenarios with strict anti-corrosion requirements.

In the fine chemical and pharmaceutical industries, PTFE-lined equipment is the primary choice for treating strong acid and alkali systems. Such scenarios often involve corrosive fluids including concentrated hydrochloric acid, dilute nitric acid and organic acids. Traditional carbon steel and stainless steel equipment is prone to corrosion perforation and cross-contamination of materials. In contrast, PTFE lining can withstand cyclic contact with media such as sulfuric acid below 80% and concentrated nitric acid below 60% for a long time without chemical reactions with acids and alkalis, preventing the decline of product purity. For instance, in acid-base extraction processes for API production, PTFE-lined reactors and storage tanks prevent the precipitation of metal ions, comply with GMP hygienic standards for API manufacturing, and greatly reduce environmental risks from waste acid leakage.

Scenarios involving organic solvents and mixed media also rely on the properties of PTFE lining. Halogenated hydrocarbons, aromatic hydrocarbons, esters and other organic solvents, as well as multi-component mixed corrosive media, are highly corrosive to conventional resin linings and metal equipment. PTFE-lined pipelines and reaction equipment can operate stably within the range of -180℃ to 250℃, resisting long-term transportation and reaction of solvents such as chlorobenzene, dichloromethane and toluene. In solvent recovery systems for pesticide technical material synthesis, the non-stick surface of PTFE-lined distillation kettles reduces solvent residues, cuts cleaning frequency, and prevents impurities generated by solvent decomposition from mixing into finished products, improving recovery efficiency and product quality.

Food and pharmaceutical-grade liquid treatment imposes high requirements on the properties of PTFE lining. The production of food additives and pharmaceutical excipients prohibits the introduction of harmful impurities. PTFE lining complies with food contact material standards (such as China GB4806.7 and US FDA 21CFR standards). With excellent chemical stability, it will not release harmful substances in liquids such as citric acid, lactic acid and pharmaceutical polyethylene glycol. Therefore, it is widely applied in the transportation of acid hydrolysate for juice processing, neutralization reactions of pharmaceutical excipients and auxiliary treatment procedures for wine brewing. It replaces easily corroded FRP or ordinary rubber linings to guarantee the safety of food and pharmaceuticals.

For high-temperature, high-pressure corrosive fluids and particle-containing media, the temperature resistance and wear resistance advantages of PTFE lining stand out. Hydrometallurgy and sewage treatment often deal with dilute sulfuric acid leachate above 100℃ and acidic ore slurry with solid particles. High temperature accelerates metal corrosion while particles tend to abrade inner walls. The temperature resistance of PTFE lining can handle corrosive systems below 150℃. Its smooth inner wall resists scaling and offers better wear resistance than common lining materials. For example, in pipelines for transporting mine acidic ore slurry, the service life of PTFE-lined equipment is 3-5 times that of ordinary rubber linings, lowering costs for pipeline replacement and production shutdown losses.

In summary, with outstanding corrosion resistance, hygienic performance and durability, PTFE-lined equipment has been adopted in multiple sectors including fine chemicals, pharmaceuticals, food and metallurgy. It serves as a core solution for extreme-corrosion liquid treatment and suits critical industrial processes demanding high purity and long service life.