What are the applications of PTFE spray on valve rings in petroleum machinery

Source：www.dqig.cn Release date： 2025年09月08日

Information summary：Petroleum machinery valve rings are coated with polytetrafluoroethylene (PTFE, commonly known as "PTFE"), which utilizes the corrosion resistance, low friction coefficient, high temperature resistance, and strong sealing properties of PTFE to solve the "harsh working condition adaptation" and "sealing reliability" problems faced by valve rings in the processes of oil extraction, transportation, an

Petroleum machinery valve rings are coated with polytetrafluoroethylene (PTFE, commonly known as "PTFE"), which utilizes the corrosion resistance, low friction coefficient, high temperature resistance, and strong sealing properties of PTFE to solve the "harsh working condition adaptation" and "sealing reliability" problems faced by valve rings in the processes of oil extraction, transportation, and refining. Its application scenarios run through the core links of petroleum machinery, and can be disassembled according to industry processes as follows:
1、 Oil extraction process: adapted to high-pressure and highly corrosive conditions underground
The valve ring in the mining process needs to withstand high pressure, high temperature (deep well temperature exceeding 150 ℃), and multi-media corrosion (crude oil contains sulfur and chloride ions, and associated gas contains H ? S/CO ?). The PTFE spray coating can effectively solve these pain points and is mainly used for the following valves:
1. Valve ring of wellhead Christmas tree valve
The Christmas tree is the core equipment for controlling crude oil production at the wellhead, and the valve rings of its gate valves and globe valves need to be sealed for a long time for high-pressure crude oil and associated gas. The advantages of PTFE spray coating are reflected in:
Corrosion resistance: resist the erosion of sulfides and chloride ions in crude oil, and avoid wellhead leakage caused by sealing failure after valve ring corrosion;
High pressure sealing: PTFE has a certain degree of elasticity and can tightly adhere to the valve seat after spraying. Even under high pressure, it can maintain the integrity of the sealing surface and reduce the risk of "puncture leakage" (the phenomenon of high-pressure fluid penetrating the sealing surface).
2. Underground safety valve ring
The underground safety valve is a key component to ensure the safety of deep well mining (in case of emergency, the wellbore needs to be quickly closed), and its valve ring needs to operate frequently in high temperature and high pressure environments of deep wells. The low friction coefficient of PTFE spray coating (friction coefficient only 0.04-0.1, much lower than metal) can reduce the wear of valve rings and seats, and extend the service life of valves; At the same time, PTFE has high temperature resistance characteristics (long-term use temperature can reach 260 ℃), which can adapt to deep well high temperature working conditions, avoiding valve ring deformation due to high temperature aging.
2、 Oil transportation process: solving the sealing and wear-resistant requirements of long-distance pipelines
The valve rings in the oil transportation (pipeline transportation, tank transportation) process need to cope with long-term flushing of the medium, pressure fluctuations, and outdoor temperature differences. The "sealing stability+wear resistance" of PTFE spray coating has become a core requirement, mainly used for:
1. Valve ring for long-distance pipeline block valve/check valve
Block valves on long-distance pipelines (such as the West East Gas Pipeline) are used to urgently cut off fluids, while check valves are used to prevent medium backflow. The valve rings of both valves need to be sealed for a long time to avoid energy loss or safety accidents caused by leaks. Advantages of PTFE spray coating:
Anti erosion: Oil/natural gas flows at high speed in pipelines (flow rate can reach 3-5 m/s), and the wear resistance of PTFE layer can reduce the damage of medium erosion to the valve ring sealing surface;
Wide temperature sealing: Suitable for outdoor temperature differences of -40 ℃ (cold regions) to 60 ℃ (summer exposure), PTFE will not become brittle or soften due to drastic temperature changes, maintaining stable sealing performance.
2. Gate valve/ball valve ring in the storage tank area
The inlet and outlet valves (such as gate valves and ball valves) of oilfield storage tanks or refinery storage tanks need to seal the valve rings with media such as crude oil and finished oil. The chemical inertness of PTFE coating (which hardly reacts with any petroleum products) can prevent the valve ring from swelling or corrosion by the medium, and the low friction characteristics make the ball valve open and close more smoothly, reducing the resistance of manual/electric operation.
3、 Petroleum refining process: resistance to enhanced corrosion and high temperature conditions
The refining process involves strong acids (such as sulfuric acid, hydrochloric acid), strong bases (such as sodium hydroxide), organic solvents (such as benzene, toluene) and other highly corrosive media, and the reaction equipment is mostly located in high-temperature environments (such as distillation towers, reaction vessels). The corrosion resistance and high temperature resistance of valve rings are the core requirements, and the application of PTFE spray coating is concentrated in:
1. Control valve ring of refining equipment
Regulating valves are used to control the flow rate and pressure of media in refining processes (such as adjusting the feed of distillation towers and controlling the discharge of reaction kettles), and their valve rings need to be sealed under strong corrosion and high temperature. PTFE spray coating:
Corrosion resistance: resist the erosion of acids, alkalis, and organic solvents during the refining process, solve the problem of traditional rubber valve rings being easily corroded and metal valve rings being prone to scaling (due to medium adhesion leading to sealing failure);
High temperature stability: At the working temperature of 150-200 ℃ in the refining unit, the PTFE layer does not age or deform, ensuring the sealing accuracy of the regulating valve and avoiding the impact of sealing failure on process parameters (such as temperature and pressure fluctuations).
2. Valve ring at the outlet of the acid-base transfer pump
In refineries, acidic and alkaline media (such as ammonia water for desulfurization and sulfuric acid for refining) need to be transported through pumps, and the valve ring of the pump outlet valve needs to be sealed with strongly corrosive fluids. The chemical inertness of PTFE coating can completely isolate the medium from the valve ring substrate (usually metal), avoiding corrosion and perforation of the substrate. At the same time, the low friction coefficient reduces wear during valve opening and closing, extending maintenance cycles.

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